Porous Ceramics for Environmental Protection, Energy-related Technologies and Advanced Industrial Cycles
Session CH-1 - Novel Processing and Synthesis of Porous Ceramics (Nano to Macro)
CH-1:IL01 The Application of Fluorotopaz Reaction Route for Fabrication Porous Mullite Ceramics
A. PYZIK, C. HAN, R. NEWMAN, C. TODD, M. MALANGA, The Dow Chemical Company, Midland, MI, USA
Porous ceramics are gaining technical importance as they are being used in many applications ranging from water treatment, gas separation, catalysis, metals purification to emission control. Even though all ceramics can be made porous only few enable broad enough range of achievable porosities, pore sizes and microstructural tuneability to create class of designed multifunctional materials. In this paper we discuss various approaches to create porous ceramics with the main focus on the in-situ formation of high aspect ratio grains, such as those growing in silicon nitride and acicular mullite. All these ceramics are based on standard raw materials which permits the use of commercial processes and shaping methods (e.g. casting, foaming or extrusion). In-situ growth of ceramic needles during high temperature reactions requires substantial mass rearrangement and transforms the entire microstructure. Depending on the nature of the transition process and amount of available liquid phase, the material can either (i) sinter, thus preventing further grain growth and reducing total amount of porosity in final part (as is illustrated in case of self-reinforced silicon nitride) or (ii) mechanically interlock grains preventing further sintering, thus enabling parts with porosity up to 85% while maintaining good mechanical integrity. This type of behavior will be demonstrated using examples of fluorotopaz and acicular mullite. The process of fluorotopaz formation and its later conversion to mullite will be discussed in detail. The effect of additives (naturally present in raw materials or purposely introduced in form of dopants) on grain growth mechanisms, microstructure evolution and formation of defects in acicular mullite ceramics will also be discussed. Finally, the advantages of acicular mullite high porosity and controlled pore size will be illustrated using examples of water filtration.
CH-1:IL02 Fabrication, Structure Control and Functional Characteristics of Hierarchically Structured Porous Ceramics
CHANG-AN WANG, State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, P.R. China
Hierarchical porous architectures, with different pore sizes (nano-, meso- and macro-pores) integrated in one body, are of great interest in fundamental research and practical applications in catalysis, lithium-ion batteries, and electrochemical capacitors, because they combine reduced resistance to diffusion and high surface areas to yield improved overall reaction and adsorption/separation performances. This report gives a brief introduction to the research progress on hierarchical porous ceramics in our group. Several hierarchical porous ceramics, including hollow ceramic spheres, monolithic bulk porous ceramics and core-shell structure hybrids, will be introduced from preparation, structure control and functional characteristics.
CH-1:L03 Synthesis of MFI Zeolite Membranes by Cross-Flow Seeding Procedure
C. ALGIERI, L. DONATO, A. GAROFALO, E. DRIOLI, National Research Council Institute for Membrane Technology (ITM-CNR) c/o The University of Calabria, Rende CS, Italy; O. ALHARBI, King Abdulaziz City for Science and Technology (KACST), Saudi Arabia
Zeolite membranes have attracted interest in many separation processes owing to their crystalline structure and to their pore diameters close to molecular size of different species. The most used methods for their preparation are the in situ and the secondary growth. The last one presents two steps: seeding and growth. In the first step, seeds are deposited on the support surface followed by a crystal growth. More controllable seeding involves the ﬁltration of a zeolite water slurry through a flat support . Nevertheless, coverage uniformity problems can happen when tubular supports are used. This problem can be overcame using a seeding where the cross-flow filtration is combined with the rotation and tilting of the support . In this work for the first time was demonstrate the possibility to prepare MFI zeolite membranes by using the new cross-flow seeding procedure. Morphology and thickness of the zeolite layer were observed by scanning electron microscopy. Topology of the crystals were examined by X-ray diffractometry. The separation properties were also investigated.
Acknowledgments: The research leading to these results has received funding from the King Abdulaziz City for Science and Technology (KACST) Kingdom of Saudi Arabia.
 M. Pera Titus, J. Llorens, F. Cunill, R. Mallada, J. Santamaria, Catal. Today 104 (2005) 281.
 C. Algieri, P. Bernardo, G. Barbieri, E. Drioli, Micropor. Mesopor. Mat. 119 (2009) 129.
CH-1:L04 Applications and Character of Porous Structures Produced Via Robocasting
J. CESARANO, J. STUECKER, M. NIEHAUS, Robocasting Enterprises LLC, Albuquerque, NM, USA
Robocasting is a versatile layered-manufacturing technique which uses CNC methods to extrude (or “print”) concentrated colloidal pastes into products with three-dimensional macrostructures and flow patterns that can not be easily attained with traditional manufacturing methods. Robocasting is particularly suited for the rapid creation of lattice structures comprised of cross-hatched layers of struts without the need for support materials or sacrificial molds.
Robocasting was originally conceived and developed at Sandia National Labs in 1996. Since then, the technology has been successfully spun-off into a private entity, Robocasting Enterprises LLC, and commercial viability for the manufacturing of porous structures is being realized.
This presentation will be used to review the character and performance of lattices for filtration (especially filtration of molten metals), catalyst supports with enhanced mass transfer, and load-bearing hydroxyapatite bone scaffolds. Comparisons and contrasts to honeycomb and reticulated foam structures will be discussed.
CH-1:L05 Synthesis of Particle-stabilized Zirconia Foam: Influence of Amphiphile Concentration on the Agglomeration of Zirconia Particles and Sintering Temperature on the Strut Wall Thickness
R. AHMAD1, 2, JANG-HOON HA2, IN-HYUCK SONG1, 2, 1University of Science & Technology (UST), Daejeon, Republic of Korea, 2Engineering Ceramic Department, Korea Institute of Materials Science, Gyeongnam, Republic of Korea
During the last decade, there has been a great interest to manufacture the porous ceramics utilizing the particle-stabilized direct foaming technique in order to fulfill the requirements of various applications. Aqueous foam stabilized by ceramic particles provides a method for producing macroporous materials due to their high stability against disproportionation and drainage. In the present study, highly porous zirconia ceramics were manufactured utilizing particle-stabilized direct foaming technique in which the hydrophilic character of zirconia particles was altered through in situ adsorption of valeric acid on its surface. These in situ surface modified zirconia particles are irreversibility adsorbed at air/water interface and stability of the foam is attributed to this adsorption. The foamability and drainage time of zirconia foams were investigated as a function of valeric acid concentration. The influence of valeric acid concentration on the cell size, porosity and agglomeration of zirconia particles was determined whereas the effect of sintering temperature on grain size, strut wall thickness, tetragonal phase and compressive strength was also investigated.
CH-1:IL06 Porous Silicate Materials: Synthesis and Control of the Microstructure
C.S. PEYRATOUT, A. DE MARCOS, B. NAIT-ALI, D.S. SMITH, C. PAGNOUX, GEMH-ENSCI Centre Européen de la Céramique, Limoges, France
Control of the microstructure is a key factor regarding thermal performances of insulating porous materials. This paper presents the synthesis of highly porous mineral materials (greater than 80% pore volume fraction) using two main synthetic routes, mainly direct foaming and freeze casting, and their thermal characterization with the laser flash technique. In a first part, the synthesis of porous clay or silica materials will be described, and various aspects, such as the behavior of the mineral phase during preparation, the microstructure, the drying step and the parameters controlling the porosity will be discussed. In a second part, the influence of various factors, such as the pore volume fraction, the pore orientation or the impact of hydraulic binders on the thermal conductivity of the resulting materials will be evaluated with laser flash measurements.
CH-1:IL07 Highly Transparent Glass Foams
M. SCHEFFLER, University of Magdeburg, Institute for Materials and Joining Technology, Magdeburg, Germany
Open cellular catalyst supports gain an increasing interest for microorganism or enzyme immobilization, for artificial photosynthesis, for exhaust gas treatment and for environmental catalysis. In combination with photocatalytical active components, a high light transmittance over a specific wavelength range is necessary for the activation of the catalyst component.
In the last few years novel processing routes were developed for the production of highly transparent cellular glasses. The first part of this paper gives an overview of methods and cellular glass structures with a high transparancy in the visible rage. In the second part a specific method for the production of open cellular borosilicate glass foams will be presented, and some strategies will be discussed to manufacture photocatalyst glass foam reactors.
CH-1:L08 Microstructure Control of Particle-Stabilized Mullite Foams and Emulsions
E.R. KUPP, G.L. MESSING, Penn State University, University Park, PA, USA; A.J. Pyzik, Dow Chemical Co, Midland, MI, USA
Particle-stabilized foams and emulsions yield stable green bodies which, when dried and sintered, produce ceramics with tailorable pore sizes and porosity. Both of these processes utilize short-tail amphiphiles to stabilize either bubbles (i.e., foams) or oil droplets (i.e., emulsions) lined with ceramic particles. Processing variables such as amphiphile type/concentration and shear rate are common to both techniques and were utilized to control the final microstructures of the ceramics. By systematically studying each of these variables, processing parameters were developed for producing foams with porosities as high as >90% and 300-500 µm pores and emulsions with porosities as high as 90% and pore diameters of 20-30 µm. To produce mullite ceramics, alumina and clay powders were mixed in slurries that were foamed or emulsified, then dried before undergoing a two-step thermochemical process to convert these materials into structures containing interlocking mullite needles. Images, pre- and post-mullitization, and data detailing the effects of the processing variables mentioned above on part microstructures will be presented.
CH-1:IL10 Processing of Ceramic Membranes with successive Macro-, Meso- and Microporous Layers
T. VAN GESTEL, W.A. MEULENBERG, H.P. BUCHKREMER, Forschungszentrum Jülich, IEK-1, Germany
Porous ceramic membranes are today considered for industrially relevant membrane separation applications such as (nano)filtration, desalination, pervaporation (liquid/liquid separation) and gas separation. The membranes are typically multilayered, consisting of a porous support material and layers with various porosities (macro-, meso-, microporous). The scope of this paper is mainly on the functional thin film meso- and microporous layers. In the first part, processing of various mesoporous layers (Al2O3, ZrO2, CeO2) with a reproducible pore size of 5 nm and 2-3 nm is reported. For applications at high temperatures, stabilized ZrO2 (8YSZ) and CeO2 (10GDC) membranes have been developed. In the second part, the existing mesoporous membranes are modified with additional microporous layers. Membrane materials include e.g. amorphous SiO2 and hybrid carbon-SiO2 for gas separation and pervaporation and TiO2 and ZrO2 for nanofiltration. Processing methods reported in this paper are mainly based on sol-gel processes and comparable nanoparticle deposition processes. Three different thin film coating techniques have been studied: dip-coating, spin-coating and inkt-jet printing. For rapid production, the coating processes are combined with a rapid thermal process (RTP).
CH-1:IL11 Macroporous Ceramics by Gelation Freezing Route Using Gelatin
M. FUKUSHIMA, T. OHJI, Y.-I. YOSHIZAWA, National Institute of Advanced Industrial Science and Technology, AIST, Nagoya, Japan
This study proposes an advanced gelation-freezing methodology for macroporous ceramic components, that can create nearly honeycomb shaped pore channels, unlike either ellipsoidal or dendric or lamellar structures obtained via conventional aqueous freeze casting. Three main technological features have been discussed in terms of 1) honeycomb shaped porous structures, 2) relationship between carefully selected freezing conditions and cell properties generated and 3) engineering properties and applications of cellular monoliths. This simple, ecofriendly and versatile approach tailors porous architecture with engineered porosity and yields macro-cellular component with distinctive characteristics of fluid permeability, mechanical properties, machinability, electrochemical performance and thermal insulation properties, suitable for a variety of industrial applications.
CH-1:L12 Geopolymer Foams by Gelcasting
M. STROZI CILLA1, 2, M.R. MORELLI1, P. COLOMBO2, 1Federal University of São Carlos (UFSCar) - Graduate Program on Materials Science and Engineering (PPG-CEM), São Carlos-SP-Brazil; 2Università degli Studi di Padova (UNIPD) - Dipartimento di Ingegneria Industriale, Padova, Italy
Highly porous geopolymers, with homogeneous microstructure, open cells and porosity up to 90 vol%, were fabricated by gel-casting, a process commonly used to produce ceramic foams. Geopolymer foams were prepared by stirring an activated blend of metakaolin and fly ash with a mixture of potassium hydroxide and potassium silicate with Si/K = 1.66. The cell size and size distribution of the geopolymer foams could be efficiently adjusted by the control of some parameters such as solid content, surfactant type and content and mixing speed. The influence of each parameter on the porosity and other characteristics of the geopolymer foams were investigated. The foams were evaluated only after heat treatment at 80°C, which was conducted in order to complete the geopolymerization reactions. The produced components could be heat treated up to 1200°C in air without melting, if desired.
The characteristics (morphology, strength, chemical and thermal resistance) of this geopolymer foam suggest that they could be employed as low cost replacement of porous ceramics in applications such as catalysis supports, adsorption and separation, filtration of hot gases and refractory insulation of furnaces. In addition, these components could be considered sustainable as they reach their final properties after processing at temperatures not exceeding 100°C and part of the raw materials employed are industrial waste.
CH-1:L13 Multi-layered Porous Ceramic Membranes with Tunable Porosity and Zeta-potential for Filtration and Purification Technology
C. BRANDES, L. TRECCANI, K. REZWAN, Advanced Ceramics, University of Bremen, Bremen, Germany
Membranes (MEs) with structured hierarchical, tunable meso- and macroporous pore structures, high specific surface area and a controlled surface charge have become particular relevant for an increasing number of technological applications. However, their fabrication is still highly challenging. We present a novel, straightforward, environmentally friendly gel-casting process based on ionotropic-gelation (GCIG) of alginate to fabricate multi-layered, porous ceramic MEs. By this versatile approach, alumina, silica, zirconia and titania MEs featuring an open porosity ~40vol% and adjustable pore sizes from 5nm up to the 1.5μm can be easily obtained. Moreover, by our approach ceramic slurries with up to 50% powder volume can be easily processed and pore size can be predicted with high accuracy prior fabrication. By stacking different materials layered-MEs with different surface charges and potentials can be obtained. This is particularly attractive for MEs for simultaneous size exclusion and separation of differently charged compounds. In summary, we show that the GCIG method is an easy and sustainable approach for fabricating MEs with tunable and predictable pore size, porosity and zeta-potential for obtaining tailor-made ceramic filters for e.g. purification purposes.
CH-1:L14 Fabricating of Diatomite Based Ceramic Water Filter by A Novel Casting Method
E. AL1, U.E. ANIL1, K. KAYACI1, F. KARA2, 1Kaleseramik Canakkale Kalebodur Seramik San. A.S., Can-Canakkale, Turkey; 2Department of Materials Science and Engineering, Anadolu University, Eskisehir, Turkey
In this study, a ceramic water filter with micron sized pores was developed based on diatomite raw material. The slip with diatomite earth which has tubular shaped particles was prepared by using water and different binders (nano silica solution and agar). Agar is a gelatinous materials derived from sea alges and used as a gelling agent in order to form ceramic filters by slip casting. Rheology of the slip was investigated by rheometry. In the forming process, polymer and metal moulds were used instead of plaster moulds. After demoulding, the ceramic filter samples were dried and fired at 1200 0C/1 h. Density, phase analysis and microstructure properties of the porous diatomite based filter material were measured and characterised by He picnometer, XRD and SEM, respectively. Water filtration performance and microbiological tests were also performed.
Session CH-2 - Physics, Chemistry Structure and Properties of Porous Systems
CH-2:IL01 Surface Chemistry of Cellular Glasses
B. REINHARDT, N. ANDERS, C. KUESTER, D. ENKE, Universität Leipzig, Institute of Chemical Technology, Leipzig, Germany
A very typical synthesis strategy for cellular glasses is the replication method. The resulting materials potentially feature all possibilities regarding surface modification compared to fused silica. Unfortunately due to their large pore diameters the specific surface area is very low. This makes the characterization and surface modification difficult. Recently, hierarchically structured glass foams were synthesized via a combination of the replication method with phase separation and selective leaching of alkali borosilicate glasses. As a result of an additional micro- or mesoporosity inside the glass struts of the foam the new materials show a high specific surface area. This allows an effective modification of the glass surface. Due to the preparation process, the glass foams show a slightly different surface chemistry compared to fused silica (existence of different boron species). This study wants to present the surface chemistry of porous glass based foams, characterized by IR, Solid-State-NMR and Inverse Gas Chromatography. Additionally, different modification routes and applications of the monolithic materials for gas chromatographic separation of chiral anesthetic gases and for a pesticide detecting sensor are presented.
CH-2:IL02 Chemistry and Hydrogen Gas Permeation Properties of Microporous Amorphous Silica-based Ceramic Membranes
Y. IWAMOTO, Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
Amorphous silica membranes exhibit an excellent hydrogen perm-selectivity, which could be achieved by the molecular sieve-like functionality derived from the in-situ formed microporous amorphous silica network having a suitable mean pore diameter of approximately 0.3 nm. In this paper, recent progress in the development of the hydrogen-permselective amorphous silica-based membranes will be briefly reviewed. Then, our study of novel amorphous silica-based composite membranes having chemical affinity will be shown and discussed. For hydrogen separation, amorphous silica-based membranes with ternary or quaternary system were synthesized using chemical solution precursors. According to our primary results, by doping transition metal cations expected to have hydrogen affinity, the synthesized membranes successfully exhibited a unique enhanced hydrogen permeance.
The chemical structure, especially the local structure around the doped hetero element in the membrane materials, the related chemical affinities towards hydrogen, and the hydrogen gas permeation properties will be discussed based on the characterization results obtained by the X-ray diffraction (XRD), FT-IR (using DRIFTS technique), the TPR/TPD analysis and so on.
CH-2:L03 Development and Mechanical Characterization of Novel Ceramic Foams Fabricated by Gelcasting
J.M. TULLIANI1, M. LOMBARDI1, P. PALMERO1, M. FORNABAIO1, L.J. GIBSON2, 1Politecnico di Torino, Department of Applied Science and Technology, Torino, Italy; 2Department of Materials Science and Engineering, MIT, Cambridge, MA, USA
Porous ceramic materials are of considerable interest for a variety of chemical and industrial applications in extremely harsh conditions, particularly at very high temperatures for long times. A combined gelcasting - fugitive phase process employing agar as a natural gelling agent and polyethylene spheres as pore formers was exploited to produce porous ceramic bodies. Alumina and alumina-zirconia powders were used to prepare samples having a porosity of about 65-70-75 vol%. The composite powder was produced by a surface modification route, i.e. by coating a well dispersed alpha-alumina powder with a zirconium chloride aqueous solution. Upon thermal treatment, ultra-fine tetragonal zirconia grains formed on the surface of the alumina particles. SEM observations and image analysis were used to characterize the microstructure of porous samples and uniaxial compressive tests were carried out to measure their mechanical behavior. The porous composite samples have a higher compressive strength than the pure alumina ones, probably because of smaller pores due to a higher shrinkage during sintering. In fact, the small size of the tetragonal grains in these samples probably reduced their transformability to monoclinic phase under the applied stress.
CH-2:IL04 Control of the Thermal Radiative Properties of Ceramic Foams: Application for the Design of Efficient Volumetric Solar Receivers
B. ROUSSEAU, S. GUEVELOU, G. DOMINGUES, LTN UMR 6607, Nantes, France; J. VICENTE, IUSTI UMR 7343, Marseille, France; C. CALIOT, G. FLAMANT, PROMES UPR 8521, Odeillo, France
Because of their light weight, open porosity, high volumetric surface and thermal characteristics, ceramic foams are promising materials for many industrial applications involving fluid flow and heat transfer. This dual feature is particularly researched for developing efficient volumetric solar absorbers used for solar thermal energy processes. These absorbers must deliver hot air in the temperature around 1400 K in order to increase the yielding of solar energy conversion over 50 %. Among the various existing technologies, only refractory ceramic foams seem able to reach air temperature of 1400K. Then, the foams must absorb solar radiation in their whole volumes while minimizing scattered reflections and infrared emission losses. This situation involves the optimization of both the texture and the chemical composition of the selected foams. To achieve this goal, a numerical tool was developed to design foams with realistic textural features. Then the radiative properties can be computed with the freely iMorphRad by using suitable complex refractive index for the solid constituents. The calculated data are compared with experimental properties or with results computed with idealized foams. Finally, solutions to optimize the radiative properties will be proposed.
CH-2:IL05 Thermal Properties of Ceramics
D.S. SMITH, GEMH-ENSCI Centre Européen de la Céramique, Limoges, France
Polycrystalline ceramics often contain a pore volume fraction varying from < 1% to > 95%. This paper discusses how the pore phase modulates the thermal properties with a particular focus on the microstructural factors which strongly decrease the thermal conductivity; relevant to thermal insulation. Earlier work on dense ceramics has shown that a thermal resistance of the order of 1 x 10-8 m2KW-1 can be attributed to the grain boundary. Smaller grain size thus decreases significantly the solid phase thermal conductivity in oxides like alumina and tin oxide. At the macroscopic scale, a tool box of analytical relations is proposed to describe the effective thermal conductivity of the porous ceramic as a function of solid phase thermal conductivity, pore thermal conductivity and pore volume fraction (vp). For vp < 0.65, the Maxwell-Eucken relation for closed porosity and Landauer relation for open porosity give good agreement to measurements on tin oxide, alumina and zirconia. For vp > 0.65, the room temperature thermal conductivity of kaolin based foams and silica aerogels can be described by analytical relations based on closed/open cells depending on the pore connectivity. At higher temperatures radiation heat transfer should be taken into account.
CH-2:L06 Ceramic Capillary Membranes with Adjustable Pore Size for Controlled Virus Retention
J. WERNER, B. BESSER, S. KROLL, K. REZWAN, University of Bremen, Advanced Ceramics, Bremen, Germany
In this study, porous ceramic capillary membranes made of yttria-stabilized zirconia (YSZ) are presented, which are conditioned for virus filtration by varying the initial YSZ particle size. YSZ powders with particle sizes of 30 nm, 40 nm and 90 nm in combination with convenient contents of dispersant (3-aminopropyltriethoxysilane) and binder (polyvinyl alcohol) are individually processed by extrusion, dried and finally sintered at 1050 °C for 2 h. The sintered YSZ capillaries are characterized by microstructural analysis including Hg intrusion porosimetry, BET analysis and three-point bending tests. Depending on the initial YSZ particle size average pore sizes (d50) of the extruded and sintered capillaries of 27 nm, 53 nm and 220 nm are obtained in combination with high open porosities of nearly 45 % and sufficient mechanical stabilities. By increasing the membrane pore size, reduced virus retention capacities in combination with increased water permeate fluxes are achieved. Capillaries made of YSZ-40nm ensure both, log reduction values (LRV) > 4 for model viruses MS2 and PhiX174 and high water permeate fluxes, being suitable for sustainable virus filtration.
CH-2:L07 Thermomechanical Properties of Macro-porous Alumina
V.R. SALVINI, D. SPINELLI, University of Sao Paulo, Sao Carlos School of Engineering, Department of Materials Engineering, EESC-USP, Sao Carlos, SP, Brazil; V.C. PANDOLFELLI, Federal University of Sao Carlos, Department of Materials Engineering, Materials Microstructure Engineering Group, UFSCar, DEMa-GEMM Sao Carlos, SP, Brazil
In recent years macro-porous ceramics have received much attention due to their properties, which offer important economic benefits in energy savings and environmental applications. These materials present key properties such as high volume of pores larger than 50nm, low density, controlled permeability, high surface area, and low thermal conductivity at high temperatures. These properties have many uses as filters at different levels, catalysis supports and thermal insulating ceramics.
However, in many structural applications they are subjected to mechanical stresses and cycled thermal shocks. The analysis of porous ceramics suggests that there is a strong interaction of cracks with their porous in the microstructure. Therefore, the understanding of the thermomechanical behavior of these materials is an important aspect for selection and design for structural applications.
In this paper, the thermomechanical properties of macro-porous alumina (Al2O3) are presented and correlated to their microstructure. Foamed ceramic samples with high porosity (>70%), low thermal conductivity at high temperature (<1W/mK) and high flexural mechanical strength (~15MPa) were designed for this work and produced by the green direct-foaming method developed by the authors.
Session CH-3 - Advances in the Characterization of the Porous Structure
CH-3:IL01 Recent Advances in the Structural Characterization of Porous Ceramics
M. THOMMES, Quantachrome Corporation, Boynton Beach, FL, USA
A comprehensive textural characterization of porous ceramics with regard to surface area, pore size and porosity has become more important than ever for the optimization of many important existing and potentially new applications. Gas adsorption and mercury porosimetry based techniques are widely used for this task Within this context major progress has been achieved during the last two decades concerning the understanding of the underlying mechanisms of the adsorption and phase behavior of fluids confined to ordered micro-mesoporous materials. On the other hand, well defined, novel meso/macroporous model materials have allowed one to obtain new insights into the mechanism of mercury intrusion/extrusion. We will review these results obtained over the last two decades and will discuss consequences for the textural characterization of porous ceramics.We will also focus on a novel method based on electroacoustics and electric conductivity measurements for the pore size and porosity analysis of meso/macroporous ceramics.
CH-3:IL02 Characterization of Aerogels - Challenges and Prospects
G. REICHENAUER, Bavarian Center for Applied Energy Research, Würzburg, Germany
"Aerogel" denotes a special class of nanoporous solids and composites with an open porosity of 85 % or more. The chemical composition of their solid backbone can deliberately be chosen to be inorganic (e.g. silica, zirkonia), organic (e.g. resin like or based on natural components) or to consist of carbon.
Aerogels provide huge, well accessible specific surface areas and high porosities in combination with easily tuneable nanosized pores. They are therefore candidates for applications such as drug release, filtering, catalyst supports, thermal superinsulations, charge and gas storage, to just name a few. The structural key parameters of aerogels are the specific surface area, the pore size distribution, the pore and solid phase connectivity and the substructure and surface chemistry of the solid backbone.
However, the properties responsible for their uniqueness can also cause severe artifacts when using characterization techniques that are well establish for other types of materials, such as N2 sorption analysis or Hg porosimetry.
The paper critically reviews standard techniques and introduces novel characterization methods that can be applied to determine structural properties of aerogels. The new approaches also provide a deeper insight in the physics dominating at nanoscale.
CH-3:IL03 Characterization of Porous Materials using High Resolution SEM
A. ENDO, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
Porous materials whose pore size is roughly between those of micropores and mesopores, e.g. highly ordered mesoporous materials templated by surfactant molecular assemblies such as MCM-41, SBA-15, and hierarchical mesoporous zeolites, have attracted a lot of attention in terms of both scientific interest and potential industrial applications. In line with this trend, it has become increasingly important to establish a methodology for evaluating the nano-structure of these materials because a porous structure has a great effect on the characteristics and performance of materials in practical applications. Recent progress on scanning electron microscope (SEM) technologies, especially low energy imaging techniques without a metal coating, have enabled us to observe the porous structure in a nanometer scale. I will report results for the direct imaging of the surface and inner structure of mesoporous silica materials and hierarchical mesoporous zeolites using a low acceleration voltage FE-SEM with recently developed techniques, such as beam retarding and line averaging scanning techniques which offer a solution to the charging problems and the beam damage, and broad ion milling (BIB) method for the fabrication of cross-section by gentle argon ions.
CH-3:IL04 Characterization of Cellular Ceramics and MMC by in Situ Computer Tomography
H. BEREK, J. HUBALKOVA, C.G. ANEZIRIS, TU Bergakademie Freiberg, Institute of Ceramics, Glass and Construction Materials, Freiberg, Germany
The aim of this lecture is to illustrate the potential of in situ computer tomography for the investigation of cellular materials. The principle of micro-computer tomography using laboratory X-ray sources is described briefly. A review of the different in situ experimental setups in the literature is given. Examples of stopped in situ compressive deformation experiments are presented and discussed. They include ceramic and MMC foams of the same manufacturing technology and geometry based on alumina and TRIP-steel/Mg-PSZ respectively. The dominant deformation and failure mechanisms are outlined. Examples for crack initiation and crack propagation in foam glass and autoclaved aerated concrete are given. Furthermore, the influence of the cellular macrostructure on the fracture mechanics is demonstrated for MMC honeycombs and MMC foams with the same composition. Future perspectives and limitations of laboratory in situ techniques are discussed in summary.
CH-3:L05 Evaluating Porosity in Cordierite Diesel Particulate Filter Materials: Advanced X-ray Techniques and New Statistical Analysis Methods
A. KUPSCH, A. LANGE, M.P. HENTSCHEL, Y. ONEL, T. WOLK, A. STAUDE, K. EHRIG, B.R. MÜLLER, G. BRUNO, BAM, Federal Institute for Materials Research and Testing, Berlin, Germany
Bi-continuous porous ceramics for filtration applications possess a particularly complicated microstructure, whereby porosity and solid matter are intermingled. Mechanical, thermal, and filtration properties can only be precisely estimated if the morphology of both solid matter and porosity can be quantitatively determined. Using 3D computed tomography (CT) at different resolutions, and several X-ray refraction-based techniques, we quantitatively evaluated porosity and pore orientation in cordierite diesel particulate filter ceramics.
Moreover, applying both Fast Fourier Transform (FFT) and a newly developed image analysis algorithm (directional interface variance analysis, DIVA), we quantitatively evaluated porosity and pore orientation. Both the experimental techniques and the statistical approach allow extraction of spatially resolved or average values.
Porosity values estimated by all experimental techniques used turn out to agree with mercury intrusion measurements, while pore orientation factors agree with published crystallographic texture data. This latter point also implies that the study of the pore/matter interface is sufficient to describe the morphological properties of these materials.
Session CH-4 - Modelling and Simulation of Porous Structures and Properties
CH-4:IL01 Modelling of Cellular Structures on the Basis of Computer Tomographical Data
T. FEY, B. CERON-NICOLAT, B. ZIERATH, M. STUMPF, F. EICHHORN, A. KOSHRAVANI, P. GREIL, University Erlangen-Nürnberg (FAU), Erlangen, Germany
Cellular materials offer a wide spectrum of applications such as catalyst support structures, lightweight materials, energy adsorption or energy storage materials. Due to several ways of processing and materials a wide range of material properties e.g. thermal conductivity, mechanical strength or dumping can be adjusted, measured and verified. Especially in heterogeneous structures only global effective material properties can be easily measured and influence of microstructure on these properties is hard to determine. To fill this gap and enable a "look-in", a microstructure model derived from µ-CT measurements carried out at certain processing steps can be used as model for FEM-calculations. Combing estimated material properties by experiment with microstructure models offers the possibility to carry out different simulations over different hierarchical levels. In contrast to experiments also the pore network and its influence on global parameter can be analyzed. This approach is carried out on different cellular structures as heterogeneous ceramic foams, homogenous lattice structures and syntactic foams.
CH-4:IL02 CFD Approach to Analyze and Design Thermo-fluid Dynamics Properties of Ceramic Foams and Lattices
M. BARBATO, ICIMSI – DTI – SUPSI, Manno, Switzerland
Si-SiC foams and lattices are a new category of materials that are increasing their use in advanced technologies such as concentrated solar power and space. These systems are effective thanks to their characteristic thermal properties and their behavior at high temperature and harsh environments.
The study of the factors that contributes to these materials performance, besides experimental approaches, is nowadays effectively achieved exploiting simulations methods such as Computational Fluid Dynamics.
This work proposes an overview of the CFD methods suitable to simulate air-flow through Si-SiC foams and lattices and then focuses on three-dimensional thermo-fluid dynamics analyses performed to evaluate their fluid dynamics and heat transport properties. Furthermore, the studies presented here aimed at designing the specific morphology of Si-SiC lattices structures targeting certain performance. This foams and lattice design was done looking at the customization of performance for demanding applications such as volumetric solar receivers and spacecraft thermal protection systems.
CH-4:IL03 Adsorption Deformation of Micro- and Mesoporous Solids
A.V. NEIMARK, Rutgers University, Piscataway, USA
Phenomenon of adsorption-induced deformation attracted recently a considerable attention owing to its relevance to practical problems of mechanical stability and integrity of novel micro- and mesoporous materials and their adsorption properties. Guest molecules adsorbed in nanoscale pores cause a substantial stress in the host matrix leading to its contraction or swelling depending on the specifics of host-guest interactions. Although various experimental manifestations of adsorption-induced deformation were known for a long time, a rigorous theoretical description of this phenomenon has been lacking. I will present a general thermodynamic method to predicting adsorption stress and respective deformation in various microporous and mesoporous materials based on molecular models of adsorption within elastic porous media. The proposed theoretical method will be illustrated with examples of microporous solids, like zeolites , and mesoporous solids of ordered and disordered structures, like porous glass and templated silica [2,3].
1. P.I. Ravikovitch and A.V. Neimark, Langmuir, 2006, 22, 10864.
2. G. Yu. Gor and A.V. Neimark, Langmuir, 2011, 27, 6926; 2010, 26, 13021.
3. G.Yu. Gor, O. Paris, J. Prass, P.A. Russo, M.M.L. Ribeiro-Carrott, and A.V. Neimark, Langmuir, 2013, 29, 8601.
CH-4:L04 Study of Pore Grain-boundary Interactions in the Final Stage of Sintering using the Phase-field Method
J. HOETZER, G. BARTHELEMY, B. NESTLER, Karlsruhe Institute of Technology (KIT), Baden-Württemberg, Germany
In the final stage of sintering processes, grain growth is influenced by the presence of pores. The various interactions between grains and pores are known as pore drag, pore drop and Zener pinning. A phase-field model for multiple order parameters is employed to study the influence of pores on the grain boundary evolution by 3D microstructure simulations. The model is generally formulated and allows to distinguish the mobility of each grain-grain and pore-grain boundary, respectively. We further present an extension of the phase-field model computing the pressure of the pores by locally solving the ideal gas law. The model covers interaction events such as combining, separating and dissolution of pores. In order to investigate large scale realistic structures, the solver is parallelized using domain decomposition techniques based on MPI standards. The model is capable to describe all three effects, pore drag, pore drop as well as the so-called Zener pinning observed in realistic structures. Results are presented for parametric studies with different surface energies, mobility ratios between grain-grain and pore-grain boundaries, pore size and grain size distributions respectively. We compare our results with experiments, analytical solutions and other numerical models.
CH-4:IL05 Modeling the Properties of Cellular Ceramics: From Foams to Lattices and Back to Foams
A. ORTONA, SUPSI, Manno, Switzerland
Cellular ceramics are attracting material solutions for high temperature applications because of their outstanding properties. SiC cellular ceramics in particular withstand harsh environments at high temperatures for long operating times and are particularly resistant to thermal shock. Ceramic foams though, being random fragile structures, comprise properties which are rather scattered and difficult to engineer.
This presentation shows how finite element analysis is used to study the effect of morphological features on ceramic foams in respect of their mechanical properties. Mean morphological parameters, obtained by X- ray computed tomography (XCT) on a commercially available SiSiC foam produced by the replica method, were used to generate a set of lattices in which one parameter was varied at a time. Starting from this approach, further work was then dedicated to optimize their properties.
Polymeric lattices and foams, in which some characteristics were digitally modified learning from the optimization work were, produced by 3D printing and ceramized via the replica method. Both foams and lattices were then mechanically tested.
Results show that some features such as strut shape and cell stretching affect the mechanical behavior of ceramic foams.
CH-4:IL06 Quantitative Morphology-transport Relationships for Disordered Porous Media by Morphological Reconstruction and High-performance Computing of Flow and Transport
U. TALLAREK, Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
The discovery of the morphology-transport relationships for disordered porous media used in chemical engineering and separation science (packings, monoliths) is a major challenge, because it requires the 3D physical reconstruction and/or computer-generation of the materials followed by 3D mass transport simulations to collect meaningful data for morphological and transport properties. This approach is the only direct as well as the most realistic way to understand and optimize materials with applications in chromatography or catalysis. Our latest progress regarding the following issues will be reported: (1) Systematic study of how individual parameters, such as the packing density and packing protocol, affect the morphology of computer-generated packings. (2) Physical reconstruction of packed and monolithic beds to collect information on how experimental parameters of the packing and preparation process influence morphology. (3) 3D mass transport simulations performed on a high-performance computing platform to analyze in detail diffusion and dispersion. (4) Analysis of computer-generated and physically reconstructed packed and monolithic beds with statistical methods to derive structural descriptors for mass transport, which help to refine the existing theoretical framework.
Session CH-5 - Applications of Porous Ceramics
CH-5:IL01 Porous Medium Combustion Technology and its Application to Internal Combustion Engines
M. WECLAS, Georg-Simon-Ohm-University of Applied Sciences Nuremberg, Technische Hochschule Nürnberg, Nuernberg, Germany
Why do we still need new concepts for Internal Combustion engines? Future internal combustion engines must perform a clean and efficient combustion (homogeneous process). Practical realization of such a process in engine requires control of many parameters: self-ignition timing, combustion duration, heat release rate, pressure peaks and gradients, control of combustion temperature, and completeness of the process. A novel kind of engine with combustion in porous reactor may realize a homogeneous combustion and is characterized by very clean exhaust gases and high cycle efficiency. Combustion technology in highly porous, open cell 3D-reactors is presented and its potential under diesel engine-like conditions is discussed in the paper. Heat release process in porous reactors has been analyzed under diesel engine-like conditions. Diesel spray interaction with porous structures is discussed in the paper. This process creates boundary conditions for mixture homogenization inside combustion reactor under high pressure direct fuel injection. Characteristic modes of heat release process have been defined in a two-dimensional field of initial reactor pressure and temperature. The modes are influenced by reactor heat capacity, pore density and pore structure and, as found, show despite reduced combustion temperature, a qualitative similarity to the process in a free volume combustion chamber. This similarity indicates applicability of the engine concept with combustion reactor to real internal combustion engine conditions.
CH-5:IL02 Porous Silicas for Enhanced Drug Release
A.M. CREAN1, R.J. AHERN1, J.P. HANRAHAN2, J.M. TOBIN2, K.B. RYAN1, 1School of Pharmacy, University College Cork, Ireland; 2Glantreo Ltd, Cork, Ireland
Loading a poorly water-soluble drug onto a high surface area carrier such as mesoporous silica (SBA-15) can increase the drug's dissolution rate and oral bioavailability. The loading method can influence subsequent drug properties including solid state structure and release rate. The objective of this research was to investigate different loading processes and parameters on drug distribution throughout the mesoporous silica matrix, drug solid state form and subsequent drug release properties. The model poorly water-soluble drug selected was fenofibrate. Physical mixing resulted in heterogeneous drug-loading, with no evidence of drug in the mesopores and the retention of the drug in its crystalline state. The other loading processes yielded more homogeneous drug-loading; the drug was deposited into the mesopores of the SBA-15 and was non-crystalline. All the processing methods resulted in enhanced drug release compared to the unprocessed drug. An in-vivo preclinical pig study demonstrated that in-vitro release results translated into improved in-vivo performance of these systems following oral administration and comparable bioavailability to a marketed fenofibrate product Lipanthyl Supra®.
CH-5:L03 CeO2-based Ceramic Foams for Syngas Production by a Solar Driven RedOx Cycle
A. BONK1,2, M. GORBAR1, A. ZUETTEL1, A. STEINFELD3, U.F. VOGT1,2, 1Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Hydrogen & Energy, Dübendorf, Switzerland; 2University of Freiburg, Department of Crystallography, Freiburg i. Brsg.; 3Department of Mechanical and Process Engineering, ETH Zurich, Zurich
Solar thermochemical RedOx cycles based on metal oxides can be used to reduce water and CO2 to form H2 and CO, respectively. Due to its excellent thermodynamic and kinetic properties, cerium dioxide is one of the most promising non-volatile metal oxides in this context. In a 2-step solar thermochemical cycle, above 1400°C ceria will release oxygen from its lattice, to form nonstoichiometric Ceria (CeO2-δ). In the next step, oxygen vacancies react with CO2 and/or H2O to form CO and H2, respectively at around 900°C. Stoichiometric CeO2 is regained, closing the RedOx cycle.
In this study we developed chemically homogeneous, as well as mechanically stable porous ceramics for solar driven thermochemical cycles.
The control of thermodynamics, kinetics and the transport of concentrated solar energy to the reactant is essential to design highly efficient ceria based structures. For this purpose, ceria was doped with isovalent cations. Samples have been investigated regarding their RedOx potential, phase purity as well as their sintering behaviour at high temperatures using thermogravimetric analysis, X-ray diffraction and electron microscopy.
CH-5:L04 Lightweight Bi-layered Ceramic Tiles for Novel Applications
R.M. NOVAIS, M.P. SEABRA, J.A. LABRINCHA, Materials and Ceramic Engineering Department, CICECO University of Aveiro, Aveiro, Portugal
The interest on the fabrication of multiple-layered ceramics has grown over the past years.
Common processing techniques are not doable for industrial application, since they usually are time consuming and expensive processes. Therefore the development of novel methods, enabling mass production of macro multiple-layered ceramics is of the utmost importance.
The present work focuses on the development of bi-layered ceramics, formed by layers with distinct density - dense/porous - and with adjustable thicknesses. The processing method is easy to implement and ensures the development of a perfect interface bonding between the two layers.
The bi-layered ceramic body is formed by an upper layer showing the typical properties of a commercial product, and by a porous bottom layer. Results demonstrate that the produced tiles are lighter than conventional porcelain stoneware tiles, yet maintaining suitable mechanical strength. Their thermal conductivity was also considerably reduced.
Recent market trends suggest interest on developing lightweight products for novel applications, such as ventilated facades.The produced tiles could be an effective alternative to conventional materials. Moreover, when applied inside buildings they allow energy saving due to thermal insulating properties.
CH-5:L05 Thermochemical Solar Energy Storage via Functionalized Porous Ceramic Structures
C. AGRAFIOTIS, M. ROEB, C. SATTLER, Deutsches Zentrum für Luft- und Raumfahrt/German Aerospace Center - DLR, Köln, Germany
Thermochemical storage of solar heat in Concentrated Solar Power (CSP) plants exploits the heat effects of reversible chemical reactions: solar heat produced during on-sun operation is used to power an endothermic chemical reaction; if this reaction is completely reversible the thermal energy can be entirely recovered by the reverse reaction during off-sun operation. Redox reactions of multivalent solid oxides in particular, can be directly coupled to CSP plants using air as heat transfer fluid, since in this case air can be simultaneously used as a reactant in the storage system.
In such applications, the inherent advantages of porous ceramic foams/honeycombs i.e. high geometric surface area, good gas-solid contact, accommodation of high gas flow rates with low pressure drop and enhanced heat transfer, can be combined with the incorporation in their structure of suitable redox oxides capable for cyclic redox operation with high reaction heat effects. Tests on such laboratory-scale structures using cobalt oxide as a model redox system are presented, demonstrating its efficient long-term cyclic operation. Properly engineered application-specific, modular thermochemical reactor/heat exchanger concepts are also proposed to enhance the utilization of heat transfer fluid enthalpy.
CH-5:IL06 Ceramic Foams for Energy Related Applications
U.F. VOGT1,2, A. BONK1,2, M. GORBAR1, A. STEINFELD3, A. ZUETTEL1, 1Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Hydrogen & Energy, Dübendorf, Switzerland; 2University of Freiburg, Institute of Earth and Environmental, Department of Crystallography; 3Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
Ceramic foams are used in a broad field of energy related applications. The two topics catalytic H2 diffusion on catalytic coated porous ceramics and thermochemical redox cy-cles based on ceria foams will be presented.
Due to the excellent high temperature- and thermal shock resistance of SiC, a highly porous, Pt coated SiC foam ceramic was investigated for a catalytic hydrogen combustion process. As the combustion of hydrogen does not release exhaust gases like CO, CO2 or NOx, catalytic hydrogen burners can safely be used in-doors. Additionally they assure a very high passive safety standard, as they do not need additional ignition, unlike gas heaters.
Ceria based foams are considered for a solar thermochemical cycle with the target of syn-gas production by splitting H2O and CO2, making use of concentrated solar radiation as the source of high-temperature process heat. This process inherently operates at high temperatures by utilizing the entire solar spectrum, and as such provides a thermodynami-cally favourable path to efficient and clean fuel production. For this two-way driven solar thermochemical redox cycle, thermo-shock resistant ceria-based foams have been devel-oped. Doping by tetravalent metal oxides has been investigated to enhance the oxygen exchange mechanism.
CH-5:IL07 Aerogel Materials for Energy
A. RIGACCI, MINES ParisTech, PERSEE - Centre Procédés, Energies Renouvelables et Systèmes Energétiques CS 10207, Sophia Antipolis Cedex, France
Aerogels are fascinating materials coming from gels synthesized via sol-gel processing. They are nanostructured and highly porous materials with high specific areas. Furthermore they offer a wide range of chemical compositions, from mineral to organic sides as well as organic-inorganic hybrid possibilities.
Because of their high specific surface, they have been initially studied for heterogeneous catalysis but the combination of their structural and chemical characteristics permits to investigate a larger field of potential applications. For example, nowadays, a huge quantity of works is dedicated to silica-based aerogels as brand new promising thermal superinsulators because of their extremely low thermal conductivity.
This situation must not hide that aerogel materials are promising for various other applications, particularly within the field of energy harvesting, storage and conversion. Among others can be set off the studies on aerogels as electrode materials for electrochemical devices like fuel cells and supercapacitors. More recently some new research fields are merging, like clean generation of hydrogen by water-splitting.
This review will present what are these materials and exemplify their applicative potential manly based on the illustrations quoted here-above.
CH-5:L09 Preparation of Catalyst with Architectures Dedicated to Heat and Mass Transfer Limited Processes
L. MOLINA-JOTEL1, 2, F. ROSSIGNOL1, R. FAURE2, C. BERTAIL2, T. CHARTIER1, P. DEL-GALLO2, 1SPCTS Laboratory, UMR CNRS 7315, CEC, Limoges, France; 2Air Liquide, Centre de Recherche Claude Delorme, Jouy en Josas Cedex, France
Key industrial processes may have their performances limited by heat or mass transfer. Such processes, which can be either syngas production processes (like Steam Methane Reforming (SMR) and Pre-Reforming (PR)), or syngas valorization to higher value chemicals (Substitute Natural Gas (SNG) , Methanol To Olefins (MTO), Fisher-Tropsh) are well known for being concerned by such limitations. Until this date, fixed bed processes still use pellet catalysts, often perforated by one or several channels to decrease pressure drops and to create new surfaces. Those issues can be solved either by changing the reactor technology (e. g. shifting from fixed bed to slurry bed) or by changing the catalyst architecture/ microstructure at all scales.
Catalysts proposed in this study are of the same centimeter size as that of standard pellets, but now catalysts are coated onto ceramic honeycombs and metallic foams substrates to take advantages of specific supporting macroscopic architectures. We specifically focus on know-how we developed to obtain homogeneous and adherent coatings. The resulting new catalytic architectures are expected improve mass and heat transfers in reactions in processes with potential applications at industrial scale (pilot unity tests).
CH-5:L10 Porous Clay Ceramic for Environmental Technologies
R. SVINKA, V. SVINKA, L. DABARE, O. LESCINSKIS, Riga Technical University Institute of Silicate Materials, Riga, Latvia
Limeless and limerich illitic clays are investigated with goal to produce highly porous ceramic materials for environmental technologies, ie., for wastewater purification. Porous materials are produced with two technologies: by additive of combustible substances and by slip casting of clay suspension, which contain additive of aluminium paste for pore formation in result of chemical reaction. Sorption ability of materials (pellets with porosity about 30 % or plates with porosity about 50 %) is determined concerning substances with molecular or ionic bond. Sorption ability of such porous materials depends on the type of clays and firing temperature as well as heating rate. The pore size distribution at the nanometers scale and specific surface area of pores is an important characteristic of materials. These two characteristics depend on the grain size distribution in the used raw clays. It was determined that the sorption ability is selective. It is the best with respect to the substances with molecular bond and can reach 100% in case of conformable specific surface area. The irradiation of fired porous materials with accelerated electrons was found to increase the sorption ability.
CH-5:IL11 Porous Wall Hollow Glass Microspheres (PWHGMs)…. A Unique Material with Important Applications in Energy, Environmental Remediation, Security and Medicine
G.G. WICKS, Wicks Consulting Services, LLC, Aiken, SC, USA
A new class of materials, called Porous Wall Hollow Glass Microspheres (PWHGMs), was originally developed for uses in the nuclear community. Since that time, the technology has been further advanced for applications in areas of Energy (ex. Hydrogen storage vehicles, lead acid as well as lithium ion batteries), Environmental Remediation (ex. CO2 sequestration), Security, and Medicine (ex. new drug delivery platforms and improved MRI contrast agents), along with a variety of other potential uses.
The PWHGMs range in size from 2 to 100 microns, are hollow with very thin shells of about 1-2 microns thick, and their most unique characteristic is that porosity is induced and controlled in the outer shells on a scale of 100 to 1,000 Angstroms. This allows the glass micro-balloons to be filled with materials of interest and released, on demand. This one-of-a-kind material, which is patented and recently licensed, was awarded an R&D 100 Award in 2011 and voted “Top Honors” at a Symposium on Discovery and Innovation in 2012.
CH-5:IL12 Ceramics for Filtration
J. ADLER, R. KRIEGEL, U. PETASCH, H. RICHTER, I. VOIGT, M. WEYDT, Fraunhofer IKTS, Dresden/Hermsdorf, Germany
Acc. to the outstanding properties of ceramics as corrosion, wear and temperature stability, as well as high stiffness, a tremendous variety of applications has been developed. Therefore a long list of different materials, structures and shapes exists, reaching from open celled foams for molten metal filtration, candle filters and plugged honeycombs for hot gas particulate filtration, membrane filters for micro-, ultra and nanofiltration of liquids, to nonporous membranes for pervaporation and gas separation.
The presentation gives a short overview about most of these application fields and an update to actual developments.
One of the coarsest structures for separation of frac sand has been reported made of rings of dense silicon carbide. Differently, for all other filtration application, cellular or porous ceramics are needed. Deep bed foam filters are used to filter molten steel, as well as aerosols in exhaust gas. Coarse filters made of fibers or sintered grains are used in hot gas and exhaust gas filtration, often in combination with catalytic means. Very fine porous membranes with micro- and nanometer range pores are used for filtration of liquids like waste water or beverages. Zeolithe and perowskite membranes are under development for pervaporation resp. gas separation.
CH-5:IL13 New Technology with SiC Porous Materials; Progress in the Development of the Diesel Vehicle Technology
K. OHNO, IBIDEN Co. Ltd, Ibi-gun, Gifu Pref., Japan
Over 10 years have passed since the first series production of DPF by IBIDEN. During these years there were some progresses in the technology. The Octagon/Square cell structure technology was developed for higher ash storage and durability is one example. In this structure the inlet cell volume is 1.5 times that of the conventional cell and lifetime of DPF has been prolonged by approximately 1.5 times.
Recently diesel emission regulation has become stringent regarding both PM and NOx worldwide. For passenger car, SCR coated DPF system is considered as one of the promising options for future system by the benefit of downsizing. To integrate the SCR catalyst into DPF, it is necessary to design the DPF so as to have higher porosity compared with the conventional DPF. However it leads to loss of robustness, we formed the oxidation layer on the SiC particle composing DPF so as to improve the strength of DPF substrate.
For heavy duty (HD), PM regulation became tighter and DPF has come to be used. In HD the fuel consumption is emphasized but a demand of robustness is comparatively low. So the effort to realize the low pressure loss substrate has been made with thin wall DPF for future system.
These innovative DPF will be expanded to worldwide following emission gas regulations.
CH-5:L14 Fabrication and Properties of Ceramic Membranes for Oil Filtration
JUNG-HYE EOM, YOUNG-WOOK KIM, Functional Ceramics Laboratory, Department of Materials Science and Engineering, Univeristy of Seoul, Seoul, Republic of Korea; IN-HYUCK SONG, Engineering Ceramic Group, Korea Institute of Materials Science, Changwon, Republic of Korea
Ceramic microfiltration membranes have been fabricated from inexpensive raw materials such as kaolin, talc, bentonite, and carbon black by a simple pressing route. Carbon black was added as a template. Flat disk filters have been obtained by sintering the mixed materials. The prepared ceramic membranes were sintered at 1000 °C. The effect of template content on the porosity, pore size distribution, flexural strength, permeability, and oil rejection rate of the ceramic membranes were investigated. It is observed that with increasing template content, the porosity and permeability of the ceramic membranes increases and the flexural strength and rejection rate of the ceramic membranes decreases. A maximum oil reject rate of 96% was obtained in a ceramic membrane with average pore size and porosity of 0.7 μm and 39%, respectively.
CH-5:L15 New Ultra-divided MgAl2O4-supported Bimetallic Pt-Pd catalyst. Performance Comparison with a Commercial Diesel Oxidation Catalyst (DOC)
S. LE BRAS, F. ROSSIGNOL, Laboratoire de Science des Procédés Céramiques et de Traitements de Surface, UMR CNRS 7315, Centre Européen de la Céramique, Limoges, France; K. LOMBAERT, N. RAOUL, Renault, Centre Technique de Lardy, Lardy, France
Today's challenge for auto exhaust catalysts is not only to meet Euro 6 standards, but also to achieve high catalytic performances and sustainability, using a precious metal content as low as possible. The key is to optimize Metal-Support Interactions (MSIs) promoting a high metallic dispersion and a strong active phase(s) anchorage.
Hence, the support should be made of nanosized crystallites and exhibit a high specific surface area with tailored host sites. Thus, an ultra-divided Magnesium Aluminate Spinel (MAS) support has been synthesized via an aqueous sol-gel derived route. This MAS was then mixed with Pt(NO3)2 and Pd(NO3)2 aqueous solutions according to the Incipient Wetness Impregnation method. These mixtures were treated by conventional heating or microwave irradiation to reach the active form of the metallic phase.
This work aims to compare the stability upon hydrothermal ageing and the catalytic performances of this ultra-divided MgAl2O4-supported bimetallic Pt-Pd catalyst with those of a commercial DOC. H2-chemisorption and Stem-Haadf images reveal the strong mechanical anchorage of the active phase and the high metallic dispersion promoted by the MAS. Besides, an optimized pre-treatment of the MAS-catalyst enable to improve its catalytic activity compared to the DOC's.
CH-5:L16 Characterization of Novel Designed Tialite-based Ceramic Filter for Aftertreatment Application
K. IWASAKI, Sumika Ceramics Poland Sp.zo.o., Wroclaw, Poland
A diesel particulate filter (DPF) is a functional soot-filtration medea for the after-treatment system. Although it it is a powerful device, it also maintains open issues of higher fuel penalty based on high backpressure inside the exhaust pipe and post fuel injection for removing the soot accumulated inside DPF during driving. To reduce post injection frequency, accumulating much amount of soot particles and maintaining the structure stable after soot particles are combusted by fuel injection is highly required. This indicates that higher thermal shock performance called is quite important for DPF. A conceptual DPF with aluminum titanate(AT) material and with hexagonal cell design has recently been presented. The main characteristic of this filter is the lower backpressure based on the larger filtration area. Furthermore. it is shown that the temperature behavior between Square(SQ) and Hexagonal(HEX) design are quite different. HEX shows lower maximum temperature and thermal gradient during regeneration process. there is a strong correlation between filter weight and thermal shock performance, but HEX design was found to be independent of the weight. The main characteristic of HEX is to have two different types of wall, inlet/outlet and inlet/inlet wall.
CH:P01 Fabrication of Meso-Macro Porous b-SiC Body by a Direct Reaction between Carbon Black Powders and Metallic Si
SANG WHAN PARK, GYOUNG-SUN CHO, YUNG-CHUL JO, MI-RAE YOUM, SUNG-IL YUN, Interfacial Control Research Center, Korea institute of Science and Technology, Seoul, Republic of Korea
Recently, importance of the meso-macro porous SiC with high surface area has been increased for the use as catalyst support under harsh conditions such as hydro desulfurization, automotive exhaust-pipe and other application, since meso-macro porous SiC has many excellent properties such as stability at high temperature, resistance to corrosion and high chemical resistance. In this study, meso and macro porous SiC were fabricated by a direct reaction between metallic Si and carbon black. The β -SiC was synthesized by a heat treating preforms of various C/Si mole ratios at the temperature of 1200 ~ 1300 ℃ under vacuum and/or in Ar atmosphere. Meso-macro porous SiC bodys were successfully synthesized by a direct Si-C reaction with additional processes to remove residual Si and C. BET surface area of synthesized meso-macro porous SiC varied from 25 to 70 m2/g depending on the synthesis temperature and C/Si mole ratios of C/Si preform. The compressive strengths of the synthesized meso-macro porous SiC was better than 10 MPa.
CH:P04 Mechanical and Structural Properties of Vitrified Bonded Abrasive Material depending on the Glass Composition
C. DURIF, H.-J. SCHINDLER, T. GRAULE, Empa, Swiss Federal Laboratories for Materials Science and Technology, Duebendorf, Switzerland
An investigation on bonding hard materials such as Corundum with glass phase has been carried out in the field of abrasive materials. The nature of the interfacial cohesion between those two phases is impacting the performances of the tool. The study is an industrial research on the influence of different alumina on elastic, mechanical and structural properties of vitrified bonded abrasive material. Three formulations were produced, one of calcined alumina, one of tabular alumina (cracks nucleation resistant) and one of calcined alumina with 25 wt% of yttria-stabilized zirconia (cracks creation and propagation resistant). For each mixture, porosity measurement, Young's modulus and bending strength, as well as SEM pictures were made to analyse the interfacial cohesion and the microstructural changes. Against all expectations, the addition of stabilized zirconia did not improve the properties of the material, but on the other side the use of tabular alumina was showing more promising results.
The project was founding by CTI: the Commission for Technology and Innovation of Switzerland.
CH:P06 Al2O3 Preforms with Gradient Porosity for Brake Disk Application
A. STROJNY-NEDZA, K. PIETRZAK, M. CHMIELEWSKI, K. JACH, Institute of Electronic Materials Technology, Warsaw, Poland
It has been known for many years that the incorporation of metallic particulates into a ceramic matrix can bring about improvement on ceramic mechanical properties. Alumina/copper composites are well known for their good frictional wear resistance, high resistance to thermal fatigue, high thermal conductivity, high absorption and dissipation of heat. The combination of properties possible in alumina-copper composites make them particularly interesting for wear application, for example in automobile and aerospace.
Present paper reports the development of a new class of alumina-copper functionally graded materials (FGM) offering a technological potential in automotive brake disks application. The subject of the presented paper is the development of the interpenetrating network structure of FGM material. Manufacturing of the graded materials was based on the gas-pressure infiltration of graded porous alumina performs by liquid copper. The graded porous ceramic preforms (from 20 up to 60% porosity) were made by casting of layers from slurries of alumina powder and rice starch powder (pore forming agent), lamination of the layers and subsequent burn-out of the starch and sintering.
CH:P08 High Throughput Separation of Biomolecules with Ni-doped Magnetic Mesoporous Silicas
JEONG HO CHANG, Korea Institute of Ceramic Engineering and Technology, Seoul, Korea
The work reports a simple and facile method to prepare novel magnetic mesoporous silica (MMS) materials with high magnetic strength for the convenient and high throughput detection of histidine-tagged enzymes with Ni-doped surfaces. These materials are designed by the incorporation of high-abundance and homogeneously dispersed iron nanoparticles within the mesopores by thermal hydrogen reduction after the incorporation of ferrous ions and demonstrated the selective enrichment and high-throughput recognition of His-tagged enzymes with multi-point anchoring by selective conjugation between His-tag and Ni ions. Selective His-tagged enzyme enrichment efficiency was compared with nickel-based MMS materials, such as Ni2+-MMS and Ni-MMS, and nickel ion doped silica-coated magnetic nanoparticles (Ni2+-MNPs). The efficiency was calculated to 100 ± 1.93 %, 70.94 ± 1.95 %, and 37.03 ± 5.93 % for Ni2+-MMS, Ni-MMS, and Ni2+-MNPs, respectively. This method enables a high-throughput and advanced systematic approach for the separation and immobilization of proteins which cover a broad spectrum of polyhistidine-tagged proteins.