EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Hierarchical porous materials are attractive structures for a variety of applications due to their enhanced mechanical efficiency and their high surface area with minimum permeability loss. Nature showcases remarkable examples of hierarchical porous materials that benefit from such unusual set of properties, including bamboo, bone, marine sponges and wood. However, synthetic porous materials...

Colloidal processing has been widely used in the manufacture of ceramics and composites because it allows the design of complex shaped parts and a suitable control of microstructure with cost-effective methods and increased reliability. Although ceramic oxides have been largely studied and produced from the basis of focused studies on colloidal stability and shaping performance of aqueous...

Texture in ceramics can enhance their functional and structural properties. In porous bodies, it may be used for applications as implants, batteries, filters, etc; in dense bodies, for turbine, shielding, etc. Current methods for texturation in dense ceramics employ plate-like particles or microplatelets as starting powders and processes that drive their orientation in specific directions,...

Little is known about how colloidal processing methods affect the microstructural features and, in turn, mechanical properties of transparent yttrium oxide. In this work, commercial nano-Y2O3 was considered and shaped by consolidating yttria-ethanol suspension using conventional slip casting and pressure filtration at various applied pressures. The samples were densified by pre-sintering in...

Pure tungsten carbide nano-powder can be densified in less than 10 s by Electrical Resistance Sintering (ERS) technology under high current and low voltage which activate an ultra-fast Joule heating. The triggering of the flash-like phenomenon in the metal-like conductor is shown to be concurrent with a non-linear reduction of the green compact resistivity. This work investigates the...

Along ceramic processing cycle, it is well known that even a small change of the powders surface energy can cause a considerable effect on the final properties. The processing steps which are most affected by the change of surface energy are powder synthesis, shaping (especially wet methods), and sintering.

A fundamental issue is to enhance densification process using...

Cold sintering is a relatively new process useful to consolidate ceramic-based systems at relatively low temperature (usually below 300°C) under pressure and in the presence of a solvent. Cold sintering has therefore a great potential as an innovative process, enabling the consolidation in a single step of organic materials in an inorganic matrix.
In the present work, natural source-derived...

Zircon (ZrSiO4) is a ceramic material whose properties make it especially interesting to be applied in thermal and environmental barrier coatings at a competitive cost. However, its decomposition at high temperature during the deposition step has so far limited its use by plasma spraying from powder feedstocks.

The aim of the present work is to assess the potential of using suspensions...

Structurally and functionally optimized ceramic materials can revolutionize many applications that rely on biocatalytic reactions. In general, the design of these materials is based on anchoring of biocatalyst phases within randomly porous ceramic supports with huge surface area within as small as possible volume. Nevertheless, the real-world applications require to address the issues related...

The manufacturing of ideal implants requires fabrication processes enabling an adjustment of the shape, porosity and pore sizes to the patient-specific defect. To meet these criteria novel porous hydroxyapatite (HAp) implants were manufactured by combining ceramic injection molding (CIM) with sacrificial templating. Varied amounts (Φ = 0–40 Vol%) of spherical pore formers with a
size of 20 µm...

The fabrication of advanced ceramic matrix composites (CMCs) with low dimensional phases such as carbon nanotubes or graphene is currently an open research topic because their potentiality as reinforcement phases for tougher ceramics. Despite several decades of research, some common experimental issues, such as the homogeneity of the dispersion, their location within the ceramic matrix, and...

Nacre-like ceramic composites are of importance in a wide range of applications, because of their mechanical properties, combining high mechanical strength and high fracture toughness. This unusual combination of properties comes from its structure formed by strongly aligned platelets glued in a matrix. To obtain such a ‘brick-and-mortar’ structure in ceramic composites, different processing...

Zinc oxide is a widely applied ceramic for electronics due to its semiconductor properties. An example is the ZnO varistor which possesses a non-ohmic conductivity over several orders of magnitude. ZnO varistors are usually made with Sb2O3 and Bi2O3 as sintering aids. In addition, oxides of Cr, Mn and Co, for example, are included as dopants, and a complex microstructure with several...

Fused filament fabrication enables the production of ceramic, metallic and multimaterial components with complex geometries. The parts are generated by the selective extrusion of thermoplastic filaments highly filled with powder. Following, the polymers are removed and the parts finally sintered. Each step of the process has a strong influence on the final properties. Here, the influence of...

While lithographic additive manufacturing (AM) of oxide ceramics is starting to become well established, the use of non-oxide ceramics for this particular printing approach is still less matured. One main reason for that is the higher light absorption that non-oxide ceramic powders often have due to their coloration.
This contribution focuses on the advances concerning AM of aluminum nitride,...

Heterogeneous catalysts are used under increasingly harsh conditions, requiring the use of high-performance ceramics with high thermal and chemical stability as carrier material. In addition, a high surface area for an effective reaction at the active sites and well tailored macroporous structures for high product flow are required. Currently, conventional ceramic processes are highly limited...

Aluminum nitride is a highly suitable material for thermal management applications due to its excellent thermal conductivity in combination with promising mechanical properties. However, owing to its tendency towards hydrolytic decomposition and the effect of oxygen impurities on its performance, the selection of shaping and processing methods typically employed is limited, resulting in rather...

3D printing of lightweight mullite honeycomb structures could be successfully demonstrated by the FDM (Fused Deposition Modeling) technique. To achieve 3:2 mullite from preceramic polymers, continuous ceramic filaments containing an alumi-na powder, a polysiloxane polymer and EVA (Ethylene vinyl acetate) as a thermo-plastic component with a diameter of 1.75 mm were made. A temperature above...

Within the framework of the development of ceramic based on mixed composition (Al2O3 - mullite), the formulation of the raw materials involves the kaolinite Al2Si2O5(OH)4 (phyllosilicate) as a source of silicon. Natural kaolinite generally crystallizes in the form of pseudo-hexagonal platelets of small thickness (from 1 µm to 100 nm). The shape of these grains, composed of stacks of several...

The unique combination of foaming gas and freezing ice during the Freeze Foaming (developed by Fraunhofer Institute for Ceramic Technologies and Systems) of biocompatible materials results in a hierarchical porous structure consisting of macro-structural foam cells and micro-structural porous struts. Porous calcium phosphate ceramics are highly suitable as bone substitute materials due to...

Porous $\alpha$-Al$_2$O$_3$ monoliths and membranes were prepared using a novel synthesis approach. Compared to the conventional method of applying carcinogenic epoxides for the initiation of gelation, our synthesis technique is based on gelation by means of cross hydrolysis, thus, rendering the use of carcinogenic epoxides redundant. In this respect, a mutual hydrolysis between the aluminum...

Zircon, or zirconium silicate (ZrSiO4), is a ceramic material widely known for its excellent thermal properties, such as low thermal conductivity and high resistance to thermal shock. This makes it an ideal material for obtaining coatings used as thermal barriers and other structural applications.

In this work, dense zircon complex shape parts have been obtained by means of polysaccharides...

Nanoporous perovskite solid solutions are versatile materials and well suited for the use in catalytical applications, due to their large surface and thus higher reactive area [1,2]. The combination of high surface areas and the use of electric fields provide an adequate tool to further improve the properties required for catalysis by controlling defect formation and mobility. It has been...