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The effect of calendering of alumina loaded preceramic papers in a hard nip laboratory calender at various temperatures, line loads and times of nip passes on their green and sintered properties was investigated. The main objective was to achieve a maximum densification, which resulted in a maximum reduction of thickness of 45%, a green density of 80.5% of the theoretical density and a sintered density of 81% of the theoretical density. The ring-on-ring flexural strength of sintered specimen could be increased from 71±11MPa to 138±33MPa. The surface roughness of green samples could be diminished to a value for R a of below 2µm compared to an R a of 13.2µm for an uncalendered paper, whereas the R a value of the sintered samples was much higher due to the burn-off of the cellulose fibers. Preceramic papers manufactured by the dynamic hand-sheet-forming process exhibit a fiber-orientation which causes anisotropic effects regarding the sintering shrinkage, the surface roughness and Young's modulus. [ABSTRACT FROM AUTHOR]

Abstract: Platinum/aluminum oxide (Pt/Al2O3) catalyst powders were successfully fabricated to give paper-like composites using ceramic fibers by a papermaking technique. As-prepared composites, called paper-structured catalysts, possessed a fiber-network microstructure on which the Pt/Al2O3 powders were scattered. The paper-structured catalysts were subjected to a catalytic reduction process of nitrogen oxides (), and demonstrated a higher performance than the original Pt/Al2O3 powders and a commercial honeycomb catalyst. A simple mixture of catalyst powders and inorganic fibers was not effective, suggesting that the characteristic porous microstructure (average pore size: ca. porosity: ca. 70%) in the paper-structured catalyst possibly contributed to the efficient reduction. Besides, the paper-structured catalyst exhibited a quick response in the catalytic reduction at a rapidly increasing reaction temperature as compared to the honeycomb catalyst. The paper composite is flexible, lightweight and easy to handle; thus the paper-structured catalyst is expected to be a promising catalytic material for exhaust gas purification. [Copyright &y& Elsevier]