Low-temperature fabrication of porous SiC ceramics by preceramic polymer reaction bonding

Preceramic polymer polycarbosilane (PCS) and silicon carbide (SiC) powders were adopted as the starting materials for the fabrication of porous SiC ceramics. During the heat treatment process, PCS experienced an organic-inorganic transformation and acted as the bonding material between SiC particles at a low temperature of 1100 degreesC. The particle size of starting SiC powders and PCS content can control the pore size distribution and porosity. Fracture strength increases with higher content of PCS. Moreover, the as-fabricated porous SiC ceramics exhibit a low average coefficient of thermal expansion (CTE) of 3.4x10(-6)/K from room temperature to 800 degreesC. (C) 2004 Elsevier B.V. All rights reserved.