Development of Low‐Thermal‐Expansion Silicon Carbide/Zirconium Tungstate Porous Ceramics

Abstract

Low‐thermal‐expansion porous ceramics are required for numerous applications. This work develops low‐thermal‐expansion porous ceramics by using SiC and ZrW2O8 as positive and negative thermal expansion materials, respectively, bonded by a glassy material. The mixture of SiC, ZrW2O8, and glassy material was sintered by the conventional method or pulsed electric current sintering (PECS, or sometimes called spark plasma sintering) at 850°C. In samples sintered by PECS with ZrW2O8, particle size 20–45 μm or 45–90 μm can preserve ZrW2O8 during the sintering process and have a low thermal expansion coefficient. Samples sintered by the conventional method have a high thermal expansion coefficient because ZrW2O8 decomposes to ZrO2 and WO3 at the sintering temperature.