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

Low‐thermal‐expansion porous ceramics are required for numerous applications. This work develops low‐thermal‐expansion porous ceramics by using SiC and ZrW 2 O 8 as positive and negative thermal expansion materials, respectively, bonded by a glassy material. The mixture of SiC, ZrW 2 O 8 , 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 ZrW 2 O 8 , particle size 20–45 μm or 45–90 μm can preserve ZrW 2 O 8 during the sintering process and have a low thermal expansion coefficient. Samples sintered by the conventional method have a high thermal expansion coefficient because ZrW 2 O 8 decomposes to ZrO 2 and WO 3 at the sintering temperature.