ZrW208/NiWO4 composite ceramics with controlled coefficient of thermal expansion were fabricated by a spark plasma sintering (SPS) method combined with a solgel process. The NiWO4 powder having positive thermal expansion was prepared by using a sol-gel process with tungsten (VI) chloride and nickel nitrate 6-hydrate as raw materials and ethanol and 2-butyl alcohol as solvents. A ZrW2O8 powder having negative thermal expansion was also prepared by using a sol-gel process with tungsten (VI) chloride and zirconium chloride oxide 8-hydrate as raw materials and ethanol and 2-butyl alcohol as solvents. ZrW2O8/NiWO4 composite ceramics without impurity phases were synthesized at 600t in Ar atmosphere. The thermal expansion coefficient of the ceramics could be controlled in the range from 8.95 × 10-6 to-9.15 × 10-6 [K -1] by changing the compositional ratio of ZrW2O8 and NiWO4.
