ZrW2O8-containing composites with near-zero coefficient of thermal expansion fabricated by various methods: Comparison and optimization

Various fabrication methods for producing ZrW2O8-containing composites were developed and evaluated. By adjusting the ratio among the components, those composites attained nearly zero thermal expansion. The resulting samples were measured for the coefficient of thermal expansion (CTE) and Young’s modulus using a Thermomechanical Analyzer (TMA). The microstructure, final density, mechanical strength, and ability to maintain their shape in the sintering process were investigated and compared among the sintered samples fabricated by various methods. One of the fabrication methods, the in-situ reaction of ZrO2, Al2O3 and WO3 with mass ratio 2.61:0.03:1, offers the best attainable final density without any geometric distortion from sintering. The zero CTE of these composites allows them to be utilized as the ceramic substrate of optical fiber Bragg gratings and some components in microelectronics to eliminate thermal stresses due to the thermal gradient or transient temperature change.