Synthesis of Zr₂WP₂O₁₂/ZrO₂ Composites with Adjustable Thermal Expansion

Zr₂WP₂O₁₂/ZrO₂ composites were fabricated by solid state reaction with the goal of tailoring the thermal expansion coefficient. XRD, SEM and TMA were used to investigate the composition, microstructure, and thermal expansion behavior of Zr₂WP₂O₁₂/ZrO₂ composites with different mass ratio. Relative densities of all the resulting Zr₂WP₂O₁₂/ZrO₂ samples were also tested by Archimedes' methods. The obtained Zr₂WP₂O₁₂/ZrO₂ composites were comprised of orthorhombic Zr₂WP₂O₁₂ and monoclinic ZrO₂. As the increase of the Zr₂WP₂O₁₂, the relative densities of Zr₂WP₂O₁₂/ZrO₂ ceramic composites increased gradually. The coefficient of thermal expansion of the Zr₂WP₂O₁₂/ZrO₂ composites can be tailored from 4.1 × 10^-6 K^-1 to -3.3 × 10^-6 K^-1 by changing the content of Zr₂WP₂O₁₂. The 2:1 Zr₂WP₂O₁₂/ZrO₂ specimen shows close to zero thermal expansion from 25 to 700°C with an average linear thermal expansion coefficient of -0.09 × 10^-6 K^-1. These adjustable and near zero expansion ceramic composites will have great potential application in many fields.