Substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 for Less Hygroscopicity and Low Thermal Expansion Properties

In this investigation, ZrxY2-xVxMo3-xO12 (0 <= x <= 1.4) is developed and the effects of the substitutions of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12 on the hygroscopicity and thermal expansion property are investigated. For the smaller substitution content (x <= 0.5), their crystal structures remain orthorhombic, while there is crystal water still in the lattice. The linear coefficients of thermal expansions (CTEs), for x = 0.1, 0.3, 0.5, and 0.7, are about -4.30 x 10(-6), -0.97 x 10(-6), 0.85 x 10(-6), and 0.77 x 10(-6) K-1, respectively, from 476 to 773 K, which means that the linear CTE could be changed linearly with the substitution content of Zr4+/V5+ for Y3+/Mo6+ in Y2Mo3O12. As long as the substitution content reaches x = 1.3/1.4, almost no hygroscopicity and low thermal expansion from room temperature are obtained and are discussed in relation to the crystal structure and microstructure.