Negative Thermal Expansion of (ZrMg)xY2–2xMo3O12 Ceramics with Low Hygroscopicity

Abstract

(ZrMg)xY2–2xMo3O12 (x=0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1) ceramics have been synthesized to obtain less hygroscopicity and negative thermal expansion. With increasing the substitution of (ZrMg)6+ (ion radius 7.2 ×10–11 m) for Y3+ (ion radius 9×10−11 m), the crystal water are reduced obviously. The linear thermal expansion coeffcient is improved with increasing the content of (ZrMg)6+. The material shows near zero thermal expansion (−0.12×10−6 K−1, 430–870 K) with x=0.7. Meanwhile, ZrMgMo3O12 shows low non-hygroscopicity and negative thermal expansion, but low softening temperature. After substituting amount of Y3+ for (ZrMg)6+ in ZrMgMo3O12 (x=0.8), the softening temperature increases remarkably (750 K to 830 K) and it presents near zero thermal expansion.