The Coefficients of Thermal Expansion of La2O3, TaVO5 and Ta16W18O94 Below Room Temperature

Abstract

The coefficients of thermal expansion (CTE) of La2 O3 , TaVO5 and Ta16 W18 O94 were measured in the temperature range 150–300 K for space applications. Hot pressed La2 O3 showed a positive CTE of 8.6 × 10−6 K−1 . Sintered TaVO5 had a positive and extraordinarily large CTE (50 × 10−6 K−1 ), but the CTE was negative (−4.0 × 10−6 K−1 ) in the temperature range 340–380 K. The thermal expansion data suggest a reversible phase transformation near 260 K. The CTE of hot pressed Ta16 W18 O94 was −1.52 × 10−6 K−1 . Sintered Ta16 W18 O94 showed slight hysteresis, but the CTE was about −1.0 × 10−6 K−1 .