Thermal Properties and Thermal Shock Resistance of γ-Y2Si2O7

Authors

Ziqi Sun, Chinese Academy of SciencesFollow
Yanchun Zhou, Chinese Academy of Sciences
Jingyang Wang, Chinese Academy of Sciences
Meishuan Li, Chinese Academy of Sciences

RIS ID

41930

Publication Details

Sun, Z., Zhou, Y., Wang, J. & Li, M. (2008). Thermal Properties and Thermal Shock Resistance of γ-Y2Si2O7. Journal of the American Ceramic Society, 91 (8), 2623-2629.

Abstract

Thermal properties, namely, Debye temperature, thermal expansion coefficient, heat capacity, and thermal conductivity of γ-Y₂Si₂O₇, a high-temperature polymorph of yttrium disilicate, were investigated. The anisotropic thermal expansions of γ-Y₂Si₂O₇ powders were examined using high-temperature X-ray diffractometer from 300 to 1373 K and the volumetric thermal expansion coefficient is (6.68±0.35) × 10⁻⁶ K⁻¹. The linear thermal expansion coefficient of polycrystalline γ-Y₂Si₂O₇ determined by push-rod dilatometer is (3.90±0.4) × 10⁻⁶ K⁻¹, being very close to that of silicon nitride and silicon carbide. Besides, γ-Y₂Si₂O₇ displays a low-thermal conductivity, with a κ value measured below 3.0 W·(m·K)⁻¹ at the temperatures above 600 K. The calculated minimum thermal conductivity, κ_min, was 1.35 W·(m·K)⁻¹. The unique combination of low thermal expansion coefficient and low-thermal conductivity of γ-Y₂Si₂O₇ renders it a very competitive candidate material for high temperature structural components and environmental/thermal-barrier coatings. The thermal shock resistance of γ-Y₂Si₂O₇ was estimated by quenching dense materials in water from various temperatures and the critical temperature difference, ΔT_c, was determined to be 300 K.