Thermomechanical response of polycrystalline BaZrO{sub 3}

• Published in: Physica. C, Superconductivity Vol. 309; no. 1998
• Main Authors: Goretta, K. C., Park, E. T., Koritala, R. E., Cuber, M. M., Pascual, E. A., Chen, N., de Arellano-Lopez, A. R., Routbort, J. L., Univ. de Sevilla
• Format: Journal Article
• Language: English
• Published: United States 01.01.1998
• Subjects: ACTIVATION ENERGY; CATIONS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CREEP; DEFORMATION; DIFFUSION; GRAIN BOUNDARIES; HEATING; POLYCRYSTALS; SHEAR; STRESSES; SUPERCONDUCTORS; TEMPERATURE RANGE 0400-1000 K; THERMAL EXPANSION
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(98)00588-7

Thermomechanical properties of fine-grained, 96% dense, polycrystalline BaZrO{sub 3} specimens were studied. The average thermal expansion coefficient of BaZrO{sub 3} at 2511000{sup o}C was 7.72x10{sup -6}{sup o}C{sup -1}. At 25{sup o}C, Young's modulus was 240.5 GPa and the shear modulus was 97.2 GPa. These values decreased by {approx}10% with heating to 1015{sup o}C. Poisson's ratio was 0.237 and was independent of temperature. The BaZrO{sub 3} specimens exhibited a thermal expansion coefficient of about one half, and elastic moduli more than twice, those of polycrystalline high-temperature superconductors. Diffusional creep was observed when BaZrO{sub 3} was compressed at 1300-1400{sup o}C; the activation energy for steady-state deformation was 460{+-}30 kJ/mole. The mechanism was probably grain-boundary sliding, controlled by diffusion of one of the cations along grain boundaries. Deformation rates below 1000{sup o}C were too low to relax thermally generated stresses.