Thermomechanical response of polycrystalline BaZrO sub(3)

• Published in: Physica. C, Superconductivity Vol. 309; no. 3-4; pp. 245 - 250
• Main Authors: Goretta, K C, Park, E T, Koritala, R E, Cuber, M M, Pascual, E A, Chen, Nan, de Arellano-Lopez, A R, Routbort, J L
• Format: Journal Article
• Language: English
• Published: 20.12.1998
• ISSN: 0921-4534

Thermomechanical properties of fine-grained, 96% dense, polycrystalline BaZrO sub(3) specimens were studied. The average thermal expansion coefficient of BaZrO sub(3) at 25-1000 degree C was 7.72x10 super(-6) degree C super(-1). At 25 degree C, Young's modulus was 240.5 GPa and the shear modulus was 97.2 GPa. These values decreased by approximately 10% with heating to 1015 degree 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 degree C; the activation energy for steady-state deformation was 460 plus or minus 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 degree C were too low to relax thermally generated stresses.