Aサイト欠陥La(Sr)CrO_3の熱膨張特性

概要

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Thermal expansion characteristics of A-site deficient Sr-doped lanthanum chromites, La_<1-x>Sr_xCr_<1.01>O_<3-δ> (x=0.02, 0.03, 0.05, 0.10, 0.13, 0.15), have been studied in air and in a reducing atmosphere (log P_<o2>=-16) from room temperature to 1000℃. The phase transition from orthorhombic to rhombohedral, accompanying linear contraction, was respectively observed for samples with x=0.02 to 0.10 both in air and in the reducing atmosphere. The phase transition temperature was found to shift downwards with increase in Sr content. Samples with x=0.10 to 0.15 in air and a sample with x=0.13 in the reducing atmosphere gave expansion coefficients comparable to that of 8 mol% Y_2O_3-stabilized ZrO_2(YSZ). In the reducing atmosphere, the thermal expansion coefficients of the samples with x=0.10 to 0.15 remarkably increased in the vicinity of 1000℃ due to generation of oxygen vacancies.
社団法人日本セラミックス協会の論文
1993-07-01