Phase diagram study in the CaO-Cr2O3-La2O3 system in air and under low oxygen pressure

被引：18

作者：

Peck, DH ^{[1
]}

Miller, M ^{[1
]}

Hilpert, K ^{[1
]}

机构：

[1] Forschungszentrum Julich, Res Ctr, Inst Mat & Proc Energy Syst, D-52425 Julich, Germany

来源：

SOLID STATE IONICS | 1999年 / 123卷 / 1-4期

关键词：

CaO-Cr2O3-La2O3; system; phase diagram; calcium doped lanthanum chromate; perovskite; Ruddlesden-Popper phase;

D O I：

10.1016/S0167-2738(99)00087-9

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Phase equilibria were determined in the complete composition range of the CaO-Cr2O3-La2O3 system in air at 1223 K and under low oxygen pressure (high vacuum, p(O-2) approximate to 10(-9) bar). XRD, DTA and electron probe micro analysis of quenched samples were used. The (La, Ca)CrO3 perovskite phase is the only ternary phase stable in air. The Ruddlesden-Popper phases (La, Ca)(n+1)CrnOn+1 (n = 1, 2, 3) were identified in addition to the perovskite phase in the samples annealed under low oxygen pressure, The solubility limit of Ca in the La1-xCaxCrO3 phase was determined in air as x = 0.31 +/- 0.01 at 1223 K and under low oxygen pressure as x = 0.22 +/- 0.02 at 1873 K. In addition, investigations of the pseudo binary CaO-Cr2O3 phase diagram were performed which clarify contradictions in the literature. (C) 1999 Elsevier Science B.V. All rights reserved.

引用

页码：47 / 57

页数：11

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