THE SYSTEM CAO-CACR2O4-CAAL2O4 IN AIR AND UNDER MILDLY REDUCING CONDITIONS

被引：36

作者：

KAISER, A

SOMMER, B

WOERMANN, E

机构：

[1] Institut für Kristallographie, Rheinisch Westfälische Technische Hochschule Aachen, Aachen

来源：

JOURNAL OF THE AMERICAN CERAMIC SOCIETY | 1992年 / 75卷 / 06期

关键词：

CALCIUM; ALUMINUM; CHROMIUM; OXIDES; CHROMATES;

D O I：

10.1111/j.1151-2916.1992.tb04211.x

中图分类号：

TQ174 [陶瓷工业]; TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

The system CaO-chromium oxide in air is reinvestigated and the existence of intermediate phases with chromium in oxidation states >3+ (Ca5Cr3O12, Ca3(CrO4)2, and Ca5(CrO4)3) confirmed. Under reducing conditions these phases are unstable. A metastable, polymorphic form of calcium chromite, delta-CaCr2O4, is observed. In the CaO-rich section of the CaO-Al2O3-Cr2O3 system a ternary intermediate phase, chrome-hauyne, Ca4[(Al,Cr3+)6O12](Cr6+O4), coexists with calcium chromate and calcium aluminate phases. In air, low melting temperatures are preserved in all assemblages containing calcium chromate phases. Under reducing conditions a new ternary phase, Ca6Al4Cr2O15, coexists with CaO, CaCr2O4, chrome-hauyne, and calcium aluminate phases. The influence of chromium oxide additions on the solidus temperatures of the CaO-Al2O3 system is insignificant.

引用

页码：1463 / 1471

页数：9