Analysis on high-temperature-resistant characteristics of LaCrNiMnO ceramics

摘要

The investigations carried out by extensive stability tests on LaCrO↓(3), NiMn↓（2）O↓（4） and their composite materials have revealed that composite materials are greatly superior to single-phase materials in stability. In this paper, the causes of resistance variation on single phase materials during ageing are analysed applying the defect chemistry theory. The research suggests that the reduction of oxygen vacancies concentrations. which result from the absorbed oxygen in the surface and pores of ceramics diffused gradually into grains, decreases the resistivity of p-type semiconductor ceramics LaCrO↓(3) and increases that of n-type semiconductor ceramics NiMn↓(2)0↓(4). Thus, it is concluded that the excellent high-temperature-resistant characteristics of composite electroceramics are the result of the compensation effect of composite materials. # 1998 Elsevier Science S.A. All rights reserved.