Analysis on High-temperature-resistant Characteristics of Composite Electroceramics

The investigations carried out by extensive stability tests on LaCrO3, NiMn2O4 and their compositematerials revealed that the composite materials are greatly superior to single-phase materials in stability.The causes of resistance variation on single phase materials during ageing were analysed applying thedefect chemistry theory. The research suggested that the reduction of oxygen vacancies concentrations,which results from that the absorbed oxygen in the surface and pores of cerandcs diffused gradually intograins, decreases the rcsistivity of p-type semic0nductor ceramics LaCrO3 and increases that of n-typesemiconductor ceramics NiMn2O4. Thus it was concluded that the exccedingly good high-temperatureresistant charactcristics of composite clectroceramics are attributed to the compensation effect of compositematerials.