MICROWAVE PROCESSING OF BATIO{sub}3-BASED PTC THERMISTORS

摘要

Microwave sintering of positive temperature coefficient (PTC) thermistors was carried out in a 2.45 GHz microwave furnace without using any susceptor. Heating behavior, microstructure and electrical properties of the sintered samples were investigated. In the temperature range from 1275°C to 1350°C,optimum density and microstructures were achieved between 1300°C to 1325°C. Samples were also microwave sintered at 1300°C for various soaking times from 10 min to 90 min. It was found that soaking between 30 min to 60 min generated an uniform microstructure. Study also showed that the cooling rate has an influence on PTC effect but not on microstructure. Compared to conventional method, microwave processed samples exhibited better PTC effect.