Microwave sintering PTC thermistor ceramics
Author: langfeng Time: 2020-08-21
Microwave sintering of PTC thermistor ceramics Positive temperature coefficient (PTC) thermistors are characterised by
an increase in the electrical resistance with temperature. They are widely used in various industrial and domestic applications,
such as electronic and electrical temperature control. Chang et al. have studied the orientational growth of grains in doped
BaTiO3 PTCR materials by microwave sintering. It exhibits typical microstructures of sintered sample. The conventional-sintered
sample shows ecliptic spherical shape, whereas the microwave-sintered sample shows an orientational strip-like microstructure.
The growth of grains in microwave-sintered BTO is obvious orientational, which is very different from the familiar
conventional-sintered BTO. The XRD analysis indicates that the perovskite structure of microwave-sintered BTO
is tetragonal, whereas the conventional-sintered sample is cubic. The reason for this abnormal phenomenon can perhaps be
attributed to the polarisation of BTO as a typical piezoelectric material in the microwave field, and also to the enhancement of
grain diffusion by the microwave-sintered.