Measurement of Internal Stress in PTC Ceramics

Abstract

The temperature dependence of internal stress in PTC ceramics with various Curie points was successfully measured by a microindentation and a X-ray diffraction techniques. At ferroelectric phase region, the internal stress decreased with approaching to Curie temperature and reached to almost zero at paraelectric phase region. The effects of internal stress on PTC behavior were discussed with potential barrier related to an effective permittivity.