The Effect of Reoxidation on Thermal Shock Resistance of SrTiO3-Based Varistors
The fabrication processes of SrTiO3-based varistors were investigated to obtain highly thermal-shock-resistant devices. It has been found that the reoxidation conditions are strongly related to the thermal cracking ratio (%) of the varistors. A large compressive stress was generated on the varistor surface by reoxidation, consequent upon the lattice parameter difference between its surface portion and its internal portion. This residual stress on the surface is thought to be the key factor of the achieved thermal-shock-resistance.
Tadashi Takenaka, Hajime Haneda, Kazumi Kato, Masasuke Takata and Kazuo Shinozaki
A. Hitomi et al., "The Effect of Reoxidation on Thermal Shock Resistance of SrTiO3-Based Varistors", Key Engineering Materials, Vols. 421-422, pp. 529-532, 2010