Low temperature sintering of BaTiO3 using sodium vapor
PTC thermistors can be fabricated in a simple and cost-effective manner.
Overview
Some semiconducting ferroelectric ceramics exhibit positive temperature coefficient (PTC) thermistor behavior, in which their electrical resistivity increases drastically above the Curie temperature. Materials based on perovskite-type barium titanate (BaTiO₃) are widely used as circuit protection devices under conditions of high temperature or large current surges.
Conventional methods to change originally insulating BaTiO₃ powders to semiconductor require highly reducing atmospheres and high sintering temperatures near 1400 ℃.
This invention proposes a low-temperature and cost-effective fabrication method for BaTiO₃-based semiconducting ceramics using sodium (Na) vapor. Grain size control in ceramic products is also possible upon sintering using the present technique.
As the patent application has not yet been published, technical details—including the application specification—will be disclosed after the conclusion of a technology transfer agreement. Please feel free to contact us for further information.
Fabrication flow of BaTiO3 semiconducting ceramics
Semiconducting and sintering processes at temperatures over 500 ℃ lower than conventional methods.
As the patent application has not yet been published, technical details—including the application specification—will be disclosed after the conclusion of a technology transfer agreement. Please feel free to contact us for further information.
Product Application
・PTC thermistor material (ceramic form)
・Monolithic-type PTC thermistor element
Related Works
[1] Received the 58th (Spring 2025) Annual Meeting Young Scientist Presentation Award of the Japan Society of Applied Physics https://www.jsap.or.jp/young-scientist-presentation-award/recipients58
IP Data
IP No. ： JP2025-028183
Inventor ： HOSONO Akira, YAMADA Takahiro
keyword ： PTC thermistor, BaTiO3, Low temperature, Sodium Na