Microwave Sintering BaTiO₃ Ceramics Using Liquid Phase Sintering

Abstract

Microwave sintering is a process in which target materials absorb microwaves and heat themselves from the inside. When microwave energy is effectively absorbed by the material, energy consumption for the sintering can be reduced. Our study is focused on the microwave sintering of BaTiO3 to more rapidly obtain dense ceramics with specific characteristics. For BaTiO3-based electronic components, the sintering temperature is too high for manufacture, so various additives are used to decrease the sintering temperature without undue worsening of the electrical characteristics. In this work, during microwave sintering, BaCO3, H3BO3, BaB2O4 and LiF were added to form a liquid. The effects of the amount of liquid phase on density and dielectric properties were investigated. BaTiO3 sintered with BaCO3 and H3BO3 showed dielectric properties, whereas BaTiO3 sintered with BaB2O4 had semiconducting properties with PTCR characteristics. Also, LiF-added BaTiO3 indicated a dielectric constant in which the peak shifts to lower temperatures with higher LiF concentrations.

Chemical Interaction Between LiF and MgAl2O4Spinel During Sintering

“…For example, ‡ Na 3 AlF 6 , AlCl 3 , CaCO 3 , and LiF have all been shown to promote sintering in spinel, 16–26 although the detailed mechanisms have remained elusive. LiF has been used to speed up the sintering kinetics of several other systems including SrTiO 3 , 25 BaTiO 3 , 26–30 and MgO 31,32 . LiF is the only compound considered for use as a sintering aid in the production of low porosity, transparent spinel via hot pressing 16,33–36 .…”