Evolved gas analysis during sintering of barium titanate

Abstract

The gases evolved during the sintering of BaTiO 3 have been examined with a combined dilatometer and mass spectrometer (CDMS) apparatus. The CDMS acquires multiple mass/ charge ratios in real time while simultaneously recording dilatometry data. To identify the chemical composition of the numerous recorded mass/charge ratios, cracking patterns, isotopic abundances and decomposition reactions from model compounds (BaCO 3 , BaSO 4 ) were used. Three primary regions of gas evolution were identified. During the heating ramp and into the hold period at 1350°C, CO 2 appears, and below approximately 500°C, this may arise from adsorbed or surface CO 2 . Sulphur dioxide was also observed, and its evolution occurred directly after the majority of the CO 2 appeared and immediately preceded the onset of sintering. Above 1200°C, CO 2 is the primary species observed in the gas phase. The implications of the high temperature chemistry on sintering and on microstructural development are discussed.

Exceptional reliability of MLCCs enabled by defect‐engineered BaTiO3

“…As reported by Lombardo, 18 the BaCO 3 and BaSO 4 , as most common impurities in BaTiO 3 , are decomposed and release CO 2 and SO 2 during sintering, thus reducing the density of ceramics. However, the decomposition temperature of BaSO 4 , arising from the raw material BaS synthesized for BaCO 3 , is higher than 1300 • C, the firing temperature of MLCC devices.…”