Residual Amount of BaCO3 on Glass Thermal Property Based on BaO-CaO-Al2O3-B2O3-SiO2 System

A BaO-CaO-Al2O3-B2O3-SiO2 system for the sealing glass in intermediate temperature solid oxide fuel cell (IT-SOFC) was prepared. The effects of three fusion processes (heating at 1300 degrees C for 1 h, heating at 1400 degrees C for 1 h, and heating at 1400V for 3 h) were explored with focus on the residual amount of BaCO3 and the thermal properties of the glasses by thermal-thermogravimetric analysis (DTA-TG). Samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and thermal expansion coefficient meter. The results showed that 59wt% BaCO3 retained undecomposed in the glass prepared via heat treatment at 1300 degrees C for 1 h and its expansion coefficient decreased due to devitrification of monoclinic BaAl2Si2O8. Softening temperature (>800 degrees C) of the glass produced via heating at 1400 degrees C for 3 h increased obviously owing to the increment of Al2O3 amount. The expansion coefficient of the glass produced via heat treatment at 1400 degrees C for 1 h was 10.3 x10(-6)K(-1) from room temperature to the glass transition temperature, indiating the process of heat treatment at 1400 degrees C for 1 h the optimal condition in three candidates for the specific formula, which was found to be eligible for SOFC sealing.