Barium-Free Glass-Ceramic Sealants from the System CaO-MgO-B2O3-Al2O3-SiO2 for Application in the SOFC
The planar solid oxide fuel cell (p-SOFC) is a promising configuration of a high-T fuel cell. Barium alumosilicate glass ceramics are suggested to use as sealants by many authors since these materials seem to meet the requirements to establish a hermetic and electrically insulating seal between the steel components of the SOFC. However, in long-term application, the formation of BaCrO4 may degrade the interfacial strength between glass-ceramics and metallic interconnect and disrupt the cell components. In this work, a series of barium-free glass-ceramics in the system of CaO-MgO-B2O3-Al2O3-SiO2 were prepared. The selected compositions were located within the constitutional range of åkermanite – forsterite –anorthite. The thermal properties including glass transition temperature (Tg) and crystallization temperature (Tc) of the produced glasses were measured. The effect of boron oxide additions was studied in order to optimize the softening and flow behavior. For the experiments, a hot – stage microscope was used. Some glass compositions were mixed with high – CTE akermanite powder in order to increase their CTE after sintering. The CTE of the investigated materials after sintering at 900 °C, 2 h, ranged from 10.5 to 11.8 10−6 K−1.
Hyungsun Kim, Jian Feng Yang, Chuleol Hee Han, Somchai Thongtem and Soo Wohn Lee
A. Theerapapvisetpong et al., "Barium-Free Glass-Ceramic Sealants from the System CaO-MgO-B2O3-Al2O3-SiO2 for Application in the SOFC", Materials Science Forum, Vol. 695, pp. 1-4, 2011