Effect of HfO2 on the compatibility of borosilicate sealing glasses for solid oxide fuel cells application

Abstract

The interfacial reaction between sealing glasses and Cr-containing interconnects presents a challenge for the development of Solid Oxide Fuel Cells (SOFCs). In this paper, attention was focused on the relationship between the glass structure of HfO₂-containing borosilicate glasses and interfacial reaction between glasses and Crofer 22 APU. The results show that HfO₂ dissolves in the glass network with the form of Q² species and condenses the glass structure of borosilicate glasses. In addition, the fraction of Cr⁶⁺ in reaction couples between Cr₂O₃ and glass powders decreases with increasing HfO₂ content from 2 to 8 mol%. Moreover, the thickness of reaction zone is about 1 μm for glass with 2 mol% HfO₂/Crofer 22 APU, while no obvious reaction zone can be observed in glass with 8 mol% HfO₂/Crofer 22 APU. The reported results support the suitability of the prepared glass-ceramics as sealing materials for SOFCs applications.