Corrosion behavior of Fe-containing silicate over ytterbium hafnate ceramics with different HfO2 content

High-temperature molten silicate deposit corrosion has become a critical factor for the failure of thermal barrier coatings. In this work, promising ytterbium hafnate ceramics with different HfO 2 content were prepared by solid-phase reaction, and the effect of HfO 2 content on Fe-containing silicate corrosion behavior of ytterbium hafnate ceramics was investigated. The evolution of HfO 2 content showed negligible influences on reaction products and corrosion mechanism. The attack of Fe-containing silicate melts on the ceramic led to the formation of a reaction layer consisting of apatite, fluorite, and garnet. This layer plays a critical role in preventing further penetration of the melts. However, ytterbium hafnate ceramics with lower HfO 2 content showed better resistance to melt attack.