Investigation about the reason of limited grain growth of Y-doped barium zirconate

Abstract Yttrium-doped Barium Zirconate is a protonic conductor that shows excellent chemical stability but low sinterability, demanding high sintering temperatures to achieve appropriate densification. However, even after sintering at high temperature, the grain size remains small, resulting in a low electrical conductivity due to the high grain boundary area. This behavior, according to literature, is associated with the high refractoriness. The first contribution of this work is the establishment of a suitable method to prepare the powder, following the fundamentals of conventional ceramic process, that allowed obtaining BZY20 samples with 98% of theoretical density after sintering at 1600⁰C without sintering aid. The second contribution of this paper is to understand the parameters that limit the grain growth of BZY20, since high grain boundary area compromises the electrical conductivity. This understanding was constructed from SEM microstructure analysis associated with EDS of sintered samples.