Oxidation fronts and oxide scale growth modeling in spark plasma sintered ZrC ultra-high temperature ceramic

Zirconium carbide (ZrC) is a candidate material for extreme environments due to its exceptional thermal and mechanical properties. However, its oxidation behavior, particularly the formation of the Zr–C–O layer, requires further clarification. In this study, we investigated the oxidation of spark plasma sintered ZrC under varying temperatures and oxygen partial pressures, revealing a double-layer oxide scale. At the interface between ZrC and the Zr–C–O layer, we identified previously unreported oxidation front stripes composed of cubic zirconia, along which elliptical submicropores formed, suggesting preferential CO₂ release pathways. The Zr–C–O layer itself was significantly enriched with amorphous free carbon. Based on these findings, we developed a phenomenological model that incorporated the formation of the compact Zr–C–O layer to predict oxide scale growth. This multiscale approach provides new insights into ZrC oxidation mechanisms and supports the design of oxidation-resistant ceramics for aerospace and nuclear applications.