Microstructure evolution and corrosion mechanisms of silica refractory in a pure hydrogen atmosphere at high temperature

The safety of hydrogen at high temperatures depends on the lining refractories, however research on their corrosion behavior in a pure hydrogen environment is still in its infancy. In light of their extensive use in high-temperature industries and the potential hydrogen corrosion risk associated with their high SiO₂ content, the corrosion behavior of coke oven silica bricks in a pure hydrogen environment at 1200–1450 °C, along with their macroscopic physical properties, microstructure, and phase evolution, were systematically investigated in this work. The results indicate that higher temperatures and smaller sample sizes accelerated material weight loss. Although corrosion generally degrades mechanical properties, an anomalous relative strength recovery was observed after exposure at 1450°C for 4 h compared with specimens corroded at lower temperatures. Microstructural analysis suggests that this recovery may be associated with the in‑situ formation of SiO₂ fibers via disproportionation reactions, with fiber growth governed by both the “vapor‑liquid‑solid” (VLS) and “vapor‑solid” (VS) mechanisms. By elucidating the corrosion behavior and the relative strength recovery phenomenon, this study provides a theoretical basis for selecting and designing refractory materials for hydrogen service at high temperature.