Orientation-controlled molten silicate/crystalline ceramic interfacial degradation

Molten silicate – crystalline ceramic interfacial degradation is a critical process governing material reliability in high-temperature environments. At elevated temperatures, silicate deposits originating from natural particulates melt to form Ca–Mg–Al–Si–O–rich liquids that interact strongly with crystalline ceramic surfaces. Because such degradation is fundamentally controlled by interfacial processes, crystallographic orientation is expected to play a decisive role in regulating wetting and corrosion behavior, yet this effect has not been systematically resolved. Here, we investigate the orientation-dependent wetting and long-term corrosion behavior of 14 diverse molten silicate systems on crystalline ceramic substrates using YSZ single crystals with (100), (110), and (111) orientations as a model system. Pronounced wetting anisotropy is observed, with melt spreading following the order (100) < (111) < (110), driven by orientation-specific Y-dissolution and consistent with interfacial interaction energies calculated via molecular dynamics simulations. In contrast, long-term corrosion exhibits a distinct crystallographic dependence, indicating a decoupling between wetting and penetration behavior. These findings establish crystal orientation as a governing parameter in molten silicate–crystalline ceramic interfacial degradation and provide a mechanistic basis for understanding and mitigating high-temperature silicate-induced damage across diverse ceramic systems.