Porosity dependence of molten sand wetting and infiltration in oxide ceramics

The role of porosity in governing the interaction between molten sand and oxide substrates remains poorly understood. Here, we systematically investigate the effect of porosity on CMAS wettability, infiltration, and reactivity across 3 mol.% yttria stabilized zirconia (3YSZ), Gd₂O₃, and (Y_1/2Yb_1/2)₂Si₂O₇ (YYbDS) by coupling high temperature contact angle experiments conducted at 1260 °C for 30 min with microscopy, elemental, and phase analyses. In 3YSZ, increased porosity promoted deeper infiltration but suppressed lateral spreading. Gd₂O₃ showed the opposite trend in that greater porosity enhanced CMAS spreading that was attributed to its reactivity. For YYbDS, despite being chemically reactive, showed reduced spreading with increased porosity. Linear regression revealed strong correlations between porosity and a few wetting parameters depending on the reactivity regime. These findings reveal that porosity dependence on CMAS interactions with a substrate are coupled with reactivity and provide an approach to forecast CMAS behavior with novel materials.