Superhydrophobicity and in situ barrier: A dual-functional coating for hydration-resistant MgO-CaO refractories

Hydration resistance is a critical performance indicator for MgO-CaO refractories in industrial applications. In this study, a novel anti-hydration strategy was developed through the construction of a composite organic–inorganic coating on MgO-CaO aggregates using a facile impregnation approach. The coating comprises a ZrCl 4 -derived sol, docosanoic acid (DCA, C 22 H 44 O 2 ), and nano-ZrO 2 particles. The modified aggregates exhibited super-hydrophobicity properties, with a water contact angle of 150.47°, which effectively inhibited moisture penetration. Upon heat treatment, the ZrCl 4 -derived sol decomposed and further reacted with CaO to form a dense CaZrO 3 layer, providing long-term hydration resistance. Hydration tests demonstrated exceptional stability, with a weight gain of only 0.025 % after 10 days of exposure to humid environments (at 25 °C and 85 % relative humidity). This work offers a scalable approach to enhance the durability of MgO-CaO refractories by integrating short-term hydrophobicity and long-term ceramic passivation.