Glass–alumina composite coatings for high temperature corrosion protection. Part I: Effect of crystallization and interfacial reaction on the thermo-physical properties

The effect of crystallization and interfacial reaction on the thermo-physical properties of glass–alumina composites, which show good prospects for use as coating materials for high-temperature corrosion protection, has been investigated by using post-annealing processes at 850 °C. Zirconolite precipitated from the glass matrix and the alumina inclusions were steadily transformed into gahnite and feldspar by interfacial reactions. This phase evolution resulted in an overall decrease in strength, Youngʹs modulus, Vickers hardness and thermal expansion coefficient while increasing the indentation toughness. The composites became more refractory and thus better prospects for use in high temperature applications.