Isothermal Oxidation Resistance of Zr₃[Al(Si)]₄C₆-Based Composite Ceramics at 1000-1300°C in Air

Abstract

The isothermal oxidation behavior of Zr3[Al(Si)]4C6-ZrB2-ZrC composite ceramics at 1000-1300 °C in air has been investigated. The oxidation kinetics of the composites and generally follows a parabolic law. At the same oxidation temperature and time, the weight gain per unit surface area, oxidation rate constant and oxide thickness of the composites are higher than those of monolithic Zr3[Al(Si)]4C6 ceramic. With the incorporation of ZrB2 and ZrC, the oxidation resistance of the composites becomes poor. The surfaces of the oxide layer have a loose and porous structure, consisting of mainly ZrO2 and little mullite, and there are no dense oxide films preventing the inward diffusion of oxygen element effectively.