Thermal cycling and reactivity of a MoSi2/ZrO2 composite designed for self-healing thermal barrier coatings

Consolidated (relative density of 84%) composite made of molybdenum di-silicide (MoSi2) particles dispersed in a yttria partially stabilized zirconia matrix (8Y2O3–Zr02) was prepared by spark plasma sintering. Cyclic oxidation of the composite at temperature ranging from 1000°C to 1300°C was studied. Parabolic rate constants (kp) values of the composite material are in good agreement with those obtained in the literature for the oxidation of bulk MoSi2. Following oxidation exposure, formation of Mo5Si3, SiO2 and ZrSiO4 phases was observed. These observations are compatible with the use of MoSi2 as a self-healing agent in YPSZ thermal barrier coatings. [Display omitted] •Consolidated composite made of MoSi2 particles dispersed in a yttria partially stabilized ZrO2 matrix has been prepared by SPS.•Cyclic oxidation behavior under dry air of the composite has been investigated.•MoSi2 oxidation results in the formation of silica that reacts with the YPSZ matrix to form zircon.•Oxidation rate constant values of the composite were determined at four temperatures.•Zircon is observed far away from the MoSi2 particles and this can be very beneficial for the self-healing mechanism of the composite.