Effect of Al₂O₃ doping content on CMAS corrosion resistance of Gd₂（Zr_0.7Ce_0.3）₂O₇

The effects of different Al₂O₃ doping levels （mass percent： 5%， 10% and 20%， respectively） on the CMAS （CaO-MgO-Al₂O₃-SiO₂） corrosion behavior of Gd₂（Zr_0.7Ce_0.3）₂O₇ ceramic materials at 1300 ℃ for 10 h were systematically investigated. The corrosion depth， phase composition of corrosion products， and the influence of Al₂O₃ doping on the thermal expansion coefficient were analyzed using X-ray diffraction （XRD）， scanning electron microscopy （SEM） and thermal dilatometry. The results showed that， with increasing Al₂O₃ content， the thickness of the CMAS-induced reaction layer gradually decreased. The doping of Al₂O₃ promoted the formation of a dense apatite phase （Ca₂Gd₈（SiO₄）₆O₂） and a magnesium-aluminum spinel phase （MgAl₂O₄） under high-temperature conditions. Energy-dispersive spectroscopy （EDS） mapping of cross-sectional areas confirmed that these reaction products effectively inhibited the penetration of molten CMAS into the ceramic interior， significantly enhancing the corrosion resistance of the material.