CeO2 doped Al2O3 composite ceramic coatings fabricated on γ–TiAl alloys via cathodic plasma electrolytic deposition

Abstract

CeO2 doped Al2O3 composite ceramic coatings were fabricated on TiAl alloys via cathodic plasma electrolytic deposition technique in 0.3 mol/L Al(NO3)3 ethanol electrolytes containing different concentrations of Ce(NO3)4. The effects of CeO2 doping contents on microstructures, elemental compositions, mechanical properties, high temperature oxidation resistance at 850 °C, and wear resistance against GCr15 balls at 200 °C of the coatings were investigated. The results indicated that the contents of CeO2 in composite coatings increased with increasing concentration of Ce(NO3)4, and composite coatings were composed of α–Al2O3 mainly, γ–Al2O3, and a little CeO2. The doping of CeO2 helped to improve the phase inversion from γ–Al2O3 to α–Al2O3. The crystallization and wear resistance of composite coatings increased due to the doping of CeO2. In the electrolyte containing 0.015 mol/L Ce(NO3)4, the coating was the most uniform and compact, and of the best high temperature oxidation resistance and mechanical properties.