Study on the Influence Law of Ce on Microstructure and High-Temperature Oxidation Resistance of Ti-Al-Si Composite Coating

Abstract

High-temperature titanium alloys are widely used in aerospace hot parts; however, the thermal barrier temperature of 600 °C limits its service temperature. In this paper, a two-step hot-dip plating method is proposed to prepare the composite coating containing Ce on the surface of titanium alloy, which can make the oxidation resistance temperature of titanium alloy reach 800 °C The microstructure, phase composition, and element distribution of Ce-containing Ti-Al-Si hot-dip coating, Ce-containing Ti-Al-Si pre-oxidation coating and Ce-containing Ti-Al-Si high-temperature oxidation coating were studied. The results showed that the Ti-Al-Si hot-dip coating containing Ce was mainly composed of (Ti,Ce)(Al,Si)3 alloy phase layer, and the Ti-Al-Si pre-oxidation coating containing Ce was mainly composed of Ti-Al binary system phase layer and dense Al2O3 layer rich in CeO2. Ce in the high-temperature oxidation coating of Ti-Al-Si containing Ce was mainly distributed in Ti3Al, TiAl, TiAl3 + Ti5Si3 mixed phase layer and Al2O3. The addition of Ce could improve the uniformity of composite coating, prevent the spread of cracks, and improve the high-temperature oxidation resistance of Ti-Al-Si coating.