Protection of titanium alloy components against high temperature corrosion

Abstract

The current paper presents the oxidation characteristics of titanium alloy, Ti–5.8Al–4.06Sn–3.61Zr–0.7Nb–0.54 Mo at different elevated temperatures. The degradation of the alloy under oxidizing conditions is described in detail. The behaviour of the titanium alloy under various hot corrosion conditions and the mechanism involved in degrading the alloy are explained. It is stressed that the application of a high performance coating is extremely necessary in order to use the titanium alloy safely for gas turbine engine applications. Efforts were made to develop high performance coatings for titanium alloy, Ti–5.8Al–4.06Sn–3.61Zr–0.7Nb–0.54 Mo to protect from high temperature corrosion as well as α-case formation. The developed coating exhibited outstanding performance with negligible weight gain and absence of α-case formation during the entire exposure period. It was shown that the formation of a continuous, protective and adherent alumina scale on the surface of coating upon exposure to elevated temperatures is the reason for exhibiting excellent performance.