High-Temperature Antioxidation Protection and Mechanism of Ti3AlC2-Glass-Ceramic Coating on Titanium Alloy
In order to enhance the high-temperature antioxidation protection effect provided by glass coating on titanium alloy,Ti3AlC2 reinforcing phase was introduced into pure glass coating slurry by ball milling method,the slurry was scraped onto the surface of TC4 alloys,and the antioxidant test was conducted.The results show that when 5%(wt%)Ti3AlC2(TAC5 coating)is added,the thickness of α-contamination layer of the TC4 alloy substrate is minimized,measuring approximately 65.78 μm.In comparison to the pure glass coating under similar test condition,the thickness of α-contamination layer of the TAC5 coating is reduced by about one quarter.The Gibbs free energy of the reaction of Ti3AlC2 with O2 from 1100 K to 1300 K is negative.Combined with BSE,XRD,Raman and TG tests,the results show that Ti3AlC2 reacts with the oxygen infiltrated into the coating to preferentially generate Al2O3 and TiC2,which reduces the contact between the substrate and the oxygen and improves the high-temperature antioxidation protection of the coating.In the meantime,the surface and interior of the coating develop micropores due to the CO2 gas produced by the oxidation of Ti3AlC2.