Oxidation behavior at high temperature of argon arc-surfacing layers on titanium substrate after pre-deposited with pure silicon powders

The surfacing layers with Ti₅Si₃ phase were prepared on the pure titanium substrate by argon arc-surfacing after pre-deposited with pure silicon powders. And the cyclic oxidation test was carried out at 800℃ and 900℃ for samples of the substrate and the surfacing layers. The test results showed that high temperature oxidation performance of the surfacing layers with different microstructures was obviously higher than that of the pure titanium substrate. When the oxidation test temperature is below the solid transformation point, the oxidation performance of the surfacing layers was improved in the order of hypoeutectic, eutectic and hypereutectic microstructures. But if the oxidation test temperature was 900℃, the order of the oxidation performance of the surfacing layers with three types of microstructures was inverse. The main reasons were that solid transformation stress was accumulated by repeatedly heating cooling and the thermal stress because of the difference of the linear expansion coefficients between titanium solid solution and Ti₅Si₃ phases, which resulted in internal cracks in the layers and large oxidized area.