Effect of Al and Cr alloying by arc cladding on the high-temperature oxidation resistance of MoSi2 materials

Abstract

Different proportions of Al and Cr alloying MoSi2 were prepared by arc cladding with different mass fractions of MoSi2, Al, and Cr as raw materials. The work studied the effects about of Al and Cr on the phase, high-temperature oxidation morphology, products, and high-temperature oxidation property of MoSi2. The results confirmed that the volume expansion coefficient of Al2O3 generated by material oxidation was low which could reduce the degree of mismatch and the cracks in the oxide film. Cr element had a poor effect on enhancing the continuity and compactness of the oxide film, however, it could improve the stability of t-MoSi2 formation after arc cladding. MoO3 was not formed in the MoSi2 material added with Al and Cr show the surface oxidation. A dense and continuous Al2O3–SiO2 oxide film was formed, and no cracks holes were found in the oxide film. After oxidation at 800 °C–1200 °C for 120 h, the sample still maintained good oxidation protection. According to the calculation of oxidation kinetics, the MoSi2 material added with Al and Cr had good oxidation resistance. 3% Al + 9% Cr + 88% MoSi2 had the optimal high-temperature oxidation resistance about four times than pure MoSi2.