High-temperature Oxidation Properties of TiC-reinforced Mo Matrix Composites with Cr Element Added

Abstract

This work studied Mo-TiC-xCr (x = 0.0, 0.5, 1.0 wt.%) matrix composites with different component gradients prepared by Spark Plasma Sintering (SPS). The high-temperature oxidation test was conducted at 1200 ℃ in the atmosphere to study the influence of Cr on the high-temperature oxidation behavior of TiC-reinforced Mo matrix composites. The phase composition and morphology of the oxide film were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), and the goal was to determine the effect of the Cr content on the high-temperature oxidation properties of the Mo-TiC-xCr (x = 0.0, 0.5, 1.0 wt.%) matrix composites. The results showed that with increasing oxidation time, the oxide film on the surface of Mo alloy will crack and fall off easily, and the porosity gradually increases. Oxygen underwent vigorous oxidation through the pores and the inside of the matrix, and a protective MoO₂ internal oxide film disappeared. With increasing Cr content, the high-temperature oxidation performance of the Mo alloy improved, the thickness of the oxide film decreased, warping of the surface oxide film was inhibited, the porosity decreased, and volatilization of MoO₃ was inhibited. After oxidation, the surface oxide film was mainly composed of TiO₂, MoO₃, Cr₂O₃ and Cr₂(MoO₄)₃ phases. The TiC particles dispersed in the matrix were oxidized to TiO₂ to inhibit the oxidation of the alloy. The Cr formed a protective oxidation film of Cr₂O₃, which effectively reduced the porosity and delayed the volatilization of the MoO₃, thus improving its oxidation performance.