Fabrication of laminated TaCTiC/ TaC-TiC-Graphene composite and investigation of its oxidation resistance

In this study, in order to investigate the graphene effect on the oxidation resistance, at first two laminates TaCTiC/ TaC-TiC-graphene composite was sintered via spark plasma sintering (SPS) at the temperature of 1850 ˚C, for 8 min sintering time,under the pressure of 35 MPa. For investigation the oxidation resistance, the samples were putted in the box furnace at the temperatures of 400, 500, 600 and 700 ˚C for 30 min under the air atmosphere. For oxidation resistance evaluation, X-ray diffraction (XRD), thermal analysis and scanning electron microscopy were applied. It was revealed increasing the temperature resulted to reduce mass of samples which indicates oxidation of Tantalum carbide, Titanium carbide, silicon carbide and graphene. XRD result showed phases such as Ta2O5 and SiO2 formed during oxidation process and the amount of them increases with temperature ascent. The grain growth is negligible up to 600˚C but in higher temperatures, the noticeable growth is occurred. Also, it was disclosed all reactions are exothermic below the 900˚C and at the higher temperature are endothermic and occurred in one step.