Effect of MoO₃ on mechanical interfacial behavior and anti-oxidation of carbon fibers-reinforced composites

In this study, the effect of MoO₃ content on the mechanical interfacial properties and the anti-oxidation behaviors of carbon-carbon (C/C) composites were investigated. The MoO₃ content was varied to 0, 5, 10, 20, and 30wt% of the resin matrix. These composites were prepared by a one-direction filament winding method, and were subjected to carbonization (heat-treatment at 1100°C). As a result, the anti-oxidation behavior and mechanical interfacial properties improved with increasing MoO₃ content at respective heat-treatment temperatures. This is because MoO₃ penetrated the composites through the cracks or pores formed during the manufacturing of the C/C composites and preferentially reacted with oxygen, thereby decreasing the rate of oxidation. This disturbed the carbon active species in the composites, increasing the physical cohesion between the interfaces of the carbon fibers and matrices, and improving thermal stability.