Influence of oxidation inhibitor on carbon-carbon composites: 2. Mechanical behaviors at high temperature

PAN-based carbon fibers impregnated with phenolic resins used as a precursor of carbonized matrix was modified by addition of molybdenum disilicide (MoSi₂) in different concentrations, i.e., 0, 4, 12 and 20% by weight. These composites were unidirectionally manufactured by prepreg mathod, and were submitted to carbonization (heat treated to 1100 °C) and graphitization (to 2300 °C), throughout one step manufacturing process. In this work, the influence of MoSi₂ concentrations having physical properties of oxidation inhibition and brittle-to-ductile transition (BDT) at higher temperatures was investigated in newly developed methods on flexural strength (σ_f), flexural modulus (E_b), and interlaminar shear strength (ILSS) of the composites measured at 1000 °C. As a result, the presence of MoSi₂ in carbon/ carbon composites effectively increased the toughness and the degree of adhesion at interfaces between carbon fibers and resin matrix.