Research of Oxidation Resistance of Short Carbon Fiber Reinforced SiC Composite by Hot-pressing

Short carbon fiber reinforced SiC(Csf/SiC) composite was prepared by hot-pressing method.XRD,SEM and isothermal oxidation test were used to study the isothermal oxidation property of Csf/SiC composite.The results show that the oxidation weight loss of the composite is the most at 900℃.The weight loss decreases with the oxidation temperatures rising.Below 900℃,the oxidation weight loss of the composites is caused by the carbon fibers oxidation.Above 1450℃,the composites gain weight.Between 900-1450℃,short carbon fibers on the composite surface are oxidized and the SiC matrix forms a protecting film.The inner short carbon fibers still have the strengthen effect for the oxidation layer and matrix protecting them from oxidation,and the composites have good self-resistance oxidation property.When the composites oxide at 1600℃,the composite surface is destroyed badly and lose the resistance oxidation capacity.