SiC涂层/三维碳纤维编织体的氧化动力学和机理研究

采用原位反应法在三维碳纤维编织体(简称:RB)的纤维表面制得SiC涂层,通过 XRD、SEM、等温氧化失重和非等温热重分析等测试手段研究了制备方法对SiC涂层均匀性 的影响,并对SiC涂层／碳纤维编织体(简称:CB)材料在等温和非等温条件下,氧化反应的 动力学和反应机理进行了研究.结果表明:SiC涂层均匀、完整地涂覆于编织体内外各纤维表 面;材料等温氧化反应的机理为第一阶段反应控制,第二阶段扩散和反应共同控制;材料的非 等温氧化过程呈现自催化特征,氧化机理为随机成核,氧化动力学参数为:lgA=9.615min^-1; E_a=201.73kJ·mol^-1.

Oxidation Kinetics and Mechanism of SiC Coating/3-dimensional Carbon Fiber Braid

The in situ reaction method was used to prepare SiC coating on 3-D carbon fiber braid (RB). XRD, SEM, isothermal oxidation-weight loss and non-isothermal TG were used to study the oxidation process and oxidation reaction mechanism of SiC coating/3-D carbon fiber braid (CB). The results showed that coating was coated symmetrically and combined well with every fiber of braid. The oxidation process of CB in isothermal condition was reaction-controlled in the first step, gas diffusion and reaction-controlled in the second step. The oxidation process of CB in non-isothermal condition exhibited a self-catalytic characteristic, the oxidation mechanism was random nucleation, the kinetic parameters were: lgA=10.299min-1; Ea=156.29kJ.mol-1.