O-SiC_P/Fe界面化学稳定性

Study on the chemical compatibility of O-SiC_P/Fe

SiC颗粒在静态空气气氛中经 12 0 0℃× 10h钝化氧化处理后在表面形成厚约 0 .6 μm ,具有晶态的 β 方石英结构的致密氧化膜。经在氢气气氛 ,115 0℃× 1h高温处理 ,3SiCP/Fe界面反应形成以Fe3 Si,颗粒状石墨和Fe3 C为主的反应产物。Fe3 Si和颗粒状石墨构成反应区 ,Fe3 C在金属基体晶界形成片状珠光体。 10SiCP/Fe中的界面反应更加激烈 ,SiCP 被完全消耗 ,并被由Fe3 Si和石墨颗粒构成的反应区所替代 ,金属基体因含Si量高而脆化。SiCP 表面氧化膜通过隔离原本相互接触的SiC与Fe以阻碍Fe ,Si和C原子的相互扩散 ,有利于抑制O SiCP/Fe界面反应 。

The dense oxide film of about 0.6μm is formed on the surface of the SiC particles by passive oxidation, when the SiC particles were treated at 1200°C for 10h in a stationary air ambient. The film was determined to be β-cristobalite using XRD. After treated at 1150°C for 1h in a hydrogen ambient, the interracial reaction of 3SiCr/Fe produces Fe3 Si and graphite grains to form the reaction zone in situ, and Fe3C at the crystal boundary of the metal matrix to construct the flake pearlite. The interracial reaction of 10SiCP/Fe is more severe due to increasing the reinforcement. It results in that the SiC particles are consumed completely, and the reaction zone of Fe3Si containing the random graphite precipitates forms in situ. The metal matrix of the composite is brittle due to its high Si content. The oxidation film on the oxidized SiC particles can inhibit the reaction between SiC and Fe in 3O-SiCP/Fe or 100-SiCP/Fe in temps of isolating SiC and Fe and inhibiting the interdiffusion of the Si, C and Fe atoms, which improves the interface chemical compatibility of O-SiCP/Fe.