Fe_3Al高温氧化中的内氧化

The Internal Oxidation of Fe_3Al in High Temperature Oxidation

用热天平、扫描电子显微镜（SEM）、能谱（EDX）和X-射线衍射（XRD）研究了Fe3Al在1000℃空气中的氧化行为。发现氧化动力学基本服从抛物线规律，氧化膜由Al2O3和少量Fe2O3组成，并产生穿晶内氧化；根据对氧化膜及基体的分析结果及有序合金扩散热力学特点，提出发生内氧化的主要原因是金属间化合物的有序结构降低了铝的活度和其在合金中的扩散系数，在高温氧化过程中，基体／氧化膜界面严重贫铝，从而发生内氧化。

The oxidation behaviour of Fe3Al at 1000 ℃ in air has been studied by means of electric thermal balance, scanning electron microscopy(SEM) and X-ray diffraction. The experiments demonstrate that the kinetics of oxidation approximately follows the parabolic law. The oxide scale consists mainly of Al2O3. However, the transgranular internal oxidation is found at the convex area of matrix. It is suggested that the main reason for the internal oxidation is that the activity and diffusion coefficient of Al in the matrix are decreased by the ordered structure of intenrmetallic compound Fe3Al and that the convex surface of the matrix contacted with the oxide scale is poor in Al.