氮化与未氮化38CrMoAlA钢高温水蒸汽氧化比较

Comparison of high temperature oxide-resisting between nitrided and non-nitrided 38CrMoAlA steel

通过高温氧化实验,比较了氮化与未氮化38CrMoAlA钢的抗高温氧化性能;利用扫描电镜及能谱仪分析了氮化与未氮化38CrMoAlA钢氧化膜中各元素的分布,以及所形成的氧化物形貌特征.结果表明,氮化后的38CrMoAlA钢较未氮化的38CrMoAlA钢氧化速度快,主要原因是氧与氮化物在高温高压水蒸气条件下发生反应,O置换了N,而且未能在氧化膜中富集Si、Al元素形成保护性氧化膜,使得氮化试样的表面及基体内部沿晶界处产生了氧化物.

The properties of high temperature oxide-resisting of nitrided and non-nitrided 38CrMoAlA steels were compared by the high temperature oxide experiments. The morphologies of the oxides and the distribution of several important elements in the oxide film in the two kinds of 38CrMoAlA steels were analyzed by scanning electron microscope and XRD, which indicated that the rate of oxidation in the nitrided 38CrMoAlA specimen was higher than that in the non-nitrided specimen. The main reason is that oxygen reacts with nitride and replaces the nitrogen of the nitride under the high temperature and pressure vapor environment, and silicon and aluminum can not enrich in the oxide film and form the protective oxide film. As a result, the oxide forms not only on the surface but also along the crystal boundary of the matrix of the non-nitrided 38CrMoAlA steel specimen.