目的 提高IN 718涂层的抗氧化性。方法 向IN 718镍基粉末中添加2%Si粉，使用等离子熔覆技术在H13钢表面制备涂层。利用线切割将涂层从基体上剥离，使用高温炉在静态空气中进行900、1000、1100 ℃的循环氧化实验，测试了Si改性IN 718涂层的抗高温氧化性能，通过XRD、SEM、EDS分析了涂层及其氧化层的组织、成分的变化。结果 添加Si改变了涂层的微观组织，增加了等轴晶的含量，提升了涂层的显微硬度。两种涂层在900 ℃的氧化动力学曲线基本一致，氧化层均为Cr2O3。IN 718在1000~1100 ℃中氧化层为Cr2O3，根据热力学计算结果，Si元素活性在900 ℃以后大幅提高，因此IN 718+Si涂层在1000 ℃以及1100 ℃生成了双层氧化层，外层为Cr2O3，内层为SiO2。结论 添加Si元素提高了IN 718涂层在1000 ℃以上的抗高温氧化性能。

In order to improve the oxidation resistance of IN 718 coating, 2wt.%Si powder was added into IN 718 Ni-based powder to prepare coating on H13 steel surface by plasma cladding technique. The coating was separated from the substrate by wire cutting. The cyclical oxidation experiments at 900 ℃, 1000 ℃ and 1100 ℃ respectively were carried out in a high temperature furnace in static air. The high temperature oxidation resistance of the Si-modified IN 718 coating was tested. The changes of microstructure and composition of the coating and its oxide layer were analyzed by XRD, SEM and EDS. The addition of Si changed the microstructure of the coating, increased the content of equiaxed crystal, and improved the microhardness of the coating. The oxidation kinetic curves of the two coatings at 900 ℃ were basically the same, and the oxide layers were all Cr2O3. IN 718 oxide layer was Cr2O3 at 1000~1100 ℃. According to the Thermo-calculation result, the Si activity was greatly increased above 900 ℃, which results in that a double layer of oxide layer was genarated on the IN 718+Si coating at 1000 ℃ and 1100 ℃, the outer layer was Cr2O3, and the inner layer was SiO2. The high temperature oxidation resistance of IN 718 coating over 1000 ℃ was improved owing to Si addition.