Zn-Al—Mg-RE高速电弧喷涂工艺过程的氧化行为分析

为分析高速电弧喷涂工艺制备Zn-Al-Mg-RE防腐涂层的氧化行为，通过XRD、SEM和EDS试验探究了喷涂工艺对该涂层氧化物的组成、含量及其形态的影响规律，并测试了涂层的中性盐雾腐蚀性能。结果发现：该涂层具有典型的层状结构特征，在相互叠加的扁平颗粒之间有很薄的氧化物膜，同时在扁平颗粒的内部也非均匀地分布着富氧化物区，XRD显示这些氧化物主要为ZnO2和尖晶石结构的ZnAl2O4与MgAl2O4等。分析认为：喷涂时液态金属熔滴在高速气流剪切力作用和反应热梯度作用下，加剧了Zn-Al-Mg-RE熔滴的氧化，这些交错分布的氧化物对合金相产生了较好的屏蔽效果，从而提高了涂层的耐蚀性能。

Analysis of Oxidation Behavior of Zn-Al-Mg-RE Coating During the High Velocity Arc Spraying Process

In order to study the oxidation behavior of the Zn-Al-Mg-RE anti-corrosion coating during high velocity arc spraying, the composition, content and profiles of the coating oxides are investigated by method of XRD, SEM and EDS, the neuter salt fog corrosion property of the coating is also tested. The results show that the coating has a typical character of samdwich. Some thin oxide films are distributed between the alloy splats, and some of them are inhomogenously distributed within the alloy splats. The oxides are mainly composed of ZnO2, spinel ZnAl2O4 and MgAl2O4 from XRD results. It is concluded that, the main cause of high content oxide for the Zn-Al-Mg-RE coating lies in the high velocity gas flow induced shearing force and the reaction induced heat grads acting on the liquid metal droplets. A shield effect for the alloy is obtained from the inter-distributed oxide films, and the corrosion resistance of the coating is therefore improved.