等离子喷涂涂层重熔后处理的研究现状与展望

Current Research Status and Prospect of Plasma Spraying Coating Remelting Post Treatment

鉴于喷涂涂层存在的较高孔隙率和较大残余应力而常常需要进行适当的后处理,介绍了等离子喷涂涂层的几种重熔后处理技术,对各种处理方式进行归纳总结,并分析了各种处理方式的优缺点。对未来喷涂涂层重熔后处理技术进行展望,提出了根据涂层性质选择合适后处理方式、进一步优化后处理工艺、建立涂层寿命监测系统并进行涂层失效预测等提高涂层使用性能的建议。有关研究说明:喷涂涂层的激光重熔后处理技术能让涂层与基体间由机械结合为主转为以冶金结合为主,可有效增强涂层的硬度、耐磨性、耐腐蚀性及抗高温氧化性等,且其选材的来源广泛,热影响区和工件的变形量较小,但激光重熔时涂层易出现裂纹,因此不宜对大面积涂层进行激光重熔后处理;喷涂涂层的感应重熔后处理技术热影响区较小,可消除涂层中的气孔和微裂纹,有效增强涂层的耐磨性和耐腐蚀性,但感应重熔过程会受到涂层自身电阻率的限制而降低重熔后处理的效率;喷涂涂层的电子束重熔后处理技术适用范围广,成本较低,无污染,可有效提高涂层的硬度、耐磨性和抗氧化性能,减少涂层间的气孔,降低涂层表面的粗糙度,但电子束重熔过程对工作环境要求较高;喷涂涂层的火焰重熔后处理技术操作简单、成本较低,喷涂涂层的钨极氩弧重熔后处理技术易于控制,可有效保护涂层,获得高质量的重熔层,但喷涂涂层的火焰重熔后处理技术和钨极氩弧重熔后处理技术也各有缺陷,因此应根据涂层性质和用途选择合适的涂层后处理方式。

In view of the higher porosity and residual stress of spraying coating,the proper post-treatment is often needed.Several remelting post-treatment technologies of plasma spraying coating are introduced,various treatment methods are summarized,and the advantages and disadvantages of each treatment method are analyzed.The prospect of the post treatment technology for the remelting of unpainted coatings is presented,and some suggestions for improving the coating performance are put forward,such as selecting appropriate post treatment technology according to the coating properties,further optimizing the post treatment process,establishing a coating life monitoring system,and predicting the coating failure.Relevant research shows that the laser remelting post-treatment technology of spraying coating can change the main bonding method between the coating and the substrate from the mechanical way to the metallurgical way,which can effectively enhance the hardness,wear resistance,corrosion resistance and high-temperature oxidation resistance of the coating.Moreover,it has a wide range of sources of materials,and the deformation of the heat affected zone and workpiece is small.However,the coating is prone to crack during laser remelting,so it is not suitable to carry out laser remelting post-treatment on large areas of the coating;The induction remelting post-treatment technology for spraying coating has a small heat affected zone,which can eliminate pores and microcracks in the coating and effectively enhance the wear resistance and corrosion resistance of the coating.However,the induction remelting process will be limited by the resistivity of the coating itself,reducing the efficiency of post remelting treatment;The post treatment technology of electron beam remelting for spraying coating has wide application scope,low cost and no pollution,which can effectively improve the hardness,wear resistance and oxidation resistance of the coating,reduce the pores between the coatings,and reduce the roughness of the coating surface.However,the electron beam remelting process has high requirements for the working environment;The flame remelting post-treatment technology of sprayed coatings is simple in operation and low in cost.The tungsten argon arc remelting post-treatment technology of sprayed coatings is easy to control,which can effectively protect the coatings and obtain high-quality remelting coatings.However,the flame remelting post-treatment technology and tungsten argon arc remelting post-treatment technology of sprayed coatings also have their own defects.Therefore,appropriate coating post-treatment methods should be selected according to the nature and use of the coatings.