镁合金表面热喷涂WC-10Co-4Cr粒子沉积及分布特性

Deposition and Distribution Characteristics of WC-10Co-4Cr Particles on Magnesium Alloy Surface by Thermal Spraying

为了探究高速空气燃料热喷涂(activated combustion-high velocity air fuel,AC-HVAF)过程中喷涂粒子撞击基材后的沉积特性。采用AC-HVAF热喷涂技术在AZ80镁合金基体上沉积WC-10Co-4Cr硬质涂层。通过离散沉积实验获得薄层沉积粒子,探讨各种沉积形貌的种类、形成原因、结合机制及射流中粒子的径向和轴向分布。结果表明:在AC-HVAF粒子沉积过程中,嵌入型沉积为主要的沉积形貌,同时包含少量的破碎型与空腔型沉积粒子。在涂层的形成过程中,嵌入型沉积对涂层/基体结合性能起重要作用;空腔型沉积的小颗粒及破碎型沉积的大颗粒是造成沉积效率下降的主要原因。喷涂粒子主要集中在射流中心,越靠近射流边缘,空腔型沉积粒子越多,最终导致AC-HVAF粒子射流呈现出空间分布特征。

In order to investigate the deposition characteristics of spray particles after impacting the substrate during activated combustion-high velocity air fuel(AC-HVAF)thermal spraying process.WC-10Co-4Cr coatings were deposited on AZ80 magnesium alloy substrate by AC-HVAF thermal spraying technology.Thin layer of deposited particles were obtained by discrete deposition experiments.Types of various morphologies after deposition,formation reasons,binding mechanisms and radial and axial distributions of particles in the jet were discussed.The results show that in the process of AC-HVAF particle deposition,the embedded deposition is the main deposition morphology,and contains a small amount of broken and hollow deposition particles.In the formation process of the coating,the embedded deposition plays an important role in the bonding performance of the coating-substrate.The small cavity type deposition particle and the large broken type deposition particle are the main reasons for the decline of deposition efficiency.The spray particles are mainly concentrated in the jet center,and the closer to the jet edge,the more cavity type particles are deposited,which ultimately leads to the spatial distribution characteristics of AC-HVAF particle jet.