微弧火花单脉冲沉积斑形貌分析

The morphology analysis of single pulse deposition spot on micro-arc spark deposition

为了探索微弧火花单脉冲沉积机制,采用铁基合金进行单脉冲沉积实验。使用扫描电镜(SEM)对沉积斑的表面形貌进行观察并分析其形成过程。结果表明微弧火花作用下的单脉冲沉积斑形貌可以分为3类:飞溅沉积斑、熔滴粘连沉积斑和凌乱破碎沉积斑。分析认为3类沉积斑的形成本质是一致的,都是通过气体介质电离击穿、放电通道的建立和熔滴过渡所产生的,而熔滴过渡过程中的受力及受力方式的不同导致其沉积斑的多样性;此外,高温下熔体的表面张力对沉积斑形貌也有影响。

In order to study the mechanism of single pulse deposition.The single pulse deposition tests of Fe based alloy was carried out.The scanning electron microscope(SEM)was employed to analysis the morphology of the single spot and the formation process.The result shows that the morphology of single spots could be divided into three types in micro arc spark deposition,the splash spot,droplet adhesion spot and messy broken spot.The analysis results shows that the formation mechanism of three kinds of spots is consistent.They are produced by the breakdown of the gas medium,the establishment of the discharge channel and the droplet transfer.The different stress and stress modes in the droplet transfer process and the surface tension of the molten droplets at high temperature result in different morphology of deposition spots.In addition,the surface tension of the melt at high temperature also affects the morphology of the deposition spot.