保护气氛中残留氧对微弧火花沉积的影响  

Influence of Residual Oxygen on Micro-arc Spark Deposition in Shielding Atmosphere

作　　者：王维夫[1,2] 张步康 丁晨 WANG Wei-fu;ZHANG Bu-kang;DING Chen(School of Mechanical Engineering,Hangzhou310032,China;Engineering Research Center of Process Equipment and Re-manufacturing of Ministry of Education,Zhejiang University of Technology,Hangzhou310032,China)

机构地区：[1]浙江工业大学机械工程学院,杭州310032 [2]浙江工业大学过程装备及其再制造教育部工程研究中心,杭州310032

出　　处：《表面技术》2018年第12期284-289,共6页Surface Technology

基　　金：浙江省自然科学基金资助项目(LY14E050008)~~

摘　　要：目的探究微弧火花沉积过程中残留氧对沉积行为的影响。方法在不同残留氧浓度的富Ar保护气氛下进行了单脉冲、多脉冲和2 min持续沉积实验,并使用扫描电子显微镜(SEM)、光学显微镜(OM)和显微硬度计等对所获沉积层特征进行分析。结果保护气氛中残留氧为0.04%～0.06%时,沉积斑呈典型的放射状飞溅形貌,持续2 min沉积可获得局部最大厚度约140μm的平坦状沉积层。而残留氧为0.4%～0.6%和1.4%～1.6%时(其他参数不变),沉积斑表面平整,边缘无显著飞溅特征,2 min沉积试验后在基体上形成了大量新奇的微柱体/柱胚结构。质量转移规律研究表明,适当残留氧的存在能够提高质量转移效率。试验中当残留氧为0.4%～0.6%时,质量转移系数最高,可达约91%。显微硬度测试结果显示,涂层硬度约在290～330HV之间,略低于冷轧态基体的硬度(～356HV)。结论富Ar气氛中残留的微量高活性元素氧对熔池表面张力温度梯度系数有较大影响,适当残留氧的存在可使沉积斑形态从泼溅状向聚集状转变,最终导致了沉积表面微柱体/柱胚结构的出现。The works aims to study the influence of residual oxygen on micro-arc spark deposition.Single pulse,multiple pulses and 2 min deposition were performed in argon-rich shielding atmosphere with different residual oxygen concentrations.The scanning electron microscope(SEM),optical microscope(OM)and hardness tester were used to analyze the characteristics of deposition coating.When the residual oxygen concentration was 0.04%~0.06%,the deposition spots displayed a typical splashy appearance.For 2 min deposition,the irregular morphology deposited coating with a maximum thickness of^140μm was obtained.When residual oxygen concentrations were 0.4%~0.6%and 1.4%~1.6%(other parameters were the same),the deposition spots showed flat surfaces without splash on the edge.After 2 min deposition,the novelty column structures with embryos were observed on the substrate.The results of mass transfer trend showed that the mass transfer efficiency was increased with appropriate residual oxygen concentration.The maximum mass transfer coefficient was the highest about 91%,when the oxygen concentration was 0.4%~0.6%.From the hardness test results,the microhardness of coating was 290~330HV,slightly lower than the value of the substrate(~356 HV).Temperature gradient coefficient of the surface tension is dramatically affected by the residual high-active element oxygen in argon-rich shielding atmosphere.The morphology of deposition spot is changed from splash to aggregation with the existence of appropriate residual oxygen,thus resulting in the novelty column structure with embryos.

关 键 词：微弧火花沉积 氧浓度 沉积斑形貌 质量转移 显微硬度 

分 类 号：TG174.4[金属学及工艺—金属表面处理]