不锈钢激光熔敷纯Ni粉末涂层的组织和腐蚀行为  

Microstructure and corrosion behavior of pure Ni powder coating on stainless steel surface by laser cladding

作　　者：杨健[1] 谢燕翔 YANG Jian;XIE Yanxiang(Yulin Engineering Technology Research Center for Frontier Materials,College of Energy Engineering,Yulin University,Yulin 719000,China;Shaanxi Key laboratory of Surface Engineering and Remanufacturing,Xi＇an University of Arts and Science,Xi＇an 7100130,China)

机构地区：[1]榆林学院能源工程学院榆林市新材料技术研究中心,陕西榆林719000 [2]西安文理学院陕西省表面工程与再制造重点实验室,陕西西安710000

出　　处：《兵器材料科学与工程》2018年第6期34-39,共6页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(51601167;51861034);陕西省科技统筹重大项目(2016KTZDGY04-03;2018GY-129);陕西省教育厅专项科研计划项目(18JK0907)

摘　　要：以纯Ni粉末作为熔敷材料,用光纤激光器在316L不锈钢表面进行激光熔敷。用SEM、EDS、XRD分析熔敷涂层的组织形貌与物相组成,采用电化学方法研究涂层与基材在3.5%NaCl溶液中的腐蚀行为。结果表明:涂层表面光滑,微观结构致密,与基材结合良好,涂层主要为γ(Ni,Fe)固溶体和FeNi3相,从顶部到底部组织形态依次为等轴晶、柱状晶、胞状晶,界面结合区为平面晶;涂层的自腐蚀电位为-0.13 V,电流密度为5.012×10-7A/cm2,相比于不锈钢基材,涂层的自腐蚀电位提高0.16 V,电流密度降低55.33%,腐蚀阻抗值高于基材,涂层表面钝化膜无夹杂物,完整性更高,点蚀萌生更加困难,同时可降低点蚀扩展速率,保护不锈钢基材。The pure Ni powder was deposited on the surface of 316L stainless steel with fiber laser. The microstructure and phase composition of the coating were analyzed by SEM, EDS and XRD. The corrosion behavior of coating and substrate in 3.5%NaCI solution was investigated by using electrochemical method. The results show that the surface of the coating is very smooth and the coating has a dense structure bonded well with the substrate. The coating consists ofγ （Ni, Fe） solid solution and FeNi3 phase. From the top to bottom, the morphology of microstructure is equiaxed crystal, columnar crystal and cellular crystal in turn. The interface zone is planar crystal, the self-corrosion potential of coating is -0.13 V and corrosion current density is 5.012× 10^-7 A/ cm^2. Compared with the substrate, the self-corrosion potential shifts positively by 0.16 V and the corrosion density of coating decreases by 55.33%. The corrosion impedance modulus of coating is also significantly higher than that of substrate. The passivation film on the surface of coating has higher integrity without inclusion defects, which makes the initiation of pitting become more difficult and can reduce the rate of pitting, and Ni coating acts to protect the stainless steel substrate.

关 键 词：316L不锈钢 纯Ni粉末 激光熔敷 微观组织 腐蚀行为 

分 类 号：TG178[金属学及工艺—金属表面处理]