钴棒表面Co-Ni合金电镀及耐蚀性能研究  

Electroplating and Corrosion Resistance of Co-Ni Alloy Coating on Cobalt Rod

作　　者：鲁道荣[1] 付文杰[2] 詹子明[2] 刘杨成 冉念波 高婧颖 

机构地区：[1]合肥工业大学化学与化工学院,合肥230009 [2]合肥工业大学化工与食品加工系,安徽宣城242000

出　　处：《表面技术》2016年第12期154-160,共7页Surface Technology

基　　金：安徽省教学研究项目(2014jyxm037);合肥工业大学创新实验项目(2015CXCY531)~~

摘　　要：目的提高制备钴60放射源的钴棒在高温空气中的抗氧化能力。方法在金属钴棒表面先电镀Co-Ni合金,再电镀镍,最后在600℃的氢氩混合气中煅烧30 d。用电化学方法研究镀层的耐蚀性能,用XRD、EDS和SEM研究镀层的结构与组成及腐蚀前后的形貌变化。结果通过正交实验获得钴镍合金最佳电镀工艺条件为:电流密度55 m A/cm2,镀液温度65℃,p H=4.0,电镀时间25 min。以30℃、3.5%Na Cl溶液为腐蚀介质,进行塔菲尔曲线、阳极极化曲线、交流阻抗等测试,研究表明存在Co-Ni合金镀层,明显提高了Co棒的耐腐蚀性能。XRD测试表明,煅烧后,钴棒表面的镍镀层不改变面心立方结构。EDS测试表明,钴镍合金镀层中的镍质量分数为89.71%。SEM测试表明,纯钴腐蚀前后形貌变化厉害,钴镍合金腐蚀前后形貌变化不明显。结论介于钴与镍之间的钴镍合金镀层能增强镍在钴棒上的附着力和高温下的耐蚀性能。The work aims to improve corrosion resistance of cobaltrod, which is used to prepare Co-60 radioactive source, in high temperature air. Firstly, cobalt-nickel alloy was electroplated on the cobalt rod, and then nickel was electroplated. Finally, it was calcined in 600 ℃ mixed hydrogen and argon gas for 30 days. Corrosion resistance of the coating was analyzed by means of electrochemical method. The structure, composition and morphology changes before and after corrosion were studied by XRD, EDS and SEM. Optimal electroplating process conditions of Co-Ni alloy obtained from orthogonal experiment were： current density of 55 m A/cm^2, solution temperature of 65 ℃, p H value of 4.0 and electroplating time of 25 min. Tafel curves, anodic polarization curves and AC impedance were tested with 3.5% Na Cl solution at 30 ℃ as corrosive medium. Studies showed that Co-Ni alloy coating was present, which has increased the corrosion resistance of Co rod significantly. XRD test showed that the calcination of nickel coating did not change face-centered cubic structure. EDS test showed that nickel mass fraction accounted for 89.71% of the Co-Ni alloy coating. SEM indicated that morphology of pure cobalt changed dramatically after corrosion while that of Co-Ni alloy changed slightly after corrosion. The Co-Ni alloy coating between cobalt and nickel can enhance the adhesion of nickel to cobalt rod and its corrosion resistance at high temperature.

关 键 词：正交实验 Co-Ni合金 电镀 耐腐蚀性能 

分 类 号：TG174.42[金属学及工艺—金属表面处理]