不同金属盐对水合肼化学镀镍层耐蚀性能的影响

Corrosion Resistance of the Coating Affected by Different Metal Salts in Hydrazine Hydrate Electroless Nickel Plating

目的对比研究三种金属盐的化学镀镍层组织和性能,选出最佳金属盐,并开发出一种以水合肼为还原剂的化学镀镍新配方。方法采用金相显微镜、扫描电镜(SEM)等形貌表征手段,测厚法、质量法等速度表征手段,及盐雾实验和电化学极化曲线测试等耐蚀性表征手段,分别研究硫酸镍(NiSO_4·6H_2O)、碳酸镍(NiCO_3·2Ni(OH)_2·4H_2O)和氨基磺酸镍(Ni(NH_2SO_3)_2·4H_2O)三种金属盐对Fe基体化学镀镍层形貌、沉积速度和耐蚀性能的影响。结果以水合肼为化学镀镍液中的还原剂,在其他实验条件相同时,镀层形貌依次为硫酸镍最优,氨基磺酸镍次之,碳酸镍较差。采用厚度法计算得到化学镀镍沉积速度,碳酸镍平均镀速为5.33μm/h,氨基磺酸镍为4.83μm/h,硫酸镍为4.00μm/h。耐蚀性能与形貌对应,硫酸镍镀层盐雾实验出现锈点时间最晚,电化学极化曲线测试表明其自腐蚀电位最正,腐蚀电流最小,耐蚀性能最好,而氨基磺酸镍次之,碳酸镍最差。结论将耐蚀性能作为选择金属盐标准,选择硫酸镍金属盐时,化学镀镍沉积速度最慢,此时形成的镀镍层形貌最好,耐蚀性能最佳,因此硫酸镍为水合肼化学镀镍金属盐的最佳选择。

The work aims to develop a new formula of electroless nickel plating with hydrazine hydrate as reducing agent by comparing the microstructure and properties of electroless nickel plating of three metal salts and selecting the best metal salt.The effect of three metal salts(NiSO4·6H2O,NiCO3·2Ni(OH)2·4H2O,Ni(NH2SO3)2·4H2O)on morphology,plating rate and corrosion resistance of hydrazine hydrate electroless nickel plating on metal Fe was studied by morphology characterization means of metalloscope and scan electron microscope(SEM),rate characterization means of thickness measurement and weight method and corrosion resistance characterization means such as salt spray experiments and electrochemical polarization curve tests.With hydrazine hydrate as reducing agent in the electroless nickel plating solution,when other factors were the same,nickel sulfate had the best coating microstructure,followed by nickel aminosulfonate and nickel carbonate had the worst.The rate of electroless nickel plating was calculated by thickness method,the average rate of nickel carbonate plating was 5.33μm/h,the average rate of nickel aminosulfonate plating was 4.83μm/h,and the average rate of nickel sulfate plating was 4.00μm/h.Corrosion resistance corresponded to morphology,the rust spot time of nickel sulfate coating in salt spray experiment was the latest,corrosion potential was the most positive and corrosion current was the least.The coating corrosion resistance of nickel sulfate was the best,followed by nickel aminosulfonate and nickel carbonate had the worst.Taking corrosion resistance as the standard for selecting metal salt,when nickel sulfate was selected as the metal salt,the deposition rate of electroless nickel plating is the slowest and the formed nickel plating layer has the best morphology and the best corrosion resistance,so nickel sulfate is the best choice of hydrazine hydrate electroless nickel plating metal salt.