脉冲电镀Ni-Cr-Mo合金镀层的制备及电沉积行为研究

发布时间：2018-06-19 02:29

  本文选题：脉冲电镀 + Ni-Cr-Mo合金镀层　； 参考：《华北理工大学》2017年硕士论文

【摘要】：为提高Q235钢的耐海水腐蚀性能,采用脉冲电镀法在Q235钢表面制备了Ni-Cr-Mo合金镀层。采用辉光放电光谱仪、扫描电镜、贴滤纸法、塔菲尔曲线和电化学阻抗谱研究了镀液组分、柠檬酸铵含量、尿素含量、镀液温度、p H值、平均电流密度、占空比和施镀时间对镀层元素组成、沉积速率、表面形貌、孔隙率和耐蚀性的影响,确定了最优镀液组成和最优工艺参数。最优镀液组分Ni SO4·6H2O、Cr Cl3·6H2O与Na3Mo O4·2H2O摩尔浓度比为10:1:1,最优柠檬酸铵含量为0.6 mol·L-1,最优尿素含量为1.0 mol·L-1。最优工艺参数分别为镀液温度30℃、p H值3.5、平均电流密度10 A·dm-2、占空比0.2、施镀时间50 min。采用直流、单脉冲和换向脉冲三种电沉积方式制备的合金镀层中,换向脉冲方式制备的Ni-Cr-Mo合金镀层表面粗糙度最低,耐蚀性最好。采用极化曲线、循环伏安曲线、电化学阻抗谱和计时电流曲线研究了Ni-CrMo合金的电沉积行为。柠檬酸盐-尿素体系Ni-Cr-Mo合金沉积为受扩散控制的不可逆过程,存在活性中间产物在电极表面的吸附,存在形核过程。
[Abstract]:In order to improve the corrosion resistance of Q235 steel, Ni-Cr-Mo alloy coating was prepared on Q235 steel surface by pulse electroplating. The composition of bath, ammonium citrate content, urea content, bath temperature and average current density were studied by means of glow discharge spectrometer, scanning electron microscope, filter paper method, Tafel curve and electrochemical impedance spectroscopy. The effects of duty cycle and plating time on the element composition, deposition rate, surface morphology, porosity and corrosion resistance of the coating were investigated. The optimum bath composition and process parameters were determined. The molar ratio of Ni so 4 6H 2O to Na 3MoO 4 2H 2O is 10: 1: 1, the optimum ammonium citrate content is 0.6 mol L -1 and the optimum urea content is 1.0 mol L -1. The optimum process parameters are as follows: bath temperature 30 鈩，

本文编号：2037955