铝合金表面电镀镍的耐腐蚀性能

在铝合金表面电镀镍,考察镀液温度、电流密度和镀液pH值等因素对镀层耐蚀性能的影响,获得最佳电镀条件下的镍镀层.选择3.50%NaCl溶液作为腐蚀介质,采用稳态阳极极化曲线法研究镀层的耐蚀性能.用SEM和XRD研究镍镀层在腐蚀前后的微观结构和表观形貌的变化.结果表明镀镍的最佳工艺条件为温度50℃、电流密度30mA/cm2、镀液pH值3.82.XRD测试表明镍镀层的结构为立方晶系,晶面择优取向为(111),腐蚀前后晶面择优取向不变,但(111)晶面的织构系数由35.35%增至61.73%,说明低指数晶面(111)具有较好的耐蚀性能.SEM测试表明最佳条件下制备的半光亮镍镀层均匀致密,具有较好的耐腐蚀性能.

Corrosion Resistance of Nickel Electroplating on Aluminum Alloy

Nickel coating was electroplated on the surface of aluminum alloy.The effect of the temperature of solution and current density and solution pH on the corrosion resistance of the coating were studied.The Nickel coating were obtained under the optimum conditions.The corrosive medium was 3.50% sodium chloride solution.The corrosion resistance of nickel coating was researched by steady-state anodic polarization curves.The morphology of apparent and microstructure change before and after corrosion of the nickel coating were researched by SEM and XRD.The results indicated that the temperature at 50 ℃,the current density 30 mA/cm2,the solution pH value 3.82 is the best process conditions.XRD tests showed that the structure of nickel coating is cubic crystal system,and crystal preferred orientation(111) unchanged before and after corrosion,but texture coefficient of(111) was increased from 35.35% to 61.73%.and that the orientation(111) had better corrosion resistance was showed.SEM test showed that the semi-bright nickel plating with uniform and compact was prepared under the optimum conditions.It had good corrosion resistance.