快速化学镀 Ni-Zn-P 合金工艺及镀层性能

目的确定快速化学镀Ni-Zn-P合金的工艺。方法通过一系列实验,研究主盐含量、pH值、温度、时间等对镀层沉积速度及镀层锌镍比的影响,确定最优工艺条件。借助SEM,EDS,XRD及电化学方法分析镀层微观形貌、成分及耐蚀性。结果在ZnSO4·7H2O8 g/L,NiSO4·6H2O 35 g/L,NaH2PO2·H2O20 g/L,NH4Cl 50 g/L,C6H5Na3O7·2H2O 70 g/L,稳定剂1.5 mg/L,p H=9.0,温度90~95℃的条件下,化学镀Ni-Zn-P合金沉积速度为5~6μm/h,镀层中Zn质量分数为8%~10%,P质量分数为6%左右,Ni质量分数为80%~85%。Zn的存在使Ni呈现出晶态结构,在XRD谱图上2θ=45°及2θ=52°位置分别出现了Ni(111),Ni(200)衍射峰。施镀时间不会影响镀层成分,但会影响镀层耐蚀性。施镀1.5 h时,镀层厚度约为9~10μm,其耐蚀性略好于相同厚度的Ni-P镀层。结论 Ni-Zn-P化学镀沉积速度较快,8%~10%的Zn使镀层中Ni呈晶态结构,且改善了镀层耐蚀性。

Rapid Electroless Technique for Ni-Zn-P Alloy Coating and Its Properties

ABSTRACT:Objective To determine a rapid electroless technique for Ni-Zn-P alloy coating. Methods The effects of the concen-tration of main salts, pH, temperature and electroless time on the deposition rate and Zn : Ni ( wt.%) of coating were studied by a series of experiments. An optimized electroless technique for Ni-Zn-P alloy was achieved. The morphology, composition, phase structure and corrosion resistance of the coating were analyzed by SEM, EDS, XRD and EIS, respectively. Results Ni-Zn-P alloy coating was prepared on carbon steel by the electroless technique when ZnSO4 ·7H2 O, NiSO4 ·6H2 O, NaH2 PO2 ·H2 O, NH4 Cl, C6 H5 Na3 O7 ·2H2 O, stabilizing agent, pH and temperature were 8 g/L, 35 g/L, 20 g/L, 50 g/L, 70 g/L, 1. 5 mg/L, 9. 0 and 90~95 ℃, respectively. The deposition rate of the coating was 5~6 μm/h. The contents of Zn, Ni and P in the coating were 8wt.% ~10wt.%, 80wt.% ~85wt.% and about 6wt.%, respectively. Besides, the Ni in the coating showed crystalline struc-ture in the presence of Zn. The diffraction peaks of Ni (111) and Ni (200) appeared at 2θ=45 ° and 2θ=52 °. In addition, elec-troless time had slight influence on the coating composition, but could affect the corrosion resistance of the coating. The thickness of Ni-Zn-P alloy coating was about 9~10 μm when the electroless time was 1. 5 h. The Ni-Zn-P coating with a thickness of 9~10μm had better corrosion resistance than the Ni-P coating with the same thickness. Conclusion The electroless deposition rate for Ni-Zn-P coating was higher. The presence of 8wt.% ~10wt.% Zn led to the formation of crystalline Ni in the coating, and im-proved the corrosion resistance of the coating.