化学镀Ni-Fe-P合金镀液组分及pH值对镀层性能的影响

Influences of Bath Composition and pH Value on Microstructure and Corrosion Resistance of Electroless Ni-Fe-P Alloy Coating

目前,对化学镀Ni-Fe-P合金镀液影响镀层形成及其阴极极化曲线的研究较少。在纯铜片表面化学镀Ni-Fe-P合金;采用扫描电镜观察了镀层的形貌,采用能谱仪测试了镀层成分,采用X射线衍射仪分析镀层的结构,采用电化学工作站测试镀层在镀液中的阴极极化曲线;通过单因素法考察了镀液组分含量及pH值对化学镀Ni-Fe-P合金沉积速率、镀层成分、形貌、结构及阴极极化曲线的影响。结果表明:镀液各组分含量及pH值对镀层性能有较大影响;最佳工艺条件为20 g/L硫酸镍,12 g/L硫酸亚铁,30 g/L次磷酸钠,40 g/L柠檬酸三钠,20 g/L硫酸铵,20 mL/L乳酸,pH值9.0,镀液温度80℃,时间1 h;此条件下所得Ni-Fe-P合金镀层以非晶态形式存在,其耐蚀性能明显优于相同工艺条件制备的Ni-P镀层。

Electroless Ni-Fe-P alloy coating was prepared on the surface of Cu plate.The morphology,composition and phase structure of as-plated alloy coating were observed with a scanning electron microscope,an energy dispersive spectrometer,and an X-ray diffractometer respectively.Moreover,an electrochemical workstation was performed to measure the cathode polarization curve of as-plated Ni-Fe-P alloy coating in the electroless plating bath;and the effects of bath composition on the deposition rate,composition,morphology,phase structure and cathode polarization curve of Ni-Fe-P alloy coating were investigated.Results indicated that the content of various ingredients of the plating bath and its pH value had significant influences on the performances of the alloy coating.The optimal bath composition was determined as 20 g/L NiSO_4 · 6H_2 0,12 g/L FeSO_4 ·7H_2O,30 g/L NaH_2PO_2 · H_2O,40 g/L C_6H_5Na_3O_7 · H_2O,20g/L(NH_4),SO_4 · H_2O and 20 mL/L lactic acid;and the optimal electroless plating condition was suggested as pH =9.0,bath temperature of 80 ℃,and plating time of 1 h.Resultant Ni-FeP alloy coating had amorpous structure,and its corrosion resistance was much better than that of Ni- P coating obtained under the same plating conditions.