三乙醇胺络合剂对化学镀Ni-W-P合金镀层结构与性能的影响

目的研究以三乙醇胺作为络合剂对化学镀Ni-W-P合金镀层的组织结构和腐蚀性能的影响。方法以化学镀的方法在40Cr基体上制备Ni-W-P合金镀层,研究了三乙醇胺对Ni-W-P合金镀层的成分结构、沉积速率、耐蚀性和孔隙率的影响。结果三乙醇胺用量为8 m L/L时镀层W、P质量分数达到峰值,分别为3.63%、9.34%。三乙醇胺用量较低时,镀层具有非晶态结构;三乙醇胺用量达到12 m L/L时镀层开始出现晶态峰,具有混晶态结构。三乙醇胺浓度对镀层的沉积速率和孔隙率具有很大影响,三乙醇胺用量为10 m L/L时,镀速达到最大值14.1μm/h,用量为8 m L/L时,镀层的孔隙率最低,为0.07%。化学镀Ni-W-P合金镀层的耐蚀性随着三乙醇胺浓度的增加,具有先增加后降低的趋势,用量为8 m L/L时,镀层的腐蚀速率最低,为5.6μm/a,耐蚀性最好。结论以三乙醇胺作为络合剂能够得到胞状颗粒且颗粒均匀细小的Ni-W-P合金镀层,对镀层的结构具有一定的影响,可以提高Ni-W-P合金镀层的沉积速率。Ni-W-P合金镀层具有很好的耐蚀性,腐蚀速率最低为5.6μm/a。

Research in the Effect of Trolamine Complexing Agent on Structure and Properties of Electroless Ni-W-P Alloy Coating

ABSTRACT:Objective To research the effect of trolamine complexing agent on structure and properties of electroless Ni-W-P alloy coating.Methods Ni-W-P alloy coating was prepared on 40Cr substrate by chemical plating. The effect of trola-mine on structural components, deposition rates, corrosion resistance and porosity of Ni-W-P alloy coating was investigated. Results When concentration of trolamine was 8 mL/L, the mass fraction of coating W and P reached at the peak 3.63% and 9.34% respectively. The coating was amorphous structure when concentration of trolamine concentration was low while it began to take on cystalline state peak and have mixed cystalline when the concentration reached 12 mL/L. Trolamine concentration had great influence on the deposition rate and porosity of the coating. The deposition rate reached maximum 14.1μm/h as the trola-mine concentration increased, and the coating porosity reached minimum 0.07% when the trolamine concentration decreased to 8 mL/L. The corrosion resistance of the Ni-W-P alloy coating tended to firstly increase and then fall down with the increasing trolamine concentration in plating bath. The Ni-W-P alloy coating had the best corrosion resistance at corrosion rate of 5.6μm/a and concentration of 8 mL/L.ConclusionThe use of trolamine as complexing agent can produce Ni-W-P alloy with uniform and fine cellular particles and has a certain influence on the structure of the coating. It can improve the deposition rate of the Ni-W-P alloy coating. The Ni-W-P alloy coating has good corrosion resistance with the minimum corrosion rate at 5.6μm/a.