硫酸镍浓度对脉冲电沉积Ni-W-P合金的影响

Influence of Nickel Sulfate Concentration on Microstructure and Corrosion Resistance of Pulse Electrodeposited Ni-W-P Alloy Coating

Ni—W—P三元合金镀层用于油井设备防腐蚀效果优良，但目前采用脉冲电沉积法制备该三元合金的工艺尚不成熟。利用脉冲电沉积法在抽油杆钢30CrMo表面制备Ni-W—P三元合金镀层，通过电子探针（EPMA）及X射线衍射（XRD）分析，研究了镀液中不同硫酸镍浓度对镀层化学成分及结构的影响，采用显微硬度计和Tafel极化曲线测试考察了镀层的硬度及耐蚀性。结果表明：硫酸镍浓度为70～80g／L时，镀层中W，P含量较高且为非晶结构，镀层具有较高的硬度和较好的耐蚀性；脉冲电沉积Ni—W-P镀层的过程符合诱导共沉积机理。

Ni-W-P ternary alloy coating was prepared on 30 CrMo sucker rod steel substrate by pulse electrodeposition.The elemental composition and crystalline structure of as-deposited Ni-W-P alloy coating were analyzed by electron probe microanalysis and X-ray diffraction.A microhardness meter was performed to determine the microhardness of the alloy coatings,and an electrochemical test rig was performed to measure their Tafel polarization curves.Furthermore,the effect of nickel sulfate concentration in the plating bath on the microstructure and corrosion resistance of the as-deposited Ni-W-P alloy coatings was investigated.It was found that,when the concentration of nickel sulfate was in the range of 70~80 g/L,as-deposited Ni-W-P coating had amorphous structure as well as high contents of W and P and good corrosion resistance.In the meantime,the pulse electrodeposition process of Ni-W-P coating was dominated by induced codeposition.