Q235钢上中温化学镀镍磷合金工艺

摘要

The effects of the contents of sodium citrate and lactic acid as complexing agents in bath, and pH on the deposition rate of electroless nickel coating at medium temperature on Q235 steel substrate were studied by orthogonal test. The effects ofbenzotriazole, sodium thiosulfate and mixture thereof on the bath stability and deposition rate were discussed. The optimal formulation and operation conditions were obtained as follows: NiSO4·6H2O 30 g/L,NaH2PO2·H2O 30 g/L, lactic acid 50 g/L, sodium citrate 2 g/L, CH3COONa·3H2O 1-3 g/L, eomplexing agent (composed of sodium thiosulfate and benzotriazole at a mass ratio of 1: l)20 mg/L, ammonia water as required, temperature 70 ℃, pH 5, and loading capacity 1 dm2/L. The coatings obtained feature phosphorus content of 8.2％, uniform and compact surface, amorphous microstructure, low porosity, high adhesion strength, and good corrosion resistance.%采用正交试验考察了镀液中配位剂柠檬酸钠和乳酸钠含量及pH对Q235碳钢上中温化学镀层沉积速率的影响,研究了稳定剂苯并三氮唑、硫代硫酸钠及其复配对镀液稳定性和沉积速率的影响.得到较理想的工艺配方及操作条件为:NiS046H2O30 g/L,NaH2PO2·H2O 30 g/L,乳酸50 g/L,柠檬酸钠2 g/L,CH3COONa·OH20 1～3g/L,由硫代硫酸钠与苯并三氮唑按质量比1:1复配的稳定剂20 mg/L,缓冲剂氨水适量,温度70℃,pH =5,装载量1 dm2/L.在此条件下,镀层含磷8.2%,表面均匀、致密,为非晶态结构,孔隙率低,结合力强,耐蚀性好.