Study On The Process And Performance Of Chemical Ni-Sn-P Composite Platin

Iron alloys as the most widely used metal in daily life,it is great significance to improve the hardness and corrosion resistance of iron alloys to broaden their application fields and meet the needs of industrial production.In recent years,the electroless plating Ni-P technology has been studied extensively and deeply,it has been widely used because of its excellent performance.In this paper,based on the electroless plating of Ni-P on the surface of iron alloy,Sn Cl₄and nanoparticles are added to it to prepare a more excellent corrosion resistance coating.The formulation and process conditions of the electroless plated Ni-Sn-P coating were first screened by single-factor experiments,and then the formulation was further optimized by orthogonal experiments,considering the interaction effects of the plating solution components.The base plating solution formulation was obtained as follows:Ni SO₄of 30 g/L,Sn Cl₄of 16 g/L,Na H₂PO₂of 35 g/L,C₆H₅Na₃O₇of 13.5g/L,C₄H₄O₆KNa of 9.5 g/L,C₃H₆O₃of 35 g/L,SDS of 0.8 mg/L,CH₄N₂S of 0.5mg/L,plating solution p H=5.0,plating time was 60 min,and plating temperature was85°C.The final chemically plated Ni-Sn-P coating had a smooth surface,bright luster,plating rate of 9.64 mg·cm^-2·h^-1,hardness of 279 HV,and porosity of 0.28 N·cm^-2,which significantly improved the corrosion resistance compared with that of iron alloy.Then,I tried to add nanoparticles to the electroless Ni-Sn-P plating solution.Firstly,through single-factor experiments,using porosity as the main evaluation index,four kinds of nanoparticles were screened,and Fe₃O₄was determined as the plating nanoparticles.The formula of Ni-Sn-P/Fe₃O₄composite plating with the lowest porosity and highest plating rate was obtained as follows:30 g/L Ni SO₄,16 g/L Sncl₄,35 g/L Na H₂PO₂,17.5 g/L C₆H₅Na₃O₇,9.5 g/L C₄H₄O₆KNa,35 g/L C₃H₆O₃,4 mg/L SDS,0.5 mg/L CH₄N₂S,1.1 g/L nanoparticle Fe₃O₄,p H=5.0,and plated at 85°C for60 min.A composite coating with a plating rate of 8.72 mg·cm^-2·h^-1,hardness of299.8 HV,and porosity of 0.08 N·cm^-2was successfully produced.After characterization,the corrosion resistance of the composite coating was found to be greatly improved compared to the chemically plated Ni-Sn-P coating.Finally,the composite plating was subjected to heat treatment to study the effect of heat treatment at different temperatures on the plating properties.The results show that after heat treatment,the microstructure of the composite plated coating is transformed from amorphous to crystalline state,and the hardness and corrosion resistance of the plated coating are significantly improved compared with those of the untreated composite plated coating,and the composite plated coating heat treated at400°C has the best corrosion resistance and hardness.