Studies On Transform The Spent Bath Of Electroplating Nickel-Phosphorus Alloy Plating To Electroless Plating Solution

The electroplate Nickel-Phosphorus coating is applying in astronautics,mechanism, transportation, home appliances and so on. But electroplating is one of the most serious three polluting industry in the world. Spent electroplating bath is dangerous discard article, because it contains many heavy metals such as zinc, nickel, chromium, cadmium, etc.A new treatment technology of spent bath of electroplating Nickel-Phosphorus alloy plating was developed in this paper.Plentiful literature were perused in preliminary study. And the elementary component of solution transformed for Ni-P alloy coating and provisional technique parameters of preparing Ni-P alloy coating by solution transformed were confirmed in this paper. Based on the prophase study, we discussed the effect of reducing agent, complexing agent, pH value,buffer, stability agent, Nickel ion concentration in solution transformed on the deposition rate and stability of the solution transformed. The results showed that the Thiourea and Sodium acetate anhydrous concentration strongly affects the deposition rate and stability of the solution transformed and the following factors are Sodium hypophosphite, Lactic acid, Lead acetate and Nickel ion concentration in solution subsequently. Based on the above conclusion, we established the superlative primary component of solution transformed for Ni-P alloy coating. It is that the concentration of Nickel sulfate in solution was 36.82g/L; Sodium hypophosphite concentration was 37.32g/L; Lactic acid concentration was 41.80mL/L; Sodium acetate anhydrous concentration was 20g/L; Thiourea was 0.002g/L. Based on the prophase experiment, we analysed the effect of temperature, pH value and loading rate on the the deposition rate of the solution transformed. The results showed that the temperature and pH value effectively affects the deposition rate of the solution transformed and the following factors are loading rate subsequently. Based on the above conclusion, we established the primary superlative technological of solution transformed for Ni-P alloy coating. It is that the temperature was 90-92℃;the pH value was 4.5-4.8.According to optimization plan, to test binding force and internal stress of coatings prepared by optimization solution transformed,to test EDS and DTA curves of coatings prepared at different condition, test the Microhardness of coatings prepared at different condition, observe the micrograph of coatings under different condition,test the Microhardness and XRD pattern of coatings after heat treatment at different temperature, wear the coatings and observe the micrograph of wear scar under different condition.The results revealed that the Ni-P coating prepared by optimization technique and component of solution transformed has eligible adhesion to the substrate and middling hardness,and the surface is compact and smooth, the content of phosphorus in coating is about 8%(Wt%),and after heat treatment at 400℃,the coating has the highest hardness and best wear resistance.