Az61 Magnesium Alloy Electroless Nickel Plating And Anodizing

This dissertation was aimed at improving the surface performance of the magnesium alloys with two methods, electroless nickel plating (EN) and anodization. EN could greatly improve the rigidity and corrosion resistance of the magnesium alloys, while anodization was fit for conditions that did not ask for high rigidity and corrosion resistance.Main work, experimental methods and results were separately recounted as follows:1. Pretreatment for ENEN for magnesium alloys needs pollutive pretreatment and special plating solution because of their high chemical activities. Full factorial test was adopted to choose the better pretreatment from kinds of processes, and new low pollutive pretreatment was proposed to the question. Effect of pretreatments was evaluated with EN deposits following corresponding pretreatments. The results showed that rigidity and corrosion resistance of EN deposit following new pretreatment proposed in the dissertation was almost the same as that of deposit following pretreatment mentioned in literatures. While, the new pretreatment did not contain high pollutant CrO₃ and HF.2. Analysis of plating processMeans of analyzing EN bath components were confirmed from several analytical methods. Bath system for EN on magnesium alloys was examined real-time. According to the bath examination and other test results, kinds of reactions during plating were analyzed synthetically.The results and analysis of plating process indicated that the virtual value of NaH₂PO₂·H₂O was about 35% when the EN on magnesium alloys was on the rails, approaching to the value of other EN systems, which showed that EN on magnesium alloys in nickel carbonate system obeyed the ordinary hypophosphite EN rule. At the end of 4th period new bath or relevant components should be complemented in time to keep plating normally on, as the virtual value of NaH₂PO₂·H₂O fell to 21.5% in 5^th period of plating bath. Here accumulative total of sample area to bath volume was 2.4 dm²Â·L^-1.3. EN deposit performance and the effect factors analysisDiffraction diagrams of EN deposits were obtained with X-ray diffractomatry...