| Because of the large quantity on the earth and excellent features, magnesium have been paid more and more attention. With the advancement of the technology, the reduce of the cost, the improvement of molding technology and the increased quality of the material, especially the more attention to saving resource and reducing pollution, magnesium alloys have showed its evident superiority among the light materials for it can be continuously developed. So it is a desirable industrial material in our modern world and has been widely used in many fields, such as making automobiles, aerospace, communication equipment, domestic electricity and manufacturing computers. But its chemistry property is very active with its low electrode potential level(-2.36V SCE),so it has a poor corrosion resistance, and even at the room temperature it can be oxygenated by the air. Though it has the oxygenated film, the film is not so deliver to protect itself. It can't be used in many circumstances, for it can be badly eroded in wet conditions, seawater, freshwater and most of organic acid, inorganic acid and salt. When the second phase impurity element formed electro-mate with magnesium, the erosion can be much worse. So it's very important to improve magnesium's resistance to corrosion. In this paper, Mg-xZn-yAl is used as the substrate, which is widely used in the magnesium alloy, we analyzed the effect of component and structure in electroless plating, as well as the effect of plating parameters on Mg-8Zn-4Al and the structure feature of plating.Using the perpendicularity experiment, observing the base, XRD, SEM., EDS, micro-rigidity, and salt corrosion experiment, we studied the effect of the component and structure of Mg-xZn-yAl in the process, the influence of plating parameters on Mg-8Zn-4Al, and the feature of the plating structure.The bath components are various and the plating parameters are complex, but themost important is the main salt, reductants, complex agents, temperature and PH value. And the influence is mainly on the solution stability and deposition rate. The experiment on the Mg-8Zn-4Al base indicated that, (1) Ni2+ and (H2PO2)- are the mostly component in solution, they effect the solution stability and deposition rate. The experiment indicated that the best amount of Ni2+ is 10-18g/L, the best ratio of Ni2+ and (H2PO2)- is 0.3-0.5. (2) Complex agents play a importance role in the solution. The choose of complex agents bases its stability constant. The effect of single complex agents is difficult to purpose. The experiment indicated that the double complex agents have the best impression. The best amount of C3H6O3 and C6H8O7 system is C3H6O3:13-16mL/L , C6H8O7:4.5-5.5g / L .(3) The PH value is high, the NiHPO3 deposits are separate out, the stability of solution is bad. Indicated of the experiment, the best effect of PH value is 5.5-6.5 in solution. (4) The start of electroless need temperature. When the temperature is low, the plating rate is low, and the deposit can even not be carried out, but high temperature can make the solution instability; the coating of Ni-P is bad. So we should stabilize keep temperature is 90 5 C. In the orthogonal test, we studied NaH2PO2 4H2O and two complex agents, which showed that the correct quantity of the solution components can assure desirable plating effect and good plating quality.Mg-xZn-yAl is used as base, we found in the process that the component and structure of the substrate can effect the initial deposit of Ni2+. The electrode potential level of the element in the alloy is different, and the base with more alloy element decides the position of initial deposit; Mg-8Zn-4Al has more alloy element and more complex base, so it can acquire rapid plating rate. When magnesium alloy is solid-dissolved, the distributing of alloy element in the substrate can be average, without the evident phenomenon of multivariant base, the deposit of Ni2+ is relatively equality, and the plating rate is slowed evidently.In spite of base, the coating of Ni-P is close. With the best se...
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