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As technology continues to progress plating, multicomponent chemical electroless nickel plating to become a research focus in this area will enable the development of electroless nickel greatly expand the range of applications. Electroless Ni-P layer has a very nice feature, such as high-strength wear resistance, corrosion resistance, good electromagnetic properties. Also according to the need to achieve the nickel and copper, cobalt, tungsten, chemical co-deposition of the alloy coating to meet high hardness, heat resistance, corrosion resistance requirements, making the electroless Ni-P layer is greatly improved properties can be obtained. Aluminum has low density, high strength, high electrical conductivity, thermal conductivity, easy processing and good corrosion resistance characteristics, it is very suitable for the requirements of the electronics industry light-weight, the aluminum is widely used. However, the aluminum oxide film in acid, alkali corrosive environment, electroless plating Ni-Cu-P layer, both hard and acid, can be a good solution to the shortcomings in this regard. Cu is added to cause crystallization temperature, thereby improving the thermal stability of the coating and weldability. The coating also has good conductivity and low residual magnetism. In particular, as a ferromagnetic material, Co is added Ni-P plating can be improved coercivity, remanence reduction, achieve high corrosion resistance, electromagnetic shielding characteristics and light weight requirements, these are the electronics needed. As plating, process conditions and other factors affect the choice of the coating quality, so this kind of research has become very important. Currently on Electroless Ni-Cu-P's research focuses on the plating process, the plating rate, crystallization behavior, hardness, corrosion resistance, weldability, etc.. c (Cu 2 ) and pH on the activation energy of the magnetic structure and other aspects of the impact is relatively small. There is a low deposition rate, bath unstable plating process pH changes and other issues. And the metallic base on Ni-Co-P electroless plating of a relatively less. We summarize previous work, based on the substrate pre-treatment process, the bath composition and proportion, plating conditions detailed study. Through the film composition, structure, etc. of the analysis, combined with the mechanism of the analysis, the following results. 1 aluminum pre-treatment, the withdrawal of zinc in HNO3 was added HF (1HF 3HNO3) can reduce the interface after a dip zinc residual zinc ions to remove surface impurities certain metal ions to improve adhesion and corrosion resistance. 2.Cu 2 concentration 0.006 mol · L -1 , pH value 8.5 bath stability, plating rate is moderate, the coating quality is good. 3 obtained under the reference bath Ni-Cu-P plating layer, the residual magnetization Mr as low as about 1.0emu / g. 4.Ni-Co-P plating solution, Co 2 / Ni 2 = 1, pH = 9, the resultant coating evenly dense, high hardness, coating at 400 ℃ Heat treatment 1h, coercive force Hc and remanence Mr significantly enhanced.
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