A Method for Electroless Nickel Plating on Aluminum Alloy Surface

摘要

According to the following plating processes: deoiling washing pickling washing drying weighing electroless plating washing drying weighing. It can obtain Ni-P deposit on aluminum alloy. It studied the influence of bath composition and process parameters on the composition and deposition rate of the alloy coating. Under temperature of 8590, nickel sulfate hexahydrate 1535g/L, sodium hypophosphite 1030g/L, sodium citrate 510g/L, tartaric acid 12g/L, pH 35, reaction time 3060min, load factor 1.02.0dm~2/L. The microstructure, surface morphology, composition and valence of the elements in the alloy coating were studied by metallographic microscope, SEM, EDS and other modern analytical methods. The size of spherical grain was below 1um and compact distribution. The chemical coatings were mainly composed two elements, which were phosphorous and nickel. The mass percentage of phosphorous was about 15%, and the other one was about 8085%. The corrosion resistance of the alloy coating was studied by CASS [1] test method, through 80h CASS test detection, the protection class of chemical coating can be reached 5. The relevant evaluation criteria can be referred to GB/T 6461-2002 [2]. The results show that the Ni-P binary amorphous alloy can be successfully prepared by this process.