Abstract
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 85~90°C, nickel sulfate hexahydrate 15~35g/L, sodium hypophosphite 10~30g/L, sodium citrate 5~10g/L, tartaric acid 1~2g/L, pH 3~5, reaction time 30~60min, load factor 1.0~2.0dm<sup>2</sup>/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 80~85%. 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.
Highlights
Amorphous alloy [3, 4] is applied to ultra-rapid cold solidification, during which the atoms cannot be arranged in an orderly manner to crystallize
In 1946, Brenner and Riddel [5, 6] obtained the first electroless Ni-P amorphous coating in a solution consisting of nickel salts and sodium hypophosphite salts, and it was widely used in the PCB [7], cast iron [8], glass microspheres [9, 10], carbon [11], titanium [12], SiC ceramic [13], magnesium alloys [14,15,16], PVC [17]
This paper mainly studies electroless nickel plating on aluminum alloy surface to improve its hardness and corrosion resistance, expand its application range and strengthen its service capability
Summary
Amorphous alloy [3, 4] is applied to ultra-rapid cold solidification, during which the atoms cannot be arranged in an orderly manner to crystallize. T. Bly et al theorized that amorphous alloys could be made from melt quench. Amorphous alloys are a new type of metal materials developed in the 1970s. In 1946, Brenner and Riddel [5, 6] obtained the first electroless Ni-P amorphous coating in a solution consisting of nickel salts and sodium hypophosphite salts, and it was widely used in the PCB [7], cast iron [8], glass microspheres [9, 10], carbon [11], titanium [12], SiC ceramic [13], magnesium alloys [14,15,16], PVC [17]
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