Study On Electroless Composite Plating In Ultrasonic Field

Electroless composite plating is the codeposition process of one or several solid particles with metallic coatings based on electroless plating. In order to accelerate plating rate, decrease the operating temperature and disperse the particles more uniformly, electroless composite plating process was studied in ultrasonic field at low temperature. First, the electroless plating process was established by investigating the effects of Ni, H2PO2, stabilizers, especially complex agents on the plating rate and coating's properties.On the base of above research, the ultrasonic effects on electroless composite plating Ni -P/SiC, Ni-P/ Polytetrafluoroeyhylene(PTFE) and Ni-P/SiC-PTFE were studied. The coatings prepared by ultrasonic process were analyzed by scanning electron microscope(SEM) coating porosity Anodic polarization curves, etc.Through examining the factors of SiC electroless composite plating process, such as ultrasonic effects, dispersion method, content of SiC in plating solution and surfactant etc, on the SiC concentration (vol % ) and dispersing properties of coatings, the best process were developed. The results indicated that the Ni-P/SiC composite coatings presented better corrosion resistance and SiC particles dispersing at the aid of the ultrasonic.To the soft particles(PTFE) electroless composite plating process, the sequence ultrasonic operation can make PTFE coagulating, coursing the potential rising and preventing the plating process. However, the new method of cathodic polarization combining with intermittent plating at the aid of the ultrasonic can ensure a stable plating rate and uniform coatings.In the study of the Ni-P/SiC-PTFE electroless composite plating process, it was found that SiC and PTFE particles were codeposition easily if the radius of SiC is not bigger than that of PTFE particle.