Study On Nickel Nano Sic Particles Composite Electroplating In Supercritical CO₂Fluids

This dissertation was subsidized by the National Natural Science Foundation ofChina (Grant No.51275222), Natural Science Foundation of Jiangsu Province(BK2012585) and the key scientific and technological projects of Changzhou Industry(CE20100045). The experimental researches and analysis of craft process was studied,and it was carried out by supercritical CO2fluids composite electrodepositiontechnology.In allusion to the nature of the nano particles easy reunion, Ni-SiC compositeelectroplating experiment was carried out in the environment of ultrasonic cavitationeffect by ultrasonic dispersion method. A series of composite electroplating tests werecarried with adding micro-nano SiC particles in supercritical CO2fluids byindependent research and development product testing apparatus. The surfaceappearance and the hardness were respectively detected by SEM and digitalmicro-hardness tester. The surface and cross section structure were analyzed bymetallographic analysis system. Finally, these two different preparation methods werecompared based on the performance of composite coatings, and the advantage ofsupercritical CO2fluids composite electrodeposition technology was found.The main process parameters were current density, working pressure, testingtemperature and additive amount of SiC in the test of nickel nano SiC particlescomposite electroplating in supercritical CO2fluids. The parameters that had a greatinfluence on coating performance were searched further on the basis of orthogonaltest analysis. The actual patterns which affect the microhardness and the content ofnano particles in coating were concluded. When the current density was7A dm-2,nano SiC particles content10g L-1, working pressure13MPa, test temperature50℃,the hardness of the coating was950HV approximately which increased above80%than the hardness of the ordinary composite electroplating, nano SiC particles content(percentage by weight) in coating is as high as2.84%.The surface evenness, the hardness and nano SiC particles content in coating whichwere affected by process parameters of the coatings were researched with the analysis results of the orthogonal test. The uniformity advantage of the coatings was attemptedto find by contrastive analysis with the SEM images of the coating surface appearance.The best process method was found to enhance the hardness and the wear resistancewith EDS testing and metallographic analysis.