Technology Improvement of Electroless Plating Ni-P Alloy Coating on SiCP/Al Composite Surface

The zinc dipping pre-process was applied on SiCP/Al composites surface, and then a Ni-P alloy coating was prepared on composite surface by alkaline pre-plating and acid plating. The microstructure and properties of the coating were studied by observing morphology, chemical composite analysis, electrochemical test and thermal shock test. The results show that the obvious cell structure was found on the mid-phosphorous coating prepared by the above methods, and the coating was fairy integrated and uniform, and the thickness of the coating was 15-20 μm. The free corrosion potential increased substantially and the passive current density decreased obviously after electroless plating. The bonding strength between the composite and Ni-P alloy plating coating was fairy high.