Study On Composite Electroplating And Laser Heat Treatment Of Nano-particle Reinforced Ni-Co-Mo Plating On Crystallizer Copper

Crystallizer copper is easy to produce hot crack, wear, and corrosion due to its special working conditions. Improving the surface hardness, wear resistance, self lubricity and prolonging its service life of the crystallizer copper plate has became current urgent requirement. Many nanoparticle reinforced composite platings can achieve this goal very well, and can improve the binding force between the substrate copper and composite platings by the technology of laser surface heat treatment. So, this work has important research significance and application value.In this paper, the nano particles reinforced Ni-Co-Mo composite platings with strong binding force on the crystallizer copper alloy surface were prepared using nickel sulfate, cobalt sulfate and sodium molybdate as main salt, and nano-Al2O3 and nano-BN as reinforced composite particles. New composite electrolyte formula and process parameters were studied. The microstructure, hardness, binding force, abrasion resistance and the composite reinforcement mechanism of composite platings unprocessed and processed by laser were studied using the means of OM, SEM, EDS, XRD, microhardness and friction and wear. The results show that:Based on Ni, Ni-Co plating experiments, Ni-Co-Mo ternary high temperature metal platings were prepared successfully, the Ni-Co-Mo ternary metal plating prepared by optimum process parameters has fine grain, no crack and porosity, and its thickness is 30μm, hardness is 547HV. Using nano composite plating method, under the optimum composite plating process parameters, nano-Al2O3 and nano-BN particles reinforced ternary metal composite plating of Ni-Co-Mo-Al2O3-BN with thickness of 30μm and hardness of 476HV as well as good abrasion resistance were prepared successfully on the surface of copper alloy. In the Ni-Co-Mo-Al2O3-BN composite platings, nano Al2O3 particles play a major enhancing wear resistance role, and nano BN particles play a reduce wear role, which forming double particle reinforced mechanism. The hardness of Ni-CO-Mo-Al2O3-BN composite plating processed by laser under optimum energy density is 509HV, it is higher than that of composite electroplated sample of 476HV, and its wear resistance increased one times. The nano-particles composite platings processed by laser surface treatment can significantly improve the binding force between the composite plating and the copper alloy substrate, which plays an important improving the performance of anti shedding role for composite plating in application of crystallizer copper alloy.