Research On Preparation Of Cu-carbon Powder Composite With Electroplating

Compare with electroless plating, electroplating has the incomparableadvantages, for example, recycling electrolyte, less environmental pollution,relatively simple process, etc. So by the flow electroplating device, plating microngrade material to make its surface deposited a metallic coating, and it has reachedthe purpose of improving the material properties and processing materials moreconveniently, and it is considered to be a highly innovative and practical specialplating method. The laboratory has made copper coated graphite powder materialswhich are of good properties by the flow electroplating device, but there are still aseries of questions to be solved. Therefore, this article, based on the previous studyin the laboratory, makes a further research on flow electroplating. The majorfindings are as follows:(1) Improved the electroplating device. Shortened the distance between theelectrolyte outlet and the cathode board, and improved the collision frequency of thegraphite powder and cathode plate, effectively reduced the deposition amount ofcopper on the cathode plate. Increased the liquid outlet to make the recyclingproducts become more convenient, reduced the loss of electrolyte and product in therecovery process.(2) The electroplating process is improved, the best compositions and operationconditions were obtained.(3) Analyzed oxidation behavior and auxiliary nucleation mechanism of sodiumhypophosphite, found that the oxidation trend of sodium hypophosphite increaseswith increasing temperature, copper sulfate and acetic acid in the electrolyte canpromote the oxidation of sodium hypophosphite also. Hypophosphite can reduceenough copper nuclei on the surface of the graphite powders when hypophosphitecontent higher than3g.dm~3, and act to maintain the content of copper ions in theelectrolyte.(4) Study the role of surfactant in the electrolyte, the appropriate amount ofsurfactant can effectively disperse graphite particles in the electrolyte. Surfactantalso could prevent copper deposited on the cathode plate, and improve the currentefficiency, improve product quality.(5) Using flow electroplating device to fabricating copper coated carbon fibers composite, the copper content of65%and coating evenly could obtain by improvetechnology. The best compositions and operation conditions were obtained.(6) Nickel sulfate as hypophosphite activator in the electrolyte, which couldpromote sodium hypophosphite reduce on the carbon fiber surface.