Experimental Study On Preparation Of W/Ni-P Coated Synthetic Diamond Powder By Chemical Plating

With the rapid improvement of people’s living standards, the requirements of various types of equipment and instruments have become more sophisticated, the superiority of composite materials came to the fore.Because the performance of ternary alloy electroless coating is far superior to binary chemical plating Ni-P coating, and it is more suitable for complex conditions, so ternary alloy plating W-Ni-P have come into being. Through reading a lot of information and thinking, electroless coating is the best way to uniform plating.This selection use the way of electroless plating to prepare W/Ni-P coated synthetic diamond powder. Compared with traditional chemical plating,this experiment firstly plate W coating and then plate Ni-P powder outside the powder-coated, finally W/Ni-P composite powder is successfully prepared. Secondary electroless plating is taken to prepared W/Ni-P-artificial diamond powder, W/Ni-P-artificial diamond powder can fill the gap, the coating can continue thickening, and it is also friendly to the environment. Using SEM and EDS test the quality and composition of the coating. The factors effected thequality of powders is discussed. The granularity and the loosed density of the diamond composite powder are tested by laser particle analyzer and apparent hydrometer. This article gets the following conclusion:1. The results show that coating effect is perfect when the concentration of plating W sodium tungstate 、 hypophosphite 、 trisodium citrate and thiourea respectively are 50g/L、32g/L、24g/L、0.002g/L, the pH and temperature are 8.5 and 90℃.The concentration of plating Ni-P nickel sulfate、hypophosphite、trisodium citrate and thiourea respectively are 35g/L、32g/L、24g/L、0.002g/L, the pH and temperature are 4.5 and 80℃,planting time is 1h.2. The temperature, pH and mass fraction of main ingredients, reducing agent, complexing agent, stabilizer affect the quality of the diamond composite powder. The quality of diamond ternary is best when the above conditions reached certain value.Catalytic activity center appear on the surface of the diamondpowder after sensitization and activationprocess. The metal ions are reduced on the catalytic activity center and then deposited on the surface of the diamond. As the reaction processing the metal coating is thickening constantly.3. Using SEM and EDS test the quality and composition of the coating. The coating combine with diamondfirmly. The coating of W/Ni-P composite powder is uniform and dense. Theprocess of experimental are simple and friendly to environment, and is expected to replacetraditional chemical plating.