Abstract  On the basis of electroless Ni-P plating,the techniques of electroless Ni-P-diamond composite plating were studied.The effect of electroless plating solution,the sort and concentration of diamond,the sort and content of surfactant and heat treatment temperature on the micro-hardness of coating was studied through orthogonal design.Results show that the factors affecting the hardness of coating are,in order of significance,sort of diamond,sort of surfactant,heat treatment temperature and content of surfactant.The effect of sort of electroless plating solution as well as the concentration of diamond is slight.The optimal parameters for the best hardness of plating are suggested as,adding nanodiamond and anionic surfactant,heat treatment temperature being 350 ^oC,the content of surfactant being 1:10,using the electroless plating bath B,and the concentration of nanodiamond being 6.0 g/L.

Keywords diamond;electroless composite plating;orthogonal design;micro-hardness