Novel approaches on the study of wear performance of electroless Ni–P/diamond composite deposites

The ability to co-deposit particulate matter in a matrix of electroless nickel has led to a new generation of composite coatings. Polycrystalline diamond is one of the many varieties of particulate matter that can be co-deposited. Composite diamond coating is a regenerative layer of diamond particles dispersed in a hard electroless nickel matrix. In this work, experiments have been carried out to study the effect of heat treatment on the wear characteristics of the electroless composite coating containing diamond particles. The results indicate substantial increase in wear resistance after heat treatment. For wear analysis, in order to overcome the difficulties in the most common ‘weight loss’ method, X-ray diffraction method is used. Also the concept of internal standard method of quantitative X-ray diffraction analysis with suitable modifications is employed for the study of removal of diamond particles from the matrix. Superior integrity of the diamond particles with the matrix of the coating is observed for the specimens when heat treated to around 350 °C because of the formation of phosphides. But increasing the heat treatment to about 500 °C affects the wear resistance.