Structure and performance of electroless composite plating Ni–P–RE and Ti coatings on diamond particles

The Ni–W–P, Ni–P–RE and Ti coatings on diamond surface were prepared by the process of electroless plating and electroless composite plating with heat treatment. The structure of metal plating and coating was tested by scanning electron microscope and X-ray diffraction. The results show that the finer coatings on diamond surface form after electroless plating and electroless composite plating process. The compressive strengths of the coatings increase by 38·57% comparing with the original diamond. The results of X-ray diffraction and thermodynamic analysis indicate that some carbides, such as WC and TiC, have been formed between diamond surface and the coatings after heat treatment. However, the compressive strength of diamonds with electroless composite plating after heat treatment is 16·43% higher than that of uncoated diamond because of high temperature oxidation.