Effect of phosphorus content on the properties of Ni-P coated diamond

Ni-P coated diamond (NPCD) with different phosphorus content was prepared by electroless plating through adjusting NaH2PO2 concentration in plating bath. Effect of phosphorus content on the properties of NPCD as surface microstructure, phase structure and heat resistance was studied and compared with that of diamond with no Ni-P coatings. The surface microstructure and the chemical composition were determined by environmental scanning electron microscope (ESEM). The phase structure was observed by X-ray diffraction (XRD). The results demonstrated that a lower phosphorus content of NPCD corresponds to better surface properties with lower roughness and higher heat resistance. A higher phosphorus content, on the contrary, leads to worse overall performance of Ni-P coating.