Preparation of Ni-P-diamond coatings with dry friction characteristics and abrasive wear resistance

Abstract

The Ni-P-diamond composite coatings that contained diamond particles with various sizes in microns have been prepared by electroless plating. The effects of diamond particle size and heat-treatment on the microstructure, mechanical properties, dry friction behavior and abrasive wear performance of the Ni-P diamond composite coatings were investigated. It was discovered that a Ni-P diamond composite coating with the thickness of 30μm could be obtained. The diamond particles (2–9μm) could be homogeneously dispersed in the coatings with the volume fractions of 21%–25%. Subsequently to 400°C for 2h of heat treatment, the hardness of the Ni-P diamond coatings increased to approximately 1200HV. The friction coefficients of the Ni-P diamond composite coatings were stable in the range of 0.4–0.52, whereas the Ni-P coating coefficient increased with time and finally reached to beyond 0.50. The addition of diamond particles could improve the wear resistance significantly, whereas as the diamond particle sizes increased, the friction wear resistance and the abrasive wear resistance increased.