Mechanical properties comparison of Ni-diamond composite coatings fabricated by different methods

In this paper, three methods were used to fabricate Ni-diamond composite coatings. The first one was the traditional co-depositing technique, by which, the Ni-diamond coating were electrodeposited from a Watts-type bath containing diamond particles in suspension. The second was called sediment co-deposition. And the difference between the traditional and sediment co-depositions was changing the vertically arranged electrodes in electroplating pool to a horizontal placement with the anode kept above. To enhance the particle content in the composite coatings, a method of burying co-deposition was introduced and the arrangement of the electrodes (horizontal placement) was the same as the sediment co-deposition. Before plating, the electrodes rested firstly in plating bath for a period of time to form a thin particle film on the cathode surface due to sedimentation. After that, these particles were buried by metal coating during the plating process. The morphology of surface and cross section, composition, surface roughness, micro-hardness and adhesive strength of the coatings were studied. The wear resistance of the specimens prepared by the different techniques were tested and compared.