Investigation of the wear resistance of composite coatings Ni-SiC
Benigna Szeptycka, Anna Gajewska-Midziałek Institute of Precision Mechanics, Duchnicka 3, 01-796 Warsaw, Poland
Quarterly No. 2, 2005 pages 7-10
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abstract In present work the composite electrochemical coatings were prepared with nickel matrix and particles SiC. The nickel plating bath of low nickel ion concentration (0.75 M) containing brightening organic compound with surfactants and the dispersed particle (SiC) was used for electrodeposition of composite coatings. The content of particles in coatings was examined gravimetrically. The dependence of SiC content in composite coatings Ni-SiC on the concentration and kind of the organic additives is given in Table 1. The roughness of the coatings Ni-SiC was measured using tester TR 100 (Tab. 1). Siemens D500 X-ray diffractometer with CuKα, radiation was used to determine the dimension of nickel [111] crystallites and microstress (Tab. 1). The microhardness of the deposited layers was measured using a Vickers’ method at a load of 0.01 and 0.05 kG. Figures 2 and 3 show the microhardness of composite coating Ni-SiC. The wear experiments of Ni-SiC coatings were made without lubrication using the technique based on measuring system comprising a flat surface and a ball. On the basis of the wear traces and measurement of their diameter, the depth of the wear was calculated, which was the measure of wear resistance. The wear of the composite coatings Ni-SiC in the dependence from of the concentration and kind of the organic additives is given in Figure 4. The obtained results suggest that the organic compounds used in the experiments had a significant effect on the composition and structure of these coatings. This study has shown that the wear resistance is proportional to the microhardness, the roughness, the size of nickel grain and the particle contents in Ni-SiC coatings. Key words: electrodeposition, nickel, composite, silicon carbide, wearability