Investigations of the wear resistance of nanocrystalline composite coatings Ni-B
Benigna Szeptycka, Anna Gajewska-Midziałek, Daniela Derewnicka Instytut Mechaniki Precyzyjnej, ul. Duchnicka 3, 01-796 Warszawa
Annals 4 No. 11, 2004 pages 288-292
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abstract In present work the nanocrystalline composite electrochemical coatings were prepared with nickel matrix and particles B. The nickel plating bath of low nickel ion concentration (0.76 mol/dm3) containing brightening organic compound with surfactants and the dispersed particle (boron) was used for electrodeposition of composite coatings. The content of particles in coatings was examined gravimetrically. The dependence of the boron content in the composite coatings Ni-B from of the concentration and kind of the organic additives is given in Figure 1. The structure the composite coatings was established using TEM (Figs. 2-4). The roughness of the coatings Ni-B was measured using tester TR 100 (Fig. 5). The microhardness of the deposited layers was measured using a Vickers’ method at a load of 0.01 and 0.05 kG. Figures 6 and 7 shows the microhardness of the composite coating Ni-B. The experiments for Ni-B coatings were made without lubrication and was tested using a technique based on the 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-B in the dependence from of the concentration and kind of the organic additives is given on Figure 8. The results suggest that the effect used of the organic compounds was the increase of the boron contents in the coating and the development of the nanostructure of the nickel matrix. The wear resistance increased with the roughness increase. Key words: nickel, composites, electrochemical coatings, boron