CHARACTERISTICS OF COMPOSITE LAYERS Ni/Si3N4

Composite layers with nickel matrix and micro- and nano-sized Si3N4 disperse phase were examined. The layers have been produced by the electrochemical method in Watts bath. In the first case the used Watts bath contained of micro- sized Si3N4 powder and in the second case the Watt's bath has been filled with an organic substance and contained of Si3N4 powder nanoparticles. Investigations of the phase composition of Si3N4 powders are performed (Fig. 1). Figures 2 and 3 show how the presence of the organic substance in the Watts bath influences on structure of nickel layers. Results of morfology examinations of the composite layers are shown in Figure 4. Distributions of Si3N4 phases in nickel matrix are show in Figure 5. Table 2 shows the results of the chemical analysis of the elements building layers. Investigations of the content of the disperse ceramic phase Si3N4 in the material of the composite layers were performed. Results of examinations of the hardness of the Ni and Ni/Si3N4 layers, respectively, are reported (Table 3). Increases of the microhardness of nanocrystalline composi-te layers Ni/Si3N4 with the nanodispersive ceramic phase Si3N4 in comparision with microcrystalline composite layers are identified.