Tribological properties of Ni/Si3N4 composite leyers
Magdalena Kowalewska, Maria Trzaska Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa
Quarterly No. 2, 2006 pages 32-37
DOI:
keywords: nickel layers, nanocrystalline composite layers, structure, abrasion wear properties
abstract The influence of the structure of Ni/Si3N4 composite layers produced by the electrochemical method on their tribological properties are presented. Investigations concern the composite layers with microcrystalline nickel matrix and micro- sized Si3N4 disperse phase, as well as composite layers with nanocrystalline nickel matrix and nano-sized Si3N4 disperse phase. For comparison purposes also microcrystalline and nanocrystalline nickel layers have been investigated. Morphologies of the phase composition of Si3N4 powders are performed (Fig. 1). Results of morphological and surface forms examinations of the nickel and composite layers are shown in Figures 2 and 3, and in Figures 5 and 6, respectively. Distributions of Si3N4 phase particles in nickel matrix are presented in Figure 4. The roughness of the nickel and composite layers are also studied (Fig. 7). Results of examinations of the hardness of the Ni and Ni/Si3N4 layers are reported (Table 1). The course of wear tests as time functions of duration of attempt of the Ni and Ni/Si3N4 layers are presented in Figure 8. The morphologies of nickel an composite layers and their counter samples after wear tests are shown in Figure 9. Increases of the microhardness of nanocrystalline composite layers Ni/Si3N4 with the nano-sized Si3N4 disperse ceramic phase in comparison with microcrystalline composite layers are identified. In conclusion, it has been checked also that the Si3N4 disperse phase involved into nanocrystalline as well as microcrystalline Ni surface layers importantly decreases their abrasion wear.