16
M. V. Ved’ et al.
Fig. 1.10 Composition and morphology of a Fe-Co-Mo coating deposited from electrolyte Mo6
at pulse current density, A/dm 2 : (a) 2, (b) 3, (c) 5
identical (Fig. 1.10a, b). Increasing current density to 5 A/dm 2 contributes rising
cobalt and molybdenum content in coatings due to a decrease in the iron portion
(Fig. 1.10c). Variation of current amplitude substantially influences the morphology
of the deposited coatings. The deposits, obtained at current density of 2 A/dm 2 ,
possess fine-grained structure. Separate spheroids are formed on the surface when
increasing i to 3 A/dm 2 , (Fig. 1.10b), and developed globular structure with the
grain agglomerates of diameter ≈2 μm appears at 5 A/dm 2 (Fig. 1.10c), which
agrees with results obtained in [39].
At low current densities of 2–3 A/dm 2 and fixed off-time t off = 10 ms, an increase
in on-time ambiguously affects the composition of a coating. Figure 1.11 shows that
cobalt and iron content in the alloy changes in the range of 4–10 Ãt. %. Maximum
portion of molybdenum ω(Mo) of 12–14 Ãt. % corresponds to t on interval of 5–
20 ms (Fig. 1.11a, b). However, at t on /t off = 50 ms/10 ms, there occurs a sharp
reduction in the content of alloying components (cobalt and molybdenum) in the
coating. Simultaneously, we observe an increase in the iron portion in the alloy up
to 56 Ãt.% (Fig. 1.11a, b).
M. V. Ved’ et al.
Fig. 1.10 Composition and morphology of a Fe-Co-Mo coating deposited from electrolyte Mo6
at pulse current density, A/dm 2 : (a) 2, (b) 3, (c) 5
identical (Fig. 1.10a, b). Increasing current density to 5 A/dm 2 contributes rising
cobalt and molybdenum content in coatings due to a decrease in the iron portion
(Fig. 1.10c). Variation of current amplitude substantially influences the morphology
of the deposited coatings. The deposits, obtained at current density of 2 A/dm 2 ,
possess fine-grained structure. Separate spheroids are formed on the surface when
increasing i to 3 A/dm 2 , (Fig. 1.10b), and developed globular structure with the
grain agglomerates of diameter ≈2 μm appears at 5 A/dm 2 (Fig. 1.10c), which
agrees with results obtained in [39].
At low current densities of 2–3 A/dm 2 and fixed off-time t off = 10 ms, an increase
in on-time ambiguously affects the composition of a coating. Figure 1.11 shows that
cobalt and iron content in the alloy changes in the range of 4–10 Ãt. %. Maximum
portion of molybdenum ω(Mo) of 12–14 Ãt. % corresponds to t on interval of 5–
20 ms (Fig. 1.11a, b). However, at t on /t off = 50 ms/10 ms, there occurs a sharp
reduction in the content of alloying components (cobalt and molybdenum) in the
coating. Simultaneously, we observe an increase in the iron portion in the alloy up
to 56 Ãt.% (Fig. 1.11a, b).