Electrodeposition, structure and properties  of a composite covering «nickel — titanium carbide»

Metallurgy and Materials

Electrodeposition conditions, structure, as well as physical and mechanical properties (microhardness, coupling with a basis, internal tension, wear resistance, corrosion currents) of galvanic composite coverings on the basis of nickel with nanopowder (NP) of titanium carbide (dimensional range (0,02 — 0,08 microns)) and its micropowder (MT) (1 — 5 micron) are investigated. It is established that at electrodeposition of nickel from electrolyte — suspension metal nickel at first is besieged on the nanoparticles weighed in electrolyte, then nanoparticles are strongly attached to a substrate, easily and evenly growing into a deposit. Unlike micropowder, nanopowder of carbide is not only a filler, acting as a strong structure-forming agent in the course of electrocrystallization of nickel and providing its mass multigerminal character that leads to formation of coverings with small sizes of structural fragments, characteristic opaque color, almost pore-free with the increased physical and mechanical properties. The coverings contain, %: Ni — 97,39; O — 1,79; Ti — 0,65; C — 0,17. Annealing of the coverings in vacuum promotes the increase of their coupling with a basis by 1,3 times, microhardness by 1,2 times, wear resistance by 1,3 times. Covering Ni — NP TiC can be recommended for anticorrosive protection and hardening of the details working very hard at average district speeds and low specific loadings.