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Autori: Lidia Benea
Editorial: Springer Netherlands, Journal of Applied Electrochemistry, 39, p.1671–1681, 2009.
For the purpose of producing new functional surfaces with enhanced tribo-corrosion properties we have investigated the electrochemical co – deposition of composites in which an electrodeposited metal (nickel) is the matrix and a transition – metal oxide (ZrO2) is the dispersed phase. This paper describes the effect of ZrO2 dispersed particles co-deposition on the nickel electrocrystallisation steps as well as the tribocorrosion behaviour of composite coatings obtained. This system was selected because nickel is an industrially important coating material on steel and others support materials. The cathodic polarization curves in electrolytes have been plotted both in the presence and absence of the insoluble dispersed phase. The electrochemical impedance spectroscopy method was used to obtain additional information on the early steps of nickel and nickel matrix composite electrodeposition. The measurements of impedance data was performed with Solartron type electrochemical interface and frequency response analyzer. A schematic co-deposition mechanism is proposed considering the experimental observations. The influence of zirconium oxide on the nickel electrodeposition steps is discussed. The tribocorrosion properties of ZrO2 – Ni composite coatings (100 m thickness) have been studied in 0.5 M K2SO4 solution on a pin on disc tribo-corrosimeter connected to an electrochemical cell. The normal force applied was 10N at a rotation speed of 120 rpm. The counterbody (pin) was a corrundum cylinder (7 mm in diameter), mounted vertically on a rotating head, above the specimen. The lower spherical end (radius = 100 mm) of the pin was then applied against the composite surface (disc).
Cuvinte cheie: straturi compozite, depuneri electrochimice, co-deposition, faza dispersa, tribocoroziune // composite coatings, electrodeposition, co-deposition mechanism, zirconium oxide, dispersed phase, nickel, tribocorrosion