Wear performance of co-electrodeposited cermet coatings

In this paper, the wear behaviour of nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in nickel matrix produced by co-electrodeposition is investigated. The effects of particle concentration in electrolyte solutions and current density on wear performance of coatings were studied using sliding wear tests. The increases in the wear depth versus sliding distance as a function of loads were recorded and wear track were investigated using SEM and microhardness. The analysis of element maps showed that the volume fraction of each type of dispersed particle in the nickel matrix corresponded to the concentration of that particle in the electrolyte solutions. The increase in hardness of cermet coatings compared to pure form of nickel was explained by the "rule of mixture" and was correlated to grain refining and dispersion strengthening mechanisms which can take place during electrodeposition. The results showed that the coatings with higher Al2O3 in the matrix provide greater hardness and as a result, an improved wear performance against sliding wear can be expected. In addition, changes in wear rate and wear mechanisms during the course of sliding were observed and correlated to the effects of surface strain hardening and fatigue wear under different applied loads. (C) 2013 Elsevier B.V. All rights reserved.