Hardness, friction and wear characteristics of nickel-SiC electroless composite deposits

Composite coatings constitute a new class of materials which are mostly used for mechanical and tribological applications. Among these materials, nickel deposits with incorporation of hard ceramic particles such as silicon carbide (SiC), combine anti-corrosion properties (due to the presence of nickel), with mechanical and tribological performances (due to the presence of particles of SiC). In the present study, electroless Ni–SiC composite deposits with various amounts of SiC have been prepared and characterized. The first part of this paper considers the materials, the experimental conditions and the characterization of the coatings. The second part is dedicated to the study of the mechanical (hardness) and tribological (friction resistance and wear) properties of the co-deposits. Friction tests were carried out using a ball on disk tribometer. The mechanisms of wear were analysed from observations of the wear scars and their characterization using two-dimensional and three-dimensional profilometry. The results show that increasing the size or the rate of SiC particles incorporated lead to an increase in both the hardness of the films and friction coefficient when sliding against a steel ball.