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.

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

Wear behavior of Ni–P and Ni–P–Al2O3 electroless coatings

Effect of surfactants on codeposition of PTFE particles with electroless Ni-P coating

The scope of the present work was to investigate the influence of surface properties of corrugated heat exchanger plates on calcium sulpate crystallization fouling from aqueous salt solutions. The applied surface treatment technologies for the heat exchanger plates are ion beam implantation, ion sputtering, carbo-nitriding & oxidizing, and Ni-P-PTFE coating. Ten pairs of Alfa Laval M3 heat exchanger plates were treated with these techniques and used for this study. Other process parameters such as temperature, solution composition, flow velocity, and the corrugation inclination angle of the plates were kept constant in order to allow for a comparison between the different surface treatments. To evaluate the influence of surface roughness on CaSO4 crystallization fouling, one pair of plates was electropolished. Surface energy and surface roughness measurements were carried out to characterize the treated surfaces.

Influence of Surface Properties and Characteristics on Fouling in Plate Heat Exchangers

Comparison of the coating properties and corrosion rates in electroless Ni-P/PTFE composites prepared by different types of surfactants

The scope of electroless nickel has been increased by codepositing materials such as silicon carbides, ceramics, diamonds and fluoropolymers. This is achieved by taking advantage of different but o...

S. S. Tulsi

Papers

Electroless Nickel-PTFE Composite Coatings