https://pureadmin.qub.ac.uk/ws/files/126683921/Edited_sudagar_R1.pdf

Electroless nickel, alloy, composite and nano coatings – A critical review

This review outlines the development of electroless Ni–P composite coatings. It highlights the method of formation, mechanism of particle incorporation, factors influencing particle incorporation, effect of particle incorporation on the structure, hardness, friction, wear and abrasion resistance, corrosion resistance, high temperature oxidation resistance of electroless Ni–P composite coatings as well as their applications. The improvement in surface properties offered by such composite coatings will have a significant impact on numerous industrial applications and in the future they will secure a more prominent place in the surface engineering of metals and alloys.

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Electroless Ni-P composite coatings

Since the inception of electroless coating by Brenner & Riddell in 1946, it has been the subject of research interest and, in the past two decades, emphasis has shifted to the studies of its properties and applications. The co-deposition of paniculate matter or substance within the growing film has led to a new generation of electroless composite coatings, many of which possess excellent wear and corrosion resistance. This valuable process can coat not only electrically conductive materials including graphite but also fabrics, insulators like plastics, rubber etc. The low coating rates with these can provide better reflectivity of plated surfaces and many more applications. Coatings can be tailored for desired properties by selecting the composition of the coating alloy/composite/metallic to suit specific requirements. The market for these coatings is expanding fast as the potential applications are on the rise. In the present article, an attempt has been made to review different electroless alloy/composite coatings with respect to bath types and their composition, properties and applications. Different characterisation studies have been conducted on various electroless nickel-based coatings with emphasis on wear and corrosion properties.

Electroless alloy/composite coatings: A review

Grain size and grain-boundary effects on diffusion and trapping of hydrogen in pure nickel

Mechanical properties and wear and corrosion resistance of electrodeposited Ni-Co/SiC nanocomposite coating

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

Study of the electrochemical permeation of hydrogen in iron

This work consists of the realization and characterization of composite coatings of Ni–PTFE carried out by electroless deposition on the one hand and electrolytic deposition on the other hand, obtained by pulsed current (CPS) and d.c. current (DC). The evolution of some properties of these coatings generated by various procedures, properties such as morphology, hardness, ductility and wear resistance, are highlighted.

Electrolytic and electroless coatings of Ni–PTFE composites: Study of some characteristics

A size study of the particles in electroless nickel composite deposits was carried out in order to obtain information about the inclusion of silicon carbide (SiC) particles in the deposits. The surfaces and the metallographic cross-sections of the composite deposits were studied under a scanning electron microscope. The metallographic cross-sections of the composite deposits were analysed by observation under an optical microscope, coupled with the technique of image analysis and its data processing software. The results obtained indicated that the particles which are incorporated best are those which are well dispersed in the bath and whose size is smallest.

M. Rezrazi

Papers

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

Study of the electrochemical permeation of hydrogen in iron

Electrolytic and electroless coatings of Ni–PTFE composites: Study of some characteristics

Some morphological characteristics of the incorporation of silicon carbide (SiC) particles into electroless nickel deposits

Study of the electroplating mechanism and physicochemical proprieties of deposited Ni-W-Silicate composite alloy