Tribology of electroless nickel coatings – A review

Tribological characteristics of electroless Ni–B coating and optimization of coating parameters using Taguchi based grey relational analysis

High-boron (7–9 wt%) electroless nickel-coatings were synthesized on mild steel substrates by modification of the plating conditions of a mid-boron (5–6 wt% B) plating bath. They were fully characterized and compared when possible with the coatings obtained in the usual operating conditions, before and after a heat treatment at 400 °C for 1 h in a protective atmosphere. The morphology of the coating was similar to mid-boron coatings and left unchanged by heat treatment. Similarly, most properties of the as-deposited coatings were similar for mid and high-boron coatings. However, the effect of heat treatment was very different on both types of coatings: while mid-boron coatings crystallized fully in the Ni 3 B system, high-boron was multiphased. The coatings also presented a difference in terms of hardness behavior with a very important increase for the mid-boron coatings and lesser modification in the case of high boron. The abrasive wear resistance of both kinds of coatings was similar before heat treatment and high-boron coatings had a slightly better behavior after heat treatment. However, the sliding wear behavior of mid-boron coatings is significantly better than that of high-boron electroless nickel.

Increase of boron content in electroless nickel-boron coating by modification of plating conditions

Tribological behavior of electroless Ni–B coatings on magnesium and AZ91D alloy

Electroless nickel boron (Ni-B) coatings are finding their applications in the aerospace, automotive, chemical and electrical industries due to their properties such as high hardness and high wear resistance. However, Ni-B coatings generally show high friction. They also suffered from severe attacks in aqueous solution containing Cl− ion. In this paper, the experiments are carried out to reduce the friction and improve corrosion resistant properties of Ni-B coating by PTFE impregnation. It is found that Ni-B coating after impregnated by an aqueous solution containing 40 wt% PTFE nanoparticles is able to withstand a rubbing test duration of 3600 s with the coefficient of friction as low as

Corrosion and tribological performance of PTFE-coated electroless nickel boron coatings

Electroless deposition process has undergone numerous changes to meet the challenging needs for a variety of industrial applications ever since the invention of the process during 1947. Among the various metals that can be electrolessly plated, electroless nickel has proved its supremacy for producing coatings with high corrosion resistance, hardness, wear resistance and uniformity. Electroless nickel can be deposited from a variety of baths and the coating properties depends upon the type of reducing agents and other deposition conditions. Electroless nickel–boron coatings have received considerable interest nowadays because of the superior hardness, corrosion and wear resistance characteristics. In this paper, the authors have reported on the development of a biodegradable electroless Ni–B bath and evaluated its characteristic properties. The influence of bath constituents, temperature and pH on the rate of deposition was studied. Scanning electron microscopy, X-ray diffraction, X-ray fluoresce...

P.R. Thangavelu

Papers

Studies on development of electroless Ni-B bath for corrosion resistance and wear resistance applications

Carbon-based materials in proton exchange membrane fuel cells: a critical review on performance and application