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Journal ArticleDOI

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

01 Apr 2010-Surface Engineering (Maney)-Vol. 26, Iss: 3, pp 153-158
TL;DR: In this paper, the authors have reported on the development of a biodegradable electroless Ni-B bath and evaluated its characteristic properties, and the influence of bath constituents, temperature and pH on the rate of deposition was studied.
Abstract: 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...
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors reviewed the tribological advancement of different electroless nickel coatings based on the bath types, structure and also the tribo testing parameters in recent years.

477 citations

Journal ArticleDOI
TL;DR: In this paper, a taguchi-based grey relational analysis is employed for the optimization of this multiple response problem using an L 27 orthogonal array to minimize the friction and wear characteristics of electroless Ni-B coatings simultaneously by optimizing the three coating parameters.

87 citations

Journal ArticleDOI
TL;DR: In this article, high-boron electroless nickel was synthesized on mild steel substrates by modification of the plating conditions of a mid-bron (5-6-wt% B) plating bath.
Abstract: 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.

70 citations

Journal ArticleDOI
30 Jul 2013-Wear
TL;DR: In this article, Ni-B coatings have been deposited directly on commercial purity magnesium and AZ91D alloy and characterized using glow discharge optical emission spectroscopy, scanning electron microscopy, X-ray diffraction and, for tribological and mechanical evaluation, dry sliding wear and friction testing and microhardness measurement.

68 citations

Journal ArticleDOI
Yong Wan1, Y. Yu1, Lei Cao1, M. Zhang1, Jianguo Gao, Caixia Qi2 
TL;DR: In this paper, the experiments are carried out to reduce the friction and improve corrosion resistant properties of Ni-B coating by PTFE impregnation, and it is found that Ni-b coating after impregnated by an aqueous solution containing 40 ¼wt% pTFE nanoparticles is able to withstand a rubbing test duration of 3600 s with the coefficient of friction as low as
Abstract: 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

65 citations

References
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Book ChapterDOI

[...]

01 Jan 2012

139,059 citations


"Studies on development of electrole..." refers background in this paper

  • ...Very high hardness values can be attained by applying appropriate heat treatments to the Ni–B deposit.(3,5,20) Thus, the heat treatment of the Ni–B deposit at 400uC for one hour hardened the deposit to a value of 1102 VHN....

    [...]

Book
01 Dec 1991

406 citations

Journal ArticleDOI
TL;DR: In this paper, the hardness and wear resistance of electroless Ni-B coatings were evaluated using X-ray diffraction (XRD), Leitz microhardness tester and a pin-on-disc wear test apparatus.
Abstract: The present work aims to study the hardness and wear resistance of electroless Ni–B coatings. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni–B coatings. The structure, microhardness and wear resistance of electroless Ni–B coatings, both in as-plated and heat-treated conditions, were evaluated using X-ray diffraction (XRD), Leitz microhardness tester and a pin-on-disc wear test apparatus. XRD patterns reveal that electroless Ni–B coatings are amorphous in as-plated condition and undergo phase transformation to crystalline nickel and nickel borides upon heat-treatment. The microhardness of the electroless Ni–B coatings increases with increase in heat-treatment temperature and exhibit two maxima in the hardness vs. heat-treatment temperature curve. The specific wear rate increases with increase in applied load from 20 to 40 N and at all applied loads, the specific wear rate and coefficient of friction are less for heat-treated electroless Ni–B deposits compared to that obtained for as-plated ones. The wear process of electroless Ni–B coatings is governed by an adhesive wear mechanism.

247 citations

Journal ArticleDOI
TL;DR: The results of scratch tests show that the Ni-B deposits have good tribological properties under external solicitations as discussed by the authors, they are hard, wear and abrasion resistant, and also have good adhesion to the aluminium substrate.
Abstract: Electroless nickel–boron baths reduced with sodium borohydride can be stabilized with various agents such as thallium nitrate or lead tungstate with no fundamental modification of deposition rates and stability. To improve the mechanical properties of electroless nickel–boron deposits, various heat treatments are applied. At low temperatures, no fundamental changes in the deposit structure are observed, only an improvement of adhesion on aluminium substrate. The values of the Knoop microhardness obtained on these heat-treated deposits are near 600 hk 100 . At higher temperatures, structural changes take place and the nickel–boron deposits crystallize. The microhardness rises until 1050 hk 50 for heat treatments at 350 °C for 4 h. A diffusion layer between the electroless nickel deposit and the aluminium substrate appears at high heat treatment temperatures. The results of scratch tests show that the Ni–B deposits, with or without heat treatments, have good tribological properties under external solicitations. They are hard, wear and abrasion resistant, and also have good adhesion to the aluminium substrate.

178 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the possibility of depositing a thick autocatalytic electroless Ni-B plating on aluminium alloys and proposed an alkaline bath containing sodium borohydride as the reducing agent.
Abstract: Light alloys are more and more widely used, notably in aeronautics and the car industry. To improve their superficial properties, they can be covered with a hard and wear resistant protective layer. In this article, we examine the possibility of depositing a thick autocatalytic electroless Ni–B plating on aluminium alloys. We propose an alkaline bath containing sodium borohydride as the reducing agent. The deposition rate is held constant by a regular replenishment of the Ni–B bath allowing a rate of about 25 μm/h. The Knoop microhardness of the Ni–B deposits after the bath reaches about 750 hk100. Appropriate heat treatment can increase the deposit microhardness up to more than 1000 hk100 but must be applied with regard to the substrate properties. The study of these heat treatments will be published in a further paper.

160 citations