Formation and characterization of borohydride reduced electroless nickel deposits
TL;DR: In this article, the formation of electroless Ni-B deposits and evaluation of their characteristic properties were studied. And the corrosion resistance of Ni-b deposits, in 3.5% sodium chloride solution, both in as-plated and heat-treated (450°C/1 h) conditions, was also evaluated by potentiostatic polarization and electrochemical impedance studies.
About: This article is published in Journal of Alloys and Compounds.The article was published on 2004-02-25. It has received 136 citations till now. The article focuses on the topics: Electroless nickel & Nickel boride.
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TL;DR: In this paper, the improved Ni-B is discussed in terms of microstructural features, performance properties, coating methodology, and applications, as well as its application and microstructures.
Abstract: Improvements to an Ni-(5–6 wt.%)B coating have resulted in exceptional hardness and wear resistance that meet or exceed many of the performance standards set by hard chromium. Currently, no other bath plating technologies offer properties competitive with hard chromium, including electroless nickel-phosphorous derivatives and older versions of Ni-B. In this article, the improved Ni-B is discussed in terms of microstructural features, performance properties, coating methodology, and applications.
76 citations
TL;DR: In this paper, a comparison of properties of Ni-B and Ni−B-Al2O3 composite coatings in their as deposited states is presented to elucidate the beneficial role of Al2O-3 addition.
72 citations
15 Dec 2007-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the effect of plating time, size of powder and weight of powder on the deposition of Ni-P on graphite particles was studied and it was found that by a simple and controlled plating method a uniform and continuous layer of nickel could be deposited on the surface of graphite particle.
Abstract: Electroless deposition technique was used to coat Ni–P on graphite particles with high deposition rate and bath stability by activating the graphite powder in a furnace at 380 °C for 1 h. The effect of plating time, size of the powder and weight of the powder were studied. It was found that by a simple and controlled plating method a uniform and continuous layer of nickel could be deposited on the surface of graphite particles. Scanning electron microscopy images and EDS spectra before and after electroless nickel plating confirm that nickel is deposited on the surface of graphite particles. The rate of increase in weight percent nickel over graphite decreases with time and reaches a plateau. Further increase in weight is attained by plating the same powders in a fresh bath to obtain desired Ni–P alloy mass.
70 citations
TL;DR: In this paper, the authors compared the corrosion resistance of ED Ni-B and Ni−B−Si3N4 composite coatings with its plain counter part using X-ray diffraction measurements and scanning electron microscopy (SEM).
70 citations
TL;DR: Nanocrystalline electroless nickel-boron deposits were synthesized on mild steel (St-37 ASTM A36) substrates and submitted to heat treatment under non-reactive atmosphere to enhance their properties as discussed by the authors.
Abstract: Nanocrystalline electroless nickel-boron deposits were synthesized on mild steel (St-37 ASTM A36) substrates and submitted to heat treatment under non-reactive atmosphere to enhance their properties. Their mechanical and tribological properties were investigated by various methods including nanoindentation, Taber wear testing and scratch tests. Their structural properties were also studied. The hardness of the deposits increased from 900 to 1250 hv 25 due to optimal crystallization of the nanocrystalline coating while the Taber wear index was halved after heat treatment. The scratch tests resistance of the coatings was good in both as-deposited and heat treated conditions. The mechanisms inducing the modification of the mechanical and tribological properties were discussed and they were linked to the structural state of the material.
69 citations
References
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Book•
01 Jan 1990
TL;DR: The Electroless Plating: Fundamentals and Applications (ESPA) as discussed by the authors is a comprehensive text that covers both fundamental and applied aspects of electroless deposition, and was first introduced at SUR/FIN '91.
Abstract: Many texts have been written on surface finishing over the years that deal with electroless deposition as a sidelight. Through the talents and efforts of Glenn Mallory and Juan Hajdu, a comprehensive text, entitled Electroless Plating: Fundamentals and Applications, is available through AESF Headquarters. The editors have combined the efforts of 27 contributing authors to produce a wide-ranging text that covers both fundamental and applied aspects of the subject. Published by the AESF, the book was first introduced at SUR/FIN ‘91—Toronto.
963 citations
Patent•
23 Sep 1968
TL;DR: HIGH STABILITY, AUTOCATALYTIC ELECTROLESS NICKEL PLATING BATH COMPRISING an AQUEOUS SOLUTION CONTAINing about 0.08-016 MOLE/LITER NICKels IONS, about 019-0.38 MOLE / LITER HYPOPHOSPHITE IONS and ESSENTIALLY about 035-3.14 MOLE or Liter CITRATE IONS as discussed by the authors.
Abstract: HIGH STABILITY, AUTOCATALYTIC ELECTROLESS NICKEL PLATING BATH COMPRISING AN AQUEOUS SOLUTION CONTAINING ABOUT 0.08-016 MOLE/LITER NICKEL IONS, ABOUT 0.19-0.38 MOLE/ LITER HYPOPHOSPHITE IONS, AND ESSENTIALLY ABOUT 0.35-3.68 MOLE/LITER AMMONIUM IONS, ABOUT 0.0.-1.07 MOLE/LITER ACETATE ION AND ABOUT 0.007-0.14 MOLE/LITER CITRATE IONS, THE SOLUTION HAVING A PH IN THE RANGE OF ABOUT 7.0 TO ABOUT 9.5 THE AMMONIUM IONS COMPLEX PALLADOUS IONS INTRODUCED INTO THE PLATING BATH BY "DRAG OUT" FROM THE ACTIVATOR SOLUTION TO FORM A SOLUBLE AMMONIUM-PALLADIUM COMPLEX, WHICH INHIBITS REDUCTION OF PALLADOUS ION TO ZERO VALENT CATALYTIC PALLADIUM BY THE HYPOPHOSPHITE OF THE BATH. BY THE REMOVAL OF POTENTIAL CATALYST SITES FROM THE BATH OR BY RENDERING THE POTENTIAL SITES RELATIVELY CATALYTICALLY INACTIVE, RANDOM DEPOSITION OF THE NICKEL AND PREMATURE LOSS OF THE BATH IS AVOIDED.
154 citations
TL;DR: In this paper, the same fundamental reaction is occurring on all the coatings of the present study but over a different effective area in each case, which can be attributed to the decrease in the effective metallic area prone to corrosion.
Abstract: Electroless Ni-P composite coatings have gained a good deal of popularity and acceptance in recent years as they provide considerable improvement of desirable qualities such as hardness, wear, abrasion resistance, etc. The disagreement among researchers on the corrosion behaviour of these coatings warrants a thorough investigation. Among the various techniques available for the determination of corrosion resistance, electrochemical impedance spectroscopy (EIS) is considered to be superior as it provides not only an assessment of the corrosion resistance of different deposits but also enables the mechanistic pathway by which the deposits become corroded to be determined. The present investigation focuses on the evaluation of the corrosion resistance of electroless Ni-P and Ni-P-Si3N4, Ni-P-CeO2 and Ni-P-TiO2 composite coatings produced using an acidic hypophosphite-reduced electroless nickel bath, using EIS. The study makes evident that the same fundamental reaction is occurring on all the coatings of the present study but over a different effective area in each case. The charge transfer resistance of electroless Ni-P and Ni-P composite deposits are in the range 32,253–90,700 Ω cm2, whereas the capacitances of these coatings are in the range 11–17 µF/cm2. The improved corrosion resistance obtained for electroless Ni-P and Ni-P composite coatings is due to the enrichment of phosphorus on the electrode surface, which enables the preferential hydrolysis of phosphorus over that of nickel. The better corrosion resistance obtained for electroless Ni-P composite coatings can be ascribed to the decrease in the effective metallic area prone to corrosion. Among the three electroless Ni-P composite coatings, the corrosion resistance is in the following order: Ni-P-CeO2=Ni-P-Si3N4>Ni-P-TiO2.
119 citations
TL;DR: In this paper, the effect of phosphorus on the corrosion behavior of electroless nickel-plated mild steel in deaerated 40 w/o NaOH solution was examined using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) techniques.
Abstract: Electroless Ni-P deposits with phosphorus content ranging from 4.8 to 12.8 weight percent (w/o) were examined using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) techniques to characterize the effect of phosphorus on the corrosion behavior of electroless nickel-plated mild steel in deaerated 40 w/o NaOH solution. Anodic polarization of the electroless Ni-P alloys in caustic NaOH solution shows that the passive current density decreases with increasing phosphorus content in the deposits. At an applied potential of -1.2 V vs. saturated calomel electrode (V SCE ) (close to their E corr ), EIS data indicate that the R ct for Ni-P alloys in NaOH solution increases with increasing phosphorus content. X-ray photoelectron spectroscopy (XPS) results suggest that the primary constituent formed on the Ni-P surface after EIS measurement in 40 w/o NaOH solution at an applied potential of -0.4 V SCE (in the passive region) is Ni(OH) 2 , which is responsible for the passivity of the Ni-P alloys. The polarization resistance of Ni-P alloys in NaOH solution at -0.4 V SCE also increases with increasing phosphorus content
111 citations