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Journal ArticleDOI

Deposition and properties of electroless Ni–P–B4C composite coatings

22 May 2003-Surface & Coatings Technology (Elsevier)-Vol. 168, Iss: 2, pp 259-262
TL;DR: In this paper, the authors investigated and compared factors affecting the process of electroless deposition of Ni and B 4 C composite coatings and found that an increase in the percentage of the particles in the coating, increases hardness.
Abstract: The present article investigates and compares factors affecting the process of electroless deposition of Ni–P and Ni–P–B 4 C composite coatings. The process of autocatalytic–catalytic reduction of Ni in nickel sulfate and sodium hypophosphate solution with B 4 C suspended particles has been employed in the formation of the electroless Ni–P–B 4 C composite coatings. The concentrations of 1, 2, 4 and 8 g/l of B 4 C in bath were used and resulted in Ni–P–B 4 C electroless coatings with 12, 18, 25, 33 vol.% of B 4 C. Techniques such as SEM, EDAX, optical microscopy and micro-hardness testing were employed to investigate the effect of factors such as thickness, deposition rate and heat treatment cycles on coating properties. Experiments also showed that an increase in the percentage of the particles in the coating, increases hardness. Heat treatment of the electroless composite coatings with 33 vol.% of B 4 C at 400 °C for 1 h in an Argon environment, increased the hardness by 1400 HV.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the Ni-P-ZrO2 composite coatings and multilayer coatings were investigated based on the new electroless plating process and the surface and cross-section morphologies were observed with scanning electron microscopy (SEM).

165 citations

Journal ArticleDOI
TL;DR: In this paper, a self-lubricating Ni-P-MoS2 composite coating has been successfully deposited on a mild steel substrate by electrodeposition, and the effects of MoS2 on the tribological coatings have been investigated.
Abstract: Tribological coatings with low coefficients of friction are in high demand by various industries since they can improve machine efficiency and have an environmental impact. A self-lubricating Ni-P-MoS2 composite coating has been successfully deposited on a mild steel substrate by electrodeposition. The effects of MoS2 on the tribological coatings have been investigated. Compared to a pure Ni-P coating, the Ni-P-MoS2 composite coating exhibited a dramatic reduction in friction coefficient against a bearing steel ball from 0.45 to 0.05. Examination and analysis of the worn surfaces and wear debris, the composite coating showed minimum wear and oxidation compared to the severe wear and oxidation observed in the pure Ni-P coating. The evolution of MoS2 particles in sliding wear has been elucidated.

94 citations

Journal ArticleDOI
01 Jan 2006-Wear
TL;DR: In this article, the wear performance of Ni-P and B 4 C composite coatings was evaluated at 24°C, 35% moisture, 0.164m/s sliding speed and about 1000m sliding distance.

93 citations

Journal ArticleDOI
TL;DR: In this article, Ni-P-TiO 2 nanocomposite coatings with various contents of TiO 2 nano-particulates were prepared by electroless technique from Ni−P plating bath containing TiO2 powder.

93 citations

Journal ArticleDOI
TL;DR: In this article, a comparison of properties of Ni-B and Ni−B-CeO2 composite coatings is presented to elucidate the useful role of CeO2 addition.

85 citations

References
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Book
01 Dec 1991

406 citations

Journal ArticleDOI
TL;DR: In this article, a heat treatment process was used to change the structure of amorphous nickel to Ni3P and fcc nickel by a mechanism similar to that of the solidification of liquid alloys.
Abstract: The structure and properties of electroless nickel are highly sensitive to heat treatment owing to its pronounced metastability. The heat treatment process induces crystallization of amorphous nickel to nickel phosphides and fcc nickel by a mechanism similar to that of the solidification of liquid alloys. The process produces a twofold increase in hardness, the elimination of severe adhesive wear, and a deterioration in the abrasive scratch resistance. The susceptibility of the as deposited coating to severe adhesive wear during unlubricated sliding against plain carbon steel is due to the low interfacial and high surface free energies of the two surfaces, resulting in a high compatibility. Heat treatment removes severe wear by changing the structure from amorphous nickel to Ni3P, which presents a surface incompatible to steel. The abrasive scratch resistance of the as-deposited coating is a result of its relatively high fracture toughness, which is attributable to the absence of heterogeneities i...

55 citations

Journal ArticleDOI
TL;DR: In this paper, the tribological properties for unlubricated sliding wear of Ni-P/diamond composite films with different ceramic contents were evaluated by the pin-on-disk method with different applied loads with Al2O3 countermaterial.

41 citations