Influence of particle size on the microstructure, hardness and corrosion resistance of electroless Ni–P–Al2O3 composite coatings
TL;DR: In this paper, high phosphorus electroless nickel bath has been used to prepare composite coatings containing alumina powders (50 nm, 0.3 μm and 1.0 μm).
Abstract: High phosphorus electroless nickel bath has been used to prepare composite coatings containing alumina powders (50 nm, 0.3 μm and 1.0 μm). Deposits were characterized for its structure, morphology and hardness. Incorporation of particle has a marginal influence on the composition. More amount of particle incorporation and uniform distribution was found in composite coatings obtained with 1.0-μm (C3) alumina particles compared to 50-nm (C1) and 0.3-μm (C2) alumina particles. XRD results showed a broad peak of nickel and low intensity alumina peaks present in C3 composite coating in as-plated condition. A marginal improvement in hardness was noticed in as-plated composite coatings. A 15% increase in microhardness was observed in the heat-treated (400 °C for 1 h) composite coatings. Potentiodynamic polarization measurements made on these deposits in 3.5% sodium chloride solution showed that uniform corrosion occurred in C1 and C2 composite coatings whereas localized corrosion was observed in C3 composite coating.
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TL;DR: In this article, hardness and wear resistance of two types of electroless coating have been investigated including Ni-P and Ni−P-Al 2 O 3 coatings, which were applied on AISI 1045 steel discs by electroless deposition process and then they were heat treated at 200, 400 and 600°C for 1h.
164 citations
TL;DR: In this article, the Ni-P/DNP nanocomposite coatings were sono-deposited on mild steel through a nickel electroless bath containing ultrasonically dispersed diamond nanoparticles (DNP).
134 citations
TL;DR: In this article, the amount of SiO 2 nano-particles co-deposited in the Ni-P matrix was around 2.5 to 8.5% phosphorus and the X-ray diffraction (XRD) pattern of Ni−P/nano-SiO 2 coating was very similar to that of plain electroless Ni·P coating, whose structure was also amorphous.
130 citations
Cites methods from "Influence of particle size on the m..."
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...% incorporation of nano-alumina particles was obtained after using a surfactant in Ni–P bath with air agitation and also after the addition of 10 g/L Al2O3 nano-particles in the bath [5]....
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TL;DR: In this article, a Ni-P-WC nanocomposite coating was prepared by electroless deposition methods, modifying the typical Ni−P coating through the addition of WC nano-particles.
Abstract: In this study, a Ni–P–WC nanocomposite coating was prepared by electroless deposition methods, modifying the typical Ni–P coating through the addition of WC nano-particles. The morphology, structure, microhardness and corrosion resistance of the Ni–P–WC coating and conventional Ni–P coating were analyzed by using the optical stereoscopic microscopy (OSM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), anodic polarization curve and electrochemical impedance spectroscopy (EIS). It was observed that WC nano-particles and Ni–P deposited homogeneously on the Ni–P matrix, electroless deposited composite coatings exhibit an amorphous structure of the nickel matrix in which crystalline tungsten carbide is incorporated. The microhardness of the coating increased due to the existence of the nano-particles, and it will be improved after heat treatment. According to the results of corrosion testing in the 3.5 wt.% sodium chloride solution, the electroless Ni–P–WC coatings showed significantly improved corrosion resistance due to its special structure, compared to a conventional Ni–P electroless coating, even after 40 days immersion, it also exhibited good corrosion resistance ability.
91 citations
Patent•
03 Aug 2010TL;DR: In this paper, a disk for a hard disk drive is described, which consists of a substrate comprising aluminum and a coating layer disposed over the substrate, and the coating layer comprises an alloy of Ni, X 1 and X 2, wherein X 1 comprises one or more elements selected from the group consisting of Ag, Au, B, Cr, Cu, Ga, In, Mn, Mo, Nb, Pb, Sb, Se, Sn, Te, W, Zn and Zr.
Abstract: A disk for a hard disk drive is provided. The disk comprises a substrate comprising aluminum, and a coating layer disposed over the substrate. The coating layer comprises an alloy of Ni, X 1 and X 2 , wherein X 1 comprises one or more elements selected from the group consisting of Ag, Au, B, Cr, Cu, Ga, In, Mn, Mo, Nb, Pb, Sb, Se, Sn, Te, W, Zn and Zr, and wherein X 2 comprises either B or P, and wherein X 1 and X 2 do not comprise the same elements.
79 citations
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TL;DR: In this article, the effects of CNTs on the tribological properties of these composites were evaluated, and the results demonstrated that the Ni-P-CNT electroless composite coating exhibited higher wear resistance and lower friction coefficient than Ni−P-SiC and Ni-p-graphite composite coatings.
448 citations
TL;DR: In this paper, the authors outline the development of electroless Ni-P composite coatings and highlight the method of formation, mechanism of particle incorporation, factors influencing particle incorporation and the effect of incorporation on the structure, hardness, friction, wear and abrasion resistance, corrosion resistance, high temperature oxidation resistance, and their applications.
Abstract: 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.
359 citations
TL;DR: In this paper, the electroless NiP and Ni-P-X (X 5 SiC, Al2O3 and B) coatings deposited on a heat treatable Al alloy (6063-T6) were investigated.
120 citations
TL;DR: In this paper, the effects of surfactants on codeposition of PTFE particles with electroless Ni-P coating were investigated and a theoretical model was proposed to provide a more deep insight into the codenosition behaviors.
110 citations