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Nanocomposite coatings are obtained by electrochemical deposition of silicon carbide nanoparticles (mean diameter 20 nm) in a nickel plating bath. The influence of nanoparticles on nickel electroplating is studied by electrochemical impedance spectroscopy at cathodic potential, and cathodic polarization diagrams are performed in the electrolyte with and without nanoparticles. We show that incorporation of 20 nm SiC particles into nickel deposits modifies the impedance and cathodic polarization diagrams in correlation with the modification of the surface morphology and crystallinity of the nickel matrix. © 2001 The Electrochemical Society. All rights reserved.

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Advances in materials' performance often require the development of composite systems, of which coated materials are one form. The abrasion and corrosion resistance of components can be greatly increased by protective coatings and this is a growing industry of considerable economic importance. This paper aims with a comparative wear corrosion study of pure nickel and Ni‐SiC nano structured composite coating. All the experiments concerning the effects of the rotation speed and the applied load on the corrosion behaviour and friction coefficient were carried out using the 0.5 M Na2SO4 neutral solution. The Ecorr values measured at different disc rotation speeds and different friction loads show some differences between the two types of coatings. For wear corrosion tests an apparatus constructed in the Electrochemistry Laboratory, Dept. of Materials Engineering of Trento University was used. A PMMA cell contained the test solution and a transmission shaft with the tested sample, in the shape of a disc (diameter 40 mm and height 18 mm), connected to an electrical motor. A moving rod held an alumina parallelepiped counterface and the imposing load system thus obtaining a sliding type wear system.

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This paper presents a study of the influence of chemical composition and microstructural changes on the caustic stress corrosion resistance of Inconel 800 alloy (UNS N08800). Slow strain rate tests were performed in deaerated sodium hydroxide solutions (up to 10%), at 350°C, on mill-annealed and sensitized specimens with various aluminum, titanium and carbon contents. The microalloying elements, titanium and aluminum, have been shown to improve the intergranular stress corrosion cracking (IGSCC) performance of the low C (0.03%) materials but did not compensate for the deleterious effect of carbon in the high C (0.06%) heat. Alloys with different metallurgical states, resulting from different manufacturing processes, had similar behavior. A heat treatment at 575°C for 100 hours, producing sensitized structures, was generally detrimental.

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