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1 – 2 of 2This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless…
Abstract
Purpose
This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless Ni-P/Ni-B duplex coating with a thickness of approximately 40 microns.
Design/methodology/approach
Surface characterization of the samples was made by structural surveys (light optic microscope, scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, corrosion and tribocorrosion tests.
Findings
Results of the experiments showed that upper Ni-B coating deposited on the surface of first Ni-P layer by duplex treatment caused remarkable increment in the hardness, corrosion resistance and tribocorrosion performance as compared to the AA7075 aluminum alloy.
Originality/value
This study can be a practical reference and offers insight into the effects of duplex treating on the increase of hardness, corrosion and tribocorrosion performance.
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Keywords
Hamid Omidvar, Mohammad Sajjadnejad, Guy Stremsdoerfer, Yunny Meas and Ali Mozafari
This paper aims to coat ternary composite NiBP-graphite films by Dynamic Chemical Plating “DCP” technique with a growth rate of at least 5 μm/h, which makes this technique a…
Abstract
Purpose
This paper aims to coat ternary composite NiBP-graphite films by Dynamic Chemical Plating “DCP” technique with a growth rate of at least 5 μm/h, which makes this technique a worthy candidate for production of composite films. Electroless nickel plating method can be used to deposit nickel–phosphorous and nickel–boron coatings on metals or plastic surface. However, restrictions such as toxicity, short lifetime of the plating-bath and limited plating rate have limited applications of conventional electroless processes.
Design/methodology/approach
DCP is an alternative for producing metallic deposits on non-conductive materials and can be considered as a modified electroless coating process. Using a double-nozzle gun, two different solutions containing the precursors are sprayed simultaneously and separately onto the surface. With this technique, NiBP-graphite films are fabricated and their corrosion and tribological properties are investigated.
Findings
With a film thickness of 2 μm, tribological analysis confirms that these coatings have favorable anti-friction and anti-wear properties. Corrosion resistance of NiBP-graphite composite films was investigated, and it was found that graphite incorporation significantly enhances corrosion resistance of NiBP films.
Originality/value
DCP is faster and simpler to perform compared to other electroless deposition techniques. Using a double-nozzle gun, metal salt solution and reducing agents are sprayed to the surface, forming a deposit. Previously, coatings such as Cu, Cu-graphite, Cu-PTFE, Ni-B-TiO2, Ni-P, Ni-B-P and Ni-B-Zn with favorable compactness and adherence by DCP were reported. In this paper, the authors report the application of the DCP technique for depositing NiBP-PTFE nanocomposite films.
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