An electrochemical evaluation of possible non-chromate conversion coating treatments for electrodeposited zinc-nickel alloys
Wharton, J.A., Wilcox, G.D. and Baldwin, K.R. (1999) An electrochemical evaluation of possible non-chromate conversion coating treatments for electrodeposited zinc-nickel alloys. Transactions of the Institute of Metal Finishing, 77, (4), 152-158.
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A number of possible non-chromate conversion coating formulations have been studied to examine their efficacy as replacements for chromate-based coating treatments on electrodeposited zinc-nickel alloys. Data have been collected from both electrochemical and conventional salt fog corrosion tests. In the latter tests all the alternative non-chromate systems studied delayed the onset of the corrosion of the zinc-nickel coating itself but only the simple molybdate and the permanganate/molybdate dual treatment brought about improvements in times to red rusting of the steel substrate. The electrochemical evaluations suggested that simple molybdate-treated surfaces act as only moderate barriers to the chloride environments. Of the two dual treatments, permanganate/molybdate behaved similarly to the simple molybdate treated surfaces in the electrochemical tests, but the molybdate/permanganate was more protective, although this was not exhibited in the salt fog corrosion tests.
|Keywords:||conversion coating, electrodeposition, metal coating, zinc plating, materials replacement, corrosion resistance, molybdates, permanganates, galvanized steel, carbon steel, zinc base alloys, surface treatment, corrosion potential, sodium chloride, nickel alloy|
|Subjects:||T Technology > TN Mining engineering. Metallurgy|
|Divisions:||University Structure - Pre August 2011 > School of Engineering Sciences
|Date Deposited:||05 Feb 2007|
|Last Modified:||02 Mar 2012 13:26|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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