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dc.contributor.authorSanta Coloma, Patricia
dc.contributor.authorIzagirre, Usoa
dc.contributor.authorBelaustegui, Yolanda
dc.contributor.authorJorcin, J.B.
dc.contributor.authorCano, F.J.
dc.contributor.authorLapeña, N.
dc.date.accessioned2016-03-16T10:10:23Z
dc.date.available2016-03-16T10:10:23Z
dc.date.issued2015-08-01
dc.identifier.citationApplied Surface Science 345 (2015) 24–35en
dc.identifier.issn1873-5584en
dc.identifier.urihttp://hdl.handle.net/11556/153
dc.description.abstractNovel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath's formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin Probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an oxidation process occurred in the vicinity of the alloy's intermetallic particles. The amount of the Zr deposits at these locations increased with coating's formulations without Ti, which provided the best corrosion resistance. The Cr-free conversion coatings developed in this study for the AA7075-T6 and AA2024-T3 alloys do not meet yet the strict requirements of the aircraft industry. However, they significantly improved the corrosion performance with respect to the bare alloys and could be a good starting point for further studies and optimization.en
dc.description.sponsorshipBoeing Research & Technology Europeen
dc.language.isoengen
dc.publisherELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSen
dc.titleChromium-free conversion coatings based on inorganic salts(Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applicationsen
dc.typearticleen
dc.identifier.doi10.1016/j.apsusc.2015.02.179en
dc.isiYesen
dc.rights.accessRightsembargoedAccessen
dc.subject.keywordsChromium-free conversion coatingsen
dc.subject.keywordsAluminum alloysen
dc.subject.keywordsCorrosion protectionen
dc.subject.keywordsSalt spray testen
dc.subject.keywordsAFM/SKPFMen
dc.subject.keywordsAeronauticsen


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