A transport phenomenon analysis criterion predicting pitting appearance during Al anodization in sulphate electrolytes

Patermarakis, G; Moussoutzanis, K

dc.contributor.author	Patermarakis, G	en
dc.contributor.author	Moussoutzanis, K	en
dc.date.accessioned	2014-03-01T01:18:34Z
dc.date.available	2014-03-01T01:18:34Z
dc.date.issued	2003	en
dc.identifier.issn	0098-6445	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15095
dc.subject	Anodizing aluminium	en
dc.subject	Criterion	en
dc.subject	Pitting	en
dc.subject	Transport phenomenon analysis	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	Anodic oxidation	en
dc.subject.other	Charge transfer	en
dc.subject.other	Current density	en
dc.subject.other	Electrolytes	en
dc.subject.other	Film growth	en
dc.subject.other	Mass transfer	en
dc.subject.other	Pitting	en
dc.subject.other	Temperature	en
dc.subject.other	Bath temperature	en
dc.subject.other	Aluminum	en
dc.subject.other	aluminum	en
dc.subject.other	anodizing	en
dc.subject.other	coating	en
dc.subject.other	corrosion	en
dc.subject.other	electrolyte	en
dc.subject.other	film thickness	en
dc.subject.other	pitting	en
dc.title	A transport phenomenon analysis criterion predicting pitting appearance during Al anodization in sulphate electrolytes	en
heal.type	journalArticle	en
heal.identifier.primary	10.1080/00986440302099	en
heal.identifier.secondary	http://dx.doi.org/10.1080/00986440302099	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	The conditions of Al anodizing, bath temperatures, current densities, and concentrations of H2SO4 and Al-2(SO4)(3) in pure H2SO4, and H2SO4 +Al-2(SO4)(3) solutions where the growth of porous anodic alumina films is uniform/regular and nonuniform/abnormal with appearance of pitting, were experimentally determined. The equations describing the mass and charge transport phenomena and the composition of the solution at the pore bases during the regular oxide growth were solved. The current densities at which the H2SO4 concentration becomes minimum at low film thicknesses were determined, which coincided with the experimental ones above which pitting appeared. They increased with the bath temperature and the H2SO4 concentration and decreased with the Al-2(SO4)(3) concentration. A criterion for pitting apearance was thus formulated. It explained the promotion of pitting appearance by the low bath temperatures and H2SO4 concentrations, high current densities, and sulphate additives, which is important for developing methods for producing regularly grown high-quality coatings.	en
heal.publisher	TAYLOR & FRANCIS LTD	en
heal.journalName	Chemical Engineering Communications	en
dc.identifier.doi	10.1080/00986440302099	en
dc.identifier.isi	ISI:000183182700033	en
dc.identifier.volume	190	en
dc.identifier.issue	5-8	en
dc.identifier.spage	1018	en
dc.identifier.epage	1040	en