The mechanism of growth of porous anodic Al2O3 films on aluminium at high film thicknesses

Patermarakis, G; Karayannis, HS

dc.contributor.author	Patermarakis, G	en
dc.contributor.author	Karayannis, HS	en
dc.date.accessioned	2014-03-01T01:11:33Z
dc.date.available	2014-03-01T01:11:33Z
dc.date.issued	1995	en
dc.identifier.issn	0013-4686	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/11693
dc.subject	aluminium	en
dc.subject	anodic	en
dc.subject	growth	en
dc.subject	mechanism	en
dc.subject	oxide	en
dc.subject	porous	en
dc.subject.classification	Electrochemistry	en
dc.subject.other	AL METAL	en
dc.subject.other	KINETICS	en
dc.title	The mechanism of growth of porous anodic Al2O3 films on aluminium at high film thicknesses	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/0013-4686(95)00250-I	en
heal.identifier.secondary	http://dx.doi.org/10.1016/0013-4686(95)00250-I	en
heal.language	English	en
heal.publicationDate	1995	en
heal.abstract	The mechanism of growth of porous anodic Al2O3, films at various bath temperatures, current densities and H2SO4 concentrations was studied for films produced in a vigorously stirred bath at anodization times higher than those at which the maximum pore diameter behind or at film surface approaches first the cell width. Three cases of film growth were observed: a fluctuating variation, a continuous increase and a case in which a maximum, a minimum and then a continuous increase of mass and thickness successively appear. A method was developed by which alternative, transformed and simplified forms of the developed strict kinetic model governing the growth of porous anodic Al2O3 films, applicable up to the above anodization times, were formulated capable of predicting an approximate pore shape. This pore shape, the concentration of the electrolyte and its variation along pores, the rate of the transport of Al2(SO4)3, produced by the field assisted pore base oxide electrochemical dissolution and the purely chemical pore wall oxide dissolution, and the electrolyte conductivity inside pores were found to be of decisive importance for the growth of oxide beyond these times. Also, suitable models governing the growth of the oxide beyond these times were formulated. In cases where they could apply to the experimental results and observations these were consistent with the predictions of the models. The existence of a maximum limiting constant film mass and thickness was also predicted to occur at specific anodization conditions. © 1995.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Electrochimica Acta	en
dc.identifier.doi	10.1016/0013-4686(95)00250-I	en
dc.identifier.isi	ISI:A1995TA15500011	en
dc.identifier.volume	40	en
dc.identifier.issue	16	en
dc.identifier.spage	2647	en
dc.identifier.epage	2656	en