Tracer study of pore initiation in anodic alumina formed in phosphoric acid

TY - JOUR

T1 - Tracer study of pore initiation in anodic alumina formed in phosphoric acid

AU - Baron-Wiecheć, A.

AU - Burke, M. G.

AU - Hashimoto, T.

AU - Liu, H.

AU - Skeldon, P.

AU - Thompson, G. E.

AU - Habazaki, H.

AU - Ganem, J. J.

AU - Vickridge, I. C.

N1 - Funding Information: The authors are grateful to the Engineering and Physical Sciences Research Council (U.K.) (Programme Grant: LATEST2 ) for support of this work. They also thank the European Community for financial assistance within the Integrating Activity “Support of Public and Industrial Research Using Ion Beam Technology (SPIRIT)”, under EC contract no. 227012 . In addition, they wish to acknowledge the support of the European Community's Seventh Framework Programme FP7/2007-2013 through the award of a Marie Curie Fellowship to ABW under grant agreement No PIEF-GA-2008-219913 .

PY - 2013

Y1 - 2013

N2 - Arsenic species are utilized as tracers in a study of pore initiation in anodic films that were formed at constant potentials on aluminium in phosphoric acid. The films were grown first in sodium arsenate solution and then in phosphoric acid, and examined using ion beam analysis and scanning and transmission electron microscopies. The analysis of the arsenic content of specimens indicates that the growth mechanisms of incipient and major pores involve mainly field-assisted dissolution and field-assisted flow of the alumina, respectively. The transition between incipient and major pore formation is suggested to be initiated by preferential growth of certain incipient pores, leading to a locally increased current density at the pore bases. The major pores subsequently develop by the flow oxide away from the pore bases, which is evident from the behaviour of the arsenic tracer. The results suggest that the flow is associated with the non-uniform distribution of ionic current and a relatively low volume of formed film material compared with the volume of oxidized aluminium.

AB - Arsenic species are utilized as tracers in a study of pore initiation in anodic films that were formed at constant potentials on aluminium in phosphoric acid. The films were grown first in sodium arsenate solution and then in phosphoric acid, and examined using ion beam analysis and scanning and transmission electron microscopies. The analysis of the arsenic content of specimens indicates that the growth mechanisms of incipient and major pores involve mainly field-assisted dissolution and field-assisted flow of the alumina, respectively. The transition between incipient and major pore formation is suggested to be initiated by preferential growth of certain incipient pores, leading to a locally increased current density at the pore bases. The major pores subsequently develop by the flow oxide away from the pore bases, which is evident from the behaviour of the arsenic tracer. The results suggest that the flow is associated with the non-uniform distribution of ionic current and a relatively low volume of formed film material compared with the volume of oxidized aluminium.

KW - Aluminium

KW - Anodizing

KW - Mechanism

KW - Porous film

UR - http://www.scopus.com/inward/record.url?scp=84886132925&partnerID=8YFLogxK

U2 - 10.1016/j.electacta.2013.09.060

DO - 10.1016/j.electacta.2013.09.060

M3 - 文章

AN - SCOPUS:84886132925

SN - 0013-4686

VL - 113

SP - 302

EP - 312

JO - Electrochimica Acta

JF - Electrochimica Acta

ER -