resumo
In the present work corrosion inhibition in microdefects of protective coatings on magnesium alloy was studied by SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique) in 0.05 M NaCl. Mg2+- and pH-selective microelectrodes were developed to be used by SIET. The microelectrodes were characterized from the standpoint of properties important for corrosion applications, aiming at the reliable functioning during measurements. The combination of SVET and SIET demonstrated to be a useful approach to investigate the inhibition of corrosion processes in microdefects on coated AZ31. In this paper the corrosion inhibiting properties of 1,2,4,-triazole. F- and Ce3+ on AZ31 alloy were analyzed. According to the results, 1,2,4-triazole in concentration of 0.01 M showed the highest inhibition efficiency among the studied inhibitors and was able to prevent the increase of pH in the corroding defects, by keeping the corrosion activity on a very low level during the tested immersion period. (C) 2010 Elsevier Ltd. All rights reserved.
palavras-chave
SODIUM-SULFATE SOLUTIONS; SOL-GEL COATINGS; CONVERSION COATINGS; ALUMINUM-ALLOY; PURE MAGNESIUM; PROTECTION; CERIUM; FILMS; RESISTANCE; NANOPARTICLES
categoria
Electrochemistry
autores
Karavai, OV; Bastos, AC; Zheludkevich, ML; Taryba, MG; Lamaka, SV; Ferreira, MGS
nossos autores
António Alexandre Cunha Bastos
Investigador Auxiliar
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)
Mikhail Zheludkevich
Investigador Principal Convidado
Olga Karavai
InvestigadorGrupos
G1 - Materiais Porosos e Nanossistemas
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
Projectos
agradecimentos
O.V. Karavai and A.C. Bastos thank FCT (Portugal) for PhD and post-doc grants, respectively. Financial support of FCT and FP7 projects is gratefully acknowledged (PTDC/CTM/65632/2006, PTDC/CTM/66041/2006 and NMP3-LA-2008-214261). The authors also thank Prof. J.G. Kunkel (Department of Biology. University of Massachusetts, USA) for the micropipette pulling protocol. Alan Shipley from Applicable Electronics Inc. is gratefully acknowledged for the support and maintenance of our SVET/SIET systems.