resumo
Rare earth ions are amongst the most promising new generation corrosion inhibitors. This communication describes conditions where, instead of inhibition, acceleration of corrosion occurs after rare earth salts are added to solution. The work was carried out mainly with the Fe-Zn galvanic couple and different rare earth salts, using electrochemical techniques such as galvanic current measurements, scanning vibrating electrode technique and linear sweep voltammetry (polarization curves). The increased activity in the couple is associated to an unexpected cathodic reaction that is observed after adding the salts to solution. The new reaction signifies supplementary oxidant species being reduced at the iron electrode (cathode), accelerating the oxidation of zinc (anode). The nature of this cathodic process is discussed. (C) The Author(s) 2019. Published by ECS.
palavras-chave
SOL-GEL COATINGS; CONVERSION COATINGS; SURFACE MODIFICATION; ALUMINUM-ALLOYS; CERIUM NITRATE; AL-ALLOYS; PROTECTION; HYDROGEN; OXYGEN; STEEL
categoria
Electrochemistry; Materials Science
autores
Oliveira, M; Bastos, AC; Kallip, S; Hack, T; Zheludkevich, ML; Ferreira, MGS
nossos autores
António Alexandre Cunha Bastos
Investigador Auxiliar
Marco Pinheiro de Oliveira
Técnico de Laboratório
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)
Silvar Kallip
Investigador Auxiliaragradecimentos
This work was developed in the scope of the project CICECO - Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. MO thanks FCT for the PhD grant SFRH/BD/117518/2016. ACB acknowledges FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. SK thanks FCT for grant (IF/00856/2013), ETAg for grant PUT1033 and ERA.NET for project RUS_ST2017-477 ACTICOAT.