resumo
In a quest for a better understanding of the mechanism and contribution(s) of fresh (un-degraded) and degraded CFRP surfaces to galvanic corrosion of coupled metals in multi-material assemblies the electrochemical behaviour of CFRP in quiescent 50 mM NaCl was studied using electrochemical techniques. Tests using ferricyanide/ferrocyanide redox couple revealed a quasi-reversible behaviour. Under cathodic polarization, CFRP is active electrochemically evidenced by the increase in pH (to pH >= 10). Galvanic current densities and potentials for Al-CFRP couple comprised of freshly polished CFRP sample ranged from 15-25 mu A cm(-2) and approximate to-660 to -850 mV(SCE) respectively, while the corresponding parameter for Al-CFRP couple comprised of degraded CFRP were in the range 10-25 mu A cm(-2) and approximate to-670 to -900 mV(SCE). Contrary to expectations, CFRP prior exposure to degradative high pH media before galvanic coupling did not result in an increase in the intensity of galvanic corrosion of the coupled metal.
palavras-chave
ELECTROLYTE FILM THICKNESS; LINEAR SWEEP VOLTAMMETRY; MICROELECTRODE ARRAYS; OXYGEN REDUCTION; MICRODISK ELECTRODES; GALVANIC CORROSION; COMPOSITES; POLARIZATION; INTERFACE; GRAPHENE
categoria
Materials Science
autores
Ofoegbu, SU; Quevedo, MC; Bastos, AC; Ferreira, MGS; Zheludkevich, ML
nossos autores
António Alexandre Cunha Bastos
Investigador Auxiliar
Marcela Citlalim Quevedo Reyes
Bolseiro de pós-Doutoramento
Mário Guerreiro Silva Ferreira
Professor(a) Jubilado(a)
Stanley Udochukwu Ofoegbu
ColaboradorProjectos
Corrosion adn corrosion protection in multi-material systems (PTDC/CTM/108446/2008)
PROAIR - Active PROtection of multi-material assemblies for AIRcrafts (PROAIR)
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
agradecimentos
Funding from FCT project: Corrosion and Corrosion Protection in Multi-material Systems, (PTDC/CTM/108446/2008), and European FP7 project: Active PROtection of multi-material assemblies for AIRcrafts [PROAIR (PIAPP-GA-2013-612415)] are acknowledged. S.U.O. acknowledges FundacAo para a Ciencia e a Tecnologia (FCT) Portugal for doctoral (SFRH/BD/75167/2010) grant. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID /CTM /50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work was also supported by the projects UIDB/00481/2020 - FCT - FundacAo para a Ciencia e a Tecnologia; and CENTRO-01-0145-FEDER-022083 - Centro Portugal Regional Operational Programme (Centro2020), and POCI-OT1-PI 1.2-TI 47-FEDER-033912-Competitiveness and Internationalization Operational Program, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund.