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Effect of the acid environment on the electrochemical behaviour of 1045 steel r...

Nóbrega, Ana Cecilia Vieira da; Rocha, L. A.; Avila, E. A.; Martinelli, A. E.; Melo, D. M. A.; Sá, Maria das Vitórias Vieira Almeida de

External corrosion is one of the most common causes of oilwell casing failure. Hostile environments can be due to acidizing treatments. Although it is common to add corrosion inhibitors and oxygen scavengers in acidic solutions to control external casing corrosion, their real efficiency is unknown yet. Therefore, it is important to establish how aggressive to steel are the different hostile environments to help...


Corrosion behaviour of titanium in the presence of Streptococcus mutans

Souza, J. C. M.; Ponthiaux, Pierre; Henriques, Mariana; Oliveira, Rosário; Teughels, W.; Celis, J. P.; Rocha, L. A.

Objective The main aim of this in vitro study was to evaluate the influence of Streptococcus mutans on the corrosion of titanium. Methods S. mutans biofilms were formed on commercially pure titanium (CP-Ti) square samples (10 mm × 10 mm × 1 mm) using a culture medium enriched with sucrose. Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements were used to evaluate the cor...


Simultaneous degradation by corrosion and wear of titanium in artificial saliva...

Souza, J.C.M; Barbosa, S. L; Ariza, E.; Celis, J-P.; Rocha, L. A.

Article in press ; The degradation of titanium-based oral rehabilitation systems can occur by corrosion and wear processes taking place simultaneously (tribocorrosion) and influenced by the presence of fluorides. In this study, the tribocorrosion behavior of titanium in artificial saliva solutions containing fluorides is investigated. Before sliding tests were started up, electrochemical measurements such as o...


Comportamento tribocorrosivo de sistemas metalocerâmicos odontológicos de Ni-Cr...

Araújo, A. M. A.; Martinelli, A. E.; Nascimento, R. M.; Melo, D. M. A.; Medeiros, A. L.; Rocha, L. A.; Avila, E. A.

Partial fixed prosthodontic restoration is used to rehabilitate both the form and function of partial or total compromised teeth and must remain permanently joined to the remaining teeth. The most useful material in prosthodontics is feldspar porcelain, commercialized as aluminosilicate powders. Dental porcelains depict limited mechanical strength to rehabilitate extensive spaces. The association of porcelain w...


Mechanical and electrochemical deterioration mechanisms in the tribocorrosion o...

Vieira, A. C.; Rocha, L. A.; Papageorgiou, Nikolaos; Mischler, S.

Tribocorrosion of Al-Si-Cu-Mg alloys was investigated in 0.05 M NaCl and 0.1 M NaNO3 solutions under severe sliding and controlled electrochemical conditions. A simple galvanic coupling model was developed to analyze and quantitatively predict the evolution potential of the open circuit potential during tribocorrosion. According to this model and the obtained results, galvanic coupling was established in the Na...


Tribocorrosion behavior of CoCrMo alloy for hip prosthesis as a function of loa...

Mathew, M. T.; Runa, M. J.; Laurent, M. T.; Jacobs, J. J.; Rocha, L. A.; Wimmer, M. A.


Influence of SiC reinforcement particles on the tribocorrosion behaviour of Al–...

Vieira, A. C.; Rocha, L. A.; Mischler, S.

The main aim of this work was to study and understand the influence of SiC particles on the corrosion and tribocorrosion of Al-matrix composite materials. For that, Al–SiCp functionally graded composites were produced by centrifugal casting and different SiCp contents were achieved. Their mechanical properties were improved by age-hardening heat treatments. The tribocorrosion behaviour was studied in 0.05M NaCl...


Vacuum infiltration of copper aluminate by liquid aluminium

Guedes, M.; Ferreira, J. M. F.; Rocha, L. A.; Ferro, A. C.

This paper studies attained microstructures and reactive mechanisms involved in vacuum infiltration of copper aluminate preforms with liquid aluminium. At high temperatures, under vacuum, the inherent alumina film enveloping the metal is overcome, and aluminium is expected to reduce copper aluminate, rendering alumina and copper. Under this approach, copper aluminate toils as a controlled infiltration path for ...


Corrosion behaviour of Al/Al3Ti and Al/Al3Zr functionally graded materials prod...

Ferreira, S. C.; Rocha, L. A.; Ariza, E.; Sequeira, P. D.; Watanabe, Yoshimi; Fernandes, J.C.S.

Intermetallic particles, Al3Ti and Al3Zr were formed in Al–5mass%Ti and Al–5mass%Zr alloys, respectively, by centrifugal casting, in order to create functionally graded materials (FGMs). At present, no information is available on the influence of the amount of intermetallics on the electrochemical properties of these alloys. In this paper, the corrosion resistance of Al/Al3Ti and Al/Al3Zr FGMs was investigated...


Effect of Al2Cu precipitates size and mass transport on the polarisation behavi...

Vieira, A. C.; Pinto, A. M.; Rocha, L. A.; Mischler, S.

The electrochemical behaviour of age-hardened Al–Si–Cu–Mg alloys was investigated in a 0.05 M NaCl solution under controlled mass transport conditions using a rotating disk electrode. This work aimed at getting better understanding of the effect of the alloy microstructure, in particular the size distribution of Al2Cu phase, on the corrosion behaviour of the alloy. Three different size distributions of the Al2C...


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Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia