Behavior of a Co-Cr-Mo biomaterial in simulated body fluid solutions studied by electrochemical and surface analysis techniques

Abstract

O comportamento do biomaterial Co-Cr-Mo (usado em próteses dentárias) em saliva artificial (AFNOR S90-701), saliva artificial com temperatura e pH modificados e contendo fluoreto foi estudado por técnicas eletroquímicas (potencial de circuito aberto e polarização potenciodinâmica) e de análise de superfície (Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Energia Dispersiva (EED)). Os resultados revelaram que a morfologia da superfície após a polarização potenciodinâmica é heterogênea, exibindo três regiões de composição distinta. Espécies solúveis como CrO 4 2-foram liberadas para a solução durante a polarização. A temperatura e o pH da solução exerceram influência acentuada sobre a cinética de dissolução do biomaterial, enquanto que a presença de fluoreto não alterou as características do sistema.The behavior of a Co-Cr-Mo biomaterial used as dental prosthesis was studied by electrochemical (Open Circuit Potential (OCP) and potentiodynamic polarization) and surface analysis techniques (Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS)) in artificial saliva, artificial saliva with modified temperature (7 ºC -47 ºC) and pH (1.4 -13.4), and containing fluoride (1500 ppm). The results revealed that the surface morphology after potentiodynamic polarization is highly heterogeneous exhibiting three regions of different composition. Soluble metal species such as CrO 4 2-were released to the solution during the potentiodynamic polarization. The electrochemical processes were markedly influenced by solution temperature and pH, whereas the presence of fluoride did not produce changes in the system.

Microstructure, hardness, corrosion resistance and porcelain shear bond strength comparison between cast and hot pressed CoCrMo alloy for metal–ceramic dental restorations

“…Co-Cr alloys have advantages over Ni-Cr alloys like their biocompatibility and the absence of allergic problems as happens with the latter alloys (Roberts et al, 2009). CoCr alloys are also very resistant to corrosion because of chromium (Cr), which forms a protective oxide layer upon the metal's surface (Roberts et al, 2009;Metikoš-Huković and Babić, 2007;Giacomelli et al, 2004;Hsu et al, 2005). Base metal alloys, though, have some drawbacks, namely: higher melting temperatures; require special care in casting procedure because of their high reactivity; and imparts more difficulty to the finishing process because of their higher hardness.…”

Effect of Temperature, Electrolyte Composition and Immersion Time on the Electrochemical Corrosion Behavior of CoCrMo Implant Alloy Exposed to Physiological Serum and Hank's Solution

“…It is important to note that in ~ + 0.65 V, one oxidation peak was observed in the curves from Hank's solution (see, Figure 3). It is likely the oxidation peaks are due to electrochemical reactions involving transitions of chromium to high oxidation states, as described by Giacomelli et al 30 . The electrolyte composition shows influence on the electrochemical corrosion behavior of the CoCrMo alloy.…”

“…At potentials higher than ~ + 0.6 V were observed with an increase in the current density with the potential, for both solutions and temperatures (see Figures 2 and 3). According to Giacomelli et al 30 , the increase of current is due to transpassivation and oxygen evolution reaction. It is important to note that in ~ + 0.65 V, one oxidation peak was observed in the curves from Hank's solution (see, Figure 3).…”

Passivity of Co-Cr-Mo alloys in lactic acid solutions

“…Electrochemical behaviour, composition and solubility of the surface layers, formed on the individual metal components, Co and Cr, in neutral and alkaline solution have been relatively well studied [20][21][22][23][24][25]. However, synergic activity of electrochemical behaviours of these three components differs from their individual behaviour [26][27][28].…”