The aim of this study is to investigate the electrochemical behavior of some dental metallic mate... more The aim of this study is to investigate the electrochemical behavior of some dental metallic materials in artificial saliva for different pH (5.6 and 3.4), NaF content (500 ppm, 1000 ppm, and 2000 ppm), and with albumin protein addition (0.6 wt.%) for pH 3.4. The corrosion resistance of the alloys was quantitatively evaluated by polarization resistance, estimated by electrochemical impedance spectroscopy method. An adaptive k-nearest-neighbor regression method was applied for evaluating the corrosion resistance of the alloys by simulation, depending on the operation conditions. The predictions provided by the model are useful for experimental practice, as they can replace or, at least, help to plan the experiments. The accurate results obtained prove that the developed model is reliable and efficient.
The paper presents the study of corrosion phenomena for CoCrMo and CoCrMoSi5 alloys, in biologica... more The paper presents the study of corrosion phenomena for CoCrMo and CoCrMoSi5 alloys, in biological fluids, like citric acid (unpasteurized fresh orange juice). The study was made by electrochemical methods, using potentio-dynamic method and electrochemical impedance spectroscopy. It was found that CoCrMoSi5 alloy present high properties and may be used to medical applications.
The electrochemical behaviour of Zr5Ti, Zr25Ti, and Zr45Ti, with and without surface modification... more The electrochemical behaviour of Zr5Ti, Zr25Ti, and Zr45Ti, with and without surface modification were monitored in acidic artificial saliva (pH = 3) containing NaF concentrations 0.2, 0.5, and 1 wt.%, simulating the fluoride concentrations in dental rinses. A passive behaviour for thermally oxidized ZrTi alloys was found using EIS, and XPS data show that the protective oxide film contains both TiO2 and ZrO2, though titanium contents in the outer layer bigger than those in the base alloy result from thermal oxidation. High corrosion resistance to acidic fluoridated environments of ZrTi alloys treated using thermal oxidation in air at 500 ºC.
Abstract The aim of this study was to investigate the effects of immersion time on the electroche... more Abstract The aim of this study was to investigate the effects of immersion time on the electrochemical corrosion behaviour of three brass alloys (CuZn) coming from religious artefacts in simulated acid rain at 25° C, utilising the electrochemical impedance ...
Abstract The aim of this study was to investigate the effects of immersion time on the electroche... more Abstract The aim of this study was to investigate the effects of immersion time on the electrochemical corrosion behaviour of three brass alloys (CuZn) coming from religious artefacts in simulated acid rain at 25° C, utilising the electrochemical impedance ...
Journal of Materials Science: Materials in Medicine, 2010
To evaluate the potential of b-Ti20Mo alloy as a dental material, we tested its corrosion behavio... more To evaluate the potential of b-Ti20Mo alloy as a dental material, we tested its corrosion behaviour in artificial saliva in comparison to that of cp-Ti. Open-circuit potential (E OC ), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used as electrochemical methods to characterize the corrosion behaviour of Ti20Mo alloy and cp-Ti, respectively. Corrosion current and passive current densities obtained from the polarization curves showed low values indicating a typical passive behaviour for Ti20Mo alloy. The EIS technique enabled us to study the nature of the passive film formed on the binary Ti20Mo alloy at various imposed potentials. The Bode phase spectra obtained for Ti20Mo alloy in artificial saliva exhibited two-time constants at higher potential (0.5 V, 1.0 V), indicating a two-layer structure. According to our experimental measurements, Ti20Mo alloy appears to possess superior corrosion resistance to that of cp-Ti in artificial saliva.
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Pa... more ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Paliag (Ag-Pd based), Wiron 99 (Ni-Cr based), Cp-Ti (commercial pure titanium), and experimental Ti12Mo5Ta alloy in commercial mouthwash solution with 500 ppm F− (Oral B®) and compares it with the behavior of the same dental materials in artificial saliva. Linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) are the electrochemical procedures of investigation. The passivation of all dental samples in artificial saliva and mouthwash solution occurred spontaneously at open circuit potential. The corrosion current density of all tested dental materials in mouthwash solution were low (1-2 μA/cm2). The results suggest a non-predominant fluoride effect on the passive layer formed on all samples at open circuit potential. No passivation could be established with Paliag alloy when polarized in mouthwash solution. The EIS results confirm that all dental sample exhibit passivity in mouthwash solution at open circuit potential (polarization resistance was around 5 × 105 Ω cm2). For Paliag alloy after LPP in mouthwash solution the protectiveness passive layer was no more present. The corrosion resistances of four dental materials in mouthwash solution are in the following order: Ti12Mo5Ta > Cp-Ti > Wiron 99 > Paliag.
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Pa... more ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Paliag (Ag-Pd based), Wiron 99 (Ni-Cr based), Cp-Ti (commercial pure titanium), and experimental Ti12Mo5Ta alloy in commercial mouthwash solution with 500 ppm F− (Oral B®) and compares it with the behavior of the same dental materials in artificial saliva. Linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) are the electrochemical procedures of investigation. The passivation of all dental samples in artificial saliva and mouthwash solution occurred spontaneously at open circuit potential. The corrosion current density of all tested dental materials in mouthwash solution were low (1-2 μA/cm2). The results suggest a non-predominant fluoride effect on the passive layer formed on all samples at open circuit potential. No passivation could be established with Paliag alloy when polarized in mouthwash solution. The EIS results confirm that all dental sample exhibit passivity in mouthwash solution at open circuit potential (polarization resistance was around 5 × 105 Ω cm2). For Paliag alloy after LPP in mouthwash solution the protectiveness passive layer was no more present. The corrosion resistances of four dental materials in mouthwash solution are in the following order: Ti12Mo5Ta > Cp-Ti > Wiron 99 > Paliag.
Journal of Materials Engineering and Performance, 2012
The aim of this study is to investigate the electrochemical behavior of the five non-precious Ni-... more The aim of this study is to investigate the electrochemical behavior of the five non-precious Ni-based dental casting alloys in acidified artificial saliva. For comparison, nickel was also investigated. In order to study the localized corrosion resistance, the cyclic potentiodynamic polarization (CCP) and electrochemical impedance spectroscopy were performed. Scanning electron microscopy (SEM) observations were made after the CCP tests. The
The inhibitory activity of caffeine (1,3,7-trimethyl xanthine) on artificial saliva was studied o... more The inhibitory activity of caffeine (1,3,7-trimethyl xanthine) on artificial saliva was studied on a CoCrMo alloy using different electrochemical methods: open circuit potential (OCP), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The results show that caffeine produces an inhibitory effect on the anodic currents due to its adsorption on the surface of the alloy. Temperature is another parameter with an influence on corrosion processes, so thermodynamic data were obtained from Arrhenius plots and Langmuir adsorption isotherms. The protective action of caffeine is enhanced at high temperatures at OCP, while for potentiodynamic experiments high temperatures block the inhibitory activity of caffeine and the corrosion rate increases. The process may also be studied by a simulation, determining the functional dependence between OCP, corrosion current density (icorr), corrosion potential (Ecorr), breakdown potential (E bd ) and temperature and amount of caffeine in artificial saliva, for Heraenium CE. The neural network-based methodology applied in this work provides accurate results, thus proving to be an efficient modelling technique.
Besides other important material features, the corrosion parameters and corrosion products are re... more Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biocompatibility of metallic materials, and can produce undesirable reactions in implant-adjacent and/or more distant tissues. Titanium and some of its alloys are known as being the most biocompatible metallic materials due to their high strength, low modulus, high corrosion resistance in biological media, etc. More recently, Ti-Ta alloys have been developed, and these are expected to become more promising candidates for biomedical and dental applications than commercially pure Ti, Ti-6Al-4V or Ti-6Al-7Nb alloy. The corrosion behavior of the studied Ti-Ta alloys with Ta contents of 30, 40, 50 and 60 wt.% together with the currently used Ti-6Al-7Nb alloy were investigated for dental applications. All alloys were tested by open-circuit potential measurement, linear polarization, potentiodynamic polarization, coulometric zone analysis and electrochemical impedance spectroscopy performed in artificial saliva with different pH, acid lactic and fluoride contents. The passive behavior for all the titanium alloys is observed for artificial saliva, acidified saliva (9.8 g l À1 lactic acid, pH 2.5) and for fluoridated saliva (1.0 g l À1 F À , pH 8). A decrease in corrosion resistance and less protective passive oxide films are observed for all titanium alloys in fluoridated acidified saliva (9.8 g l À1 lactic acid, 1.0 g l À1 F À , pH 2.5) in regard to other electrochemical media used within this work. It is worthy of note that the most important decrease was found for Ti-6Al-7Nb alloy. These conclusions are confirmed by all the electrochemical tests undertaken. However, the results confirm that the corrosion resistance of the studied Ti-Ta alloys in all saliva is better or similar to that of Ti-6Al-7Nb alloy, suggesting that the Ti-Ta alloys have potential for dental applications.
Transactions of Nonferrous Metals Society of China, 2013
Corrosion behaviour of the studied Ti12Mo and Ti60Ta alloys with the same Mo equivalent values (1... more Corrosion behaviour of the studied Ti12Mo and Ti60Ta alloys with the same Mo equivalent values (12%, mass fraction) together with the currently used metallic biomaterials Cp-Ti were investigated for dental applications. The electrochemical properties of the samples were examined using electrochemical techniques: such as open-circuit potential, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS), in two electrochemical media of artificial saliva and fluoridated artificial saliva (0.1% fluoride ions, F ) at 37 °C. Fluoride is commonly included in toothpastes, odontological gels and dental rinses to prevent dental caries and relieve dental sensitivity. The passive behaviour for all the titanium samples is observed for both solutions. The Ti60Ta alloy appears to possess superior corrosion resistance than the Ti12Mo and Cp-Ti in both electrochemical media.
The aim of this study is to investigate the electrochemical behavior of some dental metallic mate... more The aim of this study is to investigate the electrochemical behavior of some dental metallic materials in artificial saliva for different pH (5.6 and 3.4), NaF content (500 ppm, 1000 ppm, and 2000 ppm), and with albumin protein addition (0.6 wt.%) for pH 3.4. The corrosion resistance of the alloys was quantitatively evaluated by polarization resistance, estimated by electrochemical impedance spectroscopy method. An adaptive k-nearest-neighbor regression method was applied for evaluating the corrosion resistance of the alloys by simulation, depending on the operation conditions. The predictions provided by the model are useful for experimental practice, as they can replace or, at least, help to plan the experiments. The accurate results obtained prove that the developed model is reliable and efficient.
The paper presents the study of corrosion phenomena for CoCrMo and CoCrMoSi5 alloys, in biologica... more The paper presents the study of corrosion phenomena for CoCrMo and CoCrMoSi5 alloys, in biological fluids, like citric acid (unpasteurized fresh orange juice). The study was made by electrochemical methods, using potentio-dynamic method and electrochemical impedance spectroscopy. It was found that CoCrMoSi5 alloy present high properties and may be used to medical applications.
The electrochemical behaviour of Zr5Ti, Zr25Ti, and Zr45Ti, with and without surface modification... more The electrochemical behaviour of Zr5Ti, Zr25Ti, and Zr45Ti, with and without surface modification were monitored in acidic artificial saliva (pH = 3) containing NaF concentrations 0.2, 0.5, and 1 wt.%, simulating the fluoride concentrations in dental rinses. A passive behaviour for thermally oxidized ZrTi alloys was found using EIS, and XPS data show that the protective oxide film contains both TiO2 and ZrO2, though titanium contents in the outer layer bigger than those in the base alloy result from thermal oxidation. High corrosion resistance to acidic fluoridated environments of ZrTi alloys treated using thermal oxidation in air at 500 ºC.
Abstract The aim of this study was to investigate the effects of immersion time on the electroche... more Abstract The aim of this study was to investigate the effects of immersion time on the electrochemical corrosion behaviour of three brass alloys (CuZn) coming from religious artefacts in simulated acid rain at 25° C, utilising the electrochemical impedance ...
Abstract The aim of this study was to investigate the effects of immersion time on the electroche... more Abstract The aim of this study was to investigate the effects of immersion time on the electrochemical corrosion behaviour of three brass alloys (CuZn) coming from religious artefacts in simulated acid rain at 25° C, utilising the electrochemical impedance ...
Journal of Materials Science: Materials in Medicine, 2010
To evaluate the potential of b-Ti20Mo alloy as a dental material, we tested its corrosion behavio... more To evaluate the potential of b-Ti20Mo alloy as a dental material, we tested its corrosion behaviour in artificial saliva in comparison to that of cp-Ti. Open-circuit potential (E OC ), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used as electrochemical methods to characterize the corrosion behaviour of Ti20Mo alloy and cp-Ti, respectively. Corrosion current and passive current densities obtained from the polarization curves showed low values indicating a typical passive behaviour for Ti20Mo alloy. The EIS technique enabled us to study the nature of the passive film formed on the binary Ti20Mo alloy at various imposed potentials. The Bode phase spectra obtained for Ti20Mo alloy in artificial saliva exhibited two-time constants at higher potential (0.5 V, 1.0 V), indicating a two-layer structure. According to our experimental measurements, Ti20Mo alloy appears to possess superior corrosion resistance to that of cp-Ti in artificial saliva.
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Pa... more ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Paliag (Ag-Pd based), Wiron 99 (Ni-Cr based), Cp-Ti (commercial pure titanium), and experimental Ti12Mo5Ta alloy in commercial mouthwash solution with 500 ppm F− (Oral B®) and compares it with the behavior of the same dental materials in artificial saliva. Linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) are the electrochemical procedures of investigation. The passivation of all dental samples in artificial saliva and mouthwash solution occurred spontaneously at open circuit potential. The corrosion current density of all tested dental materials in mouthwash solution were low (1-2 μA/cm2). The results suggest a non-predominant fluoride effect on the passive layer formed on all samples at open circuit potential. No passivation could be established with Paliag alloy when polarized in mouthwash solution. The EIS results confirm that all dental sample exhibit passivity in mouthwash solution at open circuit potential (polarization resistance was around 5 × 105 Ω cm2). For Paliag alloy after LPP in mouthwash solution the protectiveness passive layer was no more present. The corrosion resistances of four dental materials in mouthwash solution are in the following order: Ti12Mo5Ta > Cp-Ti > Wiron 99 > Paliag.
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Pa... more ABSTRACT This study investigates the electrochemical behavior of the various dental materials: Paliag (Ag-Pd based), Wiron 99 (Ni-Cr based), Cp-Ti (commercial pure titanium), and experimental Ti12Mo5Ta alloy in commercial mouthwash solution with 500 ppm F− (Oral B®) and compares it with the behavior of the same dental materials in artificial saliva. Linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) are the electrochemical procedures of investigation. The passivation of all dental samples in artificial saliva and mouthwash solution occurred spontaneously at open circuit potential. The corrosion current density of all tested dental materials in mouthwash solution were low (1-2 μA/cm2). The results suggest a non-predominant fluoride effect on the passive layer formed on all samples at open circuit potential. No passivation could be established with Paliag alloy when polarized in mouthwash solution. The EIS results confirm that all dental sample exhibit passivity in mouthwash solution at open circuit potential (polarization resistance was around 5 × 105 Ω cm2). For Paliag alloy after LPP in mouthwash solution the protectiveness passive layer was no more present. The corrosion resistances of four dental materials in mouthwash solution are in the following order: Ti12Mo5Ta > Cp-Ti > Wiron 99 > Paliag.
Journal of Materials Engineering and Performance, 2012
The aim of this study is to investigate the electrochemical behavior of the five non-precious Ni-... more The aim of this study is to investigate the electrochemical behavior of the five non-precious Ni-based dental casting alloys in acidified artificial saliva. For comparison, nickel was also investigated. In order to study the localized corrosion resistance, the cyclic potentiodynamic polarization (CCP) and electrochemical impedance spectroscopy were performed. Scanning electron microscopy (SEM) observations were made after the CCP tests. The
The inhibitory activity of caffeine (1,3,7-trimethyl xanthine) on artificial saliva was studied o... more The inhibitory activity of caffeine (1,3,7-trimethyl xanthine) on artificial saliva was studied on a CoCrMo alloy using different electrochemical methods: open circuit potential (OCP), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The results show that caffeine produces an inhibitory effect on the anodic currents due to its adsorption on the surface of the alloy. Temperature is another parameter with an influence on corrosion processes, so thermodynamic data were obtained from Arrhenius plots and Langmuir adsorption isotherms. The protective action of caffeine is enhanced at high temperatures at OCP, while for potentiodynamic experiments high temperatures block the inhibitory activity of caffeine and the corrosion rate increases. The process may also be studied by a simulation, determining the functional dependence between OCP, corrosion current density (icorr), corrosion potential (Ecorr), breakdown potential (E bd ) and temperature and amount of caffeine in artificial saliva, for Heraenium CE. The neural network-based methodology applied in this work provides accurate results, thus proving to be an efficient modelling technique.
Besides other important material features, the corrosion parameters and corrosion products are re... more Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biocompatibility of metallic materials, and can produce undesirable reactions in implant-adjacent and/or more distant tissues. Titanium and some of its alloys are known as being the most biocompatible metallic materials due to their high strength, low modulus, high corrosion resistance in biological media, etc. More recently, Ti-Ta alloys have been developed, and these are expected to become more promising candidates for biomedical and dental applications than commercially pure Ti, Ti-6Al-4V or Ti-6Al-7Nb alloy. The corrosion behavior of the studied Ti-Ta alloys with Ta contents of 30, 40, 50 and 60 wt.% together with the currently used Ti-6Al-7Nb alloy were investigated for dental applications. All alloys were tested by open-circuit potential measurement, linear polarization, potentiodynamic polarization, coulometric zone analysis and electrochemical impedance spectroscopy performed in artificial saliva with different pH, acid lactic and fluoride contents. The passive behavior for all the titanium alloys is observed for artificial saliva, acidified saliva (9.8 g l À1 lactic acid, pH 2.5) and for fluoridated saliva (1.0 g l À1 F À , pH 8). A decrease in corrosion resistance and less protective passive oxide films are observed for all titanium alloys in fluoridated acidified saliva (9.8 g l À1 lactic acid, 1.0 g l À1 F À , pH 2.5) in regard to other electrochemical media used within this work. It is worthy of note that the most important decrease was found for Ti-6Al-7Nb alloy. These conclusions are confirmed by all the electrochemical tests undertaken. However, the results confirm that the corrosion resistance of the studied Ti-Ta alloys in all saliva is better or similar to that of Ti-6Al-7Nb alloy, suggesting that the Ti-Ta alloys have potential for dental applications.
Transactions of Nonferrous Metals Society of China, 2013
Corrosion behaviour of the studied Ti12Mo and Ti60Ta alloys with the same Mo equivalent values (1... more Corrosion behaviour of the studied Ti12Mo and Ti60Ta alloys with the same Mo equivalent values (12%, mass fraction) together with the currently used metallic biomaterials Cp-Ti were investigated for dental applications. The electrochemical properties of the samples were examined using electrochemical techniques: such as open-circuit potential, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS), in two electrochemical media of artificial saliva and fluoridated artificial saliva (0.1% fluoride ions, F ) at 37 °C. Fluoride is commonly included in toothpastes, odontological gels and dental rinses to prevent dental caries and relieve dental sensitivity. The passive behaviour for all the titanium samples is observed for both solutions. The Ti60Ta alloy appears to possess superior corrosion resistance than the Ti12Mo and Cp-Ti in both electrochemical media.
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