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Hyung-min Shim - One of the best experts on this subject based on the ideXlab platform.

  • Surface characteristics of titanium–Silver Alloys in artificial saliva
    Surface and Interface Analysis, 2020
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Titanium and its Alloys are widely used in biomedical and dental fields because of their excellent corrosion resistance and biocompatibility. It is well known that titanium is protected from corrosion because of the stability of the passive film that controls and determines the corrosion resistance and biocompatibility of titanium and its Alloys. The purpose of this study was to evaluate the electrochemical properties of titanium–Silver Alloys and the surface characteristics of passive film in artificial saliva. We designed titanium–Silver Alloys with Silver contents ranging from 0 to 5 at.%, in 1% increments. These Alloys were arc-melted, homogenized, hot-rolled to 2 mm thickness, and finally solution heat-treated for 1 h and quenched. Potentiostatic testing was performed, and the open circuit potentials of the Alloys were measured in artificial saliva, at 37 °C. The passive films of the titanium–Silver Alloys were analyzed via XPS. Titanium–Silver Alloys maintained low current density and showed stable passive region and also had high open circuit potential as compared with pure titanium. The open circuit potential of titanium–Silver Alloys increased as Silver addition increased. With regard to the fraction of oxygen species, a component of over 80% was found to be comprised of oxide. Therefore, the titanium surface mainly consisted of titanium oxide and, on the titanium–Silver Alloys, this film was composed of TiO2, Ti2O3, and TiO. As Silver content increased, the TiO2 fraction also increased, as did the thickness of the titanium oxide layer formed. Copyright © 2005 John Wiley & Sons, Ltd.

  • Properties of titanium–Silver Alloys for dental application
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium–Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–Silver Alloys in artificial saliva. Titanium–Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium–Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium–Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium–Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium–Silver Alloys and of titanium were none or mild. In summary, titanium–Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–Silver Alloys be adopted cautiously by the biomedical and dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • properties of titanium Silver Alloys for dental application
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium–Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–Silver Alloys in artificial saliva. Titanium–Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium–Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium–Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium–Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium–Silver Alloys and of titanium were none or mild. In summary, titanium–Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–Silver Alloys be adopted cautiously by the biomedical and dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • Corrosion resistance of titanium-Silver Alloys in an artificial saliva containing fluoride ions.
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Dental gels and rinses for caries prophylactic contain fluoride at concentrations ranging from 0.1 to 1%. In addition, many types of fluoride-releasing materials have been used in dental applications. The purpose of the study was to investigate the addition effect of fluoride into artificial saliva on the corrosion resistance of pure titanium and titanium–Silver Alloys. Titanium and titanium–Silver Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled, and solution heat treated and quenched. In order to investigate the effect of the fluoride ions on the corrosion resistance, potentiodynamic polarization testing, potentiostatic testing, and open-circuit potential measurements were performed in plain artificial saliva and 0.1 and 1% NaF-added artificial saliva. The passive current densities of titanium and titanium–Silver Alloys increased with increasing fluoride-ion concentration. Ti2.0Ag and Ti3.0Ag exhibited a low current density relatively and showed a stable behavior compared to titanium. The open-circuit potential of titanium decreased and current density at 250 mV (SCE) potentiostatic testing reacted sensitively with increasing fluoride concentration. On the other hand, the open-circuit potential of titanium–Silver Alloys with a high Silver content (3.0–4.0 at %) reacted less sensitively to the fluoride-ion concentration. Among titanium–Silver Alloys, Ti3.0Ag alloy had a higher resistance against the attack of fluoride ions and showed a more stable open-circuit potential and current density than titanium in the fluoride-containing solution. It is concluded that they are electrochemically stable and maintained good corrosion resistance in fluoride-containing artificial saliva. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • properties of titanium Silver Alloys for dental application
    Journal of Biomedical Materials Research, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium-Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium-Silver Alloys in artificial saliva. Titanium-Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium-Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0-4.0 at %, the formation of an acicular a phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium-Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α-β phase transition. Moreover, titanium-Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium-Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium-Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium-Silver Alloys and of titanium were none or mild. In summary, titanium-Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium-Silver Alloys be adopted cautiously by the biomedical and dental fields.

Keun-taek Oh - One of the best experts on this subject based on the ideXlab platform.

  • Surface characteristics of titanium–Silver Alloys in artificial saliva
    Surface and Interface Analysis, 2020
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Titanium and its Alloys are widely used in biomedical and dental fields because of their excellent corrosion resistance and biocompatibility. It is well known that titanium is protected from corrosion because of the stability of the passive film that controls and determines the corrosion resistance and biocompatibility of titanium and its Alloys. The purpose of this study was to evaluate the electrochemical properties of titanium–Silver Alloys and the surface characteristics of passive film in artificial saliva. We designed titanium–Silver Alloys with Silver contents ranging from 0 to 5 at.%, in 1% increments. These Alloys were arc-melted, homogenized, hot-rolled to 2 mm thickness, and finally solution heat-treated for 1 h and quenched. Potentiostatic testing was performed, and the open circuit potentials of the Alloys were measured in artificial saliva, at 37 °C. The passive films of the titanium–Silver Alloys were analyzed via XPS. Titanium–Silver Alloys maintained low current density and showed stable passive region and also had high open circuit potential as compared with pure titanium. The open circuit potential of titanium–Silver Alloys increased as Silver addition increased. With regard to the fraction of oxygen species, a component of over 80% was found to be comprised of oxide. Therefore, the titanium surface mainly consisted of titanium oxide and, on the titanium–Silver Alloys, this film was composed of TiO2, Ti2O3, and TiO. As Silver content increased, the TiO2 fraction also increased, as did the thickness of the titanium oxide layer formed. Copyright © 2005 John Wiley & Sons, Ltd.

  • Properties of titanium–Silver Alloys for dental application
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium–Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–Silver Alloys in artificial saliva. Titanium–Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium–Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium–Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium–Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium–Silver Alloys and of titanium were none or mild. In summary, titanium–Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–Silver Alloys be adopted cautiously by the biomedical and dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • properties of titanium Silver Alloys for dental application
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium–Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium–Silver Alloys in artificial saliva. Titanium–Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium–Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium–Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium–Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium–Silver Alloys and of titanium were none or mild. In summary, titanium–Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–Silver Alloys be adopted cautiously by the biomedical and dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • Corrosion resistance of titanium-Silver Alloys in an artificial saliva containing fluoride ions.
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Dental gels and rinses for caries prophylactic contain fluoride at concentrations ranging from 0.1 to 1%. In addition, many types of fluoride-releasing materials have been used in dental applications. The purpose of the study was to investigate the addition effect of fluoride into artificial saliva on the corrosion resistance of pure titanium and titanium–Silver Alloys. Titanium and titanium–Silver Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled, and solution heat treated and quenched. In order to investigate the effect of the fluoride ions on the corrosion resistance, potentiodynamic polarization testing, potentiostatic testing, and open-circuit potential measurements were performed in plain artificial saliva and 0.1 and 1% NaF-added artificial saliva. The passive current densities of titanium and titanium–Silver Alloys increased with increasing fluoride-ion concentration. Ti2.0Ag and Ti3.0Ag exhibited a low current density relatively and showed a stable behavior compared to titanium. The open-circuit potential of titanium decreased and current density at 250 mV (SCE) potentiostatic testing reacted sensitively with increasing fluoride concentration. On the other hand, the open-circuit potential of titanium–Silver Alloys with a high Silver content (3.0–4.0 at %) reacted less sensitively to the fluoride-ion concentration. Among titanium–Silver Alloys, Ti3.0Ag alloy had a higher resistance against the attack of fluoride ions and showed a more stable open-circuit potential and current density than titanium in the fluoride-containing solution. It is concluded that they are electrochemically stable and maintained good corrosion resistance in fluoride-containing artificial saliva. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • properties of titanium Silver Alloys for dental application
    Journal of Biomedical Materials Research, 2005
    Co-Authors: Keun-taek Oh, Hyung-min Shim
    Abstract:

    The purpose of this study was to develop titanium-Silver Alloys with biocompatibility, high corrosion resistance, and low ion-release rate, and to evaluate the electrochemical properties of titanium-Silver Alloys in artificial saliva. Titanium-Silver Alloys with Silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the Alloys were investigated. The purity of titanium-Silver Alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of Alloys containing Silver in the range 2.0-4.0 at %, the formation of an acicular a phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of Silver. This means that Silver is a β-phase stabilizing element in titanium-Silver Alloys. The hardness value tended to rise with increasing Silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α-β phase transition. Moreover, titanium-Silver Alloys had higher corrosion resistances than pure titanium. These results mean that Silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium-Silver Alloys. However, they did not show a linear relationship with respect to Silver contents. Titanium-Silver Alloys did not show pitting corrosion in artificial saliva. It is believed that Silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and Silver. In the agar overlay test, the cytotoxicity of the titanium-Silver Alloys and of titanium were none or mild. In summary, titanium-Silver Alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium-Silver Alloys be adopted cautiously by the biomedical and dental fields.

Emília Illeková - One of the best experts on this subject based on the ideXlab platform.

  • Thermophysical Properties of Liquid Silver-Bismuth-Tin Alloys
    Journal of Materials Engineering and Performance, 2012
    Co-Authors: Yu Plevachuk, D. Janickovic, A. Yakymovych, V Sklyarchuk, Petr Svec, Emília Illeková
    Abstract:

    Tin-bismuth-Silver Alloys are under intense consideration as favorable lead-free solders for consumer electronics and telecommunications. The investigated samples of Ag-Bi10-Sn with Ag content from 3.33 to 10 at.% were prepared both in the traditional bulk form and in the ribbon form by the rapid solidification technique. The electrical conductivity and thermal conductivity, thermoelectric power and viscosity studies were carried out in a wide temperature range above the liquidus. Corresponding fit relations have been derived.

Chung-ju Hwang - One of the best experts on this subject based on the ideXlab platform.

  • Surface characteristics of titanium–Silver Alloys in artificial saliva
    Surface and Interface Analysis, 2020
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Titanium and its Alloys are widely used in biomedical and dental fields because of their excellent corrosion resistance and biocompatibility. It is well known that titanium is protected from corrosion because of the stability of the passive film that controls and determines the corrosion resistance and biocompatibility of titanium and its Alloys. The purpose of this study was to evaluate the electrochemical properties of titanium–Silver Alloys and the surface characteristics of passive film in artificial saliva. We designed titanium–Silver Alloys with Silver contents ranging from 0 to 5 at.%, in 1% increments. These Alloys were arc-melted, homogenized, hot-rolled to 2 mm thickness, and finally solution heat-treated for 1 h and quenched. Potentiostatic testing was performed, and the open circuit potentials of the Alloys were measured in artificial saliva, at 37 °C. The passive films of the titanium–Silver Alloys were analyzed via XPS. Titanium–Silver Alloys maintained low current density and showed stable passive region and also had high open circuit potential as compared with pure titanium. The open circuit potential of titanium–Silver Alloys increased as Silver addition increased. With regard to the fraction of oxygen species, a component of over 80% was found to be comprised of oxide. Therefore, the titanium surface mainly consisted of titanium oxide and, on the titanium–Silver Alloys, this film was composed of TiO2, Ti2O3, and TiO. As Silver content increased, the TiO2 fraction also increased, as did the thickness of the titanium oxide layer formed. Copyright © 2005 John Wiley & Sons, Ltd.

  • Corrosion resistance of titanium-Silver Alloys in an artificial saliva containing fluoride ions.
    Journal of Biomedical Materials Research Part B, 2005
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Dental gels and rinses for caries prophylactic contain fluoride at concentrations ranging from 0.1 to 1%. In addition, many types of fluoride-releasing materials have been used in dental applications. The purpose of the study was to investigate the addition effect of fluoride into artificial saliva on the corrosion resistance of pure titanium and titanium–Silver Alloys. Titanium and titanium–Silver Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled, and solution heat treated and quenched. In order to investigate the effect of the fluoride ions on the corrosion resistance, potentiodynamic polarization testing, potentiostatic testing, and open-circuit potential measurements were performed in plain artificial saliva and 0.1 and 1% NaF-added artificial saliva. The passive current densities of titanium and titanium–Silver Alloys increased with increasing fluoride-ion concentration. Ti2.0Ag and Ti3.0Ag exhibited a low current density relatively and showed a stable behavior compared to titanium. The open-circuit potential of titanium decreased and current density at 250 mV (SCE) potentiostatic testing reacted sensitively with increasing fluoride concentration. On the other hand, the open-circuit potential of titanium–Silver Alloys with a high Silver content (3.0–4.0 at %) reacted less sensitively to the fluoride-ion concentration. Among titanium–Silver Alloys, Ti3.0Ag alloy had a higher resistance against the attack of fluoride ions and showed a more stable open-circuit potential and current density than titanium in the fluoride-containing solution. It is concluded that they are electrochemically stable and maintained good corrosion resistance in fluoride-containing artificial saliva. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater

  • corrosion resistance of titanium Silver Alloys in an artificial saliva containing fluoride ions
    Journal of Biomedical Materials Research, 2005
    Co-Authors: Hyung-min Shim, Keun-taek Oh, Chung-ju Hwang
    Abstract:

    Dental gels and rinses for caries prophylactic contain fluoride at concentrations ranging from 0.1 to 1%. In addition, many types of fluoride-releasing materials have been used in dental applications. The purpose of the study was to investigate the addition effect of fluoride into artificial saliva on the corrosion resistance of pure titanium and titanium-Silver Alloys. Titanium and titanium-Silver Alloys were arc melted, homogenized at 950°C for 72 h, hot rolled, and solution heat treated and quenched. In order to investigate the effect of the fluoride ions on the corrosion resistance, potentiodynamic polarization testing, potentiostatic testing, and open-circuit potential measurements were performed in plain artificial saliva and 0.1 and 1% NaF-added artificial saliva. The passive current densities of titanium and titanium-Silver Alloys increased with increasing fluoride-ion concentration. Ti2.0Ag and Ti3.0Ag exhibited a low current density relatively and showed a stable behavior compared to titanium. The open-circuit potential of titanium decreased and current density at 250 mV (SCE) potentiostatic testing reacted sensitively with increasing fluoride concentration. On the other hand, the open-circuit potential of titanium-Silver Alloys with a high Silver content (3.0-4.0 at %) reacted less sensitively to the fluoride-ion concentration. Among titanium-Silver Alloys, Ti3.0Ag alloy had a higher resistance against the attack of fluoride ions and showed a more stable open-circuit potential and current density than titanium in the fluoride-containing solution. It is concluded that they are electrochemically stable and maintained good corrosion resistance in fluoride-containing artificial saliva.

Andre Lefort - One of the best experts on this subject based on the ideXlab platform.

  • Work function measurements of contact materials for industrial use
    Journal of Applied Physics, 1998
    Co-Authors: Mohammed Akbi, Andre Lefort
    Abstract:

    The nature of the contact material is important for the characteristics of electric arcs and particularly for the electronic emission. Work functions of new industrial materials made with Silver Alloys and Silver oxide Alloys are not known at present. An experimental set-up is described which allows work function measurements from room temperature up to 700 K. The Fowler method was used for the measurement of the work function by the photoelectric effect. As a first application of the experimental device, work functions of metals (Ag, Cu, Ni, Sn and Zn) were determined. Furthermore, the influence of industrial surface treatment such as the application of electric arcs and repeated mechanical shocks on the Ag contact work surface was studied by SEM to observe their effect on electron work function. Breaking arcs in air cause a remarkable increase in the work function of the Silver contact material by progressive formation of Silver oxides.

  • Experimental determination of work function of Silver Alloys
    XVI International Symposium on Discharges and Electrical Insulation in Vacuum, 1994
    Co-Authors: Andre Lefort, Mohamed Akbi, Marie-jose Parizet
    Abstract:

    Models about arc roots need a good knowledge of physical constants characterizing contact material. With pure metal, all the constants are well known; but for Alloys some are not known. In this paper we relate how we have measured work function of Silver Alloys.