The Experts below are selected from a list of 30153 Experts worldwide ranked by ideXlab platform

Paul F Herman - One of the best experts on this subject based on the ideXlab platform.

  • cobalt chromium and nickel chromium Alloys for removable prosthodontics part 1 mechanical properties
    Journal of Prosthodontics, 1993
    Co-Authors: David A Bridgeport, William A Brantley, Paul F Herman
    Abstract:

    Purpose This investigation compared the mechanical properties of three base metal casting Alloys (Vitallium2, Neoloy N [Regular], and Regalloy T) for removable partial denture (RPD) frameworks with those for two base metal RPD Alloys (Vitallium, Jelenko LG) whose mechanical properties had been previously reported. Materials and Methods Plastic patterns with dimensions meeting ADA specification no. 14 requirements were used with appropriate casting investments to cast tensile test bars of the five Alloys. Nine specimens of each alloy were loaded to failure, and the mechanical properties of modulus of elasticity, 0.1% yield strength, 0.2% yield strength, and tensile strength were obtained from five well-behaved load-elongation plots. Values of percentage elongation were also determined, along with Vickers hardness of the work-hardened Alloys from polished cross-sections of fractured tensile specimens. The fracture surfaces for representative specimens of each alloy were examined with a scanning electron microscope. Results Although the measured values of mechanical properties generally agreed with those reported by the manufacturers, differences found for Vitallium and Jelenko LG with previous investigations suggest that there may have been some changes in alloy compositions and processing by the manufacturers. The investment burnout procedure adopted for the plastic patterns and the present casting conditions may also have affected the mechanical properties of some Alloys. Two Alloys, Jelenko LG and Regalloy T, had mean values of percentage elongation exceeding 10%, but caution is recommended for clinicians and dental laboratories when performing clasp adjustments with all five Alloys because of the substantial work hardening that can occur. Conclusions In general, all of the Alloys met the requirements in ADA specification no. 14 for base metal RPD Alloys. Further research will be necessary to determine the relationships between the mechanical properties, particularly yield strength, rate of work hardening and percentage elongation, and the clinical requirements for these Alloys.

David E. Alman - One of the best experts on this subject based on the ideXlab platform.

  • Effect of manganese addition on reactive evaporation of chromium in Ni-Cr Alloys
    Journal of Materials Engineering and Performance, 2006
    Co-Authors: Gordon R. Holcomb, David E. Alman
    Abstract:

    Chromium is used as an alloy addition in stainless steels and Nickel-Chromium Alloys to form protective chromium oxide scales. Chromium oxide undergoes reactive evaporation in high-temperature exposures in the presence of oxygen and/or water vapor. Deposition of gaseous chromium species onto solid oxide fuel-cell electrodes can reduce the efficiency of the fuel cell. Manganese additions to the alloy can reduce the activity of chromium in the oxide, either from solid solution replacement of chromium with manganese (at low levels of manganese) or from the formation of manganese-chromium spinels (at high levels of manganese). This reduction in chromium activity leads to a predicted reduction in chromium evaporation factors as much as 35 at 800 °C and 55 at 700 °C. Quantifying the effects of manganese additions on chromium evaporation should aid alloy development of metallic interconnects and balance-of-plant Alloys.

  • the effect of manganese additions on the reactive evaporation of chromium in ni cr Alloys
    ASM Materials Solutions Conference and Exposition Columbus OH Oct. 18-21 2004 (sponsored by ASM International Materials Park OH); Related Information:, 2004
    Co-Authors: Gordon R. Holcomb, David E. Alman
    Abstract:

    Chromium is used as an alloy addition in stainless steels and Nickel-Chromium Alloys to form protective chromium oxide scales. Chromium oxide undergoes reactive evaporation in high temperature exposures in the presence of oxygen and/or water vapor. The deposition of gaseous chromium species onto solid oxide fuel cell electrodes can reduce the efficiency of the fuel cell. Manganese additions to the alloy can reduce the activity of chromium in the oxide, either from solid solution replacement of chromium with manganese (at low levels of manganese) or from the formation of manganese-chromium spinels (at high levels of manganese). This reduction in chromium activity leads to a predicted reduction in chromium evaporation by as much as a factor of 35 at 800 C and 55 at 700 C. The results of evaporation loss measurements on Nickel-Chromium-manganese Alloys are compared with the predicted reduction. Quantifying the effects of manganese additions on chromium evaporation should aid alloy development of metallic interconnects and balance-of-plant Alloys.

David A Bridgeport - One of the best experts on this subject based on the ideXlab platform.

  • cobalt chromium and nickel chromium Alloys for removable prosthodontics part 1 mechanical properties
    Journal of Prosthodontics, 1993
    Co-Authors: David A Bridgeport, William A Brantley, Paul F Herman
    Abstract:

    Purpose This investigation compared the mechanical properties of three base metal casting Alloys (Vitallium2, Neoloy N [Regular], and Regalloy T) for removable partial denture (RPD) frameworks with those for two base metal RPD Alloys (Vitallium, Jelenko LG) whose mechanical properties had been previously reported. Materials and Methods Plastic patterns with dimensions meeting ADA specification no. 14 requirements were used with appropriate casting investments to cast tensile test bars of the five Alloys. Nine specimens of each alloy were loaded to failure, and the mechanical properties of modulus of elasticity, 0.1% yield strength, 0.2% yield strength, and tensile strength were obtained from five well-behaved load-elongation plots. Values of percentage elongation were also determined, along with Vickers hardness of the work-hardened Alloys from polished cross-sections of fractured tensile specimens. The fracture surfaces for representative specimens of each alloy were examined with a scanning electron microscope. Results Although the measured values of mechanical properties generally agreed with those reported by the manufacturers, differences found for Vitallium and Jelenko LG with previous investigations suggest that there may have been some changes in alloy compositions and processing by the manufacturers. The investment burnout procedure adopted for the plastic patterns and the present casting conditions may also have affected the mechanical properties of some Alloys. Two Alloys, Jelenko LG and Regalloy T, had mean values of percentage elongation exceeding 10%, but caution is recommended for clinicians and dental laboratories when performing clasp adjustments with all five Alloys because of the substantial work hardening that can occur. Conclusions In general, all of the Alloys met the requirements in ADA specification no. 14 for base metal RPD Alloys. Further research will be necessary to determine the relationships between the mechanical properties, particularly yield strength, rate of work hardening and percentage elongation, and the clinical requirements for these Alloys.

Steven N Rogak - One of the best experts on this subject based on the ideXlab platform.

  • corrosion of nickel chromium Alloys stainless steel and niobium at supercritical water oxidation conditions
    Corrosion Science, 2010
    Co-Authors: Edouard Asselin, Akram Alfantazi, Steven N Rogak
    Abstract:

    Abstract Results of immersion tests of UNS N06625 (alloy 625), UNS S31609 (alloy 316 L), Ni–20Cr alloy and Nb coupons exposed to oxygenated ammoniacal sulphate solution at supercritical water oxidation (SCWO) conditions are presented. The corrosion behavior of the alloy 316 L (UNS S31603) SCWO reactor tubing is also presented under the same conditions. Immersion coupons corroded at a rate not exceeding 40 mm yr −1 while the reactor tube itself corroded at a rate of between 160–1500 mm yr −1 , depending on which length of the reactor is considered to have corroded. Morphological and chemical analysis of the oxides present on the coupon samples suggest that iron oxides, which had initially precipitated on the corroding alloy 316 tube surface, were removed by heat flux-driven fluid mechanical action and transported through the reactor where they deposited on the coupons. Niobium was resistant to corrosion at the tested conditions.

Gordon R. Holcomb - One of the best experts on this subject based on the ideXlab platform.

  • Effect of manganese addition on reactive evaporation of chromium in Ni-Cr Alloys
    Journal of Materials Engineering and Performance, 2006
    Co-Authors: Gordon R. Holcomb, David E. Alman
    Abstract:

    Chromium is used as an alloy addition in stainless steels and Nickel-Chromium Alloys to form protective chromium oxide scales. Chromium oxide undergoes reactive evaporation in high-temperature exposures in the presence of oxygen and/or water vapor. Deposition of gaseous chromium species onto solid oxide fuel-cell electrodes can reduce the efficiency of the fuel cell. Manganese additions to the alloy can reduce the activity of chromium in the oxide, either from solid solution replacement of chromium with manganese (at low levels of manganese) or from the formation of manganese-chromium spinels (at high levels of manganese). This reduction in chromium activity leads to a predicted reduction in chromium evaporation factors as much as 35 at 800 °C and 55 at 700 °C. Quantifying the effects of manganese additions on chromium evaporation should aid alloy development of metallic interconnects and balance-of-plant Alloys.

  • the effect of manganese additions on the reactive evaporation of chromium in ni cr Alloys
    ASM Materials Solutions Conference and Exposition Columbus OH Oct. 18-21 2004 (sponsored by ASM International Materials Park OH); Related Information:, 2004
    Co-Authors: Gordon R. Holcomb, David E. Alman
    Abstract:

    Chromium is used as an alloy addition in stainless steels and Nickel-Chromium Alloys to form protective chromium oxide scales. Chromium oxide undergoes reactive evaporation in high temperature exposures in the presence of oxygen and/or water vapor. The deposition of gaseous chromium species onto solid oxide fuel cell electrodes can reduce the efficiency of the fuel cell. Manganese additions to the alloy can reduce the activity of chromium in the oxide, either from solid solution replacement of chromium with manganese (at low levels of manganese) or from the formation of manganese-chromium spinels (at high levels of manganese). This reduction in chromium activity leads to a predicted reduction in chromium evaporation by as much as a factor of 35 at 800 C and 55 at 700 C. The results of evaporation loss measurements on Nickel-Chromium-manganese Alloys are compared with the predicted reduction. Quantifying the effects of manganese additions on chromium evaporation should aid alloy development of metallic interconnects and balance-of-plant Alloys.