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Sun D, Frankel GS, Brantley WA, Heshmati RH, Johnston WM. Electrochemical impedance spectroscopy study of corrosion characteristics of palladium-silver dental alloys. J Biomed Mater Res B Appl Biomater 2021; 109:1777-1786. [PMID: 33817975 DOI: 10.1002/jbm.b.34837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 02/02/2021] [Accepted: 03/06/2021] [Indexed: 01/01/2023]
Abstract
Electrochemical impedance spectroscopy (EIS) has been used to obtain insight into corrosion processes for three Pd-Ag alloys, and compare their behavior with an Au-Pd alloy. Five specimens of each alloy received clinically-appropriate simulated porcelain-firing heat treatment. EIS testing was performed at ambient temperature, using 0.09% NaCl, 0.9% NaCl and Fusayama solutions. EIS data are presented as Bode plots. At the open-circuit potential (OCP), the data fit a modified Randles equivalent electrical circuit with a constant phase element (CPE), and the charge-transfer resistance (RCT ) and the two CPE parameters (CPE-T and CPE-P) were determined. The area-normalized capacitance of the double layer (Cdl ) was also calculated. The EIS data at two relevant elevated potentials in the passive range were also found to fit well a modified Randles equivalent circuit with different values for the charge transfer resistance and CPE parameters. At the OCP no significant effect on RCT was found for the alloys and electrolytes, and both alloy and electrolyte significantly affected CPE-P. In vitro corrosion was controlled by charge transfer and charge accumulation processes, and the behavior differed at the elevated potentials compared to the OCP. Significant effects were found for alloy, electrolyte, and alloy/electrolyte interaction on Cdl at the OCP. The EIS parameters at elevated potentials indicate that the Pd-Ag alloys should have satisfactory clinical corrosion resistance. The EIS analyses yielded information about in vitro corrosion of these alloys that cannot be obtained from potentiodynamic polarization testing.
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Affiliation(s)
- Desheng Sun
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Gerald S Frankel
- Department of Materials Science and Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - William A Brantley
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Reza H Heshmati
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - William M Johnston
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
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Detisch MJ, John Balk T, Bezold M, Bhattacharyya D. Nanoporous metal-polymer composite membranes for organics separations and catalysis. JOURNAL OF MATERIALS RESEARCH 2020; 35:2629-2642. [PMID: 37539433 PMCID: PMC10399685 DOI: 10.1557/jmr.2020.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Metallic thin-film composite membranes are produced by sputtering metal films onto commercial polymer membranes. The separations capability of the membrane substrate is enhanced with the addition of a 10 nm Ta film. The addition of a tantalum layer decreases the molecular weight cutoff of the membrane from 70 kDa dextran (19 nm) to below 5 kDa (6 nm). Water flux drops from 168 LMH/bar (LMH: liters/meters2/hour) (polymer support) to 8.8 LMH/bar (Ta composite). A nanoporous layer is also added to the surface through Mg/Pd film deposition and dealloying. The resulting nanoporous Pd is a promising catalyst with a ligament size of 4.1 ± 0.9 nm. The composite membrane's ability to treat water contaminated with chlorinated organic compounds (COCs) is determined. When pressurized with hydrogen gas, the nanoporous Pd composite removes over 70% of PCB-1, a model COC, with one pass. These nanostructured films can be incorporated onto membrane supports enabling diverse reactions and separations.
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Affiliation(s)
- Michael J. Detisch
- Department of Chemical & Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Thomas John Balk
- Department of Chemical & Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Mariah Bezold
- Department of Chemical & Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Dibakar Bhattacharyya
- Department of Chemical & Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
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Li X, Wang X, Roy K, van Bokhoven JA, Artiglia L. Role of Water on the Structure of Palladium for Complete Oxidation of Methane. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01069] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Xiansheng Li
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Xing Wang
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Kanak Roy
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Jeroen A. van Bokhoven
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Luca Artiglia
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232 Villigen, Switzerland
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An extensive investigation on gamma ray shielding features of Pd/Ag-based alloys. NUCLEAR ENGINEERING AND TECHNOLOGY 2019. [DOI: 10.1016/j.net.2018.12.014] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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A two-phase gradual silver release mechanism from a nanostructured TiAlV surface as a possible antibacterial modification in implants. Bioelectrochemistry 2019; 127:26-34. [PMID: 30654242 DOI: 10.1016/j.bioelechem.2019.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/06/2019] [Accepted: 01/07/2019] [Indexed: 01/27/2023]
Abstract
Titanium biomaterials are widely used in the medical field due to their biocompatibility and excellent corrosion and mechanical resistance. However, these materials have no antibacterial properties. To obtain an antibacterial active surface, a nanostructure of Ti6Al4V alloy was created. This specific nanostructure contained nanotubes and micro-cavities and was used as a substrate for silver anchoring. The electrochemical approach to silver reduction was studied. It is a common approach for silver deposition and in this work, inhomogeneities in the nanostructure were used as a preferential area for silver localisation. The galvanostatic regimen of deposition allowed for a technically quantitative process and the required silver placement. The experimental conditions used enabled testing and silver dissolution rate evaluation within a reasonable time span. Based on the corrosion and analytical results (EDS, XPS and ICP-MS), a two-phase silver release mechanism was confirmed. The openings of the individual nanotubes were filled with silver nanoparticles, whose release was relatively fast. By contrast, the silver anchored inside the cavities allowed the silver to release gradually. Antibacterial efficiency against Staphylococcus aureus and Escherichia coli was successfully demonstrated. Cytotoxicity testing with murine fibroblasts showed cell metabolic activity far above the normative limit of 70%.
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Sun D, Brantley WA, Frankel GS, Heshmati RH, Johnston WM. Potentiodynamic polarization study of the corrosion behavior of palladium-silver dental alloys. J Prosthet Dent 2018; 119:650-656. [DOI: 10.1016/j.prosdent.2017.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 10/18/2022]
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Muris J, Kleverlaan CJ, Rustemeyer T, von Blomberg ME, van Hoogstraten IMW, Feilzer AJ, Scheper RJ. Sodium tetrachloropalladate for diagnosing palladium sensitization. Contact Dermatitis 2012; 67:94-100. [DOI: 10.1111/j.1600-0536.2012.02061.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bertrand C, Poulon-Quintin A. Effect of temporal pulse shaping on the reduction of laser weld defects in a Pd-Ag-Sn dental alloy. Dent Mater 2010; 27:e43-50. [PMID: 21081247 DOI: 10.1016/j.dental.2010.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 07/29/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To describe the influence of pulse shaping on the behavior of a palladium-based dental alloy during laser welding and to show how its choice is effective to promote good weld quality. METHODS Single spots, weld beads and welds with 80% overlapping were performed on Pd-Ag-Sn cast plates. A pulsed Nd:Yag laser was used with a specific welding procedure using all the possibilities for pulse-shaping: (1) the square pulse shape as the default setting, (2) a rising edge slope for gradual heating, (3) a falling edge slope to slow the cooling and (4) a combination of a rising and falling edges called bridge shape. The optimization of the pulse shape is supposed to enhance weldability and produce defect-free welds (cracks, pores…) Vickers microhardness measurements were made on cross sections of the welds. RESULTS A correlation between laser welding parameters and microstructure evolution was found. Hot cracking and internal porosities were systematically detected when using rapid cooling. The presence of these types of defects was significantly reduced with the slow cooling of the molten pool. The best weld quality was obtained with the use of the bridge shape. SIGNIFICANCE The use of a slow cooling ramp is the only way to significantly reduce the presence of typical defects within the welds for this Pd-based alloy studied.
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Affiliation(s)
- C Bertrand
- Department of Prosthodontics, University Victor Segalen Bordeaux 2, France.
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Abstract
In the biomedical field, palladium has primarily been used as a component of alloys for dental prostheses. However, recent research has shown the utility of palladium alloys for devices such as vascular stents that do not distort magnetic resonance images. Dental palladium alloys may contain minor or major percentages of palladium. As a minor constituent, palladium hardens, strengthens and increases the melting range of alloys. Alloys that contain palladium as the major component also contain copper, gallium and sometimes tin to produce strong alloys with high stiffness and relatively low corrosion rates. All current evidence suggests that palladium alloys are safe, despite fears about harmful effects of low-level corrosion products during biomedical use. Recent evidence suggests that palladium poses fewer biological risks than other elements, such as nickel or silver. Hypersensitivity to palladium alone is rare, but accompanies nickel hypersensitivity 90-100% of the time. The unstable price of palladium continues to influence the use of palladium alloys in biomedicine.
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Affiliation(s)
- John C Wataha
- University of Washington School of Dentistry, Seattle, WA, USA.
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Zu J, He S, Yan F. Radiation synthesis of amino-functionalizated adsorbent and their application to palladium ions’ recovery. Radiat Phys Chem Oxf Engl 1993 2009. [DOI: 10.1016/j.radphyschem.2009.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Joska L, Poddana M, Leitner J. Corrosion behavior of palladium–silver–copper alloys in model saliva. Dent Mater 2008; 24:1009-16. [DOI: 10.1016/j.dental.2007.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 11/27/2006] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
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The mechanism of gingiva metallic pigmentations formation. Clin Oral Investig 2008; 13:1-7. [PMID: 18536944 DOI: 10.1007/s00784-008-0206-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Accepted: 05/07/2008] [Indexed: 10/22/2022]
Abstract
The occurrence of blue-grey areas in the soft tissue represents one of the problems affecting patients whose teeth have been restored using metallic materials. It is generally accepted that it is caused by mechanical penetration of a metallic material into the soft tissue. Several facts indicate that this mechanism is not general. The aim of the study was to determine an alternative mechanism of the origin of pigmentations, based on the corrosion interaction of metallic materials used in prosthodontics with the oral environment. The study was comprised of an analysis of pigment particles, determination of exposure conditions of metallic materials in vivo and laboratory evaluation of corrosion properties of the studied materials. Particles containing silver, sulphur and/or selenium could be seen in ultra-thin sections in the lamina propria gingivae. Comparison of the corrosion laboratory results with the results of in vivo measurements indicated the intensification of corrosion under these conditions. Amalgams and silver-containing alloys used for teeth restorations may release silver under the conditions of the oral cavity. The formation of soluble silver compounds in the sulcular area or in a crevice between the crown and the cast post-and-core reconstruction facilitates their transport to the soft tissue and subsequent deposition.
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Ristić L. Dental alloys and corrosion. VOJNOSANIT PREGL 2006; 63:1033-7. [PMID: 17252709 DOI: 10.2298/vsp0612033r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Ljubisa Ristić
- Vojnomedicinska akademija, Klinika za stomatologiju, Beograd, Srbija
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