scholarly journals Analysis and Comparison of the Corrosive Behavior of Nickel-Based and Cobalt-Based Dental Alloys

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4949
Author(s):  
Carmen Marina Garcia-Falcon ◽  
Tomas Gil-Lopez ◽  
Amparo Verdu-Vazquez ◽  
Julia Claudia Mirza-Rosca
Keyword(s):  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Dental Materials ◽  
Electrochemical Treatment ◽  
Ringer Solution ◽  
Passive Layer ◽  
Metal Alloys ◽  
Dental Alloys ◽  
Potentiostatic Polarization ◽  
The Stability

Nickel-based and cobalt-based metal alloys are frequently used in dentistry. The introduction of various elements in the alloy changes its characteristics, and a thorough study of each alloy should be completed to determine its appropriate corrosion resistance and biocompatibility in contact with physiological fluids. There are scarce investigations on these widely used dental alloys in Ringer solution, and findings in this research bring new experimental data and information. The present study evaluated and compared the corrosion behavior of six NiCr- and two CoCr-based dental materials in Ringer solution, using the following techniques: potentiostatic polarization curves (chronoamperometry), microstructural analysis, and EIS (electrochemical impedance spectroscopy). The results obtained in this investigation showed that in the NiCr-based specimens Ni4, Ni5, and Ni6 the stability of the passive layer was destroyed after polarization and a development and growth of stable pits was found in the microstructural analysis after electrochemical treatment. In terms of susceptibility to corrosion, two different groups of specimens were derived from this investigation. A first group which included the two CoCr (Co1 and Co2) and three of the six NiCr alloys studied (Ni1, Ni2, and Ni3). A second group with the other NiCr alloys investigated Ni4, Ni5, and Ni6.

scholarly journals Corrosion behavior in Ringer solution of several commercially used metal alloys

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Carmen Marina Garcia-Falcon ◽  
Tomas Gil-Lopez ◽  
Amparo Verdu-Vazquez ◽  
Julia Claudia Mirza-Rosca
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Dental Materials ◽  
Ringer Solution ◽  
Open Circuit ◽  
Metal Alloys ◽  
Cylindrical Shape ◽  
Content Type ◽  
Biological Safety

Purpose This paper aims to analyze the corrosion behavior in Ringer solution of six commercially used Ni-based alloys that are present and commonly used as metallic biomaterials. Design/methodology/approach The specimens were received in the form of cylindrical ingots and were cut to get five samples of each brand with a cylindrical shape of 2 mm height to conduct the study. In this scientific research, the following techniques were used: open circuit potential, potentiodynamic polarization studies, and electrochemical impedance spectroscopy. Findings The study findings revealed the passivation tendency of the different specimens. Additionally, when the materials were compared, it was discovered that the decisive factor for high corrosion resistance was the chromium concentration. However, with similar chromium content, the stronger concentration in molybdenum increased the resistance. According to the results obtained in this investigation, the biological safety of the dental materials studied in Ringer solution was considered very high for specimens 1 and 2, and adequate for the other samples. Originality/value Metal alloys used as biomaterials in contact with the human body should be deeply investigated to make sure they are biocompatible and do not cause any harm. The corrosion resistance of an alloy is the most important characteristic for its biological safety, as all problems arise because of the corrosion process. There is scarce investigation in these Ni-based dental biomaterials, and none found in these commercially used dental materials in Ringer solution.

scholarly journals Characterization of the passive films on electrodeposited Fe-Ni-Cr alloys in borate solution at pH 8.4

2007 ◽  
Vol 5 (4) ◽  
pp. 931-950 ◽  
Author(s):  
Laura Sziráki ◽  
Ernő Kuzmann ◽  
Colin Chisholm ◽  
Mahmoud El-Sharif ◽  
Lilla Bóbics ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Passive Layer ◽  
Passive Films ◽  
Corrosion Properties ◽  
Nickel Chromium ◽  
Iron Nickel ◽  
The Stability ◽  
Dissolution Corrosion ◽  
Borate Solution

AbstractThe corrosion properties of the passive layers formed on iron-nickel-chromium electrodeposits of Fe29Ni51Cr20 were investigated in 0.3 M borate solution at a‘ pH of 8.4. On the basis of measurements by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy, a low passive dissolution/corrosion rate was identified for the electrodeposited Fe-Ni-Cr alloys due to the nature of the established corrosion layer. The stability of this passive layer was further enhanced after corrosion under oxidizing conditions. Mössbauer spectroscopic measurements confirmed the existence of a thin passive layer on the amorphous electrodeposits.

Microstructural and electrochemical characterization of hydroxyapatite-coated Ti6Al4V alloy for medical implants

2008 ◽  
Vol 23 (3) ◽  
pp. 768-779 ◽  
Author(s):  
Jianhui Xie ◽  
Ben Li Luan
Keyword(s):  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Composite Layer ◽  
Ti6al4v Alloy ◽  
Electrochemical Measurements ◽  
High Tendency ◽  
Coated Substrate ◽  
The Stability ◽  
Hank’S Solution ◽  
New Formation

The in vitro behaviors of the etched, electrochemically anodized, and hydroxyapatite (HA)-coated Ti6Al4V alloys were investigated through microstructural analysis, electrochemical measurements, and immersion tests in the Hank’s solution. A nanometer-scale, bonelike porous structure with a layer of TiO2 on top was formed during the anodization process. The surface of the coated substrate was composed of a thin TiO2 layer adjacent to the substrate, a thick monolithic HA on the outside, and a composite layer of TiO2 and HA in the middle. The anodization significantly improved the stability of the Ti6Al4V alloy in Hank’s solution due to a layer of TiO2 formed on the surface. The precoated HA further improved the stability of the Ti6Al4V alloy due to a composite layer of TiO2 and HA. The barrier layer of the composite of TiO2 and HA was suggested by the capacitive behavior of the HA-coated substrate in the electrochemical impedance spectroscopy. The electrochemical measurements implied a high tendency for the new formation of HA on the precoated HA and the anodized substrates, which was confirmed through the immersion tests. The newly formed HA on the anodized substrate was scattered over the entire surface. The newly formed HA on the HA-precoated surface mingled with the precoated HA, and gradually a new layer of HA was formed on top. These proved the favorable condition of the anodized surface as a prerequisite step for coating HA and the conductive promotion of new HA formation on the precoated surface. The new formation of HA during the immersion might suggest that artificial joints pretreated through anodization and HA coating could induce strong bonding to the bone due to the easy growth of new HA.

An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Melt Spinning ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
Microstructural Analysis ◽  
Alloy System ◽  
Antimony Content ◽  
The Stability ◽  
Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 

Study of Electrochemical Behavior of Some Dental Alloys

2018 ◽  
Vol 69 (6) ◽  
pp. 1598-1602
Author(s):  
Alice Arina Ciocan Pendefunda ◽  
Constanta Mocanu ◽  
Doriana Agop Forna ◽  
Cristina Iordache ◽  
Elena Luca ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Electrochemical Behavior ◽  
Base Alloy ◽  
Artificial Saliva ◽  
Surface Condition ◽  
Continuous Process ◽  
Metal Alloys ◽  
Alloy Surface ◽  
Dental Alloys ◽  
Dental Restorations

The purpose of the study is to investigate the electrochemical behavior of two dental alloys: palladium alloy (Palidor) and Ni-Cr alloy (Verasoft) in three types of artificial saliva. Determination of corrosion potential and recording of linear and cyclic polarization curves were performed with PGP201 potentiostat (VoltaLab 21- Radelkis Copenhagen. In order to study the modifications produced on the surface of the electrodes, a complex optical microscope MC 1 research type (IOR, Romania) was used, adapted to a digital camera, which was connected to a computer for the digital acquisition of images . Two metal alloys based on Ag-Pd and Ni-Cr were used for the experiments. The materials used came from different types of dental restorations removed from the oral cavity of the patients after a 5-15 years period. As corrosion environments, three artificial saliva were used: Fusayama, Afnor and Rondelli. The Pd-Ag dental alloy exhibits a very good corrosion resistance and the treatment in the Afnor saliva does not affect the surface of the alloy. Electrochemical behavior in Fusayama-Meyer�s saliva of the alloy surface results in a series of spots representing deposits of insoluble salts resulting from the oxidation process, while in the Rondelli saliva there is a series of small corrosion points on the alloy surface. The behavior of the Verasoft alloy in the Afnor and Rondelli saliva is similar; In both solutions, the potential breakthroughs are very close, but in Fusayama-Meyer�s saliva, the potential for initiation of corrosion points is very low (206 mV), a potential that can be encountered in the oral cavity. All metals and metal alloys, even the noble and semi-precious ones, are susceptible to corrosion, forming compounds with properties different from those of the metal or base alloy, which change their surface condition. Metallic dental restorations are permanently affected by the factors of the oral environment (physical-mechanical, chemical and biological), being subjected to a continuous process of degradation.

scholarly journals Influence of HAP on the Morpho-Structural Properties and Corrosion Resistance of ZrO2-Based Composites for Biomedical Applications

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 202
Author(s):  
Réka Barabás ◽  
Carmen Ioana Fort ◽  
Graziella Liana Turdean ◽  
Liliana Bizo
Keyword(s):  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Synergetic Effect ◽  
Composite Layer ◽  
Charge Transfer Resistance ◽  
Processing Route ◽  
Dental Alloys ◽  
Metallic Electrode ◽  
Transfer Resistance ◽  
X Ray

In the present work, ZrO2-based composites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP) to the inert zirconia. The composites were synthesized by the conventional ceramic processing route and morpho-structurally analyzed by X-ray powder diffraction (XRPD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two metallic dental alloys (i.e., Ni–Cr and Co–Cr) coated with a chitosan (Chit) membrane containing the prepared composites were exposed to aerated artificial saliva solutions of different pHs (i.e., 4.3, 5, 6) and the corrosion resistances were investigated by electrochemical impedance spectroscopy technique. The obtained results using the two investigated metallic dental alloys shown quasi-similar anticorrosive properties, having quasi-similar charge transfer resistance, when coated with different ZrO2-based composites. This behavior could be explained by the synergetic effect between the diffusion process through the Chit-composite layer and the roughness of the metallic electrode surface.

scholarly journals Zn-Co-CeO2 vs. Zn-Co Coatings: Effect of CeO2 Sol in the Enhancement of the Corrosion Performance of Electrodeposited Composite Coatings

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 704
Author(s):  
Marija Riđošić ◽  
Nebojša D. Nikolić ◽  
Asier Salicio-Paz ◽  
Eva García-Lecina ◽  
Ljiljana S. Živković ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Healing Rate ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Self Healing ◽  
Kelvin Probe ◽  
Artificial Defect ◽  
Volta Potential ◽  
Superior Corrosion Resistance ◽  
The Stability

Electrodeposition and characterization of novel ceria-doped Zn-Co composite coatings was the main goal of this research. Electrodeposited composite coatings were compared to pure Zn-Co coatings obtained under the same conditions. The effect of two ceria sources, powder and home-made sol, on the morphology and corrosion resistance of the composite coatings was determined. During the electrodeposition process the plating solution was successfully agitated in an ultrasound bath. The source of the particles was found to influence the stability and dispersity of plating solutions. The application of ceria sol resulted in an increase of the ceria content in the resulting coating and favored the refinement from cauliflower-like morphology (Zn-Co) to uniform and compact coral-like structure (Zn-Co-CeO2 sol). The corrosion resistance of the composite coatings was enhanced compared to bare Zn-Co as evidenced by electrochemical impedance spectroscopy and scanning Kelvin probe results. Zn-Co doped with ceria particles originating from ceria sol exhibited superior corrosion resistance compared to Zn-Co-CeO2 (powder) coatings. The self-healing rate of artificial defect was calculated based on measured Volta potential difference for which Zn-Co-CeO2 (sol) coatings exhibited a self-healing rate of 73.28% in a chloride-rich environment.

scholarly journals Effect of Molybdenum Content on the Corrosion and Microstructure of Low-Ni, Co-Free Maraging Steels

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray ◽  
Maraging Steels ◽  
Eds Analysis ◽  
Electroslag Refining

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.

Effect of Nano-Silica Volume Reinforcement on the Microstructure, Mechanical, Phase Distribution and Electrochemical Behavior of Pre-Alloyed Titanium-Nickel (Ti-Ni) Powder

2021 ◽  
Vol 875 ◽  
pp. 60-69
Author(s):  
Syed Abbas Raza ◽  
Muhammad Imran Khan ◽  
Mairaj Ahmad ◽  
Danish Tahir ◽  
Asim Iltaf ◽  
...  
Keyword(s):  
Phase Distribution ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Microstructural Analysis ◽  
Furnace Cool ◽  
Neutral Salt ◽  
Nano Silica ◽  
Corrosion Properties ◽  
Volume Percentage ◽  
Titanium Nickel

Titanium-Nickel pre-alloyed powder was reinforced with Nano-Silica in 2%, 4% , 6% and 8 wt. % due to effectiveness of Nanoscale ceramic Reinforcement in improving the properties of Metals and Alloys. The compositions of the Pre-Alloyed powders and Nano Silica Approximately 50 nm in diameter and spherical in shape were weighed and mixed in Planetary Ball Mill followed by compaction at 50 MPa using a Uniaxial Compaction machine The green pellets obtained were sintered in Argon Environment for 5 hrs and allowed to furnace cool. The pellets were then sectioned through their cross-section for slices 3 mm thick followed by Cold-mounting and Soldering followed by cold mounting additionally. The Samples were analyzed via X-Ray Diffraction (XRD) for phase distribution as a function of variation in nano-Silica reinforcements and Microstructural analysis was performed via Optical Microscope. The effect of Volume percentage on the densification was determined via Archimedes principle and Micro-Vickers hardness was used for mechanical Evaluation. The Electrochemical Properties were evaluated using Potentio-Dynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) in neutral salt solution (3.5% NaCl). The results indicated increasing dissolution of the TiNi phase into intermetallic Titanium-rich and Ni-rich phases in the matrix and hardening due to the Nano-Silica effect of Grain Boundary impingement and phase dissolution of Equiatomic phase and mixed behavior in Corrosion properties as determined by the electrochemical techniques whereas densification decreased due to poor plasticity of Nano-Silica and hinderance in diffusion during the sintering process.

scholarly journals Investigation on the Thermodynamic Stability of Nanocrystalline W-Based Alloys: A Combined Theoretical and Experimental Approach

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7179
Author(s):  
Francesco Torre ◽  
Claudio Mingazzini ◽  
Daniele Mirabile Gattia ◽  
Teodor Huminiuc ◽  
Antonio Rinaldi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermodynamic Stability ◽  
Experimental Approach ◽  
Metal Alloys ◽  
Model Predictions ◽  
The Stability ◽  
Experimental Findings ◽  
Constituent Elements ◽  
Segregated Structure ◽  
Nanostructured Metal

The stability of nanostructured metal alloys is currently being extensively investigated, and several mathematical models have been developed to describe the thermodynamics of these systems. However, model capability in terms of thermal stability predictions strongly relies on grain boundary-related parameters that are difficult to measure or estimate accurately. To overcome this limitation, a novel theoretical approach is proposed and adopted in this work to identify W-based nanocrystalline alloys which are potentially able to show thermodynamic stability. A comparison between model outcomes and experimental findings is reported for two selected alloys, namely W-Ag and W-Al. Experimental results clearly highlight that W-Ag mixtures retain a segregated structure on relatively coarse length scales even after prolonged mechanical treatments. Moreover, annealing at moderate temperatures readily induces demixing of the constituent elements. In contrast, homogeneous nanostructured W-Al solid solutions are obtained by ball milling of elemental powders. These alloys show enhanced thermal stability with respect to pure W even at high homologous temperatures. Experimental evidences agree with model predictions for both the investigated systems.

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