scholarly journals Assessment of corrosion resistance of cast cobalt- and nickel-chromium dental alloys in acidic environments

2017 ◽  
Vol 16 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Sven Mercieca ◽  
Malcolm Caligari Conti ◽  
Joseph Buhagiar ◽  
Josette Camilleri
Keyword(s):  
Corrosion Resistance ◽  
Inductively Coupled Plasma ◽  
Artificial Saliva ◽  
Base Material ◽  
Corrosion Current ◽  
Open Circuit ◽  
Cobalt Chromium ◽  
Corrosion Properties ◽  
Inductively Coupled ◽  
Nickel Chromium

Background: The aim of this study was to compare the degradation resistance of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys used as a base material for partial dentures in contact with saliva. Methods: Wiron® 99 and Wironit Extra-Hard® were selected as representative casting alloys for Ni-Cr and Co-Cr alloys, respectively. The alloys were tested in contact with deionized water, artificial saliva and acidified artificial saliva. Material characterization was performed by X-ray diffractometry (XRD) and microhardness and nanohardness testing. The corrosion properties of the materials were then analyzed using open circuit potential analysis and potentiodynamic analysis. Alloy leaching in solution was assessed by inductively coupled plasma mass spectrometry techniques. Results: Co-Cr alloy was more stable than the Ni-Cr alloy in all solutions tested. Leaching of nickel and corrosion attack was higher in Ni-Cr alloy in artificial saliva compared with the acidified saliva. The corrosion resistance of the Co-Cr alloy was seen to be superior to that of the Ni-Cr alloy, with the former exhibiting a lower corrosion current in all test solutions. Microstructural topographical changes were observed for Ni-Cr alloy in contact with artificial saliva. The Ni-Cr alloy exhibited microstructural changes and lower corrosion resistance in artificial saliva. The acidic changes did not enhance the alloy degradation. Conclusions: Ni-Cr alloys are unstable in solution and leach nickel. Co-Cr alloys should be preferred for clinical use.

scholarly journals Experimental Study Regarding the Behavior at Different pH of Two Types of Co-Cr Alloys Used for Prosthetic Restorations

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4635
Author(s):  
Farah Bechir ◽  
Simona Maria Bataga ◽  
Elena Ungureanu ◽  
Diana Maria Vranceanu ◽  
Mariana Pacurar ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Ph Value ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Open Circuit ◽  
Dental Alloys ◽  
Cobalt Chromium ◽  
Electrochemical Parameters

Cobalt-chromium (Co-Cr) alloys are widely utilized in dentistry. The salivary pH is a significant factor, which affects the characteristics and the behavior of dental alloys through corrosion. This study aimed to evaluate the corrosion behavior in artificial saliva with different pH values (3, 5.7, and 7.6) of two commercial Co-Cr dental alloys manufactured by casting and by milling. Corrosion resistance was determined by the polarization resistance technique, and the tests were carried out at 37 ± 1 °C, in Carter Brugirard artificial saliva. After the electrochemical parameters, it can be stated that the cast Co-Cr alloy has the lowest corrosion current density, the highest polarization resistance, and the lowest speed of corrosion in artificial saliva with pH = 7.6. In the case of milled Co-Cr alloy, the same behavior was observed, but in artificial saliva with pH = 5.7, it recorded the most electropositive values of open circuit potential and corrosion potential. Although both cast and milled Co-Cr alloys presented a poorer corrosion resistance in artificial saliva with a more acidic pH value, the milled Co-Cr alloy had better corrosion behavior, making this alloy a better option for the prosthetic treatment of patients suffering from GERD.

scholarly journals Experimental evaluation of corrosion resistance of the alloys used in the fixed dental prosthesis

2015 ◽  
Vol 61 (2) ◽  
pp. 117-120
Author(s):  
Costin Coman ◽  
◽  
Raluca Monica Comăneanu ◽  
Violeta Hâncu ◽  
Horia Mihail Barbu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Applied Research ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Open Circuit ◽  
Metal Alloys ◽  
Fixed Dental Prosthesis

Objectives. In this study we evaluated corrosion resistance of three types of metal alloys (two NiCr and one CoCr). Methods. Samples (coded A, B, C) of circular shape, with dimensions 13 x 1.5 mm, sanded and polished, were introduced in Fusayama Meyer artificial saliva at pH 5.2 and 37 ± 0.5°C and tested in terms of corrosion resistance with a potentiostat/galvanostat (model 4000 PARSTAT, Princeton Applied Research). Results. Open circuit potential EOC [mV] ranged between 21.316 and 5.75. Corrosion potential Ecor [mV] was between -73.536 and -395.662, and the corrosion current density icor [A/cm2] was between 1.237 x 10-6 and 905.13 x 10-9. Conclusion. The best corrosion behavior in Fusayama Meyer artificial saliva at pH 5.2 and at a temperature of 37 ± 0.5°C is the alloy A, followed by the alloy C.

scholarly journals Comparative Analysis of the Corrosion Resistance of Titanium Alloys Intended to Come into Direct or Prolonged Contact with Live Tissues

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2841 ◽  
Author(s):  
Florina Ionescu ◽  
Lucien Reclaru ◽  
Lavinia Cosmina Ardelean ◽  
Andreas Blatter
Keyword(s):  
Corrosion Resistance ◽  
Inductively Coupled Plasma ◽  
Surface Oxidation ◽  
Melting Process ◽  
Open Circuit ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Electrochemical Tests ◽  
Inductively Coupled ◽  
Prolonged Contact

The evaluation of the biological safety and degradation of materials is quite important for risk assessment in various biomedical applications. In this study, two procedures were followed to characterize the corrosion resistance of different Ti-based alloys. The first one consisted of performing specific electrochemical tests (open circuit potential, linear resistance polarization, Tafel plots, potentiodynamic polarization) in order to highlight their behavior to the general and localized corrosion. The static and dynamic fatigue cycles combined with crevice corrosion conducted on a new prototype have completed the study. The second procedure followed was a cations extraction investigation (by inductively coupled plasma mass spectrometry) in order to verify the ionic permeability of the oxides layers formed on the surfaces. Optical and scanning electron microscopy were used for surface analysis. It was noticed that in these two electrolytes, the bulk Ti-based alloys presented an almost similar general corrosion behavior. The small differences of behavior for Ti6Al4V scaffolds were correlated to the surface oxidation and roughness (owing to the selective laser melting process). The Ti alloys presented no traces of localized corrosion at the end of the test. The fatigue cycles revealed that a strong and adhesive oxides film was formed during the static cycles (difficult to remove even during the depassivation steps). The concentration of cations released was at the detection limit, revealing very good passivation films, in adequacy with the all the other results.

Effect of Ozone on Corrosion Behavior of a Cobalt–Chromium Alloy Used in Removable Partial Denture Framework: An In Vitro Study

2021 ◽  
pp. 232020682110157
Author(s):  
Abdolrasoul Rangrazi ◽  
Amirtaher Mirmortazavi ◽  
Reyhaneh Imani ◽  
Davood Nodehi
Keyword(s):  
Corrosion Resistance ◽  
Inductively Coupled Plasma ◽  
In Vitro Study ◽  
Optical Emission ◽  
Cobalt Chromium ◽  
Inductively Coupled ◽  
Significant Difference ◽  
Polarization Test ◽  
Ozonated Water

Aim: The aim of this study was to evaluate the effect of the ozonated water on corrosion of a cobalt–chromium (Co-Cr)-based alloy, which is applied for the fabrication of metal frameworks of removable partial dentures. Materials and Methods: In this in vitro study, a total of 30 disk-shaped samples of a Co-Cr alloy were papered and randomly divided into two groups of 15 specimens. In group 1 (control), the specimens were stored in distilled water (DW), and in group 2, the specimens were stored in ozonated water. Around 90 immersions were performed, and the weight change of each specimen was determined. The ion release was analyzed using an inductively coupled plasma-optical emission spectrophotometer. The potentiodynamic polarization test was performed for each group to assess the corrosion resistance of the Co-Cr alloy. The statistical analysis was performed using SPSS version 22. Data were analyzed by independent samples’ t-test. Results: The results showed no significant difference between the weight changes of the two groups. The test using an inductively coupled plasma-optical emission spectrophotometer demonstrated no significant difference between the groups in Co and Cr ions release. In the potentiodynamic polarization test, both groups present similar corrosion behavior, and ozonated water has no deleterious effect on the corrosion resistance and passive range of the Co-Cr alloy compared to DW. Conclusion: As compared to DW, ozonated water has no significant deleterious effect on the corrosion resistance of the Co-Cr frameworks and can be used for cleaning the removable partial dentures.

scholarly journals Corrosion behaviour of an AlZnSnSrGa alloy in aqueous solutions of NaCl and Na2So4

2000 ◽  
Vol 65 (1) ◽  
pp. 73-81
Author(s):  
P. Zivkovic ◽  
J. Pjescic ◽  
S. Mentus
Keyword(s):  
Corrosion Rate ◽  
Aqueous Solutions ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Behaviour ◽  
Base Material ◽  
Corrosion Current ◽  
Open Circuit ◽  
Base Metals ◽  
Aluminium Plant

The alloy composed of Al(95.53%), Zn(2.85%), Sn(0.515%), Ga(0.1%) and Sr(0.009%), with the weight percents in the parentheses, was prepared by melting, using Al(99.84%), a product of the Aluminium Plant-Podgorica, as the base material. The corrosion behaviour of this alloy was tested in relation to the behaviour of the base metals, by both open curcuit potential and polarization resistance methods, in aqueous solutions of both NaCl and Na2SO4, the concentration of which varied within the range 0.00051 - 0.51 mol dm -3. Over the whole salt concentration ranges, the corrosion parameters indicate that the corrosion rate of the alloy is significantly higher than the rate of the base material. For instance, for the concentration range 0.00051 - 0.51 mol dm -3 , the stationary open circuit potentials, related to SCE, in NaCl solutions were - 1.200 to - 1.460 V for the alloy and - 0.693 to - 0.920 V for Al, while in Na2SO4 solutions, the stationary open circuit potentials were - 1.190 to - 1.465V for the alloy and - 0.780 to - 0.860V for Al. At the same time, the corrosion current density in NaCl solutions varied within 11-89 mA cm -2 for the alloy and 0.35 - 0.80 for Al, while in Na2SO4 solutions it amounted to 5.7.52 mA cm -2 for the alloy and 0.28 - 0.88 mA cm -2 for Al.

scholarly journals Mechanical and Corrosion Properties of Mg-Based Alloys with Gd Addition

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1775 ◽  
Author(s):  
Aneta Kania ◽  
Ryszard Nowosielski ◽  
Agnieszka Gawlas-Mucha ◽  
Rafał Babilas
Keyword(s):  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Orthopedic Implants ◽  
Corrosion Current ◽  
Medical Application ◽  
Open Circuit ◽  
Dendritic Microstructure ◽  
Corrosion Properties ◽  
Electrochemical Parameters ◽  
Mechanical And Corrosion Properties

Magnesium alloys with rare earth metals are very attractive materials for medical application because of satisfactory mechanical properties. Nevertheless, low corrosion resistance is an obstacle in the use of Mg alloys as resorbable orthopedic implants. The paper presents results of mechanical and corrosion properties of MgCa5-xZn1Gdx (x = 1, 2, and 3 wt. %) alloys. Based on the microscopic observations it was stated that the studied alloys show a dendritic microstructure with interdendritic solute rich regions. The phase analysis reveals an occurrence of α-Mg and Mg2Ca, Ca2Mg6Zn3 phases that are thermodynamic predictions, and stated Mg26Zn59Gd7 phases in MgCa5-xZn1Gdx (x = 1, 2, and 3 wt. %) alloys. The Mg26Zn59Gd7 phases are visible as lamellar precipitations along interdendritic regions. It was confirmed that an increase of Gd content from 1 to 3 wt. % improves ultimate tensile (Rm; from 74 to 89 MPa) and compressive strength (Rc; from 184 to 221 MPa). Moreover, the studied alloys are active in Ringer’s solution. They are characterized by an increase of corrosion potential (Ecorr) of about 150 mV in comparison with values of open circuit potential (EOCP). The best electrochemical parameters (e.g., corrosion current density, icorr, polarization resistance, Rp, and Ecorr) were obtained for the MgCa3Zn1Gd2 alloy.

Corrosion Behavior of Ti-7 Wt.% Mn Alloy in Artificial Saliva

2020 ◽  
Vol 835 ◽  
pp. 288-296 ◽  
Author(s):  
Adel Attia ◽  
Lobna A. Khorshed ◽  
Lamiaa Z. Mohamed ◽  
Mohammed A. Gepreel
Keyword(s):  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Annealed Sample ◽  
Open Circuit ◽  
Corrosion Properties ◽  
X Ray ◽  
Specific Strength ◽  
Corrosion Resistance Property ◽  
Cold Rolled ◽  
Dental Applications

Ti-Mn alloy has a high specific strength, excellent cold workability and good biocompatibility. A cold rolled Ti-7 wt.% Mn was compared to annealed sample at 900°C for 10 min and the corrosion resistance property was tested in artificial saliva solution (AS). The Ti-7 wt.% Mn alloys (cold rolled and annealed) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX) and compared to pure Ti. Simultaneously, the alloys tested in the AS solution for up to 28 days mainly by following the open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS), SEM and EDX. Annealed Ti-7wt.% Mn showed good corrosion properties similar to that of pure Ti, hence the new Ti-7wt.%Mn alloy have higher specific strength than pure Ti, yet showed same corrosion properties which favor implanted dental applications.

scholarly journals Development of a Routine Method for the Determination of Trace Metals in Whole Blood by Magnetic Sector Inductively Coupled Plasma Mass Spectrometry with Particular Relevance to Patients with Total Hip and Knee Arthroplasty

2001 ◽  
Vol 47 (2) ◽  
pp. 275-280 ◽  
Author(s):  
C Patrick Case ◽  
Lyndon Ellis ◽  
Justine C Turner ◽  
Ben Fairman
Keyword(s):  
Sample Preparation ◽  
Whole Blood ◽  
Inductively Coupled Plasma ◽  
Cobalt Chromium ◽  
Blood Samples ◽  
Magnetic Sector ◽  
Total Hip ◽  
Inductively Coupled ◽  
Joint Replacement Surgery ◽  
Polyatomic Interferences

Abstract Background: Joint-replacement surgery has revolutionized the treatment of osteoarthritis and is still the most effective therapy. A recent clinical trend reintroducing metal-on-metal bearing surfaces has in turn stimulated a requirement for accurate measurement of the concentrations of relevant metals in both pre- and postoperative patients. Thus, there is a need for cost-effective, multielement methods for trace metal analysis in whole blood to monitor possible increases in wear metal concentrations. Methods: A method was developed to allow routine analysis of whole blood samples for molybdenum, cobalt, chromium, and nickel. Sample preparation consisted of a simple 1:10 dilution of whole blood with a solution of 10 mL/L Triton X-100, 0.0002 mol/L EDTA, and 0.01 mol/L ammonium hydroxide. Final determination was performed by a double-focusing magnetic sector inductively coupled plasma mass spectrometer operated in medium-resolution mode (resolution, 3400). Online addition of rhodium was used for internal standardization. Results: Detection limits in whole blood were 0.06 μg/L for chromium, cobalt, and molybdenum and 0.30 μg/L for nickel. Base concentrations of 0.22, 0.17, 0.62, and 0.99 μg/L for chromium, cobalt, molybdenum, and nickel, respectively, in whole blood have been found. Polyatomic interferences on all four elements have been shown to be resolved from the analyte masses by use of a resolution of >3000. Conclusions: The simple, rapid method of sample preparation is effective in minimizing potential contamination and enables 60 samples (run time, 8 h) to be analyzed before cleaning the instrument is necessary. A resolution >3000 was sufficient to separate polyatomic interferences from the masses of interest. The method was used to analyze a large number of blood samples taken from primary patients awaiting total hip arthroplasty. The method is sensitive enough to provide base concentrations for chromium, cobalt, and molybdenum in whole blood. The results for nickel were compromised by high signals for blank samples.

INFLUENCE OF SURFACTANTS ON THE CORROSION PROPERTIES OF CHROMIUM-FREE ELECTROLESS NICKEL DEPOSIT ON MAGNESIUM ALLOY

2012 ◽  
Vol 19 (03) ◽  
pp. 1250025 ◽  
Author(s):  
JOTHI SUDAGAR ◽  
RUAN DEWEN ◽  
YAQIN LIANG ◽  
RASU ELANSEZHIAN ◽  
JIANSHE LIAN
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Immersion Test ◽  
Electrochemical Polarization ◽  
Nickel Deposit ◽  
Corrosion Properties ◽  
Positive Direction ◽  
Polarization Test

Influence of surfactants on the corrosion properties of chromium-free electroless nickel deposit were investigated on AZ91D magnesium alloy. The corrosion tests were carried out by immersion test (1 M HCl) and electrochemical polarization test (3.5 wt% NaCl ). The surfactants in the electroless nickel bath increases the corrosion resistance properties of the deposit on the magnesium alloy. In addition, smoothness and amorphous plus nano-crystalline phase were increased and accounted for the significant corrosion resistance. As a consequence, the corrosion potential moved towards the positive direction and the corrosion current density decreased. The immersion tests also provided the same trend as that of electrochemical polarization test. On the whole, the study concluded that corrosion resistance was enhanced by including a surfactant in the electroless deposits on magnesium alloy.

Tribological and Corrosive Properties of Tin/AlN Multilayer Film

2012 ◽  
Vol 560-561 ◽  
pp. 837-841
Author(s):  
Pu Hong Tang ◽  
Jie Mao ◽  
Chong You Feng
Keyword(s):  
Corrosion Resistance ◽  
Coefficient Of Friction ◽  
Gas Flow ◽  
Multilayer Film ◽  
Corrosion Current ◽  
Multilayer Films ◽  
Nitrogen Gas ◽  
Corrosion Properties ◽  
Wear Rates ◽  
The Coefficient Of Friction

TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.

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