scholarly journals Assessment of Galvanostatic Anodic Polarization to Accelerate the Corrosion of the Bioresorbable Magnesium Alloy WE43

2021 ◽  
Vol 11 (5) ◽  
pp. 2128
Author(s):  
Nils Wegner ◽  
Frank Walther
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Dissolution Rate ◽  
Anodic Polarization ◽  
Technical Application ◽  
Efficient Manner ◽  
Corrosion Morphology ◽  
Application Range ◽  
Alloy We43

In the field of surgery, bioresorbable magnesium is considered a promising candidate. Its low corrosion resistance, which is disadvantageous for technical application, is advantageous for surgery since the implant fully degrades in the presence of the water-based body fluids, and after a defined time the regenerating bone takes over its function again. Therefore, knowledge of the corrosion behavior over several months is essential. For this reason, an in vitro short-time testing method is developed to accelerate the corrosion progress by galvanostatic anodic polarization without influencing the macroscopic corrosion morphology. The initial corrosion rate of the magnesium alloy WE43 is calculated by detection of the hydrogen volume produced in an immersion test. In a corresponding experimental setup, a galvanostatic anodic polarization is applied with a three-electrode system. The application range for the polarization is determined based on the corrosion current density from potentiodynamic polarization. To correlate the initial corrosion rate, and accelerated dissolution rate, the corrosion morphologies of both test strategies are characterized by microscopy images, as well as energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The results demonstrate that the dissolution rate can be increased in the order of decades with the limitation of a changed corrosion morphology with increasing polarization. With this approach, it is possible to characterize and exclude new unsuitable magnesium alloys in a time-efficient manner before they are used in subsequent preclinical studies.

Features of in vitro and in vivo behaviour of magnesium alloy WE43

2018 ◽  
Vol 215 ◽  
pp. 308-311 ◽  
Author(s):  
Elena Lukyanova ◽  
Natalia Anisimova ◽  
Natalia Martynenko ◽  
Mikhail Kiselevsky ◽  
Sergey Dobatkin ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Alloy We43

Cytotoxicity of biodegradable magnesium alloy WE43 to tumor cells in vitro: Bioresorbable implants with antitumor activity?

2019 ◽  
Vol 108 (1) ◽  
pp. 167-173 ◽  
Author(s):  
Natalia Anisimova ◽  
Mikhail Kiselevskiy ◽  
Natalia Martynenko ◽  
Boris Straumal ◽  
Regine Willumeit‐Römer ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Antitumor Activity ◽  
Tumor Cells ◽  
Alloy We43 ◽  
Bioresorbable Implants ◽  
Biodegradable Magnesium

scholarly journals Mechanical Properties, Biodegradation, and Biocompatibility of Ultrafine Grained Magnesium Alloy WE43

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3627 ◽  
Author(s):  
Sergey Dobatkin ◽  
Natalia Martynenko ◽  
Natalia Anisimova ◽  
Mikhail Kiselevskiy ◽  
Dmitriy Prosvirnin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Total Elongation ◽  
Relative Mass ◽  
Ultrafine Grained ◽  
Alloy We43 ◽  
Average Size

In this work, the effect of an ultrafine-grained (UFG) structure obtained by multiaxial deformation (MAD) on the mechanical properties, fatigue strength, biodegradation, and biocompatibility in vivo of the magnesium alloy WE43 was studied. The grain refinement down to 0.93 ± 0.29 µm and the formation of Mg41Nd5 phase particles with an average size of 0.34 ± 0.21 µm were shown to raise the ultimate tensile strength to 300 MPa. Besides, MAD improved the ductility of the alloy, boosting the total elongation from 9% to 17.2%. An additional positive effect of MAD was an increase in the fatigue strength of the alloy from 90 to 165 MPa. The formation of the UFG structure also reduced the biodegradation rate of the alloy under both in vitro and in vivo conditions. The relative mass loss after six weeks of experiment was 83% and 19% in vitro and 46% and 7% in vivo for the initial and the deformed alloy, respectively. Accumulation of hydrogen and the formation of necrotic masses were observed after implantation of alloy specimens in both conditions. Despite these detrimental phenomena, the desired replacement of the implant and the surrounding cavity with new connective tissue was observed in the areas of implantation.

Microstructure and Corrosion Behavior of Hot Compressed AZ31B Magnesium Alloy Joint

2016 ◽  
Vol 849 ◽  
pp. 121-127
Author(s):  
Ya Jie Chu ◽  
Xin Chen Han ◽  
Zong Hui Yang ◽  
Xiao Quan Li
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Immersion Time ◽  
Chloride Ion ◽  
Immersion Test ◽  
Ion Concentration ◽  
Corrosion Morphology ◽  
Az31b Magnesium Alloy ◽  
Gas Tungsten Arc

The extruded AZ31B magnesium alloy plates of 4 mm thickness were butt welded using gas tungsten arc welding (GTA) process. The microstructure and corrosion behavior of the hot compressed welds were evaluated by conducting immersion test in NaCl solution at different immersion time and chloride ion concentrations. The specimens were exposed to immersion in order to characterize their corrosion rates. The corrosion morphology and pit morphology observation was carried out by scanning electron microscopy (SEM). The results showed that the corrosion rate of hot compressed magnesium alloy welds decreased with the increase in immersion time and the corrosion rate increased with the increase in chloride ion concentration, and the corrosion morphology was predominantly influenced by the distribution of β-phase.

Passivity of Chromium and Stainless Steel In Hydrofluoric Acid

CORROSION ◽  
1964 ◽  
Vol 20 (6) ◽  
pp. 179t-183t ◽  
Author(s):  
C. C. SEASTROM
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Dissolution Rate ◽  
Passive Film ◽  
Hydrofluoric Acid ◽  
Anodic Polarization ◽  
Complex Ions ◽  
Fluoride Complex ◽  
Anodic Protection

Abstract The anodic polarization of chromium and 18Cr-8Ni stainless steel has been investigated in 2 to 48 percent hydrofluoric acid, 40 percent sulfuric acid, and in a solution containing 5 percent hydrofluoric acid and 40 percent sulfuric acid. Chromium can be anodically protected in hydrofluoric acid. The corrosion rate of stainless steel in hydrofluoric acid can be reduced by anodic protection but less than is possible in sulfuric acid. The dissolution rate of passive stainless steel in 5 percent hydrofluoric acid plus 40 percent sulfuric acid is similar to the rate in 5 percent hydrofluoric acid. The breakdown of the passive film on stainless steel probably is accelerated by the formation of stable ferric fluoride complex ions.

Corrosion Behavior of AZ61 Magnesium Alloys in NaCl Solution

2011 ◽  
Vol 239-242 ◽  
pp. 2240-2243
Author(s):  
Yue Sheng Chai ◽  
Li Na Wang ◽  
Gang Sun ◽  
Shu Li Sun ◽  
Min Gang Zhang
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Magnesium Alloys ◽  
Corrosion Behavior ◽  
Chloride Concentration ◽  
Ion Concentration ◽  
Etching Time ◽  
Protective Film ◽  
Corrosion Morphology ◽  
Az61 Magnesium Alloy

Magnesium alloys are used widely because of its good performance. However, its practical application is restricted by low corrosion resistance. In this study, the effects of corrosion time and NaCl concentration on the corrosion behavior of AZ61 magnesium alloy were investigated from the corrosion morphology and the corrosion rate. These results have displayed that the corrosion rate of AZ61 magnesium alloy decreases with the increasing etching time. Meanwhile, the corrosion rate of AZ61 magnesium alloy increases with the increasing sodium chloride concentration. This is mainly because that the Cl- ion in the solution destroys the protective film on the surface of magnesium alloy and the high Cl- ion concentration accelerates the corrosion rate.

In Vitro Corrosion and Biocompatibility of Coated MgCa1.0 Magnesium Alloys

2011 ◽  
Vol 690 ◽  
pp. 409-412
Author(s):  
Paul Rosemann ◽  
Susanne Bender ◽  
Andreas Heyn ◽  
Jürgen Schmidt
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Ph Value ◽  
Corrosion Behaviour ◽  
Dip Coating ◽  
Chemical Oxidation ◽  
Essential Elements ◽  
Noise Measurements

As bio-absorbable implant material the magnesium alloy Mg-1Ca is able to degrade in-vivo. The mechanical properties of this alloy are similar to those of human bone; both Mg and Ca are essential elements in human body. The main problem is the high corrosion rate of this alloy. Two coating systems based on plasma-chemical oxidation and an organic dip coating are applied onto MgCa1.0 magnesium alloy in order to slow down the corrosion rate. The corrosion behaviour of the coated alloys was investigated with electrochemical noise measurements. The influence of hydrogen evolution and increasing pH-value on the cytotoxicity was examined. The results of these investigations suggest that a combination of both coating systems leads to promising degradation properties.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Influence of β-Cyclodextrin and Hydroxypropyl-β-Cyclodextrin on Enhancement of Solubility and Dissolution of Isradipine

2017 ◽  
Vol 10 (3) ◽  
pp. 3752-3757
Author(s):  
Narendar D ◽  
Ettireddy S
Keyword(s):  
Inclusion Complex ◽  
Dissolution Rate ◽  
Solid Dispersions ◽  
Physical Stability ◽  
Molecular Complexes ◽  
In Vitro Dissolution ◽  
Molar Ratio ◽  
Phase Solubility ◽  
Cyclodextrin Complexation

The content of this investigation was to study the influence of β-cyclodextrin and hydroxy propyl-β-cyclodextrin complexation on enhancement of solubility and dissolution rate of isradipine. Based on preliminary phase solubility studies, solid complexes prepared by freeze drying method in 1:1 molar ratio were selected and characterized by DSC for confirmation of complex formation. Prepared solid dispersions were evaluated for drug content, solubility and in vitro dissolution. The physical stability of optimized formulation was studied at refrigerated and room temperature for 2 months. Solid state characterization of optimized complex performed by DSC and XRD studies.  Dissolution rate of isradipine was increased compared with pure drug and more with HP-β-CD inclusion complex than β-CD. DSC and XRD analyzes that drug was in amorphous form, when the drug was incorporated as isradipine β-CD and HP-β-CD inclusion complex. Stability studies resulted in low or no variations in the percentage of complexation efficiency suggesting good stability of molecular complexes. The results conclusively demonstrated that the enhancement of solubility and dissolution rate of isradipine by drug-cyclodextrin complexation was achieved.   

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