Electrochemical Corrosion Behavior of AZ80 Magnesium Alloy Tube Fabricated by Hydrostatic Extrusion

2014 ◽  
Vol 624 ◽  
pp. 77-81
Author(s):  
Zhi Lin Wu ◽  
Duo Xiang Wu ◽  
Ren Shu Yuan ◽  
Lei Zhao ◽  
Yan Bao Zhao
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Hydrostatic Extrusion ◽  
Polarization Curves ◽  
Az80 Magnesium Alloy

The corrosion behavior of hydrostatic extruded tube AZ80 magnesium alloy was investigated by polarization curves and electrochemical impedance spectroscopy (EIS) in simulated atmosphere. The results indicated that, the corrosion resistance of the hydrostatic extruded AZ80 magnesium alloy with uneven deformed grains and increased sub-grains were obviously weakened, with larger corrosion current density in the polarization curves and lower corrosion resistances in the electrochemical impedance spectroscopy plots. This was mainly because of the hydrostatic extrusion which made AZ80 magnesium alloy within large numbers of dislocation tangles. So the residual stress increased the electrochemical activity of magnesium alloy which reduced the corrosion resistance of magnesium alloys.

Thermal Parameters Influence Assessed by Electrochemical Impedance Spectroscopy on a Ni50Ti48Nb2 Shape Memory Alloy

2018 ◽  
Vol 69 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Ioana Arina Gherghescu ◽  
Daniela Ionita ◽  
Sorin Ciuca ◽  
Ruxandra Elena Dumitrescu
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Transformation Temperatures ◽  
Electrochemical Corrosion Behavior

This paper presents some electrochemical impedance spectroscopy research results concerning the corrosion resistance of a shape memory Ni50Ti48Nb2 alloy. This one was previously studied by SEM and DSC [1,2] but some new research features had to be made clear in order to be able to explain its electrochemical corrosion behavior. The chemical composition Ni50Ti48Nb2 was chosen in order to obtain a shape memory alloy having a wider hysteresis than equiatomic NiTi, for the purpose of achieving a better thermomechanical stability. Cryogenic applications are aimed. After processing the cast ingot, two samples, S1 and S2, were further annealed at 800�C/12 h and, respectively, at 900�C/12h. Scanning electron micrographs together with the chemical elements mapping results were obtained. They were related to the previous results concerning the informations on the structure of the different phases found in this NiTiNb alloy: austenite, martensite and secondary phases, as well as some primary compounds [1,2]. Considering the size and shape of the complex precipitate particles of NiTiNb in the two differently heat treated samples, these were found responsible for some changes in the transformation temperatures [3] but the electrochemical corrosion behavior of the alloy seems to be influenced to a lesser extent by the heat treatments. Both samples exhibit good values of corrosion resistance, however S2 shows better values than S1. Thus lower transformation temperatures and a slightly better corrosion resistance make the Ni50Ti48Nb2 alloy annealed at 900�C/12h subsequently submitted to thermal cycling to be the right choice for producing couplings in the cryogenic industry.

Studies on Corrosion Behavior of S-165 and HP Supermartensitic Stainless Steels in Cl- Environment

2011 ◽  
Vol 695 ◽  
pp. 425-428
Author(s):  
Duo Wang ◽  
De Ning Zou ◽  
Chang Bin Tang ◽  
Kun Wu ◽  
Huan Liu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Polarization Curves ◽  
Chemical Compositions ◽  
Pitting Potential ◽  
Potentiodynamic Polarization Curves

Supermartensitic stainless steel grades are widely used in oil and gas industries to substitute duplex and super duplex stainless steels these years. In this paper the corrosion behavior of supermartensitic stainless steels with different chemical compositions, S-165 and HP, was investigated in Cl-environment. All the samples were treated by quenching at 1000 °C followed by tempering at 630 °C for 2h. After heat treatment, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were determined on both kinds of samples. Polarization curves shows that the metastable pitting nucleuses were formed in passive area and the Cr content is the most important factor leading to the differences of pitting potential. The potentiodynamic polarization curves were conducted at various NaCl contents (5000, 15000 and 35000 ppm) and emphasized the need to account for the Cl-sensitivity of samples under corrosion environment. The results show that, the pitting potential decrease with the increase of chloride contents. The behavior of passive film was analyzed by electrochemical impedance spectroscopy.

Corrosion Behavior of Copper in Halide Solutions

2012 ◽  
Vol 189 ◽  
pp. 36-39
Author(s):  
Hai Jiao Yang ◽  
Sheng Tao Zhang ◽  
Lei Zhang
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Theoretical Basis ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Halide Ions ◽  
Corrosive Effect ◽  
Electrochemical Corrosion Behavior

The corrosion behavior of copper in halide solutions was investigated by cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). On this basis, the mechanism of electrochemical corrosion behavior of Cu in halide solutions has been analyzed. The study explores the corrosive effect of the halide ions on copper materials and provides a theoretical basis for the inhibition of halide ions on the corrosion of copper materials.

In Vitro Evaluation of Degradation of Biodegradable Silane Based Coating on Mg-Zn-Ca Alloy in a Physiological Environment

2013 ◽  
Vol 765 ◽  
pp. 803-807
Author(s):  
Gaur Swati ◽  
Anand Sawroop Khanna ◽  
Raghuvir Kumar Singh Raman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Body Fluid ◽  
Degradation Rate ◽  
Electrochemical Impedance ◽  
Silane Coating ◽  
Corrosion Barrier

In the present study, combinations of a phosphonato silane with a precursor, Methyltriethoxy silane (MTEOS) in various ratios were applied onto the alloy Mg-6Zn-Ca. The corrosion resistance of the coated and uncoated specimens in a modified simulated body fluid (m-SBF) was characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Results suggest that the silane coating significantly decreases the degradation rate of the magnesium alloy, indicating its potential to be used as a corrosion barrier for magnesium alloy temporary implants.

Preparation and Characterization of Polylactic Acid Coating on the Surface of Magnesium Alloy

2015 ◽  
Vol 814 ◽  
pp. 132-136 ◽  
Author(s):  
Xian Yang Hua ◽  
Mei Feng He ◽  
Xiao Qin Zhou
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Corrosion Rate ◽  
Polylactic Acid ◽  
Magnesium Alloys ◽  
Electrochemical Impedance ◽  
Hank’S Solution ◽  
Acid Coating

Magnesium is one of the elements necessary for the body, is the man behind the body’s content of potassium ions within the cell are involved in a series of metabolic processes in vivo, including the formation of bone cells , acceleration of bone healing ability. Resulting from the good mechanical properties and biocompatibility, magnesium alloy is used in medical intervention material, but the high corrosion rate of magnesium alloys is the main drawback to their widespread use, especially in biomedical applications. There is a need for developing new coatings that provide simultaneously corrosion resistance and enhanced biocompatibility. In this work the medical magnesium alloy surface are dipped and coated with polylactic acid, so that obtain a dense uniform polylactic acid coating. And the corrosion resistance of the coating is studied in order to obtain controlled degradable and corrosion resisted magnesium alloy biological material. This paper mainly studies the influence of different concentrations of polylactic acid coating on AZ91D magnesium alloy corrosion resistance. The coated samples were immersed in Hank’s solution and the coating performance was studied by electrochemical impedance spectroscopy and scanning electron microscopy. This research is about the influence of the coating on the corrosion resistance of magnesium alloy through the open circuit potential, polarization curves, electrochemical impedance spectroscopy and Mott-Schottky. The results confirmed that the polylactic acid slow down the corrosion rate of AZ91D magnesium alloys in Hank’s solution. And along with the increase of poly lactic acid concentration, the corrosion resistance of magnesium alloys is improved. There is a wide variation of the corrosion morphology magnesium alloy AZ91D specimens after the surface modification using polylactic acid coating, compared with the unmodified.

Corrosion Behavior of HRB400 Reinforcing Steel Based on Electrochemical Impedance Spectroscopy

2011 ◽  
Vol 105-107 ◽  
pp. 1797-1800
Author(s):  
Yu Ye Xu ◽  
Bi Lan Lin
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Resistance Index ◽  
Chloride Ions ◽  
Reinforcing Steel ◽  
Kinetics Parameters ◽  
Transfer Resistance

Electrochemical impedance spectroscopy (EIS) technique was used to investigate the corrosion behavior of HRB400 reinforcing steel in Simulated Concrete Pore (SCP) solutions differently contaminated by bicarbonate ions and/or chloride ions. The corrosion kinetics parameters of the capacitance Y0-CPEdl, surface roughness n0-CPEdl and charge transfer resistance Rct of the electric double-layer capacitance of the interface of solution/HRB400 were analyzed and were compared to those of HPB235 reinforcing steel. The results show that the corrosion resistance index of HRB400 and HPB235 is increased with an increase in NaCl content to 0.1%, but that is decreased markedly for a larger NaCl content; and that of them is decreased largely with an increase in pH; the decrease extent of the corrosion resistance index of HRB400 with NaCl or pH is larger than that of HPB235; and the corrosion resistance of HRB400 is inferior to that of HPB235.

scholarly journals Corrosion Performance of Cu-Based Coins in Artificial Sweat

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
J. Porcayo-Calderon ◽  
R. A. Rodríguez-Díaz ◽  
E. Porcayo-Palafox ◽  
L. Martinez-Gomez
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Polarization Curves ◽  
Corrosion Mechanism ◽  
Corrosion Performance ◽  
Linear Polarization Resistance ◽  
Artificial Sweat ◽  
Anodic Zone

The performance of different Cu-based coins in artificial sweat was evaluated. The electrochemical behavior of the coins was determined by potentiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy. Regardless of the chemical composition of the Cu-based coins, they showed similar polarization curves; particularly, the observed similarity in the anodic zone suggests that the corrosion mechanism is the same in all cases. The presence of Ni and Zn does not appreciably affect the corrosion resistance of Cu. However, the presence of both elements affects the corrosion resistance of Cu. Electrochemical impedance spectroscopy measurements showed the presence of three time constants with very similar characteristics, again indicating that the main corrosion mechanism is the same in all cases. Equivalent circuits confirmed that the corrosion performance of the Ni-Zn-Cu coins depends on the Zn/Ni ratio, such that decreasing this value decreases the corrosion resistance of the alloy. In general, nickel has a detrimental effect due to the formation of highly soluble Ni-based corrosion products.

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