scholarly journals Corrosion Behavior of As-Cast Binary Mg-Dy Alloys

2011 ◽  
Vol 690 ◽  
pp. 417-421 ◽  
Author(s):  
Lei Yang ◽  
Frank Feyerabend ◽  
Karl Ulrich Kainer ◽  
Regine Willumeit ◽  
Norbert Hort
Keyword(s):  
Corrosion Rate ◽  
Optical Microscope ◽  
Direct Chill ◽  
Second Phase ◽  
Alloying Element ◽  
High Solubility ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Filiform Corrosion ◽  
Very High

The addition of rare earth elements (REE) is an effective way to improve the corrosion properties of magnesium alloys. Dysprosium has a very high solubility in Mg (25.3 wt.% at 561 °C) and could therefore be a promising alloying element for Mg based implants. In this study, four binary Mg-xDy (x=5, 10, 15 and 20 in wt.%) alloys were prepared by permanent mould direct chill casting. Microstructure and Dy distribution were investigated using optical microscope and EDX analysis. Corrosion rate was measured with hydrogen evolution method and corrosion morphology was observed after immersion for different time in 0.9 wt% NaCl solution with optical and SEM. The results show that with the increase of Dy, the amount of Dy in Mg matrix and area of Dy segregation are both increased. At the same time, the amount of second phase is also increased. Filiform corrosion is reduced while pitting corrosion is increased with the increment of Dy. As a result, lowest corrosion rate is obtained at Mg-10Dy alloy.

Influence of various sterilization methods on hardness, grain size and corrosion rate of a Mg6Ag-alloy

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Frank Feyerabend ◽  
Martin Johannisson ◽  
Zhidan Liu ◽  
Regine Willumeit-Römer
Keyword(s):  
Grain Size ◽  
Corrosion Rate ◽  
Optimum Ratio ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Materials Properties ◽  
Physiological Conditions ◽  
Alloying System ◽  
Dry Heat

AbstractSterilization is a necessary step for all implant materials. Different methods can influence the materials properties. Especially important for magnesium as degradable materials is the determination of the corrosion properties. In this study the influence of 70% ethanol, glutaraldehyde, autoclaving, dry heat, UV-, gamma- and electron beam-irradiation on mechanical and corrosion parameters were analyzed. As mechanical parameters hardness and grain size were determined. The corrosion rate under physiological conditions, weight of the corrosion layer and corrosion morphology was determined. It could be demonstrated that irradiation treatments and 70% ethanol are suitable methods, as they decrease the corrosion rate. Heat-introducing methods (autoclaving and dry heat) acted as incomplete ageing treatments on this alloy and therefore increased the corrosion rate. Furthermore, osmolality showed a better correlation to the actual corrosion rate than the pH. Therefore an optimum ratio between alloying system, implant and sterilization method has to be established, depending on the intended application.

Effects of Surface Oxide Coating on Corrosion Behavior of Ti-1023/LY12 Galvanic Couple

2013 ◽  
Vol 668 ◽  
pp. 880-884 ◽  
Author(s):  
Jun Xiu Shi ◽  
Jian Hua Liu
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Oxide Coating ◽  
Optical Microscope ◽  
Open Circuit ◽  
Localized Corrosion ◽  
Corrosion Attack ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Galvanic Couple

Galvanic corrosion behavior of Ti-1023 titanium alloy coupled to LY12 aluminum alloy was investigated in 3.5% NaCl solution. Particular attention was given to the effect of anodized coatings on corrosion behaviors of Ti-1023/LY12 galvanic couple. Galvanic test was conducted on the following couples: Ti-1023/LY12, Ti-1023/anodized LY12 and anodized Ti-1023/anodized LY12, respectively. Corrosion properties including open circuit potential (Eoc) of each material, galvanic corrosion potential (Eg) and galvanic corrosion current (Ig) of the couples were monitored. Corrosion morphology was observed by optical microscope (OM) and corrosion mechanisms were analyzed and discussed. It was showed that anodized coatings significantly decreased Eg and Īg of the couples and provide effective protection of the anode from suffering corrosion attack. Only slight localized corrosion was detected on anodized LY12 alloy in the two anodized couples and the LY12 in anodized Ti-1023/anodized LY12 couple was found to be least susceptible to galvanic corrosion. The LY12 alloy in the bare couple: Ti-1023/LY12, was found to be highly susceptible to galvanic corrosion and suffered severe uniform and localized corrosion attack

Effects of Heat Treatments on Corrosion Behavior of Mg AT72 Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 230-237 ◽  
Author(s):  
Zhi Qin Wang ◽  
De Jiang Li ◽  
Xiao Qin Zeng ◽  
Xiao Mei Wu ◽  
Wen Jiang Ding
Keyword(s):  
Heat Treatment ◽  
Hydrogen Evolution ◽  
High Vacuum ◽  
Treatment Method ◽  
Optical Microscope ◽  
Heat Treatments ◽  
Open Circuit ◽  
Second Phase ◽  
Corrosion Properties ◽  
Phase Phase

The effects of heat treatments, including T4, T5, T6 treatments, on corrosion behaviors of Mg-7Al-2Sn (AT72) alloy processed by high vacuum die casting have been investigated. The optical microscope, scanning electron microscope observations were used to analyze the microstructures, especially the distribution of second phase, phase contents and grain size. The hydrogen evolution tests, electrochemical methods including open circuit potential curves and polarization curves were used to describe the corrosion properties as well. The results indicated that different heat treatments had influence on microstructures, especially distribution of second phase, phase contents and grain sizes. The existence of second phase had a relationship with corrosion properties, in which the as-cast samples showed low corrosion rate in hydrogen evolution tests while the heat treatment methods had little impact on improving corrosion resistance. The electrochemical analyses also agreed with this observation. Based on these results, the optimized heat treatment method for corrosion resistant AT72 magnesium alloy has been established.

scholarly journals Effect of Sn and Mo on Microstructure and Electrochemical Property of TiZrTaNb High Entropy Alloys

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1527
Author(s):  
Qiaoyu Li ◽  
Tengfei Ma ◽  
Yuliang Jin ◽  
Xiaohong Wang ◽  
Duo Dong ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
Alloying Elements ◽  
High Entropy Alloy ◽  
Corrosion Mechanism ◽  
High Entropy Alloys ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
High Entropy

The effects of Sn and Mo alloying elements on the microstructure and electrochemical properties of TiZrTaNb high entropy alloys were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemistry. TiZrTaNb, TiZrTaNbMo and TiZrTaNbSn alloys with equal atomic ratio were prepared by the arc melting method. The results showed that the microstructure of the high entropy alloys was dendritic structure with single BCC structure. The addition of Mo and Sn elements promoted the growth of the dendritic structure and accelerated the interdendritic segregation of the TiZrTaNb alloy. The TiZrTaNbMo alloy exhibited excellent corrosion properties compared to TiZrTaNb and TiZrTaNbSn alloys based on corrosion parameters Icorr, φcorr, Ipass. The corrosion mechanism is discussed based on the corrosion morphology. The alloying elements have an important effect on the microstructure and electrochemical properties of a high entropy alloy.

Effects of Ti-1023 Anodized Coating on Corrosion Behavior of Ti-1023/30CrMnSiA and Ti-1023/LY12 Galvanic Couples

2007 ◽  
Vol 546-549 ◽  
pp. 1821-1826
Author(s):  
Jian Hua Liu ◽  
Jun Xiu Shi ◽  
Song Mei Li ◽  
Jun Lan Yi
Keyword(s):  
Corrosion Potential ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Open Circuit ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Average Value ◽  
Galvanic Couples ◽  
Corrosion Mechanisms

Galvanic properties were evaluated on bare and anodized Ti-1023 titanium alloy which coupled to Ni-electroplated, Zn-electroplated, Cd-electroplated 30CrMnSiA and anodized LY12, respectively. Corrosion properties including open circuit potential (Eoc) of each material, galvanic corrosion potential (Eg), and corrosion current (Ig) of the couples were monitored in conjunction with a Model 263A potentiostat system. Corrosion current density (Īg) and average value of corrosion potential (Ēg) were calculated from Ig-time and Eg-time curves, respectively. Corrosion morphology was observed on a optical microscope (OM) and corrosion mechanisms were analyzed and discussed. The corrosion resistance of Ti-1023/LY12 couple was significantly improved by Ti-1023 anodized coating. However, the coating accelerated the dissolve of the three electroplated coatings in the other galvanic couples, resulting in a heavy corrosion attack on 30CrMnSiA steel.

Study on Corrosion Properties of Medical Mg-Zn Alloy

2018 ◽  
Vol 777 ◽  
pp. 607-611
Author(s):  
Zhi Ling Wang
Keyword(s):  
Simulated Body Fluid ◽  
Corrosion Rate ◽  
Body Fluid ◽  
Body Fluids ◽  
Corrosion Products ◽  
Corrosion Properties ◽  
Corrosion Morphology ◽  
Zn Content ◽  
Simulated Body Fluids ◽  
Zn Alloy

Casting Mg-Zn alloy was corroded on the surface and analyzed the corrosion morphology and corrosion properties under different corrosion conditions. The results show that Mg-Zn alloy is unevenly by corrosion in simulated body fluids and the corrosion products are brittle and easy to break. With the increase of Zn content in Mg-Zn alloy, the corrosion rate of casting Mg-Zn alloy in simulated body fluid is improved obviously.

COOPER ALLOY 22W

Alloy Digest ◽  
1963 ◽  
Vol 12 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Creep Rate ◽  
Corrosion Rate ◽  
Physical Properties ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Hot Gas ◽  
Gas Corrosion ◽  
Very High

Abstract Cooper Alloy 22W is a high strength, heat resistant casting alloy with a low creep rate. It is recommended for heat applications where stress and hot gas corrosion rate are very high. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: SS-146. Producer or source: Cooper Alloy Corporation.

scholarly journals Microstructures and Macrosegregation of Al–Zn–Mg–Cu Alloy Billet Prepared by Uniform Direct Chill Casting

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 708
Author(s):  
Li Zhou ◽  
Yajun Luo ◽  
Zhenlin Zhang ◽  
Min He ◽  
Yinao Xu ◽  
...  
Keyword(s):  
Mold Wall ◽  
Direct Chill ◽  
Element Distribution ◽  
Direct Chill Casting ◽  
Electromagnetic Stirring ◽  
Alloying Elements ◽  
Alloying Element ◽  
Casting Method ◽  
Chill Casting ◽  
Cu Alloy

In this study, large-sized Al–Zn–Mg–Cu alloy billets were prepared by direct chill casting imposed with annular electromagnetic stirring and intercooling; a process named uniform direct chill casting. The effects of uniform direct chill casting on grain size and the alloying element distribution of the billets were investigated and compared with those of the normal direct chill casting method. The results show that the microstructures were refined and the homogeneity of the alloying elements distribution was greatly improved by imposing the annular electromagnetic stirring and intercooling. In uniform direct chill casting, explosive nucleation can be triggered, originating from the mold wall and dendrite fragments for grain refinement. The effects of electromagnetic stirring on macrosegregation are discussed with consideration of the centrifugal force that drives the movement of melt from the central part towards the upper-periphery part, which could suppress the macrosegregation of alloying elements. The refined grain can reduce the permeability of the melt in the mushy zone that can restrain macrosegregation.

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.

scholarly journals Corrosion Behavior of LENS Deposited CoCrMo Alloy Using Bayesian Regularization-Based Artificial Neural Network (BRANN)

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Nagoor Basha Shaik ◽  
Kedar Mallik Mantrala ◽  
Balaji Bakthavatchalam ◽  
Qandeel Fatima Gillani ◽  
M. Faisal Rehman ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Corrosion Rate ◽  
Prediction Models ◽  
Test Time ◽  
Bayesian Regularization ◽  
Cobalt Chromium ◽  
Corrosion Properties ◽  
Cocrmo Alloy ◽  
Artificial Neural

AbstractThe well-known fact of metallurgy is that the lifetime of a metal structure depends on the material's corrosion rate. Therefore, applying an appropriate prediction of corrosion process for the manufactured metals or alloys trigger an extended life of the product. At present, the current prediction models for additive manufactured alloys are either complicated or built on a restricted basis towards corrosion depletion. This paper presents a novel approach to estimate the corrosion rate and corrosion potential prediction by considering significant major parameters such as solution time, aging time, aging temperature, and corrosion test time. The Laser Engineered Net Shaping (LENS), which is an additive manufacturing process used in the manufacturing of health care equipment, was investigated in the present research. All the accumulated information used to manufacture the LENS-based Cobalt-Chromium-Molybdenum (CoCrMo) alloy was considered from previous literature. They enabled to create a robust Bayesian Regularization (BR)-based Artificial Neural Network (ANN) in order to predict with accuracy the material best corrosion properties. The achieved data were validated by investigating its experimental behavior. It was found a very good agreement between the predicted values generated with the BRANN model and experimental values. The robustness of the proposed approach allows to implement the manufactured materials successfully in the biomedical implants.

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