scholarly journals Effect of Recrystallization Annealing on Corrosion Behavior of Ta-4%W Alloy

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 117 ◽  
Author(s):  
Guoqiang Ma ◽  
Qiongyao He ◽  
Xuan Luo ◽  
Guilin Wu ◽  
Qiang Chen
Keyword(s):  
Corrosion Resistance ◽  
Anodic Dissolution ◽  
Corrosion Behavior ◽  
Current Density ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Recrystallization Annealing ◽  
Site Lattice

The effect of recrystallization annealing on corrosion behavior of Ta-4%W alloy was studied. It is found that the deformed sample contains high dense dislocations and dislocation boundaries. During annealing, these dislocations and dislocation boundaries are replaced by recrystallizing grains until the alloy is fully recrystallized. Both the anodic dissolution and the cathodic activity is much more blocked. The corrosion potential gradual shift towards negative values and corrosion current density decrease, while polarization resistance increases after annealing, indicating enhanced corrosion resistance of the alloy. Such an enhancement is caused by the increase of low-Σ coincide site lattice boundaries and decrease of dislocations and dislocation boundaries.

scholarly journals An electrochemical method to investigate the effects of compound composition on gold dissolution in thiosulfate solution

2020 ◽  
Vol 9 (1) ◽  
pp. 496-502 ◽  
Author(s):  
Zhaohui Zhang ◽  
Bailong Liu ◽  
Mei Wu ◽  
Longxin Sun
Keyword(s):  
Dissolution Rate ◽  
Current Density ◽  
Polarization Resistance ◽  
Electrochemical Method ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Gold Dissolution ◽  
Tafel Polarization ◽  
Edta Solution

AbstractThe electrochemical behavior of gold dissolution in the Cu2+–NH3–S2O32−–EDTA solution has been investigated in detail by deriving and analyzing the Tafel polarization curve, as this method is currently widely implemented for the electrode corrosion analysis. The dissolution rate of gold in Cu2+–NH3–S2O32−–EDTA solution was determined based on the Tafel polarization curves, and the effects of various compound compositions in a Cu2+–NH3–S2O32−–EDTA mixture on the corrosion potential and corrosion current density were analyzed. The results showed that the corrosion potential and polarization resistance decreased, whereas the corrosion current density increased for certain concentrations of S2O32−–NH3–Cu2+ and EDTA, indicating that the dissolution rate of gold had changed. The reason for promoting the dissolution of gold is also discussed.

scholarly journals Corrosion Behavior and Osteogenic Activity of a Biodegradable Orthopedic Implant Mg–Si Alloy with a Gradient Structure

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 781
Author(s):  
Weiyan Jiang ◽  
Wenzhou Yu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Gradient Structure ◽  
Orthopedic Implant ◽  
Biological Functions ◽  
Alloy Matrix ◽  
Osteogenic Activity

A gradient Mg-8 wt % Si alloy, which was composed of the agglomerated Mg2Si crystals coating (GMS8-1) and the eutectic Mg–Si alloy matrix (GMS8-2), was designed for biodegradable orthopedic implant materials. The bio-corrosion behavior was evaluated by the electrochemical measurements and the immersion tests. The results show that a significant improvement of bio-corrosion resistance was achieved by using the gradient Mg–Si alloy, as compared with the traditional Mg-8 wt % Si alloy (MS8), which should be attributed to the compact and insoluble Mg2Si phase distributed on the surface of the material. Especially, GMS8-1 exhibits the highest polarization resistance of 1610 Ω, the lowest corrosion current density of 1.7 × 10−6 A.cm−2, and the slowest corrosion rate of 0.10 mm/year. In addition, GMS8-1 and GMS8-2 show better osteogenic activity than MS8, with no cytotoxicity to MC3T3-E1 cells. This work provides a new way to design a gradient biodegradable Mg alloys with some certain biological functions.

Electrochemical Characteristics of Lanthanum Hexaboride in the Environments Containing S2-

2010 ◽  
Vol 663-665 ◽  
pp. 473-476
Author(s):  
Shu Qi Zheng ◽  
Chang Feng Chen ◽  
Rui Jing Jiang ◽  
Dan Ni Wang
Keyword(s):  
Partial Pressure ◽  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Lanthanum Hexaboride ◽  
Electrochemical Characteristics

In the environment with H2S/CO2 or Na2S, the corrosion behavior of Lanthanum hexaboride (LaB6) was investigated by electrochemistry methods. The results indicated that the corrosion potential (Ecorr) and Rf of LaB6 increased as the partial pressure of H2S increased, while the corrosion current density (Icorr) decreased. In the environment containing Na2S, as the content of Na2S increased, the corrosion potential (Ecorr) and Rf of LaB6 decreased, while the corrosion current density (Icorr) increased. Thus, the addition of H2S into the environment with H2S/CO2 would inhibit the corrosion of LaB6; while in the environment containing Na2S, the increasing of the content of Na2S would accelerate the corrosion of LaB6.

Corrosion Resistance of Mg-4Zn Alloy with Amorphous Micro-Arc Oxidation Coating in Simulated Body Fluid

2016 ◽  
Vol 852 ◽  
pp. 1325-1333
Author(s):  
Li Chen Zhao ◽  
Shuang Jin Liu ◽  
Yu Min Qi ◽  
Chun Xiang Cui
Keyword(s):  
Corrosion Resistance ◽  
Simulated Body Fluid ◽  
Current Density ◽  
Polarization Resistance ◽  
Body Fluid ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Metal Substrate ◽  
Electrochemical Measurements ◽  
Micro Arc Oxidation

A binary Mg-4Zn alloy was fabricated as a potential degradable biomaterial. To improve the corrosion resistance of Mg-4Zn alloy, an amorphous micro-arc oxidation (MAO) coating was prepared on the Mg-4Zn substrate. Electrochemical measurements and immersion tests were employed to evaluate the corrosion resistance of the specimen in simulated body fluid (SBF). Electrochemical measurements show that the Mg-4Zn alloy covered with a MAO coating has a much lower corrosion current density and a much greater polarization resistance. Immersion tests suggest that the degradation of Mg-4Zn substrate is relatively serious during the initial 8 h of immersion although it has been protected by a MAO coating. When most micro-pores within the MAO coating have been filled with precipitates resulted from the corrosion of the metal substrate, the degradation of the Mg-4Zn substrate is significantly delayed.

Corrosion behavior of X80 steel under disbond coating interfered with AC

2019 ◽  
Vol 66 (6) ◽  
pp. 704-718
Author(s):  
Qingmiao Ding ◽  
Zili Li ◽  
Tao Shen ◽  
Gan Cui
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
The Self ◽  
Stray Current ◽  
Content Type ◽  
X80 Steel ◽  
Protection Potential

Purpose This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method. Design/methodology/approach The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference. Findings The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased. Originality/value This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

scholarly journals Experimental Study on the Influence of Sulfate Reducing Bacteria on the Metallic Corrosion Behavior under Disbonded Coating

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Qingmiao Ding ◽  
Liping Fang ◽  
Yanyu Cui ◽  
Yujun Wang
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Test Point ◽  
Sulfate Reducing ◽  
Metallic Corrosion ◽  
Reducing Bacteria ◽  
Disbonded Coating

A rectangle disbonded coating simulation device was used to research the effect of sulfate reducing bacteria (SRB) on the metallic corrosion behavior under disbonded coating by the electrochemical method. The results showed that the metal self-corrosion potential at the same test point had little change in the initial experiment stage, whether the solution was without or with SRB. The potential amplitude in the solution with SRB was larger than that without SRB in the later corrosion period. The corrosion current density of the metal at the same test point increased gradually over time in the solution with or without SRB, and SRB could accelerate the corrosion of the metal in the disbonded crevice. The metal self-corrosion potential in the crevice had little change in the SRB solution environment after adding the fungicide, but the corrosion current density decreased significantly. That meant the growth and reproduction of SRB were inhibited after adding the fungicide, so the metal corrosion rate slowed down. Among the three kinds of solution environment, increasing the coating disbonded thickness could accelerate the corrosion of the metal in the crevice, and it was the largest in the solution with SRB.

scholarly journals Corrosion Behavior of Diffusion Bonding Joints of (OFHC) Copper with Stainless Steel 304L in 3.5% NaCl

2018 ◽  
Vol 21 (1) ◽  
pp. 74
Author(s):  
Sami Abualnoun Ajeel ◽  
Ahmed Ali Akbar Akbar ◽  
Safaa Mohammed Hassoni
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Current Density ◽  
Diffusion Bonding ◽  
Corrosion Current Density ◽  
Pure Copper ◽  
Corrosion Current ◽  
Stainless Steel 304L ◽  
Materials Used

The present work deals with direct diffusion bonding welding without interlayer of austenitic stainless steel type AISI 304L with Oxygen Free High Conductivity pure copper (OFHC) in vacuum atmosphere (1.5 *10-5 mbr.). The optimum bonding conditions are temperature of 650 ◦C, duration time of 45 min. and the applied stress of 30 MPa, in order to secure a tight contact between the mating surfaces. The corrosion behavior of diffusion bonding joints in 3.5% Nacl is studied to evaluate the corrosion resistance of welding joints by using Potentiodynamic method. The observed microstructure of corroded specimen of optimum diffusion bonding joint shows that the corrosion current density has low value as compared with base materials used. During polarization, galvanic coupling is observed between two materials used. At passivity region, inverse polarity is occurred at 450mV. Therefore, passive stainless steel 304 L behaves as cathode respective to pure copper, the corrosion behavior of the diffusion bonding joint was mostly by copper side. The corrosion results indicate the presence of galvanic effect. The corrosion current density of copper, stainless steel 304L and bond joints condition were (3.66 µA/cm2, 1.62 µA/cm2 and 1.85µA/cm2) respectively. A SEM examination of corroded diffusion bonding joint indicates that the galvanic corrosion happened on copper side. The corrosion rate of bonding joint conditions was 0.85 mpy, which is less than 1%. This means that corrosion resistance of bond joint is more than excellent.

A Study on the Electroless Ni–P Deposition of AM60B Magnesium Alloy without HF in Bath

2014 ◽  
Vol 633-634 ◽  
pp. 879-882 ◽  
Author(s):  
Jing Dong Qiu ◽  
Su Qiu Jia
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Dense Structure ◽  
Electroless Ni

Based on the traditional direct electroless nickel methods, chemical baths are improved by removing HF. Examinations have been carried out on the Ni-P deposited on the interlayer for morphology, composition and corrosion-resistance by SEM, EDS, XRD and other instruments. A Ni-P film with fine and dense structure was obtained on the AM60B magnesium alloy. It exhibits lower corrosion current density and more positive corrosion potential than the substrate.

scholarly journals Structure, Corrosion Resistance, Mechanical and Tribological Properties of ZrB2 and Zr-B-N Coatings

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1194
Author(s):  
Philipp Kiryukhantsev-Korneev ◽  
Alina Sytchenko ◽  
Yuriy Kaplanskii ◽  
Alexander Sheveyko ◽  
Stepan Vorotilo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Tribological Properties ◽  
Current Density ◽  
Corrosion Current Density ◽  
Elastic Recovery ◽  
Optical Emission ◽  
Corrosion Current ◽  
Impact Testing ◽  
Total Oxidation ◽  
Mechanical And Tribological Properties

The coatings ZrB2 and Zr-B-N were deposited by magnetron sputtering of ZrB2 target in Ar and Ar–15%N2 atmospheres. The structure and properties of the coatings were investigated via scanning and transmission electron microscopy, energy dispersion analysis, optical profilometry, glowing discharge optical emission spectroscopy and X-ray diffraction analysis. Mechanical and tribological properties of the coatings were investigated using nanoindentation, “pin-on-disc” tribological testing and “ball-on-plate” impact testing. Free corrosion potential and corrosion current density were measured by electrochemical testing in 1N H2SO4 and 3.5%NaCl solutions. The oxidation resistance of the coatings was investigated in the 600–800 °С temperature interval. The coatings deposited in Ar contained 4–11 nm grains of the h-ZrB2 phase along with free boron. Nitrogen-containing coatings consisted of finer crystals (1–4 nm) of h-ZrB2, separated by interlayers of amorphous a-BN. Both types of coatings featured hardness of 22–23 GPa; however, the introduction of nitrogen decreased the coating’s elastic modulus from 342 to 266 GPa and increased the elastic recovery from 62 to 72%, which enhanced the wear resistance of the coatings. N-doped coatings demonstrated a relatively low friction coefficient of 0.4 and a specific wear rate of ~1.3 × 10−6 mm3N−1m−1. Electrochemical investigations revealed that the introduction of nitrogen into the coatings resulted in the decrease of corrosion current density in 3.5% NaCl and 1N H2SO4 solution up to 3.5 and 5 times, correspondingly. The superior corrosion resistance of Zr-В-N coatings was related to the finer grains size and increased volume of the BN phase. The samples ZrB2 and Zr-B-N resisted oxidation at 600 °C. N-free coatings resisted oxidation (up to 800 °С) and the diffusion of metallic elements from the substrate better. In contrast, Zr-B-N coatings experienced total oxidation and formed loose oxide layers, which could be easily removed from the substrate.

scholarly journals Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Zhonglu Cao ◽  
Makoto Hibino ◽  
Hiroki Goda
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Polarization Resistance ◽  
Cement Mortar ◽  
Corrosion Current ◽  
Potential Difference ◽  
Reinforcing Steel ◽  
Macrocell Current ◽  
The Relationship ◽  
Macrocell Corrosion

The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

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