scholarly journals Effect of Microstructure on Near-Neutral-pH SCC

2000 ◽  
Author(s):  
Jeffrey Bulger ◽  
Jingli Luo
Keyword(s):  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Slow Strain Rate Test ◽  
Corrosion Properties ◽  
The Third ◽  
Neutral Ph ◽  
Rate Test ◽  
Resistance Tests ◽  
Effect Of Microstructure

Three components are required for stress corrosion cracking: stress, an environment and a susceptible alloy. The environment that causes near-neutral-pH SCC has been established as a dilute bicarbonate environment and the effect of stress on this type of SCC has received a considerable amount of research; however, the third component, the susceptible alloy, has received little research. The effect of microstructure on near-neutral-pH SCC was investigated using the slow strain rate test. The effect of the microstructure on the corrosion properties is also investigated using polarization resistance tests, potentiodynamic scans and electrochemical impedance spectroscopy. The results indicate that the microstructure influences both the SCC and corrosion behaviour.

scholarly journals Tribological and Corrosion Properties of Iron-Based Alloys

2015 ◽  
Author(s):  
E. Vernickaite ◽  
Z. Z. Antar ◽  
A. Nicolenco ◽  
R. Kreivaitis ◽  
N. Tsyntsaru ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Steel Substrate ◽  
Alloy Coating ◽  
Scratch Test ◽  
Advanced Materials ◽  
Industrial Accidents ◽  
Corrosion Properties ◽  
X Ray ◽  
Wear And Corrosion Resistance

Corrosion is responsible for industrial maintenance and industrial accidents costs. A helpful way to prevent corrosion is to develop advanced materials with highly anti-corrosive properties. The electrodeposition is one of the most attractive methods for obtaining these materials. This work deals with evaluation of the tribological and corrosion behaviour of electrodeposited Fe-W and Fe-W-P alloys. Electrodeposits were obtained from 4 different baths and were characterized by means of scanning electron microscopy; X-ray dispersive energy spectroscopy; X-ray diffraction spectroscopy. The hardness was determined by Micro-indentation carried out at normal forces varying from 98 mN up to 980 mN with a loading rate of 1961 mN/min. A ball-disc tribometer was used to study the tribological properties at 90 °C. A diamond indenter, having a radius of 100 µm, was used to carry the scratch test. Corrosion behaviour was studied using polarization and electrochemical impedance spectroscopy technique. It was investigated that in all cases Fe-W and Fe-W-P alloy coatings exhibit greater micro-hardness than the stainless steel substrate. The amorphous-like ternary Fe-W-P alloy coatings demonstrate higher wear and corrosion resistance and lower friction coefficient compared to binary Fe-W alloy coating.

scholarly journals The influence of deformation on the corrosion properties of the material

2017 ◽  
Vol 61 (3) ◽  
pp. 86-90 ◽  
Author(s):  
M. Nováková ◽  
O. Chocholatý ◽  
A. Kříž
Keyword(s):  
Corrosion Rate ◽  
Tensile Stress ◽  
Electric Current ◽  
Polarization Resistance ◽  
Corrosion Potential ◽  
Corrosion Behaviour ◽  
Corrosion Properties ◽  
Titanium Grade ◽  
Changes Over Time ◽  
Over Time

Abstract This work was focused on changes of corrosion behaviour influence of deformation. The This work focuses on changes in corrosion behaviour under the influence of deformation. The main purpose is to observe the changes caused by tensile stress. The experimental material used is steel 1.4301 and titanium GRADE 2. The measurements were carried out using a potentiostat, which measures potential changes over time and electric current. The electrolyte used was 3.5% NaCl. Corrosion properties, especially polarization resistance, corrosion potential and corrosion rate, were evaluated from the measurements. The results demonstrate the changing corrosion properties depending on deformation. The corrosion properties worsened as the deformation increased.

scholarly journals Corrosion Study of Pipeline Steel under Stress at Different Cathodic Potentials by EIS

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1353 ◽  
Author(s):  
Ricardo Galván-Martínez ◽  
Ricardo Orozco-Cruz ◽  
Andrés Carmona-Hernández ◽  
Edgar Mejía-Sánchez ◽  
Miguel A. Morales-Cabrera ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Anodic Dissolution ◽  
Active Sites ◽  
Hydrogen Diffusion ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Metallic Surface ◽  
Slow Strain Rate Test ◽  
Rate Test ◽  
Fracture Surface Analysis

The effect of different cathodic potentials applied to the X70 pipeline steel immersed in acidified and aerated synthetic soil solution under stress using a slow strain rate test (SSRT) and electrochemical impedance spectroscopy (EIS) was studied. According to SSRT results and the fracture surface analysis by scanning electron microscopy (SEM), the steel susceptibility to stress corrosion cracking (SCC) increased as the cathodic polarization increased (Ecp). This behavior is attributed to the anodic dissolution at the tip of the crack and the increment of the cathodic reaction (hydrogen evolution) producing hydrogen embrittlement. Nevertheless, when the Ecp was subjected to the maximum cathodic potential applied (−970 mV), the susceptibility decreased; this behavior is attributed to the fact that the anodic dissolution was suppressed and the process of the SCC was dominated only by hydrogen embrittlement (HE). The EIS results showed that the cathodic process was influenced by the mass transport (hydrogen diffusion) due to the steel undergoing so many changes in the metallic surface as a result of the applied strain that it generated active sites at the surface.

scholarly journals Electroless Deposition of Ni-Cu-P Coatings Containing Nano-Al2O3Particles and Study of Its Corrosion Protective Behaviour in 0.5 M H2SO4

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
H. Ashassi-Sorkhabi ◽  
H. Aminikia ◽  
R. Bagheri
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Composite Coatings ◽  
Electrochemical Methods ◽  
Sem Images ◽  
Corrosion Properties ◽  
Plating Bath ◽  
Nanoparticles Concentration ◽  
Good Agreement

Ni-Cu-P/nano-Al2O3composite coatings are prepared on mild steel from an alkaline electroless plating bath containing different concentrations of Al2O3nanoparticles. The protective effect of codeposited nanoparticles on the corrosion behaviour of the coatings is studied in 0.5 M H2SO4solution. The electrochemical methods, that is, electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization measurements, are used to characterize the corrosion properties of the coatings. The results show that the inclusion of nanosized particles leads to significant improvement of corrosion resistance of the coatings. The highest corrosion resistance is obtained at 20 ppm of nanoparticles concentration in the plating bath. The ECN measurements results are in good agreement with results obtained from two other electrochemical methods after trend removal. The SEM images prove that nano-Al2O3particles were embedded in the Ni-Cu-P matrix and are dispersed uniformly on the coating surface.

Corrosion Behaviour of Automotive Steel Sheets Depending on the Degree of Deformation

2014 ◽  
Vol 635 ◽  
pp. 57-60 ◽  
Author(s):  
Janette Brezinová ◽  
Juraj Koncz ◽  
Miroslav Tomáš ◽  
Ján Slota
Keyword(s):  
Corrosion Rate ◽  
Steel Sheet ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Experimental Studies ◽  
Corrosion Monitoring ◽  
Corrosion Properties ◽  
Degree Of Deformation ◽  
Steel Sheets ◽  
Automotive Steel

This paper presents the results of research aimed to measuring the corrosion properties of automotive steel sheets. The degree of deformation influence to the corrosion properties of the steel sheet for car body parts has been proven by the modern methods of corrosion monitoring such as Electrochemical Impedance Spectroscopy. Corrosion rate was assessed using electrochemical methods in 0.1 M solution of NaCl. Experimental studies have pointed out if degree of deformation increases the corrosion rate of the steel sheet increases as well.

scholarly journals Influence of Potential Scan Rate on Corrosion Behaviour of Heat Treated AA 7075 Alloy in Sulphuric Acid Solution

2018 ◽  
Vol 15 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Neeraj Kumar ◽  
Manoranjan Kumar Manoj ◽  
M. Kalyan Phani
Keyword(s):  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Electrochemical Behaviour ◽  
Sulphuric Acid Solution ◽  
Corrosion Property ◽  
Corrosion Properties ◽  
Scan Rate ◽  
Charging Current ◽  
7075 Alloy

In this paper, the effect of scan rate on the corrosion parameters and electrochemical behaviour of Retrogression and Re-aging (RRA) heat treatment of 7075 aluminium alloy has been investigated by Potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) methods. The Potentiodynamic polarization (PD) curves were obtained at various scan rates for aged aluminium alloys in 0.5 M H2SO4 solution. The results show that at high scan rates shows unpredicted fluctuation of charging current, whereas at lower scan rates fewer disturbances are observed. The aged samples were chemically and mechanically characterized. It was observed that the RRA at 0.7 h shown improved corrosion property as well as mechanical properties compared to T6 temper. The corrosion properties were confirmed by EIS and polarization experiments.

Influence of copper addition on corrosion properties and hardness of Al–Cu/Al two-layered-structure composites

2021 ◽  
pp. 095440622110342
Author(s):  
Kotikala Rajasekhar ◽  
V Suresh Babu ◽  
MJ Davidson ◽  
G Raghavendra
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Chi Square ◽  
Corrosion Properties ◽  
Cu Content ◽  
Copper Addition ◽  
Best Fit ◽  
Layered Samples

An experimental investigation has been observed on hardness, sintered density and corrosion behaviour of two-layered structured Al-xCu/Al sample through powder metallurgical route under hot compaction condition. The samples were prepared with different percentages of Cu content (x: 5 wt. %, 10 wt. % and 15 wt. %) in the aluminium matrix with a constant pressure of 400 MPa with different hot-pressed temperatures (500 °C, 550 °C and 600 °C) at a dwelling time of 3 h. The developed two-layered samples microstructure was analysed using the optical and scanning electron microscope. The highest value of micro-hardness (100.6 HV) was obtained at interface region of 15% of copper at 550 °C. The corrosion rate of Al-Cu/Al two-layered samples at the interface were analyzed through the potentiodynamic polarization test and found that with addition of copper content the susceptibility of corrosion increases. The Electrochemical Impedance Spectroscopy (EIS) test was conducted to know the equivalent circuit model, which provides a minimum chi-square value and that circuit model taken as best-fit circuit model. From the EIS results, it was found that 10 wt. %Cu sample circuit provides minimum chi-square value.

Electrochemical Impedance Characteristics of Sintered 7075 Aluminum Alloy Under Ssrt Condition

2013 ◽  
Vol 58 (2) ◽  
pp. 505-508 ◽  
Author(s):  
S. Sunada ◽  
N. Nunomura
Keyword(s):  
Aluminum Alloys ◽  
Complex Shape ◽  
Electrochemical Impedance ◽  
Ingot Metallurgy ◽  
View Point ◽  
Corrosion Properties ◽  
Electrochemical Tests ◽  
Impedance Characteristics ◽  
Polarization Test ◽  
Conventional Ingot

Powder metallurgy (P/M) process has the advantage of better formability to fabricate complex shape products without machining and welding. And recently this P/M process has been applied to the production of aluminum alloys. The P/M aluminum alloys thus produced also have received considerable interest because of their fine and homogeneous structure. Many papers have been published on the mechanical properties of the aluminum alloys produced by P/M process while there have been few on their corrosion properties from the view point of electrochemistry. In this experiment, therefore, two kinds of 7075 aluminum alloys prepared by the conventional ingot metallurgy (I/M) process and P/M process were used, I/M material is commercially available. and their corrosion behavior were investigated through the electrochemical tests such as potentiodynamic polarization test, slow rate strain tensile (SSRT) test and electrochemical impedance spectroscopy (EIS) measurement under SSRT test in the corrosion solution and the deionized water.

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

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