Pitting Corrosion Behaviour of Boron Added Modified 9Cr–1Mo Steel: Combined Effects of Alkali and Chloride Ions

2014 ◽  
Vol 68 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Namrata Upadhyay ◽  
M. G. Pujar ◽  
C. R. Das ◽  
Nanda Gopal Krishna ◽  
C. Mallika ◽  
...  
Keyword(s):  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Combined Effects

Effect of severe plastic deformation by ECAP on corrosion behaviour of aluminium alloy AA 7075

2016 ◽  
Vol 81 (2) ◽  
pp. 55-61 ◽  
Author(s):  
M. Ilieva ◽  
R. Radev
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Equal Channel Angular Pressing ◽  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Chloride Concentration ◽  
Chloride Ions ◽  
Angular Pressing ◽  
Pitting Corrosion Resistance ◽  
Aa 7075

Purpose: The present study compares the corrosion behaviour of overaged AA 7075 before and after equal channel angular pressing ECAP in two media, containing chlorides, in order to answer the question how grain refinement of aluminium alloys influences their corrosion properties.Design/methodology/approach: The effect of equal channel angular pressing ECAP on corrosion behaviour of aluminium alloy AA 7075 was studied in two water solutions, containing chloride ions: 1) 0.01 M Na2SO4 with addition of 0.01%Cl-, and 2) 3g/l H2O2 and 57g/l NaCl. The changes in electrochemical characteristics, provoked by grain size refinement after equal channel angular pressing ECAP, were found using potentiodynamic polarisation. Steady state potential, corrosion potential, corrosion current density; breakdown (pitting) potential of overaged and deformed by equal channel angular pressing ECAP aluminium alloy AA 7075 were measured.Findings: In the environment with lower chloride concentration equal channel angular pressing ECAP process led to increase in pitting corrosion resistance and in the medium with higher chloride concentration - to decrease in pitting corrosion resistance. That way grain refinement does not demonstrate a uni-directional influence on corrosion resistance of AA 70775.Research limitations/implications: The results suggest the possibility for development of materials having the same chemical composition but with different corrosion resistance to different environments.Originality/value: The paper presents the corrosion behaviour of ultrafine-grained aluminium alloy AA 7075 and the influence of the chloride ions concentration in the corrosion medium on this behaviour.

A chemo-damage-transport model for chloride ions diffusion in cement-based materials: Combined effects of sulfate attack and temperature

2021 ◽  
Vol 288 ◽  
pp. 123121
Author(s):  
Penggang Wang ◽  
Rui Mo ◽  
Sen Li ◽  
Jun Xu ◽  
Zuquan Jin ◽  
...  
Keyword(s):  
Transport Model ◽  
Sulfate Attack ◽  
Chloride Ions ◽  
Combined Effects ◽  
Cement Based Materials ◽  
Chloride Ions Diffusion

Electrochemical Investigation Cu Corrosion Behaviour of Electronic Circuit Board in Base Electrolyte

2014 ◽  
Vol 556-562 ◽  
pp. 141-144
Author(s):  
Zhi Hua Tao ◽  
Bin Leng ◽  
Chong Wang ◽  
Ding Jun Xiao ◽  
Ze Tan ◽  
...  
Keyword(s):  
Potentiodynamic Polarization ◽  
Electronic Circuit ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Circuit Board ◽  
Corrosion Mechanism ◽  
Base Electrolyte ◽  
Eis Measurements ◽  
Inhibition Performance ◽  
Cu Corrosion

The eleetronic material, or even the whole equipments may be destroyed by very slight corrosion, so it is important to study the corrosion mechanism and corrosion protections. The Cyproconazole as a Cu corrosion inhibitor for Electronic Circuit Board in the base electrolyte (containing 70 ppm chloride ions, 0.54 mol/L H2SO4and 0.8 mol/L CuSO4) was investigated using polarization curves and AC impedance. The results showed that the inhibition performance of the Cyproconazole depended on the concentration of the inhibitor and the highest inhibition efficiency of the Cyproconazole reached 99.9% at 1×10-3mol/L in the base electrolyte. The results obtained from EIS measurements are in good agreement with that obtained from potentiodynamic polarization. Potentiodynamic polarization studies clearly revealed that Cyproconazole adsorption acted essentially as the mixed-type inhibitor.

The effect of hydroquinone and methoxypropylamine on the pitting corrosion behaviour of A-470 low alloy turbine disc steel

1993 ◽  
Vol 34 (8) ◽  
pp. 1289-1297 ◽  
Author(s):  
V Otieno-Alego ◽  
G.A Hope ◽  
H.J Flitt ◽  
D.P Schweinsberg
Keyword(s):  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Turbine Disc

scholarly journals Experimental study of the influence of crack width due to corrosion behaviour using different measurement methods and different exposures

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Corrosion Behaviour ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Surface Corrosion ◽  
Potential Mapping

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.

Low Potential Pitting Corrosion of Ni-Cr-Fe Alloys in Chloride Plus Thiosulfate Solutions: Determination of Potential and Concentration Boundaries

CORROSION ◽  
10.5006/3562 ◽  
2020 ◽  
Vol 76 (8) ◽  
pp. 786-795
Author(s):  
Abraham A. Becerra Araneda ◽  
Mariano A. Kappes ◽  
Martín A. Rodríguez ◽  
Ricardo M. Carranza
Keyword(s):  
Pitting Corrosion ◽  
Chloride Ions ◽  
Aged Alloy ◽  
Electrochemical Tests ◽  
Alloy 800 ◽  
Chloride Threshold ◽  
Alloy 690 ◽  
Fe Alloys ◽  
Thiosulfate Concentration

Low potential pitting corrosion (LPPC) of Alloys 690 and 800 (UNS N06690 and N08800) was studied in neutral solutions, containing chloride ions from 0.1 M to 1 M and thiosulfate ions from 5 × 10−5 M to 10−3 M. LPPC occurred close to the corrosion potential (–0.25 VAg/AgCl) by a synergic effect of the chloride and thiosulfate ions. The threshold concentrations of aggressive species for LPPC occurrence were identified by potentiostatic tests with mechanical scratching of the surface, which yielded more conservative estimations compared to other electrochemical tests. The ranges of potential and concentration of chloride and thiosulfate where LPPC occurred and where it merged with the conventional chloride pitting were determined. The lowest threshold concentrations were measured in Alloy 800, with a lower Cr content than Alloy 690. Thermally-aged Alloys 800 and 690 had lower resistance to LPPC than the corresponding solution-annealed material. In 1 M chloride-based solutions, for aged Alloy 800, LPPC occurred at a thiosulfate concentration as low as 5 × 10−5 M; in 10−3 M thiosulfate-based solutions, the chloride threshold was 0.1 M. For thermally-aged alloys, pits propagated intergranulary in some experiments. In solutions with chloride and thiosulfate concentrations close to the threshold required for pitting, repassivation of LPPC was observed after a sustained period of pit growth, originally initiated by scratching the surface. Such a repassivation has not been reported before in the literature in chloride and thiosulfate solutions. Two possible explanations were presented for this phenomenon.

scholarly journals Low Stress Abrasion-Corrosion of High-Cr White Cast Iron: Combined Effects of Particle Angularity and Chloride Ions

2019 ◽  
Vol 166 (13) ◽  
pp. C382-C393
Author(s):  
Mobin Salasi ◽  
Mariano Iannuzzi ◽  
William Rickard ◽  
Zakaria Quadir
Keyword(s):  
Cast Iron ◽  
White Cast Iron ◽  
Chloride Ions ◽  
Combined Effects
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