PITTING MECHANISM OF MILD STEEL IN MARGINALLY SOUR ENVIRONMENTS: PIT PROPAGATION BASED ON ACIDIFICATION BY CATALYTIC OXIDATION OF DISSOLVED HYDROGEN SULFIDE

CORROSION ◽  
10.5006/3858 ◽  
2021 ◽  
Author(s):  
Wei Zhang ◽  
Bruce Brown ◽  
David Young ◽  
Stephen Smith ◽  
Sytze Huizinga ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Mild Steel ◽  
Experimental Measurement ◽  
Thermodynamic Calculation ◽  
Room Temperature ◽  
Steel Surface ◽  
Saturation Degree ◽  
Transitional Metal ◽  
Dissolved Hydrogen ◽  
Dissolved O2

The present work studies pit propagation in marginally sour environments and proposes a credible mechanism. Both thermodynamic calculation and experimental measurement confirmed that H2S can be oxidized by traces of dissolved O2 into SO42- and H+ in the aqueous solutions near room temperature with the transitional metal ions serving as a catalyst. This acidification phenomenon would be more effective near the steel surface, especially inside a pit, where Fe2+ ions are most abundant. Therefore, the saturation degree of mackinawite would be lower inside the pit, which would prohibit the pitting from annihilation.

The fretting wear of mild steel from room temperature to 200°C

Wear ◽  
1972 ◽  
Vol 19 (2) ◽  
pp. 207-229 ◽  
Author(s):  
P.L. Hurricks
Keyword(s):  
Mild Steel ◽  
Room Temperature ◽  
Fretting Wear

Room temperature electrosynthesis of TinO2n-1 film and its bilayer with PNMPy on mild steel for corrosion protection in sulphuric acid

2021 ◽  
pp. 137996
Author(s):  
Nuran Özçiçek Pekmez ◽  
Merve Uğur ◽  
Erhan Karaca ◽  
Zeliha Ertekin ◽  
Kadir Pekmez
Keyword(s):  
Mild Steel ◽  
Sulphuric Acid ◽  
Corrosion Protection ◽  
Room Temperature

Corrosion Inhibition of Mild Steel by Electrodeposited Poly(M-Aminophenol) Coating

2021 ◽  
Vol 317 ◽  
pp. 498-505
Author(s):  
Sabrina M. Yahaya ◽  
Mohamad Kamal Harun ◽  
Ismaliza Ismail ◽  
Rosmamuhamadani Ramli
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Impedance Measurement ◽  
Barrier Properties ◽  
Electrical Circuit ◽  
Significant Drop ◽  
Mild Steel Surface ◽  
Barrier Resistance ◽  
And Performance

In this study, poly(m-aminophenol) (PMAP) coating was electrochemically synthesized by cyclic voltammetry (CV) on mild steel surface to investigate the effects of its barrier protection within the scope of its electrochemical impedance towards further oxidation of the mild steel substrates. The developed PMAP coating were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The barrier resistance ability of PMAP coating towards corrosion of mild steel was determined in 0.5 M aqueous sodium chloride solution (NaCl) at various immersion times by the electrochemical impedance spectroscopy (EIS). The barrier properties were interpreted through impedance measurement using Nyquist and Bode plots. Equivalent electrical circuit models derived from the plots were employed to describe the coating barrier behaviour and performance. Data obtained showed that, the oxidation peak of PMAP coating were observed at potential +1.0 V (Ag/AgCl). The micrograph of FESEM indicates the formation of a dense and continous PMAP coatings. In FTIR analyses, the presence of peak around 1082 cm-1 ascribed to C–O–C etheric linkage which supported the formation of electro polymerized PMAP coating on mild steel surface. EIS measurement revealed that, PMAP coatings experienced a significant drop in total impedance values with time followed by the development of an electrochemical reactions on coating/metal interface, which indicates the gradual degradation of the barrier resistance ability of the PMAP coatings.

scholarly journals THERMODYNAMIC PROPERTIES AND CHARACTERIZATIONS OF CHITOSAN NANO-PARTICLES CORROSION INHIBITION ON THE SURFACE OF MILD STEELIN PEAT WATER MEDIA

2016 ◽  
Vol 12 (1) ◽  
pp. 27
Author(s):  
Maria Erna ◽  
Emriadi Emriadi ◽  
Admin Alif ◽  
Syukri Arief
Keyword(s):  
Thermodynamic Properties ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Steel Surface ◽  
Complex Compounds ◽  
Nano Particles ◽  
Water Media ◽  
Weight Loss Method ◽  
Steel Surfaces ◽  
Loss Method

The thermodynamic properties and characterizations of corrosion inhibition of chitosan nano-particles on the surface of mild steel in peat water media had been studied using weight loss method at temperatures of 30 - 50 <sup>o</sup>C. Steel surfaces were characterized by FT-IR spectra and SEM-EDS morphology photos. The research found that the value of DG<sup>o </sup>approaching -40 kJmol<sup>-</sup><sup>1</sup>. The negative value of Gibbs free energy shows that the adsorption of inhibitor molecules on the surface of mild steel was achemisorption and it occurred spontaneously. Meanwhile, the values of DH<sup>o </sup>is also negative confirming that the adsoprtion of inhibitor molecules is an exothermic process. The value of DS<sup>o </sup>obtained is positive, it indicates hat the inhibitor molecules were adsorbed spontaneously on the mild steel surface. The analysis on mild steel surfaces hows that the nano-particle chitosan was adsorbed on the steel surface to form the complex compounds.

scholarly journals Inhibitive Effect of Costus afer Extracts on Mild Steel Corrosion in Acidic Medium

2016 ◽  
Vol 7 ◽  
pp. 60-67
Author(s):  
Lebe A. Nnanna ◽  
Wisdom O. John ◽  
Tochukwu E. Esihe ◽  
Kelechi C. Denkoro ◽  
Victor I. Okparaku ◽  
...  
Keyword(s):  
Mild Steel ◽  
Room Temperature ◽  
Inhibition Efficiency ◽  
Gravimetric Method ◽  
Steel Corrosion ◽  
Corrosion Process ◽  
Inhibition Effect ◽  
A Value ◽  
Mild Steel Corrosion ◽  
Costus Afer

Inhibition effect of Costusafer on mild steel in 0.5 M HCl was studied using gravimetric method at room temperature. It was found out that Costusafer inhibited the corrosion of mild steel in the acidic environment and that the efficiency of inhibition increased as the concentration of the inhibitor in the environment increased. The data was used to test different isotherms and it suited the Langmuir isotherm. A value of -15.995 kJmol-1 was gotten for the ∆Goads. This value showed that the extracts of Costusafer inhibited the corrosion process through physiosorption mechanism. The high value of inhibition efficiency of the extract as the concentration increased in rationalized in terms of the increase in herteroatoms, saponnins and tannins which are present in the extract.

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