scholarly journals Inhibition of Q235 Carbon Steel by Calcium Lignosulfonate and Sodium Molybdate in Carbonated Concrete Pore Solution

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 518 ◽  
Author(s):  
Bing Lin ◽  
Yu Zuo
Keyword(s):  
Carbon Steel ◽  
Surface Analysis ◽  
Pore Solution ◽  
Sodium Molybdate ◽  
Solution Ph ◽  
Pitting Potential ◽  
Inhibition Effect ◽  
Surface Analysis Techniques ◽  
Q235 Carbon Steel ◽  
Synergistic Inhibition Effect

The inhibition effect and mechanism of a compound calcium lignosulfonate (CLS) and sodium molybdate inhibitors for Q235 carbon steel in simulated carbonated concrete pore solution (pH 11.5) with 0.02 mol/L NaCl are studied using electrochemical and surface analysis techniques. The results show that in carbonated simulated concrete pore (SCP) solution CLS and Na2MoO4 show a synergistic inhibition effect. The compound inhibitor can be defined as mix-type inhibitor. With 400 ppm CLS plus 600 ppm Na2MoO4, the pitting potential moves positively about 200 mV, and the inhibition efficiency reaches 92.67%. After 24 h immersion, the IE% further increases up to 99.2%. The surface analysis results show that Na2MoO4 could promote stability of the passive film, and the insoluble molybdenum compounds and CaO/Ca(OH)2, together with adsorbed CLS, deposit on the steel surface, forming a complex film. The compounded film effectively inhibits corrosion of the steel.

Effect of aluminum Tripolyphosphate on pitting initiation on carbon steel in chloride contaminated concrete pore solution

2019 ◽  
Vol 66 (5) ◽  
pp. 603-612
Author(s):  
Xiangyu Lu ◽  
Leyuan Zhang ◽  
Xingguo Feng ◽  
D. Chen ◽  
Yu Zuo
Keyword(s):  
Carbon Steel ◽  
Scale Parameter ◽  
Pore Solution ◽  
Inhibition Mechanism ◽  
Flat Band ◽  
Pitting Potential ◽  
Content Type ◽  
Distribution Of The Maximum ◽  
Maximum Current ◽  
Extreme Distribution

Purpose Aluminum tripolyphosphate was used as a corrosion inhibitor in a simulated concrete pore solution. For studies of the inhibition mechanism of aluminum tripolyphosphate on the carbon steel, its influence on the pitting initiation on the carbon steel in a Cl− containing pore solution were investigated. Design/methodology/approach Potentiodynamic polarization curves, Mott–Schottky plots and potentiostatic polarization of the carbon steel in the pore solution with different content of aluminum tripolyphosphate were measured, as well as the optical micrographs of pitting on the carbon steel was observed. Findings The metastable pitting potential and the stable pitting potential increased, while the donor density and the flat band potential decreased with the concentration of aluminum tripolyphosphate in solution. Furthermore, the initiation of pitting was suppressed, as well as the transition from metastable to stable pitting was hindered by the aluminum tripolyphosphate. The scale parameter (a), in the extreme distribution of the maximum current peak, could be used to predict the transition from metastable to stable pitting. Originality/value The inhibition mechanism of aluminum tripolyphosphate on carbon steel in pore solution was revealed. It suppresses the initiation of pitting and hinders the transition from metastable to stable pitting. Furthermore, a parameter defined as the scale parameter (a) in the extreme distribution of the maximum current peak was introduced to predict the transition from metastable to stable pitting.

scholarly journals Study on Synergistic Corrosion Inhibition Effect between Calcium Lignosulfonate (CLS) and Inorganic Inhibitors on Q235 Carbon Steel in Alkaline Environment with Cl−

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4200
Author(s):  
Bing Lin ◽  
Junlei Tang ◽  
Yingying Wang ◽  
Hu Wang ◽  
Yu Zuo
Keyword(s):  
Carbon Steel ◽  
Metal Oxides ◽  
Corrosion Inhibition ◽  
Steel Surface ◽  
Film Deposition ◽  
General Corrosion ◽  
Adsorption Film ◽  
Inhibition Effect ◽  
Q235 Carbon Steel ◽  
Complex Film

The synergistic corrosion inhibition effect between calcium lignosulfonate (CLS) and three kinds of inorganic inhibitors (Na2MoO4, Na2SnO3, and NaWO4) with various molar ratios on Q235 carbon steel in alkaline solution (pH 11.5) with 0.02 mol/L NaCl was investigated by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization, scanning electron microscopy, and X-ray photoelectron spectroscopy. Molybdate and stannate in hybrid inhibitor could promote the passivation of steel and form a complex film, which could suppress the corrosion effectively. Moreover, the insoluble metal oxides in the complex film formed by three kinds of inorganic inhibitor could help the adsorption of CLS onto the steel surface. The CLS molecules could adsorb onto the steel surface and metal oxides to form an adsorption film to protect the steel from corrosion. A three-layer protection film formed by a hybrid inhibitor, including passivation film, deposition film, and adsorption film, would effectively inhibit the corrosion reactions on the steel surface. The CLS compound with molybdate with the ratio of 2:3 shows the best inhibition effect on both general corrosion and localized corrosion.

SIGNIFICANCE OF π–ELECTRONS IN THE DESIGN OF CORROSION INHIBITORS FOR CARBON STEEL IN SIMULATED CONCRETE PORE SOLUTION

CORROSION ◽  
10.5006/3844 ◽  
2021 ◽  
Author(s):  
Ahmed Mohamed ◽  
D. Visco Jr. ◽  
David M. Bastidas
Keyword(s):  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Corrosion Inhibitors ◽  
Pore Solution ◽  
Molecular Descriptor ◽  
Structure Property ◽  
Multilinear Regression ◽  
Pitting Potential ◽  
Novel Approach ◽  
Inhibition Performance

Chloride–induced corrosion of carbon steel reinforcements is one of the most important failure mechanisms of reinforced concrete structures. Organic corrosion inhibitors containing different functional groups were analyzed using cyclic potentiodynamic polarization to determine their effect on the pitting potential of carbon steel reinforcements in a 0.1 M Cl– contaminated simulated concrete pore solution. It was found that organic compounds with π–electrons in a functional group had better performance. This is attributed to the high density of highest occupied molecular orbital energies found in carboxyl group π–bond. Accordingly, increasing the tendency of donating π–electrons to the appropriate vacant d–orbital of the carbon steel, forming an adsorption film. The best corrosion inhibition performance was achieved by poly–carboxylates followed by alkanolamines and amines. In addition, a novel approach to show the significance of corrosion inhibition phenomenon was applied by developing a quantitative structure-property relationship using the Signature molecular descriptor which correlates the occurrences of atomic Signatures in a dataset to a property of interest using a forward stepping multilinear regression. The atomic Signature fragment capturing π–bond was the most influential of all the fragments, which underscores the significance of π–bond electrons in the adsorption process. It was demonstrated that the [O](=[C]) atomic Signature plays a crucial role in the inhibition process at all heights, corroborating the experimental results.

scholarly journals Corrosion inhibition of carboxylate inhibitors with different alkylene chain lengths on carbon steel in an alkaline solution

RSC Advances ◽  
2019 ◽  
Vol 9 (13) ◽  
pp. 7065-7077 ◽  
Author(s):  
Bing Lin ◽  
Yu Zuo
Keyword(s):  
Carbon Steel ◽  
Quantum Chemical Calculations ◽  
Surface Analysis ◽  
Corrosion Inhibition ◽  
Alkaline Solution ◽  
Quantum Chemical ◽  
Pore Solution ◽  
Electrochemical Measurement ◽  
Q235 Steel ◽  
Chain Lengths

The inhibition effects of carboxylate compounds with different alkylene chain lengths on Q235 steel in simulated carbonation concrete pore solution were studied using quantum chemical calculations, electrochemical measurement and surface analysis.

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