Molybdates as Corrosion Inhibitors in the Presence of Chlorides

CORROSION ◽  
1976 ◽  
Vol 32 (7) ◽  
pp. 263-266 ◽  
Author(s):  
E. A. LIZLOVS
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Potentiodynamic Polarization ◽  
Room Temperature ◽  
Corrosion Inhibitors ◽  
Corrosion Potential ◽  
Chloride Content ◽  
Passive State ◽  
Chloride Sulfate ◽  
Polarization Studies

Abstract The effect of the molybdate ion (MoO4=) concentration on the corrosion inhibition of 1010 steel was investigated in aerated chloride/sulfate-containing solutions. The chloride content was 304 ppm Cl−, and the sulfate was 352 ppm SO4=. Weight loss measurements and electrochemical methods were employed for the investigation. The pH was controlled at 8.7. Weight loss measurements indicated that about 165 ppm of molybdate reduced the corrosion rate below 10 mg·dm−2/day at room temperature. At 160 F (71 C), about 50 ppm of molybdate reduced the corrosion rate to 4 to 5 mg·dm−2/day. The potentiodynamic polarization studies and the examination of corrosion potential and immersion time relationship disclosed that the molybdate ion acts as a passivating agent in the presence of oxygen. Passivity was also obtained under potentiodynamic polarization conditions in a nitrogenated solution. No passivation was obtained in the absence of the molybdate ion. For spontaneous passivation, both molybdate and oxygen (oxidizing agent) were needed. Corrosion rates in a passive state according to the polarization curve should be nil.

Corrosion Behaviour of Amorphous and Nanocrystalline Ti60Ni40 in Aqueous HNO3 Solution

2009 ◽  
Vol 67 ◽  
pp. 173-178 ◽  
Author(s):  
Shubhra Mathur ◽  
Rishi Vyas ◽  
S.N. Dolia ◽  
Kanu Sachdev ◽  
S.K. Sharma
Keyword(s):  
Weight Loss ◽  
Potentiodynamic Polarization ◽  
Corrosion Current Density ◽  
Room Temperature ◽  
Corrosion Behaviour ◽  
Aqueous Media ◽  
Amorphous State ◽  
Corrosion Current ◽  
Nanocrystalline State ◽  
Polarization Studies

Potentiodynamic polarization studies were carried out on amorphous, nanocrystalline and crystalline states of the alloy Ti60Ni40 in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous solutions at room temperature. It was observed that the amorphous state exhibited higher corrosion current density than that by the nanocrystalline state. These results are corroborated by the weight loss studies performed on the different structural states of Ti60Ni40 alloy in 0.1 M HNO3, 0.5 M HNO3 and 1 M HNO3 aqueous media. Thus the nanocrystalline state is least prone to corrosion than the amorphous and the crystalline states.

scholarly journals Novel pyrimidine-bichalcophene derivatives as corrosion inhibitors for copper in 1 M nitric acid solution

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25314-25333
Author(s):  
Mai A. Khaled ◽  
Mohamed A. Ismail ◽  
Ahmed. A. El-Hossiany ◽  
Abd El-Aziz S. Fouda
Keyword(s):  
Weight Loss ◽  
Electrochemical Impedance Spectroscopy ◽  
Nitric Acid ◽  
Impedance Spectroscopy ◽  
Acid Solution ◽  
Nitric Acid Solution ◽  
Potentiodynamic Polarization ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Pyrimidine Derivatives

This study targets the investigation of three pyrimidine derivatives (MA-1230, MA-1231, MA-1232) for the prevention of corrosion on copper in 1 M HNO3via weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques.

scholarly journals Dissolution of chromium in sulfuric acid

2002 ◽  
Vol 67 (11) ◽  
pp. 777-782 ◽  
Author(s):  
Dragutin Drazic ◽  
Jovan Popic
Keyword(s):  
Corrosion Rate ◽  
Room Temperature ◽  
Corrosion Potential ◽  
Analytical Data ◽  
Electrochemical Corrosion ◽  
Spectrophotometric Analysis ◽  
Weight Loss Method ◽  
Loss Method ◽  
Anomalous Dissolution

By combining electrochemical corrosion rate measurements and spectrophotometric analysis of the electrolyte it was shown that at room temperature chromium dissolves in deaerated 0.1M Na2SO4 + H2SO4 (pH1) solution as Cr(II) and Cr(III) ions in he ratio Cr(II):Cr(III)?7:1. This process was stable over 4h without any detectable change. The total corrosion rate of chromium calculated from the analytical data is about 12 times higher, than that determined electrochemically by cathodic Tafel line extrapolation to the corrosion potential. This finding was confirmed by applying the weight-loss method for the determination of the corrosion rate. This enormous difference between these experimentally determined corrosion rates can be explained by the rather fast, "anomalous" dissolution process proposed by Kolotyrkin and coworkers (chemical reaction of Cr with H2O molecules) occurring simultaneously with the electrochemical corrosion process.

Surface morphology studies and kinetic-thermodynamic characterization of steels treated in 5.0 M HCl medium: hot-dip galvanizing application

2018 ◽  
Vol 65 (2) ◽  
pp. 176-189 ◽  
Author(s):  
Younes El Kacimi ◽  
Mouhsine Galai ◽  
Khaoula Alaoui ◽  
Rachid Touir ◽  
Mohamed Ebn Touhami
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Potentiodynamic Polarization ◽  
Phosphorus Content ◽  
Surface Heterogeneity ◽  
Protective Film ◽  
Content Type ◽  
3D Profilometry ◽  
Adsorption Processes ◽  
Hcl Solution

Purpose The purpose of this paper is to study the effect of silicon and phosphorus content in steel suitable for galvanizing on its corrosion and inhibitor adsorption processes in steels/cetyltrimethylammonium bromide combined and KI (mixture)/5.0 M hydrochloric acid systems has been studied in relation to the temperature using chemical (weight loss), Tafel polarization, electrochemical impedance spectroscopy (EIS), scanning electronic microscope (SEM) analysis and Optical 3D profilometry characterization. All the methods used are in reasonable agreement. The kinetic and thermodynamic parameters for each steels corrosion and inhibitor adsorption, respectively, were determined and discussed. Results show that the adsorption capacity for Steel Classes A and B are better than Steel Class C surfaces depending on their silicon and phosphorus content. Surface analyses via SEM and Optical 3D profilometry was used to investigate the morphology of the steels before and after immersion in 5.0 M HCl solution containing mixture. Surface analysis revealed improvement of corrosion resistance of Steels Classes A and B in the presence of mixture more than Classes C. It has been determined that the adsorbed protective film on the steels surface heterogeneity markedly depends on steels compositions, that is, the heterogeneity increases with decreasing silicon and phosphorus content. Design/methodology/approach The effect of silicon and phosphorus content in Steels Classes A, B and C on its corrosion and inhibitor mixture adsorption processes in 5.0 M HCl solution has been studied by weight loss, potentiodynamic polarization, EIS and surface analysis. Findings The inhibition efficiency of mixture follows the order: (Steel Class A) > (Steel Class B) > Steel Class C) and depends on their compositions in the absence of mixture according on their silicon and phosphorus content, that is, the corrosion rate increases with increasing of the silicon and phosphorus content. A potentiodynamic polarization measurement indicates that the mixture acts as mixed-type inhibitor without changing the mechanism of corrosion process for the three classes of mild steels. Originality/value Corrosion rate mild steels in 5.0 M HCl depends on their compositions in the absence of mixture according to their silicon and phosphorus content, that is, the corrosion rate increases with increasing silicon and phosphorus content. The adsorbed protective film on the steels surface heterogeneity markedly depends on steels class’s compositions, that is, the heterogeneity increases with decreasing silicon and phosphorus content.

scholarly journals Inhibition of Brass Corrosion in Acid Medium Using Thiazoles

2013 ◽  
Vol 14 ◽  
pp. 87-102
Author(s):  
K.K. Taha ◽  
Musa E. Mohamed ◽  
S.A. Khalil ◽  
S.A. Talab
Keyword(s):  
Weight Loss ◽  
Thermal Properties ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Rate ◽  
Heat Exchangers ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Zinc Dissolution

Brass as an alloy composed mainly of copper is great industrial uses such as heat exchangers and similar other facility due to its good thermal properties. Due to the presence of the considerable ratio of zinc the alloy suffers from zinc dissolution or dezincification. Dezincification rate increases with the increase in the ratio of zinc in the alloy. In this study benzothiazole (BTH) and its substituent’s 2-methylbenzothiazole (MeBTH), 2-aminobenzothiazole (ABTH), 2-mercaptobenzothiazole (MBTH) and 2-phenylbenzothiazole (PhBTH) have been used as corrosion inhibitors for α-brass in stirred 0.1 M HClO4. The methods of investigation include weight loss, Tafel and linear polarizations and electrochemical impedance spectroscopy. The order of inhibition efficiency (%E) was calculated and the values obtained has indicated the sequence of inhibition efficiency was found to be BTH < MeBTH < ABTH < PhBTH < MBTH. The calculated values of thermodynamic parameters support this order. The inhibitors were found to suppress the corrosion rate by the formation of films which were identified by IR, SEM and EDAX techniques.

scholarly journals GREEN INHIBITORS FOR CORROSION PROTECTION OF N80 CARBON STEEL IN 1M HCl AQUEOUS SOLUTIONS

2012 ◽  
Vol 20 (20) ◽  
pp. 77-98
Author(s):  
A. H. EL-ASKALANY ◽  
S. I. MOSTAFA ◽  
A. M. EID
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Potentiodynamic Polarization ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Electrochemical Impedance ◽  
Physical Adsorption ◽  
Polarization Studies ◽  
Inhibitive Action ◽  
Good Agreement

The inhibitive action of Saponinic extract of both Zygophylium album and Zygophylium Egyptian leaves which could serve as eco-friendly materials was investigated on the corrosion of N80 carbon steel in 1 M HCl solution. The techniques employed for the study were weight loss measurements. potentiodynamic polarization, electrochemical frequency modulation (EFM), and electrochemical impedance spectroscopy (EIS). The results obtained show that these extracts could serve as an effective inhibitor for N80 carbon steel. The percentage inhibition increases with increasing concentration of the inhibitor at 25 °C The percentage inhibitor efficiency above 90% was obtained at a concentration of 700 ppm for both extracts. The corrosion rates of steel and inhibitive efficiencies obtained from impedance and polarization measurements were in good agreement with those obtained from weight loss measurements. Potentiodynamic polarization studies clearly reveal that both extracts act as mixed-type inhibitors The study shows that the inhibition efficiency decreased with the temperature rise of the medium. Heat of adsorption and thermodynamic parameters and indicated that the adsorption process is mainly controlled by the physical adsorption process.

Corrosion of Copper in 1 M NaCl under Strictly Anoxic Conditions

2003 ◽  
Vol 807 ◽  
Author(s):  
Martin Bojinov ◽  
Timo Laitinen ◽  
Kari Mäkelä ◽  
Margit Snellman ◽  
Lars Werme
Keyword(s):  
Weight Loss ◽  
Closed System ◽  
Room Temperature ◽  
Corrosion Potential ◽  
Native Oxide ◽  
Anoxic Conditions ◽  
Homogeneous Oxidation ◽  
On Line ◽  
Chemical Conditions ◽  
Line Resistance

ABSTRACTThe corrosion of copper in 1 M NaCl has been investigated at room temperature and at 80°C by an on-line resistance probe, solution analysis of dissolved copper and weight loss measurements. At room temperature, corrosion of the copper as indicated by an increase of the probe resistance has been detected during the first 60–80 h of exposure. After the corrosion potential has reached the immunity region of Cu, a decrease in the resistance of the sensor is observed, probably due to redeposition of Cu from the solution. It can be concluded that the corrosion of copper at room temperature virtually stops after 60–80 h due to the anoxic conditions established in the experiments. The similarity in the trends of the corrosion and redox potential during exposure seems to indicate that Cu(II) contained in the native oxide on Cu and/or formed by homogeneous oxidation of Cu(I) during the initial oxic period of exposure acts as a redox-agent determining the chemical conditions in the closed system.

scholarly journals High Temperature Effectiveness of Ginger Extract as Green Inhibitor for Corrosion in Mild Steel

2019 ◽  
Vol 11 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Muhammad Sohail ◽  
Fayaz Hussain ◽  
Ali Dad Chandio ◽  
Maryam Sheikh
Keyword(s):  
Corrosion Rate ◽  
Mild Steel ◽  
Room Temperature ◽  
Corrosion Inhibitors ◽  
Raw Material ◽  
Ginger Extract ◽  
Green Inhibitor ◽  
Ambient Temperatures ◽  
Linear Polarization Resistance ◽  
Corrosion Rates

Corrosion is one of the major problems of mild steels in acidic medium. This can be minimized by the application of corrosion inhibitors, however; the most of inhibitors are toxic in nature. Therefore inhibitors from green sources are highly desirable to maintain the sustainability of the environmental system. Consequently, in this study ginger was selected; its juice extracted mechanically and used as an inhibitor. The different concentrations of ginger extract such as 0.25ml, 0.5ml, 0.75ml and 1ml were mixed in 0.1 M HCl solution to record the effect of inhibitor on corrosion rate at room temperature and at an elevated temperature of 50ᵒC. Electrochemical linear polarization resistance (LPR) tests were carried out to determine the corrosion rates at both temperatures with different additions of the inhibitor respectively. The LPR test uses three electrodes, first electrode of AISI 1019 (mild steel), second electrode is standard electrode of saturated calomel while the third electrode consists of graphite, which is called counter electrode, to measure potential difference. The whole assembly was dipped in the solution having varying concentration of inhibitors. The corrosion rate was found to be higher in the absence of ginger- extract. Conversely, the corrosion rate was dramatically reduced more prominently at 50oC but was less effective at Troom; with the trace-additions of ginger-inhibitor. So this research would be the good contribution to overcome the deterioration of mild steel and increase its life at ambient temperatures, by using economically available environmentally-friendly organic compound specially the use of locally available raw material should be focused.

Effectiveness of an Inorganic Corrosion Inhibitor in Pore Solution Containing Sodium Chloride

2014 ◽  
Vol 556-562 ◽  
pp. 158-161 ◽  
Author(s):  
Xing Guo Feng ◽  
Guang Hui Dong ◽  
Jun Yan Fan
Keyword(s):  
Weight Loss ◽  
Sodium Chloride ◽  
Corrosion Rate ◽  
Corrosion Current Density ◽  
Inhibition Efficiency ◽  
Corrosion Potential ◽  
Pore Solution ◽  
Electrochemical Measurement ◽  
Corrosion Current ◽  
Organic Inhibitor

Combining use electrochemical measurement and weight loss testing, the inhibition efficiency of an organic inhibitor was studied in a chloride contaminated solution. The results showed that the added inhibitor can enhance the corrosion potential and decreased the corrosion current density of rebar. The weight loss testing confirmed that the inhibitor reduced the corrosion rate of rebar by 80% in the chloride containing solution. Moreover, the linear polarization results are consistent with the weight loss testing, which suggests that the former is an effective method to estimate the inhibition efficiency of inhibitors.

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