High-temperature corrosion of phosphate completion fluid and corrosion inhibition method by membrane transformation

By analyzing the corrosion of phosphate completion fluid on the P110 steel at 170 °C, the high-temperature corrosion mechanism of phosphate completion fluid was revealed, and a corrosion inhibition method by membrane transformation was proposed and an efficient membrane-forming agent was selected. Scanning electron microscope (SEM) images, X-ray energy spectrum and X-ray diffraction results were used to characterize the microscopic morphology, elemental composition and phase composition of the precipitation membrane on the surface of the test piece. The effect and mechanism of corrosion inhibition by membrane transformation were clarified. The phosphate completion fluid eroded the test piece by high-temperature water vapor and its hydrolyzed products to form a membrane of iron phosphate corrosion product. By changing the corrosion reaction path, the Zn2+ membrane-forming agent could generate KZnPO4 precipitation membrane with high temperature resistance, uniform thickness and tight crystal packing on the surface of the test piece, which could inhibit the corrosion of the test piece, with efficiency up to 69.63%. The Cu2+ membrane-forming agent electrochemically reacted with Fe to precipitate trace elemental Cu on the surface of the test piece, thus forming a protective membrane, which could inhibit metal corrosion, with efficiency up to 96.64%, but the wear resistance was poor. After combining 0.05% Cu2+ and 0.25% Zn2+, a composite protective membrane of KZnPO4 crystal and elemental Cu was formed on the surface of the test piece. The corrosion inhibition efficiency reached 93.03%, which ensured the high corrosion inhibition efficiency and generated a precipitation membrane resistant to temperature and wear.

Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect between PESA and Zn2+ or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2+ and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic structure.

Corrosion Inhibition Synergism between Lanthanum(Ⅲ) Ion and 8-Hydroxyquinoline for Zinc in Hydrochloric Acid

The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.

Corrosion inhibition of layered double hydroxides for metal-based systems

Layered double hydroxide(LDH),a kind of 2D layered materials,has been recognized as the promising anticorrosion materials for metal and its alloy.The microstructure,physical/chemical properties,usage in corrosion inhibition and inhibition performance of LDH have been studied separately in open literature.However,there is a lack of a complete review to summarize the status of LDH technology and the potential R&D opportunities in the field of corrosion inhibition.In addition,the challenges for LDH in corrosion inhibition of metal-based system have not been summarized systematically.Herein,we review recent advances in the rational design of LDH for corrosion inhibition of metal-based system(i.e.Mg alloy,Al alloy,steel and concrete)and high-throughput anticorrosion materials development.By evaluating the physical/chemical properties,usage in metal-based system and the corrosion inhibition mechanism of LDH,we highlight several important factors of LDH for anticorrosion performance and common features of LDH in applying different metal alloys.Finally,we provide our perspective and recommendation in this field,including high-throughput techiniques for combinatorial compositional design and rapid synthesis of anticorrosion alloys,with the goal of accelerating the development and application of LDH in corrosion inhibition of metal-based system.

Corrosion Inhibition of Carbon Steel in Hot Hydrochloric Acid Solutions

The dissolution of carbon steel in 5% HCl in the temperature range of 30~90℃ was inhibited by two organic compounds having the general formula: ClR NH2(CH2)n NH2 RCl where R is a benzyl group. The behaviour of these inhibitors in acidic medium were investigated using weight loss method, open circuit potential and linear polarization technique. These inhibitors provided satisfactory corrosion inhibition for carbon steel in hydrochloric acid solutions even at higher temperature and acid concentration (10%). The electrochemical results showed that the polarization resistance (Rp) values increased with increasing inhibitor concentration, also the corrosion current decreased and a higher inhibition efficiency was obtained. The protective properties of these two organic inhibitors were attributed to the chemisorption mechanism

ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY STUDY OF CORROSION INHIBITION OF MODIFIED LIGNOSULPHONATE FOR CARBON STEEL

The corrosion inhibition for carbon steel in circulating cooling water by modified lignosulphonate has been investigated using electrochemical impedance spectroscopy technique. Results show that the inhibition efficiency of modified lignosulphonate GCL2 is a great improvement on that of lignosulphonate. The maximum inhibition efficiency of GCL2 reaches 99.21% at the concentration of 400mg·L^-1 at 303K. The corrosion inhibition of GCL2 is attributed to forming adsorption film on the metal surface for the electrochemical impedance spectroscopy in GCL2 solution shows more than one time-constant.Moreover,results also indicate that it is more efficient in stirring solution than in still solution for GCL2 because the constant of adsorption in stirring solution is much larger than that in still solution. The adsorption of inhibitor GCL2 follows Langmuir＇s adsorption isotherm.

Corrosion inhibition of carbon steel in hydrochloric acid by cationic arylthiophenes as new eco-friendly inhibitors: Experimental and quantum chemical study

This study describes the adsorption behavior of three arylthiophene derivatives namely:2-(4-amidino-3-fluorophenyl)-5-[4-methoxy phenyl] thiophene dihydrochloride salt(MA-1217),2-(4-amidinophenyl)-5-[4-chlorophenyll thiophene dihydrochloride salt(MA-1316) and 2-(4-amidino-3-fluorophenyl)-5-[4-ch lorophenyllthiophene dihydrochloride salt(MA-1312) at C-steel in 1.0 mol·L^(-1) HCl interface using experimental and theoretical studies.Electrochemical and mass loss measurements showed that the inhibition efficiency(IE) of the arylthiophene derivatives increases with increasing concentrations and exhibited maximum efficiency 89% at 21×10^(-6) mol·L^(-1)(MA-1217) by mass loss method.The investigated arylthiophene derivatives obey the Langmuir adsorption isotherm.From polarization studies the arylthiophene derivatives act as mixed-type inhibitors.Surface analysis were carried out and discussed.The mode of orientation and adsorption of inhibitor molecules on C-steel surface was studied using molecular dynamics(MD) simulations.Quantum chemical parameters as well as the radial distribution function indices and binding energies confirm the experimental results.

An Electrochemical Study on the Corrosion Inhibition of Stainless Steel by Polyaniline Film

Polyaniline (PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with different thickness and structures. Protective properties of the PANI film for corrosion of stainless steel in 3% NaCl aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the stainless steel.

Antibacterial and Corrosion Inhibition Properties of SA-ZnO@ODA-GO@PU Super-Hydrophobic Coating in Circulating Cooling Water System

In order to solve the corrosion problem of circulating cooling water system,SA-ZnO@ODA-GO@PU super-hydrophobic coating was synthesized for pipeline protection.After hydrophobic modification,the contact angle(CA)of the coating was above 150°.The antibacterial ability of coating was essential for corrosion protection.SA-ZnO@ODA-GO can seriously damage the cell structure,make the cell content outflow,increase the leakage rate of protein,and make the bacteria unable to reach logarithmic growth phase within 24 h.The corrosion inhibition mechanism analysis of SA-ZnO@ODA-GO@PU coating indicated that the hydrophobic coating as a physical barrier can prevent the water molecules from entering the carbon steel and prevent the surface charge transfer.

Corrosion Inhibition Studies of Benzoxazole Derivates for N80 Steel in 1 M HCl Solution: Synthesis, Experimental, and DTF Studies

Three benzoxazole corrosion inhibitors, namely 2-(benzo [d]oxazol-2-yl)phenol (BOP), 6-(benzo [d]oxazol-2-yl)pyridin-2-ol (BOPO), and 2-(quinolin-2-yl) benzo [d]oxazole (QBO), were synthesized. Moreover, their corrosion inhibition performance for N80 steel in 1 M HCl solution at 303 K was measured by the electrochemical measurements and surface analysis studies. The results show that the inhibition efficiency of all corrosion inhibitors increases with the increase of concentration. At the same concentration, the order of inhibition efficiency is BOP < BOPO < QBO. Moreover, the studied inhibitors act as mixed-type inhibitors, and the adsorption of all inhibitors on N80 steel followed the Langmuir adsorption isotherm. Further, we have examined the effect of iodide ions on inhibition efficiency. The results show that BOP and KI are synergistic, BOPO and QBO are competitive adsorptions with KI. The quantum chemical parameters such as highest occupied molecular orbital, lowest unoccupied molecular orbital energy levels, and energy gap were calculated by the density functional theory (DTF). The relations between the inhibition efficiency and some quantum parameters have been discussed. The protective effect of the three inhibitors followed the sequence of BOP < BOPO < QBO. The results obtained from quantum chemicals and electrochemical were in reasonable agreement.

Inhibition mechanism of air nanobubbles on brass corrosion in circulating cooling water systems

Air nanobubbles(A-NBs)were used to inhibit the brass corrosion in circulating cooling water for the first time in the study.The results of mass loss method and electrochemical method showed that A-NBs had the obvious corrosion inhibition effect.The inhibition rate reached 52%at 35℃.The impedance and surface characterization results of corrosion samples indicated that the corrosion inhibition mechanisms of A-NBs mainly included adsorption of corrosion ions,promoting the formation of the passivation film on metal surface and the formation of the bubble layer and scale film on metal surface.A-NBs are potential excellent corrosion inhibitors.

Role of dissolved oxygen reduction in improvement inhibition performance of ascorbic acid during copper corrosion in 0.50 mol/L sulphuric acid

The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...

Effect of Hydrodynamic Conditions on Corrosion Inhibition of Cu-Ni(90/10)Alloy in Seawater and Sulphide Containing Seawater Using 1,2,3-Benzotriazole

Electrochemical studies of the effect of hydrodynamic conditions on corrosion inhibition of Cu-Ni （90/10） alloy in synthetic seawater and sulphide containing synthetic seawater by 1,2,3-benzotriazole （BTAH） are presented. Impedance, potentiodynamic polarization and cyclic voltammetric （CV） studies are employed in the present investigation. The studies are carried out by using Cu-Ni （90/10） alloy rotating disc electrode at different rotation speeds and at different immersion periods. Reynolds numbers at each rotation speed infer that the flow of seawater is laminar. With increasing rotation speed of the electrode immersed in seawater without sulphide and BTAH, both the charge transfer resistance （Rot） and film resistance （Rf^lm） are increased. However, in the presence of sulphide ions and without BTAH, both the Rot and Rf,m are found to decrease with increasing rotation speed at identical immersion periods. Interestingly, when BTAH is added to seawater or seawater containing sulphide, both the Rot and Rf,m are increased to such a great extent that an inhibition efficiency of 99.99% is obtained. In the presence of BTAH, the phase angle Bode plots are more broadened and the maximum values of phase angle are increased to a value close to 90~ as the rotation speed is increased. The BTAH film is highly protective even under hydrodynamic condition also. Potentiodynamic polarization studies infer that BTAH functions as a mixed inhibitor under hydrodynamic conditions also. CV studies reveal that the protective BTAH film is stable even at anodic potentials of ＋850 mV vs Ag/AgCI.

Effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives on corrosion inhibition of carbon steel in HCl solution:Molecular simulation and experimental validation

The effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives were investigated using quantum chemical calculation,molecular dynamics simulation and experimental techniques.Three corrosion inhibitors including symmetrical lauric acid imidazoline(SAI),tetracyclic lauric acid imidazoline(LAI),and symmetric stearic acid imidazoline(SPI)were synthesized and their inhibition performance was evaluated using weight loss measurement,electrochemical techniques and surface characterization.The results show that SAI and LAI with the same length of alkyl group chain,LAI with more imidazoline rings could supply a better inhibition performance since the increase of active sites.The increase of active sites attached to the metal surface may also change the distribution of corrosion inhibitor,which could limit inhibition performance improvement.While,SAI and SPI with the same number of imidazoline rings,SPI with longer alkyl group chain shows a better inhibition efficiency due to the better hydrophobic performance of alkyl groups.Among the three inhibitors,SPI shows the best inhibition performance,indicating that the alkyl group chain length affects the inhibition performance more obvious than the number of the imidazoline rings.

New Polymer Syntheses Part 60: A Facile Synthetic Route to Polyamides Based on Thieno[2,3-b]thiophene and Their Corrosion Inhibition Behavior

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer la with different kinds of diacid chlorides （including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4＇-azodibenzoyl, 3,3＇-azodibenzoyl, p-phenylene diacryloyl） in the presence of LiC1 and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy （including 1 H-NMR and 13 C-NMR） and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis （TGA）, wide-angle X-ray diffraction analysis （WAXD） and scanning electron microscopy （SEM）. Also, the corrosion inhibition behavior of selected examples ofpolyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol＇L-1 HCI was studied using potentiodynamic polarization （PDP） and electrochemical impedance spectroscopy （EIS） methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency （P, %） was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.

The Inhibition of Corrosion of Aluminum in Acid Environment by in situ Electrocoagulation of Polybutadienoie Acid

The dissolution rate of naked Al sbeet in the acidic solutions containing polybutadienoic acid(PBA) with pH vaIue of 0. 3～3. 0 at 20～60℃ has been determined by eIectrometry and gravimetry methods. The form of electroactive Al (m ) ions occurred on the anode and the behavior of electrocoagulation ofPBA have been approached. The results lndlcate that the superlor condltlon of electrocoagulation of watersoIuble nonsaturable low polymer PBA is the adoption of the eIectroactive Alions occurred in electrolytecontaining 1. 0 g. L-l PBA + 0. 2 mol' L-1 C'H,O, cltrlc acld with pH value of 3. 0 at 30℃. The mechanismof corrosion-inhibited 0r electrocoagulation resulted from the electroactive Al (lI) ions coordinate -COOHgroup of PBA and free l0ns of citric groups iuto the aluminum soaps with bicyclic structure are briefly discussed in tkis paper.

The Synergistic Effect of Quaternary Ammonium Canons on the Corrosion Inhibition of Fe by Inorganic Anions

The synergistic effect of tetrabutylammonium canon(TBA+)or N-hexadecylpyridinium cation(HDP+)and SCN-or I-in 0. 5 mol. L-1 H2SO4 solution on the corrosion inhibition or Armco iron was investigated by potentiodynamic polarization and polarization resistance measurements. The results show that the synergistic effect of HDP+ containing v-electron and anion is stronger than that of TBA+ and anion.The Joint adsorption models of canon and anion at electrode-solution interface are related to the structure and property of both ions by analyzing the desorption behaviours of both ions when the electrode is polarized anodically.

Synthesis, Crystal Structure and Inhibition Corrosion Effect of Bis-(1,1'-benzotriazoly)-α,ω-decoyldiamide

The title compound bis-（1,1 ＇-benzotriazoly）-a,co-decoyldiamide was synthesized by the reaction of benzotriazole with sebacoyl dichloride, and its structure was characterized by IR, 1H NMR and single-crystal X-ray diffraction. The crystal belongs to triclinic, space group PI with a = 5.5290（11）, b = 7.9410（16）, c = 12.401（3） A, α = 72.19,β = 78.87（3）, y = 82.82（3）°, V = 507.36（20）A3, C22H24N6O2, Mr = 404.47, Dc = 1.324 g/cm3, Z = 1, μ= 0.089 mm-1, F（000） = 214, the final R = 0.0481 and wR = 0.1342 for 1347 observed reflections with I 〉 2σ（I）. X-ray analysis revealed that the benzotriazole ring and carbonyl group were essentially planar. Potentiodynamic polarization study showed that inhibitor inhibited the anodic corrosion reactions, and it was an anodic type inhibitor.

Bio-inhibitive effect of an algal symbiotic bacterium on corrosion of magnesium in marine environment

It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.

Green Approach to Corrosion Inhibition of Mild Steel by Lignin Sulfonate in Acidic Media

The inhibition effect of lignin sulfonate against corrosion for mild steel in acidic solution has been examined by means of FTIR（fourier transform infrared spectroscopy）,FAA（flame atomic absorption）spectroscopy,SEM（scanning electron microscope）,EDS（energy dispersive X-ray spectroscopy）,and mass loss techniques.The results revealed that lignin is a beneficial inhibitor for mild steel corrosion in acidic medium.It has been further found that Langmuir adsorption isotherm is obeyed by the tested lignin′s adsorption over the surface of mild steel.The range of inhibition efficiency（IE）in 2mol·L^（-1） HCl was found to be 75.88%-87.88%for Reax 88 A,40.72%-60.32%for Reax 88 B,and 54.32%-63.03%for Reax 100 M,after immersed at 298 Kfor 24htime.