New Class Of Corrosion Inhibitors Research Articles

Acalypha wilkesiana acid extract as a potential green inhibitor for corrosion of mild steel in acidic medium: Thermodynamics and kinetics study

The use of synthetic compounds as corrosion inhibitor is diminishing due to strict environmental regulations and toxic effects of the compounds on human beings and the environment. Consequently, there exists the need to develop a new class of corrosion inhibitors with low toxicity, eco-friendliness and good efficiency. Therefore, this study investigates the inhibitory potential of Acalypha wilkesiana (AWAE) extract on mild steel in 1M HCl using weight loss method. Experiments were performed by varying immersion period, concentration of the inhibitor and temperature. The results obtained showed a decrease in the corrosion rate of mild steel as the extract concentration increases while the inhibition efficiency increases with extract concentration. Effect of temperature on the inhibition efficiency showed an increase in inhibition efficiency with rise in temperature. The adsorption of the inhibitor on the mild steel surface in acid solution was found to obey the Langmuir adsorption isotherm. Calculated thermodynamic parameters revealed that the mechanism of the corrosion inhibition may be due to the chemical adsorption of the phyto-constituents on the surface of mild steel. Kinetic treatment of the data followed a first order reaction and the half-life values of the metal increase with increase in the extract concentration. Preliminary investigation of the phytochemical constituents showed that Acalypha wilkesiana contains tannin, flavonoid, saponin, alkaloid, steroid , terpenoid and some other compounds in trace quantity. FTIR results indicate that AWAE contains O and N atoms in functional groups and aromatic ring which meet the general consideration of a typical corrosion inhibitor.

An overview of the application of graphene-based materials in anticorrosive coatings

• Anti-corrosion performance of graphene and graphene based material coatings is reviewed. • Chemically modified graphene oxide emerged as new class of corrosion inhibitors. • Future development directions for graphene anti-corrosive coatings are anticipated. Graphene-based materials (GBMs) have an extensive range of potential uses, but over past ten years, interest in their usage as barrier layer or as reinforcements in coatings for corrosion prevention has developed. This review compiles the most recent information and seeks to provide authors with a broad synopsis of the most contemporary progresses in the application of GBMs in various anti-corrosion techniques.

Electrochemical and Molecular Dynamic Investigation of Some New Pyrimidine Derivatives as Corrosion Inhibitors for Aluminium in Acid Medium

A new class of corrosion inhibitors, namely, pyridine-2,6-diamine (PD) , pyrimidin-2-amine (PA), 6-amino-3,4-dihydropyrimidine-2(1H)-thione (ADT) and ethyl (R)-6-(4-chlorophenyl)-2-mercapto-4-methyl-1,6-dihydropyrimidine-5-carboxylate (EMMD) has been used. The influence of these pyridine-pyrimidine on the dissolution of aluminum in molar HCl has been investigated using impedance spectroscopy as well as potentiodynamic polarization and molecular dynamics simulations. Impedance spectroscopy data show that values of constant phase elements, CPE are decreased. Polarization resistance and protection efficiency increase with increasing concentration of pyridine-pyrimidine derivatives as the electric double layer increased. Electronic equivalent circuit of the investigated system is suggested. Potentiodynamic polarization results showed that these derivatives are mixed-type inhibitors with mainly cathodic action. Molecular simulations are used to simulate the adsorption of pyridine-pyrimidine, on the aluminum oxide substrate.

Grinding performance of hardened steel: a study about the application of different cutting fluids with corrosion inhibitor

The use of cutting fluid in the grinding process is crucial to guarantee quality in the products. However, most cutting fluids can cause disease to operators and damage the environment, which adds costs to the industry, as well as a deficit in the operator’s quality of life. In addition, the metalworking industry has as problem control corrosion in their parts; it demands to add the process of remove cutting fluid of the workpieces and add a protective oil on their surface. In this context, a new class of corrosion inhibitors that use water as a propagation medium, generically known as V-active® VCI, was formulated, which made it possible to develop, firstly, a cutting fluid with the addition of such inhibitor, called generically VCI 1, which would eliminate the process of degreasing and adding protective oil. Previous research has indicated the VCI 1 has an excellent performance in the grinding process, which promoted the development of two other new fluids (named generically VCI 2 and VCI EP) at a reduced market cost to make the product more competitive. In addition to the cost savings compared with the VCI 1, the VCI EP has the differential of an extreme pressure additive. It is noteworthy that the fluids in question pose no risk to humans and are biodegradable. Thus, the performance of these two new fluids with a corrosion inhibitor was verified in the grinding process of AISI 4340 steel with an aluminum oxide grinding wheel and the results were compared with the higher market cost V-active® VCI fluid and with a base fluid without the corrosion inhibitor. The comparison took place at three different feed rates (0.25, 0.50, and 0.75 mm/min). For each feed rate, the following were evaluated: surface roughness; roundness error, diametral grinding wheel wear, microhardness, optical microscopy, and acoustic emission, and the ground surface was analyzed using scanning electron microscopy (SEM). Therefore, useful information was obtained for the technological development of the rectification process, thus adding to scientific knowledge and dissemination of knowledge to society.

Synthesis of a new class of corrosion inhibitors derived from natural fatty acid: 13‐Docosenoic acid amide derivatives for oil and gas industry

As corrosion inhibitors, a series of new amide derivatives of 13‐docosenoic acid was synthesized in yields of above 90% by reacting 13-docosenoic acid with primary and secondary aliphatic and aromatic amines. The inhibition efficiencies (%IEs) of these compounds at various concentrations for the suppression of corrosion of mild steel in 1.00 M HCl exposed for 96 h (4 days) at temperatures in the range 298–333 K were measured via gravimetric corrosion measurements. At 100 ppm, all compounds yielded satisfactory corrosion %IE in 1.00 M HCl; compounds 2 and 7 exhibited remarkable %IE of 70.0 and 74.7%, respectively. The results of gravimetric measurements further revealed that compound 7 performed excellently at 60 °C, with %IE = 96.8 at 500 ppm. Quantum chemical density functional theory (DFT) calculations helped predict that compound 7 should have more aromatic character, enabling it to serve as a donor-center for the empty d-orbital of the metal atoms, leading to higher corrosion IE. The adsorption of the inhibitor molecules on the surface of mild steel followed the Langmuir adsorption model, and the free energy of adsorption (ΔGads) value indicated that the inhibitors are adsorbed through a combined physisorption and chemisorption mechanism to provide effective surface coverage.

Theoretical and experimental electronic spectra of neutral, monoprotonated and diprotonated dapsone

Dapsone has been receiving growing interest due to it use as a new class of corrosion inhibitors, forming copolymers with aniline, pyrrole, diphenylamine and 4-aminodiphenylamine. The present work focuses on characterizing the theoretical and experimental electronic spectra of the neutral, monoprotonated and diprotonated dapsone. The theoretical electronic spectrum was obtained through the excited state characterization via time-dependent DFT theory. NBO analysis was carried out to identify the molecular orbitals involved in the detected experimental UV bands. The detected absorption wavelength values for the neutral dapsone were 292 and 258 nm (experiment), and 286.9 and 251.7 nm (theoretical). Concerning the protonated dapsone species, it was observed that the absorbance values were strongly dependent on pH, especially at pH between 1.0 and 4.0. As the pH of the solution decreases, the experimental band at 292 nm slowly decreases and shifts to 290 nm, while the absorption at 258 nm decreases until it disappears, and a new absorption band arises at 240 nm. While, when the basicity increases, the absorption spectra of dapsone do not change, but a regular red shift is noticed, and it is continued even up to pH 14.0. The red-shifted spectra may be due to the formation of a monoanion and/or dianion, but the isosbestic points were not constant.

Study of corrosion inhibition of C38 steel in 1\xa0M HCl solution by polyethyleneiminemethylene phosphonic acid

A new class of corrosion inhibitors, namely, polyethyleneiminemethylene phosphonic acid (PEIMPA), was synthesized and its inhibiting action on the corrosion of C38 steel in 1 M HCl at 30 °C was investigated by various corrosion monitoring techniques such as weight loss measurements, potentiodynamic polarization, linear polarization resistance (Rp), and surface analysis (SEM and EDX) which are used to characterize the steel surface. Weight loss measurements revealed that the presence of PEIMPA increases the inhibition efficiency by decreasing the corrosion rate. Tafel polarization study showed that the inhibitor acts as a mixed-type inhibitor. Adsorption of PEIMPA on the carbon steel surface was found to obey the Langmuir isotherm. Some thermodynamic functions of dissolution and adsorption processes were also determined and discussed. The SEM results showed the formation of protective film on the mild steel surface in the presence of PEIMPA. The results obtained from different tested techniques were in good agreement.

Pyridine-based functionalized graphene oxides as a new class of corrosion inhibitors for mild steel: an experimental and DFT approach

Two functionalized graphene oxides, diazo pyridine functionalized graphene oxide and diamino pyridine functionalized graphene oxide, were synthesised and evaluated as corrosion inhibitors on mild steel in 1 M hydrochloric acid.

Dendrimers: A new class of corrosion inhibitors for mild steel in 1 M HCl: Experimental and quantum chemical studies

The inhibition properties of two ammonia cored dendrimers have been investigated for mild steel corrosion in 1M hydrochloric acid solution using chemical, electrochemical, surface and quantum chemical calculation methods. It was observed that inhibition efficiency increases with increasing the concentration of both the dendrimers and maximum efficiency was obtained at 50ppm (50mgL−1) concentration. Potentiodynamic study suggested that investigated dendrimers behaved as mixed inhibitors and their adsorption on mild steel surface obeyed the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) examinations of mild steel surface confirmed the inhibition behavior of investigated inhibitor molecules. Atomic force microscopic (AFM) study revealed that studied compounds increases the surface smoothness of AFM micrographs by adsorbing on the metallic surface. Several quantum chemical calculations parameters were calculated and the results obtained were found to be consistent with the experimental findings.

A Review on Environmentally-safe Corrosion deterrence of Metals in Various Media

<div><p><em>The present review gives a brief application of environmentally – safe corrosion inhibitors for various metals like aluminum, copper, mild steel, and zinc. Due to the enormous increase of industrial activities, a large amount of mineral acids are consumed. Therefore more number of metals gets corroded. These problems can be solved by using corrosion deterence. Although many chemical deterence are available most of them are highly virulent. So there is a need to explore a new class of corrosion inhibitors with good inhibition efficiency and that are environmentally - safe. Consequently, it can be achieved by using plant materials as corrosion inhibitors which are non-toxic, easily available and biodegradable.</em></p></div>

Studying Copper Electropolishing Inhibition in Presence of Some Organic Alcohols

Electro polishing is defined as anodic corrosion. The issue of the effects of corrosion on structural integrity of metal surfaces has been a question of concern for some time. The uses of chemical corrosion inhibitors are common in production and processing operations. Nevertheless, the challenge is to develop a new class of corrosion inhibitors to protect the materials, due to the economic importance of copper there are several researches deals with acceleration and inhibition of this process. In this paper the electropolishing process inhibited with different ratio by addition of some organic alcohols(methanol, ethanol,propanol, and isopropanol) by addition with concentration (2, 5, 10, 15, 20, 25 and 30 %) .The results reveal that these organic alcohols have a strongest inhibitive effect ranging from8. 7 – 53.8 % and the thermodynamic parameters were present.

The Inhibition of Mild Steel Corrosion in Sulfuric Acid by New Dapsone Derivatives

Dapsone derivatives Viz., 4, 4’-sulfonylbis(N-((1H-pyrrol-2-yl)methylene)aniline) (SBPMA) and 2-dimethylamino-5-[(4-{4-[(4-dimethylamino-benzylidene)-amino]-benzenesulfonyl}-phenylimino)-methyl]-benzene (DBBPB), a new class of corrosion inhibitors have been synthesized and their corrosion inhibition efficiency on mild steel in 0.5 M H2SO4 was investigated by mass loss, Tafel polarization and AC impedance measurements. Potentiodynamic polarization studies showed that, these compounds behave as mixed type of corrosion inhibitors. The adsorption process was found to obey Langmuir isotherm model. Electrochemical impedance spectroscopy (EIS) studies revealed that polarization resistance (RP) increases and double layer capacitance (Cdl) decreases as the concentration of the inhibitors increases. Various thermodynamic parameters for the adsorption of inhibitors on mild steel were computed and discussed. FTIR, EDX and SEM analyses were performed to study the film persistency of the inhibitors.

The water soluble composite poly(vinylpyrrolidone–methylaniline): A new class of corrosion inhibitors of mild steel in hydrochloric acid media

In recent years poly methyl aniline has been reported as one of the efficient corrosion inhibitors of mild steel in acidic media. In view of the major limitation of the insolubility of polymethyl aniline PMA, we propose to convert PMA into a water soluble composite using supporting polymer polyvinylpyrrolidone to get higher solubility and corrosion inhibition efficiency. The water soluble composite poly(vinylpyrrolidone-methyl aniline) was synthesized by chemical oxidative polymerization and its inhibitive effect on mild steel in 1M HCl has been investigated using weight loss and electrochemical techniques (potentiodynamic polarization studies and impedance spectroscopy). SEM and EDX analyses are carried out to establish a protective film formation on the metal surface.

Gemini surfactants: a new class of corrosion inhibitors for brass in 3N HNO3 solution

PurposeThe purpose of this paper is to present the results of some corrosion inhibition studies of brass in 3N HNO3 by gemini surfactants.Design/methodology/approachGemini surfactants namely: N‐trimethyl butane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (BEAB), N‐hexane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (HEAB), N‐dodecane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (DDEAB) and N‐hexadecane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (HDEAB) were synthesized in the laboratory and their influence has been investigated for controlling the dissolution of brass in 3N HNO3. Weight loss, potentiodynamic polarization and electrochemical impedance have been employed for the study. Weight loss experiments were performed as per standard method (ASTM, 1987). Potentiodynamic polarization studies were carried out using EG&G PARC potentiostat/galvanostat (model 173), universal programmer (model 175) and X‐Y recorder (model RE 0089) and impedance measurements were carried out with an EG&G PAR (model 5301 A) lock‐in‐amplifier, using an IBM computer.FindingsThe inhibition efficiency for all the gemini surfactants increases with increase in concentrations. The maximum inhibition efficiency of each inhibitor was achieved at 250 ppm concentration. The inhibition efficiency of all the inhibitors decreases on increasing the temperature from 30 to 50°C. The results of potentiodynamic polarization studies revealed that all the compounds were mixed type inhibitors and inhibit the corrosion of brass by blocking the active sites of the metal. The adsorption of the compounds on brass surface in 3N HNO3 has been found to obey the Langmuir adsorption isotherm.Originality/valueThe paper provides information regarding corrosion inhibition of brass in 3N HNO3, the mechanism of the inhibition on the basis of molecular structures of the inhibitors, activation energy and free energy of adsorption.

Cu(II), Co(II) and Ni(II) complexes of –Br and –OCH2CH3 substituted Schiff bases as corrosion inhibitors for aluminium in acidic media

A group of Cu(II), Ni(II) and Co(II) complexes of –Br and –OCH2CH3 substituted Schiff bases as a new class of corrosion inhibitors for aluminium has been studied in 0.1 M HCl by the addition of 10 ppm compound using potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization methods and gas evolution tests at 25 °C. The inhibition efficiencies obtained from all methods employed are in good agreement. Results show Ni(II) complex of –OCH2CH3 substituted Schiff bases was the best inhibitor with a mean efficiency of 69% at 10 ppm additive concentration. The potentiodynamic polarization curves showed both the cathodic and the anodic processes of aluminium corrosion were suppressed, and the Nyquist plots of impedance gave mainly a capacitive loop. Scanning electron microscopy (SEM) was done from the surface of the exposed sample indicating uniform film on the surface.

Bis-isoxazolidines: A new class of corrosion inhibitors of mild steel in acidic media

Two new bis-isoxazolidines were synthesized in excellent yields via cycloaddition reaction of 1-pyrroline 1-oxide with 2,7-di(10-undecenyloxy)naphthalene and 1,4-di(10-undecenyloxy)benzene. One of the bis-isoxazolidines, on reaction with two equivalents of 1-bromododecane, afforded a bis-quaternary ammonium salt. All three inhibitor molecules in the presence of 400 ppm at 60 °C achieved inhibition efficiencies (IE) in the ranges 97–98% and 92–96% as determined by gravimetric method for corrosion of mild steel in 1 M HCl and 0.5 M H 2SO 4, respectively. The results obtained by the electrochemical methods using Tafel plots and electrochemical impedance spectroscopy corroborated the findings of the weightloss method. Both bis-isoxazolidines demonstrated remarkable efficiency in the lower range of inhibitor concentrations – in the presence of a meager 1.5 ppm of the inhibitor molecules, IEs of ∼70% in 1 M HCl were achieved. Thermodynamic parameters ( Δ G ads 0 , Δ H ads 0 , Δ S ads 0 ) for the adsorption process in the presence of the bis-isoxazolidines were determined. The Δ G ads 0 values of around –90 kJ/mol in 1 M HCl and −50 kJ/mol in 0.5 M H 2SO 4, pointed towards the chemisorption of the inhibitor molecules, especially in HCl media. While the corrosion inhibition by these molecules was predominantly under cathodic control in 1 M HCl, the inhibition in 0.5 M H 2SO 4 was found to be under anodic control. The bis-isoxazolidines were found to provide a suitable inhibition mechanism for the corrosion inhibition in HCl as well as in H 2SO 4 media.

Cobalt(III) complexes of macrocyclic-bidentate type as a new group of corrosion inhibitors for iron in perchloric acid

A new class of corrosion inhibitors for iron demonstrated by group of cobalt complex compounds, of the general formula [Co III(Rdtc)cyclam](ClO 4) 2 ( 1)–( 4) where cyclam is 1,4,8,11-tetraazacyclotetradecane and Rdtc − refer to piperidine-, 2-, 3- or 4-methylpiperidine-dithiocarbamates, respectively, has been studied. Investigation of inhibiting properties of the ligands themselves as well as their corresponding complexes with Co(III) ion, was performed in 0.1 M HClO 4 by potentiodynamic polarization and EIS measurements. Cobalt complexes inhibit the corrosion of iron better than the uncomplexed ligands. Polarization curves suggest that complexes and amino-ligands are mixed-type and cathodic-type inhibitors, respectively. The impedance of the inhibited substrate increased with increasing concentration of inhibitor. An equivalent circuit is suggested, based on the analysis of EIS spectra. Using molecular modeling calculations, the complex compounds were characterized in terms of their structural properties and inhibition activity.

Calcium monofluorophosphate: a new class of corrosion inhibitors in NaCl medium

The effect of a new class of corrosion inhibitors, namely the monofluorophosphate of calcium, on the corrosion of iron, nickel, and copper in 3% NaCl solution has been investigated using potentiodynamic polarisation, measurement of open circuit potential, X-ray photoemission spectroscopy (XPS), and scanning electron microscope (SEM) techniques. The addition of an increasing concentration of calcium monofluorophosphate causes a shift of the corrosion potential in the positive direction, with a decrease of the anodic current density. The adsorption characteristics of this compound on the metal surface play a significant role in the inhibition process.

Calcium monofluorophosphate: a new class of corrosion inhibitors in NaCl medium

Calcium monofluorophosphate: a new class of corrosion inhibitors in NaCl medium

A corrosion inhibition study of iron by phosphonic acids in sodium chloride solution

The effect of a new class of corrosion inhibitors, namely piperidin-1-yl-phosphonic acid (PPA) and (4-phosphono-piperazin-1-yl) phosphonic acid (PPPA) on the corrosion of iron in NaCl medium has been investigated by electrochemical measurements. Potentiodynamic polarization studies clearly reveal the type of the inhibitor. The addition of increasing concentrations of phosphonic acids causes a shift of the pitting potential ( E pit) in the positive direction, indicating the inhibitive effect of the added phosphonic acid on the pitting attack. The potential of corrosion is moved towards negative values and the corrosion current is reduced. The values of the current are lower in the presence of PPA and PPPA. This is explained by the fact that most of the surface of the electrode is covered by the molecules adsorbed. PPPA has a strongly inhibitive effect on chloride pitting corrosion, it seems that the addition of the NCH 2PO 3H group (center adsorption) in the PPA para-position, giving PPPA, reinforces the active sites of this molecule and consequently increases its inhibition efficiency.