Effect of Polar Extract of Cocoa Peels Inhibitor on Mechanical Properties and Microstructure of Mild Steel Exposed in Hydrocloric Acid

2015 ◽  
Vol 776 ◽  
pp. 193-200 ◽  
Author(s):  
Gunawarman ◽  
Yuli Yetri ◽  
Emriadi ◽  
Novesar Jamarun ◽  
Ken-Cho ◽  
...  

Effect of addition of theobroma cacao peels extract (TCPE), a new proposed green inhibitor, on tensile and hardness properties, and related microstructure of mild steel exposed in solution of 1.5M HCl was investigated in order to know the contribution of this kind of inhibitor in controlling mechanical properties, in addition to reducing corrosion attack. Corrosion behaviors including inhibition mechanism and adsorption process during exposure were then discussed. Corrosion rate and inhibitory efficiency of mild steel samples containing 0.3%C were determined using weight loss method. The samples were exposed in the acid solution with and without addition of 0.5-2.5% the TCPE. Tensile and hardness tests were subsequently performed on the samples to determine the change of mechanical properties of the metal prior and after addition of the extracts. Sample surface morphologies and chemical composition as well were observed by a scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDX). The results show that the strength, hardness and elongation of mild steel drop significantly due to heavy damage in the surface after immersion in the HCl solution for 32 days. However, these mechanical properties gradually increase with increasing concentration of the extract following the increase of surface coverage and inhibition efficiency. The increase of the tensile properties and hardness is due mainly to the ability of the inhibitor to cover mild steel surface through formation of metal-organo complexes protection layer in the surface of the mild steel. Although total carbon level in the surface of the mild steel also increases significantly, there is no any proof of carbon difussion into the mild steel. The addition of polar extract of theobroma cacao peels into a solution of 1.5 M HCl is, therefore, not only effective to minimize the degradation on the mild steel surface, but it also diminishes the mechanical properties reduction of the mild steel.

2015 ◽  
Vol 44 (6) ◽  
pp. 371-378 ◽  
Author(s):  
Y. Sangeetha ◽  
S. Meenakshi ◽  
C. Sairam Sundaram

Purpose – The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl. Design/methodology/approach – A pharmaceutical drug acetyl G was investigated for its corrosion inhibition efficiency using weight loss method, potentiodynamic polarisation and electrochemical impedance spectroscopy. Findings – The inhibition efficiency increased with increase in inhibitor concentration. Results from polarisation studies revealed mixed type of inhibition. Impedance studies, scanning electron microscopy and Fourier transform spectroscopy confirm the adsorption of inhibitor on the mild steel surface. Research limitations/implications – The drug acetyl G has sulphur and nitrogen atoms which effectively block the corrosion of mild steel and is non-toxic and has good inhibition efficiency. Practical implications – This method provides an excellent, non-toxic and cost-effective material as a corrosion inhibitor for mild steel in acid medium. Originality/value – Application of this drug as a corrosion inhibitor has not been reported yet in the literature. Replacing the organic inhibitors, this green inhibitor shows excellent inhibition efficiency. This is adsorbed excellently on the mild steel surface due to the presence of long chain and hetero atoms. Thus, the drug retards the corrosion reaction.


Author(s):  
Khaoula Alaoui ◽  
Ashraf Abousalem ◽  
Burak Tüzün ◽  
Younes El Kacimi

This chapter describes some recent good works in the field of metallic corrosion monitoring using Triazepine carboxylate inhibitors in hydrochloric acidic media. The different sections of this chapter cover electrochemical measurements and theoretical investigations. This review reveals Triazepine carboxylate compounds as very good inhibitors for mild steel in hydrochloric medium. The inhibition action of all Triazepine carboxylates compound studied was performed via adsorption on mild steel surface. Comparison between several adsorption isotherms reveal that the adsorption was spontaneous and followed Langmuir isotherm in HCl for all inhibitors and all studied temperatures. Kinetic and thermodynamic parameters for all inhibitors led to suggest the occurrence of chemical mechanism and also the spontaneity of the adsorption process on mild steel surface. The corrosion inhibition mechanism was also compared and discussed with the light of some Triazepine carboxyale compounds constituents.


Author(s):  
Akindele Okewale ◽  
Felix Omoruwuo

The influence of neem leaf extract on corrosion inhibition of mild steel in 0.1 M HCl solution was studied using the weight loss method. Neem leaf extract which contains the double bond, carbonyl groups, and aromatic rings functional group as shown by the GCMS, phytochemical test, and FTIR analyses is one of the good natural plant extract that can be used as corrosion inhibitor. The weight loss on surface of mild steel at various inhibitor concentrations was determined. The highest inhibition efficiency of 93.24% was achieved using the neem leaf extract as corrosion inhibitor. Adsorption mechanism was investigated using Langmuir, Temkin, and Freundlich isotherms. Inhibitor adherence on the mild steel surface was spontaneous with the negative Gibb’s free energy value obtained. The mixed type adsorption mechanism (physisorption and chemisorption) is proposed for the inhibitor adsorption on mild steel surface. The inhibitor was adsorbed on the mild steel surface through adsorption of the phytochemical components on the surface of mild steel which protects the metal surface from corroding. The corrosion rate decreases from 0.001 to 0.0002MPY with increase in inhibitor concentrations and exposure time.


Author(s):  
Nyirimbibi Daniela Kalisa ◽  
Theonestea Muhizi ◽  
Jean Jacques Yvesa Niyotwizera ◽  
Jean Baptistea Barutwanayo ◽  
Jean Boscoa Nkuranga

In this study, the use of green corrosion inhibitors extracted from coffee husks was investigated on mild steel materials in acidic medium. Phenolic compounds from coffee husks were extracted using acetone solvent, characterised and investigated for their corrosion inhibiting properties. The FTIR and 1H-NMR technique were carried out to characterise the present phenolic compounds extracted from purified coffee husks. The corrosion inhibition efficiency of phenolic compounds from coffee husks extract on mild steel in 1.0 M HCl was evaluated by using weight loss method. The obtained results showed that corrosion rates decreased with the increase of inhibitor concentration, temperature and immersion time. The  optimum inhibition efficiency of 86.5% at 25 ºC was obtained with a concentration of 400 mg/L (400 ppm) of coffee husks extract in two hours of experiment. The observed inhibition efficiency was attributed to the physical adsorption mechanism of phenolic compounds on mild steel surface through charged ion formation from protonation of lone pairs of oxygen in phenol or ionic dissociation of carboxylic acid functional group that formed a charged layer over mild steel surface. Furthermore, it was pointed out that the adsorption process obeyed the Langmuir adsorption  isotherm model at all investigated temperatures between 25 and 40 ºC. Keywords: Corrosion inhibitor, phenolic compounds, coffee husks extract, mild steel, adsorption


Author(s):  
Inemesit A. Akpan ◽  
Okon U. Abakedi ◽  
Mfon A. James

Telfairia occidentalis rind extract has been studied as a potential green inhibitor for mild steel corrosion in 1 M H2SO4 using weight loss and hydrogen evolution methods. The results of the investigation reveal that Telfairia occidentalis rind extract is a good inhibitor of mild steel corrosion in sulphuric acid solution. The inhibition efficiency increases with increase in rind extract concentration but decreases with increase in temperature. The calculated thermodynamic parameters reveal that the corrosion inhibition process was endothermic and spontaneous. Physical adsorption has been proposed for the adsorption of Telfairia occidentalis rind extract onto mild steel surface. The adsorption of the extract on mild steel surface obeys the Langmuir adsorption isotherm. 


2009 ◽  
Vol 16 (06) ◽  
pp. 845-853 ◽  
Author(s):  
MUTHU NADAR LAVANYA ◽  
DEVARAYAN KESAVAN ◽  
NAGARAJAN PRABHAVATHI ◽  
NAGARAJAN SULOCHANA

The corrosion inhibition effect of 3-hydroxyflavone was studied on mild steel in 1 M hydrochloric acid ( HCl ). The anticorrosive effect was evaluated by weight loss and electrochemical methods which include Tafel polarization and AC impedance studies at 300 K. In weight loss method, the inhibition efficiency increased with increase in inhibitor concentration, and decreased with increase in temperature and immersion time, and acid concentration. The inhibitor showed maximum efficiency of 91% at 4 × 10-4 M concentration in 1 M hydrochloric acid. The Tafel polarization study showed that the inhibitor behaves likely as cathodic type. The corrosion inhibition effect measured by weight loss method and electrochemical studies was in good agreement with each other. The surface analysis was done by using scanning electron microscope (SEM). Several adsorption isotherms are assessed to study the adsorption behavior of the inhibitor on the mild steel surface. The negative value of ΔG ads indicates the spontaneous adsorption of the inhibitor on mild steel surface.


2021 ◽  
Vol 317 ◽  
pp. 498-505
Author(s):  
Sabrina M. Yahaya ◽  
Mohamad Kamal Harun ◽  
Ismaliza Ismail ◽  
Rosmamuhamadani Ramli

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.


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