T. Shahrabi, Hossein Tavakholi and M.G. Hosseini
In this paper, the main aim is to study the influence of some nitrogen heterocyclic compounds, namely 2‐mercaptobenzimidazole (2‐MBI), 2‐mercaptobenzoxazole (2‐MBO) and…
Abstract
Purpose
In this paper, the main aim is to study the influence of some nitrogen heterocyclic compounds, namely 2‐mercaptobenzimidazole (2‐MBI), 2‐mercaptobenzoxazole (2‐MBO) and 2‐mercaptobenzothiazole (2‐MBT) on the corrosion inhibition of copper in 0.5 M sulphuric acid.
Design/methodology/approach
Measurements were carried out in a three‐electrode cell that was connected to the corrosion measurement system using software for Tafel polarization. Impedance measurements were carried out at open circuit potential using an electrochemical interface and frequency response analyzer at frequencies from 100 kHz to 10 MHz.
Findings
For all the compounds, a consistent trend of increase in inhibition efficiency was observed as a function of concentration. The adsorption of all the compounds on to the copper surface in the acidic solution was found to obey the Langmuir Adsorption Isotherm. The values of activation energy and free energy of adsorption for all the compounds also were calculated. The Tafel polarization studies indicated that all the compounds were mixed inhibitors.
Research limitations/implications
In order to further the performance of heterocyclic compounds and also to identify their synergistic effects with some additives (such as surfactants) it is suggested that further research into the behaviour of these heterocyclic compounds with other metals be carried out.
Originality/value
The results of this paper can be used for acid descaling of copper in which suitable inhibitor systems with the highest efficiencies are required.
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Morteza Hoseinieh, Taghi Shahrabi, Morteza Farrokhi Rad and Bahram Ramezanzadeh
The aim of this paper is to investigate the influence of sour crude oil contaminant on the calcareous scale deposition under cathodic protection of carbon steel in artificial…
Abstract
Purpose
The aim of this paper is to investigate the influence of sour crude oil contaminant on the calcareous scale deposition under cathodic protection of carbon steel in artificial seawater.
Design/methodology/approach
Electrochemical and surface characterizations are carried out using chronoamperometry, electrochemical impedance spectroscopy, scanning electron microscope/energy dispersive spectroscopy, X-Ray diffraction and Raman spectroscopy techniques.
Findings
Results showed that sour oil limited the deposit nucleation regarding its volume concentrations. The inhibition mechanism was examined to be simultaneous acts of pH reduction and mackinawite formation beside minor physical adsorption of oil molecules on steel electrode.
Originality/value
There is no paper concerning the proposed subject, and the idea of this work is fully novel which is of great significance because of the consequences of disastrous oil spill phenomena on the integrity of exposed offshore facilities in terms of optimum protection against probable corrosion mechanisms.
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K. Jafarzadeh, T. Shahrabi and S.M.M. Hadavi
The sulphidation behaviour of high contraction (HC) and low contraction (LC) chromium plated steel was studied in sulphur with a partial pressure of 1 atm at 1, 3, 5 and 7 h and…
Abstract
The sulphidation behaviour of high contraction (HC) and low contraction (LC) chromium plated steel was studied in sulphur with a partial pressure of 1 atm at 1, 3, 5 and 7 h and 0.1 and 0.01 atm at 5 h. The temperature was 600°C throughout the work. It was found that HC and LC chromium plating imparted significant sulphidation resistance to steel. It should be mentioned that by increasing sulphidation time and sulphur partial pressure, the hardness of chromium coating decreased. LC chromium coating had a lower thermal shock resistance than the HC coating. Thus, it was concluded that the HC chromium coating had the better sulphidation resistance.
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M. Ebrahimi mehr, T. Shahrabi and M.G. Hosseini
The inhibition effects of sodium silicate and polyphosphate on corrosion of carbon steel in a potable water supply have been studied using weight loss, electrochemical impedance…
Abstract
The inhibition effects of sodium silicate and polyphosphate on corrosion of carbon steel in a potable water supply have been studied using weight loss, electrochemical impedance and Tafel polarization measurements. In the water supply under test there were sufficient calcium ions, (220 ppm), to form the normal polyphosphates salts, which is a requisite for good protection. It was concluded that the inhibition efficiency of polyphosphate was higher than that of silicate. The synergistic inhibition effects of polyphosphate on the inhibition of silicate were studied. The results illustrated that silicates and polyphosphates can be useful as corrosion inhibitors for reducing the corrosion of carbon steel in potable water supply distribution systems. The optimal concentration for silicate alone was determined to be 11 ppm and for polyphosphate alone was 8 ppm. The optimum ratio of concentration for sodium silicate to sodium polyphosphate was 4 : 3.
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K. Jafarzadeh, T. Shahrabi, S.M.M. Hadavi and M.G. Hosseini
The paper aims to focus on the recognition of corrosion product morphologies of AA5083‐H321 corroding aluminum‐magnesium alloys used in the manufacture of aluminum high speed…
Abstract
Purpose
The paper aims to focus on the recognition of corrosion product morphologies of AA5083‐H321 corroding aluminum‐magnesium alloys used in the manufacture of aluminum high speed boats and submarines during flow induced corrosion in seawater.
Design/methodology/approach
All experiments were conducted in a 3.5 percent NaCl solution as the simulated marine environment. Hydrodynamic conditions were created by an rotating cylinder electrode (RCE) system. Morphological characterization of the surface was undertaken using SEM and EDAX techniques. Cyclic polarization tests were used to determine the electrochemical behavior of the alloy.
Findings
The results obtained reveal that the pit density on the sample surface increased with increasing the rotation speed. The enhanced flow condition also enhanced the tendency for intermetallic particles, including submicron size Al(Mg,Mn) inclusions, to promote pitting corrosion of the alloy. An interesting result was that crystallographic pitting occurred at rotation speeds greater than 5 m/s.
Practical implications
In the selection of corrosion control methods for high speed aluminum‐hulled boats, control of erosion corrosion was determined to be more important than any other form of corrosion.
Originality/value
Provides information about the contribution of mechanical and electrochemical corrosion phenomena in corrosion of high speed aluminum boats under hydrodynamic conditions. Characterization of new intermetallic particles in aluminum‐magnesium alloys that can promote pitting during flow induced corrosion in marine environments. Provides new information about the origin of crystallographic pitting attack on aluminum.
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Masoud Rezaei Saman Kandi, Taghi Shahrabi, Saed Reza Allahkaram and Mir Javad Geramian
Electrical industry equipment in the southern parts of Iran have sustained severe damages as a result of corrosive soil containing different kinds of salt, in combination with the…
Abstract
Electrical industry equipment in the southern parts of Iran have sustained severe damages as a result of corrosive soil containing different kinds of salt, in combination with the corrosive local atmosphere. The present paper is the result of investigations into the behaviour of coatings for various electrical insulators end‐fittings. In this research, the performance of Al‐Zn alloy coating was compared to conventional galvanized zinc coatings by means of atmospheric corrosion tests. The results demonstrated the higher corrosion resistance of the alloy coatings, compared to that of conventional galvanized coatings. Insulator end‐fittings generally are made of steel, which are coated with a hot‐dip galvanized coating. The combination of Al and Zn elements in this coating was demonstrated to possess better galvanic protection and lower corrosion rate than did pure zinc.
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Mobin Salasi, Taghi Shahrabi and Emad Roayaei
To study and compare the inhibition effects of eco‐friendly inhibitors of sodium silicate and 1‐hydroxyethylidene 1,1 diphosphonic acid (HEDP) in corrosion control and prevention…
Abstract
Purpose
To study and compare the inhibition effects of eco‐friendly inhibitors of sodium silicate and 1‐hydroxyethylidene 1,1 diphosphonic acid (HEDP) in corrosion control and prevention of soft water discolouration (red water) in carbon steel pipelines.
Design/methodology/approach
Electrochemical impedance and Tafel polarization measurements were used to study corrosion inhibition properties. The experiments were carried out under different concentration ratios of inhibitors. Different hydrodynamic conditions were applied to simulate pipeline fluid flow. Scanning electron microscopy (SEM) and EDAX analysis were used for surface studies.
Findings
It was observed that corrosion inhibitor combinations under static conditions showed synergistic effects at low concentrations. The inhibition efficiency and synergistic behaviours of inhibitors were enhanced as the electrolyte turbulence was increased. In addition, the inhibitor concentration value required to reach maximum inhibition decreased. It was found that at 20 ppm sodium silicate and 5 ppm HEDP, co‐inhibition efficiencies increased significantly to more than 90 per cent and the corrosion rate decreased far below 1 mpy as the electrode rotational speed was increased. Surface studies using SEM revealed the formation of a compact and uniform film of co‐inhibitors.
Practical implications
The results of this paper can be used for the development of effective, non‐toxic and economically attractive corrosion inhibitor formulations for soft water transmission pipelines.
Originality/value
The observed synergistic behaviour can be due to the incorporation of the silicate gel‐like network through organic phosphorous bonds. The hydrodynamic condition of the electrolyte leads to enhancement of inhibition efficiency, which indicates that the corrosion inhibition was mass transfer controlled.
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Ehsan Saebnoori, Taghi Shahrabi, Alireza Sabour Rouhaghdam and Majid Jafarian
The purpose of this paper is to investigate the effect of thermal treatment at low partial pressure of oxygen on electrochemical corrosion resistance of Ti‐47Al‐2Cr (at %…
Abstract
Purpose
The purpose of this paper is to investigate the effect of thermal treatment at low partial pressure of oxygen on electrochemical corrosion resistance of Ti‐47Al‐2Cr (at %) intermetallic, known as γ‐TiAl alloy.
Design/methodology/approach
The surfaces of the samples were modified by thermal treatment at different temperatures in N2 gas flow for an hour. Characterization of the modified surface layers was carried out by microscopic examinations, hardness and roughness tests, and X‐ray diffraction analyses. Potentiodynamic polarization was used to evaluate the corrosion performance of γ‐TiAl in Ringer's solution.
Findings
The results indicated that the alloy treated at 950 °C had the optimum corrosion resistance, which can be attributed to the formation of an oxide layer by the surface thermal treatment and increase of the passive layer thickness.
Practical implications
Low corrosion rate (CR), high pitting potential (Epit), and more noble corrosion potential (Ecorr) make it possible for γ‐TiAl to be considered as a candidate for biomedical applications.
Originality/value
The treatment described in the paper is a novel method for surface modification of this type of alloy and results showed that it was an effective treatment and that the corrosion resistance improved remarkably.
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Mohsin Shahzad, Ying Qu, Abaid Ullah Zafar, Saif Ur Rehman and Tahir Islam
Enhancing green innovation for corporate sustainability is one of the recent issues globally. Knowledge management has been determined as a core factor that hamstrings green…
Abstract
Purpose
Enhancing green innovation for corporate sustainability is one of the recent issues globally. Knowledge management has been determined as a core factor that hamstrings green innovation. The existing literature was limited to expose the importance of the knowledge management process for corporate sustainable performance. Thus, this paper aims to examine the role of the knowledge management process for corporate sustainable performance with the integration of green innovation and organizational agility following the resource-based view theory.
Design/methodology/approach
Cross-sectional design was used in this study. Data were gathered through convenience sampling from 475 respondents of multinational manufacturing corporations of Pakistan, analyzed by using structural equation modeling.
Findings
This study revealed that the knowledge management process and its all constructs (acquisition, dissemination and application) lead toward green innovation; further, green innovation influences corporate sustainable performance and its all constructs (environment, economic and social). Green innovation partially mediates the association between the knowledge management process and corporate sustainable performance. Besides, organizational agility has a positive effect on green innovation and corporate sustainable performance but was not found moderating these relations. The study educates that organizations investing in innovative technologies and adopting greener strategies are not only adequate for achieving sustainable performance, soft issues such as knowledge management and organizational agility but also important factors in the current knowledge base economy.
Originality/value
This study is an attempt to examine the previously undiscovered multi-dimensional relationships among the knowledge management process, green innovation, organizational agility and corporate sustainable performance. The presence of a positive correlation among these constructs was observed, proving the conceptual framework for this study.
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Chhotu Ram, Chhaya Sharma and A K Singh
– This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels.
Abstract
Purpose
This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels.
Design/methodology/approach
For this purpose, immersion test and electrochemical polarization tests were conducted in mill and synthetic effluent to evaluate the uniform and localized corrosion.
Findings
Corrosivity of mill effluent has been compared with synthetic and primary-stage effluent of the same mill. It is observed that anions present in them, viz. SO4−, PO34−, NO2− and NO3−, impart inhibition, whereas Cl− and chlorophenols enhance the corrosivity of the effluent. The overall effect of various components was reduction in corrosivity of secondary mill effluent.
Originality/value
These observations can be useful for material selection and helpful in corrosion mitigation in paper mill effluent treatment plants.