Mokhtar Che Ismail

Reviews on Corrosion Inhibitors: A Short View

A range of numerous corrosion inhibitors, viz. organic molecules with hetero atoms and π-electron clouds, inorganic salts and plant excerpts likewise their corresponding phytoconstituents were reported with success for metals in different corrosive media. Various literature reviews related to corrosion inhibitors have been reported by many authors based on their application, classification, and inhibition mechanism. A short view of all these reviews is summarized in this manuscript. Various aspects of corrosion inhibitors as well as their recent trends and advancement are also discussed.

Effects of sulphide ion on corrosion behaviour of X52 steel in simulated solution containing metabolic products species: a study pertaining to microbiologically influenced corrosion (MIC)

Abstract The objective of this work is to study the effect of sulphide ion on the corrosion behaviour of X52 steel in the simulated solution containing sulphate reducing bacteria metabolic products species. Linear polarisation resistance and electrochemical impedance spectroscopy results show that the addition of 50 ppm sulphide ions increased the rate of X52 steel corrosion. However, with addition of 200 and 400 ppm sulphide, the corrosion rate decreased. The increase in corrosion rate is due to the increase in the cathodic reaction in the presence of sulphide, while the corrosion protection was related to FeS film formed, typically mackinawite and pyrite.

Corrosion behaviour of X52 steel in the presence of sulphite

Purpose – The purpose of this work was to study the corrosion behaviour of X52 steel in the presence of sulphite. Design/methodology/approach – The study was conducted in abiotic solutions containing species typical of sulphate-reducing bacteria (SRB) metabolism. Electrochemical techniques, i.e. linear polarization resistance (LPR), potentiodynamic and electrochemical impedance spectroscopy (EIS), were used to observe the corrosion kinetics and mechanism of X52 steel in the solution containing sulphite. Field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the corrosion products. Findings – LPR and EIS results showed that the addition of sulphite ions to the abiotic solutions increased the rate of X52 steel corrosion. The increase of corrosion rate was due to the increase in the cathodic reaction in the presence of sulphite. It was also observed that sulphite thinned the protective FeS film and caused corrosive species to adsorb on the sur...

Microstructure and Nanoindentation Characterization of Low Temperature Hybrid Treated layer on Austenitic Stainless Steel

In this work, the hybrid treated layer on austenitic AISI 316L stainless steels were characterized to investigate the improvement on its surface properties. Characterization of this resulting layer was performed by FESEM (Field Emission Scanning Electron Microscope), USPM (Universal Scanning Probe Microscope) and nanoindentation. By using these methods, changes in the mechanical properties due to the diffusion of carbon and nitrogen at low temperature treatments have been traced. This hybrid treated sample has confirmed a considerable increase in hardness and a small rise in the elastic modulus compared to the untreated sample. It is found that all treated samples have enhance E/H ratio which exhibited the decreasing tendency to plastic deformation and reduced the mismatch of properties, while keeping deformation within the elastic range.

Low Temperature Thermochemical Treatments of Austenitic Stainless Steel Without Impairing Its Corrosion Resistance

Austenitic stainless steel (ASS) is used applied widely owing to its very good corrosion resistance. However, the application of this material as a bearing surface is severely limited by very poor wear and friction behaviour. Consequently, Surface Engineering treatments for austenitic stainless steel are an interesting alternative way to increase the surface hardness and improve the wear resistance. For the purpose of this works, the Surface Engineering design will be classified, very broadly, into three groups : (a) those which coat the substrate: PVD, CVD, etc, (b) those which modify only the structure of the substrate, (c) those which modify the chemical composition and the structure of the substrate: thermochemical, ion implantation, plasma, etc. It is nowadays widely accepted that hard, wear and corrosion resistant surface layers can be produced on ASS by means low temperature nitriding and/or carburizing in a number of different media (salt bath,gas or plasma), each medium having its own strengths and weaknesses. In order to retain the corrosion resistance of austenitic stainless steel, these processes are typically conducted at temperatures below 450oC and 500oC, for nitriding and carburizing respectively. The result is a layer of precipitation free austenite, supersaturated with nitrogen and/or carbon, which is usually referred to as Sphase or expanded austenite.

Efficient Entrapment of Oxirane Ring Containing Compounds in Thermally Stable Poly(urea-formaldehyde) Polymer Shell Wall

This article aims to address the problems associated with the encapsulation of oxirane ring containing compounds in poly(urea-formaldehyde) (PUF) shell for application in self-healing composite systems. The main objectives were to produce non-agglomerated, stable microcapsules, and to control the pH drop during the encapsulation via oil-in-water emulsion polymerization. In the modified method; two stage additions of urea and formaldehyde monomers, core to shell ratio, weight percent and combination of two surfactants/emulsifiers were altered to produce the desired product. Analysis was done with optical microscope (OM), scanning electron microscopy (SEM), FTIR, particle size analyzer, and thermogravimetric analysis (TGA). The pH drop was confirmed by using a common epoxy resin, an epoxy functionalized polydimethylsiloxane (E-PDMS), and epoxidized palm oil (EPO) as cores. The modified oil-in-water emulsion polymerization of PUF was effective in preventing the pH drop during the encapsulation and a product stable for more than 3 months with less agglomeration was produced. The method produced microcapsules having diameters less than 100 μm at lower agitation rates. The modified method is only applicable to epoxy resin and not for compounds like amine hardeners. The use of stable microcapsules in self-healing coatings can lead towards cost reduction implied for repair and maintenance purposes.

Examination and Improvement of Salama Model for Calculation of Sand Erosion in Elbows

Sand erosion is a problem recognized in many facilities and piping components used in production, treatment, and transportation of oil and gas. Proper controlling of sand erosion requires early prediction at different conditions and within various ranges of flow parameters. Numerous models and correlations are available for sand erosion prediction in varies components. The applicability and accuracy of the available models depends on many factors such as the range of conditions and the number of parameters that are taken into account in developing the model. One of the models widely used for sand erosion prediction is Salama model, which is used for calculation of sand erosion in elbows and tees. In spite of Salama model’s simplicity, it is not recommended to use in many cases due to decrease in accuracy. Salama model accuracy, in general, decreases when it is applied to viscous fluids flow and low gas–liquid-ratio multiphase flow. In this paper, the discrepancy of Salama model with field data was confirmed by comparing its output with published measured data. The model was, then, improved by comparing its results with three sets of measured sand erosion data for pure gas, high gas–liquid-ratio fluids, and low gas–liquid-ratio fluids. The model improvement results in three models for prediction of sand erosion in elbows with higher accuracy.

Formation of Nano-Scale FeCO 3 Protective Corrosion Product in Carbon Dioxide-Saturated 3% Sodium Chloride Solution

Corrosion of carbon steel in CO2 saturated NaCl solution contains the formation of FeCO3, as a corrosion product. The protective property of the formed FeCO3 scale layer to corrosion in brine solutions containing CO2 was established as the possible cause of the corrosion rate decrease above 60 °C. In this study, formation of nanoscale FeCO3 film as a corrosion product of X52 carbon steel in CO2-Saturated 3% NaCl solution was investigated. Result showed that corrosion rate decreased after precipitation and formation of protective FeCO3 film in high temperature and high bulk solution pH.

Development of iridium oxide sensor for surface pH measurement of a corroding metal under deposit

1 Department of Physics, Shahid Beheshti University, Evin, Tehran 19839, Iran 2 Centre for Corrosion Research, Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Tronoh31750, Malaysia 3 Centre of Nanoscience and Nanotechnology (NANO-SciTech Centre), Institute of Science, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia * E-mail: skakooei59@hotmail.com, saeid.kakooei@utp.edu.my

Surface characteristics of low temperature hybrid thermochemical treatment of AISI 316L

This investigation proposed the low temperature thermochemical treatments in conventional tube furnace of hybrid treating which introduces nitrogen and carbon simultaneously with the aim to improve surface properties of AISI 316L. The outcome of the work showed the formation expanded austenite structured which is supersaturated with nitrogen and carbon. This structure is responsible to the higher hardness as well as better wear property without impairing its corrosion resistance. Characterization of this expanded austenite layers were performed including FESEM, USPM and elemental analysis to reveal the characters of the produced thin layers. Elemental profile of nitrogen and carbon across the hybrid treated layer were obtained by EDS-SEM. The results also demonstrate that hybrid treatment produces a thicker and unique layer on higher temperature treatments for 450°C without impairing its corrosion resistance according to the absence of nitride and carbide of treated layers.