Corrosion is the major source of failures and leaks in the oil and gas industry. Internal corrosion has been the most notable contributing factor to pipeline failure. For an extended root cause analysis of the internal corrosion in gas pipelines, a transmission pipe wheel exhibiting significant corrosion scale build-up was taken down after more than 10 years of service. The present investigation aims to analyze the morphologies of the corrosion pits as well as the chemical compositions of the corrosion deposits within. The investigation was carried out by conducting standard failure analysis methods including visual examination, metallurgical examinations using optical microscopy in combination with scanning/transmission electron microscopy (SEM/TEM), thermal gravimetric analysis (TGA) and X-ray Powder Diffraction analysis (XRD). The results revealed that chlorine attack appears to be a major root cause of failure manifested by Akageneite scale build up and consequent tube loss. There is evidence that chlorine penetrated either through and/or underneath the sulfide protective film at the alloy- sulfide interface allowing chlorine ions to become in direct contact with alloy and thus consequent corrosion attack. Moreover, more chlorine and oxyhydroxides were found at the bottom of well close to the reservoir side (associated with moisture presence) suggesting chlorine containing reservoir water might be responsible for pitting and following severe corrosion. It was concluded that the presence of high concentration of chloride might be the main reason of the localized pits. This case study will shed light on root causes of chlorine attack followed with internal corrosion in gas production well.

Contact glow discharge electrolysis (CGDE) is a novel electrochemical phenomenon in which gas plasma is maintained by dc glow discharges between one of the electrodes and the surrounding electrolyte in a conventional electrolysis cell setup.The phenomenon develops either cathode/anode spontaneously in course of ordinary electrolysis whenever the voltage applied is sufficiently high. The transition from ordinary electrolysis to CGDE is marked by a significantly large drop in the current with simultaneous appearance of a luminous gaseous sheath over the cathode or the anode. CGDE can be observed in aqueous, man aqueous or molten electrolytes whenever the conditions for its formation are favorable. This novel electrolysis is an example of electrochemical processes across a plasma-electrolyte interface in contrast to a solid-electrolyte interface in conventional electrolysis. The chemical effects of CGDE are, not surprisingly, remarkably different from those of ordinary electrolysis. The products are novel for ordinary electrolysis and their yields exceed significantly the Faraday law values. The phenomenon has been reported in the literature off and on since its first reporting in 1844, and described by various terms such as anode effect, aqueous anode effect electrode effect, glow electrolysis galvanoluminescence, electrode glow besides contact glow discharge electrolysis.

A closely related phenomenon where electrochemical processes too occur at a plasma electrolyte interface is ‘glow discharge electrolysis (GDE)’. As compared to CGDE, GDE has been investigated much more extensively. In this technique, one of the electrodes (called the gas plasma electrode) usually the anode is placed above the liquid electrolyte and a glow discharge is passed from the electrode to the surface of the electrolyte. It is distinguished from CGDE in that one of the electrodes is located in the gas space in contrast to that both the electrodes are dipped into the liquid electrolyte during CGDE. However, there are interesting similarities in the chemical effects of CGDE and GDE. The Products obtained at the glow discharge electrode in either phenomenon are novel for normal electrolysis and the yields are remarkably deviated from those stipulated by Faraday’s laws. Different aspects of CGDE have drawn the attention of many investigators. Origin, chemical effects, spectroscopy of light emission is the principal aspects of investigation. CGDE is a potential tool for generating OH radical, H radicals, metallic nano-particles and heat treatment of metal useful for dental implants.

Ionic liquids (ILs) and deep eutectic solvents (DESs) are gaining prominence as next-generation solvents in solution chemistry, offering a unique combination of tunable structures, negligible vapor pressure, and exceptional thermal and chemical stability. These properties, along with their superior solvating power and ionic conductivity, position them as ideal candidates for advancing sustainable separation and extraction technologies.

This talk will explore how the molecular-level tailoring of ILs and DESs can be leveraged to optimize their physico-chemical properties for enhanced performance in sorption and extraction processes. Case studies will highlight their effectiveness in critical applications such as wastewater treatment, selective metal recovery from electronic waste and spent lithium-ion batteries, and biomass valorization.

Particular attention will be given to their environmental advantages over conventional solvents, including reduced toxicity, reusability, and compliance with green chemistry and circular economy principles. By examining recent advances and emerging trends, this presentation aims to illuminate the transformative potential of ILs and DESs in driving sustainable innovation across chemical industries.

Titanium alloys are widely used as aerospace structural materials because of their low density, high strength and excellent corrosion resistance at low-to-moderate temperatures. However, when the working temperature is over 400°C, titanium alloys usually show a poor oxidation resistance because of the fast diffusion of oxygen through the nascent TiO_2–X surface oxide layer[1]. On the other hand, SiO₂ shows considerable promise as a protective oxide layer, for both high temperature oxidation corrosion; however, the most successful application so far of Si–based oxides to Ti–alloys is the preprocessed amorphous (or ‘enamel’) SiO₂ coating [2]. Ti–based Multi-Principal Element Alloys with added Si potentially provide a novel opportunity to find new alloy compositions which could form an SiO₂–based layer spontaneously at elevated temperatures [3]. Boron has also been suggested as a further alloying addition, that could avoid the possible issue of pesting of formed silicide compounds in such MPEAs at intermediate temperatures [4].

This research builds an equimolar TiCrAlNb MPEA alloy system with different ratios of Si and/or B content and characterizes their microstructure, before and after oxidation, to study the influence of the addition of silicon and boron. The oxidation resistance of such alloys shows in general a significant improvement compared with a typical Ti-6Al-4V Ti–alloy. Furthermore, Niobium shows a higher tendency to form compounds with silicon/boron. In addition to such silicide/boride compounds, some laves phases were also observed and the addition of silicon showed a significant influence on the microstructure, the addition of B refines the lamellar microstructure while the addition of Si transfers the structure into an equiaxed dendritic structure.
 

Corrosion is a natural phenomenon that degrades the properties of materials when they are exposed to environmental elements. This issue is especially prevalent in steel structures, where it can result in substantial economic losses, structural failures, and even pose risks to human safety. The corrosion of steel can be triggered by various factors, including environmental conditions, mechanical stress, and the presence of impurities. This study investigates the macroscopic corrosion of steel under potentiostatic conditions through a combination of electrochemical experiments and probabilistic modeling. A probabilistic cellular automata (PCA) model was developed in MATLAB to predict the propagation and penetration of corrosive material in steel. The model was refined using experimental data obtained from a three-electrode corrosion cell. Various steel specimens were subjected to corrosion under different environmental conditions, and their mechanical strengths were assessed. The refined model's predictions were validated using finite element analysis (FEA) and tensile testing of the corroded specimens. The FEA results showed a strong correlation with the tensile testing outcomes across three different specimen designs. This thesis enhances the understanding of steel corrosion under potentiostatic conditions and offers a predictive tool for assessing the corrosion behavior and mechanical properties of steel in such environments.