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Copper (Cu) electrodeposition on ruthenium (Ru) oxides was studied due to important implications in semiconductor industry. Ruthenium, proposed as the copper diffusion barrier/liner material, has higher oxygen affinity to form different oxides. Three different oxides (the native oxide, reversible oxide, and irreversible oxide) were studied. Native oxide can be formed on exposing Ru in atmosphere. The reversible and irreversible oxides can be formed by applying electrochemical potential. Investigation of Cu under potential deposition on these oxides indicates the similarity between native and reversible oxides by its nature of inhibiting Cu deposition. Irreversible oxide formed on Ru surface is rather conductive and interfacial binding between Cu and Ru is greatly enhanced. After deposition, bimetallic corrosion of Cu/Ru in different polyphenols was studied. Polyphenols are widely used as antioxidants in post chemical mechanical planarization (CMP). For this purpose, different trihydroxyl substituted benzenes were used as antioxidants. Ru, with its noble nature enhances bimetallic corrosion of Cu. Gallic acid (3,4,5 - trihydroxybenzoic acid) was chosen as model compound. A mechanism has been proposed and validity of the mechanism was checked with other antioxidants. Results show that understanding the chemical structure of antioxidants is necessary during its course of reaction with Cu.

Preferential weld corrosion (PWC) remains a major operational challenge that jeopardizes the integrity of oil and gas production facilities. It is the selective dissolution of metal associated with welds, such that the weld metal (WM) and / or the adjacent heat-affected zone (HAZ) corrode rather than the parent metal (PM). Corrosion inhibition is conventionally used to mitigate this problem however several indications suggest that some corrosion inhibitors may increase PWC. Furthermore, it is not possible to detect systems that are susceptible to PWC and or to understand the apparent ineffectiveness of some corrosion inhibitors at high flow rates. Consequently, the aim of this research is to assess the suitability of submerged jet impingement method to study flow accelerated preferential weld corrosion, which is critical to safe and economic operations of offshore oil and gas facilities. In this research, a submerged jet-impingement flow loop was used to investigate corrosion control of X65 steel weldment in flowing brine, saturated with carbon dioxide at 1 bar, and containing a typical oilfield corrosion inhibitor. A novel jet-impingement target was constructed from samples of parent material, heat affected zone and weld metal, and subjected to flowing brine at velocities up to 10 ms- 1 , to give a range of hydrodynamic conditions from stagnation to high turbulence. The galvanic currents between the electrodes in each hydrodynamic zone were recorded using zero-resistance ammeters and their self-corrosion rates were measured using the linear polarisation technique. At low flow rates, the galvanic currents were small and in some cases the weld metal and heat affected zone were partially protected by the sacrificial corrosion of the parent material. However, at higher flow rates the galvanic currents increased but some current reversals were observed, leading to accelerated corrosion of the weld region. The most severe corrosion occurred when oxygen was deliberately admitted into the flow loop to simulate typical oilfield conditions. The results are explained in terms of the selective removal of the inhibitor film from different regions of the weldment at high flow rates and the corrosion mechanism in the presence of oxygen is discussed.

L’objectif de ce travail de thèse a été d’évaluer les propriétés inhibitrices de corrosion d’un traitement multifonctionnel utilisé dans l’industrie pétrolière. Dans la première partie de la thèse, l’influence des conditions hydrodynamiques, du temps d’immersion et de la température sur les processus de corrosion de l’acier API 5L-X65 en milieu CO2 en l’absence d’inhibiteur a été étudiée par des mesures électrochimiques (courbes de polarisation, courbes de Levich et spectroscopie d’impédance électrochimique) avec une électrode à disque tournant. A partir de ces essais, la vitesse de corrosion a été calculée pour les différentes conditions expérimentales. L’analyse couplée des résultats électrochimiques et des analyses de surface suggèrent la formation d’une couche de produits de corrosion, principalement de carbonate de fer qui recouvre la surface du métal et conduit à la diminution de la vitesse de corrosion quand le temps d’immersion, la vitesse de rotation et la température augmentent. La deuxième partie de la thèse a été consacrée à l’évaluation d’un traitement multifonctionnel contre la corrosion. Ce traitement est composé principalement de produits extraits de l’Aloe Vera (gel de l’Aloe Vera et « acibar »). Ces produits ont été choisis car ils empêchent la formation simultanée d’hydrates et de carbonate de calcium. Ces composés « verts », ainsi que la dodécylamine, qui est un inhibiteur de corrosion commercial, ont été testés à l’aide des mesures électrochimiques et par perte de masse afin de comparer leur efficacité et d’évaluer un possible effet de synergie lorsqu’ils sont utilisés en mélange. Les produits testés séparément ont un pouvoir protecteur comparable et il n’a pas été mis en évidence d’effet de synergie. En revanche, il a été montré que les composés sont compatibles entre eux. Ceci constitue un point très important pour l’utilisation de ces traitements qui permettent d’augmenter la fiabilité et la rentabilité pour la production du pétrole et du gaz. / The objective of this work was to evaluate the corrosion inhibitive properties of a multifunctional treatment used in the petroleum industry. In the first part of the thesis, the influence of hydrodynamic conditions, immersion time and temperature on the corrosion process of API 5L-X65 steel in CO2 medium in absence of inhibitor was studied by electrochemical measurements (polarization curves, Levich curves and electrochemical impedance spectroscopy) with a rotating disk electrode. From these tests, the corrosion rate was calculated for different experimental conditions. The analysis of the electrochemical results and surface analyses suggest the formation of a layer of corrosion products, mainly iron carbonate which covers the metal surface and leads to the decrease of the corrosion rate when the immersion time, the rotation speed and temperature increase. The second part of this work was devoted to the evaluation of a multifunctional treatment against corrosion. The treatment is mainly composed Aloe Vera extracts (Aloe Vera gel and "acibar”). These products were chosen because they prevent the simultaneous formation of hydrates and calcium carbonate. These "green" compounds and dodecylamine, which is a commercial corrosion inhibitor, were tested using electrochemical measurements and by mass loss in order to compare their efficiency and to evaluate a possible synergistic effect when they are used as a mixture. The products tested separately have a similar efficiency and did not reveal any synergistic effect. However, it was shown that the compounds are compatible. This is an important point for the use of these treatments which can increase the reliability and profitability for the production of oil and gas.