Petroleum Engineering

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    Conversion coating pretreatment enhances pipeline integrity
    (2018) Oki, M.; Adediran, A. A.; Ogunsemi, B.; Akintola, S. A.; Charles, E.
    It is necessary to coat both the internal and external surfaces of pipelines which transport different types of fluids that are usually contaminated with various percentages of aggressive corrosives. Pipelines pass through various terrains and highly challenging environments hence the need for both internal and external coatings to prevent corrosion and its adverse effects. In order to improve on the longevity of pipelines and the adhesion of the coating system, it is preferable to conversion coat blasted surfaces prior to application of any coating system. Improvements in pipeline coatings applications and the often neglected chromating procedure prior to coating application have been highlighted. This will prolong the lifespan of pipeline networks and secure these strategic assets from being a source of both materials and human resources drain pipes. However, the use of corrosion resistant alloys as internal lining for carbon steel pipes in the petroleum/gas industry is fast gaining recognition.
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    Corrosion protection by novel conversion coatings on structural AI 6061
    (2022) Oki, M.; Adediran, A. A.; Ikechukwu, A.; Onokohwomo, C. O.; Bosa, C.; Akintola, S. A.; Adesina, O. S.
    Chromate conversion coatings have witnessed limited acceptability in recent times. The coatings contain Cr (VI) species that have been classified as environmental hazards and injurious to human. Thus, the use of environment-friendly and non-carcinigenic novel inorganic- inorganic hybrid conversion coatings are being explored. Vanadate (VCC), hybrid Vanadate/Molydate (HCC) conversion coatings on A16061 have been classified in terms of corrosion and adhesion performance with reference to the untreated alloy. Natural exposure tests in the atmosphere and stanant near-neutral 3.5% sodium chloride solution, as well as patentio-dynamic polarization measurements showed that the corrosion rate for HCC is lower for Vanadate, which in turn outclassed the ‘bare’ alloy. However, clusters of passive incipient pits were revealed on the former after 120 h of exposure in stagnant chloride solution. Both conversion coatings outperformed the untreated aluminiun alloy after atmospheric corrosion and adhesion tests.
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    Corrosion rates of green novel hybrid conversion coating on aluminium 6061
    (Elsevier, 2020) Oki, M.; Adediran, A. A.; Ikubanni, P. P.; Adesina, O. S.; Adeleke, A. A.; Akintola, S. A.; Edoziuno, F.; Aleem, A.
    The use of chromate conversion coatings have been limited by several protocols as a result of their carcinogenicity and toxicity towards humans and the environment. Searches are ongoing for chromate replacement in coating baths and processes. This paper describes the comparison among the corrosion rates of a novel hybrid conversion coating derived from water extracts of hibiscus sabdariffa calyx in conjunction with ammonium molybdate, a molybdate conversion coating and the so-called chromate conversion coating. Potentiodynamic polarization measurement in 3.5 wt% sodium chloride solution was employed in ranking the coatings as sabdariffa molybdate being more corrosion resistant than chromate, which in turn out performed molybdate.
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    Reinforcement bar corrosion - causes and management
    (IOP Publishing Ltd, 2019) Oki, M.; Akintola, S. A.; Adediran, A. A.; Peter, P.; Ikubanni, P. P.; Ogunsemi, B. T.
    Concretes are composite materials which decay as a result of steel corrosion in concrete structures is mostly accelerated in environments laden with chlorides and industrial effluent gases as well as harsh chemicals employed in and those generated from wastes in agricultural industries. This review summarises the effects of various environmental pollutants which promote deterioration of concretes with resultant corrosion of reinforcing bar (rebar). An overview of traditional and current methods for significant reduction of this mode of material deterioration is described. Discussions on management tools for rebar corrosion in agricultural and marine environments have been highlighted. Repair methods include the traditional application of patch repair mortar which has been modified with polymeric materials to improve adhesion and reduce porosity. The use of cathodic protection system to reduce rebar corrosion to its barest minimum has gained currency. Attention should be directed at corrosion reduction practices at the design and planning stages as well as modification concrete mixes with modified agricultural wastes/products and polymers.
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    Valorized chicken feather as corrosion inhibitor for mild steel in drilling mud
    (2019) Akintola, S. A.; Oki, M.; Aleem, A. A.; Adediran, A. A.; Akpor, O. B.; Oluba, O. M.; Ogunsemi, B. T.; Ikubanni, P. P.
    Modified chicken feather reduced the corrosion rate of mild steel in drilling mud as deduced from electrochemical potentiodynamic polarization technique, albeit, with observed infestation of the test environment by microbes over protracted exposure period of 92 days. The corrosion rates with and without the addition of 0.3g of hydrolyzed feather per 100 ml of drilling mud were 1.70 and 1.95 mm/yr, respectively; which corresponded to inhibition efficiency of 13% over the immersion period. The corresponding charge transfer resistances, a measure of corrosion rates were 1480.4 and 1780.0 Ω, respectively; in the uninhibited and hydrolyzed-feather inhibited environments. The voltage over the double layer capacitor as obtained from the polarization studies numerical increased from -0.907 to -0.948 V which indicated adsorption of moieties in the inhibitor and probably some corrosion products on the surface of the mild steel specimen.