Browsing by Author "Oloruntoba, D. T."

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Comparative study of corrosion behaviour of galvanized steel and coated Al 3103 roofing sheets in carbonate and chloride environments
(2009) Oloruntoba, D. T.; Oluwole, O. O.; Oguntade, E. O.
This work studied the comparative corrosion behaviour of Al3101 and galvanized steel roofing sheets in 1M, 0.5M and 0.3M solutions of sodium carbonate and sodium chloride. Samples of the aluminium and galvanized sheets were subjected to the different environments for thirthy days. The electrode potentials, in mV(SCE), were measured everyday. Electrode potential measuremets were taken everyday for thirty consecutive days. Weight loss or gain measurements were taken every three days for the duration of the exposure period. The results showed sodium chloride environment had higher corrosive effects on the galvanized roofing sheet than sodium carbonate environment while the reverse was true for aluminium sheets. Also, galvanized steel roofing corroded more than aluminium roofing in both carbonate and chloride environments. Corrosion of galvanized steel roofing was continous throughout the exposure period in all the environment used. Galvanized steel roofing sheet is not good material for roofing in carbonated and chloride environments or in industrial environments where chloride or carbonate contamination is possible.
Effect of zinc plating of low carbon steel on corrosion resistance in cassava fluid environment
(2008-12) Oluwole, O. O.; Oloruntoba, D. T.; Awheme, O.
This research work investigated the corrosion resistance of zinc plated low carbon steel in cassava fluid (i.e. containing hydrogen cyanide). It simulated the effect of continuous use of the material in a cyanide environment where corrosion products are left in place. Low carbon steel samples were zinc electroplated at voltages between 0˙5 and 0˙9 V for 5 to 20 min. The plated samples were then subjected to a cassava fluid environment for 30 days. The electrode potentials, in mV (SCE), were measured every day. Weight loss was determined at intervals of 5 days for duration of the exposure period. The result showed corrosion attack on the zinc plated steel, the severity increasing with increasing weight of zinc coating on substrate. The result showed that thinly plated low carbon steel did not have any advantage over unplated steel and were quickly stripped of their zinc plating with resultant corrosion of the underlying steel substrate. Heavily zinc plating steel was observed to offer some protection for the steel but not for a long time. The pH of the cassava solution which initially was acidic because of the cyanide content in the cassava was observed to progress to neutrality after 5 days and then became slightly alkaline at the end of the 30 days test (because of corrosion product contamination of the cyanide), contributing to the reduced corrosion rate. Unplated steel was found to be unsuitable for the fabrication of cassava processing machinery without some form of surface treatment, but unfortunately, zinc is not suitable as a protective coating in this environment.
Effect of zinc plating of low carbon steel on corrosion resistance in cocoa fluid environment
(Elsevier, 2008) Oluwole, O. O.; Oloruntoba, D. T.; Awheme, O.
"This work investigated the corrosion resistance of zinc-plated low carbon steel in cocoa fluid. Low carbon steel samples were zinc electroplated at voltages between 0.5 V and 0.9 V for 5–20 min. The plated samples were then subjected to a cocoa fluid environment for 30 days. The electrode potentials mV (SCE) were measured every day. Weight loss was determined at intervals of 5 days for the exposure period. The result showed corrosion attack on the zinc-plated steel, the severity increasing with the increasing weight of zinc coating on substrate. The result showed that thinly plated low carbon steel generally did not have any advantage over unplated steel. Heavily zinc plated steel was observed to offer some form of protection for the plated steel as passivation was observed to occur on the nineth day of corrosion leading to almost nil corrosion rate. The pH of the cocoa solution which initially was acidic was observed to progress to neutral after 5 days, contributing to the near nil corrosion rates in the plated samples after 15 days. It was observed that electroplated steel plate at 0.8 V for 5 min and the more heavily plated steel at 0.9 V for 10 min gave the best resistance to cocoa fluid corrosion attack in the 30 days test period. Unplated steel was found to be unsuitable for the fabrication of cassava processing machinery without some form of surface treatment. "