Faculty of Engineering

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Comparative Analyses of the Inhibitive Influence of Cascabela thevetia and Jatropha curcas Leaves Extracts on Mild Steel
(Nature Environment and P ollution Technology, 2020-09-04) A. S. Adekunle; Adekunle Akanni Adeleke ; Peter Pelumi Ikubanni; O. A. Adewuyi
The inhibitive properties of the extracts of Cascabela thevetia and Jatropha curcas were comparatively studied on corrosion of mild steel in H2SO4 acid. The extracts of both plants contained active phytochemical constituents such as tannins, saponins, alkaloids, flavonoids, terpenes and phenols which made them useful as good corrosion inhibitors. The extract concentrations were varied from 0.3 to 1.5 g/L during both the gravimetric and gasometric analyses for an exposure time of 7-28 days. The weight loss of the coupon, corrosion rate, surface coverage and inhibitive efficiency was evaluated for both the extracts. The results of the gravimetric and gasometric analyses indicated that inhibitive efficiency increased with an increase in the concentration of inhibitors and the highest was 55.77% for Jatrophas curcas at the concentration of 1.5 g/L. The weight loss was a little lower for Cascabela thevetia (4.36 g) compared to Jatrophas curcas (4.66 g) at the highest exposure time used (28 days). Cascabela thevetia has a better surface coverage (0.68) than Jatropha curcas (0.61), hence, Cascabela thevetia inhibits better for a 7-day exposure time. However, when the mild steel was further exposed for more than 7 days, Jatropha curcas exhibited a better inhibitive property. The highest and least hydrogen gas evolution was obtained at 0.3 g/L concentration (7 minutes) and 1.5 g/L concentration (1 minute) for both Cascabela thevetia and Jatropha curcas leaves extracts, respectively. Based on the results, the utilization of extracts of Cascabela thevetia and Jatropha curcas leaves as replacements for toxic organic inhibitors in industries are recommended.
Development of Methodology for Characterization of Surface Roughness of Solid Metallic Surfaces Using Oil Slippage Method
(Sciendo, 2021-08-12) I. O. Ohijeagbon; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; T. A. Orhadahwe; G. E. Adebayo; A. S. Adekunle; A. O. Omotosho
The study employed the phenomenon of friction between liquid droplets and solid metallic surfaces in surface roughness analysis of engineering materials. Five samples of mild steel plate were prepared to different degrees of surface roughness by facing operation. The sample surfaces were analysed to determine the roughness parameters (mean roughness, root mean square roughness, roughness skewness, and roughness kurtosis) and friction coefficient of the surfaces. Oil droplet sliding velocity was determined using the oil slippage test. The friction coefficient of the surfaces increased with increasing roughness parameter which varied from 26.334 µm at friction coefficient = 0.63 to 13.153 µm at friction coefficient = 0.46. The results from oil slippage test showed that the sliding velocity of the oil drop decreased as the friction coefficient of samples increased. At an inclination angle of 30°, sliding velocity varied from 0.51 cm/s at friction coefficient = 0.63 to 0.92 cm/s at friction coefficient = 0.46. Some of the samples exhibited a deviation in the trend of relationship between friction coefficient and sliding velocity which resulted from the variation in peak height of roughness between the sample surfaces. Oil slippage method predicts the surface behaviours of materials based on their surface parameters.
Mechanical properties and microstructural evaluation of heat-treated aluminum alloy using formulated bio-quenchants
(Akademiai Kiado, 2020-10-03) A. S. Adekunle; Tajudeen Adelani Gbadamosi; P.O. Omoniyi; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Jamiu Kolawole Odusote
Heat treatment industries require various quenching media to improve the properties of the materials to be quenched. Petroleum based mineral (PBM) oil, a non-biodegradable oil, is popular amongst others quenchants in heat treatment processes. Recently, biodegradable oils mostly in their raw, unblended and unbleached forms have been employed for quenching of various engineering materials. Therefore, the present study examined the effects of some selected bio-quenchants in blended raw (BR) and blended bleached (BB) forms on the mechanical properties and microstructure of solution heat treated aluminum (Al)-alloy. Edible vegetable oil (70% by volume) was blended with 30% by volume of jatropha oil to form the bio-quenchant oils. Another set of bio-quenchants were formed by bleaching the raw oils before mixing so as to reduce the oxidation level and contaminations in the oil. The Al-alloy is solution heat treated at 500 °C and soaked for 15 min in an electric muffle furnace before quenching in the various established bio-quenchants. Results showed that samples treated in blended raw melon (BRM) oil have higher tensile strength of 151.76 N/mm while samples quenched in blended bleached melon (BBM) oil have higher hardness value of 61.00 HRC. In accordance to the results obtained the bio-quenchants were found to be effective replacement to the PBM oil.