Faculty of Engineering

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Electrochemical Studies of the Corrosion Behavior of Al/SiC/PKSA Hybrid Composites in 3.5% NaCl Solution
(MDPI, 2022-09-30) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Olanrewaju Adesina; Peter Omoniyi; Esther Akinlabi
The corrosion behavior of metal matrix composites (MMCs) is accelerated by the inclusion of reinforcements. Hence, this study investigates the corrosion behavior of MMCs produced from Al 6063 matrix alloy with reinforcement particulates of silicon carbide (SiC) and palm kernel shell ash (PKSA) inclusion at different mix ratios. The MMCs were synthesized using the double stir casting technique. The corrosion behaviors of the composites in NaCl solutions were studied via gravimetric analysis and electrochemical measurements. The gravimetric analysis showed fluctuating dissolution rate of the samples in NaCl solution to indicate flawed film as well as corrosion product formation over the surface of the specimens. The observed corrosion mechanism of the samples was general and pitting corrosion. The presence of reinforcements within the Al6063 matrix acted as active sites for corrosion initiation. The range of values for Ecorr and Icorr obtained in 3.5% NaCl at 24 h was between −220.62 and −899.46 mV and between 5.45 and 40.87 µA/cm2, respectively, while at 72 h, the Ecorr values ranged from 255.88 to −887.28 mV, and the Icorr ranged from 7.19 to 16.85 µA/cm2. The Nyquist and Bode plots revealed the electrochemical corrosion behavior of the samples under investigation, with predominant reactions on the surface of the samples linked to charge transfer processes. The relative resistance to corrosion of the samples depends on the thin oxide film formed on the surface of the samples.
PHYSICO-TRIBOLOGICAL CHARACTERISTICS AND WEAR MECHANISM OF HYBRID REINFORCED Al6063 MATRIX COMPOSITES
(SciCell, 2021-02-02) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Olanrewaju Adesina; Peter Omoniyi
The development of engineering materials is continuously attracting attention from scientists and engineers for numerous engineering applications. The physical properties and wear mechanism of aluminium (Al 6063) matrix reinforced with silicon carbide (SiC) and palm kernel shell ash (PKSA) particulates at different weight ratios ranging from 0 to 10 wt. % with 2 wt.% intervals were investigated. The liquid route of double stir casting was employed in synthesizing the composites. The wear experiment was conducted using the Taber-type wear abrasion machine. The worn surfaces were examined using scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDS), while the intermetallic phases were examined using the x-ray diffractometer (XRD). From the result, the increase in PKSA and SiC lowered and improved the density of the composites, respectively. The percentage porosity values (2 - 2.4%) obtained in this study were found to be within the acceptable limit of less than 4% for metal matrix composites castings. The mass loss and wear index increased owing to the rotating speed and applied load increase due to the occurrence of mechanical mixing between the contacting surface of the sample disk and the machined disc. Adhesive and abrasive wear mechanisms were the major mechanisms observed in this study. The produced sample showed low wear resistance and will be found useful in areas with low frictional interactions.
Evaluation of Non-Isothermal Kinetic Parameters for Pyrolysis of Teak Wood using Model-Fitting Techniques
(TRENDS IN SCIENCES, 2021-12-21) Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Jamiu Kolawole Odusote; Thomas Orhadahwe; Olumuyiwa A. Lasode; Samuel Adegoke; Olanrewaju Adesina
Teak wood is one of the prominently used raw material in the construction industry, thus contributing extremely to the biomass waste available in Nigeria. These wastes are usually used for energy generation that requires upgrade into better fuel before application. Hence, the present study evaluates the non-isothermal kinetic parameters for pyrolysis of teak wood using model-fitting techniques. Teak wood dust was subjected to proximate, ultimate and calorific value analyses based on different ASTM standards. The thermal degradation and decomposition behaviour of the teak wood dust was examined using a thermogravimetric analyzer. Pulverized teak (6.5 mg) was heated from 30 to 800 ºC at varying heating rates (5, 10 and 15 ºC) in an environment where 100 mL/min of nitrogen gas was charged in continuously to maintain an inert condition. Avrami-Erofeev, Ginstling-Broushtein (GB) and Mampel models were used to evaluate the kinetic parameters of the pyrolysis of teak wood dust. The teak wood dust contained 7.25 % moisture, 79.26 % volatile matter (VM), 1.74 % ash and 11.75 % fixed carbon. The calorific value of the wood dust was 18.72 MJ/kg. The results of the thermogravimetric analyses depicted that heating rate has no effect on weight loss during the reactive drying zone. However, as the thermal treatment progressed into the active pyrolysis and passive pyrolysis zones, the weight loss decreased with increase in heating rate. The devolatilization parameters also increased with heating rates except for the maximum conversion. The results of the kinetic parameters evaluation revealed that the GB model was best fit to evaluate the kinetic parameters of teak in the active pyrolysis zone while GB and Mampel models were considered most appropriate for the evaluation of the kinetic parameters in the passive pyrolysis zone. Model-fitting method has the capacity to capture a wide range of fractional conversion at a glance

Faculty of Engineering

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