Research Articles in Mechanical Engineering
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Item 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 AkinlabiThe 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.Item CORROSION BEHAVIOR OF Al/SiC/PKSA HYBRID COMPOSITES IN 1.0 M H2SO4 ENVIRONMENT USING POTENTIODYNAMIC POLARIZATION TECHNIQUE(SCICELL, 2022-12-13) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Emmanuel Ajisegiri; Moses FajobiThe potentiodynamic polarization of aluminium 6063 alloy reinforced with silicon carbide (SiC) and palm kernel shell ash (PKSA) particulates at various mixing ratios were investigated. Double stir casting method was adopted for the production of the hybrid reinforced composites. The existence of the reinforcements within the matrix alloy acted as active sites for corrosion initiation. Hence, pitting corrosion was observed. The range of values for Ecorr and Icorr obtained at 24 h in 1.0 M H2SO4 were between -627.74 and -644.46 mV, and between 423.81 and 860.23 µA/cm2, respectively. The Ecorr values ranged from -654 to -697.22 mV, and the Icorr ranged from 1075.65 to 3057.16 µA/cm2 at 72 h in 1.0 M H2SO4. The relative resistance to corrosion of the samples is dependent on the thin oxide film formed on the surface of the samples.Item Electrochemical investigation of the corrosion susceptibility of hybrid reinforced Al6063 with SiC and PKSA in 1.0 M sulfuric acid environment(Wiley, 2023-07-24) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Akintunde Sunday Onaolapo; Prabhu ParamasivamThe recycling of agro-waste as complementary reinforcements has received significant recognition in the development of aluminium matrix composites. Hence, this study examines the corrosion behavior of Al6063 reinforced with hybrid SiC/PKSA (palm kernel shell ash) particles. Through various ratios of SiC and PKSA particles in Al6063 alloy, composites were fabricated by double stir casting. Samples were cut and metallographically prepared for 1 M H 2 SO 4 solution corrosion experiments. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic analyses were employed. The composites corroded initially at relatively high rates, gradually declining during long immersion times in the acidic solution. The intersection of reinforcements at the general surfaces of the composites where flawed oxide skins predominate acted as active sites for corrosion initiation. From potentiodynamic polarization studies, the corrosion currents increased with time for all specimens, with A9 being 1075.65 μA/cm 2 at 72 h as against 857.99 μA/cm 2 at 24 h of measurement. The corrosion potentials for all the specimens hovered around −654.00 to −647.22 mV. Bode plots revealed similar electrochemical reactions over all the substrates’ surfaces. The relative corrosion resistance by the specimen depends on the oxide films’ nature as the cathodic interfacial reinforcements dropped off into the acidic environment.Item Application of Conversion Coatings on Aluminum Matrix Composites for Corrosion Protection(Portugaliae Electrochimica Acta, 2025-02-02) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; T. A. Orhadahwe; A. A. Samuel; J. A. Okolie; P. O. Omoniyi; T. C. JenAccelerated corrosion is closely associated with the inclusion of secondary reinforcement particulates in metal matrices, where they are usually present as cathodic sites. This hinders full utilization of composite products for engineering applications. In this study, chemical CC were used to improve MMC corrosion in atmospheric and simulated seawater environments. Comparison between CCC and PPCC performance was done to find a substitute for the former, which contains carcinogenic Cr VI ions. Japanese industrial testing method was used to determine the composite LC/CC samples adhesion characteristics, after a series of exposure regimens. CCC specimens displayed marginal corrosion resistance superiority over their PPCC counterparts. There was little to no pits on the CC substrate compared to the non-coated samples. The CC applied on the substrates prevented the coating delamination. The lacquer remained unpeeled on the substrate, during Japanese industrial testing. This indicates reduced corrosion activities on the substrates.Item 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 OmoniyiThe 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.Item Recent Development in Casting Technology: A Pragmatic Review(International Information and Engineering Technology Association, 2022-04-30) Adekunle Akanni Adeleke; Makanjuola Oki; Ikechukwu K. Anyim; Peter Pelumi Ikubanni; Adeolu A. Adediran; Ayokunle A. Balogun; Thomas A. Orhadahwe; Peter O. Omoniyi; Adebayo S. Olabisi; Esther T. AkinlabiMore reliable and durable parts with high structural integrity are required to meet the increasing advancements in science and technology. This paper reviews five (5) different casting techniques: squeeze casting, sand casting, investment casting, die casting, and continuous casting. Their respective cast products were examined, and their various mechanical properties were discussed. However, these different casting techniques involve a similar fundamental procedure: melting metal, pouring it into a mold, and allowing it to solidify. However, they vary in their physical and mechanical properties, durability, and surface finishing, making one technique more desirable than the other in their application areas. Some techniques were found to be more advantageous and effective than the other, which will aid foundrymen in making the best decision in choosing a technique, considering parameters such as environmental friendliness and cost implications. The appropriate implementation of these will help restructure and refine foundries, improve the quality of cast products, and set the casting technology world on course for the new age.Item Corrosion rates of green novel hybrid conversion coating on aluminium 6061(Elsevier, 2020-08-19) Makanjuola Oki; A.A. Adediran; Peter Pelumi Ikubanni; O.S. Adesina; Adekunle Akanni Adeleke; S.A. Akintola; F. Edoziuno; A. AleemThe 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.Item Influence of temperature on the chemical compositions and microstructural changes of ash formed from palm kernel shell(Elsevier, 2020-09-30) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Adediran, A.A; O.S. AdesinaThis study investigated the characteristics of raw palm kernel shell (raw PKS) and the influence of temperature variation on palm kernel shell ash (PKSA). The PKSA was obtained under different temperature regimes of 900, 1000, and 1100°C. The characterization of the samples was carried out using X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) with attached Energy Dispersive X-ray (EDX) facilities. The results showed that moisture and ash contents and the density of raw PKS were 6.56%, 8.86%, and 745 kg/m3, respectively. The colour of the pulverized PKS was dark brown, as observed by visual examination based on standard colour gradation. This colour transformed into various shades of brown when PKS was subjected to different temperature regimes to form PKSA. The XRF analysis showed that silica is the main constituent of the raw PKS and PKSA samples. Silica content in the PKSA increased with the rise in the heating temperature. The FTIR and EDX spectra confirmed the predominance of silicon compounds with functional groups associated with silanol and siloxane. Also, XRD analysis revealed that the silica contents in the samples are quartz, while SEM examinations indicated that temperature increases during processing influenced the microstructure through the reduction of pore concentration in the samples. The silica obtained from the PKSA would find applications in metal matrix composites as partial reinforcing materials.Item Optimization of the tribological properties of hybrid reinforced aluminium matrix composites using Taguchi and Grey’s relational analysis(Elsevier, 2021-07-05) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; O.O. AgboolaThe tribological properties of synthesized hybrid reinforced aluminium matrix composites (AMCs) have been optimized in this study using Taguchi and grey relational analysis (GRA), methods where a L16 orthogonal array was used for the experimental design. Hybrid palm kernel shell ash (0–6 wt.%) and SiC (2 wt.%) formed the reinforcements of interest, which were combined in ratios ranging between 2 and 8 wt.%. Different loads (250, 500, 750, and 10 0 0 g) and speeds (250, 500, 750, and 10 0 0 rpm) were used as control factors. The wear samples were produced using the double-stir casting method, while a Taber type abrasion machine was used for the wear experiments. The evaluated wear index and volume loss showed that the speed and load were better influential factors on the performance characteristics of the composites than wt.% of reinforcements. The Taguchi-Grey’s relational analysis gave the optimal combination of the process parameters for both the wear index and the volume loss as A3 B1 C1 (Reinforcement = 6 wt.%; Load = 250 g; Speed = 250 rpm) and A1 B1 C1 (Reinforcement = 2 wt.%; Load = 250 g; Speed = 250 rpm), respectively. The predicted and experimental values at the optimum conditions were confirmed to be within the range based on the performance of the confirmation test. The utilization of Taguchi and GRA methods have significantly confirmed that the influence of speed as a factor of performance was higher than load, which in turn was a better influencing factor than wt.% of reinforcementsItem Tribological and physical properties of hybrid reinforced aluminium matrix composites(Elsevier, 2021-04-14) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; A.A. Adediran; O.O. Agboola; O. Babayeju; N. Egbo; Ibrahim Momoh-Bello OmiogbemiAbstract This study considers the physical and tribological properties of hybrid reinforced aluminium matrix composites using Al 6063 alloy and silicon carbide (SiC) and palm kernel shell ash (PKSA) as reinforcements. The reinforcements used were 0, 2, 4, 6, 8, and 10 wt% in the matrix metal at different ratios of the SiC and PKSA using the double stir casting method. Experimental density and porosity of the samples were determined. Taber wear abrasion tester was utilized in the wear test experimentation. The results disclosed that the density of the composite reduced with PKSA increment, while other samples with SiC increment have improved density. The porosity percentage results showed that the double stir casting method used was acceptable as the values were within the permissible limit for cast MMCs. The sliding speed and applied load increment increased the mass loss and wear index for all the samples.