Research Articles in Mechanical Engineering
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Item Inhibition potential of silver-gold nanoparticles on mild steel in 3.5% NaCl solution(Engineering and Applied Science Research, 2023-01-01) Peter Pelumi Ikubanni; Adekunle Akanni Adeleke; Jamiu Kolawole Odusote; Tesleem B. Asafa; Sharafadeen K. Kolawole; Victor O. Ogbesanya; Jude A. OkolieThis study investigates the corrosion behaviour of silver-gold nanoparticles as an inhibitor on the degradation of mild steel in 3.5% NaCl (saline environment) using gravimetric analysis and potentiodynamic measurement. The inhibitor Ag-AuNPs was synthesized from Kola nut pod. Five different concentrations of the Ag-AuNPs solution (0, 5, 10, and 20 μg/ml) were added to the saline environment. The gravimetric result showed that inhibition efficiency of 83.33% was the highest at 20 μg/ml of Ag-AuNPs inhibitor concentration. The Tafel polarization result showed that the solution with 20 μg/ml of Ag-AuNPs had the highest inhibition efficiency of 99.465%. At 0 μg/ml of Ag-AuNps, the surface morphologies of the mild steel sample did not show the existence of Ag-AuNps constituent in the saline environment containing the nanoparticles. The outcome showed that the saline environment with 15 and 20 μg/ml of Ag-AuNPs could successfully limit the corrosion of the mild steel.Item Effect of copper addition and solution heat treatment on the mechanical properties of aluminum alloy using formulated bio-quenchant oils(Engineering and Applied Science Research, 2020-01-01) Adekunle A.S.; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Omoniyi P. O.; Gbadamosi T. A.; Jamiu Kolawole OdusoteAddition of copper and use of solution heat treatment solution with bio degradable vegetable oils as quenchants has great potential to improve the mechanical properties of aluminum and its alloys. In this study, copper was added to as-received Al- Si-Mg alloy to produce Al-Si-Cu-Mg alloy. The specimens were quenched with blended bleached bio-quenchant oils and a petroleum-based oil after solution heat treatment. The alloy was heat treated at 500℃, soaked for 20 minutes in a muffle furnace before quenching in the formulated bio-quenchant oils. The cooling properties, mechanical properties and microstructure of the solution treated specimens were determined. Blended bleached melon (BBM) oil was observed to have offered a higher cooling rate of 49.3 ℃ s-1 compared to the petroleum-based (PB) oil with a cooling rate of 25.8 ℃ s-1. Blended bleached melon oil exhibited the highest quench severity value of 1.0074 m-1, while petroleum-based oil was 0.6133 m-1. The as-received alloy and as-cast alloy specimens exhibited tensile strength values of 125.33 and 131.37 N mm-2, respectively, while a higher tensile strength value of 139.30 Nmm-2 was obtained using the blended bleached melon oil. The highest Rockwell hardness number, 61.00 HRB, was obtained using blended bleached melon oil. The overall mechanical properties of specimens improved after the addition of copper and heat treatment in various bio-quenchant oilsItem 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 Production of bioplastic films from wild cocoyam (Caladium bicolor) starch(Elsevier, 2024-10-15) Chinaza Enwere; Ikechukwu Okafor; Adekunle Akanni Adeleke; Petrus Nzerem; Khaleel Jakada; Adebayo Isaac Olosho; Peter Pelumi Ikubanni; Prabhu Paramasivam; Ayuba SalihuThis study tackles the pressing environmental challenges resulting from the rapid and ongoing use of conventional plastics by investigating biodegradable alternatives derived from wild cocoyam starch. The bioplastics developed from various formulations, incorporating gelatin, glycerine, vegetable oil, and vinegar, were systematically evaluated for their mechanical, chemical, microstructural and biodegradability properties. The addition of glycerine and gelatin enhanced the moisture content and flexibility of the films while vegetable oil improved water resistance, reducing water absorption. Th sample that contains 3 g of gelatin and 3 ml of glycerine exhibited the best overall performance with a tensile strength of 6.5 MPa and an elongation at break of 77 %. This sample also achieved an impressive biodegradation rate of 70 % within 7 days. Scanning Electron Microscopy revealed a uniform and smooth morphology, while Fourier Transform Infrared Spectroscopy confirmed the presence of key functional groups responsible for the material's performance. These results establish wild cocoyam starch as a promising resource for producing biodegradable bioplastics with considerable potential in various industries, particularly in packaging and agricultural applications. The excellent mechanical properties and biodegradability of the materials along with its natural abundance, offer an eco-friendly solution to the plastic waste problem. The study also opens new avenues for optimizing bioplastic formulations to enhance specific properties like thermal stability and moisture resistance, further broadening their practical applications. This research contributes to the sustainable materials landscape and represents a step toward reducing reliance on fossil-based plastics, advancing the global effort to mitigate environmental pollution.Item Scanning and transmission electron microscopy examinations of composite hybrid chromate and chromate phosphate conversion coatings exposed in hot 100% relative humidity environments(Elsevier, 2023-07-20) Peter Pelumi Ikubanni; Makanjuola Oki; Adesoji A. Adediran; Sarah A. Akintola; Adekunle Akanni AdelekeConversion coatings are sine qua non in the finishing of aluminium alloys. They may be put into service without coating of paints. However, for aesthetics in architectural applications, paint overcoat is common. Chromate phosphate coatings are relatively less toxic than chromate which gained the pride of place until recently. Thus, aluminium specimens coated with hybrid chromate/phosphate conversion coatings have been subjected to 100% relative humidity for 480 h at 313K in comparison to chromate coatings and bare aluminium. Scanning electron microscopy examination revealed that initial dried river bed morphologies on coated specimens were obliterated. The friable outer coatings collapsed into the cracks/environment leaving a relatively smooth surface after exposure. Additionally, transmission electron microscopy of sections before and after exposure revealed similar texture and morphological striations nearly parallel to each other throughout the length of the coatings to the metal/coating interface. These were not disrupted as well as the metal/coating interface which remained relatively smooth with no visible corrosion products after exposure. Thus, the coatings formed effective barrier between the substrate and the relatively harsh environment. From EDS, elemental compositions were the same albeit, spectral intensities remained relatively constant after humidity exposure regimes. The coatings are made up of either Cr, O and Al for chromate and Cr, P, O and Al for chromate/phosphate. At deliberately breached regions, the coatings prevented spread of corrosion and paint delamination over the substrates. On the other hand, bare aluminium was decorated with mounds of hydrated aluminium oxide/hydroxide after exposure as revealed in the SEM/TEM.