Department of Mechanical Engineering
Permanent URI for this collection
Browse
Recent Submissions
- ItemValorized rice husk as green corrosion inhibitor for Al 6061 in 1M HCl(Research on engineering structures & materials, 2024-01-07) Adesina, OlanrewajuThis study investigated the inhibition characteristics of rice husk (RH) on corrosion of Aluminum 6061 in 1M hydrochloric acid. Gravimetric analysis and Scanning Electron Microscopy (SEM)/ Energy Dispersive X-ray analysis (EDX) as well as electrochemical studies revealed the potency of RH as a good inhibitor of the corrosion of Al 6061 in 1M HCl. Fourier Transform Infrared Spectroscopy (FTIR) indicated that –OH, C=C, and C=O with signals at (3317.19, 2932.9, 2848.2), (1631.8) and (1105.73, 1030.2, 447.15), respectively in RH were the viable active functional groups which adsorbed on the metal surface to effect reduction of corrosion rates. However, literature suggested the presence of amorphous silica in RH which served as a complimentary corrosion inhibitor. The corrosion current density of Al 6061 was reduced to 3.46 × 10−7 A/cm2 at 24 h as against 9.27 × 10−7 A/cm2 at the commencement of the potentiodynamic polarization measurements in inhibited 1M HCl. The control specimens exhibited an average corrosion rate of 3.86 × 10−6 A/cm2 in HCl solution at the start of this investigation as compared to the corrosion rate of 3.46 × 10−7 A/cm2 at 24 h of exposure in 5 mg RH- inhibited HCl. The obtained results gave a corrosion inhibition efficiency of about 90 to 92%.
- ItemModeling and optimization of green-Al 6061 prepared from environmentally source materials(Heliyon, 2023-07-19) Adesina, OlanrewajuRecent studies are evaluating the use of particulates fabricated from agro-based residues as reinforcement for enhancing the properties of aluminium alloys. This report focuses on the optimization approach and modeling of responses for future prediction, which are absent from the majority of studies involving particle reinforcement of an aluminum matrix. Herein, palm kernel shell ash (PKA) and rice husk ash (RHA) were incorporated with 4 wt% of WSD and used as f illers in the Aluminium-6061 matrix at variable proportions. The response surface approach was utilized in the experiment design, modeling, and outcome optimization. The independent vari ables are the proportions of PKA and RHA and stir casting temperature. Yield, ultimate tensile, impact strength, elastic modulus, and fracture toughness are examined as response parameters. The results demonstrated that the microstructural property played a significant role in the re sponses. Incorporating PKA and RHA into the Al-6061 matrix improved the response parameters. Temperatures in the range of 700 and 800 ◦ temperatures within 800 and 900 ◦ C enhanced the property parameters, even though C caused a decline in response. The dependence of the re sponses on the pattern between property variables was revealed by surface and contour plots. The development of models for predicting responses. Optimal conditions were reached at 4.03% PKA, 5.12% RHA, and 787 ◦ validating the model. C, with an error <5% when compared to the forecast responses, thus
- ItemEffect of SiC addition on Laser‑based CoNi Binary Alloy Coatings on Ti‑6Al‑4V alloy(Springer, 2024-04-25) Adesina, OlanrewajuThis research explores the impact of variations in laser scanning speed and the incorporation levels of SiC-Ni-Co powders on Ti-6Al-4V alloy using laser surface cladding technique. Key parameters, including a consistent laser power of 700 W, a 4 mm beam spot size, a powder feed rate of 1.0 g/min, and a gas fow rate of 3 L/min, along with fxed powder composi tions, were maintained. The laser scanning speeds were adjusted to 0.4 m/min, 0.8 m/min, and 1.2 m/min. Microstructural analyses were carried out using scanning electron microscopy (SEM) while Vickers microhardness was employed to assess coating hardness, and corrosion properties were evaluated using a linear potentiodynamic polarization technique. Follow ing the corrosion attack, the protective oxides formed were identifed through SEM and X-ray difractometer (XRD). The results revealed a strong metallurgical relationship between the clad layer and the substrate, demonstrating the efectiveness of the laser-clad technique. Particularly, the highest laser scan speed exhibited the most signifcant improvements in hardness and corrosion resistance. The coatings displayed an average hardness value of 1269.20 HV0.1, a notable fourfold increase compared to the substrate's value of 334 HV0.1. Concerning corrosion, a clear correlation emerged between scan speed and polarization resistance, confrming that higher scan speeds could lead to enhanced polarization resistance
- ItemOptimization and Inhibitive effects of Sweet Potato Leaf Extract (SPLE) on mild steel(Elsevier, 2023-02-02) Adesina, OlanrewajuWeight loss and electrochemical techniques were used to evaluate the inhibition efficiency of sweet potato leaf extracts (SPLE) as inhibitor on mild steel in phosphoric acid. Box Behnken design was used to examine the interactions of these variables: acid concentration (0.5–1.5 M); time (5–10 days); inhibitor concentrations (0.3–0.9 g/L) and temperature (30–60 ◦ C) respectively. Polarization and Electrochemical impedance and were used to measure the inhibition efficiency. The surface morphology of coupons was analysed using Scanning Electron Microscope (SEM). The experimental data was statistically analysed and regression equation was generated for inhibition efficiency. The weight loss measurement revealed that extract acts as an inhibitor for mild steel in phosphoric acid and decreases rate of corrosion. The results of inhibition effi ciency derived from polarization studies and impedance analyses agree. The validated experi ment’s coupon created a better protected inhibitive layer than coupon of the best process level as observed from experimental design, according to SEM analysis. It can be concluded that the extract operated as an inhibitor by producing outer film on the surface of mild steel.
- ItemDevelopment of Sacrificial Anode from Al, Mg, and Ti from Iron Ore Tailings(Taylor & Francis Group, 2024-03-07) Adesina, OlanrewajuThis investigation used aluminium, magnesium, iron ore tailings, and low-carbon steel. Iron ore tailings (5–30 wt% Mg and 50 μm in size) in an aluminium matrix formed the anode. In 0.5 M NaCl solution, the weight loss, corrosion rate, and electrochemical properties were measured. Samples A to E have corrosion rates of 0.43, 0.28, 0.36, 0.08, and 0.11 mm/yr, respectively. SEM/ EDS examination revealed the presence of elemental Al, Mg, O, and Si in the anode. The XRD patterns indicate intermetallic compounds such as iron nitride (Fe3N), aluminium silver (Ag-Al), and manganese zirconium (Mn2Zr). In samples A, B, and C, Al and Mg formed a protective coating on the anode, while C and Si reduced passivation and released electrons to protect the steel. IOTs and Mg in the aluminium matrix improve the anodic corrosion resistance. The observed improvements in corrosion resistance highlight the potential of these sacrificial anodes for practical applications in corrosion protection systems