Z. Salleh

The Physical and Magnetic Properties of Electrodeposited Co-Fe Nanocoating with Different Deposition Times

Using the electrodeposition process, cobalt-iron (Co-Fe) nanocrystalline coatings were successfully synthesized onto stainless steel in deposition times of 30, 60, and 90 minutes. The temperature used throughout the process was 50°C in an acidic environment of pH 3. By changing the deposition time, physical properties such as phase and crystallographic structure, surface morphology, grain size, microhardness, and magnetic properties of Co-Fe coatings were examined. FESEM micrographs showed that the grain sizes of the coatings were in the range from 57.9 nm to 70.2 nm. Dendrite and irregular shapes were found in the microstructure of Co-Fe nanocoating. The Co-Fe nanocrystalline coating prepared in a deposition time of 90 minutes achieved the highest microhardness of 339 HVN. The magnetic properties associated with Co-Fe nanocoating at longer deposition times show greater coercivity, , and saturation magnetization, , values of 56.43 Oe and 70.45 eμ/g, respectively. The M-H curves for all the Co-Fe coatings exhibited soft ferromagnetic behaviour with narrow hysteresis loops. It was found that increasing the deposition time also improved the microhardness and magnetic properties of Co-Fe nanocoating, which is much needed for long-life high-coercivity magnetic strip card applications.

Comparison of electrical physical and mechanical properties of textile composites using microwave nondestructive evaluation

Composites are expensive and destructive test methods are normally applied to determine their physical and mechanical properties. For textile composites, a nondestructive test (NDT) could save time and save cost if the physical properties such as moisture content, weave architecture, void content and fiber volume fraction can be deduced from electrical properties. Also, there would be savings if mechanical properties such as tensile stress and elastic modulus could be determined by NDT methods. In this research, microwave NDT (MNDT) techniques such as measurement of complex permittivities are used for correlation with physical and mechanical properties. For textile composites made from E-glass, Kevlar and carbon fiber, we have measured reflection coefficients, transmission coefficients and dielectric properties using a free-space microwave measurement system. Epoxy has been used as a resin. Experimental results are reported for dielectric constants and loss tangents of textile composites. Also, measured physical and mechanical properties of textile composites are reported.

Effect of Low Impact Energy on Kenaf Composite and Kenaf/Fiberglass Hybrid Composite Laminates

Kenaf fibres recently have been a substitute material in many weight-critical applications such as aerospace, automotive and other industrial sectors. Their characteristics, such as low densities, specific strength and specific modulus are considered superior to those of metallic materials. The tensile and low velocity impact of kenaf composites and kenaf/fibreglass composites were investigated. The findings of such revealed that the tensile properties of the composites were seriously impaired even when low energy was used. As for hybrid composites, the tensile properties were hardly affected when tested with energy of below (6J). However, the tensile properties were reduced after the energy increased above (6J). Therefore, the impact damage of the composites can be predicted from measurements taken from the residual tensile strength of impacted specimens, and the damaged zones of the composites.

Corrosion investigation of Co–Ni–Fe-coated mild steel electrodeposited at different current densities and deposition times

Purpose The purpose of this study is to determine the effect of current density on the surface roughness and corrosion performance of electrodeposited Co–Ni–Fe-coated mild steel. Process variables are the key factor in controlling the electrodeposition process. It is important to study the processing parameter to optimize the mechanical and corrosion resistance performance of the coating substrate. Design/methodology/approach A low-cost electrodeposition method was used to the synthesize Co–Ni–Fe coating on the mild steel substrate. In the electrodeposition, electrochemistry concept was applied. The temperature of the process was controlled at 50 ± 5°C in an acidic environment. The influence of current density (11, 22 and 33 mA/cm2) and deposition time (15, 20 and 30 min) toward the surface roughness, hardness and corrosion rate was investigated. Findings The increases of time deposition and current density have improved the microhardness and corrosion resistance of Co–Ni–Fe-coated mild steel. The Co–Ni–Fe nanoparticles deposited at 30 min and current density of 33 mA/cm2 experienced the smallest surface roughness value (Ra). The same sample also obtained the highest Vickers microhardness of 122.6 HV and the lowest corrosion rate. This may be due to the homogenous and complete protection coating performed on the mild steel. Practical implications The findings from the study are important for future application of Co–Ni–Fe on the mild steel parts such as fasteners, car body panels, metal chains, wire ropes, engine parts, bicycle rims, nails and screws and various outdoor uses. The improvement of corrosion resistance using optimum electrodeposition parameters is essential for these applications to prolong the life span of the parts. Originality/value A new process which pertains to fabrication of Co–Ni–Fe as a protective coating on mild steel was proposed. The Co–Ni–Fe coating can enhance the corrosion protection and thus prolong the lifespan of the mild steel parts.

Effect of Alkaline Treatment on Tensile and Impact Strength of Kenaf/Kevlar Hybrid Composites

This study is about the hybrid composite which used the woven Kevlar, long Kenaf fibre, and unsaturated polyester as the matrix. It focused on the mechanical characterization and properties of hybrid composite. The hybrid composites were fabricated by treated and untreated kenaf fibre and Kevlar as reinforcement in unsaturated polyester matrix using hand lay-up process. Effect of 6wt% of sodium hydroxide (NaOH) on the hybrid composites were analyzed using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The tensile and impact performance of the samples were tested according to the standard ASTM D3039 and ASTM D3763, respectively. Based on scanning electron micrograph (SEM) morphological examination, it revealed that the interfacial adhesion between the fibre surface and polymer matrix were improved. The results proved that the alkaline treatment can help to improve the mechanical properties compared to the untreated kenaf fibre.

Slurry wear test of long kenaf polyester composite (LKPC) and long kenaf polyester with fiberglass composite

This paper presents an experimental study on the influence of fiberglass woven in Long Kenaf Polyester Composite (LKPC). Wear and friction characteristics were examined using sea water and sand as a slurry. Wear test were carried out using Slurry Erosion Test Rig (TR-40). These tests were performed at room temperature with speed of 200 rpm for every 2 km interval. The results from the tests show that mass loss were depends on the matrix composition of the composite. Surface Roughness, Ra, was consistently reduced after each test in all cases.

Synthesis Route towards Fine and Monodisperse Ni Nanoparticles via Hot-Injection Approach

Manipulation of adding sequences have been found to influence the reaction rate, thus made it easier to produced controllable Ni nanoparticles. Hot-injection approach shown capability to significantly reduce the production time of Ni nanoparticles compared to the conventional one-pot synthesis. With minor modification on conventional polyol method, narrow, monodispersed and highly yield spherical nickel (Ni) nanoparticles were successfully produced at synthesis temperature of 60°C. Three mixing methods were investigated to study its efficiency towards producing rapid and narrower size distribution of Ni nanoparticles. Reduction processes were proposed each of the method. As-synthesized Ni nanoparticles were characterized with Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM) and Fourier transform infrared spectroscopy (FTIR) to analyze the size, morphology and interaction of reactants. Fine particles size distribution revealed that when hydrazine was first heated, reaction rate improved tremendously.

Three Response Optimization of Spot-Welded Joint Using Taguchi Design and Response Surface Methodology Techniques

One of the main challenges in correlating welding parameters and weld quality is its complexity to include as many as possible factors. In this research, the effects of spot welding parameters on weld quality were investigated. The effects of weld time, weld current, and electrode force on the sizes of fusion zone and heat affected zone, and tensile-shear load were studied. These welding parameters and weld quality were analysed using the three response Taguchi L9 orthogonal array method in Minitab 17. Second-order regression models of fusion zone size, heat affected zone size and tensile-shear load were constructed by adapting Response Surface Method. The optimum weld time was 0.2 s, weld current of 10 kA and the required electrode force was 2.3 kN. These parameters were within 5% discrepancies with the experiment results. Weld current was the most important welding parameter that determines the weld quality, with the contribution of 69%. From our observation, the failure mode was the pullout type, a generally accepted failure for welded joint. The outcomes of this research contributed to the advancement in optimization technique for RSW joint, by increased the number of weld quality from two to three response.

Effect of sintering temperature on zinc substituted calcium phosphate ceramics

Calcium phosphate ceramics were substituted with several concentrations of zinc ions (0, 5, 10 and 15 mol%) using precipitation method. The effect of sintering temperature at 900 and 1000°C on zinc substituted calcium phosphate ceramics were observed. By increasing the sintering temperature, XRD peaks for zinc substituted calcium phosphate ceramics changed significantly. At sintering temperature of 900°C, hydroxyapatite phase was the major phase in the calcium phosphates containing 0 and 5 mol% zinc. However, at the sintering temperature of 1000°C, hydroxyapatite phase was partly transformed to another phase which was tricalcium phosphate. FESEM observations at sintering temperature of 1000°C exhibit that the particle size of the samples increased with addition of more zinc ions.

Effect of post weld impact treatment (PWIT) on mechanical properties of spot-welded joint

This paper focuses on the study of improvement for spot welding on the tensile shear and hardness by applying post weld impact treatment (PWIT) on the welded joint. The main objective of the research is to characterize and improve the mechanical properties of the joint. The method of PWIT used on the welded joint was Pneumatic Impact Treatment (PIT). The concept of PIT on spot welding is that it improves the mechanical properties of the welded zone. The working sample was undergoing a resistance spot welding of joining two similar in dimension and material of a steel plate before treated. The dimension of both plate are 110 mm × 45 mm × 1.2 mm and the material used were low carbon steel (LCS). All the welded samples were tested for its mechanical properties by performing the tensile-shear and hardness test. Tensile-shear test was conducted on the spot welded, both treated and as-welded samples using crosshead speed of 2 mm/min, while hardness test was performed using 1kgf load via Vickers hardness indente...