Now showing 1 - 10 of 26
  • Publication
    Suppression of (Cu,Ni)6Sn5 Intermetallic Compound in Sn-0.7Cu-0.05Ni+1wt.TiO2 Solder Paste Composite Subjected to Isothermal Aging
    ( 2020-03-18)
    Mohd Said R.
    ;
    ;
    Salleh M.M.
    ;
    This paper investigated the intermetallic compound (IMC) layer that formed in Sn-0.7Cu-0.05Ni+1wt.% TiO2 (SCNT) composite solder paste added with reinforcement (TiO2) particles. Besides, the growth of the IMC layer during subsequent aging at temperature of 75 °C, 125 °C and 150 °C also being studied. Scanning electron microscopy was used to observe the IMC growth and to measure the thickness of IMC layer. The interfacial IMC layer has been suppressed whereas the activation energy value of the composite solder paste was high (37.35 kJ/mol) which in turn improved the thermal stability of the IMC layer. Results also show the IMC formed at bulk solder microstructure of SCNT solder paste composite was refined. The presence of TiO2 particles has become the obstacle for the Cu atom diffusion from the substrate to the solder and Sn atom from the solder, thus, successful for the suppression of the IMC layer.
  • Publication
    Characterization of Al–Mg Alloy by Powder Metallurgy Technique
    ( 2023-01-01) ;
    Mohd Asri N.M.
    ;
    The powder metallurgy Al has been widely used in the heavy industry, especially in precision technology. Unfortunately, these new materials are problematic in powder metallurgy production and corrosion problems. This research paper aims to study the influence of Mg contents (10, 25, 50, 75, and 90) wt% on microstructure and corrosion behavior on Al–Mg alloy by using powder metallurgy techniques. Al–Mg powder was mixed using a rotation mill with a rotation speed of 120 rpm for 30 min. Then, the mixed powders were compacted at a pressure of 150 MPa. Sintering was done in an argon-controlled atmosphere at a temperature of 500 Â°C. An optical microscope was used to observe the microstructure of sintered sample; meanwhile, X-ray diffraction (XRD) was used to analyze phase identification. A potentiostat was used to study the corrosion behavior of sintered Al–Mg alloy. The results revealed that Al–90 wt% Mg gives a high corrosion rate.
  • Publication
    Corrosion Resistance of Micro-Textured Surface Modified Alumina-Titania Coating
    ( 2020-03-18)
    Wahab J.A.
    ;
    Ghazali M.J.
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    Effect of micro-texture on the corrosion resistance of alumina-titania coated mild steel was investigated. The micro-texture was fabricated on the coating surface via laser surface texturing technique. Tafel extrapolation and immersion test was conducted to measure the corrosion resistance and corrosion mechanism of the coating in 3.5% NaCl solution. The results indicated that the micro-texture contributes to a significant improvement of corrosion resistance due to the formation small volume of air trapped in the micro-grooves, which resist the penetration of corrosive ions and reduce the area of solid-liquid interface. The WCA indicated that the textured surface had low wettability. The SEM analysis showed the occurrence of uniform corrosion. The analysis of EDS revealed that there was formation of corrosion product at the coating-substrate interface. In short, the resistance towards corrosion was increased up to 73% indicating that the resistivity of the coating against corrosion was improved by engraving the micro-texture on its surface.
  • Publication
    Study on the effects of anodizing voltage to the AAO thin film dimensional properties synthesized by single step anodization method
    Anodic aluminium oxide (AAO) thin film electrodes were synthesized by using a single step anodizing method in 15 °C of 0.3 M oxalic acid at five different anodizing voltage ranging from 20 V to 60 V, respectively. The effect of anodizing voltage to the AAO dimensional properties were about to be investigated. Morphological observations were all done by FESEM where the measurements and calculation were made by using ImageJ and formulas. To ensure that the pore sizes were totally depended on the anodizing voltage, etching process were done at constant duration for all samples. The correlation between all AAO dimensional properties like pores size, interpore distance, wall thickness, pore density, percentage of porosity and nanoporous oxide thickness were presented in a linear graph.
  • Publication
    Oxide Film Formation on Stainless Steel 304L by Anodizing Method with Different Power Sources
    In order to generate a nanoporous oxide film, stainless steel 304L is anodized using an alternating current (AC) and direct current (DC) source in an ethylene glycol solution containing ammonium fluoride, NH4F, and water, H2O. This study focuses on the differences between AC and DC anodizing in terms of current density versus time response, thickness, and depth of the oxide film formed on the anodized specimens, surface roughness, and element composition of the specimens because there is limited study on AC anodizing of stainless steel. In 0.5% of 0.3M NH4F and 3% H2O in ethylene glycol solution, the AC and DC anodizing are conducted for 30 minutes at voltages ranging from 30V to 50V and 21.2 V to 35.4 V, respectively. The current density versus time response revealed that AC anodizing produced more current density than DC anodizing. As for the thickness and depth of the generated oxide films, only the specimens that have been anodized in AC indicated an increase in these films, whereas specimens that have been anodized in DC showed the metal dissolving as the specimens degraded. The surface roughness of AC anodized specimens reduced with increasing anodizing voltage, whereas DC anodized specimens increased with increasing anodizing voltage. The element composition of the anodized specimens revealed that the mass percentage of oxygen, O element is higher for AC anodized specimens compared to DC specimens. This suggests that AC anodizing on stainless steel might offer important advantages and should be further researched.
  • Publication
    Impact of AC Anodizing on SS304L Oxide Film and Its Effect on Hydrogen Evolution Reaction (HER) Properties
    The effect of AC anodizing on the formation of oxide film on stainless steel 304L (SS304L) surfaces and its influence on the hydrogen evolution reaction (HER) were studied in this study. The SS304L specimens were prepared before being anodized for 30 minutes at various voltages (range from 10 V to 50 V) using an AC power supply at room temperature. The surface morphology is studied using scanning electron microscope (SEM) and 3D profilometer. A potentiostat is used to run linear sweep voltammetry (LSV) and Tafel analysis for the HER characterization. The result recorded the highest thickness of 9273.45 nm at 40 V anodizing voltage and the lowest surface roughness of 837.16 nm recorded at 50 V. The linear sweep polarization test solution exhibited the lowest overpotential at 50 V, 398.3 mV and a Tafel slope of 196 mVdec-1. These findings provide insight on the possibility of AC anodizing for improving the surface characteristics of SS304L for use in energy conversion applications.
  • Publication
    Characterization of porous anodic aluminium oxide film on aluminium templates formed in anodizing process
    (Universiti Malaysia Perlis (UniMAP), 2010-09-06) ;
    A porous anodic aluminium oxide (AAO) films were successfully fabricated on aluminium templates by using anodizing technique. The anodizing process was done in the mixed acid solution of phosphoric acid and acetic acid. The growth, morphology and chemical composition of AAO film were investigated. During the anodizing process, the growth of the oxide pores was strictly influenced by the anodizing parameters. The anodizing was done by varying the voltage at 70V to 130V and temperature from 5°C to 25°C. The electrolyte concentration was remaining constant. In this study, all the samples were characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. From this study, the optimum parameters to obtain porous AAO film with the mixture of phosphoric acid and acetic acid solution can be known.
  • Publication
    Corrosion behaviour of powder metallurgy aluminium matrix composite reinforced with alumina Saffilâ„¢ short fibre
    (Universiti Malaysia Perlis (UniMAP), 2010-09-06) ;
    Normah Che Man
    The corrosion behaviour of PM Al composite will be affected by the presence of alloying element and reinforcing phase in the composite. This study focused on magnesium and alumina Saffil™ short fibres reinforcement affected to corrosion behaviour of PM AMCs in 3.5wt% NaCl. PM Al composite and PM Al-Mg composite were fabricated from flaky aluminium powder, 2wt% granular magnesium and 15wt% alumina Saffil™ short fibres. The corrosion testing was done using potentiostat Gamry G300 to create Tafel plot and polarization curve. The corrosion effects were analyse using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). From experiment, pitting was localized surrounding the magnesium constituents which occur randomly throughout the surface of PM Al-Mg composite. XRD analysis revealed that aluminum oxide (δ-Al Al1.67O4), aluminium hydroxide (Al (OH)3) and aluminium oxide (α-Al2O3) phases were detected in oxide film. The corrosion current density (Icrit) of PM Al composite is lower than PM Al-Mg composite which is 2.0 x 10-1 A/cm2 and 4.0 x10-1 A/cm2, respectively. Magnesium is used as inhibitor in corrosion behaviour of PM Al-Mg composite have been changed and protected with a stable formation of oxide film. The corrosion resistance of PM Al-composite was decreased with the presence of alumina Saffil™ short fibres in composite due to discontinuities in oxide film provided the corrosion initiated in sample.
  • Publication
    The corrosion study of Co-Cr-Ni alloy fabricated by powder metallurgy
    (Universiti Malaysia Perlis (UniMAP), 2010-09-06)
    Raudhah Othman
    ;
    Shamsul Baharin Jamaludin
    ;
    Cobalt-based alloys have been widely used in biomedical application. In this research, various compositions of Co-Cr-Ni alloys were developed and produced by powder metallurgy route. This study was also aimed to investigate the corrosion behavior of Co-Cr-Ni alloys. The Co-Cr-Ni powders were first milled using planetary mill and compacted using uniaxial hand press to a pellet shape before being sintered using tube furnace. Immersion test was carried out in a water bath while maintaining the temperature of 37°C. Energy dispersive X-ray spectroscopy (EDS) was used for elemental analysis of the immersed samples. The result showed that sample with Co91Cr4Ni5 composition has the lowest mpy result after 30 days immersed in 0.9% sodium chloride solution while sample with Co57Cr20Ni23 composition recorded the highest mpy value.
  • Publication
    Microwave and electrical properties of SrTiO3 for DRA application
    (Universiti Malaysia Perlis (UniMAP), 2018-12)
    Norhizatol Fashren Muhamad
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    ; ; ;
    Mohd Faizal Jamlos
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    ;
    Appropriate level of dielectric constant and low dielectric loss are basic requirements for microwave device, especially in dielectric resonator antenna (DRA). In this paper, investigation with experimental studies of SrTiO₃ ceramic fabricated as cylindrical dielectric resonator antennas (CDRAs) was conducted. Ceramic powder was prepared using conventional solid state reaction method. X-ray Diffraction exposes physical properties SrTiO₃ which exhibit cubic structure. The electrical properties such as dielectric constant (εᵣ) and dielectric loss (tan δ) were studied in variation of temperatures and frequencies. At room temperature the dielectric constant SrTiO₃ is about 240. The dielectric loss obtain shows very low loss value roughly below 0.07. The return loss and bandwidth of CDRAs at their respective resonant frequencies are shown in this paper.