Now showing 1 - 10 of 29
  • Publication
    Effect of temperature and amount of Ag on TiO₂ thin film synthesised via sol–gel method
    TiO₂ sol was produced via the sol–gel method with different amounts of AgNO₃ as the source of Ag. The Ag/TiO₂ thin film was obtained by spin coating and was annealed at various annealing temperatures (300°C, 400°C and 500°C) for 1 h. The effect of different amounts of AgNO₃ and different annealing temperatures on the TiO₂ thin films was studied by characterising the phase composition, surface morphology and water contact angle. Results from the x-ray diffraction (XRD) pattern show that with the addition of AgNO₃, Ag/TiO₂ can be formed at low annealing temperatures (300°C). At increased annealing temperatures (400°C and 500°C) and amounts of AgNO₃ (1.0 ml and 1.5 ml), Ag₂O and Ag₃O4 phases were observed. Flakes or flaky islands were formed on the thin film due to thermal expansion mismatch between the film and substrate, residual stress within the film or the release of volatile species when annealed at a low temperature of ⁓300°C. Increasing the temperature to 500°C resulted in the growth and coalescence of the flaky islands by the surface diffusion of adsorbed atoms (adatoms) and their annexation to the surface of existing nuclei. The water contact angle provides valuable insight into the surface interactions between water droplets and the surface of Ag/TiO₂ thin films. It was found that at 1.5 ml AgNO₃, the increased annealing temperature from 300°C to 500°C decreased the water contact angle of Ag/TiO₂ thin films from 83.86° to 34.62°, forming superhydrophilic properties, which indicated its excellent potential as a photocatalyst.
  • Publication
    Enhancement of Power Conversion Efficiency with Zinc Oxide as Photoanode and Cyanococcus, Punica granatum L., and Vitis vinifera as Natural Fruit Dyes for Dye-Sensitized Solar Cells
    ( 2022-11-01) ; ; ;
    Jamalullail N.
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    ; ;
    Sandu A.V.
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    Baltatu M.S.
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    Vizureanu P.
    Ruthenium N719 is a well-known material used as the dye in commercial dye-sensitized solar cell (DSSC) devices. However, it poses risks to human health and the environment over time. On the other hand, titanium dioxide (TiO2) has low electron mobility and high recombination losses when used as a photoanode in this photovoltaic technology device. In addition, using Ruthenium as the dye material harms the environment and human health. As an alternative sensitizer to compensate Ruthenium on two different photoanodes (TiO2 and ZnO), we constructed DSSC devices in this study using three different natural dyes (blueberry, pomegranate, and black grape). In good agreement with the anthocyanin content in the fruits, black grape, with the highest anthocyanin content (450.3 mg/L) compared to other fruit dyes (blueberry—386.6 mg/L and pomegranate—450.3 mg/L), resulted in the highest energy conversion efficiency (3.63%) for the natural dye-based DSSC. Furthermore, this research proved that the electrical performance of natural dye sensitizer in DSSC applications with a ZnO photoanode is better than using hazardous Ru N719 dye with a TiO2 photoanode owing to the advantage of high electron mobility in ZnO.
      1  31
  • Publication
    Thermal behaviour and microstructural analysis of Sn-40Pb alloy and Sn-40Pb soldered on electroless nickel/immersion gold
    Due to the toxicity of lead solder, the lead-free solder has been developing and improved in order to replace the lead solder. However, the behaviour and properties of lead solder is still better than the lead-free solder, especially in application when soldering on substrate. Hence, a common lead solder, Sn-40Pb is studied in this research by comparing with Sn-40Pb soldering on electroless nickel/immersion gold (ENIG) substrate. The thermal behaviour by differential scanning calorimeter (DSC) and microstructure formation with elemental analysis by scanning electron microscope (SEM) were carried out for Sn-40Pb solder alloy and Sn-40Pb soldered on ENIG substrate in this study. The result showed that the pasty range of Sn-40Pb was lower than Sn-40Pb/ENIG while the undercooling was higher. The diffusion and dissolution of Ni and Cu elements from ENIG substrate into the solder, forming the lead-rich phase with Ni elements and interfacial (Cu,Ni)6Sn5 with Pb elements in Sn-40Pb/ENIG. The diffusion and dissolution of elements from substrate into the solder affects the thermal behaviour and microstructural of solder.
      30  3
  • Publication
    Factors of Controlling the Formation of Titanium Dioxide (TiO2) Synthesized using Sol-gel Method - A Short Review
    ( 2022-01-24)
    Abdul Razak K.
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    ; ; ;
    Mahmed N.
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    Azani A.
    ;
    Chobpattana V.
    There have been experiments on TiO2 thin films synthesized utilizing sol-gel techniques. The sol-gel method is a straightforward technology that gives numerous benefits to the researcher, for instance, material's reliability, reproducibility, and controllability. Following from there, it can be utilized to make high-quality nano-structured thin films. According to previous studies, the TiO2 films' characteristics occur to be highly dependent on the production parameters and initial materials utilized. Controlling the formation of TiO2 thin films with the sol-gel method was momentarily discussed here.
      1  25
  • Publication
    Microstructure evolution of Ag/TiO₂ thin film
    ( 2021) ; ; ;
    Mohd Izrul Izwan Ramli
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    ; ;
    Kazuhiro Nogita
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    Hideyuki Yasuda
    ;
    Marcin Nabiałek
    ;
    Jerzy J. Wysłocki
    Ag/TiO₂ thin films were prepared using the sol-gel spin coating method. The microstructural growth behaviors of the prepared Ag/TiO₂ thin films were elucidated using real-time synchrotron radiation imaging, its structure was determined using grazing incidence X-ray diffraction (GIXRD), its morphology was imaged using the field emission scanning electron microscopy (FESEM), and its surface topography was examined using the atomic force microscope (AFM) in contact mode. The cubical shape was detected and identified as Ag, while the anatase, TiO₂ thin film resembled a porous ring-like structure. It was found that each ring that coalesced and formed channels occurred at a low annealing temperature of 280 °C. The energy dispersive X-ray (EDX) result revealed a small amount of Ag presence in the Ag/TiO₂ thin films. From the in-situ synchrotron radiation imaging, it was observed that as the annealing time increased, the growth of Ag/TiO₂ also increased in terms of area and the number of junctions. The growth rate of Ag/TiO₂ at 600 s was 47.26 µm2/s, and after 1200 s it decreased to 11.50 µm2/s and 11.55 µm2/s at 1800 s. Prolonged annealing will further decrease the growth rate to 5.94 µm2/s, 4.12 µm2/s and 4.86 µm2/s at 2400 s, 3000 s and 3600 s, respectively.
      3  17
  • Publication
    Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film
    In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.
      1
  • Publication
    Microstructural studies of ag/tio2 thin film; effect of annealing temperature
    ( 2022-01-01)
    Kamrosni A.R.
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    Azliza A.
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    ; ; ;
    Chobpattana V.
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    Kaczmarek L.
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    Jez B.
    ;
    Nabialek M.
    Microstructures are an important link between materials processing and performance, and microstructure control is essential for any materials processing route where the microstructure plays a major role in determining the properties. In this work, silverdoped titanium dioxide (Ag/TiO2) thin film was prepared by the sol-gel method through the hydrolysis of titanium tetra-isopropoxide and silver nitrate solution. The sol was spin coated on ITO glass substrate to get uniform film followed by annealing process for 2 hours. The obtained films were annealed at different annealing temperatures in the range of 300°C-600°C in order to observe the effect on crystalline state, microstructures and optical properties of Ag/TiO2thin film. The thin films were characterized by X-Ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectrophotometry. It is clearly seen, when the annealing temperature increases to 500°C, a peak at 2θ = 25.30° can be seen which refers to the structure of TiO2tetragonal anatase. The structure of Ag/TiO2thin film become denser, linked together, porous and uniformly distributed on the surface and displays the highest cut-off wavelength value which is 396 nm with the lowest band gap value, which is 3.10 eV.
      1
  • Publication
    Pengenalan kepada ujian bahan tanpa musnah
    Pengenalan Kepada Ujian Bahan Tanpa Musnah merupakan sebuah buku yang membincangkan beberapa perkara asas yang penting dalam ujian tanpa musnah. Ia meliputi kebanyakan kaedah ujian tanpa musnah yang sering digunakan di industri. Buku ini memberi penerangan dalam ujian bahan tanpa musnah yang sering digunakan dalam industri bagi memeriksa kecacatan atau ketidaksempurnaan sesuatu bahan tanpa merosakkan atau memusnahkan bahan yang diperiksa. Keseluruhan kandungan buku ini merangkumi perbincangan dari aspek teori serta konsep pengujian, kaedah pengujian, dan aplikasi ujian dalam industri.
      2  939
  • Publication
    The effect of thermal annealing on the microstructure and mechanical properties of Sn-0.7Cu-xZn solder joint
    The microstructural properties of a Pb-free solder joint significantly affect its mechanical behaviours. This paper details a systematic study of the effect of the annealing process on the microstructure and shear strength of a Zn-added Sn-0.7Cu solder joint. The results indicated that the IMC layer’s thickness at the solder/Cu interface increases with annealing time. The interfacial IMC layer of the Sn-0.7Cu solder joint gradually thickened with increasing annealing time and annealing temperature, while the interfacial IMC layer’s morphology changed from scallop-type to layer-type after the annealing process. However, the addition of 1.0 wt.% and 1.5 wt.% Zn in the Sn-0.7Cu effectively altered the interfacial IMC phase to Cu-Zn and suppressed the growth of Cu3Sn during the annealing process. The single-lap shear tests results confirmed that the addition of Zn decreased the shear strength of Sn-0.7Cu. The interfacial IMC of the Cu6Sn5 phase in Sn-0.7Cu changed to Cu-Zn due to the addition of Zn. The shear fractures in the annealed solder joint were ductile within the bulk solder instead of the interfacial IMC layer. Increased annealing time resulted in the increased presence of the Cu-Zn phase, which decreased the hardness and shear strength of the Sn-0.7Cu solder joint.
      2  19
  • Publication
    Microstructural Study on Ag/TiO2 Thin Film
    ( 2022-07-01)
    Razak K.A.
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    Azani A.
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    ; ;
    Mahmed N.
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    Chobpattana V.
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    Kaczmarek L.
    ;
    Sandu A.V.
    ;
    Garus S.
    The synthesis of Ag/TiO2 thin film was carried out by the sol–gel spin coating method using ITO glass as a substrate in a short period of stirring time, which is less than 25 min. The produced films were annealed in a furnace at 500◦C for 1 h. Various concentrations of AgNO3, from 0.1 to 0.9 M, were added. The as-prepared films were characterized using X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results indicate that all films showed a single phase of anatase, TiO2. Ag/TiO2 thin films with 0.1 M of AgNO3 solution show that the elements form networks connecting Ag/TiO2 microstructures forming a porous, consistent, and continuous layer on the substrate surface.
      2