Now showing 1 - 3 of 3
  • Publication
    Effect of kaolin geopolymer ceramics addition on the microstructure and shear strength of Sn-3.0Ag-0.5Cu solder joints during multiple reflow
    ( 2022)
    Nur Syahirah Mohamad Zaimi
    ;
    ; ; ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Mohd Izrul Izwan Ramli
    ;
    Kazuhiro Nogita
    ;
    Hideyuki Yasuda
    ;
    Ioan Gabriel Sandu
    Solder interconnection in three-dimensional (3D) electronic packaging is required to undergo multiple reflow cycles of the soldering process. This paper elucidates the effects of multiple reflow cycles on the solder joints of Sn-3.0Ag-0.5Cu (SAC305) lead (Pb)-free solder with the addition of 1.0 wt.% kaolin geopolymer ceramics (KGC). The samples were fabricated using powder metallurgy with the hybrid microwave sintering method. Apart from using conventional cross-sectioned microstructure imaging, advanced synchrotron real-time in situ imaging was used to observe primary IMC formation in SAC305-KGC solder joints subjected to multiple reflow soldering. The addition of KGC particles in SAC305 suppressed the Cu6Sn5 IMC’s growth as primary and interfacial layers, improving the shear strength after multiple reflow soldering. The growth rate constant for the interfacial Cu6Sn5 IMC was also calculated in this study. The average growth rate of the primary Cu6Sn5 IMCs decreased from 49 µm/s in SAC305 to 38 µm/s with the addition of KGC particles. As a result, the average solidified length in the SAC305-KGC is shorter than SAC305 for multiple reflow soldering. It was also observed that with KGC additions, the growth direction of the primary Cu6Sn5 IMC in SAC305 changed from one growth to two growth directions. The observed results can be attributed to the presence of KGC particles both at grains of interfacial Cu6Sn5 IMCs and at the surface of primary Cu6Sn5 IMC.
  • Publication
    Development of coconut fiber reinforced cement composites with the addition of fly ash
    (Universiti Malaysia Perlis (UniMAP), 2012)
    This research was conducted to study the coconut fiber reinforced cement composites with the addition of fly ash in cement panel. Ordinary Portland cement, coconut fiber, fly ash, sand and water were the main raw materials used in this project. The development of coconut fiber reinforced cement composites was carried out by substituting fly ash to portion of sand based on its ratio. in this study, the ratio used to the mixture were 1 : 0.2 : 0.8: 0.03, 1 : 0.2: 0.8 : 0.06, 1: 0.2 : 0.8: 0.09, 1 : 0.2 : 0.8 : 0.12, 1 : 0. 2 : 0. 8 : 0.15 (cement : fly ash : sand : coconut fiber) . The water to cement ratio were varied regarding to the fiber content. The sizes of the sample tested were, 160 mm x 40 mm x 40 mm for compression test while 100 mm x 100 mm x -10 mm for density, moisture content and water absorption tests. The samples were cured for 7 days, 14 days and 28 days respectively in water. The result indicates that the cement composites with 9 wt. % of coconut .fiber gives the high value of compressive strength and modulus ofrupture while 20 wt. %of fly ash and 80 wt. %sand was found to be a suitable ratio for this cement composites. It was observed that, increasing fiber content will decrease the density while moisture content and water absorption percentages were increased.
  • Publication
    Effect of Sn Doping on the Curie Temperature, Structural, Dielectric and Piezoelectric Properties of Ba0.8Sr0.2Ti1−xSnxO3 Ceramics
    ( 2023-11-01)
    Nasir N.N.
    ;
    ; ;
    Muhsen K.N.D.K.
    ;
    ; ;
    Jumali M.H.H.
    ;
    Jamil N.H.B.
    Ba0.8Sr0.2Ti1−xSnxO3 material with varying Sn concentrations (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10) was synthesized using the conventional solid-state reaction method. X-ray diffraction (XRD) analysis reveals that as the Sn concentration increases from x = 0 to x = 0.10, the Ba0.8Sr0.2Ti1−xSnxO3 undergoes a structural phase change from tetragonal to cubic. Dielectric analysis of Ba0.8Sr0.2Ti1−xSnxO3 shows a significant drop in Tc, from 65 to 5°C, caused by the replacement of Sn4+ ions with larger ionic radii compared to Ti4+ ions at the B-sites. The composition with x = 0 exhibits the largest dielectric constant due to its enormous spontaneous dipole moments. Conversely, the substitution of Sn in Ba0.8Sr0.2Ti1−xSnxO3 reveals a decrease in the dielectric constant at the B-site structure of perovskite, resulting in a reduced tolerance factor and a decrease in the tetragonality of the sample. However, the pinching effect significantly enhances the dielectric constant of the sample with x = 0.10. Grain size measurements for x = 0 demonstrate a well-distributed grain structure. Additionally, the undoped sample exhibits a higher piezoelectric constant than the Ba0.8Sr0.2Ti1−xSnxO3 samples. According to the piezoelectric constant data, the composition with a tetragonal structure appears to have a greater piezoelectric constant than the cubic structure.
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