Yazar "Mohamad, Ahmad Azmin" seçeneğine göre listele

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    Effect of TiO2 nanoparticles on the horizontal hardness properties of Sn-3.0Ag-0.5Cu-1.0TiO2 composite solder
    (Elsevier Sci Ltd, 2019) Nasir, Siti Shareeda Mohd; Yahaya, Muhamad Zamri; Erer, Ahmet Mustafa; Illes, Balks; Mohamad, Ahmad Azmin
    The improvement in the hardness of Sn-3.0Ag-0.5Cu solder alloy reinforced with 1.0 wt % TiO2 nanoparticles was evaluated by nanoindentation. A specific indentation array was performed on four different horizontal cross sections of the composite solder with different heights and diameters, in order to verify the mixing homogeneity of TiO2 nanoparticles within the Sn-3.0Ag-0.5Cu solder paste during the ball milling process. The phase analysis indicated successful blending of the Sn-3.0Ag-0.5Cu with the TiO2 nanoparticles. According the scanning electron microscopy micrographs, presence of the TiO2 nanoparticles reduced the size of the Cu6Sn5 and Ag3Sn intermetallic compound phases. Incorporation of the 1.0 wt % TiO2 nanoparticles improved the hardness values up to 26.2% than that of pure SAC305. The hardness values increased gradually from the top cross sections towards adjacent to the solder/substrate interface. The mechanism of the hardness improvement attained by the TiO2 nanoparticles addition were also investigated on the horizontal cross sections of the samples.
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    Selective electrochemical etching of the Sn-3Ag-0.5Cu/0.07 wt% graphene nanoparticle composite solder
    (Elsevier, 2021) Ahmad, Ibrahym; Nazeri, Muhammad Firdaus Mohd; Salleh, Nor Azmira; Kheawhom, Soorathep; Erer, Ahmet Mustafa; Kurt, Adem; Mohamad, Ahmad Azmin
    The morphological changes of SAC305 solder alloy with the addition of 0.07 wt% graphene was investigated using selective electrochemical etching. To evaluate the effect of graphene inclusion, selective electrochemical removal of the beta-Sn phase from SAC305 and SAC305/0.07GNP was performed using a standard three-electrode cell approach at specific potentials determined by cyclic voltammetry. The phase, chemical structure and microstructural changes were observed. The texture and the phases of SAC305 solder paste were retained, while the microstructure of beta-Sn and Ag3Sn was refined owning to graphene addition. Sufficient removal of beta-Sn without affecting other phases was obtained by using etching potential below -350 mV. Due to Van der Waals force attraction, two types of agglomeration of graphene were observed from cross-sectional observation. Large agglomerations seen at the vicinity of solder/substrate interface were found to help in forming diffusion barrier. This contributes to the refinement of microstructure with the presence of graphene. Accurate observation regarding the shape and texture of the intermetallic compound (IMC) phases affected by the addition of graphene provided by selective electrochemical removal helps better insight into understanding the electrochemical dissolution mechanism of SAC alloys. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.