WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Author: search.filters.author.Balcı-Çağıran,Ö.Publisher: search.filters.publisher.Elsevier Ltd

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 8
    High Entropy (hftizrvnb)b2 Ceramic Particulate Reinforced Al Matrix Composites: Synthesis, Mechanical, Microstructural and Thermal Characterization
    (Elsevier Ltd, 2024) Süzer,İ.; Özçakıcı,Y.E.; Tekinşen,A.S.; Bayrak,K.G.; Mertdinç-Ülküseven,S.; Balcı-Çağıran,Ö.; Ağaoğulları,D.
    This study aims to introduce a novel type of particulate reinforced Al matrix composite. High entropy (HfTiZrVNb)B2 ceramic particulate reinforced Al matrix composites were produced via a combined process of different powder metallurgy methods. Firstly, boride compounds (HfB2, TiB2, ZrB2, VB2, NbB2) were synthesized in the laboratory scale using the related metal oxide, boron oxide, and magnesium by mechanochemical synthesis (MCS) and leaching processes under optimum conditions. Secondly, the synthesized and purified boride powders were mixed in equimolar ratios using a planetary ball mill for 72 h, and they were sintered at 2000 °C under 30 MPa via spark plasma sintering (SPS). Thirdly, equimolar high entropy (HfTiZrVNb)B2 bulks were crushed, converted into powder forms, and added into Al powders at different amounts as 1, 2, 5, 10, and 15 wt %. Lastly, these powder blends were mechanically alloyed in a vibratory ball mill for 6 h, cold pressed and pressureless sintered at 630 °C for 2 h. For characterization techniques, X-ray diffractometry (XRD), thermal analysis, scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), density measurements using pycnometer and Archimedes' methods, microhardness and dry sliding wear tests were conducted on the sintered composites. The highest hardness (∼1.5 GPa) and the lowest wear rate (∼0.0012 mm3/Nm) were obtained in the Al-15 wt % (HfTiZrVNb)B2 sample. © 2024 Elsevier Ltd and Techna Group S.r.l.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 8
    Enhanced Performance and Cycling Behavior in Symmetric Supercapacitors Developed by Pure Hfb2 and Hfb2-Sic Composites
    (Elsevier Ltd, 2024) Paksoy,A.; Yıldırım,İ.D.; Arabi,S.; Güngör,A.; Erdem,E.; Balcı-Çağıran,Ö.
    Boron-based materials have attracted growing interest as promising candidates for energy storage applications. This study focuses on synthesizing pure HfB2 powders through a straightforward method involving the mechanical activation of a powder mixture comprising hafnium tetrachloride (HfCl4), boron (B), and magnesium (Mg). The HfB2 powders were mechanically alloyed with varying amounts of SiC powders to create HfB2-based composite structures. The chemical and microstructural properties of the synthesized samples were assessed using XRD, SEM/EDX, and DLS characterization techniques. Supercapacitor device performances of all resulting powders as symmetrical electrodes were systematically investigated. The test results revealed that the pure HfB2 electrode material exhibited a pseudocapacitor behavior, whereas composite powders exhibited battery-like behavior. Composite powders, demonstrated enhanced supercapacitor performance surpassing that of pure powder in terms of energy density and cycle efficiency. The pure HfB2 electrode displayed the highest power density (95 Wkg−1) among all samples: Its distinctive pseudocapacitor behavior results in the highest power density, providing valuable insights into the intricate relationship between composition and electrochemical performance in boron-based supercapacitor materials. Moreover, these results propose that by synthesizing composite powders, the charge storage mechanism can be altered and used to improve the energy density. © 2024 Elsevier B.V.