Yaldır, Onur; Karabiberoğlu, Şükriye; Koçak, Çağrı Ceylan; Yavuz, Emre; Özdokur, Kemal Volkan; Dursun, Zekerya

Composite materials formed by combining mixed metal oxides and graphitic carbon nitride have gained significant attention in recent years for energy applications. Here, a novel material was obtained by combining ZnV2O6 mixed metal oxide structure synthesized by the solvothermal method with g-C3N4 prepared by pyrolysis. SEM, XPS, XRD, FTIR, and TGA techniques were employed for comprehensive material characterization. The synthesized ZnV2O6/g-C3N4 was then used in supercapacitor studies. The resulting composite material demonstrated a specific capacity of 438 F g−1 at 1.5 A g−1 in 6.0 M KOH solution. After 2500 cycles, it retains 96 % of its capacitance, demonstrating excellent cyclic stability. Furthermore, a symmetric supercapacitor device based on ZnV₂O₆/g-C₃N₄ electrodes was assembled and tested, achieving high capacitance retention over extended charge–discharge cycles. The synergistic effect of g-C3N4, with its large surface area and chemical stability, and ZnV2O6, with its fast electron transfer ability, has resulted in the formation of the composite with enhanced performance.

Zulkimi, Muhammad Misbah Muhammad; Azis, Raba'ah Syahidah; Ismail, Ismayadi; Mokhtar, Nurhidayaty; Ertugrul, Mehmet; Hamidon, Mohd Nizar; Hasan, Intan Helina; Yesilbag, Yasar Ozkan; Tuzluca, Fatma Nur; Ozturk, Gokhan

A strategy of a highly feasible method to achieve a broad bandwidth of radar absorbing materials (RAM) is reported. Herein the magnetic Sr-hexaferrite were prepared using a conventional sintering process at 900 °C and later hybridized with coiled carbon nanotubes (CNT) via a chemical vapour deposition (CVD) method. X-ray diffraction (XRD) detected two phases of compounds after sintering which were 36 % of SrFe2O4 and 64 % of SrFe12O19. Two groupings of nanoparticle size showed no significant effect on reflection loss (RL) performance. Interestingly after hybridization of coiled CNT with the magnetic materials, the permittivity was increased tremendously hence enhancing the RL. Multiple relaxations of dielectric and eddy current losses were responsible for the enhancement. The RL was increased as the thickness was increased from 1 mm to 3 mm. 6 % of coiled CNT/Sr-hexaferrite hybrid resulted in low RL of -19 dB with the broadest bandwidth of 3GHz over X-band frequency. The report is important for paving future work in obtaining a desired broad bandwidth RAM.

Yetim, A.F.; Kovacı, H.; Kasapoğlu, A.E.; Bozkurt, Y.B.; Çelik, A.

DLC films are widely used in different engineering products. However, some problems such as inadequate toughness, insufficient adhesion and internal stresses affect their performance. Therefore, we aimed to enhance the mechanical and tribological features of Cp-Ti by metal-free and metal-doped DLC films in this study. Cp-Ti samples were coated with un-doped and Ti, Al and V metal-doped DLC films by PVD. Their properties were investigated by Raman, XPS, XRD, SEM and wear tester. The results revealed that the incorporation of metal in DLC increased the disorder. Ti, Al and V carbides formed on DLC due to bonding of doping elements with carbon. Metal-doping improved the adhesion and decreased the internal stresses and these improvements caused metal-doped films to exhibit better tribological properties than metal-free film.