Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 3Novel Injectable Calcium-Magnesium Phosphate Cement-Based Composites With Piezoelectric Properties: Advancements in Bone Regeneration Applications(Springer, 2024) Sakar, Neslihan; Albayrak, Aylin Ziylan; Karakaya, Merve; Adem, Umut; Tansel, TunayDesigning a novel injectable bone cement is an important approach to the success of bone healing in minimally invasive surgeries. As natural bone has a piezoelectric property, which is crucial in bone regeneration, this study focused on the development of a novel injectable composite bone cement with piezoelectric properties. For the composite composition, calcium and zirconium doped barium titanate (BCZT) was used for its piezoelectric property, while calcium phosphate and magnesium phosphate cement (CMPC) were preferred for its bone-like properties. In this framework, first BCZT, CMPC, and their composites were prepared, and their phase structures, particle size distributions, and piezoelectric and dielectric properties were investigated. Then, the composite bone cements were prepared by mixing CMPC with BCZT in three different ratios (20%, 30%, and 40%). Next, polysorbate 80 solution was added to the cement mixtures to prepare the injectable pastes. Finally, injectability, setting time, and compressive strength of the composites were assessed. As a result, the composite bone cement containing 30% BCZT has the potential to be used as an injectable bone cement in invasive orthopedic surgery.Article Citation - WoS: 3Citation - Scopus: 3Effects of Different Precursors on the Aging and Electrocaloric Properties of Mn-Doped Ba0.95sr0.05tio3 Ceramics(Springer, 2023) Karakaya, Merve; Erdem, Emre; Akdoğan, Yaşar; Adem, UmutIn this study, the effects of different types of Mn precursors (MnO2 and Mn2O3) and sintering temperature on the defect dipole formation, ferroelectric aging and electrical properties were investigated by using Ba0.95Sr0.05TiO3 ceramics as the base. Both Mn precursors were substituted to the Ti-site as 1 mol% and two different sintering temperatures of 1325 and 1400 degrees C were used to study the effect of grain size. We deduced that slightly higher amounts of Mn2+ can be incorporated into the perovskite structure when MnO2 is used as the precursor, by using X-ray diffraction and electron paramagnetic resonance spectroscopy. Mn-doped samples sintered at 1325 degrees C age faster than those sintered at 1400 degrees C. Aging caused a decrease in the electrocaloric effect whereas Mn-doping increased it. This study shows that Mn precursor used for the acceptor doping affects the amount of Mn incorporated into the structure and therefore electrical properties of the resulting ceramics.Article Citation - WoS: 3Citation - Scopus: 4Development of Textured Lead-Free Nbt-Based Piezoelectric Materials in a Matrix, Synthesized by an Alternative Route, Via Templated Grain Growth(Springer, 2023) Çoban Tetik, Hatice Şule; Suvacı, Ender; Avcı, A. Murat; Adem, Umut; Karakaya, MerveIn this study, (1−x)(K0.5Bi0.5TiO3-BaTiO3)−xNa0.5Bi0.5TiO3 KBT:BT = 2:1 where x = 0.8 (KBT-BT-NBT) (001) textured lead-free piezoelectric ceramics were fabricated using BT template by templated grain growth with tape casting. Unlike the commonly used matrix preparation method, which is the calcination of all raw materials in one step, the matrix phase was prepared in a different way by first preparing KBT, BT and NBT powders separately and then by calcining the mixtures of these powders, so that effect of the matrix, synthesized by this alternative route, on texture development properties was evaluated. In addition, the effect of BT template content on the grain orientation with different sintering temperature and time, structure evolution, phase stability and piezoelectric properties were investigated to assess the materials’ actuating performance. The highest Lotgering factor of 81% was achieved for the textured ceramics with 10 wt% BT templates sintered at 1150 °C for 48 h. Compared to the one-step synthesis method, similar Lotgering factor values were obtained at lower sintering temperatures in the matrix, synthesized by the alternative 2-step method. The highest piezoelectric constant, remnant polarization, strain value and depolarization temperature were also obtained from the same sample, as ~ 190 pC/N, 30 kV/cm, 25% at 50 kV/cm and ~ 165 °C, respectively. The results show that the textured, lead free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 (KBT-BT-NBT) ceramics that are developed by using the matrix, synthesized by the alternative 2-step method, can be very promising lead-free electroceramics for high performance actuator applications.Article Citation - WoS: 11Citation - Scopus: 11Enhanced Room Temperature Energy Storage Density of Bi(li1/3ti2 Substituted Bi0.5na0.5tio3-Batio3 Ceramics(IOP Publishing, 2021) Karakaya, Merve; Adem, UmutFor high power electronics applications, relaxor ferroelectrics are promising materials due to their superior energy storage properties. In this study, we investigate the energy storage properties of novel lead free relaxor ferroelectric ceramics (1-x)(0.92Bi(0.5)Na(0.5)TiO(3)-0.08BaTiO(3))-xBi(Li1/3Ti2/3)O-3 (abbreviated as BNT-8BT-xBLT). BNT-8BT composition which is close to morphotropic phase boundary was chosen as the base due to its large maximum polarization (P-m) and higher ratio of weakly polar tetragonal phase which is expected to facilitate ergodic relaxor behavior and improve energy storage density. The substitution of BLT to the BNT-8BT strongly disrupts the correlations between the polar nanoregions and the transition from nonergodic to ergodic relaxor state occurs already at x = 0.02 BLT at room temperature. Largest energy density (W-rec) at 61 kV cm(-1) was obtained for x = 0.02 sample (0.656 J cm(-3)), followed by x = 0.03 (W-rec = 0.614 J cm(-3)) and x = 0.05 (W-rec= 0.559 J cm(-3)). The x = 0.02 sample keeps its energy storage density at high temperatures (i.e. W-rec= 0.88 J cm(-3,) eta = 97%, E-m= 65 kV cm(-1) at 125 degrees C), while larger electric field (up to 89 kV cm(-1)) could be applied to the x = 0.05 sample with the smallest grain size and energy density of 1.03 J cm(-3) was reached at room temperature. Energy storage density values of BLT substituted materials normalized per unit applied electric field are promising among BNT-based materials.