Dielectric Properties of Calcium Phosphate Ceramics

Calcium phosphate ceramics with various Ca/P ratios of 1, 2, 3, 4 and 8 were synthesized via sol-gel route. The effects of Ca/P molar ratio on structural, morphological, dielectric and antimicrobial properties were investigated in detail using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and dielectric measurements. The Ca/P molar ratio significantly affects the crystal structure and phase composition. The crystallite size, lattice parameters and volume of the unit cell were remarkably affected by the change in the Ca/P molar ratio. The microstructure is changed with increasing the Ca/P molar ratio. The relative permittivity and alternating current conductivity gradually decrease for the samples having the Ca/P ratios higher than 2. The dielectric loss decreases gradually with the increase of the molar ratio of Ca/P.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7222</p

Investigation of the Structural, Thermal, Spectroscopic, and Electronic Properties of Praseodymium-based Hydroxyapatites Co-doped with Silver and Zinc in Varying Concentrations

This study investigates the crystal structure, energy gap, band structure, spectroscopy, thermal, and electrical properties of Pr3+-based hydroxyapatites (HAp) co-doped with Zn2+ and Ag+ in varying concentrations. The synthesized samples, designated as 0.25Zn-0.25Pr-HAp, 0.50Zn-0.25Pr-HAp, 0.75Zn-0.25Pr-HAp, 0.25Ag-0.25Pr-HAp, 0.50Ag-0.25Pr-HAp, and 0.75Ag-0.25Pr-HAp, were prepared using a wet chemical method. The materials were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Additionally, theoretical calculations employing density functional theory (DFT) were conducted to analyze the band structure (BS), energy gap (Eg; EHOMO-ELUMO), and density of states (DOS). Results revealed a progressive reduction in the bandgap with increasing dopant concentrations, particularly in Ag-doped samples. Notably, 0.75Ag-0.25Pr-HAp exhibited the smallest bandgap of 3.983 eV, indicating enhanced electronic conductivity and potential applications in bioelectronics and medical sensors. Furthermore, the co-doped samples demonstrated reduced crystallinity, larger crystallite sizes, and excellent stability in biological environments, alongside superior biocompatibility and antibacterial properties. Among the synthesized materials, 0.75Ag-0.25Pr-HAp exhibited promising characteristics as a biomedical material for bone-related applications, owing to its structural stability, enhanced electrical properties, and suitability in antibacterial and bioelectronic devices. This investigation highlights the versatility of Zn/Ag co-doped Pr-HAp materials for advanced biomedical and technological applications

Crystallinity Improvement of Co3O4 by Adding Thiourea

Tricobalt tetraoxide (Co3O4) samples having different thiourea/Co molar ratio of 0, 5 and 10 were prepared by wet chemical synthesis. The effects of thiourea content on the crystal structure-related parameters of Co3O4 were determined. The increase in the amount of thiourea caused a gradual decrease in the lattice parameters and specific surface area and an increase in the crystallinity and crystallite size. The experimental analysis results showed that thiourea content can be used to control the crystal structure-related parameters of Co3O4

Synthesis and Structural Characterization of Y-doped Pyramidal ZnO Powders

The present study focuses on the structural changes in ZnO powder induced by doping of a rare earth metal of Y. For this aim, we synthesized four ZnO samples with different Y-content using the combustion reaction method. X-ray powder diffraction (XRPD) technique and scanning electron microscopy (SEM) results confirm that the as-investigated structural parameters and morphology of the ZnO structure were affected directly by the concentration of Y dopant. For each Y-doped sample, randomly-oriented pyramidal morphology and the formation of a minority phase of Y2O3 were observed. A gradual increase in both lattice parameters and unit cell volume was detected with increasing Y content. All samples were found to be thermally stable in the temperature interval of 25-950 °C

Ni Katkısının Fe2O3’ün Yapısal Özellikleri Üzerine Etkilerinin Araştırılması

Sunulan çalışmada, Ni katkısının yaş kimyasal yöntemle hazırlanan Fe2O3’ün yapısal özellikleri üzerine etkileri X-ışını kırınımı (XRD), Fourier dönüşümlü kızılötesi (FTIR), diferansiyel termal analiz (DTA), termogravimetrik analiz (TGA) ve taramalı elektron mikroskopisi (SEM) teknikleri kullanılarak araştırıldı. XRD ve FTIR sonuçları her bir numune için Fe2O3 yapının oluşumunu destekledi. 4at.%Ni katkısına kadar yeni bir faz oluşumu gözlenmedi ve bu numune için NiO ikincil fazının oluşumu tespit edildi. Kristal yapı ilişkili parametreler ve morfoloji, Ni içeriğinden etkilendi. Özetle Ni, Fe2O3 yapının bazı özelliklerini kontrol etmek için kullanılabilir