Aliye Arabaci

Investigation of Microstructural Properties of Sm_{0.1}Ce_{0.9}O_{1.95} Powders

Ceria doped with rare earth oxides such as Gd\(_{2}\)O\(_{3}\), Sm\(_{2}\)O\(_{3}\) has been considered as one of the most promising candidate materials as electrolyte materials for intermediate temperature solid oxide fuel cells. Samarium doped ceria, Sm\(_{0.1}\)Ce\(_{0.9}\)O\(_{1.95}\) (SDC), powders are successfully prepared by Pechini method using ethylene glycol, citric acid, cerium nitrate and samarium nitrate as the starting materials. Crystal structure and microstructure were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The sintered SDC samples at 1400 \(^{\circ }\)C had dense structure (98 % of the theoretical density).

Microstuctural and Mechanical Properties of Zirconia-Silica-Hydroxyapatite Composite for Biomedical Applications

Hydroxyapatite is a calcium phosphate ceramic that is used as a biomaterial. It has been studied extensively as a candidate biomaterial for prosthetic applications. Hydroxyapatite (HA) does not have the mechanical strength to enable it to succeed in long term load bearing applications. Therefore, Its mechanical properties may be improved with addition of zirconia powders. The aim of this study is to improve the mechanical properties of the hydroxyapatite by producing composite material including zirconia and silica powders. Therefore, hydroxyapatite was mixed with 5 wt% zirconia, 5 wt% silica powders and then this pressed mixture were sintered at different temperatures (1100-1300°C). The sintering behavior, microstructural characteristics and mechanical properties were investigated.

High Temperature - FTIR Characterization of Gadolinia Doped Ceria

Doped ceria-based (DC) materials have recently been considered as the most promising solid electrolytes for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. Doped ceria is usually prepared via thermal decomposition of its water soluble salts, especially, acetates and nitrates. The properties of the obtained final product directly influenced by the starting material and the decomposition products. Therefore, it is crucial to understand the decomposition steps and intermediate products. Number of experimental work have been reported using various in-situ and ex-situ techniques such as thermogravimetry with mass spectrometry (TG/DTA-MS), X-ray diffraction with differential scanning calorimeter (XRD-DSC). However, the available literature data is limited and not reasonably in agreement with each other. High Temperature FT-IR spectroscopy, TG/DTA-MS, XRD, techniques were used and results are compared with literature. A good agreement between the thermal analyses and HT-FTIR results were obtained. Possible decomposition mechanism is discussed.