Kobalt iyonu katkılamasının magnezyum ortoborat seramik tozlarının sentezi ve yapısı üzerindeki etkisinin araştırılması

In this thesis, the synthesis of undoped and cobalt ion doped nanosized magnesium orthoborate ceramic powders was carried out via conventional solid state synthesis technique. Cobalt-containing magnesium orthoborates were prepared using Mg(NO3)2.6H2O, 5% excess H3BO3 and cobalt nitrate Co(NO3)2.6H2O as starting materials. Different concentrations of cobalt metal ion were used to obtain the kotoite type of magnesium orthoborate given within the formula Mg3-xCox(BO3)2 (x: 0.005, 0.01, 0.025, 0.05, 0.075, 0.500, 1.000, 1.500, 2.000, 2.500). The impact of different concentrations of cobalt metal on the structural features of the synthesized products was examined by the XRD technique. When the XRD data were examined, it was observed that in the kotoite structured borate materials obtained in the orthorhombic crystal system at 900oC, the low amount of Co(II) ion added did not cause any change in the crystal structure of the kotoite. However as the cobalt ion content increased, the formation of cobalt orthoborate (Co₃(BO₃)₂) has became evident. Additionally, FTIR analysis revealed that all the characteristic bands of orthoborates were observed between 2000–500 cm− 1. According to the DRS studies, the absorbance spectra of all compounds showed two bands at 250 and 335 nm. It has been observed that the UV band positions for cobalt containing magnesium orthoborate samples slightly shift to the different wavelengths in comparison with the pure Mg3(BO3)2. In addition, the thermal properties of cobalt-containing kotoite-type magnesium orthoborate ceramic powders were examined using TG/DTA techniques, and the presence of an endothermic peak around 1390°C was detected for all orthoborate products prepared in this study.