AnaStankovic-MT.pdf - Institut tehniÄkih nauka SANU

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Univerzitet u Beogradu, Fakultet za fizičku hemijuAna StankovićABSTRACTCeramic nanostructured materials, such as zinc oxide, ZnO, and zirconium dioxide,ZrO 2 , have a great potential for the application in various areas of industrial productionprimarily due to their nanosized particles. In conventional methods of synthesis such as solgelprocessing, precipitation from the solution, hydrothermal synthesis, spray pyrolysis, etc.,very often, it is not possible to overcome problems posed by powder particle agglomeration.Mechanochemical synthesis gives excellent results in obtaining nanostructured materials. Ithas been widely applied for preparation of large variety of materials composed of highlydispersed nanosized particles.In the experiments presented in this thesis, mechanochemical synthesis was used toobtain nanostructured ZnO and ZrO 2 powders. We examined the influence of differentprocessing parameters (milling time, calcination temperature) on the course of the synthesis.Special attention was paid to the study of the impact of different types of inorganic andorganic compounds used as PCA (process controlling agent) on the morphology anddimensions of synthesized ceramic particles. In all experiments, we used planetary ball-mill,Retsch PM4, agate jars and alumina balls. Mechanical treatment time varied from 30 min to 8h. NaCl was used in the synthesis of ZrO 2 powder as an inorganic PCA, whereas in thesynthesis of ZnO powder we used CaCl 2 . Oxalic acid (C 2 H 2 O 4·2H 2 O) was used as an organicPCA in the synthesis of ZnO powder. Calcination temperature ranged in the interval of 300-800 °C.The smallest particle sizes, varying between 50 and 90 nm, and the best particle sizeuniformity were obtained in the ZnO powder sample mechanochemically treated for 4 h, inwater solution of oxalic acid (C 2 H 2 O 4·2H 2 O) aq as PCA, calcinated for 1 h at 450 °C. Particleagglomeration was almost completely prevented.Powder samples were characterized using X-ray powder diffraction (XRPD),Scanning electron microscopy (SEM), Field emission microscopy (FE SEM), Differentialthermal analysis (DTA) and Thermogravimetric analysis (TG).8
Univerzitet u Beogradu, Fakultet za fizičku hemijuAna Stanković1 Teorijski deo9
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