prvi kongres hrvatskih znanstvenika iz domovine i inozemstva - HATZ

PRVI KONGRES HRVATSKIH ZNANSTVENIKA IZ DOMOVINE I INOZEMSTVAZagreb - Vukovar, 15. - 19. studenog 2004.P - 36NANOSTRUCTURED TiO 2 - MECHANOCEMICAL PREPARATION,CHARACTERISATION AND SINTERINGGajović, A., Tomašić, N., Musić, S.Faculty of Science, University of Zagreb, CroatiaNanostructured TiO2 was prepared by high-energy ball milling at different condition. Thesamples were sintered at high temperatures to investigate its behavior during sinteringand properties of final product. Structural changes induced in the sample during thepreparation were monitoring by Raman spectroscopy. The changes of the particledimension were monitored by transmission electron microscopy (TEM) and electrondiffraction. Starting material and prepared nanostructured material, achieved byprolonged ball-milling, were additionally studied by X-ray powder diffraction. The sinteringprocesses were performed in argon and monitored at high temperature in situ by Ramanspectroscopy. The cooled materials were also investigated by scanning electronmicroscopy. A different milling time induced sequence of phase transitions, from anatasethrough high-pressure TiO2 II phase to rutile and prolonged milling decreased the particleto nanometric sizes. The rate of phase transition and diminution, along with purity ofnanoparticles TiO2, depended on powder-to-ball weight ratio. X-ray powder diffraction ofTiO2, obtained for prolonged ball-milling, showed the same structure as Ramanspectroscopy, but it was much accurate for determination of sample contamination due towearing of milling media. The crystallite sizes, determined from bordering of diffractionlines, were in agreement with particles sizes obtained by TEM of milled TiO2. Duringsintering of nanosized TiO2 the amorphisation was noticed at lower temperature inrelation to the sintering of micron-size TiO2. Sintered samples had smaller grain sizes.The ball-milling was shown to be a simple method for preparation of nanostructured TiO2.Such prepared TiO2 nanoparticles can be good candidate for preparation ofnanoceramics.Presented on:Autumn School on Materials Science and Electron Microscopy, "New developments innanostructured materials - synthesis, characterization, functionality”Berlin, Germany, 2003.Principal Investigator : Dr.sc. Vladimir BermanecProject No. 011942040