Automatska mikrostrukturna analiza sinterovanih materijala

In this article the new approach to automatic microstructure analysis of the sintered materials has been presented. The method is based on contour recognition and decomposition of digital image, according to their gray scale intensity and the use of log-hyperbolic grain size distribution and it has been successfully applied on microstructure analysis of BaTiO3 sintered under non isothermal conditions.U ovom radu je prezentovana nova metoda za automatsku mikrostrukturnu analizu materijala. Metoda je bazirana na prepoznavanju kontura i dekompoziciji digitalne slike na osnovu fotometrijskih zakona, kao i na primeni log hiperbolične distribucije. Ova metoda je uspešno primenjena za mikrostrukturnu analizu neizotermski sinterovanog barijum-titanata

Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3

Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples.Prah barijum-titanata je mehanički aktiviran u planetarnom mlinu sa kuglicama 60 i 120 minuta. Neizotermsko sinterovanje neaktiviranog i aktiviranih uzoraka proučeno je u dilatometru u temperaturskom intervalu od sobne do 1380oS sa tri različite brzine zagrevanja (10, 20 i 30oS/min). Mehanizmi ranih stadijuma sinterovanja su analizirani za sva tri tipa uzoraka i uočene su značajne razlike između neaktiviranih i mehanički aktiviranih uzoraka

TiO2 based nanomaterials and nanostructures for green convergent technologies and environmental protection

Imajući u vidu značaj razvoja naprednih nanomaterijala za zaštitu prirodne okoline, u ovome radu su prezentovane primene nanomaterijala i nanostruktura na bazi TiO2 u oblastima obnovljivih izvora energije, hemijske i bio dekontaminacije. Objašnjena je uloga TiO2 u formiranju kompozitnih hibridnih struktura za prikupljanje solarne energije, kao i primena različitih antimikrobnih materijala na bazi TiO2 koji se koriste za fotokatalitičko uklanjanje polutanata. Naročita pažnja je posvećena strukturi i svojstvima titan dioksidnih nanotuba dobijenih primenom metode elektrohemijske anodizacije i njihova primena u bio dekontaminaciji.Taking into account the importance of development of the advanced nanomaterials for the environmental protection, in this article the application of TiO2 based nanomaterials and nanostructures in the fields of renewable energy, chemical and bio decontamination has been presented. The role of TiO2 in formation of composite hybrid structures for solar energy harvesting has been explained, as well as the use photocatalytic degradation of pollutants. properties of TiO2 nanotubes obtained by decontamination

Automatic microstructure analysis of sintered materials

U ovom radu je prezentovana nova metoda za automatsku mikrostrukturnu analizu materijala. Metoda je bazirana na prepoznavanju kontura i dekompoziciji digitalne slike na osnovu fotometrijskih zakona, kao i na primeni log hiperbolične distribucije. Ova metoda je uspešno primenjena za mikrostrukturnu analizu neizotermski sinterovanog barijum-titanata.In this article the new approach to automatic microstructure analysis of the sintered materials has been presented. The method is based on contour recognition and decomposition of digital image, according to their gray scale intensity and the use of log-hyperbolic grain size distribution and it has been successfully applied on microstructure analysis of BaTiO3 sintered under non isothermal conditions

Automatic microstructure analysis of sintered materials

U ovom radu je prezentovana nova metoda za automatsku mikrostrukturnu analizu materijala. Metoda je bazirana na prepoznavanju kontura i dekompoziciji digitalne slike na osnovu fotometrijskih zakona, kao i na primeni log hiperbolične distribucije. Ova metoda je uspešno primenjena za mikrostrukturnu analizu neizotermski sinterovanog barijum-titanata.In this article the new approach to automatic microstructure analysis of the sintered materials has been presented. The method is based on contour recognition and decomposition of digital image, according to their gray scale intensity and the use of log-hyperbolic grain size distribution and it has been successfully applied on microstructure analysis of BaTiO3 sintered under non isothermal conditions

Pulsed Laser Deposition of BaTiO3 on PVDF substrate

Piezoelectric materials play an important role in development of advanced Micro-electromechanical systems (MEMS) and Nano-electro-mechanical systems (NEMS). Their applications span the aero-space industry, communications, defense systems, national security, health care, information technology and environmental monitoring. Materials used in MEMS/NEMS mustsimultaneously satisfy numerous requirements for chemical, structural, mechanical and electrical properties. Although traditionally MEMS in particular have relied on silicon, the materials used in MEMS/NEMS are becoming more heterogeneous. Taking into account that materials nanostructuring can produce unique mechanical, electrical and piezoelectric properties, in this article the investigation of pulsed laser deposition of BaTiO3 on PVDF substrate has been performed. The titanium-saphire laser operated at 800 nm with 40-fs pulse duration and 1 kHz repetition rate was focused onto a mechanically activated BaTiO3 target. Deposition on PVDF substrate was done at an oxygen partial pressure of 10-7 Torr using a laser pulse frequency of 1 kHz at room temperature. The crystal structure and the microstructure of the films were examined using an X-ray diffractometer and scanning electron microscope, while the surface morphology was observed by atomic force microscopy.It was found that pulsed laser deposition of BaTiO3 on PVDF substrate offers a new set of opportunities for development of advanced flexible piezo-films for the next generation of NEMS

Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3

Prah barijum-titanata je mehanički aktiviran u planetarnom mlinu sa kuglicama 60 i 120 minuta. Neizotermsko sinterovanje neaktiviranog i aktiviranih uzoraka proučeno je u dilatometru u temperaturskom intervalu od sobne do 1380oS sa tri različite brzine zagrevanja (10, 20 i 30oS/min). Mehanizmi ranih stadijuma sinterovanja su analizirani za sva tri tipa uzoraka i uočene su značajne razlike između neaktiviranih i mehanički aktiviranih uzoraka.Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples

The impedance analysis of sintered MgTiO3 ceramics

In the present study the effect of preparation conditions on microstructure and electrical properties of MgTiO3 ceramics was investigated. Mixture of MgO and TiO2 powders was subjected to mechanical activation for different time periods. Two types of sintering (two-step and HIP sintering) were performed on green bodies prepared by cold isostatic pressing. AC impedance spectroscopy in the low-frequency range (from 20 Hz to 1 MHz), at room and elevated temperatures, were performed in order to separate contribution of grains and grain boundaries to capacitance, resistance and conductivity of magnesium titanate ceramics. The special attention was directed to explanation of the influence of mechanical activation on electrical and morphological changes in sintered samples. The significant decrease of partial oxygen pressure in HP sintering atmosphere caused the change from insulating behavior of MgTiO3 samples after two-step sintering to semiconducting one

Characterization of mechanically activated ZnO powder

Materials based on ZnO structure have more frequently application as fillers in polymer ceramics nanocompozites. Performances of these materials depends on fillers morphology, surfaces texture and particles size. According to this, in this paper, the authors investigated the influence of mechanical activation of ZnO powder on crystal and micro structure. Commercially available ZnO powder was activated in a planetary ball mill for 2, 5, 10 and 30 minutes. Characterization of such obtained powders was performed using XRD, SEM and Raman spectroscopy. XRD patterns indicated at lowering of peak intensities along with its broadening wich is realted to partical fragmentation and amorphyzation. Micrographs show irregularly shaped particles at the beginning and with prolonged milling time, particles gained uniformed distibution, while after 30 minutes of activation agglomerates started forming. The results we got by investigation of dynamical structure by Raman spectroscopy are in correlation with the other results of structures analysis. Results presented here enable further optimization of, polymer nanocompozite based on ZnO and PVDF, making process

Fabrication and applications of multifunctional nanostructured TiO2

Nanomaterials development is a rapidly emerging field of research with enormous potential for societal and economic benefits. In agro and food industries dimension-dependent properties or phenomena of nanomaterials may be used for various functional effects such as increased bioavailability or decreased toxicity of products, better detection of pathogens, improved food packaging materials, or improved delivery of nutrients. Since these effects may derive from altered or unique characteristics of materials in the nanoscale range that are not normally observed or expected in larger-scale materials with the same chemical composition, such changes raise questions about the safety, effectiveness, performance, quality or public health impact of nanotechnology products. In this article, we have reviewed the fabrication, properties, and selected applications of nanostructured TiO2 based materials. Special attention has been paid to TiO2 nanoparticles and nanotubes fabrication perspectives and applications in agriculture. We have shown that high photocatalytic disinfection and photobiological effects of nanostructured TiO2 coupled with its low price, nontoxicity, and stable performance especially provide new approaches for solving environmental pollution and pesticide residue problems in agriculture.Paper: [https://hdl.handle.net/21.15107/rcub_dais_5121