Effect of microstructure on mechanical properties of Al2O3-Y3AL5O12 composite ceramics

U okviru ove doktorske disertacije proučene su dve metode dobijanja Al2O3-Y3Al5O12 kompozita i ispitan je uticaj mikrostrukture na osobine dobijene kompozitne keramike. Ispitivanja su obuhvatila metode sinteze Itrijum (Yttrium) Aluminijum Garneta (YAG) hemijske formule Y3Al5O12 kao i njegove inkorporacije u alumina (Al2O3) matricu u cilju dobijanja kako poroznog tako i gustog kompozita sa poboljšanim osobinama u odnosu na čistu aluminu...Within this doctoral dissertation, two methods of obtaining Al2O3-Y3Al5O12 composite were studied as well as the effects of the microstructure on the properties of the obtained composite ceramics. The study included the methods of synthesis of Yttrium Aluminium Garnet (YAG) with chemical formula Y3Al5O12 as well as its incorporation into alumina (Al2O3) matrix in order to obtain both porous and dense composites with improved properties relatively to pure alumina..

Synthesis of crystaline silicon oxynitride composites

Silicon oxynitride / silicon nitride (Si2N2O/Si3N4) ceramics have been prepared from Si3N4 powder and amorphous silica (SiO2) by hot pressing at different temperature. It was found that material sintered at lower temperature exhibit fine composite structure composed of equiaxed α-Si3N4 grains and Si2N2O crystals. At higher temperature the growing of Si2N2O particles as well as phase transformation from α-Si3N4 to β-Si3N4 phase take place.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Supporting information for the article: Lukić, M.J., Kuzmanović, M., Sezen, M., Bakan, F., Egelja, A., Veselinović, L., 2018. Inert atmosphere processing of hydroxyapatite in the presence of lithium iron phosphate. Journal of the European Ceramic Society 38, 2120–2133. https://doi.org/10.1016/j.jeurceramsoc.2017.12.023

Supporting information for the article: [https://doi.org/10.1016/j.jeurceramsoc.2017.12.023].Related to the peer-reviewed manuscript: [https://hdl.handle.net/21.15107/rcub_dais_4924]Related to the published version: [https://hdl.handle.net/21.15107/rcub_dais_3357

Application of FeAl-LDH@SiO2 for Phosphate Removal from Water

In present study FEAL-LDH@SIO2 were Used for removing phosphate from aqueous solutions. FeAl-LDH with molar ratio Fe/Al = 3/1 was synthesized by co- precipitation from aqueous solutions in the present of SIO2 PARTICLES. Silica obtained from rice husks were used as a substrate for the deposition of LDH particles. The prepared material was characterized by scanning electron microscope (FE-SEM), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET method) and Fourier transform infrared spectroscopy (FTIR). XRD analysis showed that Fe-Al had formed LDH structure. SEM analysis revealed deposition of LDH particles on SIO2 SUBSTRATE. The adsorption characteristics for phosphate uptake of the obtained material were performed. Adsorption experiments were carried out as a function of LDHs dosage with three different mass ratios of LDH/silica = 1/1, 2/1, and 3/1 and different phosphate concentration AT INITIAL PH 4. Phosphate concentrations were determined using spectrophotometer. The results showed that the maximum sorption capacities of phosphates calculated based on Langmuir equation was 52.68 mg g-1.The book of abstract available at: [http://conf.univerzitetpim.com/wp-content/uploads/2022/06/Book-of-Abstracts_2022-1.pdf

Mechanical Properties of Composite Material Reinforced With Silica Particles Obtained from Biomass Modified With Double-Layered Hydroxides

Silica particles were produced form rice husk and used as reinforcement in the polymer matrix. The obtained silica particles' surfaces were modified with layered double hydroxides, which enabled better reinforcement in the PMMA matrix. Coprecipitation was used to synthetize Fe Al layered double hydroxides (LDH) with a Fe:Al cation content of 3:1 and an FeAl-LDH: silica ratio of 1:1. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with EDS were used to characterize the synthesized particles. The prepared particle amounts in the PMMA matrix were 1, 3, and 5 wt. %. The purpose of this study was to see if the obtained SiO2 particles, as well as their modification with FeAl-LDH, had any effect on the mechanical properties of polymer composite materials. The mechanical characterization of obtained composites was done using Vickers microindentation tests and impact testing. The Vickers micro-hardness test showed that the addition of reinforcement increases the hardness of the composite. When compared to the matrix, the toughness of the composite material with a higher content of particles (5 wt. %) in the energy absorbed in this impact test was three times higher.The book of abstract available at: [http://conf.univerzitetpim.com/wp-content/uploads/2022/06/Book-of-Abstracts_2022-1.pdf

The influence of temperature on microstructure of mullite sintered at high pressure

The effect of sintering temperature on microstructure and density of the sintered mullite samples during the high pressure sintering process was investigated. High pressure sintering is one of the effective methods for producing fully dense bulk ceramics products enhancing densification and limiting grain growth. Synthesized mullite precursor powder was calcinated at 1200 °C for 4 h in order to obtain crystalline mullite powder that was confirmed by XRPD analysis. To determine the optimum sintering temperature for obtaining fully dense mullite samples crystalline mullite powder was compacted at 4.0 GPa in the temperature range 1100-1500 °C with step of 100 °C for 60 s. The measured densities of sintered samples rise with increasing the sintering temperature due to recrystallization of mullite particles. The particles of the starting powder are agglomerated while the microstructure of sintered samples reveals needle-like grains. The needles become elongated with increasing the temperature of sintering process and reach the grain length about 5 μm at 1400 and 1500 °C whereas the grains at 1500 °C are wider.III Conference of The Serbian Society for Ceramic Materials, 3CSCS-2015, June 15-17, 2015, Belgrade, Serbi

Preparation of biomorphic SiC ceramics

This paper deals with a new method for producing non-oxide ceramic using wood as a template. SiC with a woodlike microstructure has been prepared by carbothermal reduction reactions of Tilia wood/TEOS composite at 1873K. The porous carbon preform was infiltrated with TEOS (Si(OC(2)H(5))(4)), as a source of silica, without pressure at 298K. The morphology of resulting porous SiC ceramics, as well as the conversion mechanism of wood to SiC ceramics, have been investigated by scanning electron microscopy (SEM/EDS) and X-ray diffraction analysis (XRD). Obtained SiC ceramics consists of beta-SiC with traces of alpha-SiC

Characterization of clay from Kolubara mining basin, Serbia

VIII Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 23-25, 2019; Belgrad

Y3Al5O12:Re3+ (Re=Ce, Eu, and Sm) Nanocrystalline Powders Prepared by Modified Glycine Combustion Method

Yttrium aluminum garnet doped with rare earth ions (Ce3+, Eu3+ and Sm3+) was prepared by modified glycine method. Ce3+ as a dopant was used in four different concentrations (Y3-xCexAl5O12; x(%) = 1, 2, 3, 5), while doping concentration of Eu3+ and Sm3+ was Y3-xEuxAl5O12; x(%) = 3 and Y3-xSmxAl5O12; x(%) = 1, respectively. Phase composition of powders was investigated using XRD technique and expected target phase was confirmed. Photoluminescent characterization included measurements of excitation and emission spectra, as well as determination of emission decays. Y3-xCexAl5O12 shows intense broad-band emission, with maximum in green spectral region, at about 524 nm under ultraviolet or blue excitation. The origin of the luminescence is the 5d(1)- GT 4f(1) transition which is both parity and spin allowed. Ultraviolet and blue excitations of Eu3+ and Sm3+ doped Y3Al5O12 produce intense orange and red emissions. These emissions are phosphorescent in character and come from spin forbidden f-f electron transitions in Eu3+ and Sm3+ ions. For the case of Eu3+ doping emission comes mainly from D-5(0)- GT F-7(1) transitions with Stark components peaking at 590 nm and 590.75 nm, and with emission decay of 4.15 ms. In the case of Sm3+ doping, the emission spectrum, shows (4)G(5/2)- GT H-6(5/2), (4)G(5/2)- GT H-6(7/2), and (4)G(5/2)- GT H-6(9/2) transitions, with the most intense stark components positioned at 567.5 nm, 617 nm, and 650 nm, respectively and for transition centered at 617 nm, emission decay is 3.12 ms