TY  - JOUR
AU  - Đorđević, Nataša
AU  - Martinović, S.
AU  - Vlahović, M.
AU  - Jovanić, P.
AU  - Vidojković, Velislav M.
AU  - Boljanac, Tamara
PY  - 2009
UR  - https://ritnms.itnms.ac.rs/handle/123456789/158
AB  - Sinterovanjem sistema 2MgO·2Al2O3·5SiO2, dobija se kordijerit, koji zbog svojih svojstava predstavlja izuzetno atraktivan keramički materijal. U cilju ispitivanja mogućnosti sniženja temperature formiranja kordijerita tokom procesa sinterovanja, izvršena su preliminarna ispitivanja mehanohemijske aktivacije stehiometrijske smeše polaznih komponenti. Efekti mehanohemijske aktivacije su praćeni termogravimetrijskom i diferencijalnom termijskom analizom. Specifična površina mehanički aktivirane smeše prahova je određivana BET i Coulter metodom. Kinetika povećanja specifične površine je analizirana tzv. Boltzmann-ovim modelom. Utvrđeno je da se sa povećanjem vremena aktivacije temperature na kojima se uočavaju fazne promene pomeraju ka nižim vrednostima. FFT IR analiza mehanohemijski aktiviranog praha nakon 24 meseci je pokazala da nije došlo do bitnih promena tokom 'starenja' materijala. Na osnovu dobijenih rezultata može se zaključiti da je mehanohemijska aktivacija imala uticaja na tretiranu praškastu smešu, pa se očekuje da se ovaj uticaj odrazi i na sniženje temperature formiranja kordijerita tokom procesa sinterovanja.
AB  - During sintering of the 2MgO-2Al2O3-5SiO2 system, cordierite, an attractive ceramic material because of its properties, is obtained. Effects of mechanochemical activation of stoichiometric mixtures, performed to investigate possibilities of lowering cordierite formation temperature during sintering, were monitored by thermogravimetric and differential thermal analyses. Specific surface areas of the mechanically activated powder mixtures were determined by the BET method. Kinetics of the specific surface area increase was analyzed using the Boltzmann model. It was confirmed that with activation time increase, temperatures of phase transformations were shifted to lower values and, according to FTIR analysis no significant changes occurred during material aging. According to the obtained results, it may be concluded that since mechanochemical activation has an influence on the treated powder mixture, lowering of the cordierite formation temperature during the sintering process is expected.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Kinetics of specific surface area change using the Boltzmann model
EP  - 274
IS  - 3
SP  - 267
VL  - 41
DO  - 10.2298/SOS0903267D
UR  - conv_579
ER  - 

@article{
author = "Đorđević, Nataša and Martinović, S. and Vlahović, M. and Jovanić, P. and Vidojković, Velislav M. and Boljanac, Tamara",
year = "2009",
abstract = "Sinterovanjem sistema 2MgO·2Al2O3·5SiO2, dobija se kordijerit, koji zbog svojih svojstava predstavlja izuzetno atraktivan keramički materijal. U cilju ispitivanja mogućnosti sniženja temperature formiranja kordijerita tokom procesa sinterovanja, izvršena su preliminarna ispitivanja mehanohemijske aktivacije stehiometrijske smeše polaznih komponenti. Efekti mehanohemijske aktivacije su praćeni termogravimetrijskom i diferencijalnom termijskom analizom. Specifična površina mehanički aktivirane smeše prahova je određivana BET i Coulter metodom. Kinetika povećanja specifične površine je analizirana tzv. Boltzmann-ovim modelom. Utvrđeno je da se sa povećanjem vremena aktivacije temperature na kojima se uočavaju fazne promene pomeraju ka nižim vrednostima. FFT IR analiza mehanohemijski aktiviranog praha nakon 24 meseci je pokazala da nije došlo do bitnih promena tokom 'starenja' materijala. Na osnovu dobijenih rezultata može se zaključiti da je mehanohemijska aktivacija imala uticaja na tretiranu praškastu smešu, pa se očekuje da se ovaj uticaj odrazi i na sniženje temperature formiranja kordijerita tokom procesa sinterovanja., During sintering of the 2MgO-2Al2O3-5SiO2 system, cordierite, an attractive ceramic material because of its properties, is obtained. Effects of mechanochemical activation of stoichiometric mixtures, performed to investigate possibilities of lowering cordierite formation temperature during sintering, were monitored by thermogravimetric and differential thermal analyses. Specific surface areas of the mechanically activated powder mixtures were determined by the BET method. Kinetics of the specific surface area increase was analyzed using the Boltzmann model. It was confirmed that with activation time increase, temperatures of phase transformations were shifted to lower values and, according to FTIR analysis no significant changes occurred during material aging. According to the obtained results, it may be concluded that since mechanochemical activation has an influence on the treated powder mixture, lowering of the cordierite formation temperature during the sintering process is expected.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Kinetics of specific surface area change using the Boltzmann model",
pages = "274-267",
number = "3",
volume = "41",
doi = "10.2298/SOS0903267D",
url = "conv_579"
}

Đorđević, N., Martinović, S., Vlahović, M., Jovanić, P., Vidojković, V. M.,& Boljanac, T.. (2009). Kinetics of specific surface area change using the Boltzmann model. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 41(3), 267-274.
https://doi.org/10.2298/SOS0903267D
conv_579

Đorđević N, Martinović S, Vlahović M, Jovanić P, Vidojković VM, Boljanac T. Kinetics of specific surface area change using the Boltzmann model. in Science of Sintering. 2009;41(3):267-274.
doi:10.2298/SOS0903267D
conv_579 .

Đorđević, Nataša, Martinović, S., Vlahović, M., Jovanić, P., Vidojković, Velislav M., Boljanac, Tamara, "Kinetics of specific surface area change using the Boltzmann model" in Science of Sintering, 41, no. 3 (2009):267-274,
https://doi.org/10.2298/SOS0903267D .,
conv_579 .

TY  - JOUR
AU  - Đorđević, Nataša
AU  - Jovanić, P.B.
PY  - 2008
UR  - https://ritnms.itnms.ac.rs/handle/123456789/137
AB  - Cilj ovog istraživanja je bio da ispita moguće korelacije funkcionalnih svojstava kordijeritne keramike u funkciji od pripreme polazne smeše. Trokomponentni sistem sastava MgO+Al2O3+SiO2 u odnosu 2:2:5 je pripremljen sa dodatkom 10% Bi2O3. Smeša je mehanohemijski aktivirana 5 i 240 minuta u mlinu sa keramičkim kuglama i sinterovana u temperaturnom opsegu od 1173-1573K. Strukturne transformacije su praćene rendgenostrukturnom analizom. Kvantitativne promene funkcionalnih svojstava uzoraka praćene su merenjem kapacitivnosti Cc, električne otpornosti Rρ, i tangensa ugla dielektričnih gubitaka. Rezultati su dokazali korelaciju između mehanohemijske aktivacije i svojstava kordijeritne keramike.
AB  - The goal of the presented research was to find a possible correlation of the process parameters and functional properties of cordierite based ceramic materials. A three component oxide mixture was prepared containing MgO+Al2O3+SiO2 in the 2:2:5 ratio with the addition of 10% Bi2O3. Mixtures were mechanochemically activated 5 and 240 minutes in a mill with ceramic balls, and sintered at temperatures from 1173-1573K. Structural transformations were determined by the XRD method. Quantitative measures of the functional sample properties, capacity Cc and electrical resistance Rρ as well as tangens of dielectric loss angle tg α were used. The results obtained proved that there is a correlation between mechanochemical activation and properties of cordierite ceramics.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Influence of mechanical activation on elelctrical properties of cordierite ceramics
EP  - 53
IS  - 1
SP  - 47
VL  - 40
DO  - 10.2298/SOS0801047D
UR  - conv_1095
ER  - 

@article{
author = "Đorđević, Nataša and Jovanić, P.B.",
year = "2008",
abstract = "Cilj ovog istraživanja je bio da ispita moguće korelacije funkcionalnih svojstava kordijeritne keramike u funkciji od pripreme polazne smeše. Trokomponentni sistem sastava MgO+Al2O3+SiO2 u odnosu 2:2:5 je pripremljen sa dodatkom 10% Bi2O3. Smeša je mehanohemijski aktivirana 5 i 240 minuta u mlinu sa keramičkim kuglama i sinterovana u temperaturnom opsegu od 1173-1573K. Strukturne transformacije su praćene rendgenostrukturnom analizom. Kvantitativne promene funkcionalnih svojstava uzoraka praćene su merenjem kapacitivnosti Cc, električne otpornosti Rρ, i tangensa ugla dielektričnih gubitaka. Rezultati su dokazali korelaciju između mehanohemijske aktivacije i svojstava kordijeritne keramike., The goal of the presented research was to find a possible correlation of the process parameters and functional properties of cordierite based ceramic materials. A three component oxide mixture was prepared containing MgO+Al2O3+SiO2 in the 2:2:5 ratio with the addition of 10% Bi2O3. Mixtures were mechanochemically activated 5 and 240 minutes in a mill with ceramic balls, and sintered at temperatures from 1173-1573K. Structural transformations were determined by the XRD method. Quantitative measures of the functional sample properties, capacity Cc and electrical resistance Rρ as well as tangens of dielectric loss angle tg α were used. The results obtained proved that there is a correlation between mechanochemical activation and properties of cordierite ceramics.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Influence of mechanical activation on elelctrical properties of cordierite ceramics",
pages = "53-47",
number = "1",
volume = "40",
doi = "10.2298/SOS0801047D",
url = "conv_1095"
}

Đorđević, N.,& Jovanić, P.B.. (2008). Influence of mechanical activation on elelctrical properties of cordierite ceramics. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 40(1), 47-53.
https://doi.org/10.2298/SOS0801047D
conv_1095

Đorđević N, Jovanić P. Influence of mechanical activation on elelctrical properties of cordierite ceramics. in Science of Sintering. 2008;40(1):47-53.
doi:10.2298/SOS0801047D
conv_1095 .

Đorđević, Nataša, Jovanić, P.B., "Influence of mechanical activation on elelctrical properties of cordierite ceramics" in Science of Sintering, 40, no. 1 (2008):47-53,
https://doi.org/10.2298/SOS0801047D .,
conv_1095 .