Mechanical activation of the gamma to alpha transition in Al2O3
Abstract
The phase transformation of mechanically treated gamma-Al2O3 for grinding times up to 600 min was studied. The grinding was performed under a centrifugal force, through impact and friction, at a speed of 1000 min(-1). After mechanical activation up to 120 min, the powder was heated in the temperature range 800-1100 degrees C, from 1 to 4 hours. The phase composition of samples that were only milled and of those that were milled and heated was followed using an X-ray method. The change in the specific surface area of the starting powder subjected to grinding was measured. In the case of powders mechanically treated up to 120 min and not heated afterwards, the gamma -- GT delta-Al2O3 transition was observed with the appearance of small amounts of the alpha phase. After 600 min of grinding the previously formed delta phase was transformed into theta-Al2O3. In the case of both mechanically treated and unground powders which were heated afterwards, the phase transition to the alpha phase co...uld be described by the scheme gamma -- GT delta -- GT theta -- GT alpha-Al2O3. It developed at lower temperatures in the case of powders ground for a longer time. The kinetics of alpha-phase formation was also dependent on the time of previous mechanical treatment.
Keywords:
mechanical activation / phase transition / aluminium oxide phase transformation / grindingSource:
Powder Technology, 1997, 91, 1, 49-54
DOI: 10.1016/S0032-5910(96)03244-5
ISSN: 0032-5910
WoS: A1997XA52500007
Scopus: 2-s2.0-0031127886
Collections
Institution/Community
VinčaTY - JOUR AU - Kostić, Emilija M. AU - Kiss, Sandor J. AU - Bošković, Snežana B. AU - Zec, Slavica PY - 1997 UR - https://vinar.vin.bg.ac.rs/handle/123456789/2067 AB - The phase transformation of mechanically treated gamma-Al2O3 for grinding times up to 600 min was studied. The grinding was performed under a centrifugal force, through impact and friction, at a speed of 1000 min(-1). After mechanical activation up to 120 min, the powder was heated in the temperature range 800-1100 degrees C, from 1 to 4 hours. The phase composition of samples that were only milled and of those that were milled and heated was followed using an X-ray method. The change in the specific surface area of the starting powder subjected to grinding was measured. In the case of powders mechanically treated up to 120 min and not heated afterwards, the gamma -- GT delta-Al2O3 transition was observed with the appearance of small amounts of the alpha phase. After 600 min of grinding the previously formed delta phase was transformed into theta-Al2O3. In the case of both mechanically treated and unground powders which were heated afterwards, the phase transition to the alpha phase could be described by the scheme gamma -- GT delta -- GT theta -- GT alpha-Al2O3. It developed at lower temperatures in the case of powders ground for a longer time. The kinetics of alpha-phase formation was also dependent on the time of previous mechanical treatment. T2 - Powder Technology T1 - Mechanical activation of the gamma to alpha transition in Al2O3 VL - 91 IS - 1 SP - 49 EP - 54 DO - 10.1016/S0032-5910(96)03244-5 ER -
@article{ author = "Kostić, Emilija M. and Kiss, Sandor J. and Bošković, Snežana B. and Zec, Slavica", year = "1997", abstract = "The phase transformation of mechanically treated gamma-Al2O3 for grinding times up to 600 min was studied. The grinding was performed under a centrifugal force, through impact and friction, at a speed of 1000 min(-1). After mechanical activation up to 120 min, the powder was heated in the temperature range 800-1100 degrees C, from 1 to 4 hours. The phase composition of samples that were only milled and of those that were milled and heated was followed using an X-ray method. The change in the specific surface area of the starting powder subjected to grinding was measured. In the case of powders mechanically treated up to 120 min and not heated afterwards, the gamma -- GT delta-Al2O3 transition was observed with the appearance of small amounts of the alpha phase. After 600 min of grinding the previously formed delta phase was transformed into theta-Al2O3. In the case of both mechanically treated and unground powders which were heated afterwards, the phase transition to the alpha phase could be described by the scheme gamma -- GT delta -- GT theta -- GT alpha-Al2O3. It developed at lower temperatures in the case of powders ground for a longer time. The kinetics of alpha-phase formation was also dependent on the time of previous mechanical treatment.", journal = "Powder Technology", title = "Mechanical activation of the gamma to alpha transition in Al2O3", volume = "91", number = "1", pages = "49-54", doi = "10.1016/S0032-5910(96)03244-5" }
Kostić, E. M., Kiss, S. J., Bošković, S. B.,& Zec, S.. (1997). Mechanical activation of the gamma to alpha transition in Al2O3. in Powder Technology, 91(1), 49-54. https://doi.org/10.1016/S0032-5910(96)03244-5
Kostić EM, Kiss SJ, Bošković SB, Zec S. Mechanical activation of the gamma to alpha transition in Al2O3. in Powder Technology. 1997;91(1):49-54. doi:10.1016/S0032-5910(96)03244-5 .
Kostić, Emilija M., Kiss, Sandor J., Bošković, Snežana B., Zec, Slavica, "Mechanical activation of the gamma to alpha transition in Al2O3" in Powder Technology, 91, no. 1 (1997):49-54, https://doi.org/10.1016/S0032-5910(96)03244-5 . .