Transformation of Aluminum Unstable Oxyhydroxides in Ultrafine α-Al2O3 in Presence of Various Seeds
Ceramic obtained on the base of aluminum oxide has
wide application range, because it has unique properties, for example,
wear-resistance, dielectric characteristics, and exploitation ability at
high temperatures and in corrosive atmosphere. Low temperature
synthesis of α-Al2O3 is energo-economical process and it is topical
for developing technologies of corundum ceramics fabrication. In the present work possibilities of low temperature transformation
of oxyhydroxides in α-Al2O3, during the presence of small amount of
rare–earth elements compounds (also Th, Re), have been discussed.
Aluminum unstable oxyhydroxides have been obtained by hydrolysis
of aluminium isopropoxide, nitrates, sulphate, and chloride in
alkaline environment at 80-90ºC temperatures. β-Al(OH)3 has been
received from aluminum powder by ultrasonic development. Drying
of oxyhydroxide sol has been conducted with presence of various
types seeds, which amount reaches 0,1-0,2% (mas). Neodymium,
holmium, thorium, lanthanum, cerium, gadolinium, disprosium
nitrates and rhenium carbonyls have been used as seeds and they
have been added to the sol specimens in amount of 0.1-0.2% (mas)
calculated on metals. Annealing of obtained gels is carried out at 70–
1100ºC for 2 hrs. The same specimen transforms in α-Al2O3 at
1100ºC. At this temperature in case of presence of lanthanum and
gadolinium transformation takes place by 70-85%. In case of
presence of thorium stabilization of γ-and θ-phases takes place. It is
established, that thorium causes inhibition of α-phase generation at
1100ºC, and at the time when in all other doped specimens α-phase is
generated at lower temperatures (1000-1050ºC). Synthesis of various
type compounds and simultaneous consolidation has developed in the
furnace of OXY-GON. Composite materials containing oxide and
non-oxide components close to theoretical data have been obtained in
this furnace respectively. During the work the following devices have
been used: X-ray diffractometer DRON-3M (Cu-Kα, Ni filter,
2º/min), High temperature vacuum furnace OXY-GON, electronic
scanning microscopes Nikon ECLIPSE LV 150, NMM-800TRF,
planetary mill Pulverisette 7 premium line, SHIMADZU Dynamic
Ultra Micro Hardness Tester, DUH-211S, Analysette 12 Dyna sizer.
[1] H. Hou, Y. Xie, Q. Yang, Q. Guo, C. Tan. Perapration and
characterization of γ-AlOOH nanotubes and nanorods. Nanotechnol.,
2005, 16(6), 714-721.
[2] Y. Xia, Y.Yang, P. Sun, Y. Wu, B. Mayers, A. Gates, Y.Yin, F. Kim, H.
Yan, Onedimensional nanostructures: Synthesis, characterization and
applications. Adv. Mater., 2003, 15(5), 353-357.
[3] G. L. Teoh, K. Y. Liew, W. A. K. Mahmood. Synthesis and
characterization of sol–gel alumina nanofibers. J. Sol-Gel Sci. Technol.,
2007, 44(3), 177-180.
[4] M. G. Ma, J. F. Zhu. A Facile solvothermal route to synthesis of γ-
alumina with bundle-like and flower-like morphologies. Mater. Let,
2009, 63, 881-885.
[5] Q. Yang, Y. Deng, W. Hu. Synthesis of alumina nanofibers by a
mercury-mediated method. Ceram. Intern, 2009, 35(1), 531-537.
[6] S. Cava, S.M. Tebcherani, I.A. Souza, S.A. Pianaro, C.A. Paskocimas,
E. Longo, J.A. Varela. Structural characterization of phase transition of
Al2O3 nanopowders obtained by polymeric precursor method. Materials
Chemistry and Physics, 2007, 103, 394–399.
[7] A. Odaka, T. Yamaguchi, A. T. Fujita, B. S. Taruta, K. Kitajima.
Densification of rare-earth (Lu, Gd, Nd)-doped alumina nanopowders
obtained by a sol−gel route under seeding. Powder Technology, 2009,
193(1), 26-31.
[8] Yiguang Wang, C. Suryanarayana, Linan An. Phase Transformation in
nanometer-sized χ-alumina by mechanical milling. J. Am. Cer. Soc.,
2005, 88(3), 780-783.
[9] Y. Yoshizawa, K. Hirao, S. Kanzaki. Fabrication of low cost finegrained
alumina powders by seeding for high performance sintered
bodies. Journal of the European Ceramic Society, 2013, 33(13–14),
2365-2830.
[10] R. L. Smith, G. S. Rohrer, A. J. Perrotta. The Influence of diaspore
seeding and chloride concentration on the transformation of “Diasporic”
precursors to corundum. J. Am. Cer. Soc., 2001, 84(8), 1896-1902.
[11] A. Sharma, O.P. Modi, G.K. Gupta. Combustion synthesis of
nanocrystalline Al2O3 powder using aluminium nitrate and urea as
reactants-influence of reactant composition. Advances in Applied
Science Research, 2012, 3 (6), 3819-3824.
[12] T.V. Kuchukhidxe, V.G. Gabunia, Z.V. Phachulia, N.T. Jalagonia, R.V.
Chedia. Some Issues of Ultrafine Alfa-alumina Powders Fabricated by
Low Temperature Synthesis. 2014, 8, 303-312, ISSN 1314-7269,
http://www.scientific-publications.net.
[13] T.V. Kuchukhidze, N. T. Jalagonia, V. G. Gabunia, T. N. Archuadze, Q.
G. Sarajishvili, R.V.Chedia. Influence of Some Metal Ions on Low
Temperature Transformation of Alumina Metastable Oxides in
α−Al2O3. 3th International Conference « Nanotechnologies» NANO-
2014, 20-24 0ctomber, 2014, Tbilisi, Georgia.
[1] H. Hou, Y. Xie, Q. Yang, Q. Guo, C. Tan. Perapration and
characterization of γ-AlOOH nanotubes and nanorods. Nanotechnol.,
2005, 16(6), 714-721.
[2] Y. Xia, Y.Yang, P. Sun, Y. Wu, B. Mayers, A. Gates, Y.Yin, F. Kim, H.
Yan, Onedimensional nanostructures: Synthesis, characterization and
applications. Adv. Mater., 2003, 15(5), 353-357.
[3] G. L. Teoh, K. Y. Liew, W. A. K. Mahmood. Synthesis and
characterization of sol–gel alumina nanofibers. J. Sol-Gel Sci. Technol.,
2007, 44(3), 177-180.
[4] M. G. Ma, J. F. Zhu. A Facile solvothermal route to synthesis of γ-
alumina with bundle-like and flower-like morphologies. Mater. Let,
2009, 63, 881-885.
[5] Q. Yang, Y. Deng, W. Hu. Synthesis of alumina nanofibers by a
mercury-mediated method. Ceram. Intern, 2009, 35(1), 531-537.
[6] S. Cava, S.M. Tebcherani, I.A. Souza, S.A. Pianaro, C.A. Paskocimas,
E. Longo, J.A. Varela. Structural characterization of phase transition of
Al2O3 nanopowders obtained by polymeric precursor method. Materials
Chemistry and Physics, 2007, 103, 394–399.
[7] A. Odaka, T. Yamaguchi, A. T. Fujita, B. S. Taruta, K. Kitajima.
Densification of rare-earth (Lu, Gd, Nd)-doped alumina nanopowders
obtained by a sol−gel route under seeding. Powder Technology, 2009,
193(1), 26-31.
[8] Yiguang Wang, C. Suryanarayana, Linan An. Phase Transformation in
nanometer-sized χ-alumina by mechanical milling. J. Am. Cer. Soc.,
2005, 88(3), 780-783.
[9] Y. Yoshizawa, K. Hirao, S. Kanzaki. Fabrication of low cost finegrained
alumina powders by seeding for high performance sintered
bodies. Journal of the European Ceramic Society, 2013, 33(13–14),
2365-2830.
[10] R. L. Smith, G. S. Rohrer, A. J. Perrotta. The Influence of diaspore
seeding and chloride concentration on the transformation of “Diasporic”
precursors to corundum. J. Am. Cer. Soc., 2001, 84(8), 1896-1902.
[11] A. Sharma, O.P. Modi, G.K. Gupta. Combustion synthesis of
nanocrystalline Al2O3 powder using aluminium nitrate and urea as
reactants-influence of reactant composition. Advances in Applied
Science Research, 2012, 3 (6), 3819-3824.
[12] T.V. Kuchukhidxe, V.G. Gabunia, Z.V. Phachulia, N.T. Jalagonia, R.V.
Chedia. Some Issues of Ultrafine Alfa-alumina Powders Fabricated by
Low Temperature Synthesis. 2014, 8, 303-312, ISSN 1314-7269,
http://www.scientific-publications.net.
[13] T.V. Kuchukhidze, N. T. Jalagonia, V. G. Gabunia, T. N. Archuadze, Q.
G. Sarajishvili, R.V.Chedia. Influence of Some Metal Ions on Low
Temperature Transformation of Alumina Metastable Oxides in
α−Al2O3. 3th International Conference « Nanotechnologies» NANO-
2014, 20-24 0ctomber, 2014, Tbilisi, Georgia.
@article{"International Journal of Chemical, Materials and Biomolecular Sciences:71128", author = "T. Kuchukhidze and N. Jalagonia and Z. Phachulia and R. Chedia", title = "Transformation of Aluminum Unstable Oxyhydroxides in Ultrafine α-Al2O3 in Presence of Various Seeds", abstract = "Ceramic obtained on the base of aluminum oxide has
wide application range, because it has unique properties, for example,
wear-resistance, dielectric characteristics, and exploitation ability at
high temperatures and in corrosive atmosphere. Low temperature
synthesis of α-Al2O3 is energo-economical process and it is topical
for developing technologies of corundum ceramics fabrication. In the present work possibilities of low temperature transformation
of oxyhydroxides in α-Al2O3, during the presence of small amount of
rare–earth elements compounds (also Th, Re), have been discussed.
Aluminum unstable oxyhydroxides have been obtained by hydrolysis
of aluminium isopropoxide, nitrates, sulphate, and chloride in
alkaline environment at 80-90ºC temperatures. β-Al(OH)3 has been
received from aluminum powder by ultrasonic development. Drying
of oxyhydroxide sol has been conducted with presence of various
types seeds, which amount reaches 0,1-0,2% (mas). Neodymium,
holmium, thorium, lanthanum, cerium, gadolinium, disprosium
nitrates and rhenium carbonyls have been used as seeds and they
have been added to the sol specimens in amount of 0.1-0.2% (mas)
calculated on metals. Annealing of obtained gels is carried out at 70–
1100ºC for 2 hrs. The same specimen transforms in α-Al2O3 at
1100ºC. At this temperature in case of presence of lanthanum and
gadolinium transformation takes place by 70-85%. In case of
presence of thorium stabilization of γ-and θ-phases takes place. It is
established, that thorium causes inhibition of α-phase generation at
1100ºC, and at the time when in all other doped specimens α-phase is
generated at lower temperatures (1000-1050ºC). Synthesis of various
type compounds and simultaneous consolidation has developed in the
furnace of OXY-GON. Composite materials containing oxide and
non-oxide components close to theoretical data have been obtained in
this furnace respectively. During the work the following devices have
been used: X-ray diffractometer DRON-3M (Cu-Kα, Ni filter,
2º/min), High temperature vacuum furnace OXY-GON, electronic
scanning microscopes Nikon ECLIPSE LV 150, NMM-800TRF,
planetary mill Pulverisette 7 premium line, SHIMADZU Dynamic
Ultra Micro Hardness Tester, DUH-211S, Analysette 12 Dyna sizer.", keywords = "α-Alumina, combustion, consolidation, phase
transformation, seeding.", volume = "9", number = "7", pages = "907-5", }