Ceramics-Silikáty 45, (1) 9 - 14 (2001) |
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STUDY OF CRYSTALLISATION OF Al₂O₃-Fe₂O₃ GELS BY MÖSSBAUER SPECTROSCOPY
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Bača Ľuboš 1, Lipka Jozef 2, Tóth Ignác 2,
Pach Ladislav 1
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1 Department of Ceramics, Glass and Cement, Faculty of Chemical Technology,
Slovak University of Technology,
Radlinského 9, 812 37 Bratislava, Slovak Republic
2 Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology,
Slovak University of Technology,
Ilkovičova 3, 812 19 Bratislava, Slovak Republic
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Boehmite derived alumina gels seeded (5 wt.%) with α-Al₂O₃, α-Fe₂O₃ and Fe(NO₃)₃ were examined by Mössbauer
spectroscopy. Feric oxide orginated from Fe(NO₃)₃ was identified in defect alumina phases in two high disperse form as solid
solution γ-(Al, Fe)₂O₃ and substituted hematite particles (α-(Fe, Al)₂O₃ ~ 6 nm). Dispersed Fe³⁺ ions reduce temperature of
the crystallisation of α-Al₂O₃ (solution (Al, Fe₂O₃)) much more significantly than particulate seeds. Enhanced transformation
has been attributed to solution effect of dispersed Fe³⁺ ions resulting in transparent ceramics sintered below 1300 °C. |
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