ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 45, (1) 9 - 14 (2001)


STUDY OF CRYSTALLISATION OF Al₂O₃-Fe₂O₃ GELS BY MÖSSBAUER SPECTROSCOPY
 
Bača Ľuboš 1, Lipka Jozef 2, Tóth Ignác 2, Pach Ladislav 1
 
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

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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