Ceramics-Silikáty 47 (4) 149-154 (2003)

EFFECT OF ORGANIC ADDITIVES ON CRYSTALLIZATION OF BOEHMITE GELS

Z. Holková, L. Pach, J. Majling, J. Kákoš, M. Kadlečíková

Monolithic planar boehmite gels of thickness of ~0.15 mm unseeded, seeded by Fe(NO₃)₃ and doped (3 wt.%) with organics (PVA, PEG and EG) were examined by photoluminescence spectroscopy, in-situ optical transmittance and SEM. Polymeric organic additives although burned up at low temperatures (550°C), leave microstructure traces, having significant effect on high temperature processes, crystallization and sintering. Actually, polymeric additives (PVA or PEG) cancel a profound positive high effect of Fe(NO₃)₃ to a-Al₂O₃ nucleation.

Keywords: Boehmite, Gel, Seeding, Crystallization, Organic Additives, PVA, EG.