Crystallization of hafnia and zirconia during the pyrolysis of acetate gels

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1997.0342· OSTI ID:554341

Yashima, M ^[1]; Kato, T; Kakihana, M; Gulgun, M A ^[2]; Matsuo, Y ^[3]; Yoshimura, M ^[4]

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1. Department of Materials Science and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama-shi, 226-8502 (Japan)
2. Materials and Structures Laboratory and Center for Materials Design, Tokyo Institute of Technology, 4259Nagatsuta, Midori-ku, Yokohama-shi, 226-8503 (Japan)
3. Department of Inorganic Materials, Faculty of Engineering, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)
4. Center for Materials Design, Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama-shi, 226-8503 (Japan)

Hafnia and zirconia gels were prepared by drying hafnyl or zirconyl acetate solutions. Hafnia and zirconia gels contain both hydroxyl group and bidentate acetates which are directly bonded to the metal ions. Thermal decomposition and crystallization behavior of the gels were investigated through XRD, FT-IR and TEM. Hafnium-containing gels crystallized directly into stable monoclinic hafnia around 500{endash}540{degree}C, while zirconium containing gels first formed metastable tetragonal zirconia around 450{degree}C. The dissimilar crystallization behavior of the gels into metastable, tetragonal zirconia or into stable, monoclinic hafnia can be explained through the difference in free-energy changes of the tetragonal-to-monoclinic phase transformation. {copyright} {ital 1997 Materials Research Society.}

• OSTI ID: 554341
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 10 Vol. 12; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTALLIZATION
DECOMPOSITION
HAFNIUM OXIDES
ZIRCONIUM OXIDES