Nanostructure evolution during chemical processing of gels: A high-resolution electron microscope study. 1. Rare earth oxide and hydroxycarbonate colloids

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(90)90227-O· OSTI ID:6291013

Kang, Z C; Eyring, L ^[1]

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1. Arizona State Univ., Tempe (USA)

The steps in the evolution of colloidal gels during drying, aging, and crystallization into ceramic oxides are followed by high-resolution electron microscopy. Two systems are discussed in this paper. Colloidal ceric hydroxide gels in two morphologies were studied. In one, spherical gel particles with only short-range order were observed to dehydrate to polycrystalline CeO{sub 2} with large grain size. In the other a polycrystalline precipitate of CeO{sub 2} was observed to increase its order without altering its grain size. Colloidal terbium hydroxycarbonate is also observed to have short-range order even in the earliest stages. In contrast to the cerium oxide these disordered materials are observed to crystallize and decompose in dynamic stages (even revealing reversibilities) through the intermediate dioxymonocarbonate to the oxide as carbon dioxide and water are removed.

• OSTI ID: 6291013
• Journal Information: Journal of Solid State Chemistry; (USA), Vol. 88:1; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
CHEMICAL PREPARATION
ELECTRON MICROSCOPY
COLLOIDS
EXPERIMENTAL DATA
GELS
MEASURING METHODS
RARE EARTH COMPOUNDS
CERIUM COMPOUNDS
CHALCOGENIDES
DATA
DISPERSIONS
INFORMATION
MICROSCOPY
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SYNTHESIS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies