Temperature dependence of amorphization for zirconolite and perovskite irradiated with 1 MeV krypton ions

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:382926

White, T J ^[1]; Ewing, R C; Wang, L M ^[2]; Forrester, J S; Montross, C ^[3]

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1. Univ. of South Australia, The Levels, South Australia (Australia). Ian Wark Research Inst.
2. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences
3. Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Mining and Metallurgical Engineering

A transmission electron microscope investigation was made of zirconolites and perovskites irradiated to amorphization with 1 MeV krypton ions using the HVEM-Tandem Facility at Argonne National Laboratory. Three specimens were examined -- a prototype zirconolite CaZrTi{sub 2}O{sub 7}, a gadolinium doped zirconolite Ca{sub 0.75}Gd{sub 0.50}Zr{sub 0.75}Ti{sub 2}O{sub 7} and a uranium doped zirconolite Ca{sub 0.75}U{sub 0.50}Zr{sub 0.75}Ti{sub 2}O{sub 7}. The critical amorphization dose D{sub c} was determined at several temperatures between 20K to 675K. D{sub c} was inversely proportional with temperature. For example, pure zirconolite requiring 10x the dose for amorphization at 475K compared with gadolinium zirconolite. Using an Arrhenius plot, the activation energy E{sub a} for annealing in these compounds was found to be 0.129 eV and 0.067 eV respectively. The greater ease of amorphization for the gadolinium sample is probably a reflection of this element`s large cross section for interaction with heavy ions. Uranium zirconolite was very susceptible to damage and amorphized under 4 keV argon ions during the preparation of microscope specimens. In each sample, zirconolite coexisted with minor perovskite, reduced rutile (Magneli phases) and zirconia. These phases were more resistant to ion irradiation than zirconolite. Even for high gadolinium loadings, perovskite (Ca{sub 0.8}Gd{sub 0.2}TiO{sub 3}) was 3--4 times more stable to ion irradiation than the surrounding zirconolite crystals.

• OSTI ID: 382926
• Report Number(s): CONF-941075--; ISBN 1-55899-253-7
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
AMORPHOUS STATE
DOPED MATERIALS
PEROVSKITE
PHASE TRANSFORMATIONS
PHYSICAL RADIATION EFFECTS
RADIOACTIVE WASTE DISPOSAL
SYNROC PROCESS
SYNTHETIC ROCKS
WASTE FORMS
ZIRCONOLITE