Characteristics of Radiation-induced Defects in Fluorite Structure Oxides Formed by Electron Irradiation
- PDF / 2,630,777 Bytes
- 14 Pages / 538 x 718 pts Page_size
- 27 Downloads / 218 Views
1043-T12-02
Characteristics of Radiation-induced Defects in Fluorite Structure Oxides Formed by Electron Irradiation
K. Yasuda, K. Yasunaga, S. Matsumura
Department Materials of Applied Quantum Physics and Nuclear Engineering, © 2008 Research Society Kyushu University, JAPAN
T. Sonoda Central Research Institute of Electric Power Industry, JAPAN
This study was supported by the Budget for Nuclear Research of MEXT, based on the screening and counseling by the Atomic Energy Commission, as well as Grant-in-Aid for Scientific Research from JSPS. MRS 2007 Fall Meeting, Symposium T, Boston, USA, Nov.25-30, 2007
Oxides with fluorite Structure Excellent radiation resistance, such as ZrO2-Y2O3 (YSZ) • Expected for inert fuel matrix, transmutation target of MA and LLFP, etc.
Characteristics of fully stabilized zirconia Empty site in anion sublattice ©•• 2008 Materials Research Society Different diffusivity between cations and anions • Large difference in mass (ex. MZr=91.2, MO=16.0)
⇒ induce a large difference in the displacement rate under irradiation when PKA energy is rather low
Elastic displacement cross section for zirconia
Cross section (barn)
10 0
10
© 2008 Materials Research Society 1
Zr : Ed = 28 eV Zr : Ed = 40 eV Zr : Ed = 48 eV
0.1
O : Ed = 16 eV O : Ed = 20 eV O : E d = 28 eV
0 .0 1 0. 1
1
10
Electron energy (MeV)
Electron irradiation less than ~1 MeV is a selective displacement condition for oxygen sublattice.
Objective To clarify the characteristic features of defect clusters in oxides with fluorite structure under electron irradiation (producing rather low energies of PKAs).
⇒
© 2008 Materials Research Society formation of charged dislocation loops consist of O ions Materials: z Fully stabilized zirconia (ZrO2-Y2O3) z Ceria (CeO2) z Calcium fluorite (CaF2)
Defect clusters in YSZ K. Yasuda et al, JNM 319 (2003) 74.
—
300 keV O+ions: 5.1x1017 ions/m2 at 470 K
– 200 keV electrons at 370 K
© 2008 Materials Research Society
500 nm
Growth process of the defect clusters φ～1021 e/m2/s
B=
© 2008 Materials Research Society
500 nm
Growth process of radiation defects in YSZ K. Yasuda et al, JNM 319 (2003) 74.
a
b
c
d
e
© 2008 Materials Research Society 0.00 s
174.00 s
288.35 s
388.30 s
388.35 s
f
g
h
i
j
521.00 s
500 nm 689.00 s
408.00 s
445.00 s
497.00 s
Dislocation loops in CeO2 K. Yasunaga et al, NIMB 250 (2006) 114.
MCe=140 amu, MO=16 amu
200 keV
500 keV
(at 300 K. Φ ~ 3×1026 e/m2)
750 keV
1000 keV
1250 keV
© 2008 Materials Research Society
100 nm Dislocation loops with same nature are formed below 1250 keV. B // , on (111) planes
HRTEM of dislocation loop on (111) plane K. Yasunaga et al, submitted to NIMB
[111]
Ce ion O ion
[211] [011]
© 2008 Materials Research Society 0.31 nm
0.31 nm
B=[011]
Stacking sequence of {111} in fluorite structure
Planer defect has stacking fault with extra half plane of O-ions. ⇒ 1/9{111}
Electron irradiation with 2 and 3 MeV at UHVEM Center of Osaka University K. Yasunaga et al, submitted to NIMB
Data Loading...
