1 T. CharpentierActinet Workshop, September 23th, 2005 A Solid State NMR Study of a Mixed Alkali...
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Transcript of 1 T. CharpentierActinet Workshop, September 23th, 2005 A Solid State NMR Study of a Mixed Alkali...
T. CharpentierActinet Workshop, September 23th, 2005 1
A Solid State NMR Study of
a Mixed Alkali Aluminoborosilicate Glass Structure
and its Evolution Under Irradiation
T. Charpentier, M. Gaillard, D. Sakellariou, J. Virlet
Laboratoire de Structure et Dynamique par Résonance Magnétique
Laboratoire Claude Fréjacques, URA 331 CEA / CNRSService de Chimie Moléculaire
CEA Saclay, France.
N. Ollier, B. BoizotLaboratoire des Solides Irradiés
CEA-CNRS-Ecole Polytechnique, France.
T. CharpentierActinet Workshop, September 23th, 2005 2
Overview of the study
• Understanding the effects of ionizing radiations (here e-) on structural changes of nuclear waste glasses, in order to predict the modification of the glass during storage.
• Simulation of the dose (auto) irradiation accumulated during storage by external electron irradiations: Van de Graaff accelarator,1.8 MeV, 20 A beam, ~ 1GGy dose.
• Use of simplified borosilicate glasses (mol.%)
63.47 SiO2- 16.8 B2O3 – 4.04 Al2O3 – 2.35 ZrO2 – 13.34 A2O
A2O =
1) x Na2O - (1-x) Li2O
2) x Na2O - (1-x) K2O
Vitrified waste (CSD-V)
T. CharpentierActinet Workshop, September 23th, 2005 3
(Microscopic) Structural changes induced by irradiations
• Increase of glass polymerization : Si(Q2)Si(Q3)
• Increase of boron in trigonal environments : BO4 BO3
• Formation of molecular oxygen
• Production of paramagnetic defects
B. Boizot et al., NIM B 166-167, (2000) 500N. Ollier et al., JNCS 323, (2003) 200.
Most of the structural changes are assigned to the migration of alkali Segregation of alkali under irradiation ?
These changes are less important in complex glass composition (close to the French Nuclear glass SON68) than simple ones : this could be
explained by the decrease of the alkaline ions mobility
The Mixed Alkali Effect(decreases considerably the alkali motion ) / irradiations
0.1 à 3.5MeV
~1 mm
~ cm
~ 100 %
<< 1 dépl .
{
~ 100 %
< 1 dépl .
{
0.1 à 3.5
MeV
~1 mm
0.1 à 3.5
MeV
~1 mm
0.1 à 3.5MeV
~1 mm
0.1 à 3.5MeV
0.1 à 3.5MeV
~1 mm
~ cm
~ cm
~ 100 %
<< 1 dépl .
{
~ 100 %
< 1 dépl .
{
~ 100 %
<< 1 dépl .
{
~ 100 %
<< 1 dépl .
{
~ 100 %
< 1 dépl .
{
~ 100 %
< 1 dépl .
{
T. CharpentierActinet Workshop, September 23th, 2005 4
The Mixed Alkali Effect
550
560
570
580
590
600
610
620
0 0,2 0,4 0,6 0,8 1
mol.% (Na2O/Na2O+K2O)
Tg
(°C
)
Electrical conductivity (300°C)
-12
-11
-10
-9
-8
0 0.2 0.4 0.6 0.8 1
Na/LiNa/K
Log
m)-1
mol % (Na2O)/(Na
2O+Z)
Tg
MAE : significant decrease of the ionic conductivityCan the MAE cause a reduction of alkali migration under irradiation ?
T. CharpentierActinet Workshop, September 23th, 2005 5
MAS NMR of Quadrupolar Nuclei
TB 05.70
TB 75.110
0B
+3/2
+1/2
-1/2
-3/2
Central transition
2/3I
parameterasymmetry r quadrupola :
constant couplingr quadrupola : 31 ,
shift chemical isotropic :
: shift chemical
2
00
20
2
Q
iso
Qiso
C
CPB
P
220
2/11
: fields) (two glassesFor Qiso P
T. CharpentierActinet Workshop, September 23th, 2005 6
11B (I=3/2) MAS NMR
TB 05.70 TB 75.110
T. CharpentierActinet Workshop, September 23th, 2005 7
11B MAS / MQMAS NMR
MAS (1d)
MQMAS (2d)
T. CharpentierActinet Workshop, September 23th, 2005 8
11B MQMAS NMR
BO32 sites
BO42 sites
T. CharpentierActinet Workshop, September 23th, 2005 9
11B MAS NMR
B
OB
O O
O
O
B
OB
O O
O
O
B
OB
O
B
O
O
O
O
B
OB
O
B
O
O
O
O
T. CharpentierActinet Workshop, September 23th, 2005 10
11B MAS NMR : Mixed Alkali Effect
T. CharpentierActinet Workshop, September 23th, 2005 11
11B MAS NMR : Mixed Alkali Effect
Non-linear variation of the BO3/BO4 ratio
Na/Li : BO3/BO4 minimum
Na/K : BO3/BO4 maximum
T. CharpentierActinet Workshop, September 23th, 2005 12
11B MAS NMR : irradiation effects Na/Li
BO4 to BO3 conversion
T. CharpentierActinet Workshop, September 23th, 2005 13
11B MAS NMR : irradiation effects Na/K
BO4 to BO4/BO3 conversion No conversion
T. CharpentierActinet Workshop, September 23th, 2005 14
27Al MAS NMR
KCNaCLiC QQQ
T. CharpentierActinet Workshop, September 23th, 2005 15
27Al MAS NMR : Mixed Alkali Effect
AlO4- : Na+ preferential charge compensator ?
T. CharpentierActinet Workshop, September 23th, 2005 16
27Al MAS NMR : irradiation effects Na/K,Na/Li
Cq increases (site distortion increase). MAE : minimized effect
K,Na Na,Li
T. CharpentierActinet Workshop, September 23th, 2005 17
27Al MAS NMR : Mixed Alkali Effect Na/K,Na/Li
Analytical model for f(Cq,nq) : Gaussian Isotropic Model (Cjzjek)
T. CharpentierActinet Workshop, September 23th, 2005 18
27Al MAS NMR : Mixed Alkali Effect Na/K,Na/Li
T. CharpentierActinet Workshop, September 23th, 2005 19
29Si MAS NMR
Na,KLi,Na
T. CharpentierActinet Workshop, September 23th, 2005 20
29Si RAMAN : irradiation effects Na/K,Na/Li
1000 1200
0
3000
6000
1000 1200
0
5000
1000 1200
0
4000
1000 1200
0
5000
1000 1200
0
3000
6000
1000 1200
0
5000
50 Na
25 Na
75 Na 60 Na
100 K
40 Na
1000 1200
0
2000
1000 12000
4000
1000 12000
2000
4000
1000 12000
3000
0 Na
Raman shift (cm-1)
75 Na
Raman shift (cm-1)
25 Na
Raman shift (cm-1)
50 Na
Raman shift (cm-1)
Na/Li
Na/K
50/50
Q2
Q3
Irradiated
Pristine
MAE: modifier migration blocked
Q2Q3
T. CharpentierActinet Workshop, September 23th, 2005 21
29Si MAS NMR / RAMAN
900 1000 1100 12000
3000
6000
Q3
Q2
50/50 Irradiated glassPristine glass
Inte
nsity
(a.
u)
Raman shift (cm-1)
Q2
Q3
Na/Li : Stable polymerization Li : Polymerization increase
1000 12000
2000
Li5a100 % Li
Décalage Raman (cm-1)
T. CharpentierActinet Workshop, September 23th, 2005 22
23Na NMR
Localisation of the alkali after the migration processes
1) migration to the surfaceXPS : No
2) bulk segregation
Can NMR provides measurements to detect it ?
Static (Non-rotating ) sample approach : Relaxation Time Measurment
and SEDOR NMR
T. CharpentierActinet Workshop, September 23th, 2005 23
23Na NMR : longitudinal relaxation
180 90
eqM
0M
rectM
rect
inversion recovery experiment
eqM
32
1
expT
tBA
T. CharpentierActinet Workshop, September 23th, 2005 24
23Na NMR : irradiation effects Na/Li
Na-Na1
111
intersite1
intersite1intrasite11
D
DQ
T
TTT
T. CharpentierActinet Workshop, September 23th, 2005 25
23Na Spin Echo / SEDOR NMR
90
T T
E(T)23Na
7Li
E(T) (Hahn Echo): Na-Na dipolar interactions
180
E(T) (SEDOR): Na-Na + Na-Li dipolar interactions
180
T. CharpentierActinet Workshop, September 23th, 2005 26
23Na Spin Echo / SEDOR NMR
ji ijr
M62
1
LiNaNaNa MM 22
NaNaM 2
T. CharpentierActinet Workshop, September 23th, 2005 27
23Na Spin Echo/SEDOR NMR : irradiation effects Na/Li
: decrease of Na-Li dipolar interactions Na clusterization ?
T. CharpentierActinet Workshop, September 23th, 2005 28
Conclusion
MAE on the glass network structure
Na/K : BO3/BO4 minimum - Na/Li : BO3/BO4 maximum
MAE / irradiation effects
Na/K blocks the migration of BO4 compensators
Na/Li blocks the migration of modifiers
AlO4 – stable : site distortion increase
Na preferential charge compensator ?
Na clusterization?
Ionic Irradiation (Aun+) (underway)N.Ollier et al, Journal of Physics : Condensed Matter 16 (2004) 7625.N.Ollier et al, Journal of Non-Crystalline Solids 341, (2004) 26.
T. CharpentierActinet Workshop, September 23th, 2005 29
Perpectives
0B
NMR of active materials :Auto-irradiation effects
Special containment (rotor) systemSee D. Sakellariou
T. CharpentierActinet Workshop, September 23th, 2005 30
Perpectives : Heteronuclear correlation spectrosocopy
Static sample NMR can be useful