Solid State NMR Characterisation
of Borosilicate Glasses for
Automobile Obscuration Enamels
Jo Higgs
Contents
• Background – Project
– Glass Structure
• Model Samples
• Other Work
– Glasses containing Fluorine
– Crystallising Samples
– Flame Spray Pyrolysis
Background
Johnson Matthey Windscreen Glasses
• Enamel
– Windscreen glass with black pigment
– Shield glue from UV light
– Design
• New Product
– Must pass new industry acid test
– Increase acid resistance
– Firing temp. ~ 600°C
Background
Glass Structure
• Amorphous solid without long
range periodic atomic arrangement.
• Structural units
– depend on the composition
– affect the physical properties.
• Formed of oxides
– network formers e.g. SiO2 and B2O3
– network modifiers e.g. Na2O
– intermediates
Si
O
Na
Zinc & Bismuth Model Samples
• Aim: Study the effects of Zn and Bi on the structure of
sodium borosilicate glass
• Composition:
• Contain SiO2, B2O3, Na2O and
ZnO or Bi2O3
• Si + Na ~ constant for all samples
• B + Zn or Bi ~ 21 mol%
• Zn / Bi increases as B decreases
Experiments:
• Single pulse:
11B, 23Na, 29Si
• 11B MQMAS
• 11B DOR
(one sample)
• Research question: Bi and Zn substitute B in the
compositions – do they also substitute it in the glass
network?
Model Samples –
Sample
containing
3% zinc
11B
11.75 T
7.05 T
10 kHz
10 kHz
Bismuth Samples
Zinc Samples
80
80
11.7 T
7.05 T
70
60
60
4
70
% BO
% BO4
11.7 T
7.05 T
50
40
50
40
30
30
0
5
10
15
% Bi2O3 20
0
5
10
15
% ZnO
20
11B
Base glass: contains
no bismuth or zinc
– MQMAS & DOR
mp3qzfil
14.1 T
t1
t1
π/2
π/2
t2
13.9 kHz
+3
+2
+1
p= 0
-1
-2
-3
DOR
14.1 T
2 BO4
Sites
BO3
BO4
Sideband
BO4
Sideband
Model Samples –
Sample
containing
3% zinc
23Na
14.1 T
7.05 T
10 kHz
20 kHz
Bismuth Samples
Zinc Samples
10
4
6
4
2
0
-2
-4
14.1 T
7.05 T
-6
Isotropic Chemical Shift (ppm)
Isotropic Chemical Shift (ppm)
8
2
0
-2
-4
-6
14.1 T
7.05 T
-8
-8
0
5
10
15
20
25% Bi O 30
2 3
35
0
5
10
15
% ZnO
20
25
Model Samples –
Bismuth Samples
Zinc Samples
3.7
14.1 T
7.05 T
3.3
3.2
3.1
3
2.9
2.8
0
5
10
15
20
% Bi2O3
25
30
35
<CQ> Centre of CQ Distribution (MHz)
<CQ> Centre of CQ Distribution (MHz)
3.5
3.4
23Na
14.1 T
7.05 T
3.6
3.5
3.4
3.3
3.2
3.1
3
2.9
2.8
0
5
10
15
% ZnO
20
25
Model Samples –
Sample
containing
18 % zinc
Predicted Q species:
• Q0 or Q1 at ~ – 83 ppm
• Q1 or Q2 at ~ – 93 ppm
• Q3 at ~ – 104 ppm
Bismuth Samples
Zinc Samples
-88
Weighted Average Chemical Shift (ppm)
Weighted Average Chemical Shift (ppm)
-84
29Si
-86
-88
-90
-92
-94
-96
-98
-100
-90
-92
-94
-96
-98
-100
-102
-102
0
5
10
15
20
25
30% Bi2O335
0
5
10
15
20
% ZnO 25
Model Samples – Conclusions
Roles of bismuth and zinc:
•
11B
•
23Na
•
29Si
– Bi and Zn not replacing B in the network
– Bi and Zn acting as network modifiers
– Network becomes less connected with higher Bi or Zn content
Further work:
•
2D 29Si – need enriched samples
•
Samples with both bismuth and zinc
Fluorinated Glass Samples
11B
11.75 T
10 kHz
Samples:
H01 – 0 mol% F
H02 – 5 mol% F
H03 – 10 mol% F
H03
H02
Peaks:
1 – KF or Na2SiF6 ?
3
4
2 – unknown
3 – LiF
4 – NaF
* – sidebands
19F
11.75 T
30 kHz
*
1
2
*
*
*
30
H03
*
*
*
H01
20
10
0
-10
23Na
*
Impurity
denoted by *
NaF at 7.2ppm
ppm
-20
14.1 T
10 kHz
*
H03
*
H02
H02
H01
-100
-150
-200
-250
-300
ppm
30
20
10
0
-10
-20
-30
-40
ppm
Crystallising Samples
11B
11.75 T
10 kHz
29Si
7.05 T
4 kHz
JM1
JM1
1a
1a
1b
1b
1c
1c
1d
1d
30
20
10
0
-10
-20
ppm
JM1 – commercial
1a – heat treated
1b – heat treated and seeded
1c – no iron
1d – JM1 made on small scale
Crystalline phases:
- Bi2SiO5 Bismuth
monosilicate
- Eulytite Bi4(SiO4)3
Flame Spray Pyrolysis
• Produces nanoparticles
• One-step process
• Investigate effect on structure
A - soda-lime
B - borosilicate
23Na
14.1 T
10 kHz
A
B
30
20
10
0
-10
-20
-30
-40 ppm
Acknowledgments
• Supervisors
– Mark E. Smith, John V. Hanna
• Industrial Supervisors
– Peter Bishop, Jon Booth, Hong Zheng
• NMR Group
– Nathan Barrow, Andy Howes
Thank you for listening