SYNTHESIS OF NIOBIUM DOPED ZINC
BOROSILICATE GLASS-CERAMICS
N. Fernandes*, A. Lopes, M. Lima, J.P. Veiga,
R. Monteiro**
Structural Materials, *[email protected]; **[email protected]
Summary
•
Objectives
•
Materials and methods
•
Results
•
Conclusions
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Objectives
•
Synthesis of the glasses Nb-ZBS
•
Study of the effect of Nb2O5 addition:
3

glass transition and crystallization temperatures

crystaline phase formation

microstructure
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Main applications
•
Transparent Nb doped ZBS glasses and glass
ceramics have photoluminescent behaviour.
•
Glass-ceramics based on Nb dopped ZBS have
interesting dielectric characteristics.
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Materials and Methods
Mixing the reagents
Name
%mol SiO2
%mol B2O3
%mol ZnO
1S
10
30
60
2S
20
20
60
Temp. (ºC)
Time (min)
Vel. (ºC/min)
Melting
Pouring and annealing
Name
%mol
Nb2O5
10
1S-0
0
2S-0
0
1S-2.5
2.5
2S-2.5
2.5
1S-5
5
2S-5
5
1S-7.5
7.5
2S-7.5
7.5
1S-10
10
2S-10
10
Glass characterization
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
1350 Name
120 %mol Nb2O5
Materials and Methods
XRD
DSC
Glass-ceramics synthesis
Glass-ceramics
characterization
XRD
SEM
Glass characterization
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Results – XRD of glasses
10
20
30
40
50
60
2
Representative XRD patterns of the glasses
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Results – DSC of glasses
538
630
750
950
570
670
740
620
940
exo
1S - 10
606
541
932
706
648
606
933
1S - 7.5
560
660
730
Series 1S
689
648
648
545
723
606
endo
oo
oo
Tm
C)
Tg
Tp2
Tp1
Tc ((( C)
C)
610
930
933
720
1S
550
650- 5
548
648
742
606
930
600
920
710
1S
- 2.5
540
640
648
554
700
590
910
742
606
937
1S - 0
530
630
690
580
900
450
500
0,0
0,0
550
2,5
2,5
600
650
5,0
5,0
700
750
mol% Nb
Nb22O
O55
7,5
7,5
Temperature (ºC)
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
800
10,0
850
900
950
Results – DSC of glasses
710
542
700
770
580
900
820
2S
- 10
660
exo
880
760
690
570
860 2S
650
750
oo
Tg
((C)
Tp2
Tp1
Tc
C)
Tm(ºC)
endo
725
546
820
7.5
840
680
560
667
550
740
640
820
820
672
670
550
730
800
630
780
2S
720 660
540
2.5
760
620
710 2S
740
650
530
0
763
820
556
641
765
680
566
0,0
500
736
636
2S - 5
450
649
2,5
550
600
5,0
650
700
mol% Nb2O5
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
820
7,5
750
Temperature (ºC)
9
Series 2S
10,0
800
850
900
Results – XRD of glass-ceramics
ZnNb2O6
Zn3B2O6
1S-5
1S-0
680ºC/1h
680ºC/1h
620ºC/1h
620ºC/1h
10
20
30
40
50
2
60
10
20
30
40
2
ZnNb2O6
1S-10
680ºC/1h
620ºC/1h
10
20
30
40
2
10
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
50
60
Results – XRD of glass-ceramics
Zn3B2O6
1S-0
Zn3B2O6
1S-0
680ºC/1h
620ºC/1h
680ºC/1h
10
20
30
40
50
60
2
620ºC/1h
10
20
30
40
2
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
Results – XRD of glass-ceramics
ZnNb2O6
Zn3B2O6
1S-5
1S-0
680ºC/1h
680ºC/1h
620ºC/1h
620ºC/1h
10
20
30
40
50
2
60
10
20
30
40
2
ZnNb2O6
1S-10
680ºC/1h
620ºC/1h
10
20
30
40
2
12
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
50
60
Results – XRD of glass-ceramics
ZnNb2O6
1S-5
ZnNb2O6
1S-5
680ºC/1h
620ºC/1h
680ºC/1h
10
20
30
40
50
60
2
620ºC/1h
10
20
30
40
2
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
Results – XRD of glass-ceramics
ZnNb2O6
Zn3B2O6
1S-5
1S-0
680ºC/1h
680ºC/1h
620ºC/1h
620ºC/1h
10
20
30
40
50
2
60
10
20
30
40
2
ZnNb2O6
1S-10
680ºC/1h
620ºC/1h
10
20
30
40
2
14
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
50
60
Results – XRD of glass-ceramics
ZnNb2O6
1S-10
680ºC/1h
ZnNb2O6
1S-10
680ºC/1h
620ºC/1h
620ºC/1h
10
20
30
40
50
2
10
20
30
40
2
15
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
60
Results – phase formation
Nb2O5
16
%mol Nb2O5
620 ºC
680ºC
0
-
Zn3B2O6
5
ZnNb2O6
ZnNb2O6
10
ZnNb2O6
ZnNb2O6
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Results – XRD of glass-ceramics
ZnNb2O6
2S-10
Zn3B2O6
765ºC/1h
712ºC/1h
690ºC/1h
10
20
30
40
2
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
50
60
Results – phase formation
Temperature
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Temp. (ºC)
Phase
690
ZnNb2O6
712
ZnNb2O6/Zn3B2O6
765
ZnNb2O6/Zn3B2O6
Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Results – SEM of glass-ceramics
690ºC/1h
712ºC/1h
765ºC/1h
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Nuno Fernandes - Jornadas do CENIMAT
23-06-2014
Conclusions
•
The Nb2O5 addition causes:

decreasing of glass transition;

decreasing of crystallization temperatures;

formation of Zinc Niobate (ZnNb2O6) as the predominant phase
and Zinc Borate (Zn3B2O6) as secondary phase;
•
In order to obtain nanostructured glass-ceramics
Nb2O5 addition should be <5 mol% and the thermal
treatments should be under 620ºC.
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23-06-2014
Thank you.
Nuno Fernandes Jornadas do CENIMAT 2306-2014
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