SYNTHESIS OF NIOBIUM DOPED ZINC BOROSILICATE GLASS …• Transparent Nb doped ZBS glasses and glass...

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

Nuno Fernandes - Jornadas do CENIMAT

23-06-2014 2

Objectives

• Synthesis of the glasses Nb-ZBS

• Study of the effect of Nb2O5 addition:

Nuno Fernandes - Jornadas do CENIMAT 23-06-2014

3

glass transition and crystallization temperatures

crystaline phase formation

microstructure

Main applications

• Transparent Nb doped ZBS glasses and glass

ceramics have photoluminescent behaviour.

• Glass-ceramics based on Nb dopped ZBS have

interesting dielectric characteristics.


4

Materials and Methods


5

Mixing the reagents

Glass characterization

Name %mol SiO2 %mol B2O3 %mol ZnO

1S 10 30 60

2S 20 20 60

Name %mol Nb2O5

1S-0 0

1S-2.5 2.5

1S-5 5

1S-7.5 7.5

1S-10 10

Name %mol Nb2O5

2S-0 0

2S-2.5 2.5

2S-5 5

2S-7.5 7.5

2S-10 10

Melting Vel. (ºC/min) Temp. (ºC) Time (min)

10 1350 120

Pouring and annealing

Materials and Methods


6

Glass characterization

XRD

DSC

SEM

Glass-ceramics synthesis

Glass-ceramics characterization

XRD

Results – XRD of glasses


7

10 20 30 40 50 60

2

Representative XRD patterns of the glasses

Results – DSC of glasses


8

endo

450 500 550 600 650 700 750 800 850 900

Temperature (ºC)

1S - 10

1S - 2.5

1S - 5

1S - 0

1S - 7.5exo

950

554

548

545

541

538

606

606

606

606

606

648

648

648

648

648

742

742

723

706

689

937

930

933

933

932

0,0 2,5 5,0 7,5 10,0

530

540

550

560

570

T

g (

oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

580

590

600

610

620

630T

c (o

C)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

630

640

650

660

670

Tp

1 (

oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

690

700

710

720

730

740

750T

p2

(oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

900

910

920

930

940

950T

m (

oC

)

mol% Nb2O

5

Series 1S

endo

450 500 550 600 650 700 750 800 850 900

Temperature (ºC)

exo

2S - 0

2S - 2.5

2S - 5

2S - 7.5

2S - 10

Results – DSC of glasses


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566

556

550

546

542

649

641

636

680

672

667

765

763

736

725

710

820

820

820

820

820

0,0 2,5 5,0 7,5 10,0

530

540

550

560

570

580T

g (

oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

620

630

640

650

660

Tc

(oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

650

660

670

680

690

700T

p1

(oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

710

720

730

740

750

760

770T

p2

(oC

)

mol% Nb2O

5

0,0 2,5 5,0 7,5 10,0

740

760

780

800

820

840

860

880

900

Tm

(ºC

)

mol% Nb2O

5

Series 2S

Results – XRD of glass-ceramics


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10 20 30 40 50 60

ZnNb2O

6

2

1S-5

620ºC/1h

680ºC/1h

10 20 30 40 50 60

Zn3B

2O

6

2

620ºC/1h

680ºC/1h

1S-0

10 20 30 40 50 60

ZnNb2O

6

2

1S-10

620ºC/1h

680ºC/1h



11

10 20 30 40 50 60

Zn3B

2O

6

2

620ºC/1h

680ºC/1h

1S-0

10 20 30 40 50 60

Zn3B

2O

6

2

620ºC/1h

680ºC/1h

1S-0



12

10 20 30 40 50 60

ZnNb2O

6

2

1S-5

620ºC/1h

680ºC/1h

10 20 30 40 50 60

Zn3B

2O

6

2

620ºC/1h

680ºC/1h

1S-0

10 20 30 40 50 60

ZnNb2O

6

2

1S-10

620ºC/1h

680ºC/1h



13

10 20 30 40 50 60

ZnNb2O

6

2

1S-5

620ºC/1h

680ºC/1h

10 20 30 40 50 60

ZnNb2O

6

2

1S-5

620ºC/1h

680ºC/1h



14

10 20 30 40 50 60

ZnNb2O

6

2

1S-5

620ºC/1h

680ºC/1h

10 20 30 40 50 60

Zn3B

2O

6

2

620ºC/1h

680ºC/1h

1S-0

10 20 30 40 50 60

ZnNb2O

6

2

1S-10

620ºC/1h

680ºC/1h



15

10 20 30 40 50 60

ZnNb2O

6

2

1S-10

620ºC/1h

680ºC/1h

10 20 30 40 50 60

ZnNb2O

6

2

1S-10

620ºC/1h

680ºC/1h

Results – phase formation


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%mol Nb2O5 620 ºC 680ºC

0 - Zn3B2O6

5 ZnNb2O6 ZnNb2O6

10 ZnNb2O6 ZnNb2O6

Nb2O5



17

10 20 30 40 50 60

2

ZnNb2O

6

Zn3B

2O

6

2S-10

765ºC/1h

712ºC/1h

690ºC/1h

Results – phase formation


18

Temp. (ºC) Phase

690 ZnNb2O6

712 ZnNb2O6/Zn3B2O6

765 ZnNb2O6/Zn3B2O6

Temperature

Results – SEM of glass-ceramics


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690ºC/1h 712ºC/1h

765ºC/1h

Conclusions


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• 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

Nuno Fernandes Jornadas do CENIMAT 23-06-2014

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Thank you.

SYNTHESIS OF NIOBIUM DOPED ZINC BOROSILICATE GLASS …• Transparent Nb doped ZBS glasses and glass...

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Transcript of SYNTHESIS OF NIOBIUM DOPED ZINC BOROSILICATE GLASS …• Transparent Nb doped ZBS glasses and glass...