Emilie Boulay , Céline Ragoen , Stéphane Godet

Influence of amorphous phase separation on the crystallization behavior of glass-ceramics in the

BaO-TiO2-SiO2 system

Emilie Boulay, Céline Ragoen, Stéphane GodetULB, 4MAT Department, CP194/3, 87 Av. Buyl, 1050 Brussels, Belgium

Crystallization 2012 Goslar, Germany25th September 2012

APS role BaO-TiO2-SiO2 Results & Discussions Conclusions Perspectives

Outline

Influence of phase separation on crystallization

Motivations

The BaO-TiO2-SiO2 system

Results & Discussion

Conclusions

Perspectives

2Crystallization 2012 - Goslar


Amorphous phase separation (APS)

Well known in glass systems

APS = matrix + droplets due to liquid immiscibility

3

APS role

?A

BC

D1

D2

Crystallization 2012 - Goslar


Amorphous phase separation (APS)

Well known in glass systems

APS = matrix + droplets due to liquid immiscibility

Shift in composition + creation of interfaces

4

Interfaces

In the droplets

In the matrix

APS role

Shift

I. Gutzow, J. Schmelzer, “The vitrous state: thermodynamics, structures, rheology and crystallization, Springer, 1995



Possible effects of APS on crystallization

[1] Scherrer, G W et Uhlmann, D R. , 1976 [8] ] Harper, H et McMillan, P W. , 1972[2] Hammel, J J. , 1966 [9] Bhattacharyya, S, et al., 2009[3] Boulay, 2011 [10] Tomozawa, M, et al., 1990[4] K. Nakagawa, T. Izumitani, 1969 [11] Hijiya, H et al., 2008[5] James, P F et Ramsden, A H. , 1984 [12] Li Z., 1985[6] Katsumata, K, et al., 2004[7] Jiazhi, L et Chih-yao, F. , 1986

5

No influence Shift matrix Shift droplets Interfaces- Interfacial Energy- Diffusion zone

Na2O-SiO2 [1] BaO-SiO2 [5] LaF3-Na2O-Al2O3-SiO2 [9] Li2O-SiO2 [10]

Na2O-CaO-SiO2 [2][3] TiO2-SiO2 [6] BaO-SiO2-TiO2 [11]

Li2O-SiO2 [4] MgO-Al2O3-SiO2-TiO2 [7]ZnO-Al2O3-SiO2 [7]

ZnO-Al2O3-SiO2-ZrO2 [7]

Interfaces do not promote crystallization

[3] [4] [12]

Li2O-SiO2-P2O5 [8]

APS role



Possible effects of APS on crystallization

5

No influence Shift matrix Shift droplets Interfaces- Interfacial Energy- Diffusion zone

Na2O-SiO2 [1] BaO-SiO2 [5] LaF3-Na2O-Al2O3-SiO2 [9] Li2O-SiO2 [10]

Na2O-CaO-SiO2 [2][3] TiO2-SiO2 [6] BaO-SiO2-TiO2 [11]

Li2O-SiO2 [4] MgO-Al2O3-SiO2-TiO2 [7]ZnO-Al2O3-SiO2 [7]

ZnO-Al2O3-SiO2-ZrO2 [7]

Interfaces do not promote crystallization

[3] [4] [12]

Li2O-SiO2-P2O5 [8]

APS role

Systematic study of prior amorphous phase separation effect on crystallization in the BaO-TiO2-SiO2 system:

- Interfaces: debated in literature- Photoluminescence properties



The BaO-TiO2-SiO2 system

This glass system exhibits APS by the presence of a large miscibility gap in the silica corner

The exact miscibility gap location is unknown

Crystal phase near immiscibility: fresnoite (2BaO.TiO2.2SiO2)

* Hijiya et al., “Effect of phase separation on crystallization of glasses in the BaO-TiO2-SiO2 system”, 2009

?

BaO-TiO2-SiO2

Crystallization 2012 - Goslar 6


Technical interests of fresnoite

Fresnoite exhibits blue/white photoluminescence (PL) under ultraviolet excitation

PL effect can be optimized by heat treatments on the stoichiometric composition

Photoluminescence

T. Komatsu, “Effect of heat treatment temperature on the optical properties of Ba2TiSi2O8 nanocrystallized glasses”, 2005

Excitation at 254 nmResponse at 470 nm

7

BaO-TiO2-SiO2



Possible enhancement of optical properties

No stoichiometric compositions show also PL effect (=254 nm)

Hijiya (2008) suggested phase separation may have an influence on crystallization and PL effect

Hijiya et al., “Effect of phase separation on crystallization of glasses in the BaO-TiO2-SiO2 system”, 2009

Stoich. Non stoich.

APS

[211] intensity vs [002]: orientation PL effect

8

SiO2↑

BaO-TiO2-SiO2


Material investigated – Fresnoite-SiO2 line

Quenched after melting


FRES

NoAPSAPS

9


FRES: stoichiometric composition

NoAPS: non stoichiometric composition outside the miscibility gap

APS: non stoichiometric composition inside the miscibility gap

Mixing powder + melting (1500-1560°C, 3H)Air quenched + annealed (600C, 10H)

Water-quenched after melting


Results & Discussions


Crystallization mechanism by DSC• Effect of quenching rate• Effect of composition

Microstructure by SEM• Morphologies at early and final stages of crystallization

Morphological orientation:• Large scale: XRD• Small scale: EBSD (FEG – SEM) and ACOM (TEM)




APS air-quenched versus APS water-quenched

No prior APS (APS)

11

Prior APS (APS)




[#] Instrument [1] STA 409 PC/PG[2] STA 409 PC/PG[3] STA 409 PC/PG[4] STA 409 PC/PG[5] STA 409 PC/PG

FileBTS-0_25-112_40Cm.ssvBTS-0_25_112_1Cm.ssvBTS-0_25_112_10Cm.ssvBTS-0_25_112_20Cm.ssvBTS-0_25-112_30Cm.ssv

Date2012-09-112012-09-142012-09-172012-09-142012-09-11

IdentityBTS-0-25-112-30CmBTS 0 25-112 1CmBTS 0 25-112 10CmBTS 0 25-112 20CmBTS-0-25-112-30Cm

SampleBTS-0-25-112-30CmBTS 0 25-112 1CmBTS 0 25-112 10CmBTS 0 25-112 20CmBTS-0-25-112-30Cm

Mass/mg61.80062.30062.20061.80062.800

Segment1/11/11/11/11/1

Range20/40.0(K/min)/100025/1.0(K/min)/100025/10.0(K/min)/100025/20.0(K/min)/100030/30.0(K/min)/1000

AtmosphereAir/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---Air/60 / ---/--- / He : 20ml/min/---

Corr.002002002002002

500 600 700 800 900 1000Temperature /°C

0.0

0.1

0.2

0.3

0.4

0.5

DSC /(uV/mg)

Main 2012-09-20 19:27 User: Schind

Peak: 782.2 °C

Peak: 828.3 °C

Peak: 843.5 °C

Peak: 850.9 °C

Peak: 856.5 °C

[1]

[2]

[3][4][5]

exo

[#] Instrument [1] STA 409 PC/PG[2] STA 409 PC/PG[3] STA 409 PC/PG[4] STA 409 PC/PG

FileBTS27-1100C-10Cmin.ssvBTS27-1100C-10Cmin-2.ssvBTS27-1140Cmin-10Cmin-4.ssvBTS27-1300Cmin-10Cmin-3.ssv

Date2011-12-162011-12-162011-12-142011-12-08

IdentityBTS-27-1100C-10CminBTS-27-1100C-10Cmin-2BTS-27-1140C-10Cmin-4BTS-27-1300C-10Cmin

SampleBTS27-1100C-10CminBTS27-1100C-10Cmin-2BTS-27-1140C-10Cmin-4BTS27-1300C-10Cmin

Mass/...61.87061.82050.93069.500

Segme...1/11/11/11/1

Range40/10.0(K/min)/110035/10.0(K/min)/110025/10.0(K/min)/114025/10.0(K/min)/1300

AtmosphereHe/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---

Co...002002002002

700 750 800 850 900 950 1000 1050 1100 1150Temperature /°C

-0.10

-0.05

0.00

0.05

0.10

DSC /(uV/mg)

Main 2012-09-20 16:10 User: Schind BTS0-25-112.ngb

Peak: 932.9 °C Peak: 959.5 °C

Peak: 993.3 °C

Peak: 1055.9 °C

Inflection: 757.5 °C

[1][2][3]

[4]

exo

[#] Instrument [1] STA 409 PC/...[2] STA 409 PC/...[3] STA 409 PC/...[4] STA 409 PC/...

FileBTS-0_200-850_10Cm....BTS-0_850_10Cm-.ssvBTS-0_25_112_10Cm.s...BTS-0_112-200_10Cm....

Date2012-09-...2012-03-...2012-09-...2012-09-...

IdentityBTS-0-200-800-10CmBTS0 sup850 10Cm 10...BTS 0 25-112 10CmBTS0- 112-200-10Cm

SampleBTS-0-200-800-10CmBTS0 sup850 10Cm 10...BTS 0 25-112 10CmBTS0- 112-200-10Cm

Mass...62.600103.0...62.20064.000

Se...1/11-...1/11/1

Range100/10.0(K/min)/100020/50.0(K/min)/550/10.0(K/min)/1...25/10.0(K/min)/100085/10.0(K/min)/1000

AtmosphereAir/60 / ---/--- / He : 20ml/mi...He/60 / ---/--- / He : 20ml/mi...He/60 / ---/--- / He : 20ml/mi...He/60 / ---/--- / He : 20ml/mi...

C...0...0...0...0...

600 700 800 900 1000 1100Temperature /°C

0.00

0.05

0.10

0.15

0.20

DSC /(uV/mg)


Peak: 824.3 °C

Peak: 829.4 °C

Peak: 830.7 °C

Peak: 828.3 °C

[1] [2][3]

[4]

exo

FRES

Cristallization mechanism – Effect of composition

APS

12

112<G<200µm

G>850µm

200<G<850µm

25<G<112µm

25<G<112µm

10°C/min


FileBTS27-1100Cmin-40Cmin-2.ssvBTS27-1100C-10Cmin-2.ssvBTS27-1100Cmin-5Cmin-2.ssvBTS27-1100Cmin-15Cmin.ssvBTS27-1100Cmin-30Cmin-2.ssv

Date2011-12-022011-12-162011-12-052011-12-012011-12-02

IdentityBTS-27-1100-40C/min-2BTS-27-1100C-10Cmin-2BTS-27-1100C-5Cmin-2BTS-27-1100C-15CminBTS-27-1100C-30Cmin

SampleBTS27-1100C-40C/min-2BTS27-1100C-10Cmin-2BTS27-1100C-5Cmin-2BTS-27-1100C-15CminBTS27-1100C-30Cmin

Mass/...67.90061.82066.60067.50068.500

Segme...1/11/11/11/11/1


AtmosphereHe/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---He/60 / ---/--- / He : 20ml/min/---

Corr.002002002002002

600 700 800 900 1000 1100Temperature /°C

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

DSC /(uV/mg)



Peak: 939.2 °C

Peak: 959.5 °C

Peak: 970.2 °C

Peak: 997.5 °C

Peak: 1008.5 °C

[1][2][3][4][5]

exo

112<G<200µm G>850µm200<G<850µm25<G<112µm

10K/min 30K/min20K/min5K/min 40K/min

10K/min

30K/min

20K/min

5K/min

40K/min





FileBTS-9_112-200_5Cm.ssvBTS-9_25-112_10Cm.ssvBTS-9_25-112_20Cm.ssvBTS-9_25-112_30Cm.ssvBTS-9_25-112_40Cm.ssv

Date2012-09-192012-09-192012-09-192012-09-202012-09-17

IdentityBTS9- 112-200- 5CmBTS9- 25-112- 10CmBTS9- 25-112- 20CmBTS9- 25-112-30CmBTS9- 25-112 40Cm

SampleBTS9- 112-200- 5CmBTS9- 25-112- 10CmBTS9- 25-112- 20CmBTS9- 25-112-30CmBTS9- 25-112 40Cm

Mass/mg43.00052.70054.00057.50054.700

Segment1/11/11/11/11/1



Corr.002002002002002

600 700 800 900 1000 1100Temperature /°C

0.0

0.1

0.2

0.3

0.4

0.5

DSC /(uV/mg)


Inflection: 769.7 °CPeak: 908.9 °C

Peak: 907.5 °C

Peak: 921.4 °C

Peak: 923.5 °C

Peak: 940.4 °C

[1][2][3] [4][5]

exo


FileBTS-9_850_10Cm.ssvBTS-9_25-112_10Cm.ssvBTS-9_112-200_10Cm.ssvBTS-9_200-850_10Cm.ssv

Date2012-09-192012-09-192012-09-202012-09-17

IdentityBTS9- 850- 10CmBTS9- 25-112- 10CmBTS9- 112-200- 10CmBTS9- 200-850- 10Cm

SampleBTS9- 850- 10CmBTS9- 25-112- 10CmBTS9- 112-200- 10CmBTS9- 200-850- 10Cm

Mass/mg65.60052.70056.00056.400

Segment1/11/11/11/1



Corr.002002002002

700 750 800 850 900 950 1000 1050 1100 1150Temperature /°C

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

DSC /(uV/mg)



Peak: 907.5 °C Peak: 922.4 °C

Peak: 947.8 °C Peak: 970.2 °C

[1]

[2]

[3][4]

exo


FileBTS27-1100C-10Cmin.ssvBTS27-1100C-10Cmin-2.ssvBTS27-1140Cmin-10Cmin-4.ssvBTS27-1300Cmin-10Cmin-3.ssv

Date2011-12-162011-12-162011-12-142011-12-08

IdentityBTS-27-1100C-10CminBTS-27-1100C-10Cmin-2BTS-27-1140C-10Cmin-4BTS-27-1300C-10Cmin

SampleBTS27-1100C-10CminBTS27-1100C-10Cmin-2BTS-27-1140C-10Cmin-4BTS27-1300C-10Cmin

Mass/...61.87061.82050.93069.500

Segme...1/11/11/11/1



Co...002002002002

700 750 800 850 900 950 1000 1050 1100 1150Temperature /°C

-0.10

-0.05

0.00

0.05

0.10

DSC /(uV/mg)


Peak: 932.9 °C Peak: 959.5 °C

Peak: 993.3 °C

Peak: 1055.9 °C


[1][2][3]

[4]

exo

NoAPS

Cristallization mechanism – Effect of composition

APS

13

112<G<200µm G>850µm200<G<850µm25<G<112µm

25<G<112µm

10°C/min


FileBTS27-1100Cmin-40Cmin-2.ssvBTS27-1100C-10Cmin-2.ssvBTS27-1100Cmin-5Cmin-2.ssvBTS27-1100Cmin-15Cmin.ssvBTS27-1100Cmin-30Cmin-2.ssv

Date2011-12-022011-12-162011-12-052011-12-012011-12-02

IdentityBTS-27-1100-40C/min-2BTS-27-1100C-10Cmin-2BTS-27-1100C-5Cmin-2BTS-27-1100C-15CminBTS-27-1100C-30Cmin

SampleBTS27-1100C-40C/min-2BTS27-1100C-10Cmin-2BTS27-1100C-5Cmin-2BTS-27-1100C-15CminBTS27-1100C-30Cmin

Mass/...67.90061.82066.60067.50068.500

Segme...1/11/11/11/11/1



Corr.002002002002002

600 700 800 900 1000 1100Temperature /°C

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

DSC /(uV/mg)



Peak: 939.2 °C

Peak: 959.5 °C

Peak: 970.2 °C

Peak: 997.5 °C

Peak: 1008.5 °C

[1][2][3][4][5]

exo

112<G<200µm G>850µm200<G<850µm25<G<112µm

10K/min 30K/min20K/min5K/min 40K/min

10K/min

30K/min

20K/min

5K/min

40K/min




Determination of Avrami parameters

n (Ozawa’s method)

ln))1ln(ln( nx

14

Granulo [µm] Avrami parameter « n » FRES NoAPS APS

25<G<112 2,0±0,1 ~ 2

112<G<200 2,0±0,1 ~ 2

200<G<850 2,0±0,1 ~ 2

G>850 1,3±0,3 ~ 1

x= crystallized fractionn= Avrami’s parameter (growth dimension)m= Avrami’s parameter (growth direction)




Activation energy

Eact (Matusita’s method) cstRTmE

T p

act

p

n)ln( 2

15

= heating rate [K/min]n= Avrami’s parameter (growth dimension)Tp=Max crystallisation peakEact=activation energy [kJ/mol]m= Avrami’s parameter (growth direction)R= gas constant




Activation energy

Eact (Matusita’s method) cstRTmE

T p

act

p

n)ln( 2

15

= heating rate [K/min]n= Avrami’s parameter (growth dimension)Tp=Max crystallisation peakEact=activation energy [kJ/mol]m= Avrami’s parameter (growth direction)R= gas constant


Hijiya et al., “Effect of phase separation on crystallization of glasses in the BaO-TiO2-SiO2

system”, 2009





Morphological orientation:• Large scale: XRD• Small scale: EBSD (FEG – SEM) and ACOM (TEM)




Crystal morphologies – Final stage

It changes and becomes finer Finer crystallization should mean PL enhancement …

5 µm 5 µm

5 µm

SiO2 + APS

FRES NoAPS

APS

1000°C 72H

16




Crystal morphologies – Final stage

It changes and becomes finer Finer crystallization should mean PL enhancement …

5 µm 5 µm

5 µm

SiO2 + APS

FRES NoAPS

APS

1000°C 72H

16


More study on early and final stages



Longs treatments: fine microstructure with sometime the disappearance of APS

Role of APS if same final microstructure ???

APS crystal morphologies – Final stage

17

Surface: 950°C 24h Surface: 950°C 72h

[HIJ] – 1200°C 24H




Complex crystallization microstructures with surface crystallization Role of APS as nucleation site? a/a interfacial energy too low… Conditions to become homogeneously fine : dendrite fragmentation?

Energie interface

APS crystal morphologies – Early stage

18






Morphological orientation:• Large scale: XRD• Small scale: EBSD* (FEG – SEM) and ACOM** (TEM)

*Electron BackScattered Diffraction** Automated Crystallographic Orientation Mapping



APS role BaO-TiO2-SiO2 Results & Discussions Conclusions PerspectivesLi

n (C

ount

s)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

23000

24000

2-Theta - Scale

5 10 20 30 40 50 60 70

Orientation - XRD

)2.0()2.0(

211002

211002IIII

IO

19

Lin

(Cou

nts)

0

100

200

300

400

500

600

2-Theta - Scale

5 10 20 30 40 50 60 70

Lin

(Cou

nts)

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

2-Theta - Scale

5 10 20 30 40 50 60 70

FRES

NoAPS

APS: case 1

APS: case 2

211 002001 211

002

001

Lin

(Cou

nts)

0

100

200

300

400

500

2-Theta - Scale

5 10 20 30 40 50 60




Crystallographic orientation – EBSD and ACOM

20

FRES - ACOMNoAPS – EBSD APS - ACOM


15°



Mechanism: surface crystallization for APS and NoAPS

Microstructures: evidence of surface crystallization for APS and NoAPS• NoAPS: dendrites• APS

– Short treatments: complex microstructures, no clear crystallization from interfaces– Long treatments: single microstructure, sometimes without APS !

Morphological and crystallographic orientation• Often [002] oriented growth for APS• Amorphous droplets do not seem to have any influence

This systematic study shows that APS does not influence the crystallization mechanism

Possible explainations:• Amorphous/amorphous interfacial energy too low to promote

crystallization• Effect of viscosity through composition

21

Conclusions



Clarify APS’s role on morphology …

• By using compositions closer to the miscibilty gap boundary – avoid the « composition effect »

• By developing EBSD measurements on early and final crystallization for APS

• By finding mid-treatment to clarify the transformation into fine crystallization

Why amorphous phase separation disappears with fresnoite dendrites ?

22

Perspectives



Thank you for your attention

Any questions?

We acknowledge the financial support of FRIA.


Documents

Emilie Boulay , Céline Ragoen , Stéphane Godet