New High Zirconia fused cast material for high

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New High Zirconia fused cast material for high quality glass without low temperature oxygen

New High Zirconia fused cast material for high quality glass without low temperature oxygen blistering ICF Technical meeting, Sienna November 05 th , 2007

New High Zirconia fused cast material for high quality Glass without low temperature oxygen

New High Zirconia fused cast material for high quality Glass without low temperature oxygen blistering Topics of the presentation Ø Main interest of HZFC material in high quality glass Ø Low temperature oxygen blistering phenomenon Ø Hypothesis of mechanism with HZFC Ø How to prevent oxygen blistering Ø Properties of new HZFC Ø Influence of crystal glass composition evolution regarding AZS and HZFC materials

Interest of HZFC in quality glass 1

Interest of HZFC in quality glass 1

High Zirconia Fused Cast Microstructure Typical composition Al 2 O 3: 0. 4 -

High Zirconia Fused Cast Microstructure Typical composition Al 2 O 3: 0. 4 - 2 % Zr. O 2 > 90 % Si. O 2: 3 - 7 % Na 2 O: 0 – 0. 4 % B 2 O 3: 0 – 1 % Zirconia microprobe mapping Al 2 O 3 Si. O 2 Glassy phase Na 2 O 100 µm Zr. O 2

Fused Cast AZS Microstructure Typical composition Al 2 O 3: 46 % Zr. O

Fused Cast AZS Microstructure Typical composition Al 2 O 3: 46 % Zr. O 2: 41% Si. O 2: 12 % Na 2 O: 1% Zirconia microprobe mapping Al 2 O 3 Zr. O 2 Glassy phase Corundum / Zirconia eutectic Si. O 2 Na 2 O

Main interest of using HZFC material Low level of glass contact defects Ø low

Main interest of using HZFC material Low level of glass contact defects Ø low level of Crystallized or vitreous defect HZFC origin of defects in convective area as : AZS (41% Zr. O 2) 10% Al 203, 2% Zr. O 2, 11% Pb. O, 16%K 2 O, 0. 8% Na 2 O Leucite (Al 203 -K 2 O-4 Si. O 2) with zirconia nodule Glass contact AZS interface, primary Zr. O 2 Clear Knot

Main interest of using HZFC material Low level of glass contact defects Ø low

Main interest of using HZFC material Low level of glass contact defects Ø low level of blistering at high temperature Test condition : TV/PDP glass, Temperature : 1450°C, Duration : 70 H Crucible test HZFC AZS (41% Zr. O 2)

Low temperature oxygen blistering phenomenon 2

Low temperature oxygen blistering phenomenon 2

low temperature oxygen blistering phenomenon High quality glass extended use of HZFC materials in

low temperature oxygen blistering phenomenon High quality glass extended use of HZFC materials in the furnace final part (fining, feeder, …) ü To solve some corrosion problem (borosilicate, crystal glass …. . ) ü To prevent Glass contact defect related to chemical composition of the glass (compare alpha/béta alumina product, or AZS product ) Glass Si. O 2 Na 2 O K 2 O Ca. O Wt % 58 -69 4– 5 5 - 10 1 – 8 5– 7 Ba 0 Sr. O Mg. O Al 2 O 3 5– 7 0– 2 Oxygen blistering phenomenon 1– 7 Zr. O 2 2– 4

Low temperature oxygen blistering phenomenon Ø Blistering phenomenon with high efficiency Blistering crucible test

Low temperature oxygen blistering phenomenon Ø Blistering phenomenon with high efficiency Blistering crucible test at 1120°C , 30 hours , alkali test glass Necessary conditions to obtain high oxygen blistering Ø Air outside crucible Ø Temperature < 1130°C Ø Alkalii inside the glass

Low temperature oxygen blistering consequences Electrical furnace HZ 1250°C • bubble defect in glass

Low temperature oxygen blistering consequences Electrical furnace HZ 1250°C • bubble defect in glass 1120°C cold area Glass glass • Corrosion enhancement by upward drilling phenomenon Oxygen blistering in the join ( low temperature area )

Hypothesis of this phenomenon 3

Hypothesis of this phenomenon 3

Low temperature oxygen blistering mechanism : Thermal expansion % High temperature dependence of this

Low temperature oxygen blistering mechanism : Thermal expansion % High temperature dependence of this phenomenon related to zirconia crystallographic transformation Monoclinic zirconia Quadratic zirconia Temperature 1120 -1140°C

Low temperature oxygen blistering mechanism : Conductivity process change with zirconia transformation Electrical conductivity

Low temperature oxygen blistering mechanism : Conductivity process change with zirconia transformation Electrical conductivity process change with temperature at the zirconia crystalographic transformation

Low temperature oxygen blistering mechanism : Arrhenius diagram : Log(sigma) = f(1/T) for zirconia

Low temperature oxygen blistering mechanism : Arrhenius diagram : Log(sigma) = f(1/T) for zirconia contribution 1/T(K°) 0 0 1 E-04 2 E-04 3 E-04 4 E-04 5 E-04 6 E-04 7 E-04 8 E-04 9 E-04 0, 001 0, 001 0, 002 -2 Ln sigma (ohm-1. cm-1) -4 -6 -8 ER 1195 Activation energy increase after zirconia transformation -10 -12 -14 ØElectronic to ionic conductivity change at the zirconia temperature transformation

Oxygen Blistering mechanism Hypothesis Refractory wall Oxydation 2 O 2 - O 2 +

Oxygen Blistering mechanism Hypothesis Refractory wall Oxydation 2 O 2 - O 2 + 4 e- glass M Y+ + x e- M y-x Na+, K+ réduction Reaction e- Electro chemical process that can take place because of: Ø alkali available in the glass Ø electronic conductivity in the refractory at T<1130°C Ø oxygen outside of the crucible that could be reduced (or that could reoxydized impurities)

How to prevent low temperature oxygen blistering with HZFC 4

How to prevent low temperature oxygen blistering with HZFC 4

How to prevent low temperature blistering in glass D e fo r m a

How to prevent low temperature blistering in glass D e fo r m a ti o n % Y 2 O 3 addition Monoclic zirconia Quadratic zirconia Temperature Glass crystallization temperature

How to prevent low temperature oxygen blistering Y 2 O 3 addition that allow

How to prevent low temperature oxygen blistering Y 2 O 3 addition that allow to : ü lower the electronic conductivity temperature area Ø Stay stable with temperature Ø Doesn’t react with alumina or silica inside the glassy phase Ø Form solid solution with zirconia Microprobe mapping of Y 2 O 3

Y 2 O 3 necessary level is related to glass crystallization curve (Higlh quality

Y 2 O 3 necessary level is related to glass crystallization curve (Higlh quality display panel glass ) Y 2 O 3 target = [ 0. 8 – 1%]

Sensible shift of zirconia transformation temperature with Y 2 O 3 addition Ø Need

Sensible shift of zirconia transformation temperature with Y 2 O 3 addition Ø Need to adapt the glassy phase composition to the lower reverse temperature transformation during the annealing process of the block

Glassy phase modification with Y 2 O 3 addition Glassy phase properties measurements in

Glassy phase modification with Y 2 O 3 addition Glassy phase properties measurements in the Si. O 2 -Al 2 O 3 -Na 2 O-Y 2 O 3 system simulation ü Thermal expansion ü Glass transition temperature, crystallization ü High température viscosity To design the right level of Si. O 2, Na 20 and Al 2 O 3 for a given Y 2 O 3 %

New HZFC materials : First industrial results Cut block Low level of internal defect

New HZFC materials : First industrial results Cut block Low level of internal defect Si. O 2 = 4 – 6 %, Al 2 O 3 = 0. 7 -1. 2 %, Na 2 O = 0. 4 - 0. 8%, Y 2 O 3 = 0. 8 – 1%

Blistering test results on industrial products : Crucible test : 1100°C , 30 hours

Blistering test results on industrial products : Crucible test : 1100°C , 30 hours HZFC Display panel glass High alkalii test glass New HZYFC Display panel glass High alkalii test glass No oxygen bubles with the new product at 1100°C

Blistering test results on industrial products : Crucible test : 1000°C , 30 hours

Blistering test results on industrial products : Crucible test : 1000°C , 30 hours HZFC Display panel glass High alkalii test glass New HZYFC Display panel glass High alkalii test glass ü No oxygen blistering up to 1000°C with new HZFC ü Secure solution with display panel glass (no blistering up to crystallization temperature)

Glass contact properties 5

Glass contact properties 5

Static corrosion test (T-test) HZFC stone New HZFC 1 -2 1 -2 0 0

Static corrosion test (T-test) HZFC stone New HZFC 1 -2 1 -2 0 0 -1 1 1 (droplet ) Stone (crucible) Indice global Conditions of the test : Temperature : 1500°C Duration : 48 heures Glass : PDP

Dynamic corrosion test (test MGR) HZFC Indice 100 New HZFC 105 83 Conditions d’essais

Dynamic corrosion test (test MGR) HZFC Indice 100 New HZFC 105 83 Conditions d’essais : Température : 1500°C Duration : 48 heures Glass : PDP 88

Influence of crystal glass composition evolution regarding AZS and HZFC materials 6

Influence of crystal glass composition evolution regarding AZS and HZFC materials 6

Crystal glass composition evolution Evolution to lead free Glass Typical Pb. O Crystal Glass

Crystal glass composition evolution Evolution to lead free Glass Typical Pb. O Crystal Glass Lead free Glass (Ba. O) Lead free Glass (w/o Ba. O) Na 2 O 3 -5 7, 5 -11 8, 6 -10, 9 K 2 O 10 -14 5 -7 8, 7 -10 5, 9 -8, 9 Ba. O Al 2 O 3 <0, 05 0, 4 -3, 4 1 -2 Zn. O 0 -2 0, 9 -2, 3 -5, 5 Pb. O 25 -32 Ca. O 2 -6 4 -6 Ti. O 2 <0, 05 1 -1, 7 Si. O 2 in complement First family : lead free glass with Ba. O addition, ( increase of Al 2 O 3, Ca. O, Na 2 O, decrease of K 2 O ) Second family: lead free glass without Ba. O, with main addition of Zn. O, Ti. O 2

Glass evolution impact of refractory corrosion Not working at iso viscosity Tests conditions :

Glass evolution impact of refractory corrosion Not working at iso viscosity Tests conditions : Diameter: 22 mm, height: 100 mm Speed: 6 rpm Temperature: 1450°C, duration 72 hours HZFC Corroded Volume (cm 3) Crystal Glass AZS (41% Zr. O 2) Index Corroded Volume (cm 3) Index 2, 62 53 1, 41 100 Lead free Glass (Ba. O), 3. 85 79 3. 09 100 Lead free Glass (W/o Ba. O) 4, 53 63 2, 88 100 Ø Corrosion level increase with lead free crystal glass Ø Corrosion level with Crystal lead free glass with/without Ba. O are similar Ø Lower corrosion resistance of HZFC compared to AZS material (protective interface layer) in condition of high glass interface removal : this is not the case with horizontal interface like in paving or electrode block due to heavy enriched zirconia interface SAMSUNG CORNING 04/98

Glass evolution impact of refractory stoning potential Tests conditions Temperature: 1450°C Time: 48 hours

Glass evolution impact of refractory stoning potential Tests conditions Temperature: 1450°C Time: 48 hours HZFC AZS Lead crystals HZFC AZS (41% Zr. O 2) HZFC Index 0 1 -2 Lead free (Ba. O) HZFC AZS (41% Zr. O 2) Index given from 1 to 5 (1: no stone in drop, 5: lot of crystals in drop) AZS Index 0 0 - 1

HZFC – glass interface Lead Crystal glass Lead free Crystal glass 200µ m No

HZFC – glass interface Lead Crystal glass Lead free Crystal glass 200µ m No formation of HZFC/Crystal glass interface in each case

AZS – glass interface Lead Crystal glass Lead free crystal glass 100µ m 200µ

AZS – glass interface Lead Crystal glass Lead free crystal glass 100µ m 200µ m -Dissolution of alumina from eutectic crystals -Free zirconia crystals

Glass defect coming from AZS material in lead free crystal glass Chemical composition of

Glass defect coming from AZS material in lead free crystal glass Chemical composition of glass defect % 1 2 3 4 Na 2 O 9. 9 10. 3 10. 4 K 2 O 3. 9 3. 8 4. 0 Mg. O 0. 05 0. 03 0. 04 0. 05 Al 2 O 3 13. 4 13. 6 13. 7 13. 6 Ca. O 5. 3 4. 9 Zn. O 0. 8 0. 7 Zr. O 2 6. 7 6. 6 6. 4 Ba. O 4. 9 5. 2 4. 8 4. 7 Ti. O 2 0. 03 0. 08 0. 03 0. 04 SO 3 - -

As a conclusion Ø Glass composition change towards lead free glass Ø Enhance corrosion

As a conclusion Ø Glass composition change towards lead free glass Ø Enhance corrosion level Ø Doesn’t affect the advantage of using HZFC in terms of defect due to very sharp glass refractory interface Ø New HZFC solution to avoid low temperature oxygen blistering by modifying Zr. O 2 electrical properties üLess glass defects at low temperature (oxygen blisters) ü Better corrosion resistance without upward drilling phenomenon in join (low temperature area ) üBetter filling of the block ü Same advantage as conventional HZFC product