DE1596855A1 - Compositions for making opaque glass-ceramics - Google Patents

Description

Compositions for making opaque

Glass ceramics Λ

The invention relates to compositions for producing opaque glass ceramic, often also as glass-crystal mixed bodies referred to, which by a heat treatment of the glass melted from the compositions objects, above the transformation temperature (toughness

<10

Poise) are obtained by a controlled crystallization and have thermal expansion coefficients between 75 and 9 χ 10 "" V ° 0 in the temperature range of 20-30O ⁰ C. These

Glass ceramics are made from glasses which are made of

At O ^fc

Order Β ₂ Ο ^ νΑϋ | θ, CaO, BaO, MgO, ZnO, P ₂ O ^ ₁ TiOg, ZrO ₂ and As ₂ O ₅ . P ₂ O ₅ , TiO ₂ and ZrO ₂ act as nucleating agents and serve to initiate and thus promote crystallization. As ₂ O, serves to refine the glass melts · The other components determine, through the respective mixing ratio, the crystal phases that separate out during the ceramization process and thus the properties of the glass ceramics created in this way.

Such glass ceramics are generally characterized by a higher mechanical strength, duroh higher temperatures in use and by higher or lower coefficients of thermal expansion than the original glasses and are

BATH ORIGINAL

009851/0564

for example described in the German patents 1 045 056, 1 159 H2 and the German interpretative document 1 090 397

Both high melting and processing temperatures were required for the production of these known glass ceramics. Furthermore, the transition temperatures were also very high.

Object of the present invention are compositions which use only relatively low temperatures are required for the manufacture of opaque, mainly ^ -Bukryptitmischkristalle, zinc spinel and Celaian-containing glass-ceramics by heat treatment between 720 ⁰ C and 820 ⁰ O, the melted from the compositions glass articles BTI.

This object is achieved according to the invention by the following composition ranges in weight percent:

SiO ₂ 54 .0 - 62.0 B ₂ O ₃ 0 - 6.4 Al ₂ O ₃ 14th , 5 - 22.0 Ii ₂ O 1 , 5 - 2.8 CaO 0 - 1.9 BaO 0 - 7.0 MgO 0 - 7.5 ZnO * 0 - 12.0 P ₂ O ₅ 0 - 8.0 TiO ₂ 0 , 6 - 1.8 ZrO ₂ 1 ,8th - 4.0 Ae ₂ O ₃ 0 , 15- 0.30

whereby the following sums are to be observed

CaO + BaO + MgO + ZnO = _{7.5-19% by weight # P 2} O ₅ + TiO ₂ + ZrO ₂ = 3.6-11.6% by weight.

BATH ORIGINAL

009851/0564

159685S

The glass ceramics according to the invention are distinguished from the known glass ceramics by other compositions with a significantly higher content of the divalent metal oxides OaOi, BaO, MgO, ZnO and by a low content of Li ₂ O and SiO _2. The glasses are of good quality and leave between 156o and 1580 ⁰ O ⁰ C to melt in contrast to the known glass ceramics at lower temperatures process, "she eil in schmelzflUstigen state are less tough. Another difference is the crystalline phase content after conversion (ceramization). While the previous "LigO-containing opaque glass ceramics" were predominantly the lithium minerals ^ -sucryptite (U ₂ O t Al ₂ O ₃ 1 SiO ₂ - 1 1 1 ι 2) and h-Spoduaen (Li ₂ O 1 Al ₂ O ₃ t SiO ₂ «1 1 1 1 4) contained as a crystalline phase, in addition to / ^ - eucryptite mixed crystals, zinc pinell (SnO · Al ₂ O ₃ ) and Oelsian (BaO · Al ₂ O ₃ * 2SiO ₂ ) are often present as critical phases in the glass ceramics according to the invention. as a particular advantage, finally, the deep Umwandlungetemperatur "wipe 72o is to address ⁰ C and 820 ⁰ C, whereby deformation of the molded article is avoided during Keramieierung. laughing the prior art had so far Dafur temperatures are used to 1JOO ⁰ C, where for all known on the market product i-products dl "Endstuf · conversion over 100O ⁰ C.

In table 1 a 4 for further clarification of the finding the ZuaeaBenaetsumfea listed by 17 Olaakeramikgrtindgltsera. Table 2 MtIuUt vereefciedeae llfmchaftmrte der Gläeer and eatsireo shirts, ceramic products, sauce seeds keep with the crystalline phenomena.

BATH ORIGINAL

009851/0564

Table 1

% By weight compositions of the glass ceramic base glasses users 1-17.

No. SiO ₂ B ₂ O ₅ Al ₂ O ₃ Li ₂ O ι
^; Ba0 GaO
I. 1.90 7.0 3.0 ZnO XiO ₂ ZrO ₂ P ₂ O, , S ₂ O ₃ I - ·
' 1 54.0 6.4 17.0 2.8 .4.2 12.0 1.8 1.8 0.15 2 54 * 0 0.6 17.0 2.0 4.0 7.5 12.0 0.6 4.0 2.8 0.30 ι
3 54.0 • 0.6 17.0 . 2.8 7.0 7.5 12, c 1.0 3.6 2.0 0.30 4th 54.7 1.1 22.0 2.8 3.0 1.8 1.8 8.0 0.30 5 54.7 22.0 2.0 7.5 1.9 1.8 1.8 8.0 0.30 6th 60.5 14.5 2.0 3.0 12.0 1.0 2.8 4.2 0.30 7th 54.7 22.0 2.8 3.0 1.1 1.8 1.8 8.0 0.30 8th 62.0 14.5 1.5 12.0 1.0 1," 4.2 0.30 9 61.5 14.5 2.0 3.0 12.0 1.0 1.8 4.2 0.30 10 54.0 3.6 17.0 2.8 7.0 12.0 1.0 2.6 0.15 11th 61.0 16.0 2.5 3.0 12.0 1.8 1.8 0.30 12th 55.6 17.0 2.8 12.0 1.0 2.6 2.0 0.15 13th 61.0 14.5 ■ '2.5 12.0 1.0 1.8 4.2 Q, 30

14th ι 56 , 9 0.6 17th , ο; 1 , 5 '7 , 0 12.0 1 , 0 2.6 2.0 0 , 15 15th • 54 .0 17th , 0, 2 »0 _S 7 , 0. 12.0 0 , 6 4.0 2.8 0 , 30 16 L. 61 • 0 16 .ο! 2 , 5 3.0 12.0; 1 , 0 1.8 2.7 0 , 30 17th 54 .0 17th .0 2 .8th 7th , 0 12, Oj 1 .0 2.6 3.6

BATH ORIGINAL

009861/0564

copy

Tabel

Properties of the composition table 1-17 τοη Table ¹ / in the glassy and corrugated state after heat treatment τοη 2 hours 72O ⁰ C + 3 hours 820 ⁰ O.

! . Glass

¹ JLUBd. Τ _σ ( ⁰ C)

No. lKoeffiz.

1 (20-300 °)

j lights ktramiaiertee product

Au ad. Coefficient <Xx10 ⁷ (20-300 °)

Diohte (g / oom)

Proc. Density change

crystalline phases

42

600

2.67

75 2.88

7.87

A-Eucryptl solid solution, zincapinell, ZrO ₂ -KeImj phase

37

634

2.72

75 . 2.82 3.68

Quartz, zinc spinel, Celaian, ZrO ₂ seed phase

43

607

2.77

67 2.86 3.25

A-mixed eucryptite ; crystals, Celsian ,! ZOKIh j

41

670

2.48 j 29 2.53 2.02

Ä-Eucryptitmiech-

'Krietalle,

- ZrO ₂ seed phase

37

683

2.50

24 2.58: 3.20

! yÄ-Eucryptite-

'' krietalle,

! ZrOp germ phase

i 629

2.62

24 2.73 4.20

^{Lue-Eukryptitmigch-:;} Crystals, zinc-> splnell, ZrO ₂ -KeIm-: phase!

41

666

2.50

2.55 2.00

> A-Eukry ρ ti tmi a ch-'crystals,
ZrOg germ phaae

33

650

2.60

2.69 3.46

A-Eucryptitmiaoh- 'krifltalle, ZrO ₂ -Keimphaae

009851 / 056A

ORIGINAL

Continuation of τοη table 2

GIa β

Auad. ίΤ _κ ( ⁰ G)

No. Koeff ^ z. U ^ _1n I 3.5,

(20-300 °) i ceramized product

density ι Auad. density iProz. crystalline (g / ccm) ! Coefficient (g / ocm) -Density- Phases • ° t x10 ' country i (20-300 °) irration

- ,.

2.69 ι 3 »06 ι A-Eukryptitmiach- '' crystals, zinc-. I spinel, ZrO ₂ - j seed phase

: 35

628

2.61

18th

10

2.47

16 2.86 ί 4.39 i / Ä-Eukryptitmiach-l: crystals,

; . Celsian, ZinkapinelÜ

39

634

2.66 j 2.74 ■ 3.02

I yÄ-eucryptite miach- ¹ 'crystals, zinc pinel

! 45

637

2.76

13 ι 2.83 j 2.54

Ji-Kukryptitniiach-ZrOp-Ke iiaphaae

37

634

2.60! 2.67! 2.69

S Jj-eucryptite miach-; ^ crystals

14th

36

662

2.75. j 2.83! 2.90

'if-Eukryptitmiach-

i ^ tristalles,

• ZrOp germinal phases

'40

630

2.78 i 2 »84 ' 2.16

Eukry pt i traia ch-; crystals,
: ZrO ₂ -Ke imphase

16

37

!

2.62

10

1 »92 i Λ-EukryptitmiachjMcriatalle, Zinkj spineil, ZrO ₂ - i KeimphaBe ".

17th

39

627

2.75

1.82

i yA-eucryptite mix / krietalle,

Celaian, ZrO ₂ -

Germination phase

009851 / 056A copy

Claims (1)

- ν - Claim t Compositions for the manufacture of opaque, predominantly / L-Eukryptitmischkristalle, zinc spinel and Oelsian containing glass-ceramics by heat treatment between 72o C and ⁰ 820 ⁰ G, the molten compositions from the glass articles, characterized in duroh folgenden.Bereich SiO ₂ 54.0 - 62.0 B ₂ O ₅ O - 6.4 Al ₂ O ₃ 14.5 - 22.0 Li ₂ O 1.5 - 2.8 CaO 0 1.9 BaO 0 7.0 MgO 0 7.5 ZnO O 12.0 p ₂ o ₅ O 8.0 TiO ₂ 0.6 - 1.8 ZrO ₂ 1.8 - 4.0 Ae ₂ O ₃ 0.15- 0.30 whereby the following sums are to be observed: OaO -ι- BaO + MgO + ZnO - 7.5 - 19 wt .- *
PgOc "+ TiO ₂ + ZrO ₂ * 3.6 - 11.6 009851/0564 bath