Method for producing a ceramizable green glass component, and ceramizable green glass component, and glass ceramic article

Abstract

A method for producing ceramizable green glass components provided, as well as apparatus for performing such method and ceramizable green glass components producible by such method. The method is a redrawing process in which a preform is heated, in a deformation zone, to a temperature that enables redrawing of the glass. The deformation zone is particularly small, which permits redrawing of the ceramizable green glass bodies while avoiding ceramization during the redrawing. The method provides plate-like or sheet-like green glass components that have a particularly smooth surface.

Claims

1. A method for producing a glass ceramic article, comprising the steps of: preparing a glass melt of ceramizable glass; producing, from the glass melt, a ceramizable green glass body as a preform; providing the preform to a redrawing apparatus; heating at least a portion of the preform; redrawing the preform into a ceramizable green glass component, wherein the ceramizable green glass component has a crystalline content of less than 20 vol%.

2. The method as claimed in claim 1, wherein the crystalline content is less than 10 vol%.

3. The method as claimed in claim 1, wherein the ceramizable green glass component has a crystalline content of less than 2.5 vol%.

4. The method as claimed in claim 1, wherein the preform has a thickness D, a width B, and a length L, and wherein the green glass component has a thickness d, a width b, and a length l, and wherein a width-to-thickness ratio changes due to the redrawing.

5. The method as claimed in claim 4, wherein the redrawing develops a deformation zone that has a height H of not more than 50*D, the deformation zone being a portion of the preform having a thickness between 0.95*D and 1.05*d.

6. The method as claimed in claim 5, wherein the height H is not more than 6*D.

7. The method as claimed in claim 5, wherein the step of heating further comprises: heating the preform to a first temperature below a crystallization temperature and below a softening point of the green glass; and heating the preform to a second temperature above the softening point in the deformation zone.

8. The method as claimed in claim 1, wherein the ceramizable glass is selected from the group consisting of barium titanate glass, lithium aluminum silicate glass, lithium silicate glass, magnesium aluminosilicate glass, zinc aluminosilicate glass, magnesium silicate glass, sodium aluminosilicate glass, potassium aluminosilicate glass, phosphate glass, and calcium aluminosilicate glass.

9. The method as claimed in claim 1, wherein the ceramizable glass comprises a composition, in mol%: SiO.sub.2 5-20; Al.sub.2O.sub.3 4-15; B.sub.2O.sub.3 0-5; BaO 20-45; TiO.sub.2 20-60; CaO 0-5; SrO 0-10; CeO.sub.2 0-5; ZrO.sub.2 0-10; La.sub.2O.sub.3 0-40; MnO.sub.2 0-5; Y.sub.2O.sub.3 0-5; and Nb.sub.2O.sub.3 0-30.

10. The method as claimed in claim 1, wherein the ceramizable glass comprises a composition, in mol%: Al.sub.2O.sub.3 3-12; BaO 30-45; B.sub.2O.sub.3 0-5; La.sub.2O.sub.3 0-5; CeO.sub.2 0-5; SiO.sub.2 5-25; TiO.sub.2 25-42; CaO 0-5; Al.sub.2O.sub.3+B.sub.2O.sub.3+SiO.sub.2+P.sub.2O.sub.5 15-30; TiO.sub.2+ZrO.sub.2+Nb.sub.2O.sub.3+V.sub.2O.sub.5+HfO.sub.2+Sc.sub.2O.sub.3 20-50; and BaO+CaO+SrO+CeO.sub.2+RE.sub.2O.sub.3 30-50.

11. The method as claimed in claim 1, wherein the ceramizable glass comprises a composition, in mol%: Al.sub.2O.sub.3 5-15; BaO 20-30; La.sub.2O.sub.3 0-10; CeO.sub.2 0-2; SiO.sub.2 5-20; TiO.sub.2 40-60; ZrO.sub.2 5-10; Al.sub.2O.sub.3+B.sub.2O.sub.3+SiO.sub.2+P.sub.2O.sub.5 15-30; TiO.sub.2+ZrO.sub.2+Nb.sub.2O.sub.3+V.sub.2O.sub.5+HfO.sub.2+Sc.sub.2O.sub.3 30-55; and BaO+CaO+SrO+CeO.sub.2+RE.sub.2O.sub.3 25-40, wherein RE is one or more rare earth elements having atomic numbers selected from the group consisting of 39 and from 57 to 71.

12. The method as claimed in claim 1, wherein the ceramizable glass comprises the following components, in % of cations: TABLE-US-00005 Si.sup.4+ 45 to 65; Crystal agonists Li.sup.+ 25 to 40; K.sup.+ 0 to 8; Na.sup.+ 0 to 8; Crystal antagonists B.sup.3+ 0 to 5; Al.sup.3+ 0 to 10; Zn.sup.2+ 0 to 4; Nucleating agents Ce.sup.3+/Ce.sup.4+ >0 to 0.3; and Ag.sup.+ >0 to 0.5.

13. The method as claimed in claim 1, wherein the ceramizable green glass component comprises a thickness d of less than 2000 m.

14. The method as claimed in claim 1, wherein the ceramizable green glass component comprises a thickness d of less than less than 10 m.

15. The method as claimed in claim 1, wherein the ceramizable green glass component comprises a thickness-to-width ratio d/b of not more than 1:200.

16. The method as claimed in claim 1, wherein the ceramizable green glass component comprises a thickness-to-width ratio d/b of not more than 1:200,000.

17. The method as claimed in claim 1, wherein the ceramizable green glass component comprises a surface having at least one section with a fire-polished surface quality of R.sub.a 20 nm.

18. The method of claim 17, further comprising configuring the ceramizable green glass component to a shape with two faces and a peripheral edge, and wherein the surface having the at least one section with the fire-polished surface is at least one of the two faces.

19. The method of claim 1, further comprising subjecting the ceramizable green glass component to a ceramization process, with or without intermediate processing, after having been cooled to less than 300 C., wherein during the ceramization process the ceramizable green glass component is reheated and ceramized to produce the glass ceramic article.

20. The method of claim 19, wherein the ceramization process provides the glass ceramic article with a crystalline content of at least 20 vol%.

21. The method of claim 19, wherein the ceramization process provides the glass ceramic article with a crystalline content of at least 90 vol%.

22. The method of claim 19, further comprising configuring the glass ceramic article for a use selected from the group consisting of a dielectric component in a capacitor, an antenna, an interposer in an electronic component, a separator in a battery, a substrate for a thin film battery, a flexible substrate for a display, a mask or filter for a display, a substrate for a high-temperature deposition processes, a cover or protection for an optical component, a cover or protection for an electronic component, and an electronic substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic side view of the configuration of an exemplary embodiment of a redrawing apparatus according to the invention;

(2) FIG. 2 schematically shows the procedure of a method according to the prior art;

(3) FIG. 3 schematically shows a preform;

(4) FIG. 4 schematically illustrates a configuration comprising a laser;

(5) FIG. 5 schematically shows the operation of an optional radiation heater as a heating means;

(6) FIG. 6 illustrates the influence of the height of the deformation zone during redrawing;

(7) FIG. 7 shows a possible thickness distribution;

(8) FIG. 8 shows an example of the average width b (gross width) of a redrawn green glass component and the required drawing force, as a function of the viscosity of the glass of the preform in each case; and

(9) FIG. 9 shows an example of the ratio of the average width b (gross width) to the average thickness d (net thickness) of the redrawn glass component and the required drawing force, as a function of the viscosity of the glass of the preform in the deformation zone in each case.

DETAILED DESCRIPTION

(10) In the following detailed description of preferred embodiments, the same reference numerals designate substantially similar parts in or on these embodiments, for the sake of clarity.

(11) FIG. 1 is a schematic side view of the configuration of an exemplary embodiment of a redrawing apparatus according to the invention. In the redrawing apparatus, a preform 1 is advanced through the device from above downwards. The redrawing apparatus comprises two heating means 2 which are arranged in a central region of the device. In this embodiment, the heating means are shielded by shields 3 so that a deformation region 4 is defined. A portion of the preform 1, which is located in the deformation region 4 is heated so that it reaches temperature T2. This portion is the deformation zone 5 having a height H. The preform 1 is drawn downwards by drawing means 6, here implemented in the form of two driven rollers. Since the feeding means 7, here likewise implemented in the form of rollers, feed the preform 1 slower than the drawing means 6 draw, the preform 1 is deformed in deformation region 4. Thereby, preform 1 becomes thinner, that means the thickness d after deformation is smaller than the thickness D before deformation.

(12) Before the preform 1 is fed into the deformation region 4, it is preheated to a temperature T1 using preheating means 8, here symbolized by a burner flame. After having passed through the deformation region 4, the preform 1 is exposed to cooling means 9, here symbolized by an ice crystal.

(13) FIG. 2 schematically shows the procedure of a method according to the prior art. This view differs from that of FIG. 1 in that it illustrates the change in width B of the preform. Preform 1 is advanced into a deformation region 4. Deformation region 4 is heated by heating means 2, here a resistance heater. Preform 1 is heated so that a deformation zone 5 develops in the glass, in which the glass has a low viscosity. However, since limits are lacking and because of the height of the heating means 2, the deformation zone 4 is substantially larger than that of the present invention. Therefore, the reduction in width of the preform 1 is particularly pronounced. Furthermore, drawing means 6 are shown, which extend the preform 1 longitudinally.

(14) FIG. 3 schematically shows a preform having a length L, a thickness D, and a width B.

(15) FIG. 4 schematically shows the configuration of a heating means comprising a laser 10. The laser beam is directed onto the ceramizable green glass using a scanner mirror 11. By moving the scanner mirror, the deformation zone is uniformly heated. An optional optical beam forming system is not shown.

(16) FIG. 5 schematically illustrates the operation of a possible radiation heater which may be employed as a heating means 2. Depending on its distance from preform 1, the height of deformation zone 5 will be different. The figure moreover shows how the deformation zone 5 can be limited by being shaded using a shield 3, in order to obtain a deformation zone 5 of rather small height.

(17) Thus, both the distance and the configuration of the heater may serve to adjust the height of deformation zone 5.

(18) FIG. 6 shows how the width of a glass product depends on the height of the deformation zone during redrawing. It can be seen that a deformation zone of smaller height has the effect to reduce the reduction in width of the preform.

(19) FIG. 7 shows the profile of thickness d of a flat glass product according to example 3 over the width b of the product. As is apparent therefrom, the borders at the edges of the glass product are rather narrow. The portion having a homogeneous low thickness can be used for the application of the glass product, the borders have to be severed. With the inventive method, yield is particularly high.

(20) FIG. 8 shows an example of the average width b (gross width) of the extended green glass component and the drawing force required for extending, as a function of the viscosity of the glass of the preform, for the case of a preform having a thickness of 4 mm and a width of 400 mm, which is introduced at 5 mm/min into a muffle having a height of 40 mm. The glass is withdrawn at 200 mm/min. It is clearly apparent that the required drawing force progressively increases with increasing viscosity. Furthermore, it can be seen that the average width b of the obtained product progressively decreases with increasing viscosity.

(21) FIG. 9 shows an example of the ratio of the average width b (gross width) to the average thickness d (net thickness) of the extended glass component and the drawing force required for extending, as a function of the viscosity of the glass of the preform in the deformation zone, for the case of a preform having a thickness of 4 mm and a width of 400 mm, which is introduced at 5 mm/min into a muffle having a height of 40 mm. The glass is withdrawn at 200 mm/min. It is apparent that the width-to-thickness ratio b/d of the obtained product progressively decreases with increasing viscosity. When compared to the decrease in average width b with increasing viscosity as shown in FIG. 7, the ratio b/d decreases even more strongly with increasing viscosity.

(22) The table below shows, by way of example, a redrawing method which may be carried out as described in U.S. Pat. No. 3,635,687, for example, with a first example 1 without edge cooling and a second example 2 with edge cooling.

(23) These prior art examples are compared to a third example 3, the inventive method, which uses a very small deformation region. The length of the deformation region in this case is less than one tenth of the length of the deformation region in a prior art method according to any one of the first two examples.

(24) TABLE-US-00004 TABLE 1 Exemplary embodiment and comparative examples Example 1: Example 2: U.S. Pat. U.S. Pat. No. No. 3,635,687 3,635,687 without edge with edge Example 3: cooling cooling Invention Length of deformation 508 508 30 region [mm] Width B [mm] of preform 508.0 508.0 120.0 Thickness D [mm] of preform 6.4 6.4 14.0 Ratio B/D 80.0 80.0 8.6 Width b [mm] of component 19.1 61.4 100.0 Central thickness d [mm] of 0.1 0.1 0.3 component Ratio b/d 250.0 853.3 333.3 (Ratio b/d)/(Ratio B/D) 3.1 10.7 38.9

(25) The inventive method permits to produce ceramizable green glass components, which are characterized by: a thickness d of less than 2000 m, less than 1000 m, less than 500 m, less than 100 m, preferably less than 50 m, more preferably less than 40 m, less than 30 m, less than 20 m, less than 10 m; and/or a thickness-to-width ratio d/b of the green glass component of not more than 1:200, preferably not more than 1:20,000, and most preferably not more than 1:200,000; and/or at least one surface having fire-polished surface quality with R.sub.a 20 nm, at least in sections thereof.

(26) A ceramizable green glass component produced in this manner is furthermore characterized by the fact that the ceramizable green glass component has a crystalline content of less than 20 vol %, preferably less than 10 vol %, and more preferably less than 5 vol % and can consequently be ceramized in a conventional ceramization process.

(27) The ceramizable green glass component may be plate-shaped so as to have two opposite faces and a peripheral edge.

(28) At least one of the faces may have a fire-polished surface quality with R.sub.a 20 nm, at least in sections thereof.

(29) The ceramizable green glass component may further have a thickness-to-width ratio d/b of not more than 1:200 to 1:20,000, preferably of at most 1:20,000, more preferably of at most 1:200.000.

(30) The ceramizable green glass component may be subjected to a ceramization process, with or without intermediate processing, in order to produce a glass ceramic article. In this case, after having been cooled to less than 300 C., preferably to room temperature, the ceramizable green glass component can be reheated and ceramized.

(31) After ceramization, the glass ceramic article may have a crystalline content of at least 20 vol %, preferably at least 50 vol %, and more preferably at least 90 vol %.

(32) A glass ceramic article produced in this manner can be used as a dielectric component in capacitors, as an antenna, as an interposer in electronic components, as a separator in batteries, as a substrate for thin-film batteries, as a flexible substrate for displays, as a mask or filter for display applications, as a substrate for high-temperature deposition processes, for example crystal growth, as a cover or protection for optical or electronic components, or as an electronic substrate.

LIST OF REFERENCE NUMERALS

(33) 1 Preform 2 Heating means 3 Shield 4 Deformation region 5 Deformation zone 6 Drawing means 7 Feeding means 8 Preheating means 9 Cooling means 10 Laser 11 Scanner mirror