CERAMICS WRINGING

Abstract

The object of the present invention is an integrally bonded composite component, a method for the production thereof, and the use thereof. The invention particularly relates to integrally bonded transparent ceramic composite components, to a method for the production of such ceramic composite components, and to the use thereof.

Claims

1. A composite component created by a permanent bonding of two components, wherein at least one component is a technical ceramic, and wherein the components are bonded without using a bonding material.

2. The composite component according to claim 1, wherein the two components are integrally bonded to each other, forming a chemical reaction zone.

3. The composite component according to claim 1, wherein one of the components is a technical ceramic and the other component is selected from a ceramic, a second technical ceramic, a transparent material, a glass, preferably an alkali aluminum silicate glass, and particularly preferably an alkali aluminum silicate glass which is pretensioned by pressure in the layer near the surface, a hardened glass, or a plastic.

4. The composite component according to claim 1, wherein the technical ceramic has a polycrystalline structure.

5. The composite component according to claim 1, wherein the technical ceramic is a polycrystalline, transparent technical ceramic.

6. The composite component according to claim 1, wherein the technical ceramic is a polycrystalline, transparent technical ceramic, preferably Mg—Al spinel (MgAl.sub.2O.sub.4) or polycrystalline aluminum oxide (α-Al.sub.2O.sub.3).

7. The composite component according to claim 1, wherein it is transparent.

8. The composite component according to claim 1, wherein it is transparent and has an RIT >60%, preferably >70% and particularly preferably >75%, spot frequencies <10%, preferably <3% and particularly preferably <1%, and haze <10%, preferably 5% and most preferably <2%.

9. A method for producing a composite component according to claim 1, wherein two components, of which at least one component is a technical ceramic, are bonded without using a bonding material, by wringing.

10. The method according to claim 9, wherein two components, of which at least one component is a technical ceramic, are bonded without using a bonding material, by means of a joining pressure.

11. The method according to claim 9, wherein a bonding agent is applied to the surface of one or both components, and then the components are wrung via the bonding agent(s).

12. The method according to claim 1, wherein metals or metal oxides are used as the bonding agent.

13. The method according to claim 1, wherein the bonding agent is applied by means of coating methods, in particular PVD methods (e.g., sputtering, electron-beam evaporation, ion-assisted deposition), CVD methods, or sol-gel methods.

14. The method according to claim 1, wherein the bonding agent is applied in layer thicknesses of 1 nm to 10 μm.

15. The method according to claim 1, wherein Si and Ti, more preferably SiO.sub.2, TiO.sub.2 or ITO (indium tin oxide), which are transparent, are used as the bonding agent.

16. The method according to claim 1, wherein a surface silicatization is performed by means of flame pyrolysis deposition of a silicon precursor.

17. The method according to claim 1, wherein the surface is coated with SiO.sub.2 by burning monosilane (SiH.sub.4).

18. The method according to claim 1, wherein the surfaces of the components being wrung have an evenness of <10 μm, preferably of <1 μm, and particularly preferably of <100 nm.

19. The method according to claim 1, wherein the surfaces being joined are formed to precisely fit each other.

20. The method according to claim 1, wherein pressure and/or heat is applied after or during the joining process.

21. The method according to claim 1, wherein the applied pressures lie between atmospheric pressure and 2000 MPa.

22. The method according to claim 1, wherein pressure is applied in a hot isostatic press (HIP) by gas pressure (argon, nitrogen, air).

23. The method according to claim 1, wherein the temperature range for the joining process is between room temperature and temperatures which are below the melting/softening temperature of the component with the lower melting/softening temperature.

24. The method according to claim 1, wherein the pressure and/or temperature treatment can be performed by means of rapid sintering technology, such as the FAST method (Field Assisted Sintering Technology), to shorten the process time.

25. The method according to claim 1, wherein prior to the wringing of the components, the surfaces to be joined are cleaned.

26. The method according to claim 1, wherein prior to the wringing of the components, the surfaces to be joined are freed of interfering substances by plasma etching, chemical cleaning, heating in air, in vacuum or in an H.sub.2 atmosphere, or by ion beam etching.

27. The method according to claim 1, wherein the coefficients of thermal expansion (CTE) of the components being wrung are matched to each other.

28. The method according to claim 1, wherein the coefficients of thermal expansion (CTE) of the components being wrung are as similar as possible.

29. The method according to claim 1, wherein one component consists of a material with a higher CTE, so as to generate compressive stress in the other component.

30-31. (canceled)

32. A display comprising the composite component according to claim 1.

33. An oven or chimney window display comprising the composite component according to claim 1.

Description

EXAMPLE 1

[0074] Two square spinel tiles with polished (r.sub.a<20 nm, preferably r.sub.a<10 nm and more preferably r.sub.a<4 nm) surface are pretreated with chemical agents and plasma cleaning. In a clean room environment, the surfaces are brought into contact at room temperature, aligned, and tempered in a hot isostatic press using isostatic pressure of >500 bar, preferably >1000 bar and more preferably >1500 bar. The necessary temperatures are >1200° C., preferably >1350° C., and more preferably >1500° C. After the heat treatment, an integral bond has formed by diffusion processes which makes possible the transparent composite components with RIT values >75%.

EXAMPLE 2

[0075] An alkali aluminum silicate glass which can be pretensioned with pressure in the layer near the surface is wrung with a transparent spinel ceramic. The dimensions of the square samples are 10 mm×10 mm. The glass has a thickness of 1 mm, and the ceramic thickness is 500 μm. The evenness is <5 μm, and the roughness is less than 1 nm. Chamfered edges of both joining surfaces allow a precise alignment before the heat treatment. The joining surfaces are pre-cleaned. The spinel ceramic is provided with a thin SiO.sub.2 layer which is made hydrophilic by a treatment with chemical agents such as nitric acid and an aqueous NH.sub.4OH:H.sub.2O.sub.2 solution at elevated temperatures >80° C. After alignment of the samples, the temperature treatment is performed in a high vacuum oven at temperatures between 200 and 400° C. After the heat treatment, an integral bond has formed which makes possible the transparent composite components with RIT values >75%.

EXAMPLE 3

[0076] An alkali aluminum silicate glass, which can be pretensioned with pressure in the layer near the surface, is wrung with a transparent spinel ceramic. The dimensions of the square samples are 10 mm×10 mm. The glass has a thickness of 1 mm, and the ceramic thickness is about 200 μm. The evenness is <500 nm, and the roughness is less than 1 nm. Chamfered edges of both joining surfaces allow a precise alignment before the heat treatment. The joining surfaces are plasma cleaned, uncoated and hydrophilic. After alignment of the samples, the heat treatment is performed in a high-vacuum oven at temperatures between 200 and 400° C. After the heat treatment, an integral bond has formed which makes possible the transparent composite components with RIT values >75%.