Protective layer for a body, and process and arrangement for producing protective layers

• US 20050084705A1
• Filed: 09/08/2004
• Published: 04/21/2005
• Est. Priority Date: 09/13/2003
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Dzick, Jurgen, Klippe, Lutz, Krause, Cora
• Granted Patent: US 7,541,102 B2
• Time in Patent Office: Days
• US Class Current: 428/633
• CPC Class Codes: C03C 17/002 for flat glass, e.g. float glass
• CPC Class Codes: C03C 17/22 with other inorganic material C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 17/225 Nitrides
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 2217/22 ZrO2
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: C03C 2217/77 Coatings having a rough surface
• CPC Class Codes: C03C 2218/155 by reactive sputtering
• CPC Class Codes: C03C 2218/156 by magnetron sputtering
• CPC Class Codes: C03C 2218/322 Oxidation
• CPC Class Codes: C23C 14/3442 using an ion beam
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/1259 Oxide
• CPC Class Codes: Y10T 428/12618 Plural oxides
• CPC Class Codes: Y10T 428/12771 Transition metal-base component

Abstract

Many applications, in particular in the domestic sector, require bodies which have a protective layer with a high scratch resistance and thermal stability. One typical example is glass-ceramic cooking surfaces of modern cooking hobs.

The invention provides a corresponding protective layer which comprises at least one hard-material layer formed from a metal oxide and/or metal nitride and/or metal carbide and/or metal oxynitride and/or metal carbonitride and/or metal oxycarbonitride which has laterally closely cohesive, crystalline columns which grow perpendicular to the surface of the body and the lateral dimension of which is on average less than 1 μm, preferably less than 200 nm, and which predominantly has crystal orientations which, in the case of columnar growth, have little tendency to widen out, the surface roughness of the hard-material layer having an R_a value of less than 50 nm, preferably less than 20 nm.

Claims

1. A protective layer for a body, which comprises at least one hard-material layer formed from metal oxide and/or metal nitride and/or metal carbide and/or metal oxynitride and/or metal carbonitride and/or metal oxycarbonitride, wherein at least one hard-material layer comprising a metal oxide and/or metal nitride and/or metal carbide and/or metal oxynitride and/or metal carbonitride and/or metal oxycarbonitride has a morphologically dense column structure that grows substantially perpendicular to the surface of the body.

2. The protective layer as claimed in claim 1, wherein the dense column structure of the hard-material layer is at least 50%, preferably more than 80%, cry stalline.

3. The protective layer as claimed in claim 1 or 2, wherein the columns on average have a lateral dimension of less than 1 μ

m, and preferably of less than 200 nm.

4. The protective layer as claimed in one of claims 1 to 3, wherein the layer thickness of the hard-material layer is in the range from 100 to 20 000 nm, preferably between 500 and 10 000 nm, and particularly preferably between 1500 and 5000 nm.

5. The protective layer as claimed in one of claims 1 to 4, wherein the surface roughness has an R_a value of <

50 nm, preferably an R_a value of <

30 nm and particularly preferably an R_a value of <

20 nm.

6. The protective layer as claimed in one of claims 2 to 5, wherein the hard-material layer which has a dense crystalline column structure comprises silicon nitride.

7. The protective layer as claimed in one of claims 2 to 5, wherein the hard-material layer which has a dense crystalline column structure comprises a metal oxide in a temperature-stable crystal phase.

8. The protective layer as claimed in claim 7, wherein the hard-material layer comprises zirconium oxide in a temperature-stable crystal phase.

9. The protective layer as claimed in claim 8, wherein at least one further component is admixed to the zirconium oxide in order to stabilize the temperature-stable crystal phase.

10. The protective layer as claimed in claim 9, wherein the stabilizing component comprises at least one oxide selected from the group consisting of yttrium oxide, calcium oxide, magnesium oxide, tantalum oxide, niobium oxide, scandium oxide, titanium oxide or the lanthanoid oxide group, such as for example lanthanum oxide or cerium oxide.

11. The protective layer as claimed in one of claims 8 to 10, wherein the hard-material layer comprising zirconium oxide additionally contains the component hafnium oxide.

12. The protective layer as claimed in claim 10 or 11, wherein the hard-material layer comprising zirconium oxide contains, as stabilizing component, from 0.5 to 50 mol % of Y₂O₃, preferably from 1 to 10 mol % of Y₂O₃, and particularly preferably from 1.0 to 7.5 mol % of Y₂O₃.

13. The protective layer as claimed in claim 12, wherein the hard-material layer comprising zirconium oxide contains, as stabilizing component, 4 mol % (±

1 mol %) of Y₂O₃.

14. The protective layer as claimed in one of claims 1 to 13, which has a further hard-material layer, in particular a transparent hard-material layer.

15. The protective layer as claimed in claim 14, wherein at least 50% of the further hard-material layer is formed by silicon oxide.

17. The protective layer as claimed in one of claims 1 to 16, which is distinguished by its use for coating bodies made from glass, glass-ceramic or other non-metallic, crystalline materials.

18. A cooking hob, which has a coating which includes a layer as claimed in one of claims 1 to 16.

19. A cooking device, which has a coating which includes a layer as claimed in one of claims 1 to 16.

20. A process for coating a body with a protective layer, in particular with a protective layer as claimed in claims 1 to 17, comprising the steps of:

a) providing the body and the layer substances in a vacuum system,

b) coating the body by means of a reactive physical vapor deposition process, producing layer substances in atomic dimensions,

wherein

b1) during the reactive physical vapor deposition process the layer substances produced in atomic dimensions are additionally energy-enriched, so that morphologically dense column structures are formed during the layer growth.

21. A process for coating a body made from glass, glass-ceramic or another nonmetallic, crystalline material, in particular for coating a glass-ceramic hotplate, with a protective layer, in particular with a protective layer as claimed in claims 1 to 17, comprising the steps of:

a) providing the body and the layer substances in a vacuum system,

b) coating the body by means of a reactive physical vapor deposition process, producing layer substances in atomic dimensions

wherein

a1) the body which is to be coated, made from glass, glass-ceramic or another, nonmetallic, crystalline material, is transferred into the vacuum system in order to be coated immediately after it has been produced, and

b1) during the reactive physical vapor deposition process, the layer substances produced in atomic dimensions are additionally energy-enriched, so that morphologically dense column structures are formed during the layer growth.

22. The process as claimed in claim 20 or 21, wherein the body is coated by magnetron sputtering.

23. The process as claimed in claim 20 or 21, wherein the body is coated by ion beam sputtering.

24. The process as claimed in one of claims 20 to 23, wherein the additional energy enrichment is effected by means of an assisting ion beam, the ion beam being directed onto the substrate, and the atoms of the layer substances produced in atomic dimensions growing in morphologically dense column structures as a result of controlled setting of the intensity of the ion beam and selection of the energy of the ions.

25. The process as claimed in claim 24, wherein the energy of the ions of the assisting ion beam is between 1 and 2500 eV, preferably between 1 and 800 eV, and particularly preferably between 20 and 450 eV.

26. The process as claimed in claim 24 or 25, wherein an additional ion source provides the ions of the assisting ion beam.

27. The process as claimed in claim 24 or 25, wherein the ions of the assisting ion beam are taken from the plasma involved in the sputtering process.

28. The process as claimed in one of claims 20 to 27, in particular for coating a body having a protective layer as claimed in claims 7 to 13, wherein the layer substances are in solid form, as metallic components or as metal oxides.

29. The process as claimed in claim 28, wherein oxygen is additionally fed into the vacuum system during the vapor deposition process.

30. The process as claimed in claim 28 or 29, wherein at least one additional gas, preferably oxygen, for optimizing the material-removal rate during the production of the layer substances and for optimizing the formation of atomic oxygen is fed into the vacuum system.

31. The process as claimed in one of claims 26 to 30, wherein the coating of the body comprises a thermal aftertreatment, preferably in an oxygen atmosphere, in order to optimize the crystal structure and the oxygen content of the applied layer substances.

32. The process as claimed in claim 31, wherein the thermal aftertreatment is carried out at temperatures of up to 800°

C., preferably at temperatures of between 400°

C. and 700°

C.

33. The process as claimed in one of claims 20, 22 to 32, wherein the surface of the body to be coated is subjected to a cleaning operation before it is coated.

34. The process as claimed in claim 33, wherein the cleaning is carried out in a vacuum chamber by plasma treatment with ions, the energy of which is preferably in the range from 1 to 2500 eV, with preference from 50 to 1600 eV, and particularly preferably from 100 to 500 eV.

35. The process as claimed in one of claims 20 to 34, wherein the surface of the body to be coated is activated before being coated.

36. The process as claimed in claim 35, wherein the activation is carried out in a vacuum chamber by means of a plasma treatment with ions, the energy of which is preferably in the range from 1 to 2500 eV, preferably from 50 to 1600 eV, and particularly preferably from 100 to 500 eV.

37. The process as claimed in claims 34 and 36, wherein the cleaning and activation are carried out in a single process step.

38. The process as claimed in one of claims 20 to 37, wherein the body to be coated, at least before the layer substances are deposited, is heated to process temperatures of up to 800°

C., and preferably of between 50°

C. and 550°

C., particularly preferably between 100°

C. and 350°

C.

39. The process as claimed in one of claims 20 to 38, wherein the coating operation comprises the polishing of the surface of the applied layer in at least one polishing step.

40. An arrangement for coating a body made from glass, glass-ceramic or another nonmetallic, crystalline material, in particular for coating a glass-ceramic hotplate, with a protective layer, in particular with a protective layer as claimed in claims 1 to 14,

comprising a coating installation, which has at least one coating chamber (4.1), the coating chamber (4.1) being a vacuum chamber, and the coating chamber (4.1) having a target (14) comprising the layer starting material, an excitation source for generating layer starting materials in atomic dimensions, an assisting ion beam source (12) directed onto the substrate (8), at least one process gas inlet valve (15) for feeding process gases into the coating chamber (4.1), and shutters (7) for feeding and discharging the substrate (8) to be coated into and out of the coating chamber (4.1),

wherein

the coating installation is directly connected, via a substrate transfer station (2.1) and an input lock (2.2), to the production installation (1) for the substrate (8) which is to be coated.

41. The arrangement as claimed in claim 40, wherein the excitation source is an ion beam excitation source (13).

42. The arrangement as claimed in claim 40, wherein the excitation source is a magnetron sputtering source.

43. The arrangement as claimed in one of claims 40 to 42, wherein the coating installation has a cleaning/activation chamber (3), the cleaning/activation chamber (3) being a vacuum chamber and having at least one cleaning/activation ion beam source (11) for cleaning and/or activating the substrate (8), and the cleaning/activation chamber (3) being arranged between the input lock (2.2) and the coating chamber (4.1) and being connected to them via shutters (7).

44. The arrangement as claimed in one of claims 40 to 43, wherein the coating installation has further coating chambers (4.n), where n>

1.

45. The arrangement as claimed in one of claims 40 to 44, wherein the coating installation has an aftertreatment chamber (5), the aftertreatment chamber (5) being a vacuum chamber and including at least one oxygen feed valve (16) and heating elements (9) and being connected, via a shutter (7), to the coating chamber (4.1) or a further coating chamber (4.n).

46. The arrangement as claimed in one of claims 40 to 45, wherein the coating chamber (4.1) or the further coating chambers (4.n) and the cleaning/activation chamber (3) have heating elements (9) for setting the coating temperature.

16. A protective layer for a body, which comprises at least one hard-material layer formed from a metal oxide and/or metal nitride and/or metal carbide and/or metal oxynitride and/or metal carbonitride and/or metal oxycarbonitride, wherein at least one hard-material layer, which comprises a metal oxide and/or metal nitride and/or metal carbide and/or metal oxynitride and/or metal carbonitride and/or metal oxycarbonitride, has laterally tightly cohesive, crystalline columns which grow perpendicular to the surface of the body, the lateral dimension of which is on average less than 1 μ

m, preferably less than 200 nm, and which has crystal orientations which, in columnar growth, predominantly have little tendency to widen out, with the surface roughness of the hard-material layer having an R_a value of <

50 nm, preferably an R_a value of <

20 nm.