Decorative ceramic item

Patent metadata

Field	Value
Publication number	US-12344559-B2
Application number	US-201917298860-A
Country	US
Kind code	B2
Filing date	Nov 11, 2019
Priority date	Dec 7, 2018
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

A decorative item is made of a ceramic material, where ceramic material includes a carbide phase and an oxide phase, the carbide phase being present in a percentage by volume comprised between 50 and 95% and the oxide phase being present in a percentage by volume comprised between 5 and 50%. The decorative item is manufactured by a method of powder metallurgy.

First claim

The invention claimed is:

1. A decorative item, comprising:
a ceramic material comprising (i) Mo 2 C in range of from 70 to 85 vol. %
and (ii) Al 2 O 3 in a range of from 15 to 30 vol. %,
wherein the item has a hardness HV 30 in a range of from greater than 1319 to 1800 and a toughness K iC in a range of from 3.5 to 8.5 MPa·m 1/2 .

2. The item of claim 1 , wherein the ceramic material further comprises niobium carbide in a minor proportion.

3. The item of claim 1 , wherein the Mo 2 C is present in a range of from 70 to 75 vol. %, and
wherein the Al 2 O 3 is present in a range of from 25 to 30 vol. %.

4. The item of claim 1 , further comprising:
chromium oxide in a minor proportion.

5. The item of claim 1 , having, in a CIELAB color space, a luminance component L* in a range of from 60 to 85.

6. The item of claim 5 , having a red component a* in a range of from −1 to 5, and a yellow component b* in a range of from −2 to 5.

7. The item of claim 6 , wherein the components a* and b* are 0.

8. The item of claim 1 , which is a timepiece external component which is a middle, a back, a bezel, a push-button, a bracelet link, a dial, a hand, or a dial index.

9. The item of claim 1 , wherein the carbide phase comprises tungsten carbide in minor proportion.

10. The item of claim 1 , wherein the ceramic material consists of Mo 2 C, Al 2 O 3 , and inevitable impurities.

11. The item of claim 1 , having a hardness HV 30 in a range of from 1319 to 1417.

12. The item of claim 1 , having a toughness K iC in a range of from 5.0 to 5.3 MPa·m 1/2 .

13. The item of claim 1 , having, in a CIELAB color space, a luminance component L* in a range of from 63.8 to 72.5.

14. The item of claim 1 , having a red component a* in a range of from 0.13 to 0.23, and a yellow component b* in a range of from 1.49 to 2.

15. The item of claim 1 , having, in a CIELAB color space,
a luminance component L* in a range of from 63.8 to 72.5,
a red component a* in a range of from 0.13 to 0.23, and
a yellow component b* in a range of from 1.49 to 2.

16. A decorative item, comprising:
a ceramic material comprising (i) Mo 2 C in range of from 51 to 72 vol. %
and (ii) Al 2 O 3 in a range of from 28 to 49 vol. %
wherein the item has a hardness HV 30 in a range of from 1319 to 1800 and a toughness K iC in a range of from 3.5 to 8.5 MPa·m 1/2 .

17. The item of claim 16 , having, in a CIELAB color space,
a luminance component L* in a range of from 63.8 to 72.5,
a red component a* in a range of from 0.13 to 0.23, and
a yellow component b* in a range of from 1.49 to 2.

18. The item of claim 1 , having a hardness HV 30 in a range of from 1319 to 1417, and
having a toughness K iC in a range of from 5.0 to 5.3 MPa·m 1/2 .

19. The item of claim 18 , wherein the Mo 2 C is present in a range of from 70 to 75 vol. %, and
wherein the Al 2 O 3 is present in a range of from 25 to 30 vol. %.

20. The item of claim 17 , wherein the Mo 2 C is present in a range of from 50 to 60 vol. %, and
wherein the Al 2 O 3 is present in a range of from 40 to 50 vol. %.

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Bertheville Bernard
• Fallet Yann

Classifications

• G04B45/0076

  Decoration of the case and of parts thereof, e.g. as a method of manufacture thereof (specially shaped G04B45/0061, G04B45/0069; decoration with inscriptions and pictures G04B45/0084; construction of the hands G04B19/042; decoration by adding extra pieces to the clockwork G04B47/04; colouring by treatment of the surface, e.g. by oxidation C25D) · CPC title

• C04B2235/9661

  Colour · CPC title

• C04B2235/80

  Phases present in the sintered or melt-cast ceramic products other than the main phase · CPC title

• C04B2235/3847

  Tungsten carbides · CPC title

• C04B2235/3843

  Titanium carbides · CPC title