Decorative product and timepiece

Abstract

A decorative product having a base member composed of primarily an Fe—Cr alloy, and an austenite layer that is austenitized by adding nitrogen atoms near the surface of the base member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG. 1 is a cross-sectional view schematically showing a decorative product (member) according to a preferred embodiment of the present invention;

FIGS. 2A and 2B are cross-sectional views schematically illustrating a method of manufacturing the decorative product according to the preferred embodiment of the present invention;

FIG. 3 is a partial cross-sectional view schematically illustrating of a timepiece (portable timepiece) according to the preferred embodiment the present invention; and

FIG. 4 is a plan view of the timepiece that has the decorative product.

Claims

1. A decorative member, comprising: a base member having an austenite layer austenitized and primarily made of an Fe—Cr alloy, anda base portion primarily made of an Fe—Cr alloy.

2. The decorative member according to claim 1, wherein a thickness of the austenite layer is 5 μm to 500 μm.

3. The decorative member according to claim 2, wherein the thickness of the austenite layer is 150 μm to 350 μm.

4. The decorative member according to claim 1, wherein nitrogen content in the austenite layer is 0.3 wt % to 1.2 wt %.

5. The decorative member according to claim 4, wherein nitrogen content in the austenite layer is 0.8 wt % to 1.2 wt %.

6. The decorative member according to claim 1, wherein Ni content in the base member is less than or equal to 0.05 wt %.

7. The decorative member according to claim 1, wherein the base member is further made of one of the group consisting Mo, Nb, Mn, Si, Zr and Ti.

8. The decorative member according to claim 1, wherein the austenite layer has a Vickers hardness Hv of 350 or higher.

9. The decorative member according to claim 8, wherein the austenite layer has a Vickers hardness Hv of 400 or higher.

10. The decorative article member according to claim 1, wherein a thickness of the austenite layer is 150 μm to 350 μm,nitrogen content in the austenite layer is 0.8 wt % to 1.2 wt %,Ni content in the base member is less than or equal to 0.05 wt %,the base member is further made of one of the group consisting Mo, Nb, Mn, Si, Zr and Ti, andthe austenite layer has a Vickers hardness Hv of 400 or higher.

11. A timepiece, comprising: a drive unit;a time display being connected to the drive unit and displaying time information; anda case housing the drive unit and the time display, the case having; a base member having an austenite layer austenitized and primarily made of an Fe—Cr alloy, anda base portion primarily made of an Fe—Cr alloy.

12. The timepiece according to claim 11, further comprising an external part connected to the case, the external part having a base member having an austenite layer austenitized and primarily made of an Fe—Cr alloy, anda base portion primarily made of an Fe—Cr alloy.

13. The timepiece according to claim 12, wherein the external part is one of the group consisting a bezel, crown, back cover, and a band.

14. The timepiece according to claim 11, wherein a thickness of the austenite layer is 5 μm to 500 μm.

15. The timepiece according to claim 11, wherein nitrogen content in the austenite layer is 0.3 wt % to 1.2 wt %.

16. The timepiece according to claim 11, wherein Ni content in the base member is less than or equal to 0.05 wt %.

17. The timepiece according to claim 11, wherein the base member is further made of one of the group consisting Mo, Nb, Mn, Si, Zr and Ti.

18. A method for making a decorative product, comprising: preparing a base member primarily made of an Fe—Cr alloy;washing the base member;depressurizing a surrounding area of the base member;introducing nitrogen to the area to austenitize the base member; andheating the area to a first temperature of 1200° C.

19. The method of making a decorative product according to claim 18, further comprising, holding the first temperature for 12 hours, and quenching the base member to a second temperature of 30° C.