Alloy member and method for hardening surface thereof

Patent metadata

Field	Value
Publication number	US-2023167533-A1
Application number	US-202318097536-A
Country	US
Kind code	A1
Filing date	Jan 17, 2023
Priority date	Jan 3, 2017
Publication date	Jun 1, 2023
Grant date	—

Abstract

The present disclosure relates to a titanium or titanium alloy member and to a surface hardening method for the titanium or titanium alloy member. The titanium or titanium alloy member includes a base material of titanium or titanium alloy, and at a surface of the base material, a hardened layer formed by diffusion of oxygen into the surface.

First claim

1 . An alloy member comprising:
a base material of titanium or titanium alloy; and at a surface of the base material, a hardened layer formed by diffusion of oxygen into the surface.

2 . The alloy member according to claim 1 , wherein
the hardened layer includes (i) a surface transparent oxide layer, and (ii) a diffusion layer disposed internally from the surface transparent oxide layer.

3 . The alloy member according to claim 2 , wherein the diffusion layer is thicker than the surface transparent oxide layer.

4 . The alloy member according to claim 1 , wherein
the hardened layer includes, in order inwardly from the surface of the base material, a surface transparent oxide layer, an external diffusion layer, and an internal diffusion layer, the external diffusion layer includes a portion having a hardness greater than or equal to 300 Hv, the portion being disposed internally from the surface transparent oxide layer, and the internal diffusion layer includes a portion having a hardness less than 300 Hv.

5 . The alloy member according to claim 4 , wherein
a concentration of oxygen dissolved in solid solution in the external diffusion layer is higher than that in the internal diffusion layer, and the concentration of oxygen dissolved in solid solution in the internal diffusion layer gradually decreases from outside towards inside.

6 . The alloy member according to claim 4 , wherein
concentrations of oxygen and nitrogen dissolved in solid solution in the external diffusion layer are higher than those in the internal diffusion layer, and the concentrations of oxygen and nitrogen dissolved in solid solution in the internal diffusion layer gradually decrease from outside towards inside.

7 . The alloy member according to claim 4 , wherein the surface transparent oxide layer is thinner than the external diffusion layer and the internal diffusion layer.

8 . The alloy member according to claim 7 , wherein
a concentration of oxygen dissolved in solid solution in the external diffusion layer is higher than that in the internal diffusion layer, and the concentration of oxygen dissolved in solid solution in the internal diffusion layer gradually decreases from outside towards inside.

9 . The alloy member according to claim 1 , wherein the titanium or titanium alloy member is applicable to a casing component of a wristwatch or a clock.

10 . The alloy member according to claim 9 , wherein the casing component includes a bezel, a bezel center region, a back cover, or a band.

11 . An alloy member comprising:
a base material of titanium or titanium alloy; and at a surface of the base material, a hardened layer formed by diffusion of nitrogen and oxygen into the surface.

12 . The alloy member according to claim 11 , wherein
the hardened layer includes (i) a surface transparent oxide layer, and (ii) a diffusion layer disposed internally from the surface transparent oxide layer.

13 . The alloy member according to claim 12 , wherein the diffusion layer is thicker than the surface transparent oxide layer.

14 . The alloy member according to claim 11 , wherein
the hardened layer includes, in order inwardly from the surface of the base material, a surface transparent oxide layer, an external diffusion layer, and an internal diffusion layer, the external diffusion layer includes a portion having a hardness greater than or equal to 300 Hv, the portion being disposed internally from the surface transparent oxide layer, and the internal diffusion layer includes a portion having a hardness less than 300 Hv.

15 . The alloy member according to claim 14 , wherein
a concentration of oxygen dissolved in solid solution in the external diffusion layer is higher than that in the internal diffusion layer, and the concentration of oxygen dissolved in solid solution in the internal diffusion layer gradually decreases from outside towards inside.

16 . The alloy member according to claim 14 , wherein
concentrations of oxygen and nitrogen dissolved in solid solution in the external diffusion layer are higher than those in the internal diffusion layer, and the concentrations of oxygen and nitrogen dissolved in solid solution in the internal diffusion layer gradually decrease from outside towards inside.

17 . The alloy member according to claim 14 , wherein the surface transparent oxide layer is thinner than the external diffusion layer and the internal diffusion layer.

18 . The alloy member according to claim 17 , wherein
a concentration of oxygen dissolved in solid solution in the external diffusion layer is higher than that in the internal diffusion layer, and the concentration of oxygen dissolved in solid solution in the internal diffusion layer gradually decreases from outside towards inside.

19 . The alloy member according to claim 11 , wherein the titanium or titanium alloy member is applicable to a casing component of a wristwatch or a clock.

20 . The alloy member according to claim 19 , wherein the casing component includes a bezel, a bezel center region, a back cover, or a band.

Assignees

• Casio Computer Co Ltd

Inventors

• Sato Junichi
• Kobayashi Kazuma
• Nagasawa Shouta
• Inoue Kenichi
• Liu Chinfu
• Liu Wuchien
• Lin Tienchai
• Kao Weipin

Classifications

• C23C8/10 Primary

  Oxidising · CPC title

• C22F1/00

  Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24) · CPC title

• C22C14/00

  Alloys based on titanium · CPC title

• C23C8/12

  using elemental oxygen or ozone · CPC title

• C22F1/02

  in inert or controlled atmosphere or vacuum (adjusting the composition of the atmosphere C21D1/76) · CPC title