Yttria-sensitized zirconia

• US 10,420,226 B2
• Filed: 06/06/2017
• Issued: 09/17/2019
• Est. Priority Date: 09/21/2016
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Matsuyuki, Naoto, Memering, Dale N., Waniuk, Theodore A., Takagi, Kazuya, Ely, Colin M.
• Primary Examiner(s): Aughenbaugh, Walter
• Application Number:
  US15/614,747
• Publication Number:
  US 20180079686A1
• Time in Patent Office: 833 Days
• CPC Class Codes: B24C 1/04 for treating only selected parts of a surface, e.g. for carving stone or glass
• CPC Class Codes: B24C 1/06 for producing matt surfaces, e.g. on plastic materials, on glass
• CPC Class Codes: B24C 1/08 for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
• CPC Class Codes: B24C 11/00 Selection of abrasive materials or additives for abrasive blasts polishing compositions C09G
• CPC Class Codes: B32B 1/00 Layered products having a non-planar shape
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/76 Crystal structural characteristics, e.g. symmetry
• CPC Class Codes: C04B 2235/765 Tetragonal symmetry
• CPC Class Codes: C04B 2235/963 Surface properties, e.g. surface roughness
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/486 Fine ceramics
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/53 involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete C04B41/0036 - C04B41/0054 take precedence
• CPC Class Codes: C04B 41/91 involving the removal of part of the materials of the treated articles, e.g. etching
• CPC Class Codes: H01L 23/06 characterised by the material of the container or its electrical properties
• CPC Class Codes: H04M 1/0202 Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets constructional features of telephone transmitters or receivers, e.g. of speakers or microphones H04M1/03
• CPC Class Codes: H04M 1/0283 for providing a decorative aspect, e.g. customization of casings, exchangeable faceplate
• CPC Class Codes: H04M 1/18 Telephone sets specially adapted for use in ships, mines, or other places exposed to adverse environment H04M1/19 takes precedence
• CPC Class Codes: H04M 1/185 Improving the rigidity of the casing or resistance to shocks
• CPC Class Codes: H05K 5/0004 comprising several parts forming a closed casing
• CPC Class Codes: H05K 5/0017 : with operator interface units
• CPC Class Codes: H05K 5/02 : Details
• CPC Class Codes: H05K 5/0247 : Electrical details of casings, e.g. terminals, passages for cables or wiring

Abstract

A housing for a portable electronic device is disclosed. The housing is composed of yttria-sensitized zirconia. Yttria-sensitized zirconia has from about 1.5 to about 2.5 mole percent yttria, and more typically about 2 mole percent yttria, and most typically 2 mole percent yttria, in zirconia. Yttria-sensitized zirconia is both tough and able to limit the formation and propagation of micro-cracks. Methods for manufacturing yttria-sensitized zirconia composed housings are also disclosed.

Claims

1. An enclosure for an electronic device comprising:

a housing body defining an opening and composed of zirconia and from 1.5 mole percent yttria to 2.5 mole percent yttria;

a cover attached to the housing body and covering the opening to define an enclosed volume;

wherein;

a first surface of the housing body is polished;

the first surface has a first amount of monoclinic crystals;

at least a portion of a second surface of the housing body is roughened; and

the second surface has a second amount of monoclinic crystals that is greater than the first amount.

2. The enclosure of claim 1, wherein:

an internal portion of the housing body located between the first and second surfaces includes tetragonal phase zirconia; and

the first and second surfaces include a combination of monoclinic and tetragonal phase zirconia.

3. The enclosure of claim 1, wherein the at least a portion of the second surface of the housing body is roughened to form a roughened surface having a surface roughness Ra from about 0.05 to about 0.4 μ

m.

4. The enclosure of claim 3, wherein the roughened surface is formed over a stress-prone region having an increased likelihood of experiencing elevated stress as compared to other regions of the housing body.

5. The enclosure of claim 1, wherein the housing body is composed of zirconia and 2 mole percent yttria.

6. The enclosure of claim 1, wherein the housing body defines a bottom portion having multiple sidewalls extending therefrom.

7. The enclosure of claim 1, wherein the enclosed volume is configured to receive a display and multiple electronic components.

8. The enclosure of claim 1, wherein the electronic device is a wearable electronic device or a mobile phone.

9. An electronic device comprising:

a housing having an exterior surface and an interior surface, the housing composed of yttria-sensitized zirconia;

a display positioned within the housing; and

a cover positioned over the display;

wherein

the interior surface of the housing contains a higher percentage of zirconia monoclinic crystals than the exterior surface of the housing.

10. The electronic device of claim 9, wherein the yttria-sensitized zirconia is composed of zirconia and from 1.5 mole percent to 2.5 mole percent yttria.

11. The electronic device of claim 9, wherein the yttria-sensitized zirconia is composed of 2 mole percent yttria.

12. The electronic device of claim 9, wherein the exterior surface is polished.

13. The electronic device of claim 9, wherein the interior surface of the housing exhibits an increased resistance to micro-fracture propagation as compared to the exterior surface of the housing.

14. The electronic device of claim 9, wherein an internal portion of the housing located between the interior and exterior surfaces includes tetragonal phase zirconia.

15. A method of forming a housing substrate for an electronic device, comprising:

forming a housing substrate composed of yttria-sensitized zirconia, the housing substrate having an interior surface and an exterior surface;

polish at least a portion of the exterior surface; and

roughen at least a portion of the interior surface to induce a phase shift in the yttria-sensitized zirconia and produce an increased amount of monoclinic crystals as compared to the exterior surface.

16. The method of claim 15, wherein the yttria-sensitized zirconia is composed of zirconia and from 1.5 mole percent yttria to 2.5 mole percent yttria.

17. The method of claim 15, wherein the exterior surface and interior surface have a greater amount of monoclinic crystals as compared to an internal portion of the housing substrate located between the exterior and interior surfaces.

18. The method of claim 15, wherein roughening the portion of the interior surface of the housing substrate increases a resistance to micro-crack propagation as compared to the exterior surface of the housing substrate.

19. The housing of claim 15, wherein the roughened portion of the interior surface results in a surface roughness having an Ra from 0.05 to 0.4 μ

m.

20. The method of claim 15, wherein:

the roughening is performed by blasting the interior surface with alumina particles; and

the polishing is performed by applying a diamond resin pad to the exterior surface.