Anodic oxide based composite coatings of augmented thermal expansivity to eliminate thermally induced crazing

• US 10,711,363 B2
• Filed: 12/16/2015
• Issued: 07/14/2020
• Est. Priority Date: 09/24/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Curran, James A., Counts, William A., Feinberg, Zechariah D.
• Primary Examiner(s): Walshon, Scott R.
• Assistant Examiner(s): Vazquez, Elaine M
• Application Number:
  US14/971,829
• Publication Number:
  US 20170088968A1
• Time in Patent Office: 1,672 Days
• Field of Search: None
• CPC Class Codes: C25D 11/20 Electrolytic after-treatment
• CPC Class Codes: C25D 11/22 for colouring layers
• CPC Class Codes: C25D 11/246 for sealing layers
• CPC Class Codes: C25D 13/12 characterised by the article coated
• CPC Class Codes: C25D 7/00 Electroplating characterised by the article coated
• CPC Class Codes: C25D 9/02 with organic materials
• CPC Class Codes: G06F 1/1613 for portable computers cooling arrangements therefor G06F1/203; constructional details or arrangements for pocket calculators, electronic agendas or books G06F15/0216; constructional details of portable telephone sets: with several bodies H04M1/0202
• CPC Class Codes: G06F 1/1656 Details related to functional adaptations of the enclosure, e.g. to provide protection against EMI, shock, water, or to host detachable peripherals like a mouse or removable expansions units like PCMCIA cards, or to provide access to internal components for maintenance or to removable storage supports like CDs or DVDs, or to mechanically mount accessories mounting of accessories to a computer display G06F1/1607; display hoods G06F1/1603; cooling arrangements for portable computers G06F1/203
• CPC Class Codes: G06F 1/203 for portable computers, e.g. for laptops
• CPC Class Codes: H04M 1/0283 for providing a decorative aspect, e.g. customization of casings, exchangeable faceplate
• CPC Class Codes: H04M 1/185 Improving the rigidity of the casing or resistance to shocks

Abstract

A process is disclosed for minimizing the difference in thermal expansivity between a porous anodic oxide coating and its corresponding substrate metal, so as to allow heat treatments or high temperature exposure of the anodic oxide without thermally induced crazing. A second phase of higher thermal expansivity than that of the oxide material is incorporated into the pores of the oxide in sufficient quantity to raise the coating'"'"'s thermal expansion coefficient. The difference in thermal expansion between the anodic oxide coating and underlying metal substrate is reduced to a level such that thermal exposure is insufficient for any cracking to result. The second phase may be an electrodeposited metal, or an electrophoretically deposited polymer. The second phase may be uniformly deposited to a certain depth, or may be deposited at varying amounts among the pores.

Claims

1. An anodized part, comprising:

an aluminum alloy substrate comprising a first coefficient of thermal expansion;

a sealed anodic oxide coating disposed on the aluminum alloy substrate, the sealed anodic oxide coating comprising a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion, the sealed anodic oxide coating defining a plurality of pores; and

a thermal expansion compensating polymer deposited within the plurality of pores, the thermal expansion compensating polymer comprising a coefficient of thermal expansion greater than the second coefficient of thermal expansion such that the sealed anodic oxide coating comprises an adjusted coefficient of thermal expansion greater than the second coefficient of thermal expansion.

2. The anodized part of claim 1, wherein the thermal expansion compensating polymer comprises at least one of an epoxy or acrylic.

3. The anodized part of claim 1, wherein a deposit thickness of the thermal expansion compensating polymer is 2 micrometers or greater.

4. The anodized part of claim 1, further comprising dye particles that are deposited within the plurality of pores and impart the sealed anodic oxide coating with a predetermined color, wherein the dye particles overlay the thermal expansion compensating polymer.

5. The anodized part of claim 1, wherein the thermal expansion compensating polymer has a varied distribution within the plurality of pores such as to impart the sealed anodic oxide coating with a thermal expansivity gradient.

6. The anodized part of claim 1, wherein the coefficient of thermal expansion of the thermal expansion compensating polymer is less than the first coefficient of thermal expansion.

7. The anodized part of claim 1, wherein the plurality pores of the sealed anodic oxide coating are sealed with a sealant material, the sealant material being different from the thermal expansion compensating polymer.

8. The anodized part of claim 1, wherein the thermal expansion compensating polymer increases as in-plane thermal expansivity of the sealed anodic oxide coating.