Patent Publication Number: US-2012045614-A1

Title: Coating, article coated with coating, and method for manufacturing article

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to co-pending U.S. Patent Application (Attorney Docket No.US34382), entitled “COATING, ARTICLE COATED WITH COATING, AND METHOD FOR MANUFACTURING ARTICLE”, by Zhang et al. This application has the same assignee as the present application and has been concurrently filed herewith. The above-identified application is incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The exemplary disclosure generally relates to coatings, and particularly relates to articles coated with the coatings and method for manufacturing the articles. 
     2. Description of Related Art 
     With the development of wireless communication and information processing technology, portable electronic devices, such as mobile telephones and electronic notebooks are now in widespread use. External appearance of the housing of the portable electronic device is one of the key factors for attracting consumers. However, typical housings can be easily marred by fingerprints. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the exemplary coating, article coated with the coating and method for manufacturing the article. Moreover, in the drawings like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment. 
         FIG. 1  is a cross-sectional view of an exemplary embodiment of a coating. 
         FIG. 2  is a top view of the coating in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of an article coated with the coating in  FIG. 1 . 
         FIG. 4  is a diagram for manufacturing the article in  FIG. 2 . 
         FIG. 5  is a schematic view of a magnetron sputtering coating machine for manufacturing the article in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a coating  10  includes an anti-fingerprint layer  13 . The anti-fingerprint layer  13  comprises tin dioxide-aluminum oxide (SnO2-Al2O3). The anti-fingerprint layer  13  may be deposited by magnetron sputtering or cathodic arc deposition. The anti-fingerprint layer  13  has a thickness ranging from about 0.1 micrometer to about 1 micrometer. 
     The anti-fingerprint layer  13  includes an outer surface  131  and an opposite inner surface  132 . The anti-fingerprint layer  13  comprises a plurality of nano scale concavities  133  in the outer surface  131  so that the outer surface  131  has a dimpled surface. The concavities may be used for accommodating air around the anti-fingerprint layer  13 , to form a gaseous film on the outer surface  131 . The gaseous film can prevent grease and/or dirt from attaching to the anti-fingerprint layer  13 , providing good fingerprint resistance attribute to the anti-fingerprint layer  13 . It is to be understood that the coating  10  may include a decorative color layer  11  deposited on the inner surface  132 . 
     Referring to  FIG. 3 , an exemplary article  30  includes a substrate  20  and the coating  10  deposited on the substrate  20 . The substrate  20  may be made of metallic materials, such as high speed steel, aluminum, aluminum alloy, copper, copper alloy or magnesium alloy. The substrate  20  also may be made of non-metallic materials, such as plastic, ceramic, glass, or polymer. The article  30  may be a housing of an electronic device. 
     Referring to  FIGS. 4 and 5 , a method for manufacturing the article  30  may include at least the following steps: 
     Step  1  is implemented by providing the substrate  20 . The substrate  20  may be made of metallic materials, such as high speed steel, aluminum, aluminum alloy, copper, copper alloy or magnesium alloy. The substrate  20  also may be made of non-metallic materials, such as plastic, ceramic, glass, or polymer. 
     Step  2  is implemented by pretreating the substrate  20 . Firstly, the substrate  20  is washed with a solution (e.g., alcohol or acetone) in an ultrasonic cleaner to remove, e.g., grease, dirt, and/or impurities. Secondly, the substrate  20  is dried. Thirdly, the substrate  20  is retained on a rotating bracket  50  in a vacuum chamber  60  of a magnetron sputtering coating machine  100 . The vacuum level of the vacuum chamber  60  is about 8.0×10−3 Pa. Pure argon is pumped into the vacuum chamber  60  at a flux of about 300 standard cubic centimeters per minute (sccm) to 500 sccm from a gas inlet  90  for about 5-10 minutes, which washes the substrate  20  to further remove the grease or dirt. Thus, a binding ability between the substrate  20  and the anti-fingerprint layer  13  is enhanced. 
     Step  3  is implemented by depositing the anti-fingerprint layer  13  on the substrate  20 . The temperature in the vacuum chamber  60  is about 50˜180° C.; the speed of the rotating bracket  50  is about 1 to 3 revolutions per minute (rpm); argon is pumped into the vacuum chamber  60  at a flux from about 300 sccm to about 500 sccm and an oxygen is pumped into the vacuum chamber  60  at a flux from about 75 sccm to about 300 sccm from the gas inlet  90 ; a tin aluminum alloy target is evaporated in a power from about 2.5 to about 4.0 kw; a bias voltage applied to the substrate  20  is in a range from −50 to −150 volts for about 10 to about 60 min, to deposit the anti-fingerprint layer  13  on the substrate  20 . The tin aluminum alloy contains aluminum in a range from about 50 to about 95 wt %. 
     It is to be understood that the color layer  11  may be deposited on the anti-fingerprint layer  13 , to improve the appearance of the article  30 . 
     It is to be understood, however, that even through numerous characteristics and advantages of the exemplary disclosure have been set forth in the foregoing description, together with details of the system and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.