Abstract:
A housing for electronic device, comprising: a substrate, the substrate having an outer surface; a metallic coating formed on at least the outer surface of the substrate, the metallic coating defining a plurality of grooves thereon and forming a pattern; and a metal pattern layer formed in the grooves. A method for making the present housing is also provided.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to housings for electronic devices, especially to a housing having decorative metal patterns, and a method for making the housing. 
         [0003]    2. Description of Related Art 
         [0004]    Housings for electronic devices, such as mobile phones, decorated with gold may be more attractive. Gold ornaments can be fusion welded on housings. Specifically, a gold welding rod is melted and filled into a groove to form an ornament. However, it is difficult to accurately control the quantity of gold melted into the grooves, resulting in too little or too much gold being used which may degrade the appearance of the housing. Furthermore, fusion welding is only suitable for inlaying simple and large ornaments, so, it is difficult to form complex metal patterns on housing by fusion welding. 
         [0005]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the housing for electronic device and method for making the housing can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present housing and the method for making the same. 
           [0007]      FIG. 1  is a schematic front elevational view of an exemplary embodiment of the present housing. 
           [0008]      FIG. 2  is a schematic cross-section view of the housing shown in  FIG. 1 . 
           [0009]      FIG. 3  is a schematic drawing of forming a plurality of curve grooves on a substrate of an exemplary process for making the housing shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0010]      FIGS. 1 and 2  show an exemplary housing  10  for an electronic device such as a mobile phone. The housing  10  includes a substrate  11 , a metallic coating  12 , and a metal pattern layer  13 . 
         [0011]    The substrate  11  can be made of metal selected from the group consisting of stainless steel, magnesium alloy, aluminum alloy, and titanium alloy. The substrate  11  is stainless steel in this exemplary embodiment. The substrate  11  has an outer surface  110 . 
         [0012]    The metallic coating  12  is formed on at least the outer surface  110  of the substrate  11  by electroplating or physical deposition (such as vacuum evaporation or vacuum sputtering). The metallic coating  12  comprises a metal material having a first color, such as chromium, formed by electroplating. The metallic coating  12  defines a plurality of grooves  122  (as shown in  FIG. 3 ) therein. The grooves  122  may be curved and in combination with each other define a desired pattern. 
         [0013]    The metal pattern layer  13  fills the grooves  122 . The metal pattern layer  13  may be coplanar with or protrude above the metallic coating  12 . The metal pattern layer  13  may comprise a noble material such as gold, platinum, or imitation gold. The metal pattern layer  13  has a second color different from the first color of the metallic coating  12 . 
         [0014]    An exemplary method for making the housing  10  may include the following steps. 
         [0015]    A substrate  11  is provided. The substrate  11  has the outer surface  110 . 
         [0016]    The substrate  11  is pretreated by degreasing and subsequently activating. When the substrate  11  is made of stainless steel, the substrate  11  can be activated in a hydrochloric acid solution containing trivalent iron. 
         [0017]    The metallic coating  12  is formed on at least the outer surface  110  by, e.g., electroplating, vacuum evaporation, or vacuum sputtering. For example, the metallic coating  12  may be a chrome coating formed by electroplating. The electroplating process may be carried out in an electrolyte of 28˜25° C. containing a chromic salt, buffers of pH, and necessary additives, at a current density of about 3˜20 A/dm 2  (ampere per square decimeter). 
         [0018]    Referring to  FIG. 3 , the substrate  12  with the metallic coating  12  is coated with a protective layer  14 . The protective layer  14  may be a resin that is resistant to chemical etching and formed by electrophoresis. Alternatively, the protective layer  14  can be a chemical-etching resistant paint sprayed on the metallic coating  12 . 
         [0019]    Portions of the protective layer  14  and the corresponding metallic coating  12  are removed by, for example, laser carving. The plurality of grooves  122  are defined in the metallic coating  12 . 
         [0020]    The substrate  11  having the grooves  122  is then electroplated to form a metal pattern layer  13  within the grooves  122 . The metal pattern layer  13  may be coplanar with or protrude above the metallic coating  12 . 
         [0021]    The protective layer  14  is removed. The method for removing the protective layer  14  depends on the respective material of the metallic coating  12  and the metal pattern layer  13 . For example, when the metallic coating  12  is made of chrome and the metallic pattern layer  13  is made of gold which are both resistant to strong acids, 98% (by weight) sulfuric acid can be used to remove the protective layer  14 . 
         [0022]    The substrate  11  can be made of plastic. Accordingly, when the metallic coating  12  is formed by electroplating, the substrate  11  may be processed to be electroconductive before electroplating the metallic coating  12 . 
         [0023]    When the metallic coating  12  is electroplated with chrome, an electroless plated nickel layer and an electroplated copper layer can be formed between the substrate  11  and the metallic coating  12 , for strengthening the bonding of the metallic coating  12  and the substrate  11 . 
         [0024]    It should be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, 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 invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.