Patent Application
20120062081
1. Technical Field
The disclosure generally relates to housings for electronic devices and method for manufacturing the housings.
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. Aluminum alloy has good heat dissipation and can effectively shield electromagnetic interference so aluminum alloy are widely used to manufacture housings of the portable electronic devices. However, aluminum alloy has a low corrosion resistance.
Therefore, there is room for improvement within the art.
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 housing and method for manufacturing the housing. 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.
Referring to
Referring to
A substrate 11 is provided. The substrate 11 may be made of aluminum alloy and may be molded by a punching method.
The substrate 11 is pretreated. First, the substrate 11 is treated to remove oxide film on surface thereof by mechanical lapping, until the substrate 11 has a surface roughness Rz is less than 1.2 micrometer. Second, the substrate 11 is washed with a solution (e.g., alcohol or acetone) in an ultrasonic cleaner to remove grease, dirt, and/or impurities. The substrate 11 is then dried.
An aluminum layer 13 is deposited on the substrate 11. In an exemplary embodiment, the substrate 11 is retained on a rotating bracket 50 in a vacuum chamber 60 of a vacuum coating machine 100. The temperature in the vacuum chamber 60 is adjusted to about 50° C. to about 180° C. The vacuum level of the vacuum chamber 60 is adjusted to about 8.0×10−3 Pa. Pure argon (99.999%) is pumped into the vacuum chamber 60 at a flux of about 100 standard cubic centimeters per minute (sccm) to about 300 sccm from a gas inlet 90. A bias voltage is applied to the substrate 11 in a range from about −50 volts to about −300 volts. An aluminum target 70 is evaporated at a power from about 5 kw to about 10 kw for about 30 minutes to about 90 minutes, to deposit the aluminum layer 13 on the substrate 11. In another embodiment, the substrate 11 may be processed by cathodic arc deposition, ion implantation or plasma cleaning.
The electrode potential of aluminum is equivalent to the electrode potential of aluminum alloy, so it is difficult to cause galvanic corrosion between the substrate 11 and the aluminum layer 13. Thus, the aluminum layer 13 can improve the corrosion resistance of the substrate 11. Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact and immersed in an electrolyte.
An ion implantation layer 15 is formed on the aluminum layer 13 by ion implantation process. The vacuum level of the vacuum chamber 60 is adjusted to about 3.0×10−3 Pa. Pure oxygen (99.999%) is pumped to an ion source 80 in the vacuum coating machine 100 from the gas inlet 90. The ion source 80 is started at a power from about 0.5 kw to about 5 kw for about 30 minutes to about 120 minutes, to produce ions of oxygen. The ions of oxygen produced by the ion source 80, are then electrotatically accelerated to a high energy, and the aluminum layer 13, i.e., the ions of oxygen are implanted into the aluminum layer 13. During this processing, the physical properties of the aluminum layer 13 is changed, to produce the ion implantation layer 15 mainly comprising aluminum(II) oxide (AlO) solid solution phase and aluminum oxide (Al2O3) solid solution phase. The aluminum(II) oxide (AlO) solid solution phase and Al2O3 solid solution phase can prevent columnar crystal from forming in the ion implantation layer 15, thereby improving the compactness of the ion implantation layer 15. Thus, the corrosion resistance of the housing 10 can be improved.
Depending on the embodiment, certain of the steps described below may be removed, others may be added, and the sequence of steps may be altered. It is also to be understood that the description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps.
It is to be understood, however, that even through numerous characteristics and advantages of the 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010278414.2 | Sep 2010 | CN | national |
