Patent Application
20090047505
1. Field of the Invention
The present invention relates to a shell and a method used to manufacture the shell, particularly to an aluminum alloy shell and a method for making the aluminum alloy shell.
2. Description of Related Art
Generally, an aluminum alloy shell is widely used in an electronic device, especially a portable electronic device, for its lightweight. The aluminum alloy shell typically has a protective layer formed on an exterior surface thereof. The protective layer is used to protect the aluminum alloy shell from being damaged (e.g., being scuffed, or the like).
The protective layer is typically an anodic oxide film, which is formed/deposited on the exterior surface of the aluminum alloy shell during anodic oxidizing process. However, hardness of the anodic oxide film is relatively low. Thus, the cohesive/binding force between the anodic oxide film and the exterior surface is relatively weak. Moreover, capabilities of wear resisting and corrosion resisting are relatively weak. As a result of that, the anodic oxide film tends to depart from the exterior surface and also tends to be abraded or corrosion damaged. The life of the aluminum alloy shell is thus shortened.
Therefore, a heretofore-unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.
In one aspect, an aluminum alloy shell is provided. The aluminum alloy shell includes a base shell and a microarc oxidation coating. The microarc oxidation coating is formed on a surface of the base shell by micro arc oxidation processing.
In another aspect, a manufacturing method for making the present aluminum alloy shell is provided. The manufacturing method includes steps as follows. The base shell is pretreated. The pretreated base shell is microarc oxidized to form the microarc oxidation coating thereon. The aluminum alloy shell is post treated by washing and drying.
These and other aspects of the present invention will become more apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.
Many aspects of the present aluminum alloy shell and the manufacturing method making the aluminum alloy shell can be better understood with reference to the following drawings. These drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present aluminum alloy shell and the manufacturing method making the aluminum alloy shell. 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.
The present aluminum alloy shell and the method for making the aluminum alloy shell is described here in conjunction with the accompanying drawings in
Referring to
Referring also to
The electrical source 21 can produce voltages of over 200V. These voltages can be continuous DC (Direct Current) voltages or pulsed DC voltages, or alternating pulsed voltages. In this embodiment, the voltages are pulsed DC voltages.
The electrolytic bath 22 usually consists of a dilute alkaline solution 26 such as KOH. In this embodiment, the electrolytic bath 22 consists of a dilute alkaline solution 26 containing sodium hexametahposphate (10 g/l˜20 g/l), sodium silicate (5 g/l˜10 g/l), sodium molybdate (10 g/l˜15 g/l), sodium carbonate (5 g/l˜8 g/l), and sodium tungstate (2 g/l˜5 g/l). The PH (potential of hydrogen) value of the dilute alkaline solution 26 is within a range of 8 to 12.
The base shell 11 of the aluminum alloy shell 10 electrically connects with the electrical source 21 as one of the electrodes (e.g., anode) during MAO process. The electrode 24, being a stainless steel pole, electrically connects with the electrical source 21 for functioning as a counter-electrode (e.g., cathode) during MAO process.
Referring further to
First step is to provide the base shell 11 pretreated by degreasing (e.g., using alcohol or acetone) and washing (e.g., using water).
Second step is to immerse the pretreated base shell 11 into the dilute alkaline solution 26 contained in the electrolytic bath 22.
Third step is to electrically connect the pretreated base shell 11 with the electrical source 21.
Fourth step is to microarc oxidize the pretreated base shell 11 so as to deposit the microarc oxidation coating 12 (i.e., aluminum oxide coating) on the surface of the pretreated base shell 11. In this case, the electrical source 21 produces voltages in a range of 50-350V and intensity of pulsed DC in a range of 3-5 A/dm2, which are applied to the pretreated base shell 11 and the electrode 24 within the dilute alkaline solution 26 for 10-20 minutes. The microarc oxidation coating 12, with an 8-20 μm thickness, is thus fabricated on the surface of the pretreated base shell 11. The aluminum alloy shell 10 is manufactured.
Fifth step is to extract the aluminum alloy shell 10 from the dilute alkaline solution 26 and then has it post treated by washing (e.g., using water) and drying (e.g., oven drying).
One main advantage of the present embodiment embodies that the microarc oxidation coating 12 obtained by MAO has high adhesion, high Vickers hardness up to 25 Gpa, high erosion/abrasion wear resistance, high thermal shock resistance, and dielectric properties. The base shell 11 of the aluminum alloy shell 10 with the microarc oxidation coating 12 can thus be effectively protected against abrasion, erosion, heat, or thermal shocking as well as electrical insulation.
It is to be understood, however, that even through numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200710076406.8 | Aug 2007 | CN | national |
