Patent Application
20120107606
1. Technical Field
The disclosure generally relates to articles made of aluminum or aluminum alloy and method for manufacturing the articles.
2. Description of Related Art
Due to having many good properties such as light weight and quick heat dissipation, aluminum and aluminum alloy are widely used in manufacturing components (such as housings) of electronic devices. However, aluminum and aluminum alloy have a relatively low erosion 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 article made of aluminum or aluminum alloy 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.
The insulating coating 13 is directly formed on a surface of the substrate 11. The insulating coating 13 is electrically insulating and may be composed of an insulating ceramic material, such as silicon oxide and aluminum oxide. In this exemplary embodiment, the insulating coating 13 is composed of silicon oxide. In the embodiment, the insulating coating 13 has a light color, such as silver, white, or gray, so it does not interfere with the color of the anticorrosive coating 15. The thickness of the insulating coating 13 may be from about 2.0 μm to about 3.0 μm.
The anticorrosive coating 15 is directly formed on the insulating coating 13. The anticorrosive coating 15 is a ceramic coating. The anticorrosive coating 15 may be composed of one ceramic material selected from the group consisting of TiN, TiON, TiCN, CrN, CrON, and CrCN. In this exemplary embodiment, the anticorrosive coating 15 is composed of TiN. The thickness of the anticorrosive coating 15 may be from about 0.5 μm to about 3.0 μm.
The insulating coating 13 and the anticorrosive coating 15 may be formed by physical vapor deposition (PVD), such as magnetron sputtering, or arc ion plating.
The insulating coating 13 set between the substrate 11 and the anticorrosive coating 15 is electrically insulating. When the article 10 is placed in a corrosive condition, the insulating coating 13 separates the substrate 11 from the anticorrosive coating 15, thereby the substrate 11 and the anticorrosive coating 15 cannot form the cathode and anode required by electrochemical corrosion. Thus, the corrosion resistance of the article 10 can be improved.
An exemplary process manufacturing the article 10 may include the following steps.
Referring to
The substrate 11 is pretreated. For example, the substrate 11 is ground and electrolytic polished to produce a smooth surface. The substrate 11 is cleaned with a solution (e.g., alcohol or acetone) in an ultrasonic cleaner, to remove impurities such as grease or dirt from the substrate 11. Then, the substrate 11 is dried.
The insulating coating 13 is directly formed on the substrate 11 by a PVD method, such as magnetron sputtering and arc ion plating. In this exemplary embodiment, the insulating coating 13 is formed by magnetron sputtering. Before depositing the insulating coating 13, the substrate 11 is cleaned by argon plasma cleaning. The substrate 11 is hold on a rotating bracket 33 in a vacuum chamber 31 of a magnetron sputtering machine 30 as shown in
Once the argon plasma cleaning is finished, argon and oxygen are simultaneously fed into the vacuum chamber 31, with the argon as a sputtering gas, and the oxygen as a reactive gas. The flux of the argon supplied into the vacuum chamber 31 is adjusted to be about 150 sccm to about 300 sccm. The flux of the oxygen is about 50 sccm to about 200 sccm. The temperature in the vacuum chamber 31 is maintained at about 50° C. to about 150° C. A bias voltage is applied to the substrate 11 in a range of about −50 V to about −300 V. First targets 35 made of aluminum or silicon are evaporated at an electric power of about 5 kW to about 13 kW, depositing the insulating coating 13 on the substrate 11. Deposition of the insulating coating 13 may take about 30 min to about 120 min. The electric power may be a medium-frequency AC power, with a duty cycle of about 30% to about 70%.
The anticorrosive coating 15 is then formed on the insulating coating 13 by a PVD method, such as magnetron sputtering and arc ion plating. In this exemplary embodiment, the anticorrosive coating 15 is formed by magnetron sputtering. This step may be carried out in the same magnetron sputtering machine 30. When the anticorrosive coating 15 is composed of TiN or CrN, this step can be carried out as the following steps.
The first targets 35 are switched off. The temperature inside the vacuum chamber 31 is maintained at about 50° C. to about 150° C. Argon and nitrogen are simultaneously supplied into the vacuum chamber 31, with the argon as a sputtering gas, and the nitrogen as a reactive gas. The flux of argon is in a range of about 150 sccm to about 300 sccm. The flux of nitrogen is about 10 sccm to about 120 sccm. A bias voltage is applied to the substrate 11 in a range of about −50 V to about −300 V. Second targets 37 made of titanium or chromium are evaporated at an electric power of about 5 kW to about 10 kW, depositing the anticorrosive coating 15 in the form of a TiN layer on the insulating coating 13. Deposition of the anticorrosive coating 15 may take from about 20 min to about 60 min.
The insulating coating 13 may be composed of insulating polymers, such as polytetrafluoroethylene. When the insulating coating 13 is composed of polymers, the insulating coating 13 may be formed by chemical vapor deposition.
When the anticorrosive coating 15 is composed of TiON or CrON, oxygen and nitrogen can be fed into the vacuum chamber 31 as the reactive gases when forming the anticorrosive coating 15.
When the anticorrosive coating 15 is composed of TiCN or CrCN, nitrogen and a gas for offering carbon, such as methane or acetylene, can be fed into the vacuum chamber 31 as the reactive gases when forming the anticorrosive coating 15.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010523201.1 | Oct 2010 | CN | national |
