TWI472637B - Surface treatment for aluminum alloy and housing manufactured by the aluminum alloy - Google Patents

Description

Surface treatment method of aluminum alloy and shell made of aluminum alloy

The invention relates to a surface treatment method for an aluminum alloy and a casing made of an aluminum alloy.

Aluminum alloys are currently widely used in aerospace, aerospace, automotive and microelectronics industries. However, the standard electrode potential of aluminum alloy is very low, and the corrosion resistance is poor. Exposure to the natural environment causes rapid surface corrosion.

A method of improving the corrosion resistance of an aluminum alloy is usually to form a protective coating on the surface thereof. Conventional anodizing, electrodeposition, chemical conversion film technology and surface treatment methods of aluminum alloys such as electroplating have the disadvantages of complicated production process, low efficiency and serious environmental pollution.

Vacuum coating (PVD) is a clean film forming technique. However, since the standard electrode potential of the aluminum alloy is very low, and the PVD coating itself inevitably has minute pores, the PVD coating formed on the surface of the aluminum alloy is prone to electrochemical corrosion, resulting in corrosion resistance of the PVD coating. The performance is reduced, and the improvement of the corrosion resistance of the aluminum alloy is limited.

In view of this, a surface treatment method capable of effectively improving the corrosion resistance of an aluminum alloy is provided.

Further, a casing made of the above aluminum alloy is also provided.

A surface treatment method for an aluminum alloy, comprising the steps of:

Providing an aluminum alloy substrate;

Magnetron sputtering an aluminum layer on the surface of the aluminum alloy substrate;

Oxygen ions are implanted into the aluminum layer to form an ion-implanted film mainly containing Al ₂ O ₃ and AlO solid solution phases.

A casing made of an aluminum alloy, the casing comprising an aluminum alloy substrate, an aluminum layer sequentially formed on a surface of the aluminum alloy substrate, and an ion implantation film, wherein the ion implantation film mainly contains Al ₂ O ₃ and AlO solid solution phase.

The surface treatment method of the aluminum alloy of the present invention is formed by magnetron sputtering on an aluminum alloy substrate to form an aluminum layer, and an ion implantation film is formed on the aluminum layer. The composite film layer composed of the aluminum layer and the ion implantation film remarkably improves the corrosion resistance of the aluminum alloy substrate, and the surface treatment process is simple and has almost no environmental pollution.

Referring to FIG. 1 and FIG. 2 simultaneously, a surface treatment method for an aluminum alloy according to a preferred embodiment of the present invention includes the following steps:

S101: An aluminum alloy substrate 11 is provided.

The aluminum alloy base 11 can be obtained by press molding.

S102: pretreating the aluminum alloy substrate 11. The pre-processing includes:

The aluminum alloy substrate 11 is subjected to a polishing treatment to remove an oxide film on the surface of the aluminum alloy substrate 11. The surface roughness Rz of the aluminum alloy substrate 11 after polishing was < 1.2 μm.

The polished aluminum alloy substrate 11 is sequentially placed in deionized water and acetone having a purity greater than 99.9% for ultrasonic cleaning to remove oil stains on the surface. After the cleaning, the aluminum alloy substrate 11 is dried for use.

S103: Magnetron sputtering is performed on the surface of the aluminum alloy substrate 11 to form an aluminum layer 13.

The specific operation method and process parameters for forming the aluminum layer 13 are: placing the aluminum alloy substrate 11 in a vacuum chamber of a vacuum coating machine (not shown), and evacuating to a vacuum of 8.0×10 ^-3 to 5.0×10 ^{- 2} Pa, applying a bias voltage of -50 to -300 V on the aluminum alloy substrate 11, heating the vacuum chamber to 50 to 180 ° C (ie, a sputtering temperature of 50 to 180 ° C), and a flow rate of 100 to 300 sccm (standard state) Argon gas (working gas) in milliliters per minute, the power source of the aluminum target installed in the vacuum chamber of the coater is turned on, and the aluminum layer 13 is deposited. The time for depositing the aluminum layer 13 is 30 to 90 minutes. Among them, the purity of argon gas is 99.999%.

The vacuum coating machine can be used for surface treatment such as multi-arc ion plating, ion implantation and plasma cleaning, in addition to magnetron sputtering coating treatment.

Since the electrode potential of aluminum is equivalent to that of the aluminum alloy, galvanic corrosion is less likely to occur between the aluminum layer 13 and the aluminum alloy substrate 11; in addition, the formation of the aluminum layer 13 can also prevent the aluminum alloy substrate 11 from directly contacting the corrosive medium. The second phase corrosion occurs, and therefore, the formation of the aluminum layer 13 can significantly improve the corrosion resistance of the aluminum alloy substrate 11.

The second phase corrosion is: when the aluminum alloy is directly in the corrosive medium, the impurities other than the aluminum phase in the aluminum alloy are equal, and the potential difference between the second phase particles and the aluminum phase is likely to occur and local electrochemical corrosion occurs. .

S104: Oxygen ions are implanted into the surface of the aluminum layer 13 by an ion implantation process to form an ion implantation film 15.

The oxygen ion implantation process is: placing an aluminum alloy substrate 11 coated with an aluminum layer 13 in a vacuum chamber of the vacuum coating machine, the ion source of the vacuum coating machine ionizing oxygen and accelerating by a high voltage electric field. An ion beam having tens of thousands or even millions of electron volts of energy is incident on the surface of the aluminum layer 13 to undergo a series of physical and chemical reactions with atoms or molecules in the surface layer of the aluminum layer 13 and finally on the aluminum layer 13 The surface deposition forms an ion implantation film 15 mainly containing Al ₂ O ₃ and AlO solid solution phases. Since the oxidized volume ratio coefficient of the metal aluminum is greater than 1, the formed Al ₂ O ₃ makes the ion implantation film 15 have better compactness, and it is difficult for the corrosive substance to enter the surface of the aluminum alloy substrate 11 via the ion implantation film 15, so that The corrosion resistance of the aluminum alloy base 11 is enhanced.

The parameters for injecting the oxygen ions in the embodiment are: vacuum degree of the vacuum chamber is 3.0×10 ^-8 Pa, oxygen purity is 99.99%, ion source power is 0.5~5kw, working pressure is 0.8~8.0Pa, injection time It is 30~120min.

It can be understood that the surface treatment method of the above aluminum alloy base 11 may further include a step of plasma cleaning the aluminum alloy base 11 in the coating machine before forming the aluminum layer 13.

Referring to FIG. 2, a casing 10 made of the surface-treated aluminum alloy base 11 includes an aluminum alloy base 11, an aluminum layer 13 and an ion implantation film 15 which are sequentially formed on the aluminum alloy base 11.

The aluminum layer 13 may have a thickness of 0.5 to 1.0 μm.

The ion implantation membrane 15 mainly contains Al ₂ O ₃ and an AlO solid solution phase.

In the surface treatment method of the aluminum alloy according to the preferred embodiment of the present invention, the aluminum layer 13 is formed by magnetron sputtering on the aluminum alloy substrate 11, and the ion implantation film 15 is formed on the aluminum layer 13. The formation of the ion implantation film 15 remarkably improves the corrosion resistance of the casing 10, thereby providing better corrosion resistance protection to the casing 10.

10. . . case

11. . . Aluminum alloy substrate

13. . . Aluminum layer

15. . . Ion implantation membrane

1 is a flow chart of a method for treating an aluminum alloy surface according to a preferred embodiment of the present invention;

2 is a cross-sectional view of a housing in accordance with a preferred embodiment of the present invention.

10. . . case

11. . . Aluminum alloy substrate

13. . . Aluminum layer

15. . . Ion implantation membrane

Claims (10)

A surface treatment method for an aluminum alloy, comprising the steps of:
Providing an aluminum alloy substrate;
Magnetron sputtering an aluminum layer on the surface of the aluminum alloy substrate;
Oxygen ions are implanted into the aluminum layer to form an ion-implanted film mainly containing Al ₂ O ₃ and AlO solid solution phases. The surface treatment method of the aluminum alloy according to claim 1, wherein the step of magnetron sputtering the aluminum layer is performed in the following manner: applying an aluminum target as a target and applying -50 to the aluminum alloy substrate The bias voltage of 300V is argon gas as the working gas, the flow rate is 100~300sccm, the sputtering temperature is 50~180°C, and the sputtering time is 20~90min. The surface treatment method of the aluminum alloy according to claim 1, wherein the step of forming the ion implantation membrane is performed in a vacuum chamber of a vacuum coating machine, and the vacuum degree of the vacuum chamber is 3.0×10 ^-8 Pa, ion source ion source power is 0.5~5kw, working pressure is 0.8~8.0Pa, and injection time is 30~120min. The surface treatment method for an aluminum alloy according to claim 1, wherein the surface treatment method further comprises the step of polishing and ultrasonically cleaning the aluminum alloy substrate before performing magnetron sputtering. The surface treatment method of the aluminum alloy according to Item 4, wherein the polished aluminum alloy substrate has a surface roughness Rz < 1.2 μm. The surface treatment method of the aluminum alloy according to claim 1, wherein the surface treatment method further comprises the step of plasma-cleaning the aluminum alloy substrate before forming the aluminum layer. A casing made of an aluminum alloy, the casing comprising an aluminum alloy base, the improvement comprising: the casing further comprising an aluminum layer and an ion implantation film sequentially formed on a surface of the aluminum alloy substrate, wherein the ion implantation film is mainly Contains Al ₂ O ₃ and AlO solid solution phase. The casing of claim 7, wherein the aluminum layer has a thickness of 0.5 to 1.0 μm. The casing of claim 7 or 8, wherein the aluminum layer is formed by magnetron sputtering. The casing according to claim 7, wherein the ion implantation membrane is formed by injecting oxygen ions onto the aluminum layer.