TWI471430B - Anticorrosion surface treating for al alloy and articles treated by the same - Google Patents

Description

Aluminum alloy surface anti-corrosion treatment method and product thereof

The invention relates to an anticorrosive treatment method for aluminum alloy surface and a product thereof.

Aluminum alloy has the advantages of light weight and good heat dissipation performance, and is widely used in communications, electronics, transportation, construction and aerospace. An aluminum oxide protective film is formed on the surface of the aluminum alloy in the air. Under normal atmospheric conditions, the aluminum oxide film on the surface of the aluminum alloy can effectively protect the aluminum alloy substrate, and in the moisture containing the electrolyte, for example, the atmospheric environment of the ocean surface. The surface of the aluminum alloy is prone to pitting corrosion, which seriously damages the appearance of the aluminum alloy product and leads to shortened service life of the product.

Salt spray resistance is an important parameter of the corrosion resistance of aluminum alloy. In order to improve the salt spray resistance of aluminum alloy, it is usually necessary to carry out surface film formation on the surface of aluminum alloy. Common treatment methods include anodizing, baking varnish, etc. However, these processes all have large environmental pollution problems. The vacuum coating (PVD) technology is a very environmentally friendly coating process, and the type of coating that can be plated is excellent, and the wear resistance is excellent. However, the film deposited by the PVD process tends to grow in the form of columnar crystals, so the film layer exists. A large amount of intercrystalline gaps result in insufficient film densification and cannot effectively prevent salt spray erosion.

In view of this, it is necessary to provide an aluminum alloy surface anticorrosive treatment method which can effectively improve the salt spray resistance of the aluminum alloy.

In addition, it is also necessary to provide an aluminum alloy article obtained by the above method.

An aluminum alloy surface anti-corrosion treatment method comprises the following steps:

(1) ultrasonic cleaning of the aluminum alloy substrate with anhydrous ethanol;

(2) Using pure aluminum as the target, argon gas as working gas, nitrogen gas and oxygen as reaction gas, magnetron sputtering method is used to sputter an aluminum oxynitride film on the surface of the aluminum alloy substrate, the oxygen flow rate is 15 ~70sccm, nitrogen flow rate is 10~60sccm.

An aluminum alloy product treated by the above method, comprising an aluminum alloy substrate and an aluminum oxynitride film formed on the surface of the aluminum alloy substrate, wherein the aluminum atomic oxide film has a percentage of aluminum atoms of 50% to 80%, The percentage of oxygen atoms is 15% to 40%, and the percentage of nitrogen atoms is 5% to 10%.

Compared with the prior art, the aluminum alloy article prepared by the above-mentioned aluminum alloy surface anti-corrosion treatment method has an aluminum oxynitride film formed on the surface thereof, and the oxynitride film is composed of relatively fine crystal grains, and the intergranular gap is compared. Small, making the aluminum oxynitride film relatively dense, can effectively prevent salt spray erosion, so it can effectively improve the corrosion resistance of aluminum alloy.

The method for preserving the surface of the aluminum alloy of the invention mainly comprises the following steps:

(1) Ultrasonic cleaning of the aluminum alloy substrate with anhydrous ethanol to remove oil stain on the surface of the sample.

(2) Using pure aluminum as the target, argon gas as the working gas, nitrogen and oxygen as the reaction gas, and the surface of the cleaned aluminum alloy substrate is coated with aluminum oxynitride (Al-ON) by magnetron sputtering. film. The sputtering parameters are as follows: the vacuum degree in the vacuum chamber is 5×10 ^-3 Pa~9×10 ^-3 Pa, the cavity temperature is 100-180 ° C, the rotating speed is 0.5~1 rpm, and the argon flow rate is 150. ~300sccm (standard state ML/min), oxygen flow rate is 15~70sccm, nitrogen flow rate is 10~60sccm, aluminum target power is 6~12kw, bias voltage is -100~-300V, duty cycle is 40%~60% Sputtered for 0.5 to 4 hours. Thus, the aluminum oxynitride film having a thickness of about 0.2 to 1.5 μm is obtained on the surface of the aluminum alloy substrate.

The aluminum alloy article obtained by the above aluminum alloy surface anticorrosive treatment method comprises an aluminum alloy substrate and an aluminum oxynitride film formed on the surface of the aluminum alloy substrate, wherein the aluminum oxynitride film has a percentage of aluminum atoms of 50% ~80%, the percentage of oxygen atoms is 15%~40%, and the percentage of nitrogen atoms is 5%~10%. The oxynitride film is composed of crystal grains having a diameter of about 6 to 10 nm.

The invention will now be specifically described by way of examples.

Example 1

The aluminum alloy sample was ultrasonically cleaned with absolute ethanol for about 30 minutes. The cleaned aluminum alloy sample is placed in a vacuum chamber of an intermediate frequency magnetron sputtering coating machine. The intermediate frequency magnetron sputtering coating machine used in this embodiment is produced by Shenzhen Nanfang Innovation Vacuum Technology Co., Ltd., and the model number is SM-1100H.

Turn on the vacuum pump to evacuate the vacuum chamber and set the vacuum to 8×10 ^-3 Pa. Turn on the turret and set the rotation speed to 0.5 rpm. Turn on the vacuum chamber and set the chamber temperature to 120 °C.

After the vacuum of the vacuum chamber is pumped to the above set value, the working gas argon gas and the reaction gas oxygen and nitrogen are introduced, the flow rate of the argon gas is 150 sccm (standard state cc/min), the oxygen flow rate is 20 sccm, and the nitrogen flow rate is 15 sccm; The aluminum target was adjusted to have an aluminum target power of 8 kw, a bias voltage of -200 V, a duty ratio of 50%, and sputtering for 1 hour, thereby obtaining an aluminum oxynitride film on the surface of the aluminum alloy.

Example 2

Example 2 is similar to Example 1, except that the oxygen flow rate of this embodiment was 40 sccm, and the nitrogen flow rate was 30 sccm, and other conditions were the same as in Example 1. An aluminum alloy article having an aluminum oxynitride film formed on the surface thereof was also obtained in accordance with Example 2.

The aluminum oxynitride films of the aluminum alloy articles prepared in Example 1 and Example 2 were similar in morphology and structure, and had similar anticorrosive properties.

Comparative example

The aluminum alloy sample was sputtered by the same intermediate frequency magnetron sputtering coater as in Example 1. The reaction gas different from Example 1 was only nitrogen gas, and the flow rate of nitrogen gas was 40 sccm. Other conditions were the same as in Example 1. A single component aluminum nitride (AlN) film was sputtered on the surface of the aluminum alloy sample.

The surface morphology of the aluminum oxynitride film and the aluminum nitride (AlN) film plated in the first example were observed by scanning electron microscopy. The scanning electron microscope used in the model was JSM-6701F. Field emission scanning electron microscope. 1 is a scanning electron micrograph of a comparatively plated aluminum nitride (AlN) film, and FIG. 2 and FIG. 3 are scanning electron micrographs of an aluminum oxynitride film deposited in Example 1 of the present invention. It can be seen from the figure that the one-component aluminum nitride (AlN) film is composed of relatively coarse grains, and a large amount of intergranular gap exists on the surface, and the aluminum oxynitride film is composed of relatively fine crystal grains, intergranular gap. It is relatively small, making the aluminum oxynitride film relatively dense.

The aluminum alloy sample coated with the aluminum oxynitride film prepared by the method of the embodiment of the present invention and the aluminum alloy sample coated with the aluminum nitride (AlN) film prepared in the comparative example were subjected to a 35 ° C neutral salt. Fog (NaCl concentration of 5%) was tested. As a result, it was found that the aluminum alloy sample of the surface-plated aluminum nitride (AlN) film prepared in the comparative example was significantly corroded after 24 hours; and the surface-coated aluminum oxynitride film prepared by the method of the present invention was obtained. The aluminum alloy samples showed corrosion after 72 hours.

It can be seen that the aluminum alloy product prepared by the aluminum alloy surface anti-corrosion treatment method of the embodiment of the present invention has an aluminum oxynitride film on the surface thereof, and the aluminum oxynitride film can effectively prevent salt spray erosion, thereby improving the resistance of the aluminum alloy. Corrosion performance.

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FIG. 1 is a scanning electron micrograph of an 50,000-fold magnification of an aluminum nitride film prepared by magnetron sputtering.

2 is a scanning electron micrograph of an 50,000-fold magnification of an aluminum oxynitride film prepared according to an embodiment of the present invention.

Fig. 3 is a scanning electron micrograph of the aluminum oxynitride film shown in Fig. 2 magnified 100,000 times.

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Claims (9)

An aluminum alloy surface anti-corrosion treatment method comprises the following steps:
(1) ultrasonic cleaning of the aluminum alloy substrate with anhydrous ethanol;
(2) Using pure aluminum as the target, argon gas as working gas, nitrogen gas and oxygen as reaction gas, magnetron sputtering method is used to sputter an aluminum oxynitride film on the surface of the aluminum alloy substrate, the oxygen flow rate is 15 ~70sccm, nitrogen flow rate is 10~60sccm. The method for preserving the surface treatment of an aluminum alloy according to claim 1, wherein the step (2) is performed under the following parameter conditions: the vacuum degree in the vacuum chamber is 5×10 ^-3 Pa~9×10 ^-3 Pa, the cavity temperature is 100~180°C, the rotating speed is 0.5~1 rev/min, the aluminum target power is 6~12kw, the argon flow rate is 150~300sccm, and the aluminum target bias is -100~-300V, accounting for The space ratio is 40% to 60%, and sputtering is 0.5 to 4 hours. The method for preserving an aluminum alloy surface according to claim 2, wherein the step (2) is performed in an intermediate frequency magnetron sputtering apparatus. The method for preserving an aluminum alloy surface according to claim 2, wherein the aluminum oxynitride film has a thickness of 0.2 to 1.5 μm. The method for preserving the surface of an aluminum alloy according to claim 1, wherein the aluminum oxynitride film has a percentage of aluminum atoms of 50% to 80%, and the number of oxygen atoms is 15% to 40%, nitrogen. The percentage of atoms is 5% to 10%. The method for preserving an aluminum alloy surface according to claim 1, wherein the aluminum oxynitride film is composed of crystal grains having a diameter of 6 to 10 nm. An aluminum alloy article comprising an aluminum alloy substrate, the improvement comprising: the aluminum alloy article further comprising an aluminum oxynitride film formed on the surface of the aluminum alloy substrate, wherein the aluminum oxynitride film has a percentage of aluminum atoms of 50 %~80%, the percentage of oxygen atoms is 15%~40%, and the percentage of nitrogen atoms is 5%~10%. The aluminum alloy article according to claim 7, wherein the aluminum oxynitride film is composed of crystal grains having a diameter of 6 to 10 nm. The aluminum alloy article according to claim 7, wherein the aluminum oxynitride film has a thickness of 0.2 to 1.5 μm.