阅读说明：本技术 铝合金表面涂装前的表面处理方法 (Surface treatment method before aluminum alloy surface coating ) 是由 马新民 孙文进 李红艳 孟凡霸 张文娟 苏文园 韩亚飞 李沛 周旭 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种铝合金表面涂装前的表面处理方法,包括：使用硬毛刷蘸着pH值为9～11的碱液刷洗铝合金表面的待涂装表面；将刷洗过碱液的铝合金表面静置8～10分钟；使用硬毛刷刷洗表面,待铝合金表面出现铝金属光泽后,使用冲洗液冲洗铝合金表面,并将冲洗液经收集口排出；测试冲洗液的pH值,直至pH值为7,停止冲洗；使用压缩空气吹干铝合金表面的残留水分。本发明的方法采用碱液与铝合金表面的表面氧化物进行化学反应,达到去除表面氧化物的目的,通过碱和铝的反应,达到增加表面粗糙度的目的,彻底解决了现有技术中铝合金表面涂装前喷砂或打磨处理所存在的粉尘污染问题。(The invention discloses a surface treatment method before aluminum alloy surface coating, which comprises the following steps: dipping alkali liquor with the pH value of 9-11 in a scrubbing brush to scrub the surface to be coated of the aluminum alloy surface; standing the aluminum alloy surface brushed with the alkali liquor for 8-10 minutes; scrubbing the surface by using a hard brush, flushing the surface of the aluminum alloy by using flushing liquid after the surface of the aluminum alloy has aluminum metal luster, and discharging the flushing liquid through a collecting port; testing the pH value of the flushing liquid until the pH value is 7, and stopping flushing; and blowing the residual moisture on the surface of the aluminum alloy by using compressed air. The method of the invention adopts alkali liquor to carry out chemical reaction with the surface oxide on the surface of the aluminum alloy, thus achieving the purpose of removing the surface oxide, achieving the purpose of increasing the surface roughness through the reaction of alkali and aluminum, and thoroughly solving the problem of dust pollution existing in sand blasting or polishing treatment before the surface of the aluminum alloy is coated in the prior art.)

1. A surface treatment method before aluminum alloy surface coating, which adopts alkali liquor to carry out chemical reaction with surface oxides of the aluminum alloy surface to remove the surface oxides and increases the surface roughness by the reaction of the alkali and aluminum, and is characterized by comprising the following steps:

(1) brushing the surface to be coated of the aluminum alloy surface by using a hard brush dipped with alkali liquor with the pH value of 9-11 until the surface to be coated is covered by the alkali liquor;

(2) standing the aluminum alloy surface brushed with the alkali liquor for 8-10 minutes to enable the alkali liquor to react with the aluminum alloy surface;

(3) scrubbing the surface by using a hard brush to facilitate the reaction, thoroughly flushing the surface of the aluminum alloy by using flushing liquid after the surface of the aluminum alloy has aluminum metal luster, and discharging the flushing liquid through a collecting port;

(4) testing the pH value of the washing liquid until the pH value is 7, and stopping washing;

(5) and blowing the residual moisture on the surface of the aluminum alloy by using compressed air.

2. The method for surface treatment of an aluminum alloy before surface coating according to claim 1, wherein the alkali solution is a NaOH solution.

3. The method for surface treatment of an aluminum alloy before surface coating according to claim 1, wherein the pH of the alkaline solution is 10.

4. The method for surface treatment before surface coating of an aluminum alloy according to claim 1, wherein the rinse solution is fresh water.

5. The method for surface treatment before surface coating of an aluminum alloy according to claim 1, wherein the rinsing liquid is tap water.

6. The surface treatment method before aluminum alloy surface coating according to any one of claims 1 to 5, characterized in that the aluminum alloy surface painting operation is completed within 1 hour after drying the residual moisture of the aluminum alloy surface with compressed air.

Technical Field

The invention belongs to the technical field of metal surface treatment, and particularly relates to a surface treatment method before aluminum alloy surface coating.

Background

Marine equipment, ships, offshore wind power equipment and other marine equipment all relate to the deck platform, before the deck platform officially commissioned for use, need to the deck platform surface coating paint to improve the corrosion resisting property of deck platform. With the improvement of the technological level, in recent years, aluminum alloy deck platforms gradually replace carbon steel deck platforms. The coating operation of the aluminum alloy deck platform is always carried out according to the mature operation process of a shipyard, namely the delivered ship paint is ensured to be bright and beautiful, and the whole ship paint can be renovated before ship delivery. Because the aluminum alloy deck platform has low surface oxide and surface roughness, the aluminum alloy deck platform is difficult to roughen paint, so that the aluminum alloy deck platform needs to be subjected to surface treatment before paint is coated to remove the surface oxide and improve the surface roughness.

In the prior art, surface treatment before coating of the surface of the aluminum alloy is generally carried out by sand blasting and polishing. However, the dust pollution caused by the direct sand blasting and grinding seriously deviates from the current environmental protection requirement. With the continuous improvement of environmental protection requirement, open-air sandblast is restricted with polishing strictly, and this has seriously hindered the normal clear of production, has increased the risk that can't in time deliver.

In order to reduce the environmental impact of the surface treatment operation before the aluminum alloy surface coating, there is a technology for removing the oxide on the aluminum alloy surface by using alkali liquor, for example, chinese patent application with patent publication No. CN108014985A, but the following unreasonable technical problems exist in the prior art: after removing oxides on the surface of the aluminum alloy by using alkali liquor, treating for 4-6 minutes by using acid liquor, wherein the reaction of acid and aluminum is severe and easy to lose control, so that excessive loss of the aluminum alloy is caused; in addition, the aluminum alloy neutralized by acid is put into an oven for drying and then is painted, but the temperature in the drying process is high, the aluminum alloy with the surface oxide removed in the drying process can generate new aluminum oxide on the surface of the aluminum alloy, and the aluminum oxide has negative influence on the bonding force of paint, so that the subsequent coating operation is not facilitated.

Disclosure of Invention

The invention aims to solve the problem of serious dust pollution existing in sand blasting or polishing treatment before aluminum alloy surface coating, and provides a surface treatment method before aluminum alloy surface coating, which comprises the following steps:

(1) brushing the surface to be coated of the aluminum alloy surface by using a hard brush dipped with alkali liquor with the pH value of 9-11 until the surface to be coated is covered by the alkali liquor;

(2) standing the aluminum alloy surface brushed with the alkali liquor for 8-10 minutes to enable the alkali liquor to react with the aluminum alloy surface;

(3) scrubbing the surface by using a hard brush to facilitate the reaction, thoroughly flushing the surface of the aluminum alloy by using flushing liquid after the surface of the aluminum alloy has aluminum metal luster, and discharging the flushing liquid through a collecting port;

(4) testing the pH value of the washing liquid until the pH value is 7, and stopping washing;

(5) and blowing the residual moisture on the surface of the aluminum alloy by using compressed air.

Preferably, in the surface treatment method before the surface coating of the aluminum alloy, the alkali solution is a NaOH solution.

Preferably, in the surface treatment method before the surface coating of the aluminum alloy, the pH of the alkali solution is 10.

Preferably, in the surface treatment method before the surface coating of the aluminum alloy, the rinse solution is fresh water.

Preferably, in the surface treatment method before the surface coating of the aluminum alloy, the rinse solution is tap water.

Preferably, in the surface treatment method before surface coating of the aluminum alloy described above, the painting operation of the surface of the aluminum alloy is completed within 1 hour after drying the residual moisture of the surface of the aluminum alloy with compressed air.

The surface treatment method before the surface coating of the aluminum alloy adopts the chemical reaction of the alkali liquor and the surface oxide of the surface of the aluminum alloy to achieve the aim of removing the surface oxide, simultaneously achieves the aim of increasing the surface roughness to improve the binding force of the paint and the surface of the aluminum alloy through the reaction of the alkali and the aluminum, has no dust pollution problem in the whole process, and thus thoroughly solves the problem of serious dust pollution existing in the sand blasting or polishing treatment before the surface coating of the aluminum alloy in the prior art.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments and examples of the present invention. It is apparent that the embodiments and examples described are only a part of the embodiments and examples of the present invention, and not all of the embodiments and examples. All other embodiments and examples, which can be obtained by a person skilled in the art without inventive step, are within the scope of protection of the present invention.

The surface treatment method before the surface coating of the aluminum alloy adopts alkali liquor to carry out chemical reaction with the surface oxide on the surface of the aluminum alloy so as to achieve the aim of removing the surface oxide, and the theoretical basis is as follows:

Al₂O₃+2NaOH＝2NaAlO₂+H₂O。

further, the surface treatment method before the surface coating of the aluminum alloy achieves the purpose of increasing the surface roughness to improve the bonding force between the paint and the surface of the aluminum alloy through the reaction of alkali and aluminum, and the theoretical basis is as follows:

2Al+2NaOH+2H₂O＝2NaAlO₂+3H₂↑。

specifically, the surface treatment method before the surface coating of the aluminum alloy comprises the following process steps:

(1) brushing the surface to be coated of the aluminum alloy surface by using a hard brush dipped with alkali liquor with the pH value of 9-11 until the surface to be coated is covered by the alkali liquor;

(2) standing the aluminum alloy surface brushed with the alkali liquor for 8-10 minutes to enable the alkali liquor to react with the aluminum alloy surface;

(3) scrubbing the surface by using a hard brush to facilitate the reaction, thoroughly flushing the surface of the aluminum alloy by using flushing liquid after the surface of the aluminum alloy has aluminum metal luster, and discharging the flushing liquid through a collecting port;

(4) testing the pH value of the washing liquid until the pH value is 7, and stopping washing;

(5) and the residual moisture on the surface of the aluminum alloy is thoroughly and quickly dried by using compressed air.

The surface of the aluminum alloy treated by the steps can be subjected to surface painting operation. Preferably, the surface painting operation is completed within 1 hour.

As a specific embodiment, the alkali liquor is NaOH solution.

As a specific embodiment, the pH of the lye is 10.

In one embodiment, the rinse solution is fresh water, such as tap water.

In the surface treatment method before the surface coating of the aluminum alloy, the reaction time is preferably controlled to be 8-10 minutes, and if the reaction time is too short, the reaction is not thorough, and the problem of incomplete oxide removal is easy to occur; if the time is too long, the aluminum alloy surface body is damaged.

The surface treatment method before the surface coating of the aluminum alloy adopts the alkali liquor to carry out chemical reaction with the surface oxide on the surface of the aluminum alloy, so as to achieve the purpose of removing the surface oxide, and simultaneously, through the reaction of the alkali and the aluminum, the purpose of increasing the surface roughness to improve the binding force between the paint and the surface of the aluminum alloy is achieved.

In addition, in the surface treatment method before the surface coating of the aluminum alloy, the alkali liquor can not only react with aluminum but also react with grease by saponification, so a special treatment step of removing the surface grease by using a degreasing agent is not needed.

In addition, in the surface treatment method before the aluminum alloy surface coating, the aluminum alloy surface is thoroughly washed by fresh water, and the pH value of the liquid on the aluminum alloy surface is controlled to be 7, so that acid liquor is not needed for neutralization, and the surface treatment process before the aluminum alloy surface coating is simplified.

Meanwhile, in the surface treatment method before the surface coating of the aluminum alloy, the residual moisture on the surface of the aluminum alloy is thoroughly and quickly dried by using compressed air, so that high-temperature drying is not needed, and the generation of new oxides on the surface of the aluminum alloy with the surface oxides removed in the drying process is avoided.

It should be noted that the above embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions.