阅读说明：本技术 一种防腐铝型材的制备方法 (Preparation method of anticorrosive aluminum profile ) 是由 廖健 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种防腐铝型材的制备方法,它包括以下步骤：S1、脱脂；S2、碱洗；S3、中和；S4、阳极氧化；S5、钝化处理：将铝合金型材浸入到盛装有浓度为0.2~0.3g/L的氟化钠、0.4~0.6g/L氢氟酸铵、0.1~0.15g/L高锰酸钾、0.1~0.13g/L硝酸盐和0.2~0.3g/L氯化镨的化学处理液中,在浸泡过程中,阳极氧化膜的表面上形成保护层,当浸泡20~30min后,将铝合金型材取出,取出后用清水；S7、喷涂处理：向铝合金型材表面喷涂由21~35份聚偏氟乙烯、80~90份二甲基乙酰胺、13~18份NaH<Sub>2</Sub>PO<Sub>4</Sub>、5~10份二氧化钛、10~12份色素组成的原料,喷涂时间1.0~2.0min,喷淋压力为0.05~0.07MPa,从而在保护层表面上形成一层防腐涂层。本发明的有益效果是：耐腐蚀效果更好、附着力更强；生产制备过程中不会产生对人体、环境有害的有毒物质、不污染环境。(The invention discloses a preparation method of an anticorrosive aluminum profile, which comprises the following steps of S1 degreasing, S2 alkali washing, S3 neutralizing, S4 anodizing, S5 passivating, wherein the aluminum profile is immersed into a chemical treatment solution containing 0.2 ~ 0.3.3 g/L of sodium fluoride, 0.4 ~ 0.6.6 g/L of ammonium hydrofluoride, 0.1 ~ 0.15g/L of potassium permanganate, 0.1 ~ 0.13.13 g/L of nitrate and 0.2 ~ 0.3.3 g/L of praseodymium chloride, a protective layer is formed on the surface of an anodic oxidation film in the immersion process, and after the aluminum profile is immersed for 20 ~ 30min, the aluminum profile is taken outTaking out, using clear water, S7, spraying 21 ~ 35 parts of polyvinylidene fluoride, 80 ~ 90 parts of dimethylacetamide and 13 ~ 18 parts of NaH on the surface of the aluminum alloy section 2 PO 4 The coating comprises raw materials of 5 ~ 10 parts of titanium dioxide and 10 ~ 12 parts of pigment, wherein the spraying time is 1.0 ~ 2.0.0 min, and the spraying pressure is 0.05 ~ 0.07.07 MPa, so that an anticorrosive coating is formed on the surface of the protective layer.)

1. The preparation method of the anticorrosive aluminum profile is characterized by comprising the following steps: it comprises the following steps:

s1, degreasing, namely soaking the aluminum alloy workpiece in a degreasing solution containing 5 ~ 15 mass percent of sulfuric acid and 2 ~ 5g/L of emulsifier for 4 ~ 6min at the temperature of 50 ~ 55 ℃;

s2, alkali washing, namely soaking the degreased aluminum alloy section into alkali liquor with the sodium hydroxide concentration of 50 ~ 150g/L and the temperature of 50 ~ 60 ℃ for 5 ~ 60S, so that oxides and dirt naturally formed on the surface of the aluminum alloy section can be removed;

s3, neutralizing, namely soaking the aluminum alloy section in a nitric acid solution with the concentration of 10 ~ 15% for 20 ~ 30S at normal temperature, and performing neutralization reaction on the nitric acid solution and a sodium hydroxide solution;

s4, anodizing, namely anodizing by using sulfuric acid solution with the concentration of 180 ~ 200g/L as electrolyte to form an anodized film on the surface of the aluminum alloy profile at the temperature of 18 ~ 20 ℃ and the voltage of 14V, wherein the aluminum content is 1 ~ 15g/L, and the oxidizing time is 30 ~ 40 min;

s5, passivating, namely immersing the aluminum alloy section into chemical treatment liquid containing 0.2 ~ 0.3.3 g/L of sodium fluoride, 0.4 ~ 0.6.6 g/L of ammonium hydrofluoride, 0.1 ~ 0.15.15 g/L of potassium permanganate, 0.1 ~ 0.13.13 g/L of nitrate and 0.2 ~ 0.3.3 g/L of praseodymium chloride, forming a protective layer on the surface of an anodic oxide film in the immersion process, taking out the aluminum alloy section after 20 ~ 30min of immersion, and using clear water after taking out;

s6, drying, namely conveying the aluminum alloy section into a drying oven, and drying the aluminum alloy section for 30 ~ 40min at the temperature of 40 ~ 60 ℃;

s7, spraying, namely spraying 21 ~ 35 parts of polyvinylidene fluoride, 80 ~ 90 parts of dimethylacetamide and 13 ~ 18 parts of NaH on the surface of the aluminum alloy profile₂PO₄5 ~ 10 parts of titanium dioxide and 10 ~ 12 parts of pigment, wherein the spraying time is 1.0 ~ 2.0.0 min, and the spraying pressure is 0.05 ~ 0.07.07 MPa, so that an anticorrosive coating is formed on the surface of the protective layer.

2. The preparation method of the anticorrosive aluminum profile according to claim 1, characterized in that: and after the step S7 is finished, curing the anticorrosive coating.

3. The preparation method of the anticorrosive aluminum profile according to claim 2, characterized in that: and after the solidification is finished, detecting whether the anticorrosive coating has the phenomenon of falling off or cracking, and if the anticorrosive coating is detected to be qualified, conveying the finished aluminum alloy section to a packaging process.

Technical Field

The invention relates to a preparation method of an anticorrosive aluminum profile.

Background

The corrosion resistance is one of the important properties of the aluminum profile. Generally, the basic corrosion types of aluminum profiles are point corrosion, galvanic corrosion, crevice corrosion, intergranular corrosion, filiform corrosion, and the like.

The pitting corrosion is also called as hole corrosion, and is a very local corrosion form of pinpoint, point and hole on metal. Pitting of aluminium occurs in atmospheric, fresh water and neutral aqueous solutions and can also lead to severe perforation, although the corrosion pores may eventually stop developing and the amount of corrosion remains at a limit. Pitting corrosion is a unique form of anodic reaction and is an autocatalytic process.

Galvanic corrosion is a characteristic corrosion form of aluminum, the natural potential of which is very negative, and when aluminum comes into contact with other metals, it is always at the anode to accelerate its corrosion. Galvanic corrosion, also known as bimetallic corrosion, is determined by the relative position of the two metal potential sequences.

Crevice corrosion is due to the differentially pumped cell effect, resulting in accelerated corrosion within the crevice, while no effect outside the crevice. Crevice corrosion is not very dependent on the type of alloy, and crevice corrosion can occur with even very corrosion resistant alloys. In recent years, the mechanism of crevice corrosion has been studied more deeply, and the acidic environment at the top of crevice is the motive force for corrosion.

The intergranular corrosion means that pure aluminum does not cause the excessive intergranular corrosion, the reason of the intergranular corrosion is irrelevant to heat treatment, and alloying elements or intermetallic compounds are precipitated and separated along grain boundaries and form a corrosion battery relative to the grains which are anodes, so that the intergranular corrosion is accelerated.

Filiform corrosion is a sub-membranous corrosion that develops below the membrane in a vermicular pattern. Filiform corrosion is related to the alloy composition, pre-treatment before coating of the aluminium profile and environmental factors (humidity, temperature, chlorides, etc.).

In chinese patent publication No. CN 108149250 a, a method for preparing a bright anticorrosive aluminum profile is disclosed, which comprises the following steps: (1) preparing a bright preservative solution: preparing 20-40 parts of sodium fluoride, 30-60 parts of ammonium bifluoride, 10-20 parts of potassium permanganate, 40-50 parts of potassium chromate, 15-25 parts of zinc phosphate, 8-18 parts of sodium nitrate, 5-12 parts of praseodymium chloride, 10-16 parts of ethylene diamine tetraacetic acid, 7-14 parts of malic acid, 8-12 parts of sodium dodecyl benzene sulfate, 6-13 parts of nickel sulfate, 15-25 parts of triethanolamine and 900 parts of water by weight; controlling the pH value to be 3-4 to obtain a bright preservative solution; (2) first dipping treatment: heating the bright anticorrosive liquid to 30-40 ℃, and then soaking the aluminum profile in the bright anticorrosive liquid for 2-4 min; (3) primary drying: carrying out hot air circulation drying on the aluminum profile subjected to the first dipping treatment for 40-50min at the temperature of 80-95 ℃; (4) and (3) second impregnation treatment: performing secondary impregnation under the microwave vacuum condition, specifically vacuumizing to the vacuum degree of-0.02 MPa-0.001 MPa, performing microwave treatment with the microwave frequency of 100MHz and 230MHz, and performing microwave treatment on the aluminum profile subjected to primary drying in the bright preservative subjected to primary impregnation for 37 s; (5) and (3) washing and drying for the second time: washing with running water until the pH value of eluate is neutral, and drying at 40-48 deg.C. Although this process can produce an anticorrosive aluminum profile, corrosion is prevented only by a single oxide film, and corrosion still occurs after long-term use. In addition, in the production and preparation process, the praseodymium chloride and the ammonium bifluoride used cause harm to human bodies and pollution to the environment.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the corrosion-resistant paint which has better corrosion resistance and stronger adhesive force; the preparation method of the anti-corrosion aluminum profile does not generate toxic substances harmful to human bodies and the environment and does not pollute the environment in the production and preparation process.

The purpose of the invention is realized by the following technical scheme: the preparation method of the anticorrosive aluminum profile comprises the following steps:

s1, degreasing, namely soaking the aluminum alloy workpiece in a degreasing solution containing 5 ~ 15 mass percent of sulfuric acid and 2 ~ 5g/L of emulsifier for 4 ~ 6min at the temperature of 50 ~ 55 ℃;

s2, alkali washing, namely soaking the degreased aluminum alloy section into alkali liquor with the sodium hydroxide concentration of 50 ~ 150g/L and the temperature of 50 ~ 60 ℃ for 5 ~ 60S, so that oxides and dirt naturally formed on the surface of the aluminum alloy section can be removed;

s3, neutralizing, namely soaking the aluminum alloy section in a nitric acid solution with the concentration of 10 ~ 15% for 20 ~ 30S at normal temperature, and performing neutralization reaction on the nitric acid solution and a sodium hydroxide solution;

s4, anodizing, namely anodizing by using sulfuric acid solution with the concentration of 180 ~ 200g/L as electrolyte to form an anodized film on the surface of the aluminum alloy profile at the temperature of 18 ~ 20 ℃ and the voltage of 14V, wherein the aluminum content is 1 ~ 15g/L, and the oxidizing time is 30 ~ 40 min;

s5, passivating, namely immersing the aluminum alloy section into chemical treatment liquid containing 0.2 ~ 0.3.3 g/L of sodium fluoride, 0.4 ~ 0.6.6 g/L of ammonium hydrofluoride, 0.1 ~ 0.15.15 g/L of potassium permanganate, 0.1 ~ 0.13.13 g/L of nitrate and 0.2 ~ 0.3.3 g/L of praseodymium chloride, forming a protective layer on the surface of an anodic oxide film in the immersion process, taking out the aluminum alloy section after 20 ~ 30min of immersion, and using clear water after taking out;

s6, drying, namely conveying the aluminum alloy section into a drying oven, and drying the aluminum alloy section for 30 ~ 40min at the temperature of 40 ~ 60 ℃;

s7, spraying, namely spraying 21 ~ 35 parts of polyvinylidene fluoride, 80 ~ 90 parts of dimethylacetamide and 13 ~ 18 parts of NaH on the surface of the aluminum alloy profile₂PO₄5 ~ 10 parts of titanium dioxide and 10 ~ 12 parts of pigment, wherein the spraying time is 1.0 ~ 2.0.0 min, and the spraying pressure is 0.05 ~ 0.07.07 MPa, so that an anticorrosive coating is formed on the surface of the protective layer;

and after the step S7 is finished, curing the anticorrosive coating.

And after the solidification is finished, detecting whether the anticorrosive coating has the phenomenon of falling off or cracking, and if the anticorrosive coating is detected to be qualified, conveying the finished aluminum alloy section to a packaging process.

The invention has the following advantages: the invention prepares a layer of film on the surface, and effectively protects the aluminum alloy by utilizing the barrier formed by the film between the aluminum alloy matrix and the external environment, thereby expanding the application range of the aluminum alloy. According to the invention, the anodic oxide film, the protective layer and the anticorrosive coating with anticorrosion are respectively formed on the outer surface of the aluminum alloy, compared with the traditional method of corrosion prevention through a single oxide film, the corrosion-resistant effect is better, the anticorrosive coating is prepared in a spraying manner, the adhesion of the anodic oxide film, the protective layer and the anticorrosive coating is stronger, and the mechanical property of the aluminum alloy section is improved. In addition, the process does not generate toxic substances harmful to human bodies and the environment and does not pollute the environment in the production and preparation process.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The invention will be further described with reference to the accompanying drawings, without limiting the scope of the invention to the following: