CN106400079A - Preparation method of multiple super-hydrophobic composite film layers on aluminium alloy surface - Google Patents

Abstract

The invention discloses a method for preparing a multilayer super-hydrophobic composite film layer on the surface of an aluminum alloy. Firstly, the pretreated aluminum alloy sample is subjected to micro-arc oxidation treatment to obtain a porous micro-arc oxidation ceramic layer with a surface roughness of micron order. ; Place the obtained ceramic layer in a mixed solution for hydrothermal reaction, generate a hydrotalcite-like film on the surface of the ceramic layer and the inner wall of the hole, and construct a composite film layer with a micro/nano binary rough structure; The stearic acid modifies the composite film layer with low surface energy, and finally forms a multi-layer super-hydrophobic composite film layer on the surface of the aluminum alloy. Using this preparation method can solve the problem of expensive construction of micro/nano binary rough structure and pollute the environment, and provide a new technical means to construct micro/nano binary rough structure on the surface of aluminum alloy, thereby preparing a multilayer superhydrophobic Composite film layer.

Description

A kind of preparation method of multilayer superhydrophobic composite film layer on the surface of aluminum alloy

technical field

The invention relates to the technical field of aluminum alloys, in particular to a method for preparing a multilayer super-hydrophobic composite film on the surface of an aluminum alloy.

Background technique

At present, aluminum alloy has low density, high specific strength and specific stiffness, and is widely used in aerospace, transportation, electrical furniture and other fields, but its application is also limited due to its corrosion resistance. Surface treatment is carried out to improve its surface properties. Super-hydrophobic materials are widely used in daily life, industrial production and military affairs. Super-hydrophobic materials can reduce friction. For example, in the shipbuilding industry, if the surface of the ship's shell is super-hydrophobic, it can reduce the resistance of the ship to sail, thereby increasing its speed. And reduce fuel consumption. In addition, preparing a superhydrophobic film on the metal surface can improve the corrosion resistance of the metal material surface. If the metal frame on the outer surface of the building has superhydrophobicity, water droplets will not stay on the metal surface in rainy days or in a humid environment. Corrosion to metal surfaces is reduced, so superhydrophobic materials have broad application prospects.

There are many methods for preparing super-hydrophobic films in the prior art, but two factors must be considered: one is that the surface must have a micro/nano binary rough structure, and the other is that the surface material has low surface energy. Methods for constructing micro/nano binary rough structures generally include etching methods, such as chemical etching and plasma etching. However, one etching solution generally corresponds to one or a small number of substrates, and the generality of preparing rough surfaces by this method is not good; in addition, the template method is also used to construct micro/nano binary rough structures, but this method requires the fabrication of specific microstructures. The template of the structure, and then the specific microstructure is given to the target material by extrusion, pouring, etc., and the process is more complicated.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a multi-layer super-hydrophobic composite film on the surface of an aluminum alloy, which can solve the problems of expensive construction of a micro/nano binary rough structure and pollute the environment, and provide a new method in It is a technical means to construct micro/nano binary rough structure on the surface of aluminum alloy, so as to prepare multi-layer super-hydrophobic composite film.

A method for preparing a multilayer superhydrophobic composite film layer on the surface of an aluminum alloy, the preparation method comprising:

Step 1, first performing micro-arc oxidation treatment on the pretreated aluminum alloy sample to obtain a porous micro-arc oxidation ceramic layer with a surface roughness of micron level;

Step 2. Place the obtained ceramic layer in a mixed solution for hydrothermal reaction, generate a hydrotalcite-like film on the surface of the ceramic layer and the inner wall of the hole, and construct a composite film layer with a micro/nano binary rough structure ;

Step 3, using stearic acid to modify the composite film layer with low surface energy, and finally form a multi-layer super-hydrophobic composite film layer on the surface of the aluminum alloy.

In the step 1: the electrolytic solution used in the micro-arc oxidation treatment includes: sodium silicate of 5-20g/L, potassium hydroxide of 1-10g/L and glycerol of 1-10ml/L; And the temperature of the electrolyte is 20-25°C;

The DC pulse voltage used in the micro-arc oxidation treatment is 300-500V;

The obtained porous micro-arc oxidation ceramic layer has a surface roughness of 1-3 μm.

In the step 2: the mixed solution is prepared from metal sulfate and anhydrous sodium sulfate according to the ratio of 1:5; the pH value of the mixed solution is 5-7, wherein the metal sulfate The concentration is 0.05-0.3mol/L;

The temperature of the hydrothermal reaction is 50-100°C, and the reaction time is 2-48h;

The surface roughness of the obtained composite film layer is 500-900nm.

In the step 3: the stearic acid used is an ethanol solution containing 0.01-0.1mol/L stearic acid, and the solution temperature is 20-25°C;

The reaction time of the low surface energy modification is controlled within 4-7 hours; the contact angle of the composite membrane layer after the low surface energy modification treatment is >150°.

It can be seen from the above-mentioned technical solution provided by the present invention that the above-mentioned preparation method can solve the problems of high cost and environmental pollution of the micro/nano binary rough structure, and provide a new method for constructing the micro/nano binary rough structure on the surface of the aluminum alloy. Structure of the technical means to prepare a multi-layer super-hydrophobic composite film.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

Fig. 1 is a schematic flowchart of a method for preparing a multilayer superhydrophobic composite film layer on an aluminum alloy surface provided by an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The embodiment of the present invention will be described in further detail below in conjunction with the accompanying drawings. As shown in FIG. 1, it is a schematic flow chart of the preparation method of the multilayer superhydrophobic composite film layer on the surface of the aluminum alloy provided by the embodiment of the present invention. The preparation method includes:

Step 1, first performing micro-arc oxidation treatment on the pretreated aluminum alloy sample to obtain a porous micro-arc oxidation ceramic layer with a surface roughness of micron level;

In this step 1, the electrolyte used in the micro-arc oxidation treatment includes: 5-20g/L of sodium silicate, 1-10g/L of potassium hydroxide and 1-10ml/L of glycerol;

And the temperature of the electrolyte is 20-25°C;

The DC pulse voltage used in the micro-arc oxidation treatment is 300-500V;

The obtained porous micro-arc oxidation ceramic layer has a surface roughness of 1-3 μm.

Step 2. Place the obtained ceramic layer in a mixed solution for hydrothermal reaction, generate a hydrotalcite-like film on the surface of the ceramic layer and the inner wall of the hole, and construct a composite film layer with a micro/nano binary rough structure ;

In the step 2, the mixed solution is prepared from metal sulfate (such as magnesium sulfate, zinc sulfate, etc.) and anhydrous sodium sulfate according to the ratio of substance to 1:5; the pH value of the mixed solution is 5 -7, wherein the concentration of the metal sulfate salt is 0.05-0.3mol/L;

The temperature of the hydrothermal reaction is 50-100°C, and the reaction time is 2-48h;

The surface roughness of the obtained composite film layer is 500-900nm.

Step 3, using stearic acid to modify the composite film layer with low surface energy, and finally form a multi-layer super-hydrophobic composite film layer on the surface of the aluminum alloy.

In the step 3, the stearic acid used is an ethanol solution containing 0.01-0.1mol/L stearic acid, and the solution temperature is 20-25°C;

The reaction time of the low surface energy modification is controlled within 4-7 hours; the contact angle of the composite membrane layer after the low surface energy modification treatment is greater than 150°, showing super-hydrophobic performance, and the composite membrane layer has good bonding force with the substrate.

The above-mentioned preparation method is described in detail with specific examples below:

First prepare the micro-arc oxidation ceramic layer, first place the aluminum alloy sample in 50g/L NaOH alkali washing solution, heat it to 60°C, take it out until the surface of the sample is completely black; then clean the sample and place it at 20 % nitric acid solution until the sample recovers the luster of the alloy itself; repeat the above two steps until the surface of the sample is put into the alkali washing solution and immediately turns black; #Sandpaper grinding, after polishing, use acetone, ethanol and deionized solution to ultrasonically clean and dry it for later use; the composition of the micro-arc oxidation electrolyte is: 18g/L sodium silicate, 9g/L potassium hydroxide, 3ml/L glycerine Alcohol; micro-arc oxidation pulse power supply voltage: 360V; the temperature of the electrolyte is controlled at 20-25 °C; the surface roughness of the micro-arc oxidation ceramic layer is 2.4 μm. The treated aluminum alloy sample is connected by aluminum wire, one end is fixed on the anode copper rod, and the end with the sample is immersed in the electrolyte for micro-arc oxidation treatment. After the treatment, the sample was taken out, washed with ethanol solution and then dried.

Then construct the composite hydrotalcite film, specifically prepare the mixed solution first: the concentration of magnesium sulfate is 0.05mol/L, the concentration of anhydrous sodium sulfate is 0.3mol/L, and the pH value of the mixed solution is adjusted to 6.5 by using sodium hydroxide solution; The sample prepared in the above steps was placed vertically in the mixed solution and sealed; after reacting at 70°C for 24 hours, the sample was taken out, washed with ethanol solution and then dried.

Finally, low surface energy substance modification is carried out. Specifically, an ethanol solution of 0.05 mol/L stearic acid is prepared first, and then the sample obtained in the second step is placed vertically in the solution, and the sample is taken out after reacting at room temperature for 5 hours. After washing with ethanol solution and drying in the air, a multilayer superhydrophobic composite film on the surface of the aluminum alloy is finally obtained.

In summary, the method described in the embodiment of the present invention constructs a film layer with a micro/nano binary rough structure by performing micro-arc oxidation treatment on the surface of the aluminum alloy and compounding a hydrotalcite-like film on the surface of the micro-arc oxidation ceramic layer. Using stearic acid to modify the low surface energy of the composite film layer, reduce its surface energy, and construct a superhydrophobic film on the surface of aluminum alloy. Since both the micro-arc oxidation ceramic layer and the hydrotalcite-like film are grown in situ, they have good adhesion to the substrate and are not easy to fall off; and the raw materials used for the composite of the micro-arc oxidation treatment and the hydrotalcite-like film have low toxicity and are not harmful to the environment. Pollution is caused, and the raw materials used are cheap, which is conducive to large-scale industrial production.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (4)

1. a kind of preparation method of aluminum alloy surface multilamellar super-hydrophobic composite film layer is it is characterised in that described preparation method includes：

Step 1, first differential arc oxidation process is carried out to pretreated aluminum alloy specimen, it is micron-sized for obtaining surface roughness Porous arc differential oxide ceramic layer；

Step 2, obtained pottery is placed in mixed solution carries out hydro-thermal reaction, in surface and the hole of described ceramic layer Generate hydrotalcite film at inwall, construct have micro-/receive the composite film of binary coarse structure；

Step 3, using stearic acid, low-surface-energy modification is carried out to described composite film, finally form multilamellar in aluminum alloy surface and surpass Hydrophobic composite membrane layer.

2. according to claim 1 the preparation method of aluminum alloy surface multilamellar super-hydrophobic composite film layer it is characterised in that in institute State in step 1：

Described differential arc oxidation processes used electrolyte and includes：The sodium silicate of 5-20g/L, the potassium hydroxide of 1-10g/L and 1- The glycerol of 10ml/L；And the temperature of described electrolyte is 20-25 DEG C；

It is 300-500V that described differential arc oxidation processes used DC pulse voltage；

The surface roughness of obtained porous arc differential oxide ceramic layer is 1-3 μm.

3. according to claim 1 the preparation method of aluminum alloy surface multilamellar super-hydrophobic composite film layer it is characterised in that in institute State in step 2：

Described mixed solution be sulphuric acid slaine and anhydrous sodium sulfate according to material amount ratio for 1:5 are formulated；This mixing is molten The pH value of liquid is 5-7, and the concentration of wherein said sulphuric acid slaine is 0.05-0.3mol/L；

The temperature of described hydro-thermal reaction is 50-100 DEG C, and the response time is 2-48h；

The surface roughness of obtained composite film is 500-900nm.

4. according to claim 1 the preparation method of aluminum alloy surface multilamellar super-hydrophobic composite film layer it is characterised in that in institute State in step 3：

The stearic acid being adopted is to comprise the stearic ethanol solution of 0.01-0.1mol/L, and solution temperature is 20-25 DEG C；

The response time that described low-surface-energy is modified controls in 4-7h；The contact of the composite film after low-surface-energy moditied processing 150 ° of angle ＞.