阅读说明：本技术 一种金属表面防结冰的超疏水涂层及其制备方法 (Anti-icing super-hydrophobic coating on metal surface and preparation method thereof ) 是由 项腾飞 魏菲菲 陈德鹏 吕忠 于 2021-06-29 设计创作，主要内容包括：本发明涉及金属类基底超疏水材料技术领域,具体涉及一种金属表面防结冰的超疏水涂层的制备方法,首先采用电沉积法在金属表面制备Zn-Ni合金镀层,然后在Zn-Ni合金基础上采用水热法制备具有“玫瑰花”状微纳米粗糙多孔结构,并对其表面进行化学改性,得到超疏水涂层,该超疏水涂层制备方法简单,环保,仅需两步处理即可构造粗糙的微纳米多孔结构,对金属类材料具有广泛适用性,在一定程度上可以扩大金属材料在不同领域的应用范围。该涂层具有优异的超疏水性能、自清洁性能和化学稳定性,以及优异的防结冰性能,对金属防结冰领域起到了推动作用。(The invention relates to the technical field of metal substrate super-hydrophobic materials, in particular to a preparation method of an anti-icing super-hydrophobic coating on a metal surface. The coating has excellent super-hydrophobic property, self-cleaning property, chemical stability and anti-icing property, and plays a promoting role in the field of metal anti-icing.)

1. The preparation method of the anti-icing super-hydrophobic coating on the metal surface is characterized by comprising the following steps of:

s1: preparing a Zn-Ni alloy coating on the metal surface: taking an insoluble electrode plate as an anode and a metal plate as a cathode, sequentially carrying out oil removal, acid washing, ultrasonic dispersion, scrubbing and activation on a cathode plating piece, carrying out constant-temperature constant-pressure electroplating to obtain a cathode electrodeposition Zn-Ni alloy plating layer sample, and drying at 60 ℃ for 1-2 hours;

s2: preparing Zn-Al layered double hydroxide on the surface of the metal: dissolving aluminum nitrate and sodium carbonate in deionized water to obtain a hydrothermal reaction solvent, then placing the Zn-Ni alloy coating sample obtained in the step S1 into the hydrothermal reaction solvent, sealing, carrying out high-temperature and high-pressure reaction at constant temperature, washing the sample obtained by the reaction with deionized water, and drying at 60 ℃ for 1-2 hours to obtain a hydrothermal sample;

s3: preparing an anti-icing super-hydrophobic coating on the metal surface: and (5) soaking and modifying the hydrothermal sample obtained in the step (S2) for 1-3 h by using a low surface energy modifier, washing the sample by using deionized water, and drying at 60 ℃ for 1-2 h to obtain the anti-icing super-hydrophobic coating.

2. The method for preparing the metal surface anti-icing superhydrophobic coating according to claim 1, wherein the degreasing fluid used in the step S1 is a solution obtained by sequentially dissolving sodium hydroxide, sodium phosphate, sodium carbonate and sodium silicate in ionized water.

3. The method for preparing the anti-icing super-hydrophobic coating on the metal surface as claimed in claim 1, wherein the pickling solution and the activating solution in the step S1 are both prepared by diluting hydrochloric acid.

4. The method for preparing the anti-icing super-hydrophobic coating on the metal surface according to claim 1, wherein the electroplating in the step S1 is performed in an acidic plating solution, and the pH of the acidic plating solution is adjusted to 5 by hydrochloric acid and ammonia water.

5. The method for preparing the anti-icing super-hydrophobic coating on the metal surface according to claim 4, wherein the acidic plating solution is any one of potassium chloride, ammonium chloride and a mixed system of potassium chloride and ammonium chloride.

6. The method for preparing the anti-icing super-hydrophobic coating on the metal surface according to claim 1, wherein the constant-temperature electroplating temperature in the step S1 is 35 ℃, and the electroplating time is 10-20 min.

7. The method for preparing the anti-icing super-hydrophobic coating on the metal surface as claimed in claim 1, wherein the mass ratio of the aluminum nitrate to the sodium carbonate in the hydrothermal reaction solvent in the step S2 is 1:2 to 4.

8. The method for preparing the metal surface anti-icing super-hydrophobic coating according to claim 1, wherein the temperature of the hydrothermal reaction in the step S2 is 60-100 ℃, and the hydrothermal reaction time is 5-7 h.

9. The method for preparing the metal surface anti-icing super-hydrophobic coating according to claim 1, wherein the low surface energy modifier is a 1mol/L stearic acid-ethanol solution or a 1mol/L myristic acid-ethanol solution in the step S3.

10. An anti-icing super-hydrophobic coating on a metal surface prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of super-hydrophobic materials, in particular to an anti-icing super-hydrophobic coating on a metal surface and a preparation method thereof.

Background

The problem that the surface of the metal is inevitably frosted and frozen at low temperature is a globalization problem. Over the past decades, people have often used traditional active methods to de/anti-ice. For example, mechanical de-icing, high temperature de-icing, chemical de-icing, etc., and in some special cases also manual de-icing has to be applied. However, these active deicing methods often consume a large amount of energy, cause resource waste, pollute the environment, and even threaten the personal safety of workers.

In recent years, inspired by various animal and plant surfaces, the bionic super-hydrophobic surface is widely researched. The super-hydrophobic surface has excellent water repellency, self-cleaning, corrosion resistance, anti-icing, oil-water separation and other performances, so that the super-hydrophobic surface is gradually applied to various fields. The superhydrophobic surface has a water contact angle above 150 ° and a water roll angle below 10 °. Wherein the coarse structure and low surface energy are two major factors affecting the performance of the superhydrophobic surface. Because the air medium exists in the micro-nano rough structure gap, the contact area between the water drop and the super-hydrophobic rough surface is very small, and a Cassie wetting model is formed. Therefore, the nucleation sites on the surface are reduced in a low-temperature environment, and the icing probability of the surface is reduced. Meanwhile, the low surface energy also increases the energy barrier of temperature transmission, and the surface anti-icing protection is realized.

Many methods have been developed to prepare superhydrophobic coatings. Such as laser etching, templating, vapor deposition, sol-gel, electrospinning, hydrothermal synthesis, and the like. The methods promote the progress of the surface field in the direction of anti-icing to a certain extent, but the preparation process is complicated and high in cost, more importantly, the method is limited in applicable medium and only applicable to a single substance surface, and the application of the super-hydrophobic anti-icing surface is severely limited.

In view of the above-mentioned drawbacks, the inventors of the present invention have finally obtained the present invention through a long period of research and practice.

Disclosure of Invention

The invention aims to solve the problems that the existing preparation process for the anti-icing super-hydrophobic surface of the metal surface is complex and is suitable for singly fixing a certain metal material, and provides an anti-icing super-hydrophobic coating of the metal surface and a preparation method thereof.

In order to achieve the aim, the invention discloses a preparation method of an anti-icing super-hydrophobic coating on a metal surface, which comprises the following steps:

s1: preparing a Zn-Ni alloy coating on the metal surface: taking an insoluble electrode plate as an anode and a metal plate as a cathode, sequentially carrying out oil removal, acid washing, ultrasonic dispersion, scrubbing and activation on a cathode plating piece, respectively connecting the electrode plate with the anode and the cathode of a direct-current power supply through leads, carrying out constant-temperature and constant-voltage electroplating, and drying an obtained cathode electrodeposition Zn-Ni alloy plating layer sample at 60 ℃ for 1-2 hours;

s2: preparing Zn-Al layered double hydroxide on the surface of the metal: dissolving aluminum nitrate and sodium carbonate in deionized water to obtain a hydrothermal reaction solvent, then placing the Zn-Ni alloy coating sample obtained in the step S1 into the hydrothermal reaction solvent, sealing, carrying out high-temperature and high-pressure reaction at constant temperature, washing the sample obtained by the reaction with deionized water, and drying at 60 ℃ for 1-2 hours to obtain a hydrothermal sample;

s3: preparing an anti-icing super-hydrophobic coating on the metal surface: and (5) soaking and modifying the hydrothermal sample obtained in the step (S2) for 1-3 h by using a low surface energy modifier, washing the sample by using deionized water, and drying at 60 ℃ for 1-2 h to obtain the anti-icing super-hydrophobic coating.

The deoiling liquid adopted in the step S1 is a solution obtained by sequentially dissolving sodium hydroxide, sodium phosphate, sodium carbonate and sodium silicate in ionized water.

In the step S1, the pickling solution and the activating solution are both prepared by diluting hydrochloric acid.

The plating in step S1 is performed in an acidic bath adjusted to pH 5 by hydrochloric acid and ammonia water.

The acid plating solution is any one of potassium chloride, ammonium chloride and a mixed system of potassium chloride and ammonium chloride.

In the step S1, the constant-temperature electroplating temperature is 35 ℃, and the electroplating time is 10-20 min.

In the hydrothermal reaction solvent in the step S2, the mass ratio of aluminum nitrate to sodium carbonate is 1:2 to 4.

The temperature of the hydrothermal reaction in the step S2 is 60-100 ℃, and the hydrothermal reaction time is 5-7 h.

In the step S3, the low surface energy modifier is a 1mol/L stearic acid-ethanol solution or a 1mol/L myristic acid-ethanol solution.

The invention also discloses the anti-icing super-hydrophobic coating on the metal surface prepared by the preparation method.

The reaction that occurs when a myristic acid-ethanol solution is used as a low surface energy modifier is as follows:

the carboxyl group in the acid combines with the hydroxyl group in the Zn-Al layered double hydroxide to make the coating hydrophobic.

Compared with the prior art, the invention has the beneficial effects that:

1. the method comprises the steps of preparing a rose-shaped micro-nano rough porous structure on the basis of a Zn-Ni alloy by adopting a hydrothermal method, carrying out chemical modification on the surface of the rose-shaped micro-nano rough porous structure to obtain a super-hydrophobic coating, adjusting the hydrothermal reaction temperature and time and the mass ratio of aluminum nitrate to sodium carbonate to control the size of the rose-shaped micro-nano porous structure, and further controlling the non-wettability and the anti-icing performance of the super-hydrophobic surface;

2. the super-hydrophobic coating prepared by the invention has micro-nano porous structures with different sizes, and can improve the roughness of the surface of the coating;

3. the super-hydrophobic coating prepared by the method has excellent hydrophobicity, self-cleaning property and chemical stability;

4. the super-hydrophobic coating prepared by the invention has excellent anti-icing performance under different low temperature environments;

5. the super-hydrophobic coating prepared by the method is suitable for the surface of any metal matrix, and the applicability of the super-hydrophobic coating is improved;

6. the method for preparing the super-hydrophobic coating has the advantages of simple and easily-controlled process, low cost and environmental protection.

Drawings

Fig. 1 is a SEM image of a "rose" -shaped micro-nano porous structure of a hydrothermal sample prepared in example 1 of the present invention;

FIG. 2 is an XRD pattern of a hydrothermal sample prepared in example 1 of the present invention;

FIG. 3 is a static water contact angle and a dynamic sliding process of the super-hydrophobic coating prepared in example 1 of the present invention;

FIG. 4 is the chemical stability of the superhydrophobic coating prepared in example 1 of the invention;

FIG. 5 is a schematic view of an anti-icing test system;

FIG. 6 is a delayed icing process at a low temperature of-10 ℃ for the superhydrophobic coating prepared in example 1 of the invention;

fig. 7 is a SEM image and a static water contact angle of a rose-shaped micro-nano porous structure of a hydrothermal sample prepared in embodiments 2 to 5 of the present invention.

Detailed Description

The above and further features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.

Example 1

Step 1, preparation of Zn-Ni alloy coating on metal surface

Adding 500mL of deionized water into a beaker, heating to 70 ℃, sequentially adding 107g of nickel chloride, 75g of zinc chloride, 30g of boric acid, 35 g of ammonium chloride, 200g of potassium chloride, 20g of potassium citrate and 0.1g of sodium dodecyl benzene sulfonate, dissolving, and adding deionized water to the 1L scale mark of the mixed solution to obtain an acidic potassium chloride plating solution; adjusting the pH value of the electrolyte solution to 5 by using hydrochloric acid or ammonia water; dissolving 2.5g of sodium hydroxide, 3.5g of sodium phosphate, 3.5g of sodium carbonate and 2.5g of sodium silicate in 100mL of ionized water to prepare deoiling liquid; preparing a pickling solution by using 125mol/L hydrochloric acid; preparing an activating solution by using 30mol/L hydrochloric acid;

then the cathode plating piece is sequentially degreased,A series of pretreatments such as acid washing, ultrasonic dispersion, scrubbing, activation and the like are carried out, so as to remove grease and impurities on the surface of the metal; using insoluble electrode plate as anode, stainless steel as cathode, connecting the electrode plate with anode and cathode of DC power supply via wires, and controlling current constant at 0.5A/cm at 35 deg.C²Electroplating for 10min to obtain a Zn-Ni alloy coating, and drying the cathode electro-deposition Zn-Ni alloy sample in a 60 ℃ oven for 2 h.

Step 2, preparation of Zn-Al layered double hydroxide on metal surface

Dissolving aluminum nitrate and sodium carbonate in 80mL of deionized water, wherein the mass ratio of the aluminum nitrate to the sodium carbonate is 1:3, and obtaining the hydrothermal reaction solvent. And then placing the hydrothermal solvent in a high-pressure reaction kettle, inclining the Zn-Ni alloy coating sample by a certain angle, placing the sample in the high-pressure reaction kettle (ensuring the sufficient reaction of the sample), sealing, and then placing the high-pressure reaction kettle in a drying oven at 100 ℃ for hydrothermal reaction for 7 hours to obtain a hydrothermal sample. The sample was washed with deionized water and dried in an oven at 60 ℃ for 2 h.

Step 3, preparation of anti-icing super-hydrophobic coating on metal surface

Preparing a low surface energy modifier by adopting a 1mol/L octadecanoic acid-ethanol solution, soaking and modifying a hydrothermal sample in a stearic acid-ethanol solution for 2 hours, then washing the sample by deionized water, and drying the sample in a 60 ℃ drying oven for 2 hours to obtain the anti-icing super-hydrophobic coating.

Fig. 1 is an SEM image of a "rose" -shaped micro-nano porous structure of the hydrothermal sample prepared in example 1, from which it can be seen that the surface of the hydrothermal sample shows a uniform micro-nano porous structure, and further the enlarged morphology shows that the "rose" -shaped porous structure is formed by the micro-nano sheet-shaped structures being connected in a staggered manner, and the surface shows "holes" and "protrusions" with different sizes.

Fig. 2 is XRD patterns of the Zn — Ni alloy sample prepared in example 1 and the hydrothermal sample, and we found that new diffraction peaks appeared on the surface of the sample at 11.72 ° and 34.56 ° after the hydrothermal reaction, and the two new diffraction peaks correspond to (003) and (009) crystal planes of Zn-Al-LDHs, respectively, indicating the formation of Zn-Al double metal hydroxide.

Fig. 3 is an image of the dynamic and static wettability of the superhydrophobic surface coating prepared in example 1, and it can be seen that the superhydrophobic surface has a water contact angle as high as 160 ° and a water sliding angle as low as 3 ° showing good non-wettability.

For the chemical stability test of the super-hydrophobic coating prepared in example 1, a contact angle tester is used to measure the static water contact angle (the required pH value is adjusted by HCL and NaOH) of 5 μ L of liquid drops with different pH values, fig. 4 is a chemical stability test result diagram, and it can be seen from the test result that the strong acid and strong base liquid drops still maintain a water contact angle higher than 155 ° on the surface of the coating, and show excellent acid and alkali corrosion resistance.

The anti-icing performance of the surface was observed using a refrigeration device and a contact angle tester system, the experiment was performed at room temperature, when the refrigeration device was lowered to the target temperature, the sample was placed on a sample stage, 5 μ L of water was dropped on the surface of the sample using a micro needle, and the test schematic is shown in fig. 5. The high-speed camera is used for recording the shapes of water drops at different time, the icing condition of the super-hydrophobic sample in a low-temperature environment is observed in real time, and fig. 6 is an anti-icing performance test result diagram of the super-hydrophobic coating prepared in the embodiment 1, so that the super-hydrophobic coating still has good anti-icing performance at the temperature of-10 ℃ and can delay icing for 194 s.

Example 2

The electroplating time in the step 1 of the embodiment 1 is changed into 20min, the mass ratio of aluminum nitrate to sodium carbonate in the step 2 is changed into 1:2, a micro-nano porous structure is obtained, the low surface energy modifier in the structural step 3 is changed into a 1mol/L myristic acid-ethanol solution, the rest processes are the same as those in the embodiment 1, and the surface scanning image and the static water contact angle are shown in a figure 7 a. The static water contact angle of the surface of the sample can reach 149.1 degrees, and the surface of the sample presents a needle-shaped micro-nano porous structure appearance.

Example 3

The mass ratio of aluminum nitrate to sodium carbonate in step 2 of example 1 was changed to 1:1, the hydrothermal reaction temperature was changed to 60 ℃, the hydrothermal reaction time was changed to 3 hours, a micro-nano porous structure was obtained, the low surface energy modifier in structural step 3 was changed to 1mol/L myristic acid-ethanol solution, the rest of the procedure was the same as that of example 1, and the surface scan image and the static water contact angle were as shown in fig. 7 b. The static water contact angle of the surface of the sample can reach 138.6 degrees, and the surface of the sample presents a randomly distributed wheat-ear-shaped structure appearance.

Example 4

The mass ratio of aluminum nitrate to sodium carbonate in step 2 of example 1 was changed to 1:2, the hydrothermal reaction temperature was changed to 80 ℃, and the hydrothermal reaction time was changed to 5 hours, so as to obtain a micro-nano porous structure, and the rest of the process was the same as that of example 1, and the surface scanning image and the static water contact angle thereof are shown in fig. 7 c. The static water contact angle of the surface of the sample can reach 146.8 degrees, and the surface of the sample presents a floccule structure appearance. The morphology and wettability of the porous structure are adjusted by different parameters.

Example 5

The hydrothermal reaction temperature in step 2 of example 1 was changed to 80 ℃, the hydrothermal reaction time was changed to 5 hours, micro-nano-porous materials were obtained, and a rough superhydrophobic anti-icing surface was obtained, the rest of the process was the same as that of example 1, and the surface scanning image and the static water contact angle were shown in fig. 7 d. The static water contact angle of the surface of the sample is as high as 154.6 degrees, and the surface of the sample presents micro-nano sheet structures with different sizes.

The foregoing is merely a preferred embodiment of the invention, which is intended to be illustrative and not limiting. It will be understood by those skilled in the art that various changes, modifications and equivalents may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.