1. A preparation method of a titanium alloy anodic oxidation super-hydrophobic coating is characterized by comprising the following steps: and putting the titanium alloy serving as an anode into electrolyte for anodic oxidation to obtain the titanium alloy with an oxide film, and soaking the titanium alloy with the oxide film in a fluorine-containing siloxane solution after heat treatment to obtain the titanium alloy anodic oxidation super-hydrophobic coating.

2. The method of claim 1, wherein the titanium alloy is selected from the group consisting of TA1 titanium alloy, TA2 titanium alloy and TA3 titanium alloy.

3. The method for preparing the titanium alloy anodized superhydrophobic coating according to claim 1, wherein the titanium alloy further comprises the following processing steps before being anodized: and sequentially grinding the titanium alloy by using 800-mesh, 1000-mesh, 2000-mesh and 4000-mesh sand paper and then polishing.

4. The method of claim 1, wherein the electrolyte is an ammonium fluoride alcohol solution.

5. The method for preparing the titanium alloy anodized superhydrophobic coating according to claim 4, wherein the volume fraction of the alcohol in the ammonium fluoride alcohol solution is 80%, and the mass fraction of the ammonium fluoride is 0.3-0.6 wt%.

6. The method for preparing the titanium alloy anodized superhydrophobic coating according to claim 1, wherein the anodized cathode is selected from one of platinum, graphite or pure titanium, and the area ratio of the cathode to the anode is 2: 1; the anodic oxidation conditions are specifically as follows: the oxidation potential is 25-55V, and the oxidation is carried out for 0.5-4 h under the condition of 25 ℃.

7. The method for preparing the titanium alloy anodized superhydrophobic coating according to claim 1, further comprising ultrasonic cleaning with a surfactant before the heat treatment.

8. The method for preparing the titanium alloy anodized superhydrophobic coating according to claim 1, wherein the heat treatment method specifically comprises: treating the mixture in dry hot air at the temperature of 300-600 ℃ for 1-4 h; the soaking time is 6-24 hours; the soaking is carried out under a closed dark condition; the concentration of the fluorine-containing siloxane in the fluorine-containing siloxane solution is 0.01-0.05 mol/L.

9. The titanium alloy anodized superhydrophobic coating prepared by the method for preparing the titanium alloy anodized superhydrophobic coating according to any one of claims 1 to 8.

10. Use of the titanium alloy anodized superhydrophobic coating of claim 9 in a self-cleaning, anti-freeze or anti-friction coating.

Background

From the middle of the 20 th century, titanium alloys have been rapidly developed as high-performance, high-strength light alloy materials. In addition, titanium and titanium alloys have the advantages of good corrosion resistance, heat resistance, biocompatibility, non-magnetism and the like, and are increasingly applied to the fields of ships, biomedicine, vehicles, energy sources, daily necessities and the like. In the field of ships, the titanium alloy is used as a ship body of the ship to resist seawater corrosion and deep water pressure. Titanium alloys also have good monitoring resistance as non-magnetic materials. In the field of automobile manufacturing, titanium alloys have a significant advantage in the development of light automobiles due to their low density, and at present, titanium alloys have been widely used for important parts of automobile connecting rods, gate valves, and the like. In the aerospace field, titanium alloys are widely used for satellites and missiles due to their low density, high strength and high temperature stability. With the increasing share of titanium alloy in all metal material applications, the requirements on various application properties of titanium alloy products are higher and higher.

However, titanium alloys have been limited in their application by their low hardness, poor abrasion resistance, and lack of anti-fouling, anti-fogging, anti-freezing, and self-cleaning properties. Titanium alloy products are often exposed to various stains in everyday life and can be affected by contaminants in appearance and performance. How to achieve the purpose of keeping stable performance of the titanium alloy in various complex environments becomes a current research hotspot. In recent years, surfaces having superhydrophobic properties with contact angles greater than 150 ° and rolling angles less than 10 ° have received particular attention for their potential utility value. How to simply and rapidly prepare the super-hydrophobic coating with excellent performances such as self-cleaning, antifouling, antifogging, anticorrosion, anti-freezing, oil-water separation and the like becomes a difficult problem to be solved urgently by technical personnel in the field.

Disclosure of Invention

The invention aims to provide a preparation method and application of a titanium alloy anodic oxidation super-hydrophobic coating, which aim to solve the problems in the prior art.

In order to achieve the purpose, the invention provides the following scheme:

one of the technical schemes of the invention is as follows: a preparation method of a titanium alloy anodic oxidation super-hydrophobic coating comprises the following steps: and putting the titanium alloy serving as an anode into electrolyte for anodic oxidation to obtain the titanium alloy with an oxide film, and soaking the titanium alloy with the oxide film in a fluorine-containing siloxane solution after heat treatment to obtain the titanium alloy anodic oxidation super-hydrophobic coating.

Further, the titanium alloy is selected from one of a TA1 titanium alloy, a TA2 titanium alloy and a TA3 titanium alloy.

Further, the titanium alloy further comprises the following processing steps before being subjected to anodic oxidation: and sequentially grinding the titanium alloy by using 800-mesh, 1000-mesh, 2000-mesh and 4000-mesh sand paper and then polishing.

Further, the electrolyte is an ammonium fluoride alcohol solution.

Further, the volume fraction of the alcohol in the ammonium fluoride alcohol solution is 80%, and the mass fraction of the ammonium fluoride is 0.3-0.6 wt%.

Further, the anode oxidized cathode is selected from one of platinum, graphite or pure titanium, and the area ratio of the cathode to the anode is 2: 1; the anodic oxidation conditions are specifically as follows: the oxidation potential is 25-55V, and the oxidation is carried out for 0.5-4 h under the condition of 25 ℃.

Further, ultrasonic cleaning by using a surfactant is also included before the heat treatment.

Further, the surfactant is sodium dodecyl sulfate.

Further, the heat treatment method specifically includes: treating the mixture in dry hot air at the temperature of 300-600 ℃ for 1-4 h; the soaking time is 6-24 hours; the soaking is carried out under a closed dark condition; the concentration of the fluorine-containing siloxane in the fluorine-containing siloxane solution is 0.01-0.05 mol/L.

The response of the titanium alloy after anodic oxidation to ultraviolet light is avoided, and the influence of light on the surface is prevented.

The titanium alloy with the oxide film obtained by the anodic reaction is a titanium oxide nanotube array, the titanium oxide nanotube array has a typical rough structure, the surface of the titanium oxide nanotube array has a large amount of hydroxyl, the hydroxyl is a hydrophilic group, so that the titanium dioxide of the nanotube array presents super-hydrophilicity, in an ethanol solution, 1H,1H,2H, 2H-perfluorodecyl triethoxysilane is hydrolyzed to generate silicon hydroxyl, and the hydroxyl on the surface of the nanotube is easy to be condensed with the silicon hydroxyl generated by hydrolysis to form a titanium alloy anodic oxidation super-hydrophobic coating.

The second technical scheme of the invention is as follows: a titanium alloy anodic oxidation super-hydrophobic coating.

The third technical scheme of the invention is as follows: an application of a titanium alloy anodic oxidation super-hydrophobic coating in a self-cleaning, anti-freezing or wear-resistant coating.

The invention discloses the following technical effects:

the preparation process is simple, the required experimental conditions are convenient, an ideal surface oxide film is obtained by an anodic oxidation method, and the super-hydrophobic coating is obtained by modifying a low-surface-energy substance fluorine-containing siloxane. The super-hydrophobic coating prepared by the method is uniform and stable, can be stored for a long time, and has good bonding force between the film layer and the substrate. The paint not only has the characteristics of no oil sticking, no water sticking and no acid-base salt solution sticking, but also has the performances of self cleaning, anti-icing, friction resistance and the like. The super-hydrophobic coating has special surface wettability, so that dust and sewage on the surface layer can be removed by means of external force, and the attractive surface is kept. And the spreading diameter of the liquid drop on the super-hydrophobic coating is smaller, the number of crystal nuclei for crystallization is smaller, and the icing time can be delayed. The prepared anodic oxide film substrate has good binding force and compact and uniform coating, and can obviously improve the friction resistance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a surface topography of an oxide film prepared in example 1 of the present invention;

FIG. 2 is a surface topography of an oxide film prepared in example 2 of the present invention;

FIG. 3 is a surface topography of an oxide film prepared in example 3 of the present invention;

FIG. 4 is a surface topography of an oxide film prepared in example 4 of the present invention;

FIG. 5 is a schematic view of the static water contact angle of the titanium alloy anodized super-hydrophobic coating prepared in example 1 of the present invention;

FIG. 6 is a schematic view of the static water contact angle of the titanium alloy anodized super-hydrophobic coating prepared in example 2 of the present invention;

FIG. 7 is a schematic view of the static water contact angle of the titanium alloy anodized super-hydrophobic coating prepared in example 3 of the present invention;

FIG. 8 is a schematic view of the static water contact angle of the titanium alloy anodized super-hydrophobic coating prepared in example 4 of the present invention;

FIG. 9 is a schematic diagram showing the self-cleaning test results of the titanium alloy anodized super-hydrophobic coating prepared in example 3 of the present invention, wherein a-f show the process of dropping water drops on the sample with the titanium alloy anodized super-hydrophobic coating;

FIG. 10 is a graphical representation of the results of the anti-icing test for the anodized superhydrophobic coating of titanium alloy prepared in example 3 of the invention, wherein a and b represent the time required for the titanium alloy not containing the anodized superhydrophobic coating to ice; c and d represent the time required for the titanium alloy containing the anodized superhydrophobic coating to ice;

FIG. 11 is a schematic diagram of the result of the friction resistance test of the titanium alloy anodized superhydrophobic coating prepared in example 3 of the invention;

FIG. 12 is an SEM and element distribution diagram of the titanium alloy anodized super-hydrophobic coating prepared in example 3 of the invention, wherein a represents an SEM image of a section of the titanium alloy anodized super-hydrophobic coating, and b-d are O, F and element distribution diagrams of Ti element on a cross section of the bottom of the coating respectively.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

Example 1

A preparation method of a titanium alloy anodic oxidation super-hydrophobic coating comprises the following steps:

(1) and respectively grinding the TA2 titanium alloy plate by using metallographic abrasive paper of 800 meshes, 1000 meshes, 2000 meshes and 4000 meshes for 4 times, grinding for 20min each time, washing the plate by using deionized water and acetone, drying, then putting the plate in a metallographic specimen polishing machine for polishing, washing the plate by using the deionized water and the acetone after the polishing is finished, and drying.

(2) Mixing deionized water and ethylene glycol in a volume ratio of 2: 8, uniformly mixing and stirring, cooling to room temperature to obtain an ethylene glycol aqueous solution, adding ammonium fluoride accounting for 0.6 wt% of the mass of the aqueous solution in the ethylene glycol, and stirring in a constant-temperature magnetic stirrer for 10 minutes to obtain the required electrolyte.

(3) And (2) adding the electrolyte prepared in the step (2) into the titanium alloy plate obtained in the step (1) as an anode and a pure titanium sheet as a cathode, oxidizing the titanium alloy plate at the anodic oxidation potential of 25V at the temperature of 25 ℃ for 2h to obtain a TA2 titanium alloy plate containing an oxide film, cleaning the surface of the titanium alloy plate with acetone, placing the titanium alloy plate in a sodium dodecyl sulfate solution with the concentration of 10 wt% to ultrasonically clean the TA2 titanium alloy plate containing the oxide film, and drying the titanium alloy plate in vacuum to obtain the pure oxide film of the nanotube array, wherein the film thickness is 3-5 microns.

(4) Soaking the TA2 titanium alloy plate containing the oxide film in ethanol solution containing 1H,1H,2H, 2H-perfluorodecyl triethoxysilane at the concentration of 0.01mol/L for 12H, and keeping the environment in a closed dark condition to prepare the TA2 titanium alloy anodized super-hydrophobic coating.

Example 2

The difference from example 1 is that the anodic oxidation potential in step (3) was 35V.

Example 3

The difference from example 1 is that the anodic oxidation potential in step (3) was 45V.

Example 4

The difference from example 1 is that the anodic oxidation potential in step (3) was 55V.

Effect example 1

The TA2 titanium alloy plates containing the oxide films prepared in examples 1 to 4 were observed for surface morphology by SEM means, and the measurement results are shown in FIGS. 1 to 4; static water contact angle tests were performed on the TA2 titanium alloy anodized superhydrophobic coatings prepared in examples 1-4, and the results are shown in FIGS. 5-8.

It can be seen from fig. 1 to 4 that the surfaces obtained at different oxidation voltages are different, and it can be seen from fig. 1 that nanotubes are formed at an oxidation potential of 25V, the obtained nanotubes are not uniformly distributed and arranged, the gaps between the tubes are larger, and the nanotube array is more dispersed. Fig. 2 shows the surface topography with the oxidation voltage raised to 35V, the electric field force is increased, and the barrier generation and dissolution rate is basically equal, so that the surface nanotube structure is clearer. As the voltage continues to increase to 45V, the nanotube array formed is regularly aligned and highly ordered. The nanotube orifice is mainly circular, has uniform tube diameter and inner diameter of about 100 nm (figure 3). When the voltage is further increased to 55V or more, the voltage is too high, the energy of fluorine ions is too high, the titanium dioxide barrier layer is excessively dissolved, the wall of the generated nanotube is too thin and is easily damaged, the nanotube becomes unstable, and the collapse of the finally obtained nanotube array is serious (fig. 4). Fig. 5 to 8 show the static contact angles of the surfaces obtained at different oxidation voltages, which were found to be greater than 150 °.

Effect example 2

The TA2 titanium alloy anodized superhydrophobic coating prepared in example 3 is subjected to a self-cleaning test, an anti-icing test and a friction resistance test, the test results are shown in FIGS. 9-11, the cross section of the titanium alloy anodized superhydrophobic coating and element distribution of O, F and Ti elements on the cross section are observed through a scanning electron microscope, and the results are shown in FIG. 12. Outdoor sand-soil mixture is adopted to simulate dust pollution. Firstly, the sample is inclined at 20 degrees to the horizontal plane, the sand-soil mixture is uniformly spread on the surface of the sample, 20 mu L of water drops are slowly dripped on the surface of the sample, and the sand-soil on the surface of the sample is taken away by the rolling of the water drops, so that the sample realizes self-cleaning.

Surface rub resistance tests were performed according to literature test methods (Zhu B, Liu J, Chen Y, et al. Superhydrophosphonic coating with multiscale structure based on crosslinked sized polyacrylates and nanoparticles [ J ]. Surface & Coatings Technology,2017,331:40-47.) with the sample test side down on 1200 mesh metallographic sandpaper and a weight of 100g was applied to the sample. The sample was rubbed back and forth at a speed of 2cm/s, and 10cm each of forward and backward movements were recorded as a cycle, and the contact angle of the surface during rubbing was recorded.

And (3) carrying out an anti-icing experiment on the surface of the sample under the condition of controlling the temperature to be-10 ℃. The temperature of the refrigeration platform is adjusted to the required temperature, a sample is placed on the refrigeration platform, a drop of water with the volume of 5 mu L is dropped on the middle position of the sample, and the time for freezing the water drop is recorded.

It can be seen from fig. 9 to 11 that the prepared coating has good self-cleaning property, anti-icing property and anti-friction property. In fig. 9, for the surface of the superhydrophobic coating, the water droplets are condensed into water droplets and slide down in the oblique direction of the sample due to their own weight. The water droplets can carry away the sand during the sliding process and form a clear path on the surface (fig. 9 (b)). The super-hydrophobic coating has a nano-rough structure and a low surface energy, which not only increases the contact area between the contaminants and the surface, but also prevents water droplets from staying on the surface. Therefore, when water drops roll on the surface, the pollutants are easily taken away, and the purpose of self-cleaning is achieved. As can be seen from fig. 10(a, b), the water drop appears to have a regular hemispherical shape on the surface of the untreated TA2 titanium alloy, with a surface contact angle of 81 °. The untreated TA2 titanium alloy was frozen at-10 deg.C for about 620s, and the surface water drops showed sharp protrusions, indicating that the time for the water drops to freeze on the surface of the TA2 titanium alloy was 620 s. As can be seen from FIG. 10(c, d), the superhydrophobic coating freezes at-10 ℃ for about 4400s to begin to ice. Compared with the untreated TA2 titanium alloy surface, the method has the advantage that the icing time is greatly prolonged, which shows that the super-hydrophobic coating prepared by the experiment has good anti-icing performance. As shown in fig. 11, the contact angle was only slightly changed before 70 cycles of cyclic rubbing, but the contact angle was still over 150 °, showing good superhydrophobicity. This is because the prepared anodic oxide film layer has a good combination with 1H,1H,2H, 2H-perfluorodecyltriethoxysilane, and 1H,1H,2H, 2H-perfluorodecyltriethoxysilane is filled in the inside of the nanotube. During the abrasion process, the super-hydrophobic coating has good abrasion resistance, and only the surface layer 1H,1H,2H, 2H-perfluorodecyl triethoxysilane is abraded. As the number of cycles increases, the superhydrophobic coating begins to break down during wear and the contact angle changes. After more than 120 cycles, the coating on the surface was completely destroyed.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.