阅读说明：本技术 一种超疏水镁合金的制备方法 (Preparation method of super-hydrophobic magnesium alloy ) 是由 王宇鑫 杨一凡 郑松林 于 2020-12-10 设计创作，主要内容包括：本发明公开了一种超疏水镁合金的制备方法,具体为：对进行过表面预处理的镁合金原基体进行激光打标得到标记镁合金基体,所述标记镁合金基体具有凸包状微米结构；对所述标记镁合金基体超声清洗并干燥；室温下,将作为阳极的钴金属板和作为阴极的所述标记镁合金基体浸入Co～(2+)电镀溶液中沉积后,得到待修饰镁合金基体,保留有凸包状微米结构的所述待修饰镁合金基体还具有多级针状微纳米级结构；将所述待修饰镁合金基体进行化学修饰；所述超疏水镁合金基体为保留有凸包状微米结构和针状纳米结构的分级粗糙结构。本发明方法制备了稳定的超疏水镁合金表面,试验参数可控,制备过程环保,具有广阔的应用前景。(The invention discloses a preparation method of a super-hydrophobic magnesium alloy, which comprises the following steps: the magnesium alloy original matrix subjected to surface pretreatment is subjected to laser marking to obtain the magnesium alloyA marked magnesium alloy substrate having a convex hull-like microstructure; ultrasonically cleaning and drying the marked magnesium alloy matrix; immersing a cobalt metal plate as an anode and the marked magnesium alloy substrate as a cathode into Co at room temperature 2+ Depositing in the electroplating solution to obtain a magnesium alloy matrix to be modified, wherein the magnesium alloy matrix to be modified with the convex hull-shaped micron structure is also provided with a multistage acicular micro-nano structure; chemically modifying the magnesium alloy matrix to be modified; the super-hydrophobic magnesium alloy matrix is a hierarchical coarse structure with a convex hull-shaped micro-structure and a needle-shaped nano-structure. The method disclosed by the invention has the advantages that the stable super-hydrophobic magnesium alloy surface is prepared, the test parameters are controllable, the preparation process is environment-friendly, and the method has a wide application prospect.)

1. The preparation method of the super-hydrophobic magnesium alloy is characterized by comprising the following steps of:

firstly, carrying out laser marking on a magnesium alloy original matrix subjected to surface pretreatment to obtain a marked magnesium alloy matrix, wherein the marked magnesium alloy matrix has a convex hull-shaped micrometer structure, the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5-15W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the diameter of a light spot is 0.05-0.1 mm, the scanning speed is 50-200 mm/s, and the distance between two adjacent scanning lines is 0.05-0.1 mm;

step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one;

step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two at room temperature into Co²⁺Depositing in the electroplating solution for 6-10 min to obtain a magnesium alloy matrix to be modified, wherein the anode is communicated with the cathode through a direct current power supply, and the direct current power supplyThe current density applied by the power supply is 5-11 mA/cm²Generating a needle-shaped nano structure on the surface of the magnesium alloy substrate to be modified, which is reserved with the convex bag-shaped micro structure;

step four, chemically modifying the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film;

the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

2. The method for preparing the superhydrophobic magnesium alloy according to claim 1, wherein the method for pretreating the magnesium alloy base body in the first step comprises the following steps:

firstly, polishing the magnesium alloy original matrix;

and step two, carrying out ultrasonic cleaning and drying on the magnesium alloy original matrix polished in the step one.

3. The method for preparing the superhydrophobic magnesium alloy according to claim 2, wherein the polishing treatment in step (i) is to polish the surface of the magnesium alloy primordium by using 800# sandpaper, 1000# sandpaper, 1500# sandpaper and 2000# sandpaper in sequence.

4. The preparation method of the superhydrophobic magnesium alloy according to claim 3, wherein the ultrasonic cleaning and drying method in the second step and the second step comprises: and at room temperature, cleaning the polished target substrate for 3-15 min by using absolute ethyl alcohol for the first time, cleaning the cleaned target substrate for the second time by using deionized water for 3-15 min, and finally purging the target substrate cleaned for the second time by using compressed air for 1-5 min at room temperature.

5. The method for preparing the superhydrophobic magnesium alloy of claim 1, wherein the Co is in step three²⁺The electroplating solution is prepared by adding CoCl at room temperature₂·6H₂O powder and Na₂SO₄The powder was dissolved in 250mL of deionized water, wherein the CoCl₂·6H₂O powder and said Na₂SO₄The mass ratio of the powder is as follows: 5.5-6.5: 1.25 to 2.25.

6. The preparation method of the superhydrophobic magnesium alloy according to claim 1, wherein the chemical modification method in the fourth step is: firstly, the magnesium alloy substrate to be modified in the third step is soaked in the modifying solution, and the super-hydrophobic magnesium alloy substrate film is formed after heat preservation.

7. The preparation method of the superhydrophobic magnesium alloy according to claim 6, wherein the modification solution is a stearic acid-ethanol solution with a concentration of 0.01-0.02 mol/L, and the time for immersing the magnesium alloy substrate to be modified into the modification solution is 1-4 h.

8. The preparation method of the superhydrophobic magnesium alloy according to claim 6, wherein the soaked magnesium alloy substrate to be modified is placed in a muffle furnace at a temperature of 50-200 ℃ for heat preservation for 1-2 hours.

The technical field is as follows:

the invention relates to the technical field of magnesium alloy surface treatment and modification, in particular to a preparation method of a super-hydrophobic magnesium alloy.

Background art:

the magnesium alloy has the advantages of small density, high specific strength, large specific elastic modulus, good heat dissipation, good shock absorption, good damping property, good cutting processing property and the like, and is widely applied to the manufacturing fields of aerospace, new energy automobiles, hydrogen storage devices, medical materials and the like. But at the same time, the magnesium has high chemical activity, the equilibrium potential is low, galvanic corrosion is easy to occur when the magnesium contacts different metals, and the magnesium plays a role of an anode. At room temperature, the surface of the magnesium alloy reacts with oxygen in the air to form a magnesium oxide film, but the magnesium oxide film is loose, so the corrosion resistance is poor, and the surface of the magnesium alloy needs additional processing treatment.

The super-hydrophobic surface has important research value in the industrial field due to natural hydrophobic, slippage, drag reduction and other functions. The preparation of the super-hydrophobic surface cannot be separated from the structure of the surface micro-nano structure, generally speaking, the preparation of the super-hydrophobic surface of the magnesium alloy needs two steps: firstly, constructing a micro-nano coarse structure on the surface of a solid; secondly, modifying a low surface free energy substance on the surface; the existing process needs harsh equipment, expensive reagents and longer period, and a certain distance exists for really applying the super-hydrophobic surface to the field of industrial magnesium alloy corrosion resistance. For example, CN102703886A discloses a method for preparing a magnesium alloy superhydrophobic surface, which comprises pickling a surface, chemically plating silver to obtain a rough surface structure, and then performing surface modification by self-assembly to obtain a superhydrophobic surface with easily rolling water droplets. Therefore, the method for preparing the super-hydrophobic surface with good stability by adopting the method which is simple and easy to operate and has good repeatability has very important significance.

The invention content is as follows:

the invention aims to solve the technical problem of providing a preparation method of a super-hydrophobic magnesium alloy aiming at the defects of the prior art. According to the method, the convex hull-shaped micro structure with controllable form is prepared on the surface of the magnesium alloy by adopting a laser marking machine, the needle-shaped nano structure is obtained after electrochemical cobalt plating, and then surface modification treatment is carried out on the stearic acid-ethanol solution, so that the stable super-hydrophobic surface of the magnesium alloy is prepared.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of a super-hydrophobic magnesium alloy comprises the following steps:

firstly, carrying out laser marking on a magnesium alloy original matrix subjected to surface pretreatment to obtain a marked magnesium alloy matrix, wherein the marked magnesium alloy matrix has a convex hull-shaped micrometer structure, the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5-15W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the diameter of a light spot is 0.05-0.1 mm, the scanning speed is 50-200 mm/s, and the distance between two adjacent scanning lines is 0.05-0.1 mm;

step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one;

step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two at room temperature into Co²⁺Depositing in the electroplating solution for 6-10 min to obtain a magnesium alloy matrix to be modified, wherein the anode is communicated with the cathode through a direct current power supply, and the current density applied by the direct current power supply is 5-11 mA/cm²Generating a needle-shaped nano structure on the surface of the magnesium alloy substrate to be modified, which is reserved with the convex bag-shaped micro structure;

step four, chemically modifying the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film;

the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

Preferably, the method for pretreating the magnesium alloy base body in the first step comprises the following steps:

firstly, polishing the magnesium alloy original matrix;

and step two, carrying out ultrasonic cleaning and drying on the magnesium alloy original matrix polished in the step one.

Preferably, in the polishing treatment method in the step (i), the surface of the magnesium alloy primordium is polished by using 800# sandpaper, 1000# sandpaper, 1500# sandpaper and 2000# sandpaper in sequence.

Preferably, the ultrasonic cleaning and drying method in the second step and the second step comprises the following steps: and at room temperature, cleaning the polished target substrate for 3-15 min by using absolute ethyl alcohol for the first time, cleaning the cleaned target substrate for the second time by using deionized water for 3-15 min, and finally purging the target substrate cleaned for the second time by using compressed air for 1-5 min at room temperature.

Preferably, said Co is present in step three²⁺The electroplating solution is prepared by adding CoCl at room temperature₂·6H₂O powder and Na₂SO₄The powder was dissolved in 250mL of deionized water, wherein the CoCl₂·6H₂O powder and said Na₂SO₄The mass ratio of the powder is as follows: 5.5-6.5: 1.25 to 2.25.

Preferably, the chemical modification method in the fourth step is as follows: firstly, the magnesium alloy substrate to be modified in the third step is soaked in the modifying solution, and the super-hydrophobic magnesium alloy substrate film is formed after heat preservation.

Preferably, the modification solution is a stearic acid-ethanol solution with the concentration of 0.01-0.02 mol/L, and the time for immersing the magnesium alloy substrate to be modified into the modification solution is 1-4 h.

Preferably, the soaked magnesium alloy substrate to be modified is placed in a muffle furnace at the temperature of 50-200 ℃ for heat preservation for 1-2 hours.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

firstly, sequentially carrying out ultrasonic cleaning on a pre-ground magnesium alloy matrix in an ultrasonic cleaning instrument by using ethanol and deionized water; the magnesium alloy substrate is subjected to laser etching by using a laser marking machine, so that a convex hull-shaped micron structure is formed on the surface of the substrate, and the convex hull-shaped micron structure increases the surface area of the substrate to be plated and is beneficial to the deposition of metal ions on the surface of the substrate; the laser marked sample is cleaned and dried, and then is placed in an electrochemical cobalt plating device for electrochemical cobalt plating treatment, compared with the electrochemical treatment of the pretreated magnesium alloy surface, the convex hull-shaped micrometer structure marked on the magnesium alloy substrate increases the contact area between the substrate and the plating layer, improves the binding force between the substrate and the plating layer, ensures that the surface of the magnesium alloy substrate to be modified after electroplating has better stability, and overcomes the defect that the electroplated metal in electrochemical deposition is easy to fall off. Because the surface of the magnesium alloy matrix constructs a hierarchical rough structure with a convex hull-shaped micro-structure and a needle-shaped nano-structure which are compounded, the surface free energy of the sample after treatment can be reduced by soaking and modifying the sample in a stearic acid ethanol solution, so that the surface of the magnesium alloy can obtain a stable super-hydrophobic film layer. The invention combines the laser marking technology and the electrochemical deposition method, the contact angle between the super-hydrophobic surface prepared by the method for preparing the magnesium alloy super-hydrophobic surface by adopting the laser marking and the electrochemical deposition method and water is 156 +/-2 degrees, the rolling angle of water drops on the surface of the material is less than 7 degrees, and the magnesium alloy super-hydrophobic surface has extremely high stability and durability under the room temperature condition, the preparation method is simple, and the treatment process is easy to realize.

Description of the drawings:

FIG. 1(a) is a graph of the trend of contact angle as a function of current density during electrochemical deposition;

FIG. 1(b) is a graph of the trend of roll angle as a function of current density during electrochemical deposition;

FIG. 2(a) is a schematic diagram of a superhydrophobic magnesium alloy matrix film before a self-cleaning performance test;

FIG. 2(b) is a schematic diagram in a self-cleaning performance test of a super-hydrophobic magnesium alloy matrix film;

FIG. 2(c) is a schematic diagram of a superhydrophobic magnesium alloy matrix thin film after a self-cleaning performance test;

FIG. 3 is a graph showing the trend of the contact angle and the rolling angle of the test solution in the stability test along with the soaking time of the 3.5% NaCl solution;

FIG. 4 is a schematic illustration during a contact angle test;

FIG. 5(a) is a surface topography of a marked magnesium alloy substrate obtained after laser marking;

FIG. 5(b) is a partial enlarged view of the surface topography of a marked magnesium alloy substrate obtained after laser marking;

FIG. 6(a) is the surface topography of the magnesium alloy substrate to be modified obtained after electrochemical deposition;

FIG. 6(b) is a partial enlarged view of the surface topography of the magnesium alloy substrate to be modified obtained after electrochemical deposition;

FIG. 7 is an EDS image of the surface of a magnesium alloy substrate to be modified obtained after electrochemical deposition.

The specific implementation mode is as follows:

the present invention is further illustrated by the following examples, which are provided for the purpose of illustration only and are not intended to be limiting.

Example 1

A preparation method of a super-hydrophobic magnesium alloy comprises the following steps:

firstly, carrying out laser marking on a magnesium alloy original substrate AZ31 subjected to surface pretreatment by using a laser marking machine with the model of Shanghai Banyi Byes-30W to obtain a marked magnesium alloy substrate, wherein the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the diameter of a light spot is 0.05mm, the scanning speed is 100mm/s, the distance between two adjacent scanning lines is 0.05mm, and the marked magnesium alloy substrate AZ31 has a convex hull-shaped micrometer structure.

Specifically, the pretreatment method of the magnesium alloy original substrate AZ31 comprises the following steps:

firstly, polishing a magnesium alloy original matrix AZ31, specifically, polishing the surface of the magnesium alloy original matrix by using 800# abrasive paper, 1000# abrasive paper, 1500# abrasive paper and 2000# abrasive paper in sequence to obtain a smooth and bright surface of a magnesium alloy original matrix AZ 31;

and step two, carrying out primary ultrasonic cleaning on the magnesium alloy original substrate AZ31 polished in the step one for 15min by using absolute ethyl alcohol at room temperature, carrying out secondary ultrasonic cleaning on the magnesium alloy original substrate AZ31 subjected to primary cleaning by using deionized water for 15min, and finally blowing and sweeping the magnesium alloy original substrate AZ31 subjected to secondary cleaning by using compressed air for 5min at room temperature to enable the surface of the magnesium alloy original substrate AZ31 to be smooth, clean and dry.

And step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one.

Specifically, at room temperature, carrying out primary ultrasonic cleaning on the marked magnesium alloy matrix for 15min by using absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the marked magnesium alloy matrix subjected to the primary cleaning by using deionized water for 15min, and finally, at room temperature, purging the marked magnesium alloy matrix subjected to the secondary cleaning by using compressed air for 5min to clean and dry the surface of the marked magnesium alloy matrix.

Step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two into Co at room temperature²⁺Depositing in the electroplating solution for 8min to obtain magnesium alloy matrix to be modified, connecting the anode and the cathode via DC power supply with current density of 5mA/cm²And generating a needle-shaped nano structure on the surface of the magnesium alloy substrate to be modified, which is reserved with the convex bag-shaped micro structure.

Specifically, Co²⁺The plating solution was prepared by dissolving 6g of CoCl at room temperature₂·6H₂O powder and 1.75g Na₂SO₄The powder was dissolved in 250mL of deionized water.

And step four, carrying out chemical modification on the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film, wherein the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

Specifically, the chemical modification method comprises the following steps: firstly, the magnesium alloy matrix to be modified in the third step is soaked in a stearic acid-ethanol solution with the concentration of 0.01mol/L for 2 hours, and then the soaked magnesium alloy matrix to be modified is placed in a muffle furnace at the temperature of 120 ℃ for heat preservation for 1 hour to finally form the super-hydrophobic magnesium alloy matrix film.

Example 2

A preparation method of a super-hydrophobic magnesium alloy comprises the following steps:

step one, carrying out laser marking on a magnesium alloy original substrate AZ31 subjected to surface pretreatment by using a laser marking machine with the model of Shanghai Banyi Byes-30W to obtain a marked magnesium alloy substrate, wherein the marked magnesium alloy substrate AZ31 has a convex hull-shaped micrometer structure, the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the spot diameter is 0.05mm, the scanning speed is 100mm/s, and the distance between two adjacent scanning lines is 0.05 mm.

Specifically, the pretreatment method of the magnesium alloy original substrate AZ31 comprises the following steps:

firstly, polishing a magnesium alloy original matrix AZ31, specifically, polishing the surface of the magnesium alloy original matrix by using 800# abrasive paper, 1000# abrasive paper, 1500# abrasive paper and 2000# abrasive paper in sequence to obtain a smooth and bright surface of a magnesium alloy original matrix AZ 31;

and step two, carrying out primary ultrasonic cleaning on the magnesium alloy original substrate AZ31 polished in the step one for 15min by using absolute ethyl alcohol at room temperature, carrying out secondary ultrasonic cleaning on the magnesium alloy original substrate AZ31 subjected to primary cleaning by using deionized water for 15min, and finally blowing and sweeping the magnesium alloy original substrate AZ31 subjected to secondary cleaning by using compressed air for 5min at room temperature to enable the surface of the magnesium alloy original substrate AZ31 to be smooth, clean and dry.

And step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one.

Specifically, at room temperature, carrying out primary ultrasonic cleaning on the marked magnesium alloy matrix for 15min by using absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the marked magnesium alloy matrix subjected to the primary cleaning by using deionized water for 15min, and finally, at room temperature, purging the marked magnesium alloy matrix subjected to the secondary cleaning by using compressed air for 5min to clean and dry the surface of the marked magnesium alloy matrix.

Step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two into Co at room temperature²⁺Depositing in the electroplating solution for 8min to obtain magnesium alloy matrix to be modified, connecting the anode and the cathode via DC power supply with current density of 7mA/cm²The magnesium alloy matrix to be modified has a multi-stage needle-like micro-nano structure with micro-nano scale.

Specifically, Co²⁺The plating solution was prepared by dissolving 6g of CoCl at room temperature₂·6H₂O powder and 1.75g Na₂SO₄The powder was dissolved in 250mL of deionized water.

And step four, carrying out chemical modification on the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film, wherein the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

Specifically, the chemical modification method comprises the following steps: firstly, the magnesium alloy matrix to be modified in the third step is soaked in a stearic acid-ethanol solution with the concentration of 0.01mol/L for 2 hours, and then the soaked magnesium alloy matrix to be modified is placed in a muffle furnace at the temperature of 120 ℃ for heat preservation for 1 hour to finally form the super-hydrophobic magnesium alloy matrix film.

Example 3

A preparation method of a super-hydrophobic magnesium alloy comprises the following steps:

firstly, carrying out laser marking on a magnesium alloy original substrate AZ31 subjected to surface pretreatment by using a laser marking machine with the model of Shanghai Banyi Byes-30W to obtain a marked magnesium alloy substrate, wherein the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the diameter of a light spot is 0.05mm, the scanning speed is 100mm/s, the distance between two adjacent scanning lines is 0.05mm, and the marked magnesium alloy substrate AZ31 has a convex hull-shaped micrometer structure.

Specifically, the pretreatment method of the magnesium alloy original substrate AZ31 comprises the following steps:

firstly, polishing a magnesium alloy original matrix AZ31, specifically, polishing the surface of the magnesium alloy original matrix by using 800# abrasive paper, 1000# abrasive paper, 1500# abrasive paper and 2000# abrasive paper in sequence to obtain a smooth and dust-free surface of a magnesium alloy original matrix AZ 31;

and step two, carrying out primary ultrasonic cleaning on the magnesium alloy original substrate AZ31 polished in the step one for 15min by using absolute ethyl alcohol at room temperature, carrying out secondary ultrasonic cleaning on the magnesium alloy original substrate AZ31 subjected to primary cleaning by using deionized water for 15min, and finally blowing the magnesium alloy original substrate AZ31 subjected to secondary cleaning by using compressed air for 5min at room temperature to enable the surface of the magnesium alloy original substrate AZ31 to be smooth, clean and dry.

And step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one.

Specifically, at room temperature, carrying out primary ultrasonic cleaning on the marked magnesium alloy matrix for 15min by using absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the marked magnesium alloy matrix subjected to the primary cleaning by using deionized water for 15min, and finally, at room temperature, purging the marked magnesium alloy matrix subjected to the secondary cleaning by using compressed air for 5min to clean and dry the surface of the marked magnesium alloy matrix.

Step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two into Co at room temperature²⁺Depositing in the electroplating solution for 8min to obtain magnesium alloy matrix to be modified, connecting the anode and the cathode via DC power supply with current density of 9mA/cm²The magnesium alloy matrix to be modified has a multi-stage needle-like micro-nano structure with micro-nano scale.

Specifically, Co²⁺The plating solution was prepared by dissolving 6g of CoCl at room temperature₂·6H₂O powder and 1.75g Na₂SO₄The powder was dissolved in 250mL of deionized water.

And step four, carrying out chemical modification on the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film, wherein the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

Specifically, the chemical modification method comprises the following steps: firstly, the magnesium alloy matrix to be modified in the third step is soaked in a stearic acid-ethanol solution with the concentration of 0.01mol/L for 2 hours, and then the soaked magnesium alloy matrix to be modified is placed in a muffle furnace at the temperature of 120 ℃ for heat preservation for 1 hour to finally form the super-hydrophobic magnesium alloy matrix film.

Example 4

A preparation method of a super-hydrophobic magnesium alloy comprises the following steps:

firstly, carrying out laser marking on a magnesium alloy original substrate AZ31 subjected to surface pretreatment by using a laser marking machine with the model of Shanghai Banyi Byes-30W to obtain a marked magnesium alloy substrate, wherein the laser marking adopts a grid type laser scanning mode, the rated output power of laser scanning is 5W, the laser frequency is 20KHz, the laser wavelength is 1064nm, the diameter of a light spot is 0.05mm, the scanning speed is 100mm/s, the distance between two adjacent scanning lines is 0.05mm, and the marked magnesium alloy substrate AZ31 has a convex hull-shaped micrometer structure.

Specifically, the pretreatment method of the magnesium alloy original substrate AZ31 comprises the following steps:

firstly, polishing a magnesium alloy original matrix AZ31, specifically, polishing the surface of the magnesium alloy original matrix by using 800# abrasive paper, 1000# abrasive paper, 1500# abrasive paper and 2000# abrasive paper in sequence to obtain a smooth and dust-free surface of a magnesium alloy original matrix AZ 31;

and step two, carrying out primary ultrasonic cleaning on the magnesium alloy original substrate AZ31 polished in the step one for 15min by using absolute ethyl alcohol at room temperature, carrying out secondary ultrasonic cleaning on the magnesium alloy original substrate AZ31 subjected to primary cleaning by using deionized water for 15min, and finally blowing the magnesium alloy original substrate AZ31 subjected to secondary cleaning by using compressed air for 5min at room temperature to enable the surface of the magnesium alloy original substrate AZ31 to be smooth, clean and dry.

And step two, ultrasonically cleaning and drying the marked magnesium alloy matrix in the step one.

Specifically, at room temperature, carrying out primary ultrasonic cleaning on the marked magnesium alloy matrix for 15min by using absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the marked magnesium alloy matrix subjected to the primary cleaning by using deionized water for 15min, and finally, at room temperature, purging the marked magnesium alloy matrix subjected to the secondary cleaning by using compressed air for 5min to clean and dry the surface of the marked magnesium alloy matrix.

Step three, immersing the cobalt metal plate as an anode and the marked magnesium alloy matrix as a cathode in the step two into Co at room temperature²⁺Depositing in the electroplating solution for 8min to obtain magnesium alloy matrix to be modified, wherein the anode and the cathode are communicated via a DC power supply with current density of 11mA/cm²The magnesium alloy matrix to be modified has a multi-stage needle-like micro-nano structure with micro-nano scale.

Specifically, Co²⁺The plating solution was prepared by dissolving 6g of CoCl at room temperature₂·6H₂O powder and 1.75g Na₂SO₄The powder was dissolved in 250mL of deionized water.

And step four, carrying out chemical modification on the magnesium alloy matrix to be modified in the step three to obtain a super-hydrophobic magnesium alloy matrix film, wherein the super-hydrophobic magnesium alloy matrix film is a multi-stage micro-nano composite structure with a convex-bag-shaped micro-structure and a needle-shaped nano-structure.

Specifically, the chemical modification method comprises the following steps: firstly, the magnesium alloy matrix to be modified in the third step is soaked in a stearic acid-ethanol solution with the concentration of 0.01mol/L for 2 hours, and then the soaked magnesium alloy matrix to be modified is placed in a muffle furnace at the temperature of 120 ℃ for heat preservation for 1 hour to finally form the super-hydrophobic magnesium alloy matrix film.

Comparative example 1

Firstly, polishing a magnesium alloy original matrix AZ31, specifically, polishing the surface of the magnesium alloy original matrix by using 800# abrasive paper, 1000# abrasive paper, 1500# abrasive paper and 2000# abrasive paper in sequence to obtain a smooth and bright surface of a magnesium alloy original matrix AZ 31;

step two, carrying out primary ultrasonic cleaning on the magnesium alloy original matrix AZ31 polished in the step one for 15min by using absolute ethyl alcohol at room temperature, carrying out secondary ultrasonic cleaning on the magnesium alloy original matrix AZ31 subjected to the primary cleaning by using deionized water for 15min, and finally blowing a magnesium alloy original matrix AZ31 subjected to the secondary cleaning by using compressed air for 5min at room temperature to enable the surface of the magnesium alloy original matrix AZ31 to be smooth, clean and dry;

and step three, immersing the magnesium alloy original matrix AZ31 pretreated in the step two into a stearic acid-ethanol solution with the concentration of 0.01mol/L for soaking for 2 hours, and then placing the soaked magnesium alloy matrix to be modified in a muffle furnace at the temperature of 120 ℃ for heat preservation for 1 hour to finally form the modified magnesium alloy matrix.

Performance testing

1. Hydrophobic Property measurement-contact Angle and Rolling Angle

The superhydrophobic magnesium alloy substrate films prepared in examples 1 to 4 and the surface of the hydrophobic magnesium alloy substrate formed in comparative example 1 were tested by using a contact angle tester of SDC-350, the volume of a dropped liquid was 5 μ L during the test, the test results are shown in table i, and the schematic diagram of the contact angle and the rolling angle during the test is shown in fig. 4.

TABLE-hydrophobic Property test results

	Contact Angle/(°)	Roll angle/(°)
			Example 1	154.659	10.52
Example 2	156.213	6.53
			Example 3	152.574	9.133
Example 4	149.979	11.275
			Comparative example 1	111.219	＞90

The data in table one show that the hydrophobic property of the surface of the magnesium alloy substrate can be enhanced to a greater extent by using the laser marking and the electrochemical deposition method before the surface of the magnesium alloy substrate is modified by the modifying solution.

As shown in FIGS. 1(a) and 1(b), respectively, which are graphs showing the variation of contact angle and rolling angle with current density during electrochemical deposition, it can be seen from the graphs that as the current density increases, the contact angle shows a tendency of increasing first and then decreasing, the rolling angle shows a tendency of decreasing first and then increasing, and when the current density is 7mA/cm²When the magnesium alloy is used, the contact angle of the magnesium alloy matrix material is the largest, and the optimal superhydrophobic performance is shown.

2. Self-cleaning performance test

The dust was uniformly spread on the superhydrophobic magnesium alloy substrate film prepared in example 2, a dropper was used to drop the superhydrophobic magnesium alloy substrate film into water, and the cleaning condition of the dust on the superhydrophobic magnesium alloy substrate film was observed, the experimental results are shown in fig. 2, it can be seen from the figure that the dust on the superhydrophobic magnesium alloy substrate film was dragged away with the dropping of the liquid droplets, and with the progress of the test, the dust on the superhydrophobic magnesium alloy substrate film was less and less, so that the prepared superhydrophobic surface had better self-cleaning performance.

3. Stability test

The super-hydrophobic magnesium alloy matrix film sample prepared in the example 2 is placed in 3.5% NaCl solution to be soaked for 24 hours, the soaked sample is taken out every 2 hours to test a contact angle and a rolling angle, a schematic diagram in the contact angle and rolling angle testing process is shown in fig. 4, a trend diagram of the change of the contact angle and the rolling angle along with the soaking time is finally drawn, as shown in fig. 3, the change range of the contact angle and the rolling angle is not large as can be seen from fig. 3, and the super-hydrophobic surface prepared by the method has good stability.

Material characterization

Fig. 5 shows the surface morphology of the marked magnesium alloy substrate obtained after laser marking, wherein the marked magnesium alloy substrate has a convex hull-like microstructure, and the convex hull-like microstructure is beneficial to the electrochemical deposition of metal ions on the surface of the substrate and increases the bonding force between the electroplated metal layer and the surface of the substrate.

As shown in fig. 6, the surface morphology of the magnesium alloy substrate to be modified obtained after the electrochemical deposition is shown, the magnesium alloy substrate to be modified has a multi-stage micro-nano coarse structure, and compared with the method of directly performing the electrochemical treatment on the pretreated magnesium alloy surface, the method for marking the convex hull-shaped micro structure on the magnesium alloy substrate increases the contact area between the substrate and the plating layer, improves the binding force between the substrate and the plating layer, enables the surface of the magnesium alloy substrate to be modified after the electroplating to have better stability, and overcomes the defect that the electroplated metal is easy to fall off in the electrochemical deposition.

As shown in fig. 7, which shows an EDS image of the surface of the magnesium alloy substrate to be modified obtained after the electrochemical deposition, it can be known from the map that the cobalt metal is deposited on the surface of the magnesium alloy substrate to be modified, and the content thereof is as high as 23.82%, so that the hydrophobicity of the magnesium alloy substrate film is greatly improved.

Firstly, sequentially carrying out ultrasonic cleaning on a pre-ground magnesium alloy matrix in an ultrasonic cleaning instrument by using ethanol and deionized water; the magnesium alloy substrate is subjected to laser etching by using a laser marking machine, so that a convex hull-shaped micron structure is formed on the surface of the substrate, and the convex hull-shaped micron structure increases the surface area of the substrate to be plated and is beneficial to the deposition of metal ions on the surface of the substrate; the laser marked sample is cleaned and dried, and then is placed in an electrochemical cobalt plating device for electrochemical cobalt plating treatment, compared with the electrochemical treatment of the pretreated magnesium alloy surface, the convex hull-shaped micrometer structure marked on the magnesium alloy substrate increases the contact area between the substrate and the plating layer, improves the binding force between the substrate and the plating layer, ensures that the surface of the magnesium alloy substrate to be modified after electroplating has better stability, and overcomes the defect that the electroplated metal in electrochemical deposition is easy to fall off. Because the surface of the magnesium alloy matrix is constructed into the convex hull-shaped micron structure and the needle-shaped nano structure, the surface free energy of the sample can be reduced by soaking and modifying the treated sample in the stearic acid ethanol solution, so that the surface of the magnesium alloy can obtain a stable super-hydrophobic film layer. The invention combines the laser marking technology and the electrochemical deposition method, the contact angle between the super-hydrophobic surface prepared by the method for preparing the magnesium alloy super-hydrophobic surface by adopting the laser marking and the electrochemical deposition method and water is 156 +/-2 degrees, the rolling angle of water drops on the surface of the material is less than 7 degrees, and the magnesium alloy super-hydrophobic surface has extremely high stability and durability under the room temperature condition, the preparation method is simple, and the treatment process is easy to realize.

Although specific embodiments of the invention have been described, many other forms and modifications of the invention will be apparent to those skilled in the art. It is to be understood that the appended claims and this invention generally cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.