Method for preparing superhydrophobic aluminum oxide coating on magnesium alloy surface

Abstract

The application belongs to the field of surface treatment of metal materials, and particularly discloses a method for preparing a super-hydrophobic aluminum oxide coating on a magnesium alloy surface. The method comprises the following steps: placing the magnesium alloy into an aluminum chloride solution, heating in a water bath, and then blowing dry under an argon atmosphere for standby; combining high-temperature heating to cause a dehydration reaction; and finally using a polydimethylsiloxane (PDMS) vapor deposition surface modification method to prepare the super-hydrophobic aluminum oxide coating. The coating surface has a static contact angle of 163.6° with respect to water, and a rolling angle of 3.5°. The coating has mechanical chemical stability and corrosion resistance. The method is simple and convenient, low in cost, and has a large-scale application prospect.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment technology, and specifically relates to a method for generating a superhydrophobic aluminum oxide coating on a magnesium alloy surface. Background Technology

[0002] Magnesium alloys are hailed as one of the most promising green engineering materials of the 21st century, possessing not only excellent physical and mechanical properties but also good biocompatibility. They are widely used in aerospace, transportation, and medical devices. However, magnesium has an extremely low electrode potential, making its surface prone to oxidation and severe corrosion, especially in humid environments containing corrosive media. This poor corrosion resistance limits the widespread application of magnesium alloys. Finding a simple, convenient, low-cost, and easily implemented surface modification method to improve the corrosion resistance of magnesium alloys in the environment (media) can expand their application scope. Constructing a superhydrophobic coating with both mechanical and chemical stability on the surface of magnesium alloy materials can effectively block the contact between corrosive media and the magnesium alloy substrate, effectively improving the corrosion resistance of magnesium alloys. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a superhydrophobic alumina coating on a magnesium alloy surface. This method is simple, convenient, has good repeatability, low cost, and is universally applicable.

[0004] This invention provides a method for preparing a superhydrophobic alumina coating on a magnesium alloy surface, comprising the following steps:

[0005] (1) Pretreatment of magnesium alloys;

[0006] (2) The pretreated magnesium alloy is placed in aluminum trichloride solution and heated in a water bath at 50-70°C for 3-5 hours. After the magnesium alloy is heated in the water bath and cooled to room temperature, it is washed with deionized water and dried under an argon atmosphere for later use. The dried magnesium alloy is then heated at 450°C for 10-20 minutes and cooled to room temperature.

[0007] (3) The magnesium alloy after step (2) is treated by PDMS vapor deposition surface modification method, that is, a superhydrophobic alumina coating is prepared on the surface of the magnesium alloy.

[0008] Preferably, the pretreatment step of the magnesium alloy includes mechanical polishing of the magnesium alloy surface, followed by ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water in sequence.

[0009] Preferably, the concentration of the aluminum trichloride solution is 0.1-0.15 mol / L.

[0010] Preferably, the method of surface modification with PDMS vapor deposition for treating the magnesium alloy after step (2) involves placing PDMS liquid in a glass container and placing the magnesium alloy after step (2) in a second glass container, with both containers placed in a sealed reactor and heated at 235°C for 0.5 h.

[0011] The chemical reaction equations for the reaction of the magnesium alloy with aluminum trichloride solution in a water bath and the high-temperature dehydration are as follows: 2Mg + 2AlCl3 + 6H2O = 3MgCl2 + 2Al(OH)3 + H2 (water bath heating); 2Al(OH)3 = Al2O3 + 3H2O (reaction at 450℃).

[0012] The beneficial effects of this invention are as follows: using aluminum trichloride as a precursor, an alumina micro-nano composite structure is prepared through hydrothermal reaction and high-temperature dehydration. Combined with PDMS vapor deposition surface modification, a superhydrophobic alumina coating is prepared on the surface of a magnesium alloy. The obtained superhydrophobic alumina coating has a static contact angle of 163° and a roll-off angle of 3.5° to water. The coating has mechanical and chemical stability and corrosion resistance. Moreover, the method is simple, convenient, reproducible, and low-cost, and has excellent prospects for engineering applications. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0014] In this invention, the method for preparing a superhydrophobic alumina coating on a magnesium alloy surface includes the following steps:

[0015] (1) Pretreatment of magnesium alloys;

[0016] (2) The pretreated magnesium alloy is placed in aluminum trichloride solution and heated in a water bath at 50-70°C for 3-5 hours. After the magnesium alloy is heated in the water bath and cooled to room temperature, it is washed with deionized water and dried under an argon atmosphere for later use. The dried magnesium alloy is then heated at 450°C for 10-20 minutes and cooled to room temperature to obtain the treated magnesium alloy.

[0017] (3) The magnesium alloy treated in step (2) is treated by the method of surface modification by dimethylsiloxane (PDMS) vapor deposition, that is, a superhydrophobic alumina coating is prepared on the surface of the magnesium alloy.

[0018] Preferably, the pretreatment step of the magnesium alloy includes mechanical polishing of the magnesium alloy surface, followed by ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water in sequence.

[0019] Preferably, the concentration of the aluminum trichloride solution is 0.1-0.15 mol / L.

[0020] Preferably, the method of surface modification with PDMS vapor deposition for treating the magnesium alloy after step (2) involves placing PDMS liquid in a glass container and placing the magnesium alloy after step (2) in a second glass container, with both containers placed in a sealed reactor and heated at 235°C for 0.5 h.

[0021] Example 1:

[0022] The pretreated magnesium alloy was placed in a 0.1 mol / L aluminum trichloride solution and heated in a water bath at 50°C for 3 hours. After removal, it was washed with deionized water and dried under an argon atmosphere for later use. The magnesium alloy was then heated at 450°C for 10 minutes, cooled to room temperature, and surface-modified by PDMS vapor deposition to prepare a superhydrophobic alumina coating on the magnesium alloy surface. This coating exhibits mechanochemical stability and corrosion resistance.

[0023] Example 2:

[0024] The pretreated magnesium alloy was placed in a 0.12 mol / L aluminum trichloride solution and heated in a water bath at 55°C for 3 hours. After removal, it was washed with deionized water and dried under an argon atmosphere for later use. The magnesium alloy was then heated at 450°C for 15 minutes, cooled to room temperature, and surface-modified by PDMS vapor deposition to prepare a superhydrophobic alumina coating on the magnesium alloy surface. This coating exhibits mechanochemical stability and corrosion resistance.

[0025] Example 3:

[0026] The pretreated magnesium alloy was placed in a 0.15 mol / L aluminum trichloride solution and heated in a water bath at 70°C for 3 hours. After removal, it was washed with deionized water and dried under an argon atmosphere for later use. The magnesium alloy was then heated at 450°C for 20 minutes, cooled to room temperature, and surface-modified by PDMS vapor deposition to prepare a superhydrophobic alumina coating on the magnesium alloy surface. This coating exhibits mechanochemical stability and corrosion resistance.

[0027] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A method for preparing a superhydrophobic alumina coating on a magnesium alloy surface, characterized in that, Includes the following steps: (1) Pretreatment of magnesium alloys; (2) The pretreated magnesium alloy is placed in aluminum trichloride solution and heated in a water bath at 50-70°C for 3-5 hours. After the magnesium alloy is heated in the water bath and cooled to room temperature, it is washed with deionized water and dried under an argon atmosphere for later use. The dried magnesium alloy is then heated at 450°C for 10-20 minutes and cooled to room temperature. (3) The magnesium alloy after step (2) is treated by PDMS vapor deposition surface modification method, that is, a superhydrophobic alumina coating is prepared on the surface of the magnesium alloy.

2. The method according to claim 1, characterized in that, The pretreatment steps for the magnesium alloy include mechanical polishing of the magnesium alloy surface, followed by ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water in sequence.

3. The method according to claim 1, characterized in that, The concentration of the aluminum trichloride solution is 0.1-0.15 mol / L.

4. The method according to claim 1, characterized in that, The method of surface modification with PDMS vapor deposition involves placing PDMS liquid in a glass container and placing the magnesium alloy treated in step (2) in a second glass container. Both containers are placed in a sealed reactor and heated at 235°C for 0.5 hours.