阅读说明：本技术 超疏水碳钢及其制备方法 (Super-hydrophobic carbon steel and preparation method thereof ) 是由 颜蜀雋 金政伟 石立军 张安贵 潘爱庶 井云环 邱守贤 庄壮 王亮 丁鹏 苏慧 于 2021-01-12 设计创作，主要内容包括：本发明涉及超疏水材料领域,公开了一种超疏水碳钢及其制备方法。碳钢基材的表面存在原位生长的纳米片结构,所述纳米片结构表面修饰有低表面能物质。该制备方法工艺简单、经济,在一定程度上解决了超疏水材料制备条件苛刻、成本高、步骤复杂繁琐的问题,且所制备的超疏水碳钢具有超疏水性,适用范围广,可以应用到防腐、防冰、减阻等领域。(The invention relates to the field of super-hydrophobic materials, and discloses super-hydrophobic carbon steel and a preparation method thereof. The surface of the carbon steel substrate has a nano-sheet structure grown in situ, and the surface of the nano-sheet structure is modified with a low surface energy substance. The preparation method is simple and economical in process, and solves the problems of harsh preparation conditions, high cost and complex and fussy steps of the super-hydrophobic material to a certain extent, and the prepared super-hydrophobic carbon steel has super-hydrophobicity and wide application range, and can be applied to the fields of corrosion prevention, ice prevention, drag reduction and the like.)

1. The super-hydrophobic carbon steel is characterized by comprising a carbon steel substrate and a nanosheet layer growing on the surface of the carbon steel substrate in situ, wherein a low-surface-energy substance is modified on the surface of the nanosheet layer.

2. The superhydrophobic carbon steel of claim 1, wherein in the nanosheet layer, the nanosheets grow in a two-dimensional plane along a direction of a 110 crystal plane and are distributed on the surface of the carbon steel substrate;

preferably, the thickness of the nanosheet layer is 20-50 nm;

preferably, the individual nanosheets are 0.2-1 μm in length and 20-50nm in thickness;

preferably, the nanoplatelets comprise Fe, Fe₃O₄And optionally Fe₂O₃；

More preferably, the content of the Fe element in the nanosheet layer is 30-40 wt% and the content of the O element is 60-70 wt%, based on the total weight of the Fe element and the O element.

3. The superhydrophobic carbon steel of claim 1 or 2, wherein the low surface energy substance is selected from at least one of a silane-based low surface energy substance, a fatty acid-based low surface energy substance, and paraffin wax.

4. A method for preparing super-hydrophobic carbon steel is characterized by comprising the following steps: and (3) sequentially carrying out pretreatment, in-situ growth of a nanosheet structure and low surface energy treatment on the carbon steel substrate to obtain the super-hydrophobic carbon steel.

5. The method of claim 4, wherein the method further comprises:

(1) pretreatment: etching the carbon steel base material to obtain an etched carbon steel base material;

(2) in-situ growth of the nanosheet structure: annealing the etched carbon steel substrate in an oxygen atmosphere to obtain the carbon steel substrate with the nano-sheet structure grown in situ;

(3) low surface energy treatment: and contacting the carbon steel substrate with the nano-sheet structure grown in situ with a low-surface-energy substance to obtain the super-hydrophobic carbon steel.

6. The method of claim 5, wherein the method further comprises: before etching the carbon steel base material, removing impurities from the carbon steel base material.

7. The method of claim 5 or 6, wherein in step (1), the etching comprises: performing surface etching on the carbon steel base material subjected to impurity removal treatment by using inorganic acid to obtain an etched carbon steel base material;

preferably, the concentration of the inorganic acid is 1 to 5 wt%;

preferably, the etching time is 3-5 min.

8. The method of claim 5, wherein in step (2), the annealing comprises: heating the etched carbon steel substrate to 400-600 ℃ in an oxygen atmosphere, then annealing for 1-2h, and cooling to room temperature to obtain the carbon steel substrate with the in-situ growth nanosheet structure;

preferably, the rate of temperature rise is 4-6 deg.C/min.

9. The method according to claim 4 or 5, wherein in step (3), the contacting time is 0.2-1 h; and/or

The low surface energy substance is at least one selected from the group consisting of silane-based low surface energy substances, fatty acid-based low surface energy substances, and paraffin.

10. A superhydrophobic carbon steel prepared according to the method of any one of claims 4-9.

Technical Field

The invention relates to the field of super-hydrophobic materials, in particular to super-hydrophobic carbon steel and a preparation method thereof.

Background

The super-hydrophobic coating is a novel material with special surface properties, and has huge application prospects in the aspects of self-cleaning, corrosion prevention, ice prevention, fog prevention, snow prevention, drag reduction and the like. There are two main approaches to the preparation of superhydrophobic surfaces at present: and constructing a rough structure on the surface of the material and carrying out low surface energy modification, or directly constructing the rough structure on the surface of the low surface energy material. Since the formation of a rough structure on the surface of a low surface energy material may limit the application range of the superhydrophobic surface to a certain extent, the first approach is generally adopted to prepare the superhydrophobic surface.

The methods for preparing the super-hydrophobic surface microstructure are many, but generally complex and tedious processes are needed, the preparation conditions are harsh, the cost is high, and large-scale preparation and application are difficult. For example, CN108977801A discloses a method for preparing a three-dimensional nanostructure steel plate film with high water resistance and corrosion resistance, which has the disadvantages of complex process and harsh preparation conditions; the cost is high, and the large-scale preparation and application are difficult.

Disclosure of Invention

The invention aims to solve the problems of complex process, harsh preparation conditions and high cost in the process of preparing a super-hydrophobic steel plate in the prior art, and provides super-hydrophobic carbon steel and a preparation method thereof.

In order to achieve the above object, a first aspect of the present invention provides an ultra-hydrophobic carbon steel, which includes a carbon steel substrate and a nanosheet layer grown in situ on the surface of the carbon steel substrate, wherein the surface of the nanosheet layer is modified with a low surface energy substance.

The second aspect of the invention provides a method for preparing super-hydrophobic carbon steel, which comprises the following steps: the method comprises the following steps: and (3) sequentially carrying out pretreatment, in-situ growth of a nanosheet structure and low surface energy treatment on the carbon steel substrate to obtain the super-hydrophobic carbon steel.

A third aspect of the invention provides a superhydrophobic carbon steel prepared according to the method described above.

The material used in the invention has low price, simple and convenient operation, and more complex traditional preparation methods such as a hydrothermal method, and the like, and the preparation process has absolute advantages. The invention has wide applicability and is suitable for corrosion and protection of various carbon steels. The preparation process is safe, nontoxic, economical and reliable.

According to the invention, the nano sheet takes carbon steel as a substrate, and a uniform and compact nano sheet layer is formed on the surface of the carbon steel substrate through in-situ growth, and the nano sheet layer has excellent super-hydrophobic performance.

The nano-sheet structure prepared by the invention shows excellent super-hydrophobic property after low surface energy treatment, can reduce the contact area of water and the surface of carbon steel, slow down the corrosion rate to a certain extent, prolong the service life of steel, reduce the economic loss caused by corrosion, and has potential industrial application prospect in the aspects of self-cleaning, anti-icing, anti-fog, anti-snow, anti-drag and the like.

Drawings

FIG. 1 is a scanning electron microscope image of a nanosheet structure surface prepared in accordance with the present invention;

FIG. 2 is an X-ray diffraction pattern of the surface of a nanosheet structure prepared in accordance with the present invention;

FIG. 3 is a graph of contact angle and rolling angle of a nanosheet structure surface prepared in accordance with the present invention;

FIG. 4 is a self-cleaning behavior diagram of the superhydrophobic carbon steel surface prepared by the present invention.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides super-hydrophobic carbon steel in a first aspect, which comprises a carbon steel substrate and a nanosheet layer growing on the surface of the carbon steel substrate in situ, wherein a low-surface-energy substance is modified on the surface of the nanosheet layer.

In the present invention, the carbon steel is an iron-carbon alloy containing 0.0218 to 2.11 wt% of carbon, and generally contains a small amount of silicon, manganese, sulfur, phosphorus, etc. Carbon steels available in the art can be used to prepare the superhydrophobic carbon steel, such as N80 steel, Q235 steel, and # 45 steel.

In the invention, preferably, in the nanosheet layer, the nanosheets grow and are distributed on the surface of the carbon steel substrate along the direction of the 110 crystal plane in a two-dimensional plane, which can be seen by analyzing fig. 1.

Wherein the 110 crystal face belongs to the low-index crystal face of the carbon steel material.

Preferably, the thickness of the nanosheet layer is 20-50 nm.

In the invention, the size of the nano-sheet can be different according to different preparation processes, and preferably, the length of each nano-sheet is 0.2-1 μm, and the thickness is 20-50 nm.

As can also be seen from fig. 1, the width of the single nanosheet substantially exhibits a trend from wide to narrow in the direction from the substrate to away from the substrate, and preferably the width of the portion of the single nanosheet attached to the substrate is from 0.8 to 1.2 μm.

Preferably, the nanoplatelets comprise Fe, Fe₃O₄And optionally Fe₂O₃。

Preferably, the content of the Fe element in the nanosheet layer is 30-40 wt% and the content of the O element is 60-70 wt% based on the total amount of the Fe element and the O element.

In the invention, the surface of the nanosheet layer is modified with a low surface energy substance. The low surface energy substance is surface energy below 38mJ/m²Substances within the range.

Preferably, the low surface energy substance is at least one selected from the group consisting of silane-based low surface energy substances, fatty acid-based low surface energy substances, and paraffin wax.

The silane-based low-surface-energy substance may include an oxysilane-based low-surface-energy substance and/or a fluorosilane-based low-surface-energy substance, and preferably a fluorosilane-based low-surface-energy substance. In the preferred case, the superhydrophobic performance of the superhydrophobic carbon steel can be further improved.

The low surface energy material of the oxysilane group can be a common low surface energy material of the oxysilane group in the field, such as methyltrimethoxysilane, vinyltrimethoxysilane, hexadecyltrimethoxysilane and the like.

Among them, the fluorosilane-based low surface energy substance is preferably at least one member selected from fluorosilanes of F13-F17, and may be, for example, trimethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane, triethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane, tridecafluorooctyltrimethoxysilane, and tridecafluorooctyltriethoxysilane.

The fatty acid type low surface energy material may be a fatty acid type commonly used in the art, such as stearic acid.

The low surface energy substance is applied to the carbon steel substrate with the nano-sheet structure grown in situ by soaking or spraying, and the loading amount of the low surface energy substance is not particularly limited.

When the carbon steel product is prepared at the temperature (such as 350 ℃) below the temperature, the contact angle of the prepared carbon steel product is less than 150 degrees.

The above substances are commercially available and will not be described in detail.

The second aspect of the invention provides a method for preparing super-hydrophobic carbon steel, which comprises the following steps: and (3) sequentially carrying out pretreatment, in-situ growth of a nanosheet structure and low surface energy treatment on the carbon steel substrate to obtain the super-hydrophobic carbon steel.

The type and selection of the carbon steel substrate has been described in the first aspect and will not be described in detail herein.

Preferably, the method further comprises:

(1) pretreatment: etching the carbon steel base material to obtain an etched carbon steel base material;

(2) in-situ growth of the nanosheet structure: annealing the etched carbon steel substrate in an oxygen atmosphere to obtain the carbon steel substrate with the nano-sheet structure grown in situ;

(3) low surface energy treatment: and contacting the carbon steel substrate with the nano-sheet structure grown in situ with a low-surface-energy substance to obtain the super-hydrophobic carbon steel.

It should be understood that the carbon steel substrate may also be subjected to a desmear treatment prior to the etching treatment.

The mode of impurity removal can be an impurity removal method which is conventionally adopted in the field, so long as a carbon steel substrate with a clean surface can be obtained, and the impurity removal can be realized by grinding and/or cleaning treatment.

The polishing mode may be a polishing mode commonly known in the art, and different polishing devices or materials may be used for polishing, such as sandpaper, grinding wheel or polishing machine with different mesh numbers (preferably 320-600 mesh), etc.

The cleaning mode can be a common cleaning mode in the field, and preferably, the cleaning mode comprises ultrasonic cleaning of the carbon steel substrate to obtain the carbon steel substrate after the ultrasonic cleaning.

The ultrasonic cleaning may be performed in a cleaning solution commonly used in the art, including but not limited to at least one of ethanol, acetone, and methanol.

The time of the ultrasonic cleaning can be selected in a wide time, as long as impurities such as scrap iron on the surface of the carbon steel substrate can be removed.

In a preferred embodiment of the present invention, the impurity removal processing of the carbon steel substrate includes: polishing the carbon steel base material by using a polishing device or material with 320-mesh and 600-mesh, and then carrying out ultrasonic cleaning to obtain the carbon steel base material after impurity removal treatment.

In the invention, the carbon steel base material subjected to impurity removal treatment can be dried and then subjected to etching treatment to obtain the etched carbon steel base material.

Preferably, in the step (1), the etching manner includes: and (3) carrying out surface etching on the carbon steel base material subjected to impurity removal treatment by using inorganic acid to obtain the etched carbon steel base material.

The etching may be performed by immersing the carbon steel substrate in an inorganic acid, or by applying an inorganic acid to the surface of the carbon steel substrate, as long as the surface of the carbon steel substrate is brought into contact with the inorganic acid.

The inorganic acid is preferably nitric acid and/or sulfuric acid.

Preferably, the concentration of the inorganic acid is 1-5 wt%, and can be, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 wt%, and any range of compositions between any two values.

Preferably, the etching time is 3-5 min.

The carbon steel substrate after the etching treatment can be washed by water to remove residual inorganic acid, and then dried.

In the invention, the carbon steel substrate after etching treatment is annealed to obtain a carbon steel substrate with an in-situ grown nanosheet structure, preferably, in step (2), the annealing manner includes: heating the etched carbon steel substrate to 400-600 ℃ in an oxygen atmosphere, then annealing for 1-2h, and cooling to room temperature to obtain the carbon steel substrate with the in-situ growth nano-sheet structure.

The annealing may be carried out in equipment conventionally used in the art, for example, the annealing may be carried out in a tube furnace.

In the present invention, the oxygen atmosphere refers to an oxygen-containing atmosphere, the oxygen content of which can be selected within a wide range, and preferably, the oxygen content of the oxygen atmosphere is 80 to 100% by volume. Other components in the oxygen atmosphere may be nitrogen, carbon dioxide, and the like.

In the present invention, it is preferable that the temperature increase rate is 4 to 6 ℃/min.

During research, the inventors of the present invention found that the density and size of the nanosheets increase with increasing annealing temperature, such as the nanosheet structure shown in fig. 1 at annealing temperatures of 400, 450, 500 and 550 ℃. The nanosheet layer is black, and the nanosheets grow in the two-dimensional plane along the direction of the 110 crystal plane and are uniformly distributed on the surface of the carbon steel substrate. The size of the individual nanoplatelets is as described in the first aspect. Moreover, the different annealing temperatures allow the morphology of the iron element in the nanosheets to be different, for example, at an annealing temperature of 400 ℃ substantially no Fe is present₂O₃Form is shown. And as the temperature increases, Fe₂O₃Gradually increases.

In the present invention, the cooling mode may be natural cooling, or cooling at a specific rate (for example, may be 5 to 10 ℃/min).

In the present invention, room temperature means 25. + -. 5 ℃.

In the present invention, the carbon steel substrate with the nanosheet structure grown in situ is further subjected to a low surface energy treatment, preferably, the low surface energy treatment comprises: and contacting the carbon steel substrate with the nano-sheet structure grown in situ with a low-surface-energy substance to obtain the super-hydrophobic carbon steel.

In the step (3), the contact mode may be immersing the carbon steel substrate with the in-situ grown nanosheet structure in a low-surface-energy substance solution, or applying a low-surface-energy substance to the surface of the carbon steel substrate with the in-situ grown nanosheet structure.

Preferably, the contact time is 0.2 to 1 h.

The low surface energy substance has already been described in the first aspect and will not be described in detail here.

Preferably, the solvent of the low surface energy substance solution is selected from at least one of ethanol, acetone and methanol, more preferably ethanol.

Preferably, the low surface energy substance solution has a low surface energy substance content of 0.5 to 2 wt%.

In the invention, the carbon steel substrate subjected to low surface energy treatment can be further subjected to cleaning and drying treatment to obtain the super-hydrophobic carbon steel.

The solution for washing includes, but is not limited to, at least one of ethanol, acetone, methanol, and water.

The drying conditions may be selected from a wide range as long as they can be dried, and preferably, the drying conditions include: the temperature is 100 ℃ and 150 ℃, and the time is 0.5-2 h.

According to a particularly preferred embodiment of the present invention, the method for preparing the superhydrophobic carbon steel comprises: polishing, cleaning and etching the carbon steel substrate to obtain the etched carbon steel substrate, wherein the etching mode comprises the following steps: and etching the surface of the carbon steel base material subjected to impurity removal treatment by using inorganic acid to obtain the etched carbon steel base material. Heating the etched carbon steel substrate to 400-600 ℃ in an oxygen atmosphere, annealing for 1-2h, and then cooling to room temperature to obtain the carbon steel substrate with the in-situ growth nano-sheet structure. And contacting the carbon steel substrate with the nano-sheet structure grown in situ with a low-surface-energy substance to obtain the super-hydrophobic carbon steel. Wherein the low surface energy substance is a fluorosilane low surface energy substance.

A third aspect of the invention provides a superhydrophobic carbon steel prepared according to the method described above.

The structure and properties of the superhydrophobic carbon steel have been explained in the first aspect and will not be described in detail herein.

The present invention will be described in detail below by way of examples.

In the following examples, reagents and materials used were obtained commercially unless otherwise specified.

The annealing treatment was performed using pure oxygen as follows.

Example 1

This example illustrates the preparation of the superhydrophobic carbon steel of the present invention.

(1) Selecting 45# steel as a base material, polishing the surface of the carbon steel base material by using 500-mesh abrasive paper, then putting the base material into absolute ethyl alcohol for ultrasonic cleaning treatment, removing impurities such as scrap iron and the like on the surface, and drying the base material for later use.

(2) And (3) placing the carbon steel base material subjected to impurity removal into dilute nitric acid with the concentration of 3 weight percent for surface etching for 4min to obtain the etched carbon steel base material. And after etching is finished, taking out the substrate, washing away the residual dilute nitric acid on the surface by using deionized water, and drying.

(3) Placing the etched carbon steel base material in a tube furnace in O₂And carrying out annealing treatment in the atmosphere. The heating rate of the tube furnace is 5 ℃/min, the annealing temperatures are respectively 400, 450, 500 and 550 ℃, the annealing time is 1.5h, the tube furnace is naturally cooled to room temperature after annealing is finished, a layer of black nanosheet structure uniformly grows on the surface of the substrate, and the carbon steel substrate with the nanosheet structure in situ grows.

Referring to FIG. 1, wherein (a) is an SEM image of a sample wafer prepared at an annealing temperature of 400 ℃; (b) is SEM picture of sample wafer prepared with annealing temperature of 450 deg.C; (c) is SEM picture of sample wafer prepared with annealing temperature of 500 deg.C; (d) is an SEM picture of a sample wafer prepared with an annealing temperature of 550 ℃. As can be seen from the SEM image, the nano-sheets gradually increase along the direction of the 110 crystal plane in the two-dimensional plane and are uniformly distributed on the surface of the substrate along with the increase of the annealing temperature.

The composition of the resultant material was analyzed by X-ray diffraction, see fig. 2. (a) Is an XRD pattern of a sample wafer prepared at the annealing temperature of 400 ℃; (b) is an XRD pattern of a sample wafer prepared at the annealing temperature of 450 ℃; (c) is an XRD pattern of a sample wafer prepared at the annealing temperature of 500 ℃; (d) is the XRD pattern of a sample wafer prepared with an annealing temperature of 550 ℃. It can be seen from the graph that when the annealing temperature is 400 ℃, the surface of the sample wafer is basically composed of iron and Fe₃O₄Composition of Fe₂O₃Substantially absent; when the temperature is increased to 450 ℃, Fe gradually appears on the surface₂O₃With further increase in temperature, Fe₂O₃Gradually becomes stronger and Fe generated on the surface is formed₂O₃And the number of the steps is gradually increased.

(4) Putting the carbon steel substrate with the in-situ grown nanosheet structure into an ethanol solution of triethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane (the concentration of the triethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane is 0.8 wt%), soaking for 0.5H, taking out, washing for 2-3 times in absolute ethanol and deionized water, then putting into a drying oven for drying at the drying temperature of 120 ℃ for 1H, and obtaining the superhydrophobic carbon steel after drying.

Measuring the water rolling angle of the surface of the super-hydrophobic carbon steel, referring to fig. 3, because the water drops are difficult to stay on the surface of the super-hydrophobic carbon steel, the rolling angle is close to 0 degree, and (a) is a rolling angle graph of the water drops under the treatment condition of 400 ℃; (b) is a rolling angle diagram of water drops under the treatment condition of 450 ℃; (c) is a rolling angle diagram of water drops under the treatment condition of 500 ℃; (d) is a rolling angle diagram of water drops under the treatment condition of 550 ℃; the prepared super-hydrophobic carbon steel can be found to have excellent super-hydrophobicity.

The super-hydrophobic carbon steel prepared by the method has a regular nanosheet structure on the surface, and is combined with the modification of a low-surface-energy substance, so that water drops cannot stay on the surface of the carbon steel, the rolling angle (SA) of the carbon steel is close to 0 degree, and the carbon steel has very excellent super-hydrophobic performance.

After the prepared sample wafer is soaked in water, a silver mirror phenomenon occurs at a water-air interface, as shown in fig. 4 (a). The bouncing phenomenon that the water drops hit the surface thereof is shown in fig. 4 (b). The water jet ejection phenomenon is shown in fig. 4 (c).

The self-cleaning performance was further tested by placing the contaminants on the surface of the superhydrophobic carbon steel (left) and the surface of the blank coupon (right), respectively, as shown in fig. 4(d) for the initial state of the contaminant placement. After the water drop is dropped, the water drop on the surface of the super-hydrophobic carbon steel rolls over the part, and the pollutants are completely carried away by the water drop, but the pollutants on the surface of the blank test piece cannot be removed, as shown in fig. 4 (e). Therefore, the super-hydrophobic carbon steel prepared by the method has excellent super-hydrophobic performance.

Example 2

This example illustrates the preparation of the superhydrophobic carbon steel of the present invention.

(1) Selecting N80 steel as a base material, polishing the surface of the carbon steel base material by using 320-mesh sand paper, then putting the base material into absolute ethyl alcohol for ultrasonic cleaning treatment, removing impurities such as scrap iron on the surface, and drying for later use.

(2) And (3) putting the carbon steel base material subjected to impurity removal into dilute sulfuric acid with the concentration of 1 weight percent for surface etching for 5min to obtain the etched carbon steel base material. And after etching is finished, taking out the substrate, washing away the residual dilute nitric acid on the surface by using deionized water, and drying.

(3) Placing the etched carbon steel base material in a tube furnace in O₂And carrying out annealing treatment in the atmosphere. The temperature rise rate of the tube furnace is 4 ℃/min, the annealing temperature is 500 ℃, the annealing time is 1h, the tube furnace is naturally cooled to room temperature after the annealing is finished, a layer of black nanosheet structure uniformly grows on the surface of the substrate, and the carbon steel substrate with the nanosheet structure growing in situ is obtained.

The SEM image is similar to that of FIG. 1(c), and the XRD image is similar to that of FIG. 2 (c).

(4) Putting a carbon steel substrate with a nanosheet structure growing in situ into an ethanol solution of trimethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane (the concentration of the trimethoxy-1H, 1H,2H, 2H-heptadecafluorodecyl silane is 0.5 weight percent) to soak for 1H, taking out, washing for 2-3 times in absolute ethyl alcohol and deionized water, then putting into an oven to dry at the drying temperature of 120 ℃ for 1H, and obtaining the super-hydrophobic carbon steel after drying is completed.

Measuring the water rolling angle of the surface of the super-hydrophobic carbon steel, wherein the rolling angle is close to 0 degree because water drops are difficult to stay on the surface of the super-hydrophobic carbon steel; the prepared super-hydrophobic carbon steel has excellent super-hydrophobicity.

Example 3

This example illustrates the preparation of the superhydrophobic carbon steel of the present invention.

(1) Selecting Q235 steel as a base material, polishing the surface of the carbon steel base material by using 600-mesh sand paper, then putting the base material into absolute ethyl alcohol for ultrasonic cleaning treatment, removing impurities such as scrap iron and the like on the surface, and drying the base material for later use.

(2) And (3) placing the carbon steel base material subjected to impurity removal into dilute nitric acid with the concentration of 5 weight percent for surface etching for 3min to obtain the etched carbon steel base material. And after etching is finished, taking out the substrate, washing away the residual dilute nitric acid on the surface by using deionized water, and drying.

(3) Placing the etched carbon steel base material in a tube furnace in O₂And carrying out annealing treatment in the atmosphere. The temperature rise rate of the tube furnace is 6 ℃/min, the annealing temperature is 500 ℃, the annealing time is 2h, the tube furnace is naturally cooled to room temperature after the annealing is finished, a layer of black nanosheet structure uniformly grows on the surface of the substrate, and the carbon steel substrate with the nanosheet structure growing in situ is obtained.

The SEM image is similar to that of FIG. 1(c), and the XRD image is similar to that of FIG. 2 (c).

(4) The carbon steel substrate with the in-situ grown nanosheet structure is placed into an ethanol solution of tridecafluorooctyltrimethoxysilane (the concentration of tridecafluorooctyltrimethoxysilane is 2 weight percent) to be soaked for 0.2h, the carbon steel substrate is taken out and then washed in absolute ethanol and deionized water for 2-3 times, then the carbon steel substrate is placed into an oven to be dried, the drying temperature is 120 ℃, the drying time is 1h, and the super-hydrophobic carbon steel is obtained after the drying is completed.

Measuring the water rolling angle of the surface of the super-hydrophobic carbon steel, wherein the rolling angle is close to 0 degree because water drops are difficult to stay on the surface of the super-hydrophobic carbon steel; the prepared super-hydrophobic carbon steel has excellent super-hydrophobicity.

Example 4

This example illustrates the preparation of the superhydrophobic carbon steel of the present invention.

(1) Selecting 45# steel as a base material, polishing the surface of the carbon steel base material by using 500-mesh abrasive paper, then putting the base material into absolute ethyl alcohol for ultrasonic cleaning treatment, removing impurities such as scrap iron and the like on the surface, and drying the base material for later use.

(2) And (3) placing the carbon steel base material subjected to impurity removal into dilute nitric acid with the concentration of 8 weight percent for surface etching for 4min to obtain the etched carbon steel base material. And after etching is finished, taking out the substrate, washing away the residual dilute nitric acid on the surface by using deionized water, and drying.

(3) Placing the etched carbon steel base material in a tube furnace in O₂And carrying out annealing treatment in the atmosphere. The temperature rise rate of the tubular furnace is 8 ℃/min, the annealing temperature is 600 ℃, the annealing time is 1h, the material is naturally cooled to room temperature after the annealing is finished, a layer of black nanosheet structure uniformly grows on the surface of the substrate, and the carbon steel substrate with the nanosheet structure growing in situ is obtained.

The SEM image is similar to that of FIG. 1(d), the XRD image is similar to that of FIG. 2(d), and the content of O element is slightly higher.

(4) Putting the carbon steel substrate with the in-situ grown nanosheet structure into an ethanol solution of trimethoxy silane (the concentration of the trimethoxy silane is 0.8 wt%), soaking for 0.5h, taking out, washing for 2-3 times in absolute ethanol and deionized water, then putting into an oven for drying at the drying temperature of 120 ℃ for 1h, and obtaining the superhydrophobic carbon steel after drying.

Measuring the water rolling angle of the surface of the super-hydrophobic carbon steel, wherein the rolling angle is close to 0 degree because water drops are difficult to stay on the surface of the super-hydrophobic carbon steel; the prepared super-hydrophobic carbon steel has excellent super-hydrophobicity.

Example 5

This example illustrates the preparation of the superhydrophobic carbon steel of the present invention.

The operation is carried out according to the method described in example 1, except that the low surface energy substance is stearic acid, and the carbon steel substrate with the nanosheet structure grown in situ is placed into an ethanol solution of stearic acid (the concentration of stearic acid is 8mmol/L) to be soaked for 5h, so as to obtain the super-hydrophobic carbon steel.

Measuring the water rolling angle of the surface of the super-hydrophobic carbon steel, wherein the rolling angle is 2 degrees, and the contact angle is 152 degrees; the prepared super-hydrophobic carbon steel has excellent super-hydrophobicity.

Comparative example 1

The operation is carried out according to the method described in the embodiment 1, except that the carbon steel substrate after pretreatment is directly subjected to low surface energy treatment without in-situ growth of a nano-sheet structure, so as to obtain a carbon steel product.

As a result, the surface of the carbon steel product was found to be hydrophilic with a contact angle of 76 deg..

Comparative example 2

The operation was carried out according to the method described in example 1 (annealing temperature 500 ℃), except that the carbon steel substrate with the nanosheet structure grown in situ prepared in step (3) was directly obtained without low surface energy treatment.

As a result, the surface of the carbon steel product was found to be hydrophilic with a contact angle of 35 deg..

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.