阅读说明：本技术 一种兼具疏水和耐磨性的复合涂层、制备方法及应用 (Composite coating with hydrophobic property and wear resistance, preparation method and application ) 是由 朱丽娜 岳�文 邵晓燕 康嘉杰 王海斗 马国政 邢志国 王成彪 付志强 田斌 佘 于 2020-05-12 设计创作，主要内容包括：本发明属于高分子化学材料技术领域,提供了一种兼具疏水和耐磨性的复合涂层,它是二氧化铈分散于聚四氟乙烯中形成的复合涂层,复合涂层的厚度范围为20-40μm；复合涂层中二氧化铈的含量按质量份计为1-15份,二氧化铈的粒度范围为100nm-2μm；聚四氟乙烯的含量按质量份计为85-99份。该复合涂层的制备方法为：将待涂覆表面(比如冰层取芯钻具的切削刃及钻头体表面)进行喷砂处理以去除表面氧化层,使表面具有一定的清洁度和粗糙度,改善机械性能并提高与涂层之间的附着力；将二氧化铈粉末分散到聚四氟乙烯水乳液中,然后利用表面工程技术在待涂覆工件表面获得兼具疏水和耐磨性的二氧化铈/聚四氟乙烯复合涂层。(The invention belongs to the technical field of high molecular chemical materials, and provides a composite coating with hydrophobicity and wear resistance, which is a composite coating formed by dispersing cerium dioxide in polytetrafluoroethylene, wherein the thickness range of the composite coating is 20-40 mu m; the content of cerium dioxide in the composite coating is 1-15 parts by mass, and the particle size range of the cerium dioxide is 100nm-2 mu m; the content of the polytetrafluoroethylene is 85-99 parts by mass. The preparation method of the composite coating comprises the following steps: the surface to be coated (such as the cutting edge of an ice layer core drill and the surface of a drill body) is subjected to sand blasting treatment to remove a surface oxide layer, so that the surface has certain cleanliness and roughness, the mechanical property is improved, and the adhesion between the surface to be coated and the coating is improved; the cerium dioxide powder is dispersed into polytetrafluoroethylene aqueous emulsion, and then a surface engineering technology is utilized to obtain the cerium dioxide/polytetrafluoroethylene composite coating with both hydrophobicity and wear resistance on the surface of a workpiece to be coated.)

1. A composite coating with both hydrophobicity and wear resistance is characterized by comprising polytetrafluoroethylene and cerium dioxide uniformly dispersed in the polytetrafluoroethylene, wherein the thickness of the composite coating ranges from 20 to 40 microns;

the content of cerium dioxide in the composite coating is 1-15 parts by mass, and the particle size range of the cerium dioxide is 100nm-2 mu m;

the content of the polytetrafluoroethylene is 85-99 parts by mass.

2. The method of claim 1, wherein the method comprises the steps of:

1) preparing the coating: adding cerium dioxide powder into aqueous emulsion of polytetrafluoroethylene, and dispersing for 15min-30min to be uniform by using a sand mill at the temperature of 40 ℃ to obtain a coating;

2) surface pretreatment of the workpiece to be coated: firstly, dissolving grease on the surface of a workpiece to be coated by using an organic solvent, heating to about 300-400 ℃ to volatilize the grease, cleaning the surface of the workpiece to be coated by adopting sand blasting treatment, enabling the surface to obtain certain roughness, and improving the binding capacity of a coating and the surface of the workpiece;

3) spraying: loading the coating obtained in the step 1) into a spray gun, and uniformly spraying the coating on the surface of a workpiece to be coated by using the spray gun;

4) and (3) drying: putting the workpiece coated with the composite coating in the step 3) into a drying oven, and drying for 10-20 min at 100-120 ℃;

5) and (3) sintering: and (3) placing the workpiece coated with the composite coating and dried in the step 4) into a box-type curing furnace for curing treatment, gradually heating from room temperature to 350-390 ℃ within 40-50min, then sintering at constant temperature for 20-30min, and cooling in air to obtain the composite coating.

3. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: the mass percentage of the polytetrafluoroethylene in the aqueous emulsion of the polytetrafluoroethylene in the step 1) is 60 percent.

4. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: in the coating obtained in the step 1), 95 parts by mass of polytetrafluoroethylene and 5 parts by mass of cerium dioxide are added; the particle size of the cerium oxide is 500 nm.

5. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: in the step 3), the pressure of a spray gun is 0.3-0.4MPa in the spraying process, the distance between a gun mouth and a workpiece to be coated is 20-25cm, and the spraying angle is 45 degrees.

6. The method of preparing the composite coating layer having both hydrophobic and abrasion resistance according to claim 2 or 5, wherein: in the step 3), the pressure of a spray gun is 0.3MPa, the distance between a gun mouth and the workpiece is 20cm, and the spraying angle is 45 degrees.

7. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: the dispersing time of the sand mill in the step 1) is 20 min; the temperature for volatilizing the grease in the step 2) is 400 ℃.

8. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: and (3) drying the workpiece coated with the composite coating in the step 4) in a drying oven at 100 ℃ for 10 min.

9. The method of preparing the hydrophobic and abrasion resistant composite coating of claim 2, wherein: in the step 5), the mechanism for curing the workpiece coated with the composite coating in the box-type curing furnace is as follows: gradually heating to 360 ℃ within 40min, then sintering at constant temperature for 20min, and cooling in air to obtain the composite coating.

10. The use of the hydrophobic and wear resistant composite coating of claim 1 on an ice core drilling tool, wherein: the composite coating with both hydrophobicity and wear resistance is applied to the surface of a cutting edge and/or a bit body of an ice core drilling tool.

Technical Field

The invention relates to the technical field of high molecular chemical materials, in particular to a composite coating with hydrophobic property and wear resistance, a preparation method and application.

Background

The polar region scientific and technical research aims to explore the earth system and the change thereof, and the polar region ice layer contains a large amount of development history information, the history and the law of the change of the earth climate, and the information is an important basis for predicting and coping with the change of the global climate.

Some important scientific problems still exist in the drilling technology for obtaining the polar ice core, and one of the problems is that when a core drill drills a warm ice layer, the cutting tool and the bit body part are frozen, so that the drilling efficiency and the equipment safety are seriously influenced. The traditional method of using ethanol water solution or coating Teflon coating only partially improves the problem, and the drilling efficiency is still low.

The surface of the drilling tool is provided with the coating with both hydrophobicity and wear resistance, the surface of the drilling tool is not stained with water or is stained with less water through the hydrophobic coating so as to solve the problem of icing, and meanwhile, the coating has high wear resistance and provides support for ensuring the efficiency of drilling an ice layer, so that the problems of icing and drilling efficiency generated at the positions of the cutting tool and the bit body can be fundamentally solved.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a composite coating with hydrophobicity and wear resistance, a preparation method and application thereof.

The invention has the technical scheme that the composite coating with both hydrophobicity and wear resistance comprises polytetrafluoroethylene and cerium dioxide uniformly dispersed in the polytetrafluoroethylene, and the thickness range of the composite coating is 20-40 mu m; the content of cerium dioxide in the composite coating is 1-15 parts by mass, and the particle size range of the cerium dioxide is 100nm-2 mu m; the content of the polytetrafluoroethylene is 85-99 parts by mass.

Polytetra fluoroethylene (abbreviated as PTFE) hydrophobic coating has low surface energy, but pure PTFE coating has low hardness and poor wear resistance, and the introduction of cerium dioxide (Ceria) can prepare hydrophobic wear-resistant composite coating. The cerium dioxide has a unique electronic structure, so that the cerium dioxide has intrinsic hydrophobicity, high hardness and excellent tensile resistance, is compounded with polytetrafluoroethylene, and improves the wear resistance of the coating while further improving the hydrophobicity.

The invention carries out compound treatment on the polytetrafluoroethylene, uses cerium dioxide to modify the polytetrafluoroethylene, and then utilizes the surface engineering technology to prepare the composite coating, and the coating has hydrophobicity and wear resistance. Because of the hydrophobicity, water drops or water vapor are not easy to adhere to the surface of the coating, so that the possibility of icing is reduced, and in the application of high hydrophobicity or anti-icing requirement and wear resistance requirement, the cerium dioxide/polytetrafluoroethylene composite coating with excellent wear resistance and hydrophobicity can meet the requirement, and the icing phenomenon of a cutting tool and a drill bit body part when a core drill drills a warm ice layer can be effectively solved.

When the mass part of the cerium dioxide is more than 15 parts, the coating material is easy to disperse unevenly, and the coating cracks during sintering; when the mass part of cerium oxide is less than 1 part, the addition of cerium oxide does not significantly improve the hydrophobicity of the coating.

After the over-thick composite coating is sintered, the cracking phenomenon is easy to occur, and the over-thin coating is easy to wear through under the working environment, so that the performances of hydrophobic anti-icing and the like are lost, therefore, the thickness range of the composite coating is designed to be 20-

40μm。

The invention also provides a preparation method of the composite coating with hydrophobic property and wear resistance, which comprises the following steps:

1) preparing the coating: adding cerium oxide powder to a polytetrafluoroethylene aqueous emulsion at 40 deg.C

Dispersing for 15min-30min to be uniform by using a sand mill to obtain a coating; wherein the aqueous emulsion of polytetrafluoroethylene is obtained by dispersing polytetrafluoroethylene in water;

2) surface pretreatment of the workpiece to be coated: firstly, dissolving grease on the surface of a workpiece to be coated by using an organic solvent, heating to about 300-400 ℃ to volatilize the grease, cleaning the surface of the workpiece to be coated by adopting sand blasting treatment, enabling the surface to obtain certain roughness, and improving the binding capacity of a coating and the surface of the workpiece;

3) spraying: loading the coating obtained in the step 1) into a spray gun, and uniformly spraying the coating on the surface of a workpiece to be coated by using the spray gun;

4) and (3) drying: putting the workpiece coated with the composite coating in the step 3) into a drying oven, and drying for 10-20 min at 100-120 ℃;

5) and (3) sintering: and (3) placing the workpiece coated with the composite coating and dried in the step 4) into a box-type curing furnace for curing treatment, gradually heating from room temperature to 350-390 ℃ within 40-50min, then sintering at constant temperature for 20-30min, and cooling in air to obtain the composite coating.

The method comprises the first step of carrying out sand blasting treatment on the surface of a workpiece to be coated to remove a surface oxide layer, so that the surface of the workpiece to be coated obtains certain cleanliness and roughness, the mechanical property of the workpiece to be coated is improved, and the bonding force between the coating to be coated and the surface of the workpiece is improved.

Secondly, dissolving surface grease in the surface pretreatment of the workpiece to be coated, so that the phenomena of poor adhesion of a coating, shrinkage and the like can be avoided; and then, the surface of the workpiece is cleaned by adopting sand blasting treatment and obtains certain roughness, so that the bonding capacity of the coating and the surface of the workpiece can be further improved.

In the fifth step, if the sintering temperature is higher than 400 ℃, the polytetrafluoroethylene is easy to decompose, so that the temperature range in which the polytetrafluoroethylene is in a molten state but does not generate chemical reaction to influence the structure is selected; with respect to the sintering time, if the sintering time is less than 20min, the coating is not firmly bonded to the substrate, and the crystallinity of PTFE is small and the roughness of the coating is low.

The microstructure of the prepared cerium dioxide modified polytetrafluoroethylene composite coating is a compact network structure, so that the fine network structure and cerium dioxide particles with excellent tensile resistance exist, the wear resistance of the coating is improved, and the coating is uniformly dispersed; the macroscopic surface is uniform micron-sized protrusions, which results in the roughness of the coating, and the protrusions are generated by the agglomeration of polytetrafluoroethylene crystals due to the sintering temperature and the sintering time of the coating, so that the sintering time is increased, the crystallinity is increased, the more obvious and denser the protrusions are, and the increased roughness is beneficial to the improvement of hydrophobicity.

Further, the mass percent of the polytetrafluoroethylene in the aqueous emulsion of the polytetrafluoroethylene in the step 1) is 60 percent, and the solvent is water; namely, 85 to 99 parts by mass of polytetrafluoroethylene corresponds to 165 parts by mass of an aqueous polytetrafluoroethylene emulsion in which the aqueous solvent is evaporated in the subsequent treatment step and the original parts by mass of polytetrafluoroethylene are mixed with cerium oxide to form the main component of the coating.

Further, 95 parts by mass of polytetrafluoroethylene and 5 parts by mass of cerium dioxide are contained in the coating obtained in the step 1); the particle size of the cerium oxide is 500 nm.

Further, in the step 3), the pressure of the spray gun is 0.3-0.4MPa in the spraying process, the distance between the gun mouth and the workpiece to be coated is 20-25cm, and the spraying angle is 45 degrees.

The coating can be atomized under the pressure, and the coating is easy to uniformly disperse on the surface of the substrate.

Further, in the step 3), the pressure of the spray gun is 0.3MPa, the distance between the gun opening and the workpiece is 20cm, and the spraying angle is 45 degrees.

Further, the dispersing time of the sand mill in the step 1) is 20 min; the temperature for volatilizing the grease in the step 2) is 400 ℃.

Further, the workpiece coated with the composite coating in the step 4) is placed in a drying oven and dried for 10min at 100 ℃.

Further, in the step 5), the mechanism of curing the workpiece coated with the composite coating in the box-type curing furnace is as follows: gradually heating to 360 ℃ within 40min, then sintering at constant temperature for 20min, and then cooling in air to obtain the composite coating.

The invention also provides the application of the composite coating with the hydrophobic property and the wear resistance on the ice core drilling tool, and the composite coating with the hydrophobic property and the wear resistance is applied to the surface of a cutting edge and/or a bit body of the ice core drilling tool.

Due to the low surface energy component and the micro-nano coarse structure of the super-hydrophobic surface, the freezing of water drops on the surface can be effectively delayed, the adhesion force can be reduced, and the super-hydrophobic surface has excellent anti-icing and anti-icing performances. Therefore, the ice-removing device can be used for improving the phenomenon that the cutting tool and the bit body part are iced when the core drill drills into a warm ice layer.

The invention has the advantages and beneficial effects that:

1) in the composite coating of the present invention: ceria, being a lanthanide oxide, has an intrinsic hydrophobicity of 5s²p⁶The 8-position electrons of the orbitals completely shield the 4f orbitals, so the tendency for electron exchange and hydrogen bond formation is reduced, and secondly they are able to adsorb hydrocarbons on the surface; the polytetrafluoroethylene has lower surface energy, so that the hydrophobic anti-icing performance of the coating is greatly improved.

2) According to the dispersion mode of the coating components, the proper sintering temperature and the proper sintering time, the micro-nano cerium dioxide is dispersed in the polytetrafluoroethylene aqueous emulsion to form the composite coating, the micro-morphology of the composite coating is a fine grid structure, and the macro-morphology of the composite coating is represented as a surface with micro-nano protrusions. The micro-nano cerium dioxide is filled and attached to the net structure of the polytetrafluoroethylene, so that the microstructure of the polytetrafluoroethylene is enhanced, the effect of reducing friction can be achieved, and the wear resistance of the PTFE coating is effectively improved.

3) In the preparation method, the preparation process of the coating is simple and controllable, the preparation method of the hydrophobic coating by the one-step spraying method comprises five main steps of dispersion, sand blasting, spraying, sintering and cooling, compared with an electrochemical deposition method, an etching method and the like, the spraying method is simple and easy to operate, a workpiece can be directly sprayed by adopting a spray gun, the preparation period is short, the cost is low, the assembly of the workpiece is not influenced, and the preparation method can be widely applied to engineering.

4) Compared with a pure PTFE coating, the contact angle of the 5 percent Ceria/PTFE composite coating is improved to 134 degrees from 114 degrees, and the wear rate is improved to 2.00 × 10 degrees^-4mm³Reduction of/Nm to 0.39 × 10^-4mm³/NmThe wear rate is reduced by 80.6%.

5) The composite coating has excellent hydrophobic anti-icing property and wear resistance, is applied to the surface of a cutting edge and/or a drill bit body of an ice core drilling tool, and can effectively solve the problems of drill bit icing and service durability.

Detailed Description

The present invention will be described in further detail below with reference to specific embodiments in order to make the present invention better understood by those skilled in the art.