Super-hydrophobic and high-corrosion-resistance coated steel rail and preparation method thereof

Abstract

The preparation method comprises the following steps that the rail web and the rail bottom of the steel rail are subjected to surface cleaning treatment so as to remove attachments such as surface grease, rust stains and oxide layers, and the pretreated steel rail is obtained; spraying is conducted on the surfaces of the rail waist and the rail bottom of the pretreated steel rail through an electric arc spraying technology, so that an alloy coating is formed on the surface of the pretreated steel rail, and the steel rail with the alloy coating is obtained; and spraying is conducted on the surface of the steel rail with the alloy coating through a spraying technology, so that the super-hydrophobic coating is formed on the surface of the alloy coating, and the super-hydrophobic and high-corrosion-resistance coated steel rail is obtained. The alloy coating is prepared on the surface of the steel rail by adopting an electric arc spraying process, and then the hole sealing treatment is performed on the surface of the alloy coating through the super-hydrophobic coating, so that the surface has super-hydrophobicity and has the advantages of high corrosion resistance, self-cleaning property and good wear resistance, and the service life of the steel rail can be greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of steel for rails, and more specifically, to a super hydrophobic-high corrosion-resistant coating rail and a preparation method thereof. Background Art

[0002] Rails are the core components of railway track structures, and their quality is crucial to the safety, stability and high-speed operation of trains. At present, high-speed railway tracks around the world generally face the problem of short service life, and corrosion is the most important influencing factor. Rail corrosion problems are usually caused by a variety of factors, including atmospheric environment, mechanical stress and stray current, and are mainly manifested as surface rust, cross-sectional corrosion loss, and foot fatigue failure, the latter of which accounts for up to 50% of rail break accidents. Atmospheric corrosion and stress damage are the main causes of rail failure. In order to cope with the corrosion problems of tunnel railways, undersea tunnels and railways in coastal areas, research organizations at home and abroad have conducted extensive research and explored a variety of rail anti-corrosion technologies.

[0003] Among them, thermal spraying metal coating technology is considered to be an economical and efficient anti-corrosion method, but there are the following problems in its application process: (1) The currently reported thermal spraying processes such as supersonic spraying and flame spraying have the problems of high noise, high cost, complex equipment and facilities, and it is difficult to achieve on-site rail surface online treatment; (2) Common alloy coatings obtained by thermal spraying metal coating technology have the problem of poor corrosion resistance, such as pure aluminum coatings have large porosity and easy corrosion perforation, pure zinc coatings have high electrochemical activity and fast coating consumption; (3) Due to its special preparation process, thermal spray coatings usually have a certain porosity. In order to improve the corrosion resistance of metal coatings, organic coatings (such as epoxy primers, topcoats, etc.) are usually used for post-sealing treatment. A large amount of organic solvents are volatilized during the preparation process, which does not meet the requirements of green environmental protection. In addition, most organic coatings have poor wear resistance and are easily contaminated by soil and dust in the natural environment. These pollutants adhere to the surface of the rails, which will aggravate the corrosion of the rails and make it difficult to meet actual needs.

[0004] Based on the above problems, it is urgent to develop an environmentally friendly, low-cost, self-cleaning, high-corrosion-resistant coated rail for use in the field of rail transportation. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art, provide a super hydrophobic-high corrosion resistant coated rail and a preparation method thereof, and the method of the present invention can effectively solve the serious corrosion problems currently faced by rails at the rail bottom and rail waist. In addition, the method can also significantly improve the organic solvent volatilization problem existing in the traditional coating process, reduce environmental pollution, and effectively improve the wear resistance of the coating while being economical and environmentally friendly. The introduction of the self-cleaning surface further optimizes the anti-pollution ability of the surface of the rail material, thereby significantly reducing the risk of electrochemical corrosion, and has a wide range of application prospects.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing a super hydrophobic-high corrosion-resistant coating rail comprises the following steps:

[0008] (1) Cleaning the rail waist and rail bottom of the rail to remove surface grease, rust stains, oxide layer and other attachments to obtain a pretreated rail;

[0009] (2) spraying the rail waist and rail bottom surfaces of the pretreated steel rail by an arc spraying process to form an alloy coating on the surface of the pretreated steel rail, thereby obtaining a steel rail with an alloy coating;

[0010] (3) A spraying process is used to spray the surface of the steel rail having the alloy coating to form a super-hydrophobic coating on the surface of the alloy coating, thereby obtaining the super-hydrophobic-high corrosion-resistant coated steel rail.

[0011] Optionally, in step (1), the surface cleaning treatment specifically includes: mechanical rust removal and surface roughening by sandblasting. After the treatment, the surface cleanliness of the rail waist and rail bottom of the rail is Sa3 level and the roughness is 70um to 120um.

[0012] Optionally, in step (2), the arc spraying process has a coating voltage of 25V to 30V, a spraying current of 160A to 200A, a wire feeding speed of 3m / min to 8m / min, a spraying pressure of 0.3Mpa to 0.7Mpa, and a spray gun moving speed of 200mm / s to 600mm / s.

[0013] Optionally, in step (2), the alloy coating is an alloy layer doped with rare earth elements.

[0014] Optionally, the alloy coating has a thickness of 120 μm to 300 μm.

[0015] Optionally, the thickness of the alloy coating includes but is not limited to 120 μm, 150 μm, 200 μm, 250 μm, 280 μm, 300 μm, etc.

[0016] Optionally, the rare earth element includes one or more of lanthanum, cerium and erbium.

[0017] Optionally, the alloy layer includes one of a zinc-aluminum-magnesium alloy coating, a zinc-aluminum alloy coating, an aluminum-zinc alloy coating and a pure aluminum alloy coating.

[0018] Optionally, when the alloy coating is a zinc-aluminum-magnesium alloy coating doped with rare earth elements, the alloy coating composition is Al: 1% to 13%, Mg: 1% to 3%, RE: 0.01% to 0.2%, and the rest is Zn and unavoidable impurities.

[0019] Optionally, when the alloy coating is a zinc-aluminum alloy coating doped with rare earth elements, the composition of the alloy coating is Al: 50% to 15%, Zn: 50% to 85%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities.

[0020] Optionally, when the alloy coating is an aluminum-zinc alloy coating doped with rare earth elements, the composition of the alloy coating is Al: 50% to 85%, Zn: 50% to 15%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities.

[0021] Optionally, when the alloy coating is a pure aluminum alloy coating doped with rare earth elements, the composition of the alloy coating is: Al: 99.0% to 99.9%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities.

[0022] Optionally, in step (3), the super-hydrophobic coating comprises the following components in parts by weight: 20 to 30 parts of acrylic resin, 2 to 4 parts of amino resin, 1 to 4 parts of polyisocyanate, 1.5 to 3 parts of nano-magnesium aluminum hydrotalcite, 2 to 3 parts of microcrystalline cellulose, 0.75 to 1.5 parts of octadecyltrimethoxysilane, 0.25 to 1 part of silane coupling agent, 5 to 10 parts of isopropanol, and 20 to 30 parts of anhydrous ethanol.

[0023] Optionally, the nano magnesium aluminum hydrotalcite has a particle size of 2 μm to 4 μm and a thickness of 30 nm to 50 nm;

[0024] Optionally, the particle size of the microcrystalline cellulose is 20 nm to 50 nm, and the length is >2 μm.

[0025] Optionally, in step (3), the spraying pressure in the spraying process is 0.3Mpa to 0.5Mpa, and the vertical distance between the spray gun nozzle and the substrate surface is 25cm to 30cm.

[0026] Optionally, the super hydrophobic coating has a thickness of 20 μm to 60 μm.

[0027] Optionally, the thickness of the super hydrophobic coating includes but is not limited to 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, etc.

[0028] The present invention also discloses a super-hydrophobic-high corrosion-resistant coating steel rail prepared by the above-mentioned preparation method.

[0029] Implementing the embodiments of the present invention will have the following beneficial effects:

[0030] 1. The present invention adopts an arc spraying process to prepare an alloy coating on the surface of a rail, and then seals the surface of the alloy coating with a super-hydrophobic coating. The surface has super-hydrophobicity, high corrosion resistance, self-cleaning, and good wear resistance. The service life of the rail can be greatly extended and can be applied to the field of rail transportation. Therefore, it has very significant social and economic benefits.

[0031] 2. The present invention adopts an economical arc spraying process to prepare an alloy coating on the rail surface. The alloy coating is directly bonded to the substrate with high strength, providing good adhesion and durability. The process is simple and fast, convenient for on-site online construction, and suitable for large-area outdoor applications.

[0032] 3. In the surface sealing treatment of the alloy coating, the present invention innovatively forms a hard "brick-mud" secondary micro-nano structure by adding nano magnesium-aluminum hydrotalcite with a rigid lamellar structure and microcrystalline cellulose with a flexible fibrous structure in the coating, which greatly improves the surface wettability, enhances the mechanical properties of the coating, and improves the wear resistance of the coating, so that the coated rail has super hydrophobicity, self-cleaning and good wear resistance.

[0033] 4. The magnesium-aluminum hydrotalcite in the present invention has anion exchange capacity and can exchange anions with various corrosive media. Microcrystalline cellulose has poor water-air permeability and strong barrier properties. The introduction of functional micro-nano materials greatly enhances the corrosion resistance of the coating. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0035] Example 1

[0036] (1) Pretreatment of rails: In order to make the coating adhere effectively to the rails, the rail waist and rail bottom are cleaned and pretreated to remove surface grease, rust stains, oxide layer and other attachments. Sandblasting is used for mechanical rust removal and surface roughening. After treatment, the surface cleanliness of the rail waist and rail bottom is Sa3 and the roughness is 107um.

[0037] (2) The arc spraying process is used to spray a zinc-aluminum alloy coating doped with lanthanum on the waist and bottom of the pretreated rail. The arc spraying process parameters are: spraying voltage 26V, spraying current 180A, wire feeding speed 5m / min, spraying pressure 0.4Mpa, spray gun moving speed 400mm / s, and the thickness of the alloy coating is 126μm. Among them, the zinc-aluminum alloy coating composition is: Al: 15%, Zn: 85%, RE: 0.01%, and the rest are unavoidable impurities.

[0038] (3) Prepare a super hydrophobic coating, the components of which are, by weight percentage, 25 parts of acrylic resin, 3 parts of amino resin, 1 part of polyisocyanate, 1.5 parts of nano magnesium aluminum hydrotalcite (particle size of 3 μm, thickness of 30 nm), 2 parts of microcrystalline cellulose (particle size of 30 nm, length>2 μm), 0.75 parts of octadecyltrimethoxysilane, 0.25 parts of silane coupling agent, 8 parts of isopropanol, and 25 parts of anhydrous ethanol.

[0039] (4) A super-hydrophobic coating is sprayed on the surface of the alloy coated rail by a spraying process. The spraying pressure in the spraying process is 0.3 MPa, the vertical distance between the spray gun nozzle and the substrate surface is 30 cm, and the coating is cured at room temperature. After the holes are sealed, the thickness of the super-hydrophobic coating is 30 μm, and a super-hydrophobic and highly corrosion-resistant coated rail is obtained.

[0040] Example 2

[0041] Compared with Example 1, the present embodiment is different in that: in step (2) of the present embodiment, the arc spraying process is used to spray the zinc-aluminum-magnesium alloy coating doped with cerium on the waist and bottom of the pretreated steel rail, and the arc spraying process parameters are: spraying voltage 28V, spraying current 180A, wire feeding speed 5m / min, spraying pressure 0.5Mpa, spray gun moving speed 500mm / s, and alloy coating thickness 125μm. Among them, the alloy coating composition is: Al: 11%, Mg: 3%, RE: 0.01%, and the rest is Zn and unavoidable impurities.

[0042] Example 3

[0043] The present embodiment is different from the embodiment 1 in that: in step (3) of the present embodiment, the components by weight percentage are 25 parts of acrylic resin, 2 parts of amino resin, 1.5 parts of polyisocyanate, 2 parts of nano magnesium aluminum hydrotalcite (particle size is 3 μm, thickness is 30 nm), 2 parts of microcrystalline cellulose (particle size is 30 nm, length>2 μm), 1 part of octadecyltrimethoxysilane, 0.7 parts of silane coupling agent, 8 parts of isopropanol, and 25 parts of anhydrous ethanol.

[0044] Example 4

[0045] Compared with Example 1, the present embodiment differs in that: in step (4) of the present embodiment, the spraying pressure in the spraying process is 0.4 MPa, the vertical distance between the spray gun nozzle and the substrate surface is 30 cm, the coating is cured at room temperature, and the hole is sealed after treatment. The thickness of the super-hydrophobic coating is 40 μm, and a super-hydrophobic, highly corrosion-resistant coated rail is obtained.

[0046] Comparative Example 1

[0047] The only difference between this comparative example and Example 1 is that nano-magnesium aluminum hydrotalcite and microcrystalline cellulose are not added in step (3) of this comparative example.

[0048] Comparative Example 2

[0049] The only difference between this comparative example and Example 1 is that the rails in this comparative example are not processed in step (4).

[0050] Table 1 Test results of water contact angle on sample surface

[0051] serial number Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Water contact angle 158°±1.7° 161°±2.3° 159°±1.2° 163°±0.9° 128°±0.8° 93.6°±2.1°

[0052] Table 2 Results of accelerated corrosion test of samples in neutral 5% NaCl salt spray

[0053]

[0054] The surface water contact angle test and corrosion resistance test are carried out on the rails prepared in Example 1-Example 4 and Comparative Example 1-2. The results are shown in Table 1-Table 2. The corrosion resistance of Examples 1-4 of the present invention is better than that of the comparative example, indicating that the present invention adopts an arc spraying process to prepare an alloy coating on the surface of the rail, and then the alloy coating surface is sealed by a super-hydrophobic coating. The surface has super-hydrophobicity, high corrosion resistance, self-cleaning, and good wear resistance, which can greatly extend the service life of the rail. The super-hydrophobic coated rail prepared by the method of the present invention has excellent corrosion resistance and self-cleaning, and can be applied to the field of rail transportation, so it has very significant social and economic benefits.

[0055] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a super hydrophobic-high corrosion-resistant coating rail, characterized in that: The following steps are involved: (1) Cleaning the rail waist and rail bottom of the rail to remove surface grease, rust stains, oxide layer and other attachments to obtain a pretreated rail; (2) spraying the rail waist and rail bottom surfaces of the pretreated steel rail by an arc spraying process to form an alloy coating on the surface of the pretreated steel rail, thereby obtaining a steel rail with an alloy coating; (3) A spraying process is used to spray the surface of the steel rail having the alloy coating to form a super-hydrophobic coating on the surface of the alloy coating, thereby obtaining the super-hydrophobic-high corrosion-resistant coated steel rail.

2. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 1, characterized in that: In step (1), the surface cleaning treatment specifically includes: mechanical rust removal and surface roughening by sandblasting. After the treatment, the surface cleanliness of the rail waist and rail bottom of the rail is Sa3 level and the roughness is 70um to 120um.

3. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 1, characterized in that: In step (2), the arc spraying process has a spraying voltage of 25V to 30V, a spraying current of 160A to 200A, a wire feeding speed of 3m / min to 8m / min, a spraying pressure of 0.3Mpa to 0.7Mpa, and a spray gun moving speed of 200mm / s to 600mm / s.

4. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 1, characterized in that: In step (2), the alloy coating is an alloy layer doped with a rare earth element; The thickness of the alloy coating is 120 μm to 300 μm.

5. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 4, characterized in that: The rare earth element includes one or more of lanthanum, cerium and erbium; The alloy layer includes one of a zinc-aluminum-magnesium alloy coating, a zinc-aluminum alloy coating, an aluminum-zinc alloy coating and a pure aluminum alloy coating.

6. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 5, characterized in that: In step (2), when the alloy coating is a zinc-aluminum-magnesium alloy coating doped with rare earth elements, the alloy coating composition is Al: 1% to 13%, Mg: 1% to 3%, RE: 0.01% to 0.2%, the rest is Zn and unavoidable impurities; When the alloy coating is a zinc-aluminum alloy coating doped with rare earth elements, the alloy coating composition is Al: 50% to 15%, Zn: 50% to 85%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities; When the alloy coating is an aluminum-zinc alloy coating doped with rare earth elements, the alloy coating composition is Al: 50% to 85%, Zn: 50% to 15%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities; When the alloy coating is a pure aluminum alloy coating doped with rare earth elements, the alloy coating composition is: Al: 99.0% to 99.9%, RE: 0.01% to 0.1%, and the rest are unavoidable impurities.

7. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 1, characterized in that: In step (3), the super-hydrophobic coating comprises the following components in parts by weight: 20 to 30 parts of acrylic resin, 2 to 4 parts of amino resin, 1 to 4 parts of polyisocyanate, 1.5 to 3 parts of nano magnesium aluminum hydrotalcite, 2 to 3 parts of microcrystalline cellulose, 0.75 to 1.5 parts of octadecyltrimethoxysilane, 0.25 to 1 part of silane coupling agent, 5 to 10 parts of isopropyl alcohol, and 20 to 30 parts of anhydrous ethanol.

8. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 7, characterized in that: The nano magnesium aluminum hydrotalcite has a particle size of 2 μm to 4 μm and a thickness of 30 nm to 50 nm; The particle size of the microcrystalline cellulose is 20nm-50nm, and the length is greater than 2μm.

9. The method for preparing a super hydrophobic-high corrosion resistant coating rail according to claim 1, characterized in that: In step (3), the spraying pressure in the spraying process is 0.3Mpa to 0.5Mpa, and the vertical distance between the spray gun nozzle and the substrate surface is 25cm to 30cm; The thickness of the super hydrophobic coating is 20 μm to 60 μm.

10. A super-hydrophobic-high corrosion-resistant coated steel rail prepared by the preparation method according to any one of claims 1 to 9.

Images