Corrosion-resistant coating for vacuum working condition as well as preparation method and application of corrosion-resistant coating

Abstract

The invention belongs to the technical field of functional materials, and relates to a shielding coating, in particular to a corrosion-resistant coating for a vacuum working condition as well as a preparation method and application thereof. The coating is formed by compounding resin, filler, auxiliaries and an organic solvent, the mass ratio of the resin to the filler to the auxiliaries is (10-12): (3-5): (4-7), and the dosage of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluorine-carbon-silicon high-molecular polymer obtained by mixing 40-50 parts by weight of fluorocarbon resin and 5-10 parts by weight of organic silicon modified acrylic resin. The corrosion-resistant coating for the vacuum working condition has the advantages of high temperature resistance, oxidation stability, high adhesive force, high corrosion resistance, excellent cold and hot impact stability and the like, and the problem that the service life of a spacecraft is shortened due to radiation, atomic oxygen and temperature in a space environment at present can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials and relates to corrosion-resistant coatings, and in particular to a corrosion-resistant coating for vacuum working conditions and a preparation method and application thereof. Background Art

[0002] Shielding coating is a coating that is applied to the surface of a substrate and can produce a corresponding effect. When a spacecraft is in a vacuum, waterless space environment, gas molecules or atoms will be preferentially adsorbed on the surface of the spacecraft, and chemical reactions will cause corrosion to the surface of the spacecraft. At the same time, when a spacecraft is in a space environment, it is in a radiation state. The energy of the radiated ultraviolet rays is relatively high (such as the energy of a single photon in ultraviolet rays with a wavelength of 300nm is 399kJ / mol), which will cause the chemical bonds in the material to break. The high-energy particles and cosmic rays in the radiation will trigger self-oxidation and degradation of polymers in the spacecraft, thereby affecting the service life of the spacecraft.

[0003] In space, the short-wave radiation from the sun will generate atomic oxygen, and the spacecraft will produce intense friction and collision with the atomic oxygen, causing high-temperature oxidation reactions in the materials. High-temperature oxidation reactions will cause the degradation of the electrical, optical and mechanical properties of the spacecraft materials, and ultimately produce an exploitation effect. In addition, in space, the temperature of the side of the spacecraft surface directly exposed to sunlight is as high as hundreds of degrees Celsius, and the temperature of the side not exposed to sunlight will drop to below -100°C. Extreme temperature conditions and large-scale hot and cold alternations will affect the stress of the material, causing the "outer coat" of the spacecraft to break, delaminate and become brittle.

[0004] In response to the above problems, the existing solution is mainly to coat the surface of the spacecraft. The coating materials mainly contain carbon, silicon, fluorine and nitrogen elements, forming a fluorine-silicon system, a fluorine-carbon system, a silicon-nitrogen system and a carbon-silicon system. In the fluorine-silicon system, the fluorine-silicon bond energy is high, and it has radiation resistance, corrosion resistance, oxidation stability, and thermal shock stability, but its adhesion is poor; in the fluorine-carbon system, the carbon-fluorine bond energy is relatively high, and it has radiation resistance, corrosion resistance, oxidation stability, and high adhesion, but its thermal shock stability is relatively poor; in the silicon-nitrogen system, it has high temperature resistance (resistant to 1800℃), oxidation stability, radiation resistance, and corrosion resistance, but its process is complicated, adhesion is poor, and the price is expensive; in the carbon-silicon system, it has high temperature resistance (resistant to 2500℃), oxidation stability, radiation resistance, and corrosion resistance, but its process is complicated, compatibility is poor, and the price is expensive.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a corrosion-resistant coating for vacuum working conditions and a preparation method and application thereof, which has the characteristics of high temperature resistance, oxidation stability, high adhesion, high corrosion resistance and excellent thermal shock stability, and is conducive to solving the problem of reduced service life of spacecraft in the space environment due to radiation, atomic oxygen and temperature.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] On the one hand, the present invention provides a corrosion-resistant coating for vacuum working conditions, which is formed by compounding a resin, a filler, an additive, and an organic solvent. The mass ratio of the resin, the filler, and the additive is (10-12): (3-5): (4-7), and the amount of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluoro-carbon-silicon polymer obtained by mixing 40-50 parts by weight of a fluorocarbon resin and 5-10 parts by weight of a silicone-modified acrylic resin.

[0009] Specifically, the modified fluorine-carbon-silicon polymer contains Si-CF bonds for resisting radiation and temperature difference. Preferably, the molecular weight of the modified fluorine-carbon-silicon polymer is 3000-4000.

[0010] Specifically, the filler includes the following components in parts by weight: 15 to 20 parts by weight of titanium dioxide and 0.5 to 1 part by weight of graphene.

[0011] Specifically, the auxiliary agent includes the following components by weight: 0.1-0.5 weight part of leveling agent, 0.8-1.5 weight part of clay powder, 0.5-1 weight part of defoaming agent, 1.5-2 weight part of anti-aging agent, 10-15 weight part of diluent, 0.2-0.5 weight part of light stabilizer, 5-10 weight part of matting powder, and 0.2-0.5 weight part of dispersant.

[0012] Specifically, the organic solvent is a mixture of one or more of anhydrous ethanol, xylene or n-butanol, preferably a mixture of xylene and n-butanol, with a mass ratio of 2:1.

[0013] On the other hand, the present invention also provides a method for preparing the corrosion-resistant coating for vacuum working conditions as described in part or in whole above, and the specific steps are as follows:

[0014] Step 1, mix and grind the resin, filler and dispersant in the additive until the mixed raw material particle size is ≤30 μm, and during the grinding process, control the grinding speed to 2000 r / min to 2500 r / min;

[0015] Step 2: Add the remaining additives to the mixed raw materials, and disperse them evenly using a dispersing device to obtain a corrosion-resistant coating for vacuum working conditions.

[0016] The dispersing equipment is a disperser with a dispersing speed of 800 r / min to 1200 r / min and a dispersing time of 40 min to 60 min.

[0017] In addition, the present invention also provides the use of the corrosion-resistant coating for vacuum conditions as described above in the surface coating of a spacecraft.

[0018] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0019] 1) A modified fluorine-carbon-silicon polymer is obtained by mixing 40 to 50 parts by weight of a fluorocarbon resin and 5 to 10 parts by weight of an organosilicon-modified acrylic resin. The polymer contains Si-CF bonds, has high bond energy, can resist radiation and temperature differences, and has strong reaction inertness to oxygen free radicals.

[0020] 2) The corrosion-resistant coating for vacuum conditions is applied to the coating on the surface of the spacecraft. In the process of preparing a fluoro-carbon-silicon composite polymer by mixing a fluorocarbon resin with a silicone-modified acrylic resin, the following advantages of the catalytic grafting technology are utilized: ① The phase separation problem of the fluorocarbon resin and the silicone-modified acrylic resin is eliminated through chemical bonding, which is beneficial to improving the mechanical properties of the blended material; ② The prepared modified fluoro-carbon-silicon polymer has a higher cross-linking density, which can make the coating have excellent bonding strength with the surface of the spacecraft, thereby resisting the environment of cold and hot shock.

[0021] 3) The filler proposed in the present invention achieves modification of the graphene surface by uniformly covering the graphene surface with a titanium dioxide particle layer (titanium dioxide) and forming a transition layer between the vacuum environment and the graphene; during the entire coating process, as the layer thickness continues to increase, the modified graphene surface forms a stacked structure, and the multilayer structure together forms a dense protective layer, which can not only enhance the corrosion resistance of the coating, but also improve the mechanical properties of the coating such as mechanical strength, hardness, wear resistance and impact resistance.

[0022] Based on the improvements in the above three aspects, the corrosion-resistant coating for vacuum working conditions provided by the present invention has the advantages of high temperature resistance, oxidation stability, high adhesion, high corrosion resistance and excellent thermal shock stability, and can solve the problem of reduced service life of spacecraft caused by radiation, atomic oxygen and temperature in the space environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 The present invention provides a flow chart of a method for preparing a corrosion-resistant coating for vacuum working conditions. DETAILED DESCRIPTION

[0026] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The weight portions of the coatings in Examples 1 to 3 are shown in Table 1 below, and the amount of the organic solvent is determined according to the target viscosity (viscosity) of the coating to be compounded.

[0028] Table 1 Weight parts of raw materials used in coatings in Examples 1 to 3

[0029]

[0030]

[0031] Example 1

[0032] See also Figure 1 As shown, this embodiment provides a corrosion-resistant coating for vacuum working conditions, which is formed by compounding resin, filler, additives, and organic solvents. The mass ratio of the resin, filler, and additives is close to 10:3:4, and the amount of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluoro-carbon-silicon polymer obtained by mixing 45 parts by weight of fluorocarbon resin and 5 parts by weight of silicone-modified acrylic resin; wherein the acrylic resin is used to improve the flexibility of the coating.

[0033] The modified fluorine-carbon-silicon polymer contains Si-CF bonds for resisting radiation and temperature difference. Preferably, the molecular weight of the modified fluorine-carbon-silicon polymer is 3,000.

[0034] Furthermore, the filler comprises the following components in parts by weight: 15 parts by weight of titanium dioxide and 0.5 parts by weight of graphene; wherein the titanium dioxide is used to improve the hiding power of the coating.

[0035] Furthermore, the auxiliary agent includes the following components by weight: 0.1 weight part of leveling agent, 0.8 weight part of clay powder, 0.5 weight part of defoaming agent, 1.5 weight part of anti-aging agent, 10 weight parts of diluent, 0.2 weight part of light stabilizer, 5 weight part of matting powder, and 0.2 weight part of dispersant.

[0036] Furthermore, the organic solvent is 8.4 parts by weight of anhydrous ethanol.

[0037] In addition, this embodiment also provides a method for preparing a corrosion-resistant coating for vacuum working conditions, and the specific steps are as follows:

[0038] Step 1, mix and grind the resin, filler and dispersant in the additive until the particle size of the mixed raw materials is ≤30 μm, and control the grinding speed to 2000 r / min;

[0039] Step 2: Add the remaining additives to the mixed raw materials, and disperse them evenly using a disperser to obtain a corrosion-resistant coating for vacuum working conditions. The dispersion speed is 800 r / min and the dispersion time is 60 min.

[0040] Example 2

[0041] The present embodiment provides a corrosion-resistant coating for vacuum working conditions, which is formed by compounding a resin, a filler, an additive, and an organic solvent. The mass ratio of the resin, the filler, and the additive is close to 10:4:5, and the amount of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluoro-carbon-silicon polymer obtained by mixing 40 parts by weight of a fluorocarbon resin and 10 parts by weight of an organosilicon-modified acrylic resin; wherein the acrylic resin is used to improve the flexibility of the coating.

[0042] The modified fluorine-carbon-silicon polymer contains Si-CF bonds for resisting radiation and temperature difference. Preferably, the molecular weight of the modified fluorine-carbon-silicon polymer is 3500.

[0043] Furthermore, the filler comprises the following components by weight: 18 parts by weight of titanium dioxide and 0.8 parts by weight of graphene; wherein the titanium dioxide is used to improve the hiding power of the coating.

[0044] Furthermore, the auxiliary agent includes the following components by weight: 0.3 weight part of leveling agent, 1 weight part of clay powder, 0.7 weight part of defoaming agent, 1.7 weight part of anti-aging agent, 13 weight parts of diluent, 0.4 weight part of light stabilizer, 7 weight parts of matting powder, and 0.3 weight part of dispersant.

[0045] Furthermore, the organic solvent is a mixed solution of 7.4 parts by weight of xylene and 3.7 parts by weight of n-butanol, and the mass ratio of xylene to n-butanol is 2:1.

[0046] In addition, this embodiment also provides a method for preparing a corrosion-resistant coating for vacuum working conditions, and the specific steps are as follows:

[0047] Step 1, mix and grind the resin, filler and dispersant in the additive until the particle size of the mixed raw materials is ≤30 μm, and control the grinding speed to 2200 r / min;

[0048] Step 2: Add the remaining additives to the mixed raw materials, and disperse them evenly using a disperser to obtain a corrosion-resistant coating for vacuum working conditions. The dispersion speed is 1000 r / min and the dispersion time is 50 min.

[0049] Example 3

[0050] The present embodiment provides a corrosion-resistant coating for vacuum working conditions, which is formed by compounding a resin, a filler, an additive, and an organic solvent. The mass ratio of the resin, the filler, and the additive is close to 12:4:6, and the amount of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluoro-carbon-silicon polymer obtained by mixing 50 parts by weight of a fluorocarbon resin and 10 parts by weight of an organosilicon-modified acrylic resin; wherein the acrylic resin is used to improve the flexibility of the coating.

[0051] The modified fluorine-carbon-silicon polymer contains Si-CF bonds for resisting radiation and temperature difference. Preferably, the molecular weight of the modified fluorine-carbon-silicon polymer is 4,000.

[0052] Furthermore, the filler comprises the following components by weight: 20 parts by weight of titanium dioxide and 1 part by weight of graphene; wherein the titanium dioxide is used to improve the hiding power of the coating.

[0053] Furthermore, the auxiliary agent includes the following components in parts by weight: 0.5 parts by weight of leveling agent, 1.5 parts by weight of clay powder, 1 part by weight of defoaming agent, 2 parts by weight of antioxidant, 15 parts by weight of diluent, 0.5 parts by weight of light stabilizer, 10 parts by weight of matting powder, and 0.5 parts by weight of dispersant.

[0054] Furthermore, the organic solvent is 16.8 parts by weight of n-butanol.

[0055] In addition, this embodiment also provides a method for preparing a corrosion-resistant coating for vacuum working conditions, and the specific steps are as follows:

[0056] Step 1, mix and grind the resin, filler and dispersant in the additive until the particle size of the mixed raw materials is ≤30 μm, and control the grinding speed to 2500 r / min;

[0057] Step 2: Add the remaining additives to the mixed raw materials, and disperse them evenly using a disperser to obtain a corrosion-resistant coating for vacuum working conditions. The dispersion speed is 1200 r / min and the dispersion time is 40 min.

[0058] The corrosion-resistant coating for vacuum working conditions prepared in the above Examples 1 to 3 is used as a coating on the surface of a spacecraft, and the coating has excellent bonding strength with the surface of the spacecraft. At the same time, the coating is tested as follows:

[0059] 1) The solid content of the coating is tested according to GB / T 1725, and the solid content of the coating is not less than 55%.

[0060] 2) The viscosity of the coating is tested according to GB / T 9629, and the test shows that the viscosity of the coating is not less than 60KU. The KU value is obtained by testing with a four-cup viscometer to reflect the difficulty of stirring the coating.

[0061] 3) The surface drying time, actual drying time and baking time are tested in accordance with GB / T 1728. The surface drying time of the coating prepared by the coating is not more than 1 hour at room temperature, and the actual drying time is not more than 24 hours; it is dried in an environment of 50℃±1℃, and the drying time is not more than 6 hours.

[0062] 4) The flexibility is tested according to GB / T 1731. The flexibility of the coating prepared by using the coating is tested to be no more than 2 mm, which means that the coating can bend or stretch to a maximum of 2 mm without breaking or falling off when subjected to external force.

[0063] 5) The impact resistance of the coating prepared by the coating is tested according to GB / T 1732, and the test shows that the impact resistance of the coating prepared by the coating is 50cm, which means that when the coating is subjected to the impact test, the maximum impact force that it can withstand is a 1kg hammer falling freely from a height of 50cm without causing damage to the coating.

[0064] 6) According to GB / T 9286, the adhesion of the coating prepared by the coating was tested by the cross-cut method, and the adhesion of the coating was found to be level 1.

[0065] 7) The hardness of the prepared coating was measured according to GB / T 6739, and the pencil hardness of the coating was not less than 2H. The appearance, impact resistance and adhesion of the coating were tested after the heat resistance test according to GB / T 1735, GB / T 1732 and GB / T 9286. The heat resistance test refers to the performance measurement of the coating after heating it in an environment of 200℃±5℃ for 4h. The coating was not discolored, the impact test was 50cm, and the adhesion was tested by the cross-hatch method and was level 1.

[0066] 8) The prepared coating was tested for low temperature resistance according to GJB 150.4A. The low temperature resistance test refers to testing whether the coating cracks or does not peel off in an environment of -55°C±2°C for 4 hours. After the low temperature resistance test, the coating did not crack or peel off.

[0067] 9) According to GB / T 1865 and GB / T 1766, the artificial accelerated aging resistance (3000h) test was carried out, and the test results showed that the powdering was level 0 and the cracking was level 0.

[0068] 10) The fungus resistance of the coating was tested according to GJB 150.10A, and the fungus resistance was finally measured to be level 0.

[0069] In summary, the corrosion-resistant coating for vacuum working conditions provided by the present invention can resist radiation and temperature differences due to the high bond energy of Si-CF bonds in the process of preparing modified fluorocarbon-carbon-silicon composite high molecular polymers by mixing fluorocarbon resins and silicone-modified acrylic resins; and the modified fluorocarbon-carbon-silicon composite high molecular polymers have a high crosslinking density, which can make the coating have excellent bonding with the surface of the spacecraft, thereby resisting the environment of cold and hot shocks; in addition, a transition layer (titanium dioxide particle layer, the thickness of which is related to the particle size of the titanium dioxide particles) is formed between the vacuum environment and the graphene, and during the entire coating process, as the layer thickness continues to increase, a stacked structure is formed on the surface of the modified graphene, and the multi-layer structure together forms a dense protective layer, which can not only enhance the corrosion resistance of the coating, but also improve the mechanical properties of the coating such as mechanical strength, hardness, wear resistance and impact resistance, effectively solving the problem of reduced service life of spacecraft in the space environment due to radiation, atomic oxygen and temperature.

[0070] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0071] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A corrosion-resistant coating for vacuum working conditions, characterized in that: The invention is formed by compounding resin, filler, auxiliary agent and organic solvent, wherein the mass ratio of the resin, filler and auxiliary agent is (10-12):(3-5):(4-7), and the amount of the organic solvent is determined according to the target viscosity of the coating to be compounded; the resin is a modified fluoro-carbon-silicon high molecular polymer obtained by mixing 40-50 parts by weight of fluorocarbon resin and 5-10 parts by weight of silicone-modified acrylic resin.

2. The corrosion-resistant coating for vacuum working conditions according to claim 1, characterized in that: The modified fluorine-carbon-silicon macromolecular polymer contains Si-CF bonds for resisting radiation and temperature difference.

3. The corrosion-resistant coating for vacuum working conditions according to claim 2, characterized in that: The molecular weight of the modified fluorine-carbon-silicon high molecular polymer is 3000-4000.

4. The corrosion-resistant coating for vacuum working conditions according to claim 1, characterized in that: The filler comprises the following components in parts by weight: 15 to 20 parts by weight of titanium dioxide and 0.5 to 1 part by weight of graphene.

5. The corrosion-resistant coating for vacuum working conditions according to claim 1, characterized in that: The auxiliary agent comprises the following components in parts by weight: 0.1-0.5 parts by weight of leveling agent, 0.8-1.5 parts by weight of clay powder, 0.5-1 parts by weight of defoaming agent, 1.5-2 parts by weight of anti-aging agent, 10-15 parts by weight of diluent, 0.2-0.5 parts by weight of light stabilizer, 5-10 parts by weight of matting powder and 0.2-0.5 parts by weight of dispersant.

6. The corrosion-resistant coating for vacuum working conditions according to claim 1, characterized in that: The organic solvent is a mixture of one or more of anhydrous ethanol, xylene or n-butanol.

7. A method for preparing a corrosion-resistant coating for vacuum working conditions as claimed in any one of claims 1 to 6, characterized in that: The specific steps are as follows: Step 1, mixing and grinding the resin, filler and dispersant in the additive until the particle size of the mixed raw material is ≤30 μm; Step 2: Add the remaining additives to the mixed raw materials, and disperse them evenly using a dispersing device to obtain a corrosion-resistant coating for vacuum working conditions.

8. The method for preparing the corrosion-resistant coating for vacuum working conditions according to claim 7, characterized in that: During the mixing and grinding process, the grinding speed is controlled to be 2000r / min~2500r / min.

9. The method for preparing the corrosion-resistant coating for vacuum working conditions according to claim 7, characterized in that: The dispersing equipment adopts a disperser with a dispersing speed of 800r / min to 1200r / min and a dispersing time of 40min to 60min.

10. Use of the corrosion-resistant coating for vacuum conditions according to any one of claims 1 to 6 or the corrosion-resistant coating for vacuum conditions prepared by the preparation method according to any one of claims 7 to 9 in spacecraft surface coating.

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