A method of controlling the temperature of a substrate based on cold spraying

Abstract

The application provides a kind of substrate temperature control method based on cold spraying, comprising the following steps: immerse the repaired part into film forming paint, the film forming paint is film forming, the repaired part is repaired using cold spraying technology, and the repair is completed after the film is torn off after spraying is finished. Wherein, the film forming paint is prepared by mixing component A, component B and curing agent according to the mass ratio of 60:40:0.8-1.5; the component A is mainly composed of fluororesin, fluorinated alkyl silane, fluorine-containing acrylate and the like; the component B is mainly composed of metal fluoride. The film forming paint prepared by the application has good film forming performance, good cohesion, good compatibility, low adhesion (50g-300g / 25mm), can be easily peeled off after spraying is finished while having certain adhesion; on the one hand, it can protect the substrate, on the other hand, it can convert the heat energy emitted by the substrate into light energy, realize the cooling effect, so as to obtain a coating with better spraying quality.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cold spraying repair, and particularly relates to a substrate temperature control method based on cold spraying. BACKGROUND

[0002] Cold spraying repair technology is a technology that uses preheated high-speed gas to accelerate and heat raw material powder, and then impacts the substrate in a solid state to realize bonding through severe plastic deformation of the substrate and particles. As a low-temperature processing technology, cold spraying has less thermal influence on raw materials, and the formed coating has low porosity, high bonding strength and is in a compressive stress state, and has good mechanical, thermal, electrical and other properties. Cold spraying repair technology has wide application in the fields of aviation, aerospace, machinery and the like, such as airplane landing gear, crystallizer copper plate, cavitation pit of force pump volute, titanium alloy thin-walled parts and the like.

[0003] In the existing cold spraying repair technology, the critical velocity of particles is a key parameter for forming a coating by spraying, and is highly concerned. In the calculation model of the critical velocity, the particle temperature has the most significant influence on the critical velocity. High-temperature gas softens the sprayed particles, enhances the plastic deformation ability of the particles, and makes the adiabatic shear instability behavior more likely to occur, so that the critical velocity required for the particles to deposit is smaller. The existing cold spraying equipment can heat the gas temperature to 400-550℃, and the calculation of the related theoretical model shows that the critical velocity of the particles to deposit and form a coating will decrease by 40m / s-50m / s per 100℃ increase in the particle temperature, indicating that the temperature parameter plays an important role in the cold spraying process.

[0004] The current research on the temperature parameter mainly focuses on the temperature of the sprayed particles, but in the actual spraying process, the surface temperature of the sprayed substrate also plays a crucial role. In the process of particle deposition to form a coating, the particles and the substrate undergo plastic deformation at the same time, and at this time, the substrate temperature also has an influence on the deposition behavior of the particles. The substrate temperature has an important influence on the macroscopic morphology, interface morphology, organizational characteristics, deposition thickness, microhardness, particle deposition efficiency and other properties of the cold spraying repair coating. For example, cold sprayed copper particles are deposited on the surface of the substrate at high speed, and if the heat dissipation of the substrate surface is not timely during the spraying process, the copper coating will be oxidized and discolored, affecting the performance of the coating. Cold sprayed stainless steel particles are deposited on the surface of the substrate at different heating temperatures, and the deposition efficiency of the particles increases with the increase of the substrate temperature. Within the critical oxidation film thickness range (there is a critical thickness of 3-4μm of the oxidation film on the surface of the heated substrate), the high-speed sprayed particles can completely break the oxidation film and expose the fresh substrate surface, so that the particles are deposited on the fresh substrate surface to prepare a dense cold sprayed coating.

[0005] At present, there is no effective temperature control method for the cold spraying substrate, and the substrate is involved in airflow, rotation and the like in the cold spraying repair process, so the general cooling method is not applicable. In addition, the substrate for cold spraying repair is various and complex in structure, and the substrate temperature is not easy to control when repairing a certain part, and the existing water cooling and air cooling method is not effective and is not easy to realize. SUMMARY

[0006] In view of this, the application provides a substrate temperature control method based on cold spraying.

[0007] To achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0008] A substrate temperature control method based on cold spraying, comprising the following steps:

[0009] The repaired part is immersed in the film-forming coating, the film-forming coating is formed, the cold spraying technology is used to repair the repaired part, and the repair is completed after the film is torn off after spraying is completed;

[0010] The film-forming coating is prepared by mixing component A, component B and curing agent in a mass ratio of 60:40:0.8-1.5.

[0011] The component A is composed of the following components in parts by weight: fluororesin 40-81 parts, ultra-fine powder 1-2 parts, fluoroalkylsilane 5-20 parts, fluorine-containing acrylic ester monomer 10-20 parts, leveling agent 1-5 parts and dispersing agent 1-5 parts.

[0012] The component B is composed of ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 in a molar ratio of (50-55):(18-20):(2-4):(2-4):(18-20):1.

[0013] Further, before the repaired part is immersed in the film-forming coating, the surface of the substrate of the repaired part is sandblasted with ferrosilicate particles, and then the surface of the substrate of the repaired part is cleaned with acetone and naturally dried.

[0014] In some embodiments, preferably, the film-forming coating is prepared by mixing component A, component B and curing agent in a mass ratio of 60:40:1.

[0015] The component A is composed of the following components in parts by weight: fluororesin 60 parts, ultra-fine powder 2 parts, fluoroalkylsilane 12 parts, fluorine-containing acrylic ester monomer 15 parts, leveling agent 3 parts and dispersing agent 3 parts.

[0016] The component B is composed of ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 in a molar ratio of 54:19:3:3:20:1.

[0017] Further, the curing agent is diisocyanate;

[0018] The fluororesin is fluorovinylethylene vinyl ether resin;

[0019] The fluorinated alkyl silane is at least one of trimethyl pentaf luorophenyl silane and trifluoromethyl trimethyl silane;

[0020] The fluorine-containing acrylic ester monomer includes but is not limited to at least one of monomethyl 2,2,2-trif luoroethyl acrylate and monomethyl 1,1,2,2-tetrafluorodecyl acrylate;

[0021] The superfine powder includes but is not limited to at least one of quartz powder and silicon micro powder;

[0022] The leveling agent is polyacrylic acid;

[0023] The dispersing agent is polyacrylamide.

[0024] Further, the film-forming coating preparation method includes the following steps:

[0025] Take the superfine powder, fluorinated alkyl silane, leveling agent, and dispersing agent to mix and perform ultrasonic treatment, then add the fluororesin and fluorine-containing acrylic ester monomer to perform ultrasonic treatment, to obtain a mixed slurry;

[0026] Take ZrF4, BaF2, LaF3, AIF3, NaF, and ErF3 to mix uniformly, perform calcination, water washing, ball milling, washing, filtration, drying, and sieving, to obtain a mixed powder;

[0027] Take the mixed slurry, mixed powder, and curing agent to mix, stir, and stand, to obtain the film-forming coating.

[0028] Further, the particle size of the mixed powder is 15-25 μm.

[0029] Further, the to-be-repaired member includes but is not limited to an aluminum alloy substrate, a magnesium alloy substrate, a titanium alloy substrate, an aviation part, an automobile part, and a steel member.

[0030] Further, the parameters of the cold spraying repair are that the working gas is at least one of air, nitrogen, and helium, the spraying pressure is 1-9 Mpa, the spraying temperature is 100-1100 °C, the gas speed is 150-1100 m / s, the spraying distance is 5-120 mm, and the spraying angle is 45-90°.

[0031] Compared with the prior art, the film-forming coating prepared by the application has good film-forming performance, good cohesion, good compatibility, low viscosity (50g-300g / 25mm), certain adhesion, and can be easily peeled off after spraying is finished; on one hand, the film-forming coating can protect the substrate, and on the other hand, the film-forming coating can convert the heat energy emitted by the substrate into light energy to achieve the effect of cooling, so that a coating with better spraying quality is obtained. DETAILED DESCRIPTION

[0032] The application will be further described in detail below with reference to specific examples, so that those skilled in the art can more clearly understand the application.

[0033] The ultrafine powder, the fluoroalkylsilane (FAS), the leveling agent and the dispersant are uniformly mixed, and then are dispersed and treated by using an ultrasonic cell pulverizer; then the fluororesin and the fluorine-containing acrylic ester monomer are added and dispersed and treated by using the ultrasonic cell pulverizer to obtain a mixed slurry.

[0034] Zirconium tetrafluoride, barium fluoride, lanthanum fluoride, aluminum fluoride and sodium fluoride are uniformly mixed according to a molar ratio of (50-55):(18-20):(2-4):(2-4):(18-20):1, and then are calcined; after being cooled to room temperature, the mixture is washed by water, ball milled, and then is sequentially washed by hydrochloric acid and ammonia solution, filtered, dried and sieved to obtain a mixed powder.

[0035] The mixed slurry, the mixed powder and the curing agent are mixed according to a mass ratio of 60:40:0.8-1.5, and then are stirred and left to obtain the film-forming coating.

[0036] The repaired part is immersed in the film-forming coating, the film-forming coating is formed, the repaired part is repaired by using cold spraying technology, and the film is torn off after spraying is finished to complete the repair.

[0037] The fluororesin in the film-forming coating component A prepared by the application has the properties of low surface energy and thermal stability; and according to the bionics principle of "lotus self-cleaning effect", the ultrafine powder is used to construct a rough structure on the surface of the coating to improve the hydrophobicity of the coating;

[0038] The FAS is added in the coating, and the -CF3 groups of the FAS migrate to the surface to make the surface of the coating rich in -CF3 groups to further reduce the surface energy;

[0039] The fluorine-containing acrylic ester monomer can be homopolymerized or copolymerized by a free radical polymerization mechanism, and can be copolymerized with many similar monomers without fluorine to produce different materials with certain fluorine content; in order to obtain higher chemical or light stability, film-forming performance and water repellency, the fluorine-containing acrylic ester monomer can also provide certain adhesion;

[0040] The leveling agent can promote the coating to form a flat, smooth and uniform coating film during the drying process, effectively reduce the surface tension of the finishing liquid, improve the leveling and uniformity, improve the permeability of the finishing liquid, reduce the possibility of producing spots and marks during brushing, increase the coverage, and make the film uniform and natural.

[0041] The prepared film-forming coating component B utilizes the anti-Stokes effect, and the scattered fluorescent photon wavelength is shorter than the incident photon wavelength. Therefore, the scattered fluorescent photon energy is higher than the incident photon energy, and the process can be simply understood as follows: the low-energy laser photon is used to excite the luminescent medium, the luminescent medium scatters high-energy photons, the original energy in the luminescent medium is taken out of the medium to cool; and the heavy metal fluoride can effectively inhibit the non-radiative transition due to its low phonon energy, so that effective and pure fluorescent refrigeration is obtained.

[0042] The other raw materials or structures not specifically described in the present application already exist in the prior art and can be directly purchased from the market.

[0043] Example 1

[0044] The embodiment provides a substrate temperature control method based on cold spraying, a magnesium alloy is used as a substrate of a repaired part, and aluminum alloy powder is sprayed on the substrate to repair the part, and the specific operation is as follows:

[0045] The ultra-fine powder 2 parts, trimethyl five-fluorophenyl silane 12 parts, polyacrylic acid 3 parts and polyacrylamide 3 parts are uniformly mixed, and then are dispersed and treated by using an ultrasonic cell crusher for 30 minutes; then, fluorine ethylene vinyl ether resin 60 parts and methyl methacrylate 2,2,2-trifluoroethyl ester 15 parts are added, and are dispersed and treated by using the ultrasonic cell crusher for 30 minutes, to obtain a mixed slurry.

[0046] ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 are weighed according to a molar ratio of 54:19:3:3:20:1, are uniformly mixed, and are placed in an alumina dry pan; the alumina dry pan is moved into a muffle furnace and is calcined at 900 DEG C for 5 minutes; after being cooled to room temperature, the mixture is washed with water, ball milled, and then is sequentially washed with hydrochloric acid and ammonia solution, filtered, dried and sieved, to obtain a mixed powder with a particle size of 20 microns.

[0047] The mixed slurry, the mixed powder and the curing agent are taken according to a mass ratio of 60:40:1, are stirred at a speed of 200 r / min for 20 minutes, and then are left to stand for 20 minutes, to obtain the film-forming coating.

[0048] Before the repaired part is immersed into the film forming coating, the surface of the base of the repaired part is sandblasted with ferrosilicate particles, then the surface of the base of the repaired part is cleaned with acetone, and naturally dried, and then the repaired part is immersed into the film forming coating, and after the film forming coating is formed, the repaired part is repaired by cold spraying technology, and after the spraying is completed, the film is torn off to complete the repair.

[0049] The parameters of the cold spraying repair are as follows: the working gas of the cold spraying repair is one or more of air, nitrogen or helium; the spraying pressure of the cold spraying repair is 5 Mpa; the spraying temperature of the cold spraying repair is 800 DEG C; the gas speed of the cold spraying repair is 800 m / s; the spraying distance of the cold spraying repair is 50 mm; and the spraying angle of the cold spraying repair is 60 DEG.

[0050] Example 2

[0051] The embodiment provides a base temperature control method based on cold spraying, the repair steps and process of which are the same as those of example 1, and the difference lies in the preparation of the film forming coating, which is prepared as follows:

[0052] The ultrafine powder 1.5 parts, trifluoromethyltrimethylsilane 8 parts, polyacrylic acid 5 parts and polyacrylamide 2 parts are uniformly mixed, and then dispersed and treated by using an ultrasonic cell crusher for 30 minutes, and then fluorovinyl vinyl ether resin 45 parts and 1,1,2,2-tetrafluorodecyl methacrylate 10 parts are added, and then dispersed and treated by using an ultrasonic cell crusher for 30 minutes to obtain a mixed slurry.

[0053] ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 are weighed according to a molar ratio of 50:18:3:3:18:1, uniformly mixed and placed in an alumina pan, the alumina pan is moved into a muffle furnace and calcined at 900 DEG C for 5 minutes, and then cooled to room temperature, washed with water, ball milled, and then washed with hydrochloric acid and ammonia solution, filtered, dried and sieved to obtain a mixed powder with a particle size of 15 microns.

[0054] The mixed slurry, the mixed powder and the curing agent are mixed according to a mass ratio of 60:40:0.8, stirred at a speed of 200 r / min for 20 minutes, and then left to stand for 20 minutes to obtain the film forming coating.

[0055] Example 3

[0056] The embodiment provides a base temperature control method based on cold spraying, the repair steps and process of which are the same as those of example 1, and the difference lies in the preparation of the film forming coating, which is prepared as follows:

[0057] The ultrafine powder 1 part, trimethyl five fluorophenyl silane 20 parts, polyacrylic acid 1 part, polyacrylamide 5 parts are mixed uniformly, and are dispersed and treated by using an ultrasonic cell pulverizer for 30 minutes. Then, fluorovinyl vinyl ether resin 80 parts, methyl methacrylate 2,2,2-trifluoroethyl ester 10 parts, and methyl methacrylate 1,1,2,2-tetrafluorodecyl ester 10 parts are added, and are dispersed and treated by using an ultrasonic cell pulverizer for 30 minutes, to obtain a mixed slurry.

[0058] ZrF4, BaF2, LaF3, AIF3, NaF, and ErF3 are weighed according to a molar ratio of 55:20:3:3:20:1, are mixed uniformly, and are placed in an alumina crucible. The alumina crucible is moved into a muffle furnace and is calcined at 900°C for 5 minutes. After cooling to room temperature, the mixture is washed with water, ball milled, and then is washed with hydrochloric acid and ammonia solution, filtered, dried, and sieved, to obtain a mixed powder with a particle size of 25 μm.

[0059] The mixed slurry, the mixed powder, and the curing agent are mixed according to a mass ratio of 60:40:1.5, are stirred at a speed of 200 r / min for 20 minutes, and are then left to stand for 20 minutes, to obtain a film-forming coating.

[0060] Comparative Example 1

[0061] This comparative example provides a substrate temperature control method based on cold spraying, which has basically the same raw materials and steps as Example 1, except that an equal amount of phenolic resin is used to replace the fluorovinyl vinyl ether resin, and the rest remains unchanged.

[0062] Comparative Example 2

[0063] This comparative example provides a substrate temperature control method based on cold spraying, which has basically the same raw materials and steps as Example 1, except that the amount of fluorovinyl vinyl ether resin is changed from 60 parts to 30 parts, and the rest remains unchanged.

[0064] Comparative Example 3

[0065] This comparative example provides a substrate temperature control method based on cold spraying, which has basically the same raw materials and steps as Example 1, except that trimethyl five fluorophenyl silane is removed, and the rest remains unchanged.

[0066] Comparative Example 4

[0067] This comparative example provides a substrate temperature control method based on cold spraying, which has basically the same raw materials and steps as Example 1, except that the molar ratio of ZrF4, BaF2, LaF3, AIF3, NaF, and ErF3 is changed to 1:1:1:1:1, and the rest remains unchanged.

[0068] The cold spraying repair effects of examples 1-3 and comparative examples 1-4 are detected, and the results are shown in Table 1 below; wherein the control group is directly sprayed without applying any coating.

[0069] Table 1 Influence of different film forming materials on spraying effect

[0070]

[0071]

[0072] Wherein: the porosity index test method is according to GB / T 17721-1999 "Metallic Coating Porosity Test Iron Reagent Test"; the impact resistance index test method is according to GB / T 1732-2020 "Paint Film Impact Resistance Test Method"; the neutral salt spray resistance performance index test method is according to GB / T 1771-2007 "Determination of Resistance to Neutral Salt Spray of Paint and Varnish"; the artificial accelerated aging index test method is according to GB T 1865-2009 "Artificial Weathering and Artificial Radiation Exposure of Paint and Varnish Filtered Xenon Arc Radiation"; the deposition efficiency test method is according to ISO 8130-10-2021 "Powder Coatings Part 10: Determination of Deposition Efficiency"; the substrate temperature is detected by infrared temperature measurement.

[0073] From the above table results, it can be seen that the film forming coating prepared by the present application has low porosity, strong impact resistance, strong neutral salt spray resistance of the workpiece after spraying, and strong anti-aging ability when cold spraying. Compared with the comparative group and the control group, there is obvious improvement. And the film forming coating prepared by the present application is suitable for workpieces with complex structure, and can also play a good technical effect on parts that are not suitable for cooling.

[0074] The above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling the temperature of a substrate based on cold spraying, characterized in that, The method comprises the following steps: The component to be repaired is immersed in the film-forming coating, the film-forming coating is formed, the component to be repaired is repaired by using the cold spraying technology, and the repair is completed by tearing off the film after the spraying is completed; The film-forming coating is prepared by mixing component A, component B and a curing agent according to a mass ratio of 60:40:1; The component A is composed of the following components in parts by weight: fluororesin 60 parts, ultra-fine powder 2 parts, fluoroalkyl silane 12 parts, fluorine-containing acrylic ester monomer 15 parts, leveling agent 3 parts and dispersing agent 3 parts; The component B is composed of ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 according to a molar ratio of (50-55):(18-20):(2-4):(2-4):(18-20):

1.

2. The method of claim 1, wherein, Before the component to be repaired is immersed in the film-forming coating, the surface of the base of the component to be repaired is sandblasted by using ferrosilicate particles, and then the surface of the base of the component to be repaired is cleaned with acetone and naturally dried.

3. The method of claim 1, wherein, The film-forming coating is prepared by mixing component A, component B and a curing agent according to a mass ratio of 60:40:1; The component A is composed of the following components in parts by weight: fluororesin 60 parts, ultra-fine powder 2 parts, fluoroalkyl silane 12 parts, fluorine-containing acrylic ester monomer 15 parts, leveling agent 3 parts and dispersing agent 3 parts; The component B is composed of ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 according to a molar ratio of 54:19:3:3:20:

1.

4. The method according to any one of claims 1 to 3, characterized in that, The curing agent is diisocyanate; The fluororesin is fluorovinyl vinyl ether resin; The fluoroalkyl silane is at least one of trimethyl pentaf luorophenyl silane and trifluoromethyl trimethyl silane; The fluorine-containing acrylic ester monomer includes at least one of monomer 2,2,2-trif luoroethyl methacrylate and monomer 1,1,2,2-tetrafluorodecyl methacrylate; The ultra-fine powder includes at least one of quartz powder and silicon powder; The leveling agent is polyacrylic acid; The dispersing agent is polyacrylamide.

5. The method of claim 4, wherein, The film-forming coating is prepared by mixing component A, component B and a curing agent according to a mass ratio of 60:40:1; The ultra-fine powder, fluoroalkyl silane, leveling agent and dispersing agent are mixed and ultrasonically treated, then the fluororesin and fluorine-containing acrylic ester monomer are added and ultrasonically treated to obtain a mixed slurry; ZrF4, BaF2, LaF3, AIF3, NaF and ErF3 are uniformly mixed, calcined, washed with water, ball milled, washed, filtered, dried and sieved to obtain a mixed powder; The mixed slurry, mixed powder and curing agent are mixed, stirred and left to stand to obtain the film-forming coating.

6. The method of claim 5, wherein, The particle size of the mixed powder is 15-25 µm.

7. The method of claim 1, wherein, The component to be repaired includes an aluminum alloy base, a magnesium alloy base, a titanium alloy base and a steel component.

8. The method of claim 1, wherein, The component to be repaired includes an aviation part and an automobile part.

9. The method of claim 1, wherein, The parameters of the cold spraying repair include that the working gas is at least one of air, nitrogen and helium, the spraying pressure is 1-9 MPa, the spraying temperature is 100-1100 ℃, the gas speed is 150-1100 m / s, the spraying distance is 5-120 mm and the spraying angle is 45-90°.

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