Ternary hybrid hole sealing agent as well as preparation method and application thereof

Abstract

The invention belongs to the field of hole sealing agents for high-entropy alloy coatings, and relates to a ternary hybrid hole sealing agent as well as a preparation method and application thereof. Comprising the following steps: mixing water-based organic silicon modified acrylic resin with deionized water, and homogenizing to obtain a solution A; dissolving sodium molybdate and thiourea in deionized water, and stirring to form a clear solution B; sodium molybdate and thiourea form a molybdenum disulfide precursor; adding a surface modifier into deionized water, and uniformly mixing to obtain a solution C; mixing the solution A and the solution C, continuing to stir, introducing a graphene oxide (GO) dispersion liquid by adopting a dropwise adding method, and ensuring that graphene oxide is uniformly dispersed to obtain a GO modified A / C mixed system; and slowly adding the solution B into the GO-modified A / C mixed system, and continuously stirring to obtain the uniform and stable ternary hybrid hole sealing agent. According to the invention, pores in the coating are effectively filled, the barrier property to corrosive media is improved, and the service durability of the coating is improved.

Description

Technical Field

[0001] The present invention belongs to the field of sealants for high-entropy alloy coatings, and relates to a ternary hybrid sealant, its preparation method and uses. Background Art

[0002] Among various research directions in the field of surface engineering, the plasma spraying technology has shown significant advantages in preparing high-entropy alloy coatings and has become an important research direction in the field of surface engineering. Compared with other preparation processes, this technology has excellent process adaptability. Its high deposition rate not only meets the requirements of industrial production for efficiency but also enables the rapid preparation of thick coatings. At the same time, it has excellent compatibility with multi-component alloy systems and can achieve diverse coating properties. By optimizing process parameters such as plasma gas composition and powder particle size distribution, the residual stress and phase composition of the coating can be effectively regulated to meet the specific requirements of different service environments. In addition, its equipment cost is relatively low and it is easy to automate, which makes the plasma spraying technology have broad application prospects in the field of high-entropy alloy coating preparation.

[0003] However, due to the rapid cooling and solidification of molten particles during plasma spraying and the layered stacking, the coating often has defects such as high porosity, weak interlayer bonding force and fine cracks. From the coating formation process, the spraying particles go through stages such as flying and accelerating, impacting the substrate, rapid cooling and solidification. During this period, the high-temperature particles are oxidized by the ambient gas, forming oxide inclusions, which affect the microstructure and macroscopic properties of the coating. In addition, when the flattened particles are stacked layer by layer, the bonding strength is insufficient, resulting in interfacial pores at the grain boundaries. And when the shrinkage stress generated by rapid cooling exceeds the strength limit of the coating material, microcracks and pores will also be induced. These pores and cracks are prone to cause the penetration of corrosive media during use, leading to local failure of the substrate metal. At the same time, under high-temperature cycling, loading and wear, stress concentration at the pore edges will induce coating peeling, reducing the protective performance. In order to improve the service life of the coating and reduce the porosity of the coating, certain post-treatment is required to block the connection channels between the metal substrate and the corrosive medium.

[0004] For the need to seal the pores of plasma-sprayed coatings, traditional post-treatment uses sealants, and most of them choose epoxy resins for sealing. However, such materials show certain limitations in practical applications. Epoxy resins have good fluidity, sealing performance and relatively good adhesion, but they will undergo thermal decomposition and carbonization in high-temperature environments, the sealing performance is affected and decreased, and even phenomena such as peeling occur. Organic sealants have similar commonalities. Inorganic sealants have excellent stability and most of them are green and pollution-free, but their sealing performance is slightly poor.

[0005] In existing research, a patent application with the application number CN201510100842.9 discloses a method for preparing and applying a sealing agent. The components of the sealing agent include a phosphate compound, oxide particles, and water. Among them, the phosphate compound includes aluminum hydrogen phosphate, aluminum dihydrogen phosphate, or aluminum orthophosphate, and the oxide particles include alumina or silica. The oxide particles account for 2-30% of the mass of the phosphate compound, and the particle size of the oxide particles is 20-150 nm. This sealing agent is an inorganic sealing agent. After application, the high-temperature resistance of the coating is improved, and it has a certain moisture-resistant insulation effect. However, its penetration depth is relatively low, about 70 μm, and the resulting insufficiently dense filling degree cannot fully block the pores, the porosity does not decrease, and the corresponding corrosion resistance is poor, so the long-term effective service of the coating after sealing cannot be guaranteed. Most inorganic sealing agents are in the form of powder particles, and their loose structure and relatively poor fluidity limit their breakthroughs in terms of penetration depth and sealing performance. Some organic-inorganic composite sealing agents have a certain improvement in the filling degree, but some of the pores are filled loosely and the density is insufficient, and the corresponding barrier ability is not enough to inhibit the infiltration of corrosive media for a long time, and the long-term durability of the coating cannot be guaranteed. These problems have not been solved yet. Summary of the Invention

[0006] To solve the deficiencies of the existing technology, the present invention provides a ternary hybrid sealing agent, its preparation method and uses for this problem, realizing the combination of the high sealing performance of the organic sealing agent and the stability and wear resistance of the inorganic sealing agent. On this basis, graphene with a high specific surface area and excellent barrier performance is introduced to increase the penetration depth, and heterogeneous growth is achieved inside the coating to generate a composite structure with a high specific surface area, further improving the sealing performance and filling degree of the sealing agent, especially significantly improving the service durability of the coating.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A preparation method of a ternary hybrid sealing agent, comprising the following steps: ① Mix the waterborne organosilicon-modified acrylic resin with deionized water, and obtain solution A through homogenization treatment; ② Dissolve sodium molybdate and thiourea in deionized water, and stir to form a clear solution B; sodium molybdate and thiourea constitute a molybdenum disulfide precursor; ③ Take a surface modifier and add it to deionized water, and mix evenly to obtain solution C; ④ After mixing solutions A and C, continue stirring, and introduce the graphene oxide (GO) dispersion by the dropwise addition method to ensure the uniform dispersion of graphene oxide, and obtain the GO-modified A / C mixed system; ⑤ Slowly add solution B to the GO-modified A / C mixed system, and continue stirring to obtain a uniform and stable ternary hybrid sealing agent.

[0008] In a preferred embodiment, the mass ratio of the waterborne silicone-modified acrylic resin, the molybdenum disulfide precursor, and graphene oxide is 15-25:1-2:0.005.

[0009] Among them, the model of the waterborne silicone-modified acrylic resin is J-611, and the concentration of the graphene oxide dispersion is 4-6 mg / mL.

[0010] The present invention finds that the addition amount of graphene oxide affects the growth of molybdenum disulfide. The dosage of graphene oxide also has a great influence on the morphology, structure, and specific properties of the sealant formed when graphene oxide is used in combination with the waterborne silicone-modified acrylic resin and the molybdenum disulfide precursor. It is necessary to control the dosage of graphene oxide.

[0011] Furthermore, the ratio of the waterborne silicone-modified acrylic resin, the molybdenum disulfide precursor, the surfactant, and graphene oxide is: 15-25 g: 1-2 g: 1-2 mL: 0.005 g.

[0012] Preferably, in step ①, the ratio of the waterborne silicone-modified acrylic resin to deionized water is 15-25 g: 80-120 mL, and the time for homogenization treatment is 15-45 min.

[0013] In step ②, the mass ratio of sodium molybdate to thiourea is 1-2: 1-2; the mass ratio of the molybdenum disulfide precursor to deionized water is 1: 10-15; the stirring time is 20-30 min.

[0014] In step ③, the volume ratio of the surfactant to deionized water is 1.5: 5-15.

[0015] In step ④, after mixing solutions A and C, continue to stir for 20-40 min. After dropwise adding the graphene oxide dispersion, stir for 10-14 hours. Another object of the present invention is to disclose the ternary hybrid sealant prepared by the aforementioned preparation method.

[0016] Another object of the present invention is to provide the use of the aforementioned ternary hybrid sealant or its preparation method in the sealing of high-entropy alloy coatings.

[0017] Compared with the prior art, the present invention has the following beneficial effects: ①The present invention provides an organic-inorganic ternary hybrid sealant for high-entropy alloy coatings. The organic phase uses organosilicon-modified acrylic resin, which has the characteristics of being green, environmentally friendly, pollution-free, and having good heat resistance. Its good adsorption property makes it more stable when mixed with other materials, forming a uniform solution. The inorganic phase molybdenum disulfide is in-situ generated in the pores of the coating by hydrothermal reaction. Graphene oxide is mixed with the molybdenum disulfide precursor and organosilicon-modified acrylic resin to form a solution. Under the action of a surfactant, graphene oxide and the precursor are uniformly dispersed into the above resin successively. By means of ultrasonic oscillation and vacuum impregnation, the precursor sodium molybdate and thiourea penetrate into the pores deep in the coating. In the hydrothermal environment, graphene oxide forms a three-dimensional network structure, and the precursor reacts to generate molybdenum disulfide. The relatively excessive molybdenum disulfide grows heterogeneously on the graphene oxide sheets with a smaller amount, presenting three-dimensional filling inside the coating, and the penetration range is deeper and wider.

[0018] ②The nano-molybdenum disulfide in the sealant prepared by the present invention has excellent lubricating performance. During the use of the coating, when it is damaged by external force abrasion or erosion by corrosive media, etc., the molybdenum disulfide in the pores will be slowly released, continuously providing a lubricating phase on the surface to achieve the purpose of reducing friction. Organosilicon-modified acrylic resin and graphene oxide have excellent sealing and barrier properties. In the hydrothermal reaction kettle environment of high temperature and high pressure, an appropriate amount of water-based organosilicon-modified acrylic resin will carry the molybdenum disulfide precursor and graphene oxide to a deeper penetration depth. After hydrothermal treatment, molybdenum disulfide grows heterogeneously, forming a high specific surface area lamellar composite structure together with the graphene nanosheets and the resin matrix. This unique structure has excellent barrier properties and further improves the wear resistance, significantly enhancing the service durability of the high-entropy alloy coating. Description of the Drawings

[0019] Figure 1 Raman spectra of five MoS2 powders; Figure 2 SEM images of five MoS2: (a) M1; (b) M2; (c) M3; (d) M4; (e) M5; Figure 3 SEM images of two sealant materials: (a) SEM image of MoS2 / WBS-ACR powder; (b) SEM image of GO / MoS2 / WBS-ACR powder; Figure 4 Surface SEM images of coatings sealed with different sealants: (a) SEM image of MoS2 / WBS-ACR; (b) SEM image of GO / MoS2 / WBS-ACR; Figure 5 Friction coefficients of HEA coatings and coatings after being sealed with different sealants; Figure 6Polarization curve fitting parameters of different sealed specimens: (a) Corrosion potential; (b) Corrosion current density; Figure 7 Comparison of the actual appearance of the samples prepared in Example 1 and Comparative Example 3, (a) Comparative Example 3, (b) Example 1. Specific implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] In the present invention, the lubricating performance brought by the low shear strength and high stability of molybdenum disulfide is combined with the unique lamellar structure of graphene oxide to significantly reduce the porosity of the high-entropy coating. Among them, molybdenum disulfide is synthesized by one-step hydrothermal synthesis. As a typical layered transition metal sulfide, its crystal structure is composed of S-Mo-S sandwich units connected by strong covalent bonds and stacked by weak van der Waals forces, and there is a 1T phase (triangular coordination, metallicity). It is precisely this structure that brings excellent performance, and the nanoscale characteristics further enhance the lubricating performance and thermodynamic stability. The addition of graphene oxide not only serves as a lubricating and anti-friction phase, but also improves the overall uniformity of the solution due to a large number of oxygen-containing functional groups at the edges of its lamellae and good hydrophilicity, which helps the dispersion of the molybdenum disulfide precursor in the solution. At the same time, the large lamellar structure of graphene oxide helps the heterogeneous growth of molybdenum disulfide into a structure with a large specific surface energy during the hydrothermal process, and the resin and molybdenum disulfide grow on the surface of graphene oxide. These large-sized flakes are generated inside the pores of the coating, which not only ensures good filling but also isolates the intrusion of external corrosive media. On this basis, the hydrothermal synthesis process under different temperature-time gradients was also explored, and then an ultrasonic oscillation-vacuum impregnation cycle process was introduced to finally achieve high-position penetration and in-situ growth in the pores of the coating, and to explore the influence of different time-temperature gradients on the synthesis of molybdenum disulfide.

[0022] In this article, the Chinese and English names of some unsealed or sealed coatings are shown in Table 1.

[0023] Table 1 Chinese and English names of some unsealed or sealed coatings

[0024] In this paper, the high-entropy alloy coatings in the exploration examples, implementation examples, and comparative examples were sprayed using a plasma spraying testing machine. The high-entropy powder composition is Fe 22.01%, Co 23.67%, Ni 23.21%, Cr 20.16%, Al 10.84%, C 0.05%, S 0.06% (the percentages are mass fractions), and the plasma spraying parameters are: working voltage 40V, working distance 11mm, working current 500A, argon 50psi, powder feeding rate 1.6g / s, spray gun moving speed 100mm / s, 6 passes. The ternary hybrid sealant in this paper is not limited to the sealing of this kind of high-entropy alloy coating, but also applicable to the sealing of any other high-entropy alloy coatings.

[0025] Exploration Example 1 (1)Preparation of the precursor solution Weigh 0.800 g of sodium molybdate (MoNa2O4) and 0.887 g of thiourea (CH4N2S) as reaction precursors, and add them together with 80 ml of deionized water to a beaker. Under room temperature conditions, continuously stir with a magnetic stirrer for 30 minutes to ensure that the reactants are fully dissolved and mixed evenly, and finally obtain a stable molybdenum disulfide precursor solution.

[0026] (2)Application of the sealant ① After the high-entropy alloy coating specimen is pretreated (wire cutting, rust removal, grinding, degreasing, drying), place it in the above-prepared precursor solution for ultrasonic treatment for 30 minutes, and then transfer it to a vacuum drying oven together with the solution for vacuum impregnation at a pressure of -0.09 MPa for 30 minutes. These two steps are repeated 3 times each.

[0027] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle, and accurately control the reaction temperature and time parameters according to the experimental design. After the reaction kettle cools naturally, take out the sample and rinse it with deionized water to remove impurities. After drying in a drying oven at 60°C, grind to remove the excess sealant to obtain a clean and sealed high-entropy alloy coating.

[0028] Table 2 Coating name corresponding abbreviations and experimental setting parameters

[0029] Figure 1The results showed that in the time gradient experiment, the X-ray diffraction patterns of the M3-M5 samples were in good agreement with the standard cards. Among them, the M4 and M5 samples exhibited characteristic diffraction peaks of hexagonal MoS2 at the crystal plane orientations of 14.0° (002), 32.2° (100), and 57.6° (110). Notably, the diffraction peak of the (002) crystal plane of the M3 sample was significantly shifted from the standard value of 14.3° to 11.6°, indicating an expansion of its interlayer spacing. In the temperature gradient experiment, only the M3 sample could detect clear diffraction signals, and the M1-M2 samples did not show recognizable crystal plane characteristic peaks. This was due to the insufficient activation energy for the reaction between the molybdenum precursor and the sulfur source under low-temperature conditions, which inhibited the formation of MoS2 crystal nuclei.

[0030] The research results revealed that there was a synergistic regulation mechanism of reaction time and temperature on the crystal growth of MoS2: moderately extending the reaction time could promote the oriented stacking of the layered structure, and the temperature parameter needed to cross the critical threshold to activate the crystal nucleation process. It was worth noting that the 1T-phase characteristics were observed in the M3 sample, suggesting that a specific combination of reaction parameters could induce the transformation of MoS2 from the 2H phase to the 1T phase. This discovery provided a key experimental basis for the structural regulation of MoS2 and helped to precisely control its material properties.

[0031] Figure 2 The morphology evolution of MoS2 regulated by hydrothermal synthesis parameters was characterized by means of the SEM system. Figure 2 (a)-(c) in it revealed the law of the temperature gradient affecting the microstructure of MoS2: as the reaction temperature increased from 180 °C (M1) to 220 °C (M3), the morphology of MoS2 underwent an ordered structural transformation. At low temperature (M1), the product was amorphous particles with uneven particle sizes, rough surfaces, and agglomeration, which was consistent with the weak crystallization characteristics detected by XRD; when the temperature increased to 200 °C (M2), the particles initially showed the prototype of a rod-like structure; in the sample synthesized at 220 °C (M3), MoS2 exhibited a typical rod-like morphology. This temperature-dependent morphology transformation was thermodynamically driven. The high temperature enhanced the diffusion ability of the precursor ions, promoting the preferential growth of Mo-S coordination bonds along specific crystal planes to form a nanorod structure.

[0032] At a fixed temperature (220 °C), Figure 2 (c)-(e) in it showed the regulating effect of the reaction time gradient on the morphology of MoS2. As the reaction time increased from 18 h (M5) to 22 h (M3), the morphology of MoS2 underwent a reconstruction from a sheet-like to a rod-like structure. The M5 sample synthesized by reacting for 18 h was an assembly of wrinkled nanosheets, and a nanorod structure with a high axial ratio and a smooth surface was formed at 22 h (M3). The mechanism was that the initially high-concentration sulfur source promoted rapid nucleation to form a metastable sheet-like structure. As the reaction process accelerated, the system entered the thermodynamically dominant stage, and finally a thermodynamically stable anisotropic nanorod structure was formed.

[0033] The main conclusions on the influence law of the hydrothermal synthesis process of molybdenum disulfide under different temperature-time gradients are as follows: The hydrothermal reaction time-temperature gradient co-regulates the crystal phase composition and morphology of MoS2. When the reaction temperature reaches 220 °C and the time is extended to 22 h (sample M3), MoS2 presents a nanorod structure dominated by the 1T phase (accounting for 26%). XRD and Raman spectroscopy confirm that high temperature conditions (≥220 °C) are a necessary condition for triggering crystal nucleation, while long-time reaction (≥20 h) promotes the transformation from 2H to 1T phase by overcoming the phase transition activation energy. The SEM analysis results show that the formation of the nanorod structure originates from the thermodynamically dominated anisotropic growth mechanism. The high permeability of the nanorod structure and the high surface activity of the 1T and 2H phases contribute to the effective filling of the pores inside the coating.

[0034] Example 1

[0035] The use of a ternary hybrid sealing agent in sealing includes the following steps: (1) Preparation of the precursor solution ① Mix 20 g of WBS-ACR (model: J-611, manufacturer: Qingdao Jinwanli) with 100 mL of deionized water, and homogenize it at 500 r / min with a magnetic stirrer for 30 minutes to obtain solution A.

[0036] ② Dissolve 0.800 g of sodium molybdate and 0.887 g of thiourea in 20 mL of deionized water, and stir it at 500 r / min with a magnetic stirrer at room temperature for 30 minutes to form a clear solution B.

[0037] ③ Take a surface modifier (the surface modifier consists of defoamer BYK024, wetting and dispersing agent BYK156, and surfactant BYK346, manufacturer is BYK, and the added volumes of the three are 0.5 mL, 0.5 mL, and 0.5 mL respectively), add it to 10 mL of deionized water, and mix it evenly by vortex oscillation to obtain solution C.

[0038] ④ After mixing solutions A and C, continue to stir at 500 r / min for 30 minutes, introduce 1 mL of a 5 mg / mL graphene oxide (GO) dispersion by the dropwise addition method, and stir at 500 r / min for 12 hours to ensure the uniform dispersion of GO nanosheets.

[0039] ⑤ Slowly add solution B to the GO-modified A / C mixed system, and continue to stir at 500 r / min for 60 minutes to obtain a uniform and stable ternary hybrid sealing agent solution.

[0040] (2) Application of the sealing agent ① After the high-entropy alloy coating specimens (all high-entropy alloy coating specimens in this article are prepared by plasma spraying) are pretreated (wire cutting, rust removal, grinding, degreasing, drying), they are placed in the above-prepared ternary hybrid sealing agent solution and ultrasonically treated for 30 min. Subsequently, they are transferred to a vacuum drying oven with a pressure of -0.09 MPa together with the solution for vacuum impregnation for 30 min. The above two steps are repeated 3 times each.

[0041] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle and carry out a hydrothermal reaction at 220 °C for 22 hours. After the reaction kettle cools naturally, take out the sample and rinse it with deionized water to remove impurities. After drying in a drying oven at 60 °C, grind off the excess sealing agent to obtain a clean high-entropy alloy coating (GO / MoS2 / WBS-ACR @HEA) after sealing, completing the sealing process with the organic-inorganic ternary hybrid sealing agent.

[0042] Comparative Example 1 Use an inorganic sealing agent An application of an inorganic sealing agent in sealing includes the following steps: (1) Preparation of the precursor solution Weigh 0.800 g of sodium molybdate (MoNa2O4) and 0.887 g of thiourea (CH4N2S) as reaction precursors and dissolve them in 80 ml of deionized water. At room temperature, use a magnetic stirrer to continuously stir at 500 r / min for 30 minutes to ensure that the reactants are fully dissolved and mixed evenly, and finally obtain a stable molybdenum disulfide precursor solution.

[0043] (2) Application of the sealing agent ① After the high-entropy alloy coating specimens are pretreated (wire cutting, rust removal, grinding, degreasing, drying), they are placed in the above-prepared precursor solution and ultrasonically treated for 30 min. Subsequently, they are transferred to a vacuum drying oven with a pressure of -0.09 MPa together with the solution for vacuum impregnation for 30 min. The above two steps are repeated 3 times each.

[0044] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle and carry out a hydrothermal reaction at 220 °C for 22 hours. After the reaction kettle cools naturally, take out the sample and rinse it with deionized water to remove impurities. After drying in a drying oven at 60 °C, grind off the excess sealing agent to obtain a clean high-entropy alloy coating (MoS2@HEA) after sealing, completing the sealing process with the inorganic sealing agent.

[0045] Comparative Example 2 Use an organic-inorganic composite binary sealing agent An application of an organic-inorganic composite binary sealing agent in sealing includes the following steps: (1) Preparation of the precursor solution ① Mix 20 g of WBS-ACR with 100 mL of deionized water and treat it with a magnetic stirrer at 500 r / min for 30 minutes to obtain a uniform and stable Solution A.

[0046] ② Dissolve 0.800 g of sodium molybdate and 0.887 g of thiourea in 20 mL of deionized water, and stir with a magnetic stirrer at 500 r / min for 30 minutes at room temperature to form a clear Solution B.

[0047] ③ Take a surface modifier (the surface modifier consists of defoamer BYK024, wetting and dispersing agent BYK156, and surfactant BYK346, manufactured by BYK, and the added volumes of the three are 0.5 mL, 0.5 mL, and 0.5 mL respectively), add it to 10 mL of deionized water, and mix well by vortex oscillation to obtain Solution C.

[0048] ④ After mixing Solution A and Solution C and stirring at 500 r / min for 30 min, slowly add Solution B to the A / C mixed system, and continue to stir at 500 r / min for 60 min to obtain a uniform and stable binary hybrid sealing agent.

[0049] (2) Application of the sealing agent ① After the high-entropy alloy coating sample is pretreated (wire cutting, rust removal, grinding, degreasing, drying), place it in the above-prepared binary hybrid sealing agent solution and ultrasonically treat it for 30 min, then transfer it to a vacuum drying oven with a pressure of -0.09 MPa and vacuum impregnate it for 30 min. Repeat the above two steps 3 times each.

[0050] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle, and carry out a hydrothermal reaction at 220 °C for 22 hours. After the reaction kettle cools naturally, take out the sample, rinse it with deionized water to remove impurities, dry it in a drying oven at 60 °C, and then grind it to remove the excess sealing agent to obtain a clean high-entropy alloy coating (MoS2 / WBS-ACR @HEA) after sealing, completing the sealing process of the organic-inorganic composite binary hybrid sealing agent.

[0051] Comparative Example 3 Adjust the amount of graphene oxide An application of an organic-inorganic ternary hybrid sealing agent in sealing, including the following steps: (1) Preparation of the precursor solution ① Mix 20 g of WBS-ACR with 100 mL of deionized water, and homogenize it with a magnetic stirrer at 500 r / min for 30 minutes to obtain Solution A.

[0052] ② Dissolve 0.800 g of sodium molybdate and 0.887 g of thiourea in 20 mL of deionized water, and stir with a magnetic stirrer at 500 r / min for 30 minutes at room temperature to form a clear Solution B.

[0053] ③ Take the surface modifier (the surface modifier consists of defoamer BYK024, wetting and dispersing agent BYK156, and surfactant BYK346, manufactured by BYK, and the added volumes of the three are 0.5 mL, 0.5 mL, and 0.5 mL respectively), add it to 10 mL of deionized water, and prepare solution C by vortex mixing evenly.

[0054] ④ After mixing solutions A and C, continue stirring at 500 r / min for 30 minutes. Introduce 5 mL of graphene oxide (GO) dispersion with a concentration of 5 mg / mL by the dropwise addition method, and stir at 500 r / min for 12 hours to ensure the uniform dispersion of GO nanosheets.

[0055] ⑤ Slowly add solution B to the GO-modified A / C mixed system, and continue stirring at 500 r / min for 60 minutes to obtain a uniform and stable ternary hybrid sealing agent solution.

[0056] (2) Application of the sealing agent ① After the high-entropy alloy coating specimen is pretreated (wire cutting, rust removal, grinding, degreasing, drying), place it in the above-prepared mixed solution and ultrasonically treat it for 30 min. Subsequently, transfer it to a vacuum drying oven with a pressure of -0.09 MPa and vacuum impregnate it for 30 min. Repeat the above two steps 3 times each.

[0057] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle and carry out a hydrothermal reaction at 220 °C for 22 hours. After the reaction kettle cools naturally, take out the sample, rinse it with deionized water to remove impurities, dry it in a drying oven at 60 °C, and then grind it to remove the excess sealing agent to obtain a clean high-entropy alloy coating after sealing, completing the sealing process of the organic-inorganic ternary hybrid sealing agent.

[0058] Comparative Example 4 Adjust the resin dosage An application of an organic-inorganic ternary hybrid sealing agent in sealing, including the following steps: (1) Preparation of the precursor solution ① Mix 60 g of WBS-ACR with 100 mL of deionized water, and homogenize it at 500 r / min with a magnetic stirrer for 30 minutes to obtain solution A.

[0059] ② Dissolve 0.800 g of sodium molybdate and 0.887 g of thiourea in 20 mL of deionized water, and stir at 500 r / min with a magnetic stirrer at room temperature for 30 minutes to form a clear solution B.

[0060] ③ Respectively take 0.5 mL of surface modifier BYK024, BYK156, and BYK346 and add them to 10 mL of deionized water, and prepare solution C by vortex mixing evenly.

[0061] ④ Mix solutions A and C and continue stirring at 500 r / min for 30 minutes. Introduce 5 mL of a graphene oxide (GO) dispersion with a concentration of 5 mg / mL using the dropwise addition method, and stir at 500 r / min for 12 hours to ensure the uniform dispersion of GO nanosheets.

[0062] ⑤ Slowly add solution B to the GO-modified A / C mixed system and continue stirring at 500 r / min for 60 minutes to obtain a uniform and stable ternary hybrid sealing agent solution.

[0063] (2) Application of the sealing agent ① After pre-treating the high-entropy alloy coating specimens (wire cutting, rust removal, grinding, degreasing, drying), place them in the above-prepared mixed solution and ultrasonically treat for 30 min. Subsequently, transfer them to a vacuum drying oven with a pressure of -0.09 MPa and vacuum impregnate for 30 min. Repeat the above two steps three times each.

[0064] ② Transfer the solution and the sample to a polytetrafluoroethylene reaction kettle and carry out a hydrothermal reaction at 220 °C for 22 hours. After the reaction kettle cools naturally, take out the sample, rinse it with deionized water to remove impurities, dry it in a drying oven at 60 °C, and then grind to remove the excess sealing agent to obtain a clean high-entropy alloy coating after sealing, completing the sealing process of the organic-inorganic ternary hybrid sealing agent.

[0065] Figure 3 (a) in shows the scanning electron microscope (SEM) morphological characteristics of the binary hybrid sealing agent of acrylic resin modified with MoS2 (Comparative Example 2). It was observed that the rod-shaped MoS2 nanostructures were uniformly embedded in the resin matrix and were tightly wrapped, thus forming a composite structure with a three-dimensional elliptical appearance. These composite structures showed a random distribution, and the reason for their formation might be due to the action of the crystal orientation growth mechanism during the hydrothermal synthesis process. Such structural characteristics were of positive significance for enhancing the anti-permeability and interfacial bonding strength of the sealing agent in the coating. However, it was also observed from the figure that there was still a certain degree of agglomeration between MoS2 and the resin matrix. After introducing graphene, the structure of the hybrid system in Example 1 changed, specifically as Figure 3As shown in (b) thereof. Under the same magnification, the rod-like morphology of the original MoS2 has completely disappeared, and in its place is a layered composite structure formed synergistically by MoS2, graphene nanosheets and the resin matrix. The scanning electron microscope (SEM) image clearly shows that graphene is embedded in the resin matrix in the form of "wrinkled gauze", and the thickness of its lamellae has increased, which reflects the heteroepitaxial growth of MoS2 on the graphene lamellae. This morphological transformation is obviously beneficial to enhancing the sealing performance of the coating after sealing. Different from the prior art in which the heteroepitaxial growth of MoS2 on the graphene lamellae aims to increase the active sites of the material, improve hydrophilicity and conductivity, etc., the present invention promotes the enhancement of the sealing, long-term anti-corrosion and wear resistance of the coating after sealing by adding a small amount of graphene oxide embedded in the resin matrix and allowing relatively excessive MoS2 to grow heteroepitaxially on the graphene lamellae. When the relative amount of graphene oxide is increased, it has a significant impact on the specific structure formed by the heteroepitaxial growth of MoS2 on the graphene lamellae and the material properties.

[0066] by Figure 4 It can be seen that after the MoS2 / WBS-ACR binary hybrid sealant of Comparative Example 2 is disposed, the surface layer of the coating presents a continuous and dense sealant layer structure. Through in-depth observation, it can be found that the pores of the coating have been effectively filled, which reflects the excellent dispersibility and coverage of the sealant components on the coating surface. When graphene is introduced in Example 1 to construct a ternary hybrid sealant system, the microscopic morphology of the coating surface presents significant evolution characteristics. Although the binary hybrid sealant has strong pore filling efficiency, there are still a small number of pores that are not completely filled; while the ternary hybrid sealant layer shows a more dense and compact structure, and such structural optimization significantly improves the efficiency of the coating to resist the erosion of corrosive media, thereby further enhancing the sealing effect.

[0067] After the sealants of the above Example 1 and Comparative Examples 1-4 are used to treat the high-entropy alloy coating, the friction performance of the sealed coating samples is tested by a multifunctional friction tester of Lanzhou Huahui Instrument Co., Ltd., and the electrochemical performance is measured and analyzed by a Chenhua CHI660E electrochemical workstation. The solution is 3.5%wt NaCl, the porosity is observed by scanning electron microscopy and analyzed with the help of image J software; the penetration depth is observed by cross-sectional electron microscopy. All the tests are repeated three times, and the test results are the average of the three experiments. The porosities of the measured coatings are shown in Table 3.

[0068] Table 3 Porosities of HEA coatings and coatings after sealing treatment

[0069] Among them, the HEA coating is the unsealed high-entropy alloy coating sample, which is also the unsealed coating in Table 1.

[0070] It can be seen from the data in Table 3 that the porosity of the ternary hybrid sealing coating obtained in Example 1 (1.15±0.05%) shows a significant downward trend compared with the binary hybrid system (1.23±0.05%) of Comparative Example 2 and the inorganic sealing agent (1.65±0.10) of Comparative Example 1. Graphene oxide has a high specific surface area and a π-π conjugated structure, which can enhance the intermolecular forces between graphene oxide, MoS2 and resin, thereby improving the uniformity of the dispersion of MoS2 nanoparticles in the resin matrix; its mechanical properties can effectively curb the initiation of microcracks induced by resin shrinkage during the hydrothermal reaction process; more importantly, the layered structure of graphene can be stacked inside the pores, and the density of pore filling is significantly enhanced by the heterogeneous growth of MoS2 on the graphene sheets and the coating effect of the resin on graphene oxide and MoS2.

[0071] Comparative Examples 3 and 4 are both ternary hybrid systems like Example 1. By comparison, it is known that the amount of graphene oxide or resin relative to the molybdenum disulfide precursor has a significant effect on the porosity. The change in the amount of graphene oxide in Comparative Example 3 greatly improves the porosity, even higher than the binary hybrid system. The change in the amount of resin relative to the molybdenum disulfide precursor is also unfavorable to the porosity of the ternary hybrid system, which is related to the excessive amount of resin causing molybdenum disulfide to grow more between the resins and not be able to fully and uniformly grow heterogeneously on the graphene sheets.

[0072] The penetration depth of the ternary hybrid sealing coating obtained in Example 1 shows a significant improvement trend compared to Comparative Examples 1, 3, and 4. The penetration depth of the ternary hybrid sealing coating obtained in Example 1 is slightly improved compared to Comparative Example 2. Comparing Example 1 and Comparative Example 1, it can be seen that the addition of resin and graphene oxide significantly increases the penetration depth. Comparing Example 1 and Comparative Example 3, it can be seen that when the amount of graphene oxide changes, the penetration depth is significantly reduced. By comparing Comparative Example 1 and Comparative Example 3, the change in the amount of graphene oxide even almost offsets the positive effects of the resin and graphene oxide on the penetration depth. Comparing Example 1 and Comparative Example 4, it can be seen that when the amount of resin added is relatively large, the penetration depth of Comparative Example 4 is reduced.

[0073] The amount of graphene oxide or resin relative to the molybdenum disulfide precursor plays a key role in reducing porosity and / or increasing penetration depth. Comparing Example 1 and Comparative Example 3, it can be seen that the different amounts of graphene oxide lead to significantly uneven heterogeneous growth of MoS2 on graphene sheets. Comparing Example 1 and Comparative Example 4, it can be seen that the resin and the molybdenum disulfide precursor should meet certain ratio requirements. The ternary hybrid sealing agent of the present invention - resin / molybdenum disulfide / graphene oxide, relative to Comparative Example 4, obtains lower porosity and friction coefficient, as well as better long-term corrosion resistance effect at a lower relative amount of resin.

[0074] For example,Figure 7 For the comparison of the actual appearance of the samples prepared in Example 1 and Comparative Example 3, (a) is Comparative Example 3, and (b) is Example 1. It can be clearly seen from the figure that the surface of the sample prepared in Comparative Example 3 shows obvious agglomeration, wraps the specimen in a colloidal state, has low surface uniformity, and the sealant particles block the pores of the coating, resulting in insufficient penetration depth and sealing density of the sealant. In contrast, Example 1 shows a relatively flat surface covered with dark substances. The sealant on the coating surface is evenly dispersed and has good fluidity, which can penetrate into deeper pores, and almost all the visible pores on the surface are filled.

[0075] From Figure 5 it can be seen that the stable value of the friction coefficient of the as-sprayed HEA (i.e., the coatings in Figure 5 and Figure 6 ) without sealant is 0.57, which is closely related to the abrasive wear induced by the micro-pores on the coating surface and the local stress concentration effect. Although the friction coefficient of Comparative Example 1 is close to that of Example 1, its porosity is higher and the penetration depth is smaller, which significantly reduces the sealing performance and promotes corrosion. After the coating in Comparative Example 2 is treated with the MoS2 / WBS-ACR binary hybrid sealant, the friction coefficient of the coating is reduced to 0.32, a decrease of 43.9% compared with before. This indicates that the interlayer shear characteristics of MoS2 nanorods and the stress buffering synergistic effect of the resin matrix play a positive and effective role in inhibiting adhesive wear at the contact surface of the friction pair. When graphene oxide is introduced into Example 1 to construct the GO / MoS2 / WBS-ACR ternary hybrid system, the friction coefficient is further reduced to 0.24, a further decrease of 25% compared with the binary system. This optimization effect can be attributed to the specific hetero-layered structure formed by graphene nanosheets and MoS2 through π-π conjugation, which significantly enhances the shear stability of the interfacial slip layer.

[0076] Comparing Example 1 with Comparative Examples 3 and 4, all of which are ternary hybrid systems, it can be seen that different dosages of graphene oxide affect the shear stability of the interfacial slip layer and have a significant impact on the friction coefficient. Comparing Example 1 with Example 4, it can be seen that the change in the ratio of resin to molybdenum disulfide precursor also has a certain impact on the shear stability of the interfacial slip layer and the friction coefficient. The friction coefficient within 1 h increases in Comparative Example 4.

[0077] Analyzing from the evolution trend of the corrosion potential ( Figure 6 (a) in E corr ), the corrosion potential of the as-sprayed coating shows a rapid negative shift at the initial stage of immersion, indicating that the corrosive medium rapidly penetrates through the pores of the coating to the substrate interface, triggering a corrosion reaction. The E corrThe initial value (-0.64 V) shifted significantly positively, but shifted sharply negatively to -0.89 V after 168 h of immersion, corresponding to Figure 6 the (b) in i corr the stepwise increase in (corrosion current density), which is attributed to the swelling of the resin matrix and the hydrolysis failure of the MoS2 nanostructure in the long-term corrosion environment. However, the ternary hybrid system of Example 1 remained E corr near -0.62 V after 336 h of immersion, proving that the introduction of graphene oxide effectively inhibited the occurrence of the corrosion reaction. Among them Figure 6 the corrosion potential characterizes the corrosion tendency, and the corrosion current density characterizes the corrosion rate.

[0078] Comparing Example 1 with Comparative Examples 3 and 4 which are also ternary hybrid systems, it can be seen that the different dosages of graphene oxide in Comparative Example 3 significantly affected the short-term and long-term corrosion resistance of the coating, with the corrosion tendency being significantly greater than that of Example 1 and the current density (representing the corrosion rate) increasing significantly. Comparing Example 1 with Comparative Example 4 shows that the ratio of resin to molybdenum disulfide precursor also has a certain influence on the short-term and long-term corrosion resistance and corrosion tendency of the coating.

[0079] In summary, the foregoing content is only one of the many preferred specific embodiments of the present invention. However, the protection scope of the present invention is not limited thereto. Any professional person familiar with the technical field of this specialty, based on the technical framework and core concept disclosed by the present invention, and making improvements and optimizations to the present invention by means of equivalent substitution or equivalent transformation, should be included within the protection scope of the present invention.

Claims

1. A preparation method of a ternary hybrid sealing agent, characterized in that, It includes the following steps: ① Mix the waterborne silicone-modified acrylic resin with deionized water, and obtain solution A through homogenization treatment; ② Dissolve sodium molybdate and thiourea in deionized water, and stir to form a clear solution B; sodium molybdate and thiourea constitute the molybdenum disulfide precursor; ③ Take a surfactant and add it to deionized water, and mix evenly to prepare solution C; ④ Mix solutions A and C and continue stirring, and introduce the graphene oxide (GO) dispersion by the dropwise addition method to ensure the uniform dispersion of graphene oxide, and obtain the GO-modified A / C hybrid system; ⑤ Slowly add solution B to the GO-modified A / C hybrid system, and continue stirring to obtain a uniform and stable ternary hybrid sealing agent.

2. The preparation method of a ternary hybrid sealing agent according to claim 1, wherein The mass ratio of the waterborne silicone-modified acrylic resin, the molybdenum disulfide precursor and graphene oxide is 15~25:1~2:0.

005.

3. The preparation method of a ternary hybrid sealing agent according to claim 1, characterized in that, The model of the waterborne silicone-modified acrylic resin is J-611, and the concentration of the graphene oxide dispersion is 4-6 mg / mL.

4. The preparation method of a ternary hybrid sealing agent according to claim 1, characterized in that, The ratio of the waterborne silicone-modified acrylic resin, the molybdenum disulfide precursor, the surfactant and graphene oxide is: 15~25g:1~2g:1~2mL:0.005g.

5. The preparation method of a ternary hybrid sealing agent according to claim 1, characterized in that, In step ①, the ratio of the waterborne silicone-modified acrylic resin to deionized water is 15~25g:80~120mL, and the homogenization treatment time is 15~45min.

6. The preparation method of a ternary hybrid sealing agent according to claim 1, wherein, In step ②, the mass ratio of sodium molybdate to thiourea is 1~2:1~2; the mass ratio of the molybdenum disulfide precursor to deionized water is 1:10~15; the stirring time is 20~30min.

7. The preparation method of a ternary hybrid sealing agent according to claim 1, characterized in that, In step ③, the volume ratio of the surfactant to deionized water is 1.5:5-15.

8. The preparation method of a ternary hybrid sealing agent according to claim 1, characterized in that, In step ④, after mixing solutions A and C, continue stirring for 20~40min. After dropwise adding the graphene oxide dispersion, stir for 10~14 hours.

9. The ternary hybrid sealing agent prepared by the preparation method according to any one of claims 1~8.

10. The use of the ternary hybrid sealing agent according to claim 9 or the preparation method according to any one of claims 1~8 in the sealing of the high-entropy alloy coating.

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