High-temperature corrosion-resistant sealing wax as well as preparation method and application thereof

Abstract

The invention relates to the field of high-temperature corrosion-resistant materials, and particularly discloses high-temperature corrosion-resistant sealing wax as well as a preparation method and application thereof. The high-temperature corrosion-resistant sealing wax comprises the following raw material components in parts by mass: 20-50 parts of base wax, 10-30 parts of base oil, 5-10 parts of a thickening agent, 1-5 parts of a corrosion inhibitor, 1-3 parts of an anti-rust passivator, 1-3 parts of an antioxidant and 1-3 parts of a defoaming agent, wherein the basic wax comprises Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax; the base oil comprises poly alpha-olefin synthetic base oil and poly diisooctyl adipate; the corrosion inhibitor is prepared from 4-hydroxycinnamic acid rare earth salt and carboxylated graphene oxide. By utilizing the synergistic effect of various raw material components, the prepared high-temperature corrosion-resistant sealing wax has higher drop melting point, smaller needle penetration and excellent corrosion resistance, and can meet the use requirements of safety enclosure sealing of the nuclear power station.

Description

Technical Field

[0001] This invention relates to the field of high-temperature corrosion-inhibiting materials, and in particular to a high-temperature corrosion-inhibiting sealing wax, its preparation method, and its application. Background Technology

[0002] The nuclear power plant's safety enclosure is one of the outermost and most critical safety barriers of the reactor building. Its main function is to prevent the leakage of radioactive materials into the external environment during normal operation, accident conditions, and pressure tests. During periodic overhauls, pressure leak tests, and accident simulations, it is often necessary to create or utilize existing cable penetrations, measuring holes, test holes, and temporary openings in the safety enclosure for the installation of monitoring instruments, test pipelines, and ventilation equipment. These penetrations must be reliably temporarily sealed before and after the work is completed to ensure the overall airtightness and watertightness of the safety enclosure, preventing the uncontrolled migration of external moisture, corrosive media, and radioactive aerosols between different areas. Therefore, sealing materials specifically designed for these areas must not only possess excellent sealing performance but also ensure high-temperature stability, radiation resistance, and long-term corrosion resistance.

[0003] In current engineering practice, temporary sealing often uses petroleum-based sealing waxes or sealants. These materials are typically made primarily of microcrystalline wax, paraffin wax, or synthetic wax, combined with appropriate amounts of polymer thickeners, mineral oil or synthetic hydrocarbon base oils, rust inhibitors, antioxidants, and defoamers. The advantages of microcrystalline wax and mineral oil systems are mature technology and low cost. During operation, they only need to be heated to a molten state before being poured into the cavity, forming a solid plug upon cooling, providing a certain sealing effect in the short term. However, due to the physical limitations of the base wax and base oil, the dropping melting point is usually only around 100-110℃, and the penetration at room temperature is generally 60-90 (0.1 mm), classifying them as relatively soft waxes. In the actual operating environment of nuclear power plants, when there is a large temperature difference between the inside and outside of the containment or localized temperature increases, such as during high-temperature steam flushing, thermal functional testing, and the operation of the containment spray system, the sealing wax is prone to significant softening, flowing, and cold creep, leading to gaps at the edge of the sealing body and insufficient sealing reliability. At the same time, the wax body is also at risk of increased deformation, loosening and falling off under long-term load, which is not conducive to maintaining the integrity of the shell in the long term.

[0004] Furthermore, from a microstructural perspective, ordinary wax-based materials still contain numerous micropores, shrinkage voids, and microcracks after solidification. Insufficient wetting or poor adhesion often exists between the interface transition zone and the sealed metal surface. Salt spray, condensate, and chloride-containing condensate can gradually penetrate along these micro-defects, forming capillary-like diffusion paths. This causes corrosive media to remain at the wax-metal interface for extended periods, leading to pitting corrosion, crevice corrosion, and even flaking. While the surface of the sealing wax remains intact, the underlying metal has already suffered severe corrosion. To enhance corrosion resistance, existing sealing waxes commonly incorporate inorganic rust inhibitors such as chromates and barium salts, or organic salt systems containing heavy metals. While these components can provide some passivation to carbon steel substrates in the short term, they themselves possess high toxicity and bioaccumulation potential. Improper handling can easily pose potential hazards to operator health and the plant environment.

[0005] Therefore, developing a new type of sealing wax material with a higher melting point, smaller penetration, better corrosion resistance, and no highly toxic heavy metal components is of great practical significance for significantly improving the sealing reliability and service life of key parts of the nuclear power plant's safety enclosure. Summary of the Invention

[0006] In view of this, the present invention provides a high-temperature corrosion-inhibiting sealing wax, its preparation method, and its application. The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components: base wax, base oil, thickener, corrosion inhibitor, rust inhibitor / passivator, and defoamer; wherein the base wax includes Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax; the base oil includes polyalphaolefin synthetic base oil and poly(diisooctyl adipate); and the corrosion inhibitor includes rare earth salt of 4-hydroxycinnamate and carboxylated graphene oxide. The present invention utilizes the synergistic effect of multiple raw material components to endow the prepared high-temperature corrosion-inhibiting sealing wax with a high dropping melting point, lower penetration, and excellent corrosion resistance, which can meet the requirements for sealing the safety enclosure of nuclear power plants.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a high-temperature corrosion-inhibiting sealing wax, comprising the following raw material components in parts by weight: 20-50 parts of base wax, 10-30 parts of base oil, 5-10 parts of thickener, 1-5 parts of corrosion inhibitor, 1-3 parts of rust-preventing and passivating agent, 1-3 parts of antioxidant and 1-3 parts of defoamer. The base wax includes Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax; the base oil includes polyalphaolefin synthetic base oil and poly(diisooctyl adipate); and the corrosion inhibitor includes rare earth salt of 4-hydroxycinnamate and carboxylated graphene oxide.

[0008] Compared to existing technologies, the high-temperature corrosion-inhibiting sealing wax proposed in this invention forms a stable three-dimensional spatial network and a three-dimensional corrosion-inhibiting system among its components. This synergistically solves the technical problems of existing nuclear power plant safety enclosure sealing waxes, such as insufficient high-temperature resistance, numerous internal defects, limited corrosion protection capabilities, and poor environmental performance. Specifically, this invention selects Fischer-Tropsch synthetic wax with a high dropping melting point, low penetration, and low oil content as the skeleton wax in the system. This significantly increases the overall dropping melting point of the finished sealing wax, ensuring that the material maintains a solid structure and high yield strength above 110°C. This prevents the sealing body from collapsing or shifting due to softening or flowing under conditions such as nuclear power plant thermal functional tests, high-temperature steam flushing, and containment spraying. Furthermore, this invention uses hydrogenated microcrystalline wax as a supplementary wax. With its smaller grain size and suitable melting point range, it fills and toughens the spaces between Fischer-Tropsch wax crystals, reducing the brittleness of a single high-melting-point wax and minimizing micropores and microcracks formed by cooling shrinkage. This improves the overall density and impact resistance of the material, preventing brittleness and detachment under low-temperature and thermal cycling conditions.

[0009] Polyalphaolefin (PAO) synthetic base oil and poly(diisooctyl adipate) together constitute the wetting and flexibility conditioning system in the wax phase. PAO base oil, with its high viscosity index, low pour point, and low volatility, allows the sealing wax to maintain a certain degree of flexibility at low temperatures, preventing cracking caused by an excessively rigid wax phase. Simultaneously, unlike mineral oil, it does not evaporate or seep excessively at medium to high temperatures, avoiding internal volume shrinkage and structural loosening. Poly(diisooctyl adipate) significantly improves the wetting and impregnation capabilities of the molten system on concrete pore walls and metal surfaces, enabling the sealing wax to fully fill pores and irregular depressions, reducing voids and capillary gaps at interfaces, and providing a continuous and dense matrix environment for subsequent anti-corrosion systems.

[0010] This invention also introduces a thickener between the skeleton wax and the base oil, constructing a three-dimensional network structure that runs through the entire wax-based system. This network effectively improves the yield stress and shear modulus of the sealing wax, fundamentally enhancing its load-bearing capacity and creep resistance. Furthermore, it imparts significant thixotropy to the material, exhibiting good fluidity and self-compacting ability during heating or application, and rapidly recovering high modulus and high strength upon cooling, thus balancing ease of application with service life stability. Through the synergistic design of the skeleton wax-base oil-thickener, the sealing wax obtained by this invention possesses advantages such as non-flowing at high temperatures, non-brittleness at low temperatures, and no cold flow over long periods.

[0011] To meet corrosion protection requirements, this invention selects 4-hydroxycinnamic acid rare earth salt as the core corrosion inhibitor. This type of rare earth carboxylate exhibits excellent adsorption and coordination capabilities at the coating / metal interface, forming a dense and insoluble rare earth organic complex film on the steel surface. This effectively inhibits anodic dissolution and cathodic oxygen reduction reactions, thereby significantly reducing corrosion current density. Compared to traditional chromate and barium salt rust inhibitors, rare earth organic corrosion inhibitors do not contain highly toxic heavy metals, posing less environmental and health risks and meeting the requirements of nuclear power plants for green and environmentally friendly materials.

[0012] Carboxylated graphene oxide, as a two-dimensional sheet-like shielding filler, readily forms a "brick-wall" labyrinth structure within a wax / oil matrix due to its high aspect ratio and layered structure. Corrosive media (such as water, oxygen, and chloride ions) must navigate the long paths created by the graphene oxide sheets when passing through the coating, significantly increasing the diffusion distance and time, thereby effectively reducing the penetration rate of the media to the metal surface. Simultaneously, the introduction of polar functional groups such as carboxyl groups onto the surface of aminated graphene oxide greatly enhances its compatibility and interfacial bonding with rare earth organic salts and thickening polymers. This allows for the localized enrichment of rare earth ions, enhancing their adsorption effect and organically combining the chemical passivation film with the physical shielding layer to form a three-dimensional corrosion inhibition system of "chemical passivation + physical barrier."

[0013] Furthermore, since the sealing wax is exposed to a certain temperature and oxygen environment for extended periods during its service in nuclear power plants, without an effective antioxidant system, the wax phase, base oil, and resin components will undergo thermo-oxidative aging, generating acidic or polar degradation products. This not only leads to material brittleness, cracking, and pulverization but also accelerates metal corrosion, severely shortening the sealing life. This invention also incorporates rust inhibitors and passivators, enabling the sealing wax to quickly form a hydrophobic anti-rust film on the metal surface, meeting the protection requirements of multi-metal assemblies in nuclear power plants. The addition of antioxidants helps maintain a neutral or slightly alkaline interface environment, further improving the corrosion safety margin of the metal substrate. The addition of defoamers, on the one hand, avoids salt spray penetration short circuits caused by pores, ensuring the integrity of the shielding layer; on the other hand, it improves the performance consistency of different batches of products and different application sites, giving the sealing wax of this invention better reliability and a longer service life in engineering applications.

[0014] Preferably, the base wax comprises Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2:1 to 3:1.

[0015] Preferably, the base oil comprises polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1 to 1:1.5.

[0016] Preferably, the corrosion inhibitor comprises rare earth 4-hydroxycinnamic acid salt and carboxylated graphene oxide in a mass ratio of 1:1 to 2:1.

[0017] Preferably, the Fischer-Tropsch synthetic wax is one or more of the following: W-105, W-80, or WL-115.

[0018] Preferably, the hydrogenated microcrystalline wax has a melting point of 80-90°C and an oil content of 1%-2%.

[0019] Preferably, the viscosity index of the polyalphaolefin synthetic base oil is 130-170.

[0020] Preferably, the rare earth salt of 4-hydroxycinnamate is cerium 4-hydroxycinnamate or lanthanum 4-hydroxycinnamate.

[0021] Preferably, the preparation method of the 4-hydroxycinnamic acid rare earth salt includes the following steps: dissolving 4-hydroxycinnamic acid in an alcohol solution, adding a rare earth salt solution, controlling the pH to 4-5, allowing it to stand, separating the solid and liquid, and drying to obtain the 4-hydroxycinnamic acid rare earth salt.

[0022] More preferably, the mass-to-volume ratio of the 4-hydroxycinnamic acid to the alcohol solution is 1g:3mL-1g:5mL; wherein the alcohol solution is an ethanol solution with a mass fraction of 75%-80%.

[0023] More preferably, the concentration of the rare earth salt solution is 1-2 mol / L.

[0024] More preferably, the molar ratio of rare earth ions in the rare earth salt solution to that of 4-hydroxycinnamic acid is 1:1 to 1.2:1.

[0025] Preferably, the preparation method of the carboxylated graphene oxide includes the following steps: dispersing graphene oxide in deionized water to obtain a suspension; adding chloroacetic acid and an inorganic base to the suspension, reacting at 60-80°C, separating the solid and liquid, washing, and drying to obtain the carboxylated graphene oxide.

[0026] More preferably, the mass-to-volume ratio of the graphene oxide to the deionized water is 1g:3mL-1g:5mL.

[0027] More preferably, the amount of chloroacetic acid added is 5%-10% of the mass of the graphene oxide.

[0028] More preferably, the amount of inorganic base added is 3%-5% of the mass of the graphene oxide.

[0029] More preferably, the reaction time is 4-6 hours.

[0030] Preferably, the thickener is one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted ethylene-propylene copolymer, or polyisobutylene.

[0031] More preferably, the thickener is maleic anhydride-grafted polypropylene.

[0032] Preferably, the rust inhibitor and passivator is a mixture of calcium petroleum sulfonate and benzotriazole.

[0033] More preferably, the mass ratio of calcium petroleum sulfonate and benzotriazole in the rust inhibitor and passivator is 1:1 to 1:1.5.

[0034] Preferably, the antioxidant is di-tert-butyl-p-cresol.

[0035] Preferably, the defoamer is a polyether-modified silicone defoamer.

[0036] A second aspect of this invention provides a method for preparing the aforementioned high-temperature corrosion-inhibiting sealing wax, comprising the following steps: Step 1: Mix the base waxes, heat to 130-150℃, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 120-130℃, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 100-110℃, add defoamer, mix evenly, and cool to obtain high temperature corrosion-resistant sealing wax.

[0037] The third aspect of this invention provides the application of the aforementioned high-temperature corrosion-inhibiting sealing wax in the preparation of sealing materials for the safety enclosure of nuclear power plants.

[0038] In summary, this invention, through meticulous design of the basic system including base wax, base oil, and corrosion inhibitors, achieves high dimensional stability in the resulting high-temperature corrosion-inhibiting sealing wax, ensuring it does not flow under high-temperature conditions, does not crack under low-temperature conditions, and does not experience cold flow during long-term service. Furthermore, it constructs a three-dimensional corrosion-inhibiting system combining chemical passivation and physical shielding, significantly improving the corrosion resistance of the high-temperature corrosion-inhibiting sealing wax. The addition of an antioxidant aging system and an anti-foaming system ensures the material's internal density, uniform structure, and long-term performance without degradation. It is precisely the synergistic effect between the components that makes the high-temperature corrosion-inhibiting sealing wax of this invention significantly effective in key indicators such as dropping point, penetration, and salt spray corrosion resistance life, effectively solving the technical problems of poor temperature resistance, insufficient corrosion inhibition capacity, and poor environmental friendliness of traditional nuclear power plant safety enclosure sealing waxes. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The hydrogenated microcrystalline wax used in the following examples and comparative examples has a dropping melting point of 87°C and an oil content of 2%.

[0041] The viscosity index of the polyalphaolefin synthetic base oil used in the following examples and comparative examples is 150.

[0042] Unless otherwise specified, the poly(diisooctyl adipate), calcium petroleum sulfonate, benzotriazole, di-tert-butyl-p-cresol, and polyether-modified silicone defoamer used in the following examples and comparative examples are all commercially available products.

[0043] Example 1 This embodiment provides a high-temperature corrosion-inhibiting sealing wax and its preparation method, specifically including the following steps: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 35 parts base wax, 18 parts base oil, 6 parts maleic anhydride-grafted polypropylene, 4 parts corrosion inhibitor, 3 parts rust-preventing and passivating agent, 2 parts di-tert-butyl-p-cresol, and 2 parts polyether-modified silicone defoamer; wherein, the base wax is WL-115 Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2.5:1; the base oil is polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1; the corrosion inhibitor is cerium 4-hydroxycinnamate and carboxylated graphene oxide in a mass ratio of 1.5:1; and the rust-preventing and passivating agent contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.2.

[0044] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Mix the base waxes, heat to 145°C, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 122°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 105°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the cerium 4-hydroxycinnamate includes the following steps: 10g of 4-hydroxycinnamic acid was dissolved in 40mL of 80% ethanol solution, and 61mL of 1mol / L cerium chloride was added. The pH was controlled at 4.8, and a large amount of precipitate appeared. After standing for 3h, the solid and liquid were separated, washed, and dried to obtain the cerium 4-hydroxycinnamic acid.

[0045] The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0046] Example 2 This embodiment provides a high-temperature corrosion-inhibiting sealing wax and its preparation method, specifically including the following steps: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 40 parts base wax, 20 parts base oil, 5 parts maleic anhydride-grafted polypropylene, 3 parts corrosion inhibitor, 2 parts rust-preventing and passivating agent, 3 parts di-tert-butyl-p-cresol, and 3 parts polyether-modified silicone defoamer; wherein, the base wax is WL-115 Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2:1; the base oil is polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1.5; the corrosion inhibitor is cerium 4-hydroxycinnamate and carboxylated graphene oxide in a mass ratio of 1:1; and the rust-preventing and passivating agent contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.

[0047] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Mix the base waxes, heat to 140°C, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 128°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 100°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the cerium 4-hydroxycinnamate includes the following steps: 10g of 4-hydroxycinnamic acid was dissolved in 40mL of 80% ethanol solution, and 61mL of 1mol / L cerium chloride was added. The pH was controlled at 4.8, and a large amount of precipitate appeared. After standing for 3h, the solid and liquid were separated, washed, and dried to obtain the cerium 4-hydroxycinnamic acid.

[0048] The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0049] Example 3 This embodiment provides a high-temperature corrosion-inhibiting sealing wax and its preparation method, specifically including the following steps: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 50 parts base wax, 10 parts base oil, 10 parts maleic anhydride-grafted polypropylene, 2 parts corrosion inhibitor, 3 parts rust-preventing and passivating agent, 2 parts di-tert-butyl-p-cresol, and 2 parts polyether-modified silicone defoamer; wherein, the base wax is W-105 Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 3:1; the base oil is polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1.5; the corrosion inhibitor is cerium 4-hydroxycinnamate and carboxylated graphene oxide in a mass ratio of 2:1; and the rust-preventing and passivating agent contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.2.

[0050] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Mix the base waxes, heat to 138°C, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture system, cool to 120°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 102°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the cerium 4-hydroxycinnamate includes the following steps: 10g of 4-hydroxycinnamic acid was dissolved in 40mL of 80% ethanol solution, and 61mL of 1mol / L cerium chloride was added. The pH was controlled at 4.8, and a large amount of precipitate appeared. After standing for 3h, the solid and liquid were separated, washed, and dried to obtain the cerium 4-hydroxycinnamic acid.

[0051] The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0052] Comparative Example 1 This comparative example provides a lubricating grease and its preparation method, which differs from Example 1 in that the base wax is only a Fischer-Tropsch synthetic wax, while other components and processes remain unchanged, specifically including the following: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 35 parts WL-115 Fischer-Tropsch synthetic wax, 18 parts base oil, 6 parts maleic anhydride-grafted polypropylene, 4 parts corrosion inhibitor, 3 parts rust-inhibiting and passivating agent, 2 parts di-tert-butyl-p-cresol, and 2 parts polyether-modified silicone defoamer; wherein, the base wax is WL-115 Fischer-Tropsch synthetic wax; the base oil is a 1:1 mass ratio of polyalphaolefin synthetic base oil and poly(diisooctyl adipate); the corrosion inhibitor is a 1.5:1 mass ratio of cerium 4-hydroxycinnamate and carboxylated graphene oxide; and the rust-inhibiting and passivating agent contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.2.

[0053] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Heat the Fischer-Tropsch wax to 145°C, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 122°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 105°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the cerium 4-hydroxycinnamate includes the following steps: 10g of 4-hydroxycinnamic acid was dissolved in 40mL of 80% ethanol solution, and 61mL of 1mol / L cerium chloride was added. The pH was controlled at 4.8, and a large amount of precipitate appeared. After standing for 3h, the solid and liquid were separated, washed, and dried to obtain the cerium 4-hydroxycinnamic acid.

[0054] The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0055] Comparative Example 2 This comparative example provides a lubricating grease and its preparation method, which differs from Example 1 in that the base oil is replaced with an equal amount of BS series mineral oil (BS927 mineral oil), while other components and processes remain unchanged. Specifically, it includes the following: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 35 parts base wax, 18 parts BS series mineral oil, 6 parts maleic anhydride-grafted polypropylene, 4 parts corrosion inhibitor, 3 parts rust-inhibiting passivator, 2 parts di-tert-butyl-p-cresol, and 2 parts polyether-modified silicone defoamer; wherein the base wax is WL-115 Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2.5:1; the base oil is BS927 mineral oil; the corrosion inhibitor is cerium 4-hydroxycinnamate and carboxylated graphene oxide in a mass ratio of 1.5:1; and the rust-inhibiting passivator contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.2.

[0056] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Mix the base waxes, heat to 145°C, add BS mineral oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 122°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 105°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the cerium 4-hydroxycinnamate includes the following steps: 10g of 4-hydroxycinnamic acid was dissolved in 40mL of 80% ethanol solution, and 61mL of 1mol / L cerium chloride was added. The pH was controlled at 4.8, and a large amount of precipitate appeared. After standing for 3h, the solid and liquid were separated, washed, and dried to obtain the cerium 4-hydroxycinnamic acid.

[0057] The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0058] Comparative Example 3 This comparative example provides a lubricating grease and its preparation method, which differs from Example 1 in that the corrosion inhibitor is replaced with an equal amount of carboxylated graphene oxide, while other components and processes remain unchanged. Specifically, it includes the following: The high-temperature corrosion-inhibiting sealing wax comprises the following raw material components in parts by weight: 35 parts base wax, 18 parts base oil, 6 parts maleic anhydride-grafted polypropylene, 4 parts carboxylated graphene oxide, 3 parts rust inhibitor and passivator, 2 parts di-tert-butyl-p-cresol, and 2 parts polyether-modified silicone defoamer; wherein the base wax is WL-115 Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2.5:1; the base oil is polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1; and the rust inhibitor and passivator contains calcium petroleum sulfonate and benzotriazole in a mass ratio of 1:1.2.

[0059] The preparation method of the high-temperature corrosion-inhibiting sealing wax includes the following steps: Step 1: Mix the base waxes, heat to 145°C, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 122°C, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 105°C, add defoamer, mix evenly, and cool to obtain the high-temperature corrosion-resistant sealing wax. The preparation method of the carboxylated graphene oxide includes the following steps: 10g of graphene oxide was dispersed in 50mL of deionized water to obtain a suspension; 0.8g of chloroacetic acid and 0.4g of sodium hydroxide were added to the suspension and reacted at 70℃ for 5h. The solid and liquid were separated, washed, and dried to obtain the carboxylated graphene oxide.

[0060] To further demonstrate the technical effects of the present invention, the high-temperature corrosion-inhibiting sealing waxes obtained in Examples 1-3 and Comparative Examples 1-3 were tested as follows: the dropping point was tested according to GB / T 4929-1985 at 25℃, 100 g, and 5 s; the penetration test was conducted according to GB / T4985-2021; and the salt spray test was conducted with reference to SH / T0081. After cleaning and drying the surface of the shot-blasted Q235 steel plate, a sealing wax of the present invention with a thickness of about 2-3 mm was coated on one side. After curing at room temperature for 24 h, it was placed in a neutral salt spray test chamber. The test conditions were: 5% sodium chloride aqueous solution, pH adjusted to 7.0, test temperature 36℃, continuous spraying, and the samples were periodically taken out to observe the corrosion, blistering, and coating damage. The time when obvious red rust appeared or the blistering area of ​​the coating reached the specified level was taken as the failure time. The test results are shown in Table 1.

[0061] Table 1 Performance Test Results

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature corrosion-inhibiting sealing wax, characterized in that: The raw material components include the following parts by weight: 20-50 parts base wax, 10-30 parts base oil, 5-10 parts thickener, 1-5 parts corrosion inhibitor, 1-3 parts rust inhibitor and passivator, 1-3 parts antioxidant and 1-3 parts defoamer; The base wax includes Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax; the base oil includes polyalphaolefin synthetic base oil and poly(diisooctyl adipate); and the corrosion inhibitor includes rare earth salt of 4-hydroxycinnamate and carboxylated graphene oxide.

2. The high-temperature corrosion-inhibiting sealing wax as described in claim 1, characterized in that: The base wax comprises Fischer-Tropsch synthetic wax and hydrogenated microcrystalline wax in a mass ratio of 2:1 to 3:1; The base oil comprises polyalphaolefin synthetic base oil and poly(diisooctyl adipate) in a mass ratio of 1:1 to 1:1.5; The corrosion inhibitor comprises rare earth salts of 4-hydroxycinnamate and carboxylated graphene oxide in a mass ratio of 1:1 to 2:

1.

3. The high-temperature corrosion-inhibiting sealing wax as described in claim 1 or 2, characterized in that: The Fischer-Tropsch synthetic wax is one or more of the following: W-105, W-80, or WL-115; The hydrogenated microcrystalline wax has a melting point of 80-90℃ and an oil content of 1%-2%. The viscosity index of the polyalphaolefin synthetic base oil is 130-170.

4. The high-temperature corrosion-inhibiting sealing wax as described in claim 1 or 2, characterized in that: The rare earth salt of 4-hydroxycinnamate is cerium 4-hydroxycinnamate or lanthanum 4-hydroxycinnamate.

5. The high-temperature corrosion-inhibiting sealing wax as described in claim 4, characterized in that: The preparation method of the 4-hydroxycinnamic acid rare earth salt includes the following steps: dissolving 4-hydroxycinnamic acid in an alcohol solution, adding a rare earth salt solution, controlling the pH to 4-5, allowing it to stand, separating the solid and liquid, and drying to obtain the 4-hydroxycinnamic acid rare earth salt.

6. The high-temperature corrosion-inhibiting sealing wax as described in claim 5, characterized in that: The mass-to-volume ratio of the 4-hydroxycinnamic acid to the alcohol solution is 1g:3mL to 1g:5mL; wherein the alcohol solution is an ethanol solution with a mass fraction of 75%-80%. The concentration of the rare earth salt solution is 1-2 mol / L; The molar ratio of rare earth ions in the rare earth salt solution to that of 4-hydroxycinnamic acid is 1:1 to 1.2:

1.

7. The high-temperature corrosion-inhibiting sealing wax as described in claim 3, characterized in that: The preparation method of the carboxylated graphene oxide includes the following steps: dispersing graphene oxide in deionized water to obtain a suspension; adding chloroacetic acid and an inorganic base to the suspension, reacting at 60-80℃, separating the solid and liquid, washing, and drying to obtain the carboxylated graphene oxide.

8. The high-temperature corrosion-inhibiting sealing wax as described in claim 7, characterized in that: The mass-to-volume ratio of the graphene oxide to the deionized water is 1g:3mL-1g:5mL; The amount of chloroacetic acid added is 5%-10% of the mass of the graphene oxide; The amount of inorganic base added is 3%-5% of the mass of the graphene oxide; The reaction time is 4-6 hours.

9. A method for preparing a high-temperature corrosion-inhibiting sealing wax as described in any one of claims 1-8, characterized in that: Includes the following steps: Step 1: Mix the base waxes, heat to 130-150℃, add the base oil and thickener, mix well to obtain the first mixture system; Step 2: Add corrosion inhibitor to the first mixture, cool to 120-130℃, add rust inhibitor and passivator and antioxidant, mix evenly, cool to 100-110℃, add defoamer, mix evenly, and cool to obtain high temperature corrosion-resistant sealing wax.

10. The application of the high-temperature corrosion-inhibiting sealing wax as described in any one of claims 1-8 in the preparation of sealing materials for the safety enclosure of nuclear power plants.

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