A rust-preventive coating composition, a method for producing the same, and use thereof

Abstract

The present application belongs to the technical field of rust-proof coating, and provides a rust-proof coating composition, a preparation method and application thereof; firstly, a BiVO4 composite material with high thermal stability and oxygen vacancy structure is prepared by a hydrothermal method to enhance its thermal stress resistance and mechanical strength; secondly, a chlorinated phosphazene polymer composite is prepared by an anhydrous ethanol dispersion polymerization method to improve the chemical corrosion resistance and thermal stability of the coating; then, a glass ceramic containing phosphate reinforcement is prepared to improve the mechanical properties and high-temperature resistance of the coating; finally, the above functional materials, modified resin and phosphate ester coupling agent are mixed and uniformly dispersed by a three-roll grinding machine to obtain the corrosion-resistant coating composition; the coating exhibits excellent thermal stress resistance under high-temperature conditions, can effectively inhibit the occurrence of coating cracking, falling and corrosion, improves the service life of high-temperature transportation pipelines, and is suitable for the field of high-temperature pipelines / pipes.

Description

Technical Field

[0001] This invention belongs to the field of anti-rust coating technology, and relates to an anti-rust coating composition, its preparation method and application. Background Technology

[0002] With rapid industrialization, high-temperature transportation pipelines have been widely used in petrochemical, natural gas transmission, and energy equipment. However, under the long-term effects of high temperature, high pressure, and corrosive media, the pipeline surface is highly susceptible to corrosion due to the harsh environment, leading to decreased equipment performance, shortened service life, and even serious safety hazards. Especially under extreme temperature conditions, the anti-corrosion coating on the pipeline surface frequently faces the risk of failure. High-temperature environments cause thermal expansion and contraction of the coating, resulting in accumulated thermal stress, which in turn causes cracking, delamination, or peeling of the coating. This not only accelerates the corrosion process of the substrate but also further threatens the safety and stability of the facilities.

[0003] Traditional coating systems primarily rely on single organic resins or inorganic fillers. However, these materials have significant limitations in heat resistance, crack resistance, and adhesion, failing to meet the requirements for long-term use in high-temperature transportation pipelines. Furthermore, chemically corrosive media at extreme temperatures can further exacerbate interfacial damage between the coating and the substrate, significantly reducing the coating's protective performance. Therefore, developing a corrosion-resistant coating material that maintains long-term stability, exhibits excellent corrosion protection, and possesses good mechanical properties under high-temperature environments is of significant practical importance for the reliable operation of high-temperature industrial equipment and for extending its service life. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a rust-preventive coating composition, its preparation method, and its application. This invention introduces multifunctional components such as BiVO4 composite material, chlorinated phosphazene polymer composite, and glass ceramics to construct a coating system with excellent thermal stability, mechanical strength, and corrosion resistance. The BiVO4 composite material is prepared via a hydrothermal method, possessing oxygen vacancies and good thermal stress regulation capabilities; the chlorinated phosphazene polymer composite provides chemical corrosion resistance and thermal stability; and the glass ceramics, through high-temperature melting and ammonia treatment, enhance the coating's crack resistance and high-temperature resistance. These multi-components are dispersed and uniformly mixed using a modified resin and a phosphate ester coupling agent to form a high-temperature protective coating, thereby meeting the needs of practical production.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a rust-preventive coating composition, the method comprising:

[0007] A1. Bismuth nitrate pentahydrate was dispersed in nitric acid solution to obtain bismuth solution. Ammonium metavanadate was dispersed in sodium hydroxide solution and added to bismuth solution for hydrothermal reaction to obtain BiVO4. BiVO4 was placed in a tube furnace and heated by passing a mixed gas to obtain BiVO4-δ. α-Zrconium phosphate was mixed with BiVO4-δ, ball-milled, and then immersed in sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0008] S1, 4,4'-difluorobenzophenone and 4,4'-biphenylhydroquinone are dispersed in sulfolane and potassium carbonate is added to react. Pentafluorophenyltriethoxysilane is added to continue the reaction to obtain a modified resin. The modified resin is dispersed in N-methylpyrrolidone to obtain a resin solution.

[0009] S2, BiVO4 composite material, chlorinated phosphazene polymer composite, glass ceramic and phosphate coupling agent are dispersed in N-methylpyrrolidone, ultrasonically dispersed and then added to resin solution to obtain a rust-preventive coating composition.

[0010] Specifically, it includes:

[0011] A1. Bismuth nitrate pentahydrate was dispersed in nitric acid solution to obtain bismuth solution. Ammonium metavanadate was dispersed in sodium hydroxide solution and added to the bismuth solution. The pH was adjusted to 2.0-2.5. The mixture was then transferred to a polytetrafluoroethylene-lined reactor for hydrothermal reaction. After drying, BiVO4 was obtained. BiVO4 was placed in a tube furnace, a mixed gas was introduced, and the temperature was raised to the first temperature and held to obtain BiVO4-δ. α-Zirconium phosphate was mixed with BiVO4-δ, ball-milled, and then immersed in sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0012] A2, silicotungstic acid is dispersed in anhydrous ethanol to obtain a silicotungstic acid ethanol solution, chlorinated phosphazene polymer is dispersed in anhydrous ethanol and the silicotungstic acid ethanol solution is added and stirred evenly. After filtration, washing and drying, chlorinated phosphazene polymer composite is obtained.

[0013] A3, aluminum dihydrogen phosphate, basic magnesium carbonate and lithium molybdate are mixed and ball-milled, then ammonium dihydrogen phosphate is added and allowed to stand for aging to obtain a mixture. The mixture is heated to a second temperature and held to obtain a melt. The melt is poured into ice water and the fragments are immersed in ammonia water. The mixture is ball-milled and dried to obtain glass ceramics.

[0014] S1, 4,4'-difluorobenzophenone and 4,4'-biphenylhydroquinone are dispersed in sulfolane and potassium carbonate is added. Under a nitrogen atmosphere, the mixture is heated to a third temperature and reacted. The temperature is then lowered to a fourth temperature and pentafluorophenyltriethoxysilane is added to continue the reaction. The reaction solution is cooled to room temperature and poured into ice water to obtain a precipitate. The precipitate is crushed, washed, and dried to obtain a modified resin. The modified resin is dispersed in N-methylpyrrolidone to obtain a resin solution.

[0015] S2, BiVO4 composite material, chlorinated phosphazene polymer composite, glass ceramic and phosphate coupling agent are dispersed in N-methylpyrrolidone, ultrasonically dispersed and then added to resin solution, and ground by a three-roll mill to obtain a rust-preventive coating composition.

[0016] In high-temperature pipeline environments, the metal substrate is highly susceptible to passivation film rupture and stress corrosion cracking. Bismuth vanadate, after reduction treatment, introduces a high concentration of oxygen vacancy defects. These defects become deep-seated trapping centers for free electrons at high temperatures. When the pipeline metal undergoes anodic dissolution, these oxygen vacancies continuously trap conduction electrons, inhibiting the kinetics of the cathodic oxygen reduction reaction and fundamentally weakening the efficiency of the electrochemical corrosion cell. Zirconium phosphate, with its layered crystal structure, possesses unique asymmetric thermal expansion characteristics. Its interlayer slip capability effectively buffers the shear stress caused by the difference in thermal expansion coefficients between the coating and the carbon steel substrate. This micro / nano-scale adaptive deformation behavior converts macroscopic thermal stress into energy dissipation at the lattice level, significantly reducing the probability of microcrack initiation in the coating during temperature cycling. More importantly, the active phosphate groups enriched on the zirconium phosphate surface migrate directionally to the coating defect area under high temperature, reacting with exposed iron ions to form a dense iron phosphate network structure, instantly sealing the corrosion channel entrance. Simultaneously, vanadium oxides released from the decomposition of bismuth vanadate participate in the construction of a composite passivation layer with a spinel topology. Its three-dimensional ion channels effectively impede oxygen ion diffusion, achieving dynamic self-reinforcement of the passivation film at extreme temperatures. Furthermore, dihydrogen phosphate ions react with hydroxyl groups on the zirconium phosphate surface to form stable covalent bonds, transforming the inert layered material into an active phosphate enrichment platform. Secondly, phosphate groups act as molecular bridges connecting the bismuth vanadate and zirconium phosphate interface, constructing a high-strength heterojunction through double-ended coordination bonds, suppressing high-temperature phase separation. Finally, the surface-immobilized phosphate ions become a self-healing source during pipeline service. When microcracks appear in the coating or the substrate is exposed, the active phosphorus species generated by the pyrolysis of phosphate ions rapidly react with iron ions to form a dense iron phosphate passivation film, instantly sealing the corrosion channel.

[0017] Chlorinated phosphazene polymers are high-molecular-weight compounds containing phosphorus and nitrogen bonds, exhibiting excellent heat resistance and chemical stability in their molecular framework. The polyoxometalate clusters of silicotungstic acid crosslink with the polymer side chains through strong ionic bonds, forming a nanoscale interpenetrating network structure. This effectively prevents microcrack nucleation when localized stress concentration occurs in the pipeline system due to sudden temperature changes or pressure shocks. Silicotungstic acid undergoes progressive hydrolysis in high-temperature and high-humidity environments, releasing tungsten oxide anions that diffuse along the concentration gradient to the damaged area of ​​the coating. These anions then undergo a coordination precipitation reaction with ferrous ions generated from electrochemical dissolution, forming iron tungstate polymers. These precipitates preferentially deposit at the microcrack tips and internal pores, achieving physical sealing of the damaged area through volume expansion. Simultaneously, their semiconductor properties inhibit the development of localized galvanic corrosion. Furthermore, the polymer framework of chlorinated phosphazene polymers effectively buffers thermal stress in the coating system, reducing coating cracking caused by thermal expansion mismatch.

[0018] The penetration and erosion of molten salt media at high temperatures, along with the weakening of the coating / substrate interface, are the main causes of pipeline failure. During the thermal process, the phosphate glass network undergoes controlled phase separation, forming a connected amorphous phase that becomes a high-speed channel for ion migration. Lithium ions, with their smallest ionic radius and highest mobility, preferentially diffuse to the coating surface and combine with corrosive anions in the molten salt to form stable compounds. Simultaneously, molybdate ions construct a negative charge barrier on the metal substrate surface through chemisorption, repelling corrosive media such as chloride ions and establishing a selective penetration barrier within the coating. Rapid cooling of the melt in ice water quickly forms a glassy material. This process inhibits excessive growth of the crystalline phase, resulting in a highly uniform microstructure in the final material. Subsequently, the fragments are immersed in ammonia water for post-treatment. The alkalinity of ammonia water modifies the material surface, giving it better interfacial bonding properties. Ammonia post-treatment not only neutralizes residual acidic components but also forms an ammonium salt buffer layer at the interface. This layer stabilizes the chemical environment of the transition zone through a hydrogen bond network, inhibiting adhesion degradation caused by interfacial hydrolysis.

[0019] Traditional polymers suffer from chain segment dissociation and weakened interfacial bonding at high temperatures, leading to coating failure. The spatial conjugation effect of the biphenyl structure significantly enhances molecular chain rigidity, and the torsional barrier between its two benzene rings effectively hinders chain slip and free radical chain-splitting reactions at high temperatures. The fluorosilane end-capping agent undergoes a stepwise reaction during curing: the siloxane first hydrolyzes to generate highly reactive silanol, which then dehydrates and condenses with hydroxyl groups on the metal surface to form a silicon-oxygen-iron covalent bond; the perfluorophenyl then forms a high-strength electrostatic adsorption layer on the substrate surface through a strong electron-withdrawing effect. This synergistic effect of covalent bonding and physical adsorption enhances the interfacial binding energy, and the ether bonds in the resin molecular chain impart moderate flexibility, allowing for micro-elastic deformation under thermal stress and preventing peeling failure caused by interfacial stress concentration. The final coating system forms a dynamic stress buffer network through interlayer slip of zirconium phosphate and molecular chain movement of phosphazene polymer. Glass ceramic particles act as rigid fillers, blocking the propagation path of microcracks. The compressive stress field generated by the gradient of their thermal expansion coefficients causes the cracks to tend to close. At the moment of microcrack formation, the molten phase on the surface of the glass ceramic particles flows into the crack under capillary action to achieve physical filling. At the same time, the tungsten oxide anions dissociated from silicotungstic acid react with metal ions at the crack tip to form a closed precipitate. The phosphate ions released by zirconium phosphate form a chemical passivation film with the matrix metal. The oxygen vacancies of bismuth vanadate selectively adsorb sulfate ions, the lithium ion traps of glass ceramic capture chloride ions, and the dense aromatic ring structure of biphenyl resin constructs a molecular-level sieving barrier, blocking the diffusion path of small molecule corrosive media to the substrate interface.

[0020] As a preferred embodiment of the present invention, in A1, the mass ratio of bismuth nitrate pentahydrate to ammonium metavanadate is (4.8-5.0):(1.1-1.2), for example, it can be (4.80, 4.82, 4.84, 4.86, 4.88, 4.90, 4.92, 4.94, 4.96, 4.98 or 5.00):(1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.20), but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] In some alternative instances, the mass ratio of bismuth nitrate pentahydrate to nitric acid solution is (4.80, 4.82, 4.84, 4.86, 4.88, 4.90, 4.92, 4.94, 4.96, 4.98, or 5.00):30, for example (4.8-5.0):30, and the concentration of nitric acid solution is 4M, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0022] In some alternative instances, the mass ratio of ammonium metavanadate to sodium hydroxide solution is (1.1-1.2):25, for example, it can be (1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19 or 1.20):25, and the concentration of sodium hydroxide solution is 2M, but is not limited to the values ​​listed, and other unlisted values ​​within this range are also applicable.

[0023] In some alternative examples, the temperature of the hydrothermal reaction is 180-185°C, for example, 180.0°C, 180.5°C, 181.0°C, 181.5°C, 182.0°C, 182.5°C, 183.0°C, 183.5°C, 184.0°C, 184.5°C, or 185.0°C, and the time of the hydrothermal reaction is 12-13 hours, for example, 12.0 hours, 12.1 hours, 12.2 hours, 12.3 hours, 12.4 hours, 12.5 hours, 12.6 hours, 12.7 hours, 12.8 hours, 12.9 hours, or 13.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0024] In some optional examples, the mixed gas is an H2 / Ar mixture with a hydrogen volume fraction of 5% and a total flow rate of 50 mL / min.

[0025] In some alternative instances, the first temperature is 400-420°C, for example, it can be 400°C, 402°C, 404°C, 406°C, 408°C, 410°C, 412°C, 414°C, 416°C, 418°C or 420°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0026] In some optional embodiments, the holding time at the first temperature is 2-3 hours, for example, it can be 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3.0 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] In some optional instances, the mass ratio of the α-zirconium phosphate to BiVO4-δ is 1:1.

[0028] In some optional instances, the concentration of the sodium dihydrogen phosphate solution is 0.1 M.

[0029] As a preferred technical solution of the present invention, in A2, the mass-to-volume ratio of silicotungstic acid to anhydrous ethanol in dispersing silicotungstic acid is (10-10.5) g:50 mL, for example, it can be (10, 10.05, 10.1, 10.15, 10.2, 10.25, 10.3, 10.35, 10.4, 10.45 or 10.5) g:50 mL, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] In some optional examples, the chlorinated phosphazene polymer is dispersed in anhydrous ethanol at a mass-to-volume ratio of chlorinated phosphazene polymer to anhydrous ethanol of 1 g: 10 mL.

[0031] In some alternative instances, the mass ratio of the silicotungstic acid to the chlorophosphazene polymer is (2-2.1):1, for example, it can be (2.00, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09 or 2.10):1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] As a preferred embodiment of the present invention, in A3, the mass ratio of aluminum dihydrogen phosphate, basic magnesium carbonate, lithium molybdate, and ammonium dihydrogen phosphate is (50-55):(30-35):15:(8-10), for example, it can be (50.0, 50.5, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 or 55.0):(30.0, 30.5, 31.0, 31.5, 32.0, 32.5, 33.0, 33.5, 34.0, 34.5 or 35.0):15:(8.0, 8.2, 8.4, 8.6, 8.8, 9.0, 9.2, 9.4, 9.6, 9.8 or 10.0), but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] In some optional instances, the settling time is 12-13 hours, for example, 12.0 hours, 12.1 hours, 12.2 hours, 12.3 hours, 12.4 hours, 12.5 hours, 12.6 hours, 12.7 hours, 12.8 hours, 12.9 hours, or 13.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0034] In some alternative instances, the second temperature is 1300-1320°C, for example, it can be 1300°C, 1302°C, 1304°C, 1306°C, 1308°C, 1310°C, 1312°C, 1314°C, 1316°C, 1318°C or 1320°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0035] In some optional examples, the holding time at the second temperature is 1.5-2.0 h, for example, it can be 1.5 h, 1.55 h, 1.6 h, 1.65 h, 1.7 h, 1.75 h, 1.8 h, 1.85 h, 1.9 h, 1.95 h, or 2.0 h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. In some optional examples, the mass fraction of the ammonia water is 5 wt.%.

[0036] As a preferred embodiment of the present invention, in S1, the mass ratio of 4,4'-difluorobenzophenone, 4,4'-biphenylhydrazine, sulfolane, potassium carbonate, and pentafluorophenyltriethoxysilane is (100-115):(60-65):600:70:5. For example, it can be (100.0, 101.5, 103.0, 104.5, 106.0, 107.5, 109.0, 110.5, 112.0, 113.5, or 115.0):(60.0, 60.5, 61.0, 61.5, 62.0, 62.5, 63.0, 63.5, 64.0, 64.5, or 65.0):600:70:5, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In some alternative instances, the third temperature is 190-195°C, for example, it can be 190.0°C, 190.5°C, 191.0°C, 191.5°C, 192.0°C, 192.5°C, 193.0°C, 193.5°C, 194.0°C, 194.5°C or 195.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0038] In some alternative instances, the reaction time at the third temperature is 3-4 hours, for example, 3.0 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, or 4.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0039] In some alternative instances, the fourth temperature is 150-155°C, for example, it can be 150.0°C, 150.5°C, 151.0°C, 151.5°C, 152.0°C, 152.5°C, 153.0°C, 153.5°C, 154.0°C, 154.5°C, or 155.0°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0040] In some optional instances, the continued reaction time is 2-3 hours, for example, 2.0 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours, or 3.0 hours, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0041] As a preferred embodiment of the present invention, in S2, the mass ratio of the BiVO4 composite material, chlorophosphazene polymer composite, glass ceramic, phosphate coupling agent, N-methylpyrrolidone, and resin solution is (8-10):(5-7):(10-13):1:20:(65-70), for example, it can be (8.0, 8.2, 8.4, 8.6, 8.8, 9.0, 9.2, 9.4, 9.6, 9.8 or 10.0):(5.0, 5.2, 5.4, 5.6, 5. 8, 6.0, 6.2, 6.4, 6.6, 6.8 or 7.0: (10.0, 10.3, 10.6, 10.9, 11.2, 11.5, 11.8, 12.1, 12.4, 12.7 or 13.0): 1:20: (65.0, 65.5, 66.0, 66.5, 67.0, 67.5, 68.0, 68.5, 69.0, 69.5 or 70.0), but not limited to the listed values, other unlisted values ​​within this range also apply.

[0042] In some optional examples, the resin solution has a mass fraction of 40 wt.%.

[0043] In a second aspect, the present invention provides a rust-preventive coating composition prepared by the preparation method described in the first aspect.

[0044] Thirdly, the rust-preventive coating composition provided by the present invention is applied to high-temperature pipelines / pipelines.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Based on the composite of bismuth vanadate with oxygen vacancy and zirconium phosphate, the electrochemical corrosion process is effectively suppressed and the thermal stress impact is buffered. The active phosphate groups fixed on the surface migrate directionally to the damaged area at high temperature and react with the exposed substrate to generate a dense passivation film, realizing the immediate self-sealing of microcracks. The rigid-flexible interpenetrating network formed by phosphazene chloride and silicotungstic acid releases tungsten oxide anions that are deposited at the crack tip to form a chemical sealing layer, giving the coating dynamic self-healing ability; (2) Aluminum magnesium molybdenum phosphate glass ceramics construct ion selective channels through controlled phase separation. Lithium ions and molybdate ions work together to intercept the penetration of corrosive media and strengthen the coating interface bonding. The rigid conjugated skeleton of biphenyl polyarylether ketone resin resists high temperature chain dissociation. Fluorosilane end groups are anchored to the metal substrate through covalent bonds and electrostatic adsorption, achieving excellent protective effect. Detailed Implementation

[0046] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0047] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0048] Example 1

[0049] This embodiment provides a rust-preventive coating composition and its preparation method, the preparation method specifically including the following steps:

[0050] A1. 4.8 g of bismuth nitrate pentahydrate was dispersed in 30 g of 4M nitric acid solution to obtain a bismuth solution. 1.1 g of ammonium metavanadate was dispersed in 25 g of 2M sodium hydroxide solution and added to the bismuth solution. The pH was adjusted to 2.0. The solution was then transferred to a polytetrafluoroethylene-lined reactor for hydrothermal reaction at 180℃ for 12 h. After drying, BiVO4 was obtained. BiVO4 was placed in a tube furnace, and a mixed gas (H2 / Ar mixture with 5% hydrogen by volume and a total flow rate of 50 mL / min) was introduced. The temperature was raised to 400℃ and held for 2 h to obtain BiVO4-δ. 10 g of α-zirconium phosphate was mixed with 10 g of BiVO4-δ, ball-milled, and then immersed in 0.1 M sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0051] A2, 10g of silicotungstic acid was dispersed in 50mL of anhydrous ethanol to obtain a silicotungstic acid ethanol solution, 5g of chlorinated phosphazene polymer was dispersed in 50mL of anhydrous ethanol and the silicotungstic acid ethanol solution was added and stirred evenly. After filtration, washing and drying, the chlorinated phosphazene polymer composite was obtained.

[0052] A3, 50g aluminum dihydrogen phosphate, 30g basic magnesium carbonate and 15g lithium molybdate were mixed and ball-milled, and then 8g ammonium dihydrogen phosphate was added and allowed to stand for 12h to mature to obtain a mixture. The mixture was heated to 1300℃ and kept at that temperature for 1.5h. The melt was poured into ice water and the fragments were immersed in 5wt.% ammonia water. The mixture was ball-milled and dried to obtain glass ceramics.

[0053] S1, 100g of 4,4'-difluorobenzophenone and 60g of 4,4'-biphenylhydroquinone were dispersed in 600g of sulfolane and 70g of potassium carbonate were added. Under a nitrogen atmosphere, the mixture was heated to 190℃ and reacted for 3h. The temperature was then lowered to 150℃ and 5g of pentafluorophenyltriethoxysilane was added to continue the reaction for 2h. The reaction solution was cooled to room temperature and poured into ice water to obtain a precipitate. The precipitate was crushed, washed, and dried to obtain a modified resin. The modified resin was dispersed in N-methylpyrrolidone to obtain a resin solution.

[0054] S2, 8g BiVO4 composite material, 5g chlorinated phosphazene polymer composite, 10g glass ceramic and 1g phosphate coupling agent are dispersed in 20g N-methylpyrrolidone, ultrasonically dispersed and then 65g of 40wt.% resin solution is added. After grinding with a three-roll mill, an anti-rust coating composition is obtained.

[0055] Example 2

[0056] This embodiment provides a rust-preventive coating composition and its preparation method, the preparation method specifically including the following steps:

[0057] A1. 5.0 g of bismuth nitrate pentahydrate was dispersed in 30 g of 4M nitric acid solution to obtain a bismuth solution. 1.15 g of ammonium metavanadate was dispersed in 25 g of 2M sodium hydroxide solution and added to the bismuth solution. The pH was adjusted to 2.2. The solution was then transferred to a polytetrafluoroethylene-lined reactor for hydrothermal reaction at 182℃ for 12.3 h. After drying, BiVO4 was obtained. BiVO4 was placed in a tube furnace, and a mixed gas (H2 / Ar mixture with 5% hydrogen by volume and a total flow rate of 50 mL / min) was introduced. The temperature was raised to 410℃ and held for 3 h to obtain BiVO4-δ. 10 g of α-zirconium phosphate was mixed with 10 g of BiVO4-δ, ball-milled, and then immersed in 0.1 M sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0058] A2, 10.5g of silicotungstic acid was dispersed in 50mL of anhydrous ethanol to obtain a silicotungstic acid ethanol solution, 5g of chlorinated phosphazene polymer was dispersed in 50mL of anhydrous ethanol and the silicotungstic acid ethanol solution was added and stirred evenly. After filtration, washing and drying, the chlorinated phosphazene polymer composite was obtained.

[0059] A3, 55g aluminum dihydrogen phosphate, 35g basic magnesium carbonate and 15g lithium molybdate were mixed and ball-milled, and then 10g ammonium dihydrogen phosphate was added and allowed to stand for 13h to mature to obtain a mixture. The mixture was heated to 1310℃ and kept at that temperature for 2.0h. The melt was poured into ice water and the fragments were immersed in 5wt.% ammonia water. The mixture was ball-milled and dried to obtain glass ceramics.

[0060] S1, 115g of 4,4'-difluorobenzophenone and 65g of 4,4'-biphenylhydroquinone were dispersed in 600g of sulfolane and 70g of potassium carbonate were added. Under a nitrogen atmosphere, the mixture was heated to 192℃ and reacted for 4h. The temperature was then lowered to 152℃ and 5g of pentafluorophenyltriethoxysilane was added to continue the reaction for 3h. The reaction solution was cooled to room temperature and poured into ice water to obtain a precipitate. The precipitate was crushed, washed and dried to obtain a modified resin. The modified resin was dispersed in N-methylpyrrolidone to obtain a resin solution.

[0061] S2, 9g BiVO4 composite material, 7g chlorinated phosphazene polymer composite, 13g glass ceramic and 1g phosphate coupling agent are dispersed in 20g N-methylpyrrolidone, ultrasonically dispersed and then 70g of 40wt.% resin solution is added. After grinding with a three-roll mill, an anti-rust coating composition is obtained.

[0062] Example 3

[0063] This embodiment provides a rust-preventive coating composition and its preparation method, the preparation method specifically including the following steps:

[0064] A1. 4.9 g of bismuth nitrate pentahydrate was dispersed in 30 g of 4M nitric acid solution to obtain a bismuth solution. 1.2 g of ammonium metavanadate was dispersed in 25 g of 2M sodium hydroxide solution and added to the bismuth solution. The pH was adjusted to 2.5. The solution was then transferred to a polytetrafluoroethylene-lined reactor for hydrothermal reaction at 185℃ for 13 h. After drying, BiVO4 was obtained. BiVO4 was placed in a tube furnace, and a mixed gas (H2 / Ar mixture with 5% hydrogen by volume and a total flow rate of 50 mL / min) was introduced. The temperature was raised to 420℃ and held for 2.4 h to obtain BiVO4-δ. 10 g of α-zirconium phosphate was mixed with 10 g of BiVO4-δ, ball-milled, and then immersed in 0.1 M sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0065] A2, 10.2g of silicotungstic acid was dispersed in 50mL of anhydrous ethanol to obtain a silicotungstic acid ethanol solution, 5g of chlorinated phosphazene polymer was dispersed in 50mL of anhydrous ethanol and the silicotungstic acid ethanol solution was added and stirred evenly. After filtration, washing and drying, the chlorinated phosphazene polymer composite was obtained.

[0066] A3, 51g aluminum dihydrogen phosphate, 31g basic magnesium carbonate and 15g lithium molybdate were mixed and ball-milled, and then 9g ammonium dihydrogen phosphate was added and allowed to stand for 12.4h to mature to obtain a mixture. The mixture was heated to 1320℃ and kept at that temperature for 1.7h. The melt was poured into ice water and the fragments were immersed in 5wt.% ammonia water. The mixture was ball-milled and dried to obtain glass ceramics.

[0067] S1, 110g of 4,4'-difluorobenzophenone and 61g of 4,4'-biphenylhydroquinone were dispersed in 600g of sulfolane and 70g of potassium carbonate were added. Under a nitrogen atmosphere, the mixture was heated to 195℃ and reacted for 3.3h. The temperature was then lowered to 155℃ and 5g of pentafluorophenyltriethoxysilane was added, and the reaction was continued for 2.4h. The reaction solution was cooled to room temperature and poured into ice water to obtain a precipitate. The precipitate was crushed, washed, and dried to obtain a modified resin. The modified resin was dispersed in N-methylpyrrolidone to obtain a resin solution.

[0068] S2, 10g BiVO4 composite material, 6g chlorinated phosphazene polymer composite, 12g glass ceramic and 1g phosphate coupling agent are dispersed in 20g N-methylpyrrolidone, ultrasonically dispersed and then 67g of 40wt.% resin solution is added. After grinding with a three-roll mill, a rust-preventive coating composition is obtained.

[0069] Example 4

[0070] This embodiment provides a rust-preventive coating composition and its preparation method, the preparation method specifically including the following steps:

[0071] A1. 5.0 g of bismuth nitrate pentahydrate was dispersed in 30 g of 4M nitric acid solution to obtain a bismuth solution. 1.18 g of ammonium metavanadate was dispersed in 25 g of 2M sodium hydroxide solution and added to the bismuth solution. The pH was adjusted to 2.3. The solution was then transferred to a polytetrafluoroethylene-lined reactor for hydrothermal reaction at 184 °C for 12.7 h. After drying, BiVO4 was obtained. BiVO4 was placed in a tube furnace, and a mixed gas (H2 / Ar mixture with 5% hydrogen by volume and a total flow rate of 50 mL / min) was introduced. The temperature was raised to 415 °C and held for 2.8 h to obtain BiVO4-δ. 10 g of α-zirconium phosphate was mixed with 10 g of BiVO4-δ, ball-milled, and then immersed in 0.1 M sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained.

[0072] A2, 10.4 g of silicotungstic acid was dispersed in 50 mL of anhydrous ethanol to obtain a silicotungstic acid ethanol solution, 5 g of chlorinated phosphazene polymer was dispersed in 50 mL of anhydrous ethanol and the silicotungstic acid ethanol solution was added and stirred evenly. After filtration, washing and drying, the chlorinated phosphazene polymer composite was obtained.

[0073] A3, 54g aluminum dihydrogen phosphate, 33g basic magnesium carbonate and 15g lithium molybdate were mixed and ball-milled, and then 8.5g ammonium dihydrogen phosphate was added and allowed to stand for 12.8h to mature to obtain a mixture. The mixture was heated to 1315℃ and held for 1.9h. The melt was poured into ice water and the fragments were immersed in 5wt.% ammonia water. The mixture was ball-milled and dried to obtain glass ceramics.

[0074] S1, 108g of 4,4'-difluorobenzophenone and 64g of 4,4'-biphenylhydroquinone were dispersed in 600g of sulfolane and 70g of potassium carbonate were added. Under a nitrogen atmosphere, the mixture was heated to 194℃ and reacted for 3.6h. The temperature was then lowered to 154℃ and 5g of pentafluorophenyltriethoxysilane was added, and the reaction was continued for 2.7h. The reaction solution was cooled to room temperature and poured into ice water to obtain a precipitate. The precipitate was crushed, washed, and dried to obtain a modified resin. The modified resin was dispersed in N-methylpyrrolidone to obtain a resin solution.

[0075] S2, 8.5g BiVO4 composite material, 5.5g chlorinated phosphazene polymer composite, 11g glass ceramic and 1g phosphate coupling agent are dispersed in 20g N-methylpyrrolidone, ultrasonically dispersed and then 69g of 40wt.% resin solution is added. After grinding with a three-roll mill, an anti-rust coating composition is obtained.

[0076] Comparative Example 1

[0077] This comparative example provides a rust-preventive coating composition and its preparation method. The difference between this example and Example 1 is that the mass of the BiVO4 composite material in S2 is 0, while the other process parameters and operating conditions are exactly the same as in Example 1.

[0078] Comparative Example 2

[0079] This comparative example provides a rust-preventive coating composition and its preparation method. The difference between this example and Example 1 is that the mass of the chlorinated phosphazene polymer composite in S2 is 0, while the other process parameters and operating conditions are exactly the same as in Example 1.

[0080] Comparative Example 3

[0081] This comparative example provides a rust-preventive coating composition and its preparation method. The difference between this example and Example 1 is that the mass of the glass ceramic in S2 is 0, while the other process parameters and operating conditions are exactly the same as in Example 1.

[0082] High-temperature adhesion test method: The substrate is a low-carbon steel plate (100*100*25mm). After the coating is cured, a high-temperature tensile tester is used to install the sample in the test chamber and heat it to the target temperature (200℃) at a rate of 5℃ / min. The temperature is kept constant for 30 minutes to ensure uniform temperature. A tensile load is applied at a constant rate of 1MPa / s until the coating peels off, and the maximum load value is recorded in real time.

[0083] Thermal shock test method: The sample size is 50*50*3mm, and the edges are chamfered by 0.5mm. It is placed in a muffle furnace preheated to 200℃ and kept at that temperature for 15 minutes. Then it is quickly transferred to a 25℃ deionized water bath (transfer time ≤10 seconds). After soaking for 10 seconds, it is taken out and dried. After each cycle, the coating surface is visually inspected under white light oblique illumination. If continuous linear lines are found, it is considered unqualified. Suspicious areas are re-examined with a 20x handheld microscope to confirm the crack morphology. The cycle is repeated until visible cracks appear or 15 cycles are completed.

[0084] High-temperature oxidation-salt spray coupled test method: Take a 304 stainless steel substrate (100*100*3mm), sandblast it to a surface roughness of Sa2.5, chamfer the edges with a 0.5mm bevel, control the dry film thickness to 50±5μm, and cover the coating edges with high-temperature resistant silicone sealant. The exposed area is 80cm². After drying the sample at 120℃ for 1 hour, record the initial mass m0. Tilt the sample at 15° and fix it on the salt spray chamber sample holder. Maintain the temperature inside the chamber at 35℃±1℃, and spray a 5% mass fraction. A sodium chloride solution (compliant with ASTM B117 standard) was sprayed for 4 hours to ensure a salt deposition of 3.5 ± 0.5 mg / cm² (3 samples were randomly selected from each batch for weighing and verification). After spraying, the samples were transferred to a 60°C forced-air drying oven and allowed to stand for 1 hour to form a uniform salt film. The muffle furnace was then preheated to 200°C ± 10°C. Within 10 seconds of opening the furnace door, the samples were transferred to the center of the furnace and kept at this temperature for 2 hours in air, with temperature fluctuations controlled within ± 5°C. After the holding period, the samples were immediately placed on a forced-air cooling platform. The above salt spray-high-temperature oxidation process was repeated for a total of 20 cycles. The integrity of the sealant was checked, and any damage was immediately repaired. Corrosion weight gain determination: The samples were ultrasonically cleaned with deionized water, dried, and weighed to obtain the final mass m1. The change in mass per unit area was calculated as: Corrosion weight gain = (m1 - m0) / 80. The test was terminated if any of the following conditions occurred: visible coating peeling, or cracks observed penetrating to the substrate interface in the cross-section.

[0085] The test results are shown in Table 1.

[0086] Table 1. Test results of a rust-preventive coating composition from Examples 1-4 and Comparative Examples 1-3.

[0087]

[0088] As shown in Table 1, compared to Example 1, Comparative Example 1 exhibits decreased high-temperature adhesion, reduced thermal shock test performance, and increased corrosion weight gain; Comparative Example 2 also shows decreased high-temperature adhesion, reduced thermal shock test performance, and increased corrosion weight gain; and Comparative Example 3 exhibits decreased high-temperature adhesion, reduced thermal shock test performance, and increased corrosion weight gain. This is because the BiVO4 composite material in Comparative Example 1 has a mass of 0, lacking oxygen vacancy electron traps, leading to accelerated anodic dissolution of the substrate. Simultaneously, the self-healing function fails, and thermal stress cracks cannot be sealed through the iron phosphate passivation film, thus reducing the high-temperature protection effect. In Comparative Example 2, the chlorinated phosphazene polymer composite has a mass of 0, resulting in the disappearance of the stress dissipation network, concentration of thermal expansion stress at the interface, increased coating brittleness, and microcracks becoming corrosion channels, leading to increased corrosion weight gain. In Comparative Example 3, the glass-ceramic has a mass of 0, making it unable to construct a negative charge barrier on the metal substrate surface through chemical adsorption, thus repelling corrosive media such as chloride ions.

[0089] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a rust-preventive coating composition, characterized in that, The preparation method includes: A1. Bismuth nitrate pentahydrate was dispersed in nitric acid solution to obtain bismuth solution. Ammonium metavanadate was dispersed in sodium hydroxide solution and added to bismuth solution for hydrothermal reaction to obtain BiVO4. BiVO4 was placed in a tube furnace and heated by passing a mixed gas to obtain BiVO4-δ. α-Zrconium phosphate was mixed with BiVO4-δ, ball-milled, and then immersed in sodium dihydrogen phosphate solution. After filtration, washing, and drying, BiVO4 composite material was obtained. S1, 4,4'-difluorobenzophenone and 4,4'-biphenylhydroquinone are dispersed in sulfolane and potassium carbonate is added to react. Pentafluorophenyltriethoxysilane is added to continue the reaction to obtain a modified resin. The modified resin is dispersed in N-methylpyrrolidone to obtain a resin solution. S2, BiVO4 composite material, chlorinated phosphazene polymer composite, glass ceramic and phosphate coupling agent are dispersed in N-methylpyrrolidone, ultrasonically dispersed and then added to resin solution to obtain a rust-proof coating composition. The preparation method of the chlorinated phosphazene polymer complex includes: dispersing silicotungstic acid in anhydrous ethanol to obtain a silicotungstic acid ethanol solution, dispersing chlorinated phosphazene polymer in anhydrous ethanol and adding the silicotungstic acid ethanol solution and stirring evenly, filtering, washing and drying to obtain the chlorinated phosphazene polymer complex. The preparation method of the glass ceramic includes: mixing aluminum dihydrogen phosphate, basic magnesium carbonate and lithium molybdate, ball milling, adding ammonium dihydrogen phosphate and allowing it to stand for aging to obtain a mixture, heating the mixture to obtain a melt, pouring the melt into ice water and immersing the fragments in ammonia water, ball milling and drying to obtain the glass ceramic.

2. The method for preparing a rust-preventive coating composition according to claim 1, characterized in that, In A1: The mass ratio of bismuth nitrate pentahydrate to ammonium metavanadate is (4.8-5.0):(1.1-1.2). The mixed gas is an H2 / Ar mixture with a hydrogen volume fraction of 5% and a total flow rate of 50 mL / min. The mass ratio of α-zirconium phosphate to BiVO4-δ is 1:

1.

3. The method for preparing a rust-preventive coating composition according to claim 1, characterized in that, In S1: The mass ratio of 4,4'-difluorobenzophenone, 4,4'-biphenyldiphenol, sulfolane, potassium carbonate and pentafluorophenyltriethoxysilane is (100-115):(60-65):600:70:

5.

4. The method for preparing a rust-preventive coating composition according to claim 1, characterized in that, In S2: The mass ratio of the BiVO4 composite material, chlorinated phosphazene polymer composite, glass ceramic, phosphate coupling agent, N-methylpyrrolidone and resin solution is (8-10):(5-7):(10-13):1:20:(65-70); The resin solution has a mass fraction of 40 wt.%.

5. The method for preparing a rust-preventive coating composition according to claim 1, characterized in that, In the preparation method of the chlorinated phosphazene polymer complex: The mass ratio of silicotungstic acid to chlorinated phosphazene polymer is (2-2.1):

1.

6. The method for preparing a rust-preventive coating composition according to claim 1, characterized in that, In the preparation method of the glass-ceramic: The mass ratio of aluminum dihydrogen phosphate, basic magnesium carbonate, lithium molybdate and ammonium dihydrogen phosphate is (50-55):(30-35):15:(8-10).

7. A rust-preventive coating composition is obtained by the preparation method according to any one of claims 1-6.

8. The application of a rust-preventive coating composition in high-temperature pipelines / pipelines obtained by the preparation method according to any one of claims 1-6.

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