Basalt fiber composite anchor chain and method of making same

Abstract

The present application relates to the technical field of anchor chain, and provides basalt fiber composite anchor chain and a preparation method thereof.The chain link of the anchor chain is made of basalt fiber reinforced composite material, the fiber volume fraction is 50%-70%, the chain link is dumbbell-shaped, a reinforcing member is arranged in the transition area, and the surface is provided with a protective coating.During preparation, the basalt fiber is pretreated, the base resin is accurately prepared, winding forming, special connection mode and other processes are adopted, and post-treatment is strengthened.The performance of the anchor chain is improved through plasma modification and variable-angle winding technology.The tensile strength of the obtained anchor chain is 800-1200 MPa (which is better than 1100 MPa of the traditional R6-grade anchor chain), the strength retention rate is greater than or equal to 95% after being soaked in 3.5% NaCl solution for 12 months, compared with the traditional anchor chain, the anchor chain has the advantages of lightweight, high strength, corrosion resistance and the like, can meet the demand of ocean engineering on high-performance anchor chain, and reduces the use and maintenance cost.

Description

Technical Field

[0001] The present invention relates to the technical field of anchor chains, in particular to a basalt fiber composite anchor chain and a preparation method thereof. Background Art

[0002] As a key component connecting ships and the bottom of the water, anchor chains play a vital role in marine operations. Although traditional metal anchor chains have high strength, they have disadvantages such as heavy weight and easy corrosion. As marine development advances into the deep sea, higher requirements are placed on the lightweight, high strength and corrosion resistance of anchor chains. In the existing technology, some anchor chains made of fiber materials, such as polyester fiber anchor chains, have achieved lightweight to a certain extent, but their strength and fatigue resistance still need to be improved, and it is difficult to meet the needs of long-term, high-intensity operations in complex marine environments. Therefore, the research and development of a new type of anchor chain with excellent comprehensive performance is of great practical significance. Summary of the Invention

[0003] The object of the present invention is to provide a basalt fiber composite anchor chain and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a basalt fiber composite anchor chain, comprising a plurality of chain links, each of which is made of a basalt fiber reinforced composite material; the basalt fiber reinforced composite material comprises basalt fiber and a matrix resin, and the volume fraction of the basalt fiber is 50%-70%; the chain link has a dumbbell-shaped structure, with connecting parts with larger diameters at both ends and a force-bearing part with smaller diameters in the middle, the connecting part being provided with a connecting hole for connecting with adjacent chain links; a reinforcement is provided in the transition region between the connecting part and the force-bearing part, wherein the reinforcement increases the number of winding layers of basalt fiber in the transition region; the surface of the chain link is coated with a layer of protective coating material, the protective coating material being composed of a corrosion-resistant resin and a nano-anti-wear material, the nano-anti-wear material being uniformly dispersed in the corrosion-resistant resin, and the mass fraction of the nano-anti-wear material being 5%-15%.

[0005] Preferably, the reinforcement is locally reinforced in the transition area using high-strength basalt fiber braid.

[0006] Preferably, the matrix resin consists of epoxy resin, curing agent and diluent, and the mass ratio of the epoxy resin, curing agent and diluent is 100:(20-30):(5-10).

[0007] Preferably, the thickness of the protective coating is 0.2-0.5 mm.

[0008] Preferably, a method for preparing a basalt fiber composite anchor chain comprises the following steps:

[0009] Basalt fiber pretreatment: Heat treat the basalt fiber in a high-temperature furnace at 190-210°C for 1-2 hours. Then, immerse the heat-treated basalt fiber in a mixture of ethanol and deionized water in a volume ratio of 1:1 and ultrasonically clean it for 15-30 minutes to remove impurities and moisture from the surface of the basalt fiber. Then, immerse the heat-treated basalt fiber in a silane coupling agent solution with a mass fraction of 2% for 1-2 hours. After removal, dry it at 80-100°C to form a coupling agent film on the surface of the basalt fiber.

[0010] Preparation of base resin: Weigh epoxy resin, curing agent and diluent according to the mass ratio, mix the epoxy resin and diluent evenly, stir at 50-60°C for 30-40 minutes, then add curing agent and continue stirring for 15-20 minutes to obtain base resin;

[0011] Chain link molding: Chain links are prepared using a winding molding process. The pretreated basalt fiber is immersed in the matrix resin through a dipping device to ensure that the fiber is fully impregnated. The dipped fiber is then wound around the chain link mold according to the designed winding path. During the winding process, the fiber tension is controlled at 100-150N. For the reinforcements in the transition area between the connection and the load-bearing part of the chain link, high-strength basalt fiber braids are laid in the corresponding positions by hand, and then the fiber winding is continued. After winding is completed, the mold is placed in a curing oven and cured at 80-120℃ for 3-5 hours, then heated to 150-180℃ and cured for 1-2 hours.

[0012] Chain link connection processing: Remove the solidified chain link from the mold and polish and clean the connection part of the chain link; connect the connection holes of adjacent chain links through connecting pins made of high-strength alloy steel, and apply a layer of grease on the mating surface of the connecting pin and the connecting hole;

[0013] Protective coating coating: Corrosion-resistant resin and nano-anti-wear material are mixed in proportion and evenly dispersed under high-speed stirring to obtain a protective coating material; the epoxy resin base, protective coating material and fluorocarbon resin are sprayed evenly on the surface of the chain link in sequence using a spraying process to form a protective coating, wherein the spraying thickness is controlled at 0.2-0.5mm; after the spraying is completed, the chain link is dried at 60-80℃ for 2-3 hours to solidify the protective coating;

[0014] Chain link connection: connect the chain links coated with protective coating, specifically place several chain links end to end, and fix the connection holes of different chain links with connecting pins to form a basalt fiber composite anchor chain;

[0015] Post-treatment strengthening process: The connected basalt fiber composite anchor chain is placed in an autoclave and treated at a pressure of 0.5-1MPa and a temperature of 80-100°C for 2-4 hours. Then, a cyclic loading pre-stretching treatment is performed, with the loading stress being 30%-50% of the ultimate strength and the number of cycles being 1000-3000, to finally obtain the finished basalt fiber composite anchor chain.

[0016] Preferably, in the basalt fiber pretreatment step, a plasma-magnetron sputtering synergistic modification process is used to replace part of the silane coupling agent treatment, specifically comprising:

[0017] Low-temperature plasma activation: The heat-treated basalt fiber is placed in a plasma treatment device and a mixture of argon and oxygen is introduced. The volume ratio of argon to oxygen is 3:1 to 5:1. The treatment is carried out at a power of 50-100W for 1-3 minutes to generate polar groups on the fiber surface and form a nano-scale rough structure.

[0018] Magnetron sputtering aluminum film: The activated fiber is immediately transferred to the magnetron sputtering equipment and the vacuum degree is 1×10-3~5×10-3P a Under these conditions, a high-purity aluminum target is used for evaporation, with a sputtering power of 80-120W and a deposition temperature of 50-80°C, to form a nano-aluminum film layer with a thickness of 50-100nm. At the same time, the fiber substrate is grounded to promote the uniform deposition of aluminum particles through the electrostatic adsorption effect and eliminate the charge accumulation generated during the sputtering process, ensuring that the density of the nano-aluminum film layer is ≥95%.

[0019] Synergistic modification with silane coupling agent: Immerse the fiber with vapor-deposited aluminum film in a silane coupling agent solution with a mass fraction of 1%-1.5% and soak it at 40-60°C for 30-60 minutes. The silane molecules are combined with the aluminum film layer through Al-O-Si chemical bonds. At the same time, the hydroxyl groups react with the polar groups on the fiber surface to form a three-layer interface transition structure of plasma etching layer-nanoaluminum film-silane coupling agent, that is, a coupling agent film is formed on the surface of the basalt fiber.

[0020] Preferably, the link forming step adopts a variable angle spiral winding process, specifically comprising:

[0021] The winding angle of ±(45-60)° is adopted at the load-bearing part of the chain link to form the main load-bearing layer;

[0022] Use a winding angle of ±(15-30)° at the connection to improve the axial strength of the connection area;

[0023] A gradual winding angle is adopted in the transition area to smoothly transition from the angle of the stress-bearing part to the angle of the connecting part, forming a continuous stress transfer path.

[0024] Preferably, the protective coating coating step adopts a gradient coating structure, specifically comprising:

[0025] First, the surface of the chain link is sprayed with an epoxy resin base to form a bottom layer of epoxy resin base layer with a thickness of 0.05-0.1mm for enhancing the bonding force with the base;

[0026] Then, the epoxy resin base layer is sprayed with a protective coating material to form an intermediate layer of nano wear-resistant material dispersion layer, wherein the mass fraction of the nano wear-resistant material is 10%-15% and the thickness is 0.1-0.3mm;

[0027] Finally, the surface of the nano wear-resistant material dispersion layer is sprayed with fluorocarbon resin to form a surface layer with a thickness of 0.05-0.1mm, providing ultra-low surface energy and self-cleaning function.

[0028] Preferably, in the chain link connecting step, the connecting pin shaft and the connecting hole are connected by interference fit and adhesive composite connection, specifically comprising: the outer diameter of the connecting pin shaft is 0.05-0.1mm larger than the inner diameter of the connecting hole; a layer of epoxy resin adhesive is coated on the surface of the connecting pin shaft; the connecting pin shaft is heated to 100-120℃ and then quickly inserted into the connecting hole by hot mounting process, and after cooling, the interference fit is formed; the adhesive is cured to form a composite connection structure of mechanical locking and chemical bonding.

[0029] Compared with the prior art, the beneficial effects of the present application are: lightweight and high strength: basalt fiber composite anchor chain is based on basalt fiber reinforced composite material, and the volume fraction of basalt fiber is 50%-70%, so that the weight of the anchor chain is reduced by 30%-50% compared with the traditional metal anchor chain, effectively reducing the load of the ship and improving the maneuverability and fuel efficiency of the ship. At the same time, the obtained anchor chain has a tensile strength of 800-1200MPa (better than the 1100MPa of the traditional R6 grade anchor chain), which can withstand greater tension and provide reliable anchoring protection for the ship in marine operations, ensuring the safety of the ship in complex sea conditions.

[0030] Excellent corrosion resistance: the protective coating on the surface of the anchor chain is composed of corrosion-resistant resin and nano wear-resistant material, and the nano wear-resistant material is uniformly dispersed therein with a mass fraction of 5%-15%. This coating design makes the anchor chain have strong corrosion resistance, and after being immersed in 3.5% NaCl solution for 12 months, the strength retention rate is ≥95%, which significantly prolongs the service life of the anchor chain in harsh marine environments, reduces the replacement frequency and reduces the maintenance cost.

[0031] Excellent fatigue resistance: Reinforcements in the transition area between the connection and the load-bearing part, whether increasing the number of basalt fiber winding layers or using high-strength braided fabric for local reinforcement, effectively reduce stress concentration. Combined with a variable-angle spiral winding process, the stress distribution in each link is optimized, significantly improving the fatigue resistance of the anchor chain. It can operate stably under alternating loads such as long-term wave impact and ship sway, and is less prone to fatigue fracture.

[0032] Fiber pretreatment is highly effective: high-temperature heat treatment combined with silane coupling agent treatment removes impurities and moisture from the basalt fiber surface, enhancing the interfacial bonding between the fiber and the matrix resin. Plasma surface modification, replacing part of the silane coupling agent treatment, further introduces polar groups onto the fiber surface, forming a microscopic roughness. This synergistic effect with the silane coupling agent strengthens the bond between the fiber and the resin, thereby enhancing the overall performance of the composite anchor chain.

[0033] Precise and reliable forming and connection processes: The winding process, combined with precise fiber tension control (100-150N) and variable-angle spiral winding, ensures uniformity and stability of the chain link structure, enabling each part of the anchor chain to better withstand loads from different directions. The interference fit and adhesive composite connection between the connecting pin and the connecting hole enhances the connection strength between the links, improving the overall reliability of the anchor chain and reducing the risk of loosening and breakage at the joints.

[0034] The coating and post-treatment processes are refined: The protective coating features a gradient coating structure, with a base layer enhancing adhesion to the substrate, a middle layer providing wear resistance, and a surface layer imparting ultra-low surface energy and self-cleaning properties, providing comprehensive protection for the anchor chain. The post-treatment enhancements, including autoclave treatment and cyclic loading pre-stretching, eliminate internal defects, improve the density and structural stability of the anchor chain, and further enhance its mechanical properties and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the anchor chain structure of the present invention;

[0036] Figure 2 The figure is a schematic flow chart of the preparation method of the basalt fiber composite anchor chain of the present invention.

[0037] In the figure: 1. stress-bearing part; 2. reinforcement member; 3. connection part; 4. connection hole. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0040] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0041] See also Figure 1-2 The present invention provides a technical solution: a basalt fiber composite anchor chain, comprising a plurality of chain links, each chain link being made of a basalt fiber reinforced composite material; the basalt fiber reinforced composite material comprises basalt fiber and a matrix resin, with the volume fraction of the basalt fiber being 50%-70%; the chain link has a dumbbell-shaped structure, with a connecting portion 3 with a larger diameter at both ends and a force-bearing portion 1 with a smaller diameter in the middle, the connecting portion 3 being provided with a connecting hole 4 for connecting with adjacent chain links; a reinforcement 2 is provided in the transition region between the connecting portion 3 and the force-bearing portion 1, wherein the reinforcement 2 increases the number of winding layers of basalt fiber in the transition region; a layer of protective coating material is coated on the surface of the chain link, the protective coating material being composed of a corrosion-resistant resin and a nano-anti-wear material, the nano-anti-wear material being uniformly dispersed in the corrosion-resistant resin, and the mass fraction of the nano-anti-wear material being 5%-15%.

[0042] Furthermore, the reinforcement is locally reinforced in the transition area using high-strength basalt fiber braids.

[0043] Furthermore, the matrix resin is composed of epoxy resin, curing agent and diluent, and the mass ratio of the epoxy resin, curing agent and diluent is 100:(20-30):(5-10).

[0044] Furthermore, the thickness of the protective coating is 0.2-0.5 mm.

[0045] Furthermore, a method for preparing a basalt fiber composite anchor chain comprises the following steps:

[0046] Basalt fiber pretreatment: Heat treat the basalt fiber in a high-temperature furnace at 190-210°C for 1-2 hours. Then, immerse the heat-treated basalt fiber in a mixture of ethanol and deionized water in a volume ratio of 1:1 and ultrasonically clean it for 15-30 minutes to remove impurities and moisture from the surface of the basalt fiber. Then, immerse the heat-treated basalt fiber in a silane coupling agent solution with a mass fraction of 2% for 1-2 hours. After removal, dry it at 80-100°C to form a coupling agent film on the surface of the basalt fiber.

[0047] Preparation of base resin: Weigh epoxy resin, curing agent and diluent according to the mass ratio, mix the epoxy resin and diluent evenly, stir at 50-60°C for 30-40 minutes, then add curing agent and continue stirring for 15-20 minutes to obtain base resin;

[0048] Chain link molding: Chain links are prepared using a winding molding process. The pretreated basalt fiber is immersed in the matrix resin through a dipping device to ensure that the fiber is fully impregnated. The dipped fiber is then wound around the chain link mold according to the designed winding path. During the winding process, the fiber tension is controlled at 100-150N. For the reinforcements in the transition area between the connection and the load-bearing part of the chain link, high-strength basalt fiber braids are laid in the corresponding positions by hand, and then the fiber winding is continued. After winding is completed, the mold is placed in a curing oven and cured at 80-120℃ for 3-5 hours, then heated to 150-180℃ and cured for 1-2 hours.

[0049] Chain link connection processing: Remove the solidified chain link from the mold and polish and clean the connection part of the chain link; connect the connection holes of adjacent chain links through connecting pins made of high-strength alloy steel, and apply a layer of grease on the mating surface of the connecting pin and the connecting hole;

[0050] Protective coating coating: Corrosion-resistant resin and nano-anti-wear material are mixed in proportion and evenly dispersed under high-speed stirring to obtain a protective coating material; the epoxy resin base, protective coating material and fluorocarbon resin are sprayed evenly on the surface of the chain link in sequence using a spraying process to form a protective coating, wherein the spraying thickness is controlled at 0.2-0.5mm; after the spraying is completed, the chain link is dried at 60-80℃ for 2-3 hours to solidify the protective coating;

[0051] Chain link connection: connect the chain links coated with protective coating, specifically place several chain links end to end, and fix the connection holes 4 of different chain links through connecting pins to form a basalt fiber composite anchor chain;

[0052] Post-treatment strengthening process: The connected basalt fiber composite anchor chain is placed in an autoclave and treated at a pressure of 0.5-1MPa and a temperature of 80-100°C for 2-4 hours. Then, a cyclic loading pre-stretching treatment is performed, with the loading stress being 30%-50% of the ultimate strength and the number of cycles being 1000-3000, to finally obtain the finished basalt fiber composite anchor chain.

[0053] Furthermore, in the basalt fiber pretreatment step, a plasma-magnetron sputtering synergistic modification process is used to replace part of the silane coupling agent treatment, specifically including:

[0054] Low-temperature plasma activation: The heat-treated basalt fiber is placed in a plasma treatment device and a mixture of argon and oxygen is introduced. The volume ratio of argon to oxygen is 3:1 to 5:1. The treatment is carried out at a power of 50-100W for 1-3 minutes to generate polar groups on the fiber surface and form a nano-scale rough structure.

[0055] Magnetron sputtering aluminum film: The activated fiber is immediately transferred to the magnetron sputtering equipment and the vacuum degree is 1×10-3~5×10-3P a Under these conditions, a high-purity aluminum target is used for vapor deposition, with a controlled sputtering power of 80-120W and a deposition temperature of 50-80°C, to form a nano-aluminum film layer with a thickness of 50-100nm. Simultaneously, the fiber substrate is grounded to promote uniform deposition of aluminum particles through the electrostatic adsorption effect and eliminate charge accumulation generated during the sputtering process, ensuring that the density of the nano-aluminum film layer is ≥95%. The grounding treatment eliminates the electrostatic field on the fiber surface during magnetron sputtering, preventing the agglomeration of nano-aluminum particles due to charge repulsion, thereby improving the uniformity of the film layer. The conductive aluminum film and the grounding process form an electrostatic shielding effect, reducing electrochemical corrosion of the fiber by stray currents in the marine environment.

[0056] Synergistic modification with silane coupling agent: The fiber with vapor-deposited aluminum film is immersed in a silane coupling agent solution with a mass fraction of 1%-1.5% and soaked at 40-60°C for 30-60 minutes. The silane molecules are bonded to the aluminum film layer through Al-O-Si chemical bonds. At the same time, the hydroxyl groups react with the polar groups on the fiber surface to form a three-layer interface transition structure of plasma etching layer-nanoaluminum film-silane coupling agent. Specifically, the nanoaluminum film (50-100nm) serves as the intermediate transition layer. Its surface oxide film (Al2O3) forms a chemical covalent bond with the silane coupling agent and undergoes a cross-linking reaction with the epoxy groups in the resin matrix, forming a coupling agent film on the surface of the basalt fiber.

[0057] Furthermore, the link forming step adopts a variable angle spiral winding process, specifically including:

[0058] The winding angle of ±(45-60)° is adopted at the load-bearing part 1 of the chain link to form the main load-bearing layer;

[0059] A winding angle of ±(15-30)° is used at the connection part 3 to improve the axial strength of the connection area;

[0060] A gradual winding angle is adopted in the transition area, which smoothly transitions from the angle of the stress-bearing part 1 to the angle of the connecting part 3, forming a continuous stress transfer path.

[0061] Furthermore, the protective coating application step adopts a gradient coating structure, specifically including:

[0062] First, the surface of the chain link is sprayed with epoxy resin to form a bottom epoxy resin base layer with a thickness of 0.05-0.1mm to enhance the bonding strength with the substrate;

[0063] Then, the epoxy resin base layer is sprayed with a protective coating material to form a nano-anti-wear material dispersion layer in the middle layer, wherein the mass fraction of the nano-anti-wear material is 10%-15% and the thickness is 0.1-0.3 mm;

[0064] Finally, the surface of the nano anti-wear material dispersion layer is sprayed with fluorocarbon resin to form a surface layer with a thickness of 0.05-0.1mm, providing ultra-low surface energy and self-cleaning function.

[0065] Furthermore, in the chain link connection step, an interference fit and bonding composite connection method is adopted between the connecting pin and the connecting hole, specifically including: the outer diameter of the connecting pin is 0.05-0.1mm larger than the inner diameter of the connecting hole 4; a layer of epoxy resin adhesive is coated on the surface of the connecting pin; the connecting pin is heated to 100-120°C by a hot-fitting process and then quickly inserted into the connecting hole, and an interference fit is formed after cooling; after the adhesive is cured, a composite connection structure of mechanical locking and chemical bonding is formed.

[0066] The following is an explanation using a specific example: Basalt fiber pretreatment: Select basalt fiber with a specification of 1200tex, place it in a high-temperature furnace, and heat treat it at 200°C for 2 hours. Then immerse the heat-treated basalt fiber in a mixture of ethanol and deionized water with a volume ratio of 1:1, and ultrasonically clean it for 30 minutes to remove impurities and moisture on the surface of the basalt fiber. Then, place the heat-treated basalt fiber in a plasma treatment device, introduce a mixture of argon and oxygen (volume ratio 5:1), and treat it at a power of 100W for 3 minutes to generate polar groups (-OH, -COOH) on the fiber surface and form a nano-scale rough structure (roughness Ra 1.0μm);

[0067] The activated fibers were immediately transferred to a magnetron sputtering device and heated to a vacuum of 3×10-3P. a Under these conditions, a high-purity aluminum target (purity ≥ 99.99%) was used for evaporation, with a controlled sputtering power of 100W and a deposition temperature of 80°C, to form an 80nm thick nano-aluminum film layer. Simultaneously, the fiber substrate was grounded (grounding resistance 0.5Ω) to promote uniform deposition of aluminum particles through electrostatic adsorption and eliminate charge accumulation generated during the sputtering process, ensuring a film density ≥ 95%.

[0068] The fiber with vapor-deposited aluminum film is immersed in a 1.2% KH-560 solution at 50°C for 45 minutes, so that the silane molecules are combined with the aluminum film layer through Al-O-Si chemical bonds. At the same time, the hydroxyl groups react with the polar groups on the fiber surface to form a three-layer interface transition structure of plasma etching layer-nano-aluminum film-silane coupling agent, that is, a coupling agent film is formed on the surface of the basalt fiber.

[0069] Preparation of the base resin: Weigh the epoxy resin, curing agent, and diluent in a mass ratio of 100:20:5. Stir the epoxy resin and diluent at 50°C for 40 minutes to mix thoroughly. Then add the curing agent and continue stirring for 20 minutes to prepare the base resin.

[0070] Chain link molding: Using a winding process, the pretreated basalt fiber is fully impregnated with matrix resin using a resin impregnation device. The impregnated fiber is wrapped around the chain link mold at a tension of 120N. In the transition area between the link connection (3) and the load-bearing portion (1), a high-strength basalt fiber braid is manually laid, followed by fiber winding. After winding, the mold is placed in a curing oven, initially curing at 80°C for 5 hours, then increasing the temperature to 150°C for 2 hours.

[0071] Chain link connection: Remove the solidified chain link from the mold and carefully polish and clean the connection part 3. Select a connecting pin made of high-strength alloy steel, apply grease to the mating surface between it and the connecting hole 4, and connect the connecting holes 4 of adjacent chain links through the connecting pin.

[0072] Protective Coating: A corrosion-resistant resin and nano-antiwear material are mixed in appropriate proportions and stirred at high speed to create the protective coating. Using a spraying process, the epoxy resin base, protective coating material, and fluorocarbon resin are sequentially sprayed onto the chain link surface, with a thickness of 0.2 mm. After spraying, the chain link is dried at 60°C for 3 hours to allow the protective coating to cure.

[0073] Specifically, epoxy resin was selected as the corrosion-resistant resin, and nano-silicon carbide was used as the nano-antiwear material. The nano-antiwear material was prepared at a mass fraction of 5%. Specifically, 95g of the corrosion-resistant resin and 5g of nano-silicon carbide were weighed. The mixture was then stirred in a high-speed blender at 3000 rpm for 30 minutes to uniformly disperse the nano-antiwear material in the corrosion-resistant resin, thereby obtaining a protective coating material.

[0074] Post-treatment strengthening process: The connected basalt fiber composite anchor chain is placed in an autoclave and treated at 0.5 MPa pressure and 80°C for 4 hours. It is then subjected to cyclic loading and pre-stretching treatment at a stress of 30% of the ultimate strength for 1,000 cycles to obtain the finished anchor chain.

[0075] Performance testing of the finished anchor chain revealed a tensile strength of 1200 MPa and an elastic modulus of 80 GPa. After immersion in a 3.5% NaCl solution for 12 months, the strength retention rate was 95%. The static immersion test (simulating a seawater environment) was conducted in accordance with GB / T 10125, "Artificial Atmosphere Corrosion Test - Salt Spray Test," to ensure compliance with national standards.

[0076] The present invention discloses a basalt fiber composite anchor chain and a preparation method thereof. The anchor chain is composed of a plurality of chain links, each of which has a dumbbell-shaped structure and is made of a basalt fiber-reinforced composite material, wherein the volume fraction of the basalt fiber is 50%-70%. A reinforcement is provided in the transition area between the connection part and the load-bearing part, which can be locally reinforced by increasing the number of fiber winding layers or using a high-strength braid. The protective coating on the surface of the chain link is composed of a corrosion-resistant resin and a nano-anti-wear material with a mass fraction of 5%-15%. The preparation method includes basalt fiber pretreatment, matrix resin preparation, chain link molding, chain link connection, protective coating application and post-processing strengthening process. The preparation method adopts plasma synergistic modification, variable angle spiral winding, gradient coating application and composite connection technologies. The obtained anchor chain has a tensile strength of 800-1200 MPa and an elastic modulus of 80-120 GPa. After immersion in a 3.5% NaCl solution for 12 months, the strength retention rate is ≥95%. It has the advantages of lightweight, high strength, corrosion resistance and fatigue resistance, and meets the requirements of marine engineering for high-performance anchor chains.

[0077] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A basalt fiber composite anchor chain comprising a plurality of chain links, characterized in that: Each of the chain links is made of a basalt fiber reinforced composite material; the basalt fiber reinforced composite material includes basalt fiber and matrix resin, and the volume fraction of the basalt fiber is 50%-70%; the structure of the chain link is dumbbell-shaped, with connecting parts (3) with larger diameters at both ends and a force-bearing part (1) with smaller diameters in the middle, and the connecting part (3) is provided with a connecting hole (4) for connecting with adjacent chain links; a reinforcement (2) is provided in the transition area between the connecting part (3) and the force-bearing part (1), wherein the reinforcement (2) increases the number of winding layers of basalt fiber in the transition area; the surface of the chain link is coated with a layer of protective coating material, and the protective coating material is composed of corrosion-resistant resin and nano-anti-wear material, and the nano-anti-wear material is uniformly dispersed in the corrosion-resistant resin, and the mass fraction of the nano-anti-wear material is 5%-15%.

2. The basalt fiber composite anchor chain according to claim 1, characterized in that: The reinforcement (2) is locally reinforced in the transition area using high-strength basalt fiber braid.

3. The basalt fiber composite anchor chain according to claim 1, characterized in that: The matrix resin consists of epoxy resin, curing agent and diluent, and the mass ratio of the epoxy resin, curing agent and diluent is 100:(20-30):(5-10).

4. The basalt fiber composite anchor chain according to claim 1, characterized in that: The thickness of the protective coating is 0.2-0.5 mm.

5. The method for preparing a basalt fiber composite anchor chain according to any one of claims 1 to 4, characterized in that: The following steps are involved: Basalt fiber pretreatment: Heat treat the basalt fiber in a high-temperature furnace at 190-210°C for 1-2 hours. Then, immerse the heat-treated basalt fiber in a mixture of ethanol and deionized water in a volume ratio of 1:1 and ultrasonically clean it for 15-30 minutes to remove impurities and moisture from the surface of the basalt fiber. Then, immerse the heat-treated basalt fiber in a silane coupling agent solution with a mass fraction of 2% for 1-2 hours. After removal, dry it at 80-100°C to form a coupling agent film on the surface of the basalt fiber. Preparation of base resin: Weigh epoxy resin, curing agent and diluent according to the mass ratio, mix the epoxy resin and diluent evenly, stir at 50-60°C for 30-40 minutes, then add curing agent and continue stirring for 15-20 minutes to obtain base resin; Chain link molding: Chain links are prepared using a winding molding process. The pretreated basalt fiber is immersed in the matrix resin through a dipping device to ensure that the fiber is fully impregnated. The dipped fiber is then wound around the chain link mold according to the designed winding path. During the winding process, the fiber tension is controlled at 100-150N. For the reinforcements in the transition area between the connection and the load-bearing part of the chain link, high-strength basalt fiber braids are laid in the corresponding positions by hand, and then the fiber winding is continued. After winding is completed, place the mold in a curing oven and cure at 80-120°C for 3-5 hours, then heat to 150-180°C and cure for 1-2 hours; Chain link connection processing: Remove the solidified chain link from the mold and polish and clean the connection part of the chain link; connect the connection holes of adjacent chain links through connecting pins made of high-strength alloy steel, and apply a layer of grease on the mating surface of the connecting pin and the connecting hole; Protective coating coating: Corrosion-resistant resin and nano-anti-wear material are mixed in proportion and evenly dispersed under high-speed stirring to obtain a protective coating material; the epoxy resin base, protective coating material and fluorocarbon resin are sprayed evenly on the surface of the chain link in sequence using a spraying process to form a protective coating, wherein the spraying thickness is controlled at 0.2-0.5mm; after the spraying is completed, the chain link is dried at 60-80℃ for 2-3 hours to solidify the protective coating; Anchor chain assembly: connecting the chain links coated with the protective coating, specifically placing a number of chain links end to end, and fixing the connection holes (4) of different chain links together through connecting pins to form a basalt fiber composite anchor chain; Post-treatment strengthening process: The connected basalt fiber composite anchor chain is placed in an autoclave and treated at a pressure of 0.5-1MPa and a temperature of 80-100°C for 2-4 hours. Then, a cyclic loading pre-stretching treatment is performed, with the loading stress being 30%-50% of the ultimate strength and the number of cycles being 1000-3000, to finally obtain the finished basalt fiber composite anchor chain.

6. The method for preparing a basalt fiber composite anchor chain according to claim 5, characterized in that: In the basalt fiber pretreatment step, a plasma-magnetron sputtering synergistic modification process is used to replace part of the silane coupling agent treatment, specifically including: Low-temperature plasma activation: The heat-treated basalt fiber is placed in a plasma treatment device and a mixture of argon and oxygen is introduced. The volume ratio of argon to oxygen is 3:1 to 5:

1. The treatment is carried out at a power of 50-100W for 1-3 minutes to generate polar groups on the fiber surface and form a nano-scale rough structure. Magnetron sputtering aluminum film: The activated fiber is immediately transferred to the magnetron sputtering equipment and the vacuum degree is 1×10-3~5×10-3P a Under these conditions, a high-purity aluminum target is used for evaporation, with a sputtering power of 80-120W and a deposition temperature of 50-80°C, to form a nano-aluminum film layer with a thickness of 50-100nm. At the same time, the fiber substrate is grounded to promote the uniform deposition of aluminum particles through the electrostatic adsorption effect and eliminate the charge accumulation generated during the sputtering process, ensuring that the density of the nano-aluminum film layer is ≥95%. Synergistic modification with silane coupling agent: Immerse the fiber with vapor-deposited aluminum film in a silane coupling agent solution with a mass fraction of 1%-1.5% and soak it at 40-60°C for 30-60 minutes to form a three-layer interface transition structure of plasma etching layer-nanoaluminum film-silane coupling agent, that is, a coupling agent film is formed on the surface of the basalt fiber.

7. The method for preparing a basalt fiber composite anchor chain according to claim 5, characterized in that: The chain link forming step adopts a variable angle spiral winding process, specifically including: A winding angle of ±(45-60)° is adopted at the load-bearing portion (1) of the chain link to form a main load-bearing layer; A winding angle of ±(15-30)° is adopted at the connection portion (3) to improve the axial strength of the connection area; A gradual winding angle is adopted in the transition area to smoothly transition from the angle of the stress-bearing portion (1) to the angle of the connecting portion (3), thereby forming a continuous stress transfer path.

8. The method for preparing a basalt fiber composite anchor chain according to claim 5, characterized in that: The protective coating coating step adopts a gradient coating structure, specifically comprising: First, the surface of the chain link is sprayed with epoxy resin to form a bottom epoxy resin base layer with a thickness of 0.05-0.1mm to enhance the bonding strength with the substrate; Then, the epoxy resin base layer is sprayed with a protective coating material to form a nano-anti-wear material dispersion layer in the middle layer, wherein the mass fraction of the nano-anti-wear material is 10%-15% and the thickness is 0.1-0.3 mm; Finally, the surface of the nano anti-wear material dispersion layer is sprayed with fluorocarbon resin to form a surface layer with a thickness of 0.05-0.1mm, providing ultra-low surface energy and self-cleaning function.

9. The method for preparing a basalt fiber composite anchor chain according to claim 5, characterized in that: In the chain link connection step, the connecting pin and the connecting hole are connected by an interference fit and bonding composite connection method, specifically including: the outer diameter of the connecting pin is 0.05-0.1 mm larger than the inner diameter of the connecting hole (4); a layer of epoxy resin adhesive is coated on the surface of the connecting pin; the connecting pin is heated to 100-120° C. by a hot-installation process and then quickly inserted into the connecting hole, and an interference fit is formed after cooling; and after the adhesive is cured, a composite connection structure of mechanical locking and chemical bonding is formed.

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