A boron carbide composite ceramic material, a method for preparing the same and applications thereof

Abstract

The application relates to a boron carbide composite ceramic material and a preparation method and application thereof, and the preparation method comprises the following steps: uniformly ball-milling boron oxide powder, carbon powder, deionized water, a dispersing agent, a binder and an oxide sintering aid to obtain slurry; drying, crushing and sieving the slurry to obtain mixed powder; laying the mixed powder on a carbon fiber plate and placing the carbon fiber plate into a graphite mold to perform electric field assisted pressure sintering to obtain a sintered body composite material; bonding the carbon fiber surface of the sintered body composite material to the fiber plate to obtain the boron carbide composite ceramic material; wherein the process of the electric field assisted pressure sintering is as follows: heating to 1600 DEG C to 1800 DEG C, the pressure in the heating stage is 40 MPa to 120 MPa; keeping warm for 60 min to 120 min, the pressure in the keeping warm stage is 90 MPa to 110 MPa; cooling to 200 DEG C to 350 DEG C, the pressure in the cooling stage is 40 MPa to 60 MPa; and cooling to room temperature in the furnace.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and in particular to a boron carbide composite ceramic material, its preparation method, and its application. Background Technology

[0002] With advancements in cutting-edge technologies and the continuous upgrading of high-energy, high-kill weapons, armor protection materials face challenges such as resistance to high-speed projectile fire, resistance to multiple projectile fire, and rapid assembly. Currently, in-service armor protection materials are categorized into metal ballistic materials, ceramic ballistic materials, and high-performance fiber ballistic materials. Among these, boron carbide ceramics, as a typical representative, have become a hot topic in the research and promotion of ballistic materials due to their high strength, high hardness, high elastic modulus, good stability, and lightweight properties.

[0003] Although ceramic materials possess sufficient hardness, their brittleness and low fracture strength prevent them from being used alone as homogeneous armor; a rigid backing plate is essential for support. Fiber-based materials, on the other hand, exhibit high modulus, high toughness, high compressive strength, and high tensile strength, enabling them to resist penetration damage. They are commonly used as backing layers. The two materials are often bonded together using adhesives or mechanical connections to form a ceramic composite material, leveraging the advantages of both and demonstrating excellent ballistic protection. However, this bonding method typically suffers from low bond strength, poor toughness, and delayed stress wave transmission. When impacted by high-speed fragments, the ceramic material can fracture brittlely, penetrating the fiber backing plate and severely impacting the combat effectiveness of the armor protection material.

[0004] Therefore, it is of great significance to find a better way to combine ceramic materials with fiber backing plates to achieve better ballistic performance. Summary of the Invention

[0005] The main objective of this invention is to provide a boron carbide composite ceramic material, its preparation method, and its application. The technical problem to be solved is how to better combine the ceramic material with the fiber backing to give it better ballistic performance and make it more suitable for practical use.

[0006] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for preparing a boron carbide composite ceramic material according to this invention includes the following steps:

[0007] Boron oxide powder, carbon powder, deionized water, dispersant, binder and oxide sintering aid are ball-milled and mixed to obtain a slurry;

[0008] The aforementioned slurry is dried, crushed, and sieved to obtain a mixed powder;

[0009] The aforementioned mixed powder was spread evenly on a carbon fiber plate, placed in a graphite mold, and sintered under pressure with an electric field to obtain a sintered composite material.

[0010] The carbon fiber surface of the aforementioned sintered composite material is bonded to a fiberboard to obtain a boron carbide composite ceramic material.

[0011] The aforementioned electric field-assisted pressure sintering process is as follows:

[0012] The temperature is raised to 1600℃~1800℃, and the pressure during the heating stage is 40MPa~120MPa;

[0013] Keep warm for 60 to 120 minutes, with a pressure of 90 to 110 MPa during the heat preservation stage;

[0014] The temperature is reduced to 200–350℃, and the pressure during the cooling stage is 40 MPa–60 MPa.

[0015] Cool to room temperature with the furnace.

[0016] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0017] Preferably, in the aforementioned method for preparing boron carbide composite ceramic materials, the heating rate is 80–150 °C / min and the cooling rate is 80–100 °C / min.

[0018] Preferably, in the aforementioned method for preparing boron carbide composite ceramic materials, the particle size of the mixed powder is less than 300 mesh; and / or,

[0019] The aforementioned dispersant is at least one selected from tetramethylammonium hydroxide, glyceryl tristearate, sodium hexametaphosphate, polyacrylamide, polyvinylpyrrolidone, sodium lauryl sulfate, sodium carboxymethyl cellulose, phosphate esters, and polyethylene glycol; and / or,

[0020] The aforementioned adhesive is at least one selected from polyvinyl alcohol, polyvinyl butyral, methacrylate, cellulose, polyurethane, polyisobutylene, and water-soluble phenolic resin; and / or,

[0021] The aforementioned sintering aid is at least one of Al2O3, Y2O3, TiO2 and ZrO2.

[0022] Preferably, in the aforementioned method for preparing boron carbide composite ceramic materials, the mass ratio of the boron oxide powder to the aforementioned carbon powder is (2-3):1.

[0023] Preferably, in the aforementioned method for preparing boron carbide composite ceramic material, the sum of the masses of the boron oxide powder and the aforementioned carbon powder is 1, the mass of deionized water is 1 to 5, the mass of the aforementioned dispersant is 0.001 to 0.1, the mass of the aforementioned binder is 0.01 to 0.05, and the mass of the aforementioned sintering aid is 0 to 0.1.

[0024] Preferably, in the aforementioned method for preparing boron carbide composite ceramic materials, the specific method for ball milling and mixing is as follows: ball milling and mixing is performed using a horizontal ball mill at a speed of 50-200 rpm for a duration of 0.5-10 h, with a ball-to-material ratio of (10-1):1.

[0025] Preferably, in the aforementioned method for preparing boron carbide composite ceramic materials, the carbon fiber plate is at least one of polyacrylonitrile-based carbon fiber, viscose-based carbon fiber, pitch-based carbon fiber, lignin-based carbon fiber, and grown carbon fiber; the thickness of the aforementioned carbon fiber plate is 1 to 10 mm.

[0026] The aforementioned fiberboard types are ultra-high molecular weight polyethylene fiber, aramid fiber, Kevlar fiber, and glass fiber; the thickness of the aforementioned fiberboard is 6-7 mm.

[0027] Preferably, in the aforementioned method for preparing boron carbide composite ceramic material, an adhesive is used to bond the carbon fiber surface of the sintered composite material to the fiberboard to obtain the boron carbide composite ceramic material.

[0028] The types of adhesives include epoxy resin adhesives, epoxy ethylene resin adhesives, polyurethane adhesives, and acrylic adhesives; the bonding thickness is 0.2–1 mm.

[0029] The objective of this invention and the technical problem it solves are also achieved by the following technical solution. This invention proposes a boron carbide composite ceramic material, which is prepared by any of the aforementioned methods.

[0030] The objective of this invention and the technical problem it solves are also achieved by the following technical solution. This invention proposes the application of the aforementioned boron carbide composite ceramic material in the field of protection.

[0031] By employing the above technical solution, the boron carbide composite ceramic material, its preparation method, and its application of the present invention have at least the following advantages:

[0032] (1) In conventional armor protection materials, the interfacial bonding between ceramic and fiber backing layer is weak. When subjected to impact from high-speed projectiles, the ceramic will fracture brittlely, causing the fiber backing to be punctured, which seriously affects the combat effectiveness of the armor protection material. The magnitude of the interfacial bonding strength is the key to the performance of composite materials. If the bonding strength is too high, the toughening effect of the fiber cannot be fully utilized; if it is too low, sufficient strength cannot be obtained. To address the above shortcomings, this invention patent uses formula design and electric field-assisted pressure sintering technology to react boron oxide powder and carbon powder during sintering at a certain temperature and pressure. Oriented needle-shaped or rod-shaped boron carbide crystals are grown in the pores of carbon fibers. Then, oxide sintering aids are added to form a glassy phase, which fills the pores to form a dense sintered composite material. A boron carbide / carbon fiber transition layer with strong bonding is formed between the two. The good interfacial bonding can effectively transfer the energy of the projectile to the carbon fiber, dissipating the energy of the projectile through carbon fiber compression, shearing, and stretching, and fully utilizing the excellent ballistic performance of carbon fiber.

[0033] (2) Compared with spark plasma sintering (SPS), electric field assisted pressure sintering has the following advantages: it can quickly achieve densification sintering and high-temperature synthesis through DC current heating and axial pressure. It does not use expensive and difficult-to-control pulse power supplies, is inexpensive, and can form large-sized ceramic materials.

[0034] (3) Electric field-assisted pressure sintering is used to obtain nano- or submicron-sized boron carbide fine grains with a faster heating rate and greater pressure, forming a dense boron carbide ceramic.

[0035] (4) Through electric field-assisted pressure sintering technology, carbon powder and boron oxide powder, under high temperature and high pressure, generate oriented needle-shaped or rod-shaped boron carbide crystals in the pores of carbon fibers. Excess boron oxide powder can also serve as a sintering aid for boron carbide ceramics, filling the pores as a glassy phase. A strong boron carbide ceramic / carbon fiber transition layer is formed between the two, integrating the boron carbide ceramic and carbon fiber plate into a single sintering process, thus solving the problem of poor interfacial bonding between ceramics and carbon fibers. Good interfacial bonding can effectively transfer the energy of the projectile to the carbon fiber, dissipating the energy of the projectile through compression, shearing, and stretching of the carbon fiber, fully utilizing the excellent ballistic performance of the carbon fiber.

[0036] (5) The structure of boron carbide composite ceramic material is boron carbide ceramic as the face plate, boron carbide / carbon fiber transition layer + carbon fiber plate as the middle layer, and fiber plate as flexible back plate. The overall structure changes from hard to soft, which can consume more impact energy.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0038] Figure 1 These are schematic diagrams of the structure of boron carbide composite ceramic materials in some embodiments of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of a rapid hot pressing sintering furnace in some embodiments of the present invention;

[0040] Among them, 1-boron carbide ceramic; 2-boron carbide / carbon fiber transition layer; 3-carbon fiber plate; 4-fiber plate. Detailed Implementation

[0041] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed description of the boron carbide composite ceramic material, its preparation method, and its application, including its specific implementation methods, structure, features, and effects. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0042] This invention proposes a method for preparing boron carbide composite ceramic materials, such as... Figure 1-2 As shown, it includes the following steps:

[0043] Boron oxide powder, carbon powder, deionized water, dispersant, binder and oxide sintering aid are ball-milled and mixed to obtain a slurry;

[0044] The aforementioned slurry is dried, crushed, and sieved to obtain a mixed powder;

[0045] The aforementioned mixed powder was spread evenly on carbon fiber plate 3, placed in a graphite mold, and sintered under pressure with electric field assistance to obtain a sintered composite material.

[0046] The carbon fiber surface of the aforementioned sintered composite material is bonded to fiberboard 4 to obtain boron carbide composite ceramic material.

[0047] The aforementioned electric field-assisted pressure sintering process is as follows:

[0048] The temperature is raised to 1600℃~1800℃, and the pressure during the heating stage is 40MPa~120MPa;

[0049] Keep warm for 60 to 120 minutes, with a pressure of 90 to 110 MPa during the heat preservation stage;

[0050] The temperature is reduced to 200–350℃, and the pressure during the cooling stage is 40 MPa–60 MPa.

[0051] Cool to room temperature with the furnace.

[0052] Specifically, since the reaction between boron oxide powder and carbon powder to form boron carbide requires extremely high reaction temperatures, but excessively high temperatures can lead to abnormal grain growth, an electric field-assisted pressure sintering method is used to simultaneously apply heat and pressure. The synergistic effect of pressure and electric field facilitates the contact and diffusion of powder particles, lowers the sintering temperature, shortens the sintering time, and promotes the formation of boron carbide ceramic 1. Higher pressure requires lower temperatures and results in better densification. For example, as... Figure 2 As shown, this process can be achieved using a rapid hot pressing sintering furnace, which uses direct current to heat the sintering material and applies pressure to the material through a graphite pressure head and a graphite punch. The sintering process takes place in a vacuum chamber.

[0053] During the heating stage: Direct current passes through the graphite mold and the powder itself, generating Joule heating, which significantly increases the heating rate. The carbon powder and boron oxide powder can quickly reach the sintering temperature and react, preventing abnormal grain growth under prolonged high temperatures. Applying pressure of 40MPa–120MPa helps promote particle rearrangement and break up agglomerates in the early stages of sintering. When the temperature rises to around 450℃, the boron oxide powder melts, forming a glassy liquid, which facilitates mixing with the carbon powder. Furthermore, at 1000℃–1800℃, the oxide sintering aid forms a liquid phase, promoting the densification process.

[0054] During the heat preservation stage, the heat preservation time is 60 min to 120 min, while applying a pressure of 90 MPa to 110 MPa to inhibit grain growth and obtain highly dense, micro-nano-scale boron carbide crystals. At the same time, the boron carbide crystals growing in the pores of the carbon fiber are oriented to form needle-like or rod-like structures.

[0055] During the cooling stage, applying a pressure of 40MPa to 60MPa gradually shapes needle-like or rod-like boron carbide crystals within the pores of the carbon fibers, maintaining the orientation of the crystal structure. The two are then bonded together by a molten sintering agent, forming a strong boron carbide / carbon fiber transition layer 2, thus integrating the boron carbide / carbon fiber into a single sintering process.

[0056] This invention patent utilizes formulation design and electric field-assisted pressure sintering technology to react boron oxide powder and carbon powder during sintering at a specific temperature and pressure. Oriented needle-like or rod-shaped boron carbide crystals grow within the pores of the carbon fibers. Then, oxide sintering aids are added to form a glassy phase, filling the pores and creating a dense sintered composite material. A strong boron carbide / carbon fiber transition layer 2 is formed between the two, and this excellent interfacial bonding effectively transfers the projectile's energy to the carbon fibers. The energy of the projectile is dissipated through compression, shearing, and stretching of the carbon fibers, fully utilizing the excellent ballistic properties of the carbon fibers.

[0057] The boron carbide composite ceramic material provided by the present invention has a boron carbide ceramic 1 as the face plate, a boron carbide / carbon fiber transition layer 2 + carbon fiber plate 3 as the middle layer, and a fiber plate 4 as the flexible back plate. The overall structure changes from hard to soft, which can consume more impact energy.

[0058] Preferably, the heating rate is 80–150 °C / min and the cooling rate is 80–100 °C / min. These preferred heating and cooling rates at this stage can form a good sintering neck, which is beneficial for densification sintering, prevents grain coarsening, facilitates the safe removal of the binder, greatly reduces the risk of ceramic cracking and deformation, and improves production efficiency.

[0059] Preferably, the particle size of the aforementioned mixed powder is less than 300 mesh; and / or, a small particle size of the mixed powder is beneficial for producing high-density ceramics.

[0060] The aforementioned dispersant is at least one selected from tetramethylammonium hydroxide, glyceryl tristearate, sodium hexametaphosphate, polyacrylamide, polyvinylpyrrolidone, sodium lauryl sulfate, sodium carboxymethyl cellulose, phosphate esters, and polyethylene glycol; and / or,

[0061] The aforementioned adhesive is at least one selected from polyvinyl alcohol, polyvinyl butyral, methacrylate, cellulose, polyurethane, polyisobutylene, and water-soluble phenolic resin; and / or,

[0062] The aforementioned sintering aid is at least one of Al2O3, Y2O3, TiO2 and ZrO2.

[0063] Preferably, the mass ratio of the aforementioned boron oxide powder to the aforementioned carbon powder is (2-3):1. The mass ratio of the reactant boron oxide to carbon powder is approximately 1.66:1. In actual reaction, to ensure complete reaction of the carbon powder, the mass of boron oxide is slightly in excess. During sintering, above 1300℃, boron oxide will significantly volatilize, resulting in boron loss. Therefore, excess boron oxide can function as both a reactant and a sintering aid.

[0064] Preferably, the sum of the masses of the aforementioned boron oxide powder and the aforementioned carbon powder is 1, the mass of deionized water is 1 to 5, the mass of the aforementioned dispersant is 0.001 to 0.1, the mass of the aforementioned binder is 0.01 to 0.05, and the mass of the aforementioned sintering aid is 0 to 0.1.

[0065] Preferably, the specific method for ball milling and mixing described above is as follows: ball milling and mixing is performed using a horizontal ball mill at a speed of 50–200 rpm for a duration of 0.5–10 h, with a ball-to-material ratio of (10–1):1. If the speed is too low or the time is too short, the mixing will be uneven; if the speed is too high or the time is too long, impurities from ball milling will be introduced into the slurry, affecting the purity of the slurry.

[0066] Preferably, the aforementioned carbon fiber plate 3 is at least one of polyacrylonitrile-based carbon fiber, viscose-based carbon fiber, pitch-based carbon fiber, lignin-based carbon fiber, and grown carbon fiber; the thickness of the aforementioned carbon fiber plate 3 is 1 to 10 mm.

[0067] The aforementioned fiberboard 4 is made of ultra-high molecular weight polyethylene fiber, aramid fiber, Kevlar fiber, or glass fiber; the thickness of the aforementioned fiberboard 4 is 6-7 mm.

[0068] Preferably, an adhesive is used to bond the carbon fiber surface of the sintered composite material to the fiberboard 4 to obtain a boron carbide composite ceramic material.

[0069] The types of adhesives include epoxy resin adhesives, epoxy ethylene resin adhesives, polyurethane adhesives, and acrylic adhesives; the bonding thickness is 0.2–1 mm.

[0070] This invention proposes a boron carbide composite ceramic material, which is prepared by any of the aforementioned methods.

[0071] This invention proposes the application of the aforementioned boron carbide composite ceramic material in the field of protection.

[0072] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0073] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0074] Example 1

[0075] This embodiment provides a boron carbide composite ceramic material, its preparation method, and its applications. Figure 1-2 As shown.

[0076] 100g of boron oxide powder (0.5μm particle size, 99.9% purity), 50g of carbon powder, 500ml of deionized water, 10g of a mixture of cellulose and tristearate as a dispersant, 2g of polyvinyl butyral as a binder, and 0.25g of Al2O3 as a sintering aid were weighed out. These materials were then ball-milled uniformly using a horizontal ball mill at 50rpm for 10 hours. The ball mill jar was made of zirconium oxide, and the ball-to-powder ratio was 2.5:1.

[0077] The slurry is placed in an oven and dried at 100°C, then crushed and passed through a 300-mesh sieve to obtain a mixed powder.

[0078] The mixed powder was spread evenly on a 150×150×8mm thick polyacrylonitrile-based carbon fiber plate 3, and then placed into a graphite mold in a rapid hot-pressing sintering furnace for electric field-assisted pressure sintering. The heating stage was as follows: heating rate 80℃ / min, pressure 40MPa, temperature increased to 1600℃; holding stage: pressure 90MPa, holding time 60min; cooling stage: cooling rate 80℃ / min, pressure 40MPa, cooling to 200℃; finally, the pressure was reduced to 0, and the furnace was cooled to room temperature, yielding the sintered composite material. The Vickers hardness of the sintered composite material was tested to be 39.7GPa, and the fracture toughness was 4.86MPa·m. 1 / 2 It has a flexural strength of 448 MPa, an average grain size of 420 nm, and a minimum grain size of only 100 nm.

[0079] Using epoxy resin adhesive as a bonding agent, the sintered composite material was bonded to a 150×150×6mm UHMWPE plate with an adhesive thickness of 0.2mm, resulting in a boron carbide composite ceramic material. The areal density of the boron carbide composite ceramic material was measured to be 10.5 kg / m³. 2 In the ballistic performance target test, a 12.7mm armor-piercing incendiary projectile was fired at an initial velocity of 800m / s at a distance of 30m, with a remaining velocity of 704m / s and a back convexity of 26mm.

[0080] First, the temperature is raised to 1600℃~1800℃, with a pressure of 40MPa~120MPa during the heating stage; then it is held for 60min~120min, with a pressure of 90MPa~110MPa during the holding stage; then it is cooled to 200℃, with a pressure of 40MPa~60MPa during the cooling stage; finally, the pressure is reduced to 0, and the furnace is cooled to room temperature.

[0081] Example 2

[0082] This embodiment provides a boron carbide composite ceramic material, its preparation method, and its applications. Figure 1-2 As shown.

[0083] 100g of boron oxide powder (0.3μm particle size, 99.6% purity), 35g of carbon powder, 200ml of deionized water, 5g of a mixture of sodium dodecyl sulfate and sodium carboxymethyl cellulose dispersant, 6g of a mixture of polyvinyl alcohol and methacrylate binder, and 1g of ZrO2 sintering aid were weighed out. These materials were then ball-milled uniformly using a horizontal ball mill at 300rpm for 5 hours. The ball mill jar was made of zirconium oxide, and the ball-to-powder ratio was 10:1.

[0084] The slurry is placed in an oven and dried at 100°C, then crushed and passed through a 300-mesh sieve to obtain a mixed powder.

[0085] The mixed powder was spread evenly on a 150×150×5mm thick viscose-based carbon fiber plate 3, and then placed into a graphite mold in a rapid hot-pressing sintering furnace for electric field-assisted pressure sintering. The heating stage was as follows: heating rate 150℃ / min, pressure 120MPa, temperature increased to 1800℃; holding stage: pressure 110MPa, holding time 120min; cooling stage: cooling rate 100℃ / min, pressure 60MPa, cooling to 200℃; finally, the pressure was reduced to 0, and the furnace was cooled to room temperature to obtain the sintered composite material. The Vickers hardness of the sintered composite material was tested to be 38.4 GPa, and the fracture toughness was 4.39 MPa·m. 1 / 2 It has a bending strength of 395 MPa, an average grain size of 370 nm, and a minimum grain size of only 120 nm.

[0086] Using an epoxy resin adhesive as a binder, the sintered composite material was bonded to a 150×150×7mm glass fiber board 4 with a bonding thickness of 1mm, resulting in a boron carbide composite ceramic material. The areal density of the boron carbide composite ceramic material was measured to be 11.8 kg / m³. 2 In the ballistic performance target test, a 12.7mm armor-piercing incendiary projectile was fired at an initial velocity of 800m / s at a distance of 30m, with a remaining velocity of 743m / s and a back convexity of 30mm.

[0087] Example 3

[0088] This embodiment provides a boron carbide composite ceramic material, its preparation method, and its applications, such as... Figure 1-2 As shown.

[0089] 200g of boron oxide powder (0.2μm particle size, 99.8% purity), 68g of carbon powder, 1000ml of deionized water, 0.3g of sodium dodecyl sulfate dispersant, 13g of polyurethane binder, and 2g of TiO2 sintering aid were weighed out. These materials were then ball-milled uniformly using a horizontal ball mill to obtain a slurry. The horizontal ball mill was operated at 100rpm for 8 hours. The milling jar was made of zirconium oxide, and the ball-to-powder ratio was 1:1.

[0090] The slurry is placed in an oven and dried at 100°C, then crushed and passed through a 300-mesh sieve to obtain a mixed powder.

[0091] The mixed powder was spread evenly on a 150×150×6mm thick pitch-based carbon fiber plate 3, and then placed into a graphite mold in a rapid hot-pressing sintering furnace for electric field-assisted pressure sintering. The heating stage was as follows: heating rate 120℃ / min, pressure 100MPa, temperature increased to 1700℃; holding stage: pressure 100MPa, holding time 90min; cooling stage: cooling rate 90℃ / min, pressure 55MPa, cooling to 200℃; finally, the pressure was reduced to 0, and the furnace was cooled to room temperature, yielding the sintered composite material. The Vickers hardness of the sintered composite material was tested to be 38.4 GPa, and the fracture toughness was 5.14 MPa·m. 1 / 2 It has a flexural strength of 466 MPa, an average grain size of 350 nm, and a minimum grain size of only 150 nm.

[0092] Using acrylic adhesive as a bonding agent, a sintered composite material was bonded to a 150×150×6.5mm UHMWPE plate with a bonding thickness of 0.8mm to prepare a boron carbide composite ceramic material. The areal density of the boron carbide composite ceramic material was measured to be 12.3 kg / m³. 2 In the ballistic performance target test, a 12.7mm armor-piercing incendiary projectile was fired at an initial velocity of 800m / s at a distance of 30m, with a remaining velocity of 685m / s and a back convexity of 35mm.

[0093] Comparative Example 1

[0094] 200g of boron oxide powder (0.2μm particle size, 99.8% purity), 68g of carbon powder, 1000ml of deionized water, 0.3g of sodium dodecyl sulfate dispersant, 13g of polyurethane binder, and 2g of graphene sintering aid were weighed out. The above materials were ball-milled and mixed evenly using a horizontal ball mill at 100rpm for 8 hours. The ball mill jar was made of zirconium oxide, and the ball-to-powder ratio was 1:1. The slurry was then dried, crushed, and passed through a 300-mesh sieve to obtain a mixed powder.

[0095] The mixed powder was loaded into a graphite mold in a rapid hot-pressing sintering furnace and subjected to electric field-assisted pressure sintering. The heating stage involved a heating rate of 120℃ / min and a pressure of 100MPa; the holding stage involved raising the temperature to 1700℃, maintaining the pressure at 100MPa, and holding for 90min; the cooling stage involved a cooling rate of 90℃ / min and a pressure of 55MPa, cooling to 200℃, and finally reducing the pressure to 0, followed by furnace cooling to room temperature. This yielded a boron carbide ceramic panel with dimensions of 150×150×6mm. Testing showed that the boron carbide ceramic panel had a Vickers hardness of 32.6 GPa and a fracture toughness of 3.51 MPa·m. 1 / 2 It has a flexural strength of 350 MPa, an average grain size of 480 nm, and a minimum grain size of 250 nm.

[0096] Using polyurethane as an adhesive, a boron carbide ceramic panel is bonded to a 150×150×6mm pitch-based carbon fiber plate 3, and then the aforementioned pitch-based carbon fiber plate 3 and a 150×150×7mm Kevlar fiber plate 4 are bonded together with a bonding thickness of 0.5mm to obtain a boron carbide composite ceramic material.

[0097] The areal density of the boron carbide composite ceramic material was tested to be 13.6 kg / m³. 2 A 12.7mm armor-piercing incendiary projectile was fired at a speed of 800m / s and a distance of 30m to conduct a ballistic performance test. The initial projectile velocity was 800m / s, the remaining projectile velocity was 789m / s, and the back convexity was 50mm.

[0098] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a boron carbide composite ceramic material, characterized in that, It includes the following steps: Boron oxide powder, carbon powder, deionized water, dispersant, binder and oxide sintering aid are ball-milled and mixed to obtain a slurry; The slurry is dried, crushed, and sieved to obtain a mixed powder. The mixed powder is spread evenly on a carbon fiber plate, placed in a graphite mold, and sintered under pressure with electric field assistance to obtain a sintered composite material. The carbon fiber surface of the sintered composite material is bonded to the fiberboard to obtain a boron carbide composite ceramic material. The electric field-assisted pressure sintering process is as follows: The temperature is raised to 1600℃~1800℃, and the pressure during the heating stage is 40MPa~120MPa; Keep warm for 60-120 minutes, with a pressure of 90-110 MPa during the heat preservation stage; The temperature is reduced to 200~350℃, and the pressure during the cooling stage is 40MPa~60MPa; Cool to room temperature with the furnace.

2. The preparation method according to claim 1, characterized in that, The heating rate is 80~150℃ / min, and the cooling rate is 80~100℃ / min.

3. The preparation method according to claim 1, characterized in that, The particle size of the mixed powder is less than 300 mesh; and / or, The dispersant is at least one selected from tetramethylammonium hydroxide, glyceryl tristearate, sodium hexametaphosphate, polyacrylamide, polyvinylpyrrolidone, sodium lauryl sulfate, sodium carboxymethyl cellulose, phosphate esters, and polyethylene glycol; and / or, The adhesive is at least one selected from polyvinyl alcohol, polyvinyl butyral, methacrylate, cellulose, polyurethane, polyisobutylene, and water-soluble phenolic resin; and / or, The sintering aid is at least one of Al2O3, Y2O3, TiO2 and ZrO2.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the boron oxide powder to the carbon powder is (2~3):

1.

5. The preparation method according to claim 1, characterized in that, The sum of the masses of the boron oxide powder and the carbon powder is 1, the mass of the deionized water is 1 to 5, the mass of the dispersant is 0.001 to 0.1, the mass of the binder is 0.01 to 0.05, and the mass of the sintering aid is 0 to 0.

1.

6. The preparation method according to claim 1, characterized in that, The specific method for ball milling and mixing is as follows: ball milling and mixing is carried out using a horizontal ball mill at a speed of 50~200 rpm for a duration of 0.5h~10h, with a ball-to-material ratio of (10~1):

1.

7. The preparation method according to claim 1, characterized in that, The carbon fiber plate is at least one of polyacrylonitrile-based carbon fiber, viscose-based carbon fiber, pitch-based carbon fiber, lignin-based carbon fiber, and grown carbon fiber; the thickness of the carbon fiber plate is 1~10mm. The fiberboard is made of ultra-high molecular weight polyethylene fiber, aramid fiber, Kevlar fiber, or glass fiber; the thickness of the fiberboard is 6-7 mm.

8. The preparation method according to claim 1, characterized in that, Boron carbide composite ceramic material is obtained by bonding the carbon fiber surface of the sintered composite material to the fiberboard using an adhesive. The adhesives are epoxy resin adhesives, epoxy ethylene resin adhesives, polyurethane adhesives, or acrylic adhesives; the bonding thickness is 0.2~1mm.

9. A boron carbide composite ceramic material, prepared by the method described in any one of claims 1-8.

10. The application of the boron carbide composite ceramic material according to claim 9 in the field of protection.

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