Composite bulletproof material and preparation method thereof as well as composite bulletproof sheet and application thereof

Abstract

The invention provides a composite bulletproof material and a preparation method thereof as well as a composite bulletproof sheet and application thereof, the composite bulletproof material comprises a recrystallized silicon carbide matrix and a composite material which is filled in internal pores of the recrystallized silicon carbide matrix and covers the surface of the recrystallized silicon carbide matrix, the composite material comprises cured resin and silicon carbide particles. According to the composite bulletproof material provided by the invention, the surface of the recrystallized silicon carbide matrix is covered with the composite material, and the internal pores of the recrystallized silicon carbide matrix are filled with the composite material, so that the porosity of the composite bulletproof material is reduced, and the bending resistance, fracture toughness and corrosion resistance of the composite bulletproof material are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bulletproofing, and relates to a composite bulletproof material, in particular to a composite bulletproof material and a preparation method thereof, a composite bulletproof sheet and applications thereof. Background Art

[0002] The development of bulletproof materials has always revolved around the three core requirements of "lightweight, high protection, and environmental adaptability." Traditional metal armor (such as steel plates) is gradually being replaced by high-performance ceramics and fiber composites due to their high density and susceptibility to corrosion. Silicon carbide (SiC) ceramics, with their high hardness, low density, and excellent thermal stability, have become the mainstream choice for bulletproof ceramics.

[0003] However, ordinary SiC ceramics have the problems of high brittleness and poor fracture toughness, which limits their application in individual protective equipment. Recrystallized silicon carbide (R-SiC) optimizes the grain boundary structure through a high-temperature sintering process, significantly improving the fracture toughness of the material. Studies have shown that the fracture toughness of R-SiC is more than 30% higher than that of traditional reaction-sintered silicon carbide. However, due to residual volatiles and uneven sintering shrinkage during the preparation process, R-SiC still has the defect of high porosity, which makes it difficult for its corrosion resistance and anti-ballistic properties to meet the needs of complex battlefield environments.

[0004] In the existing technology, epoxy resin (such as E44 epoxy resin) is used to fill the pores of R-SiC. Although it can partially block the corrosive medium, the bonding strength between the resin and the ceramic interface is weak, and the resin cannot compensate for the brittleness of the ceramic. As a result, the bending resistance and fracture toughness of the composite material filled with epoxy resin R-SiC pores are still limited.

[0005] CN111348920A discloses a titanium diboride / silicon carbide composite bulletproof material, its preparation method, and its application. The material is composed of the following raw materials in percentage by weight: 20-80 wt% titanium diboride powder, 20-80 wt% silicon carbide powder, 0.5-15 wt% carbon powder, 0.5-35 wt% silicon powder, 0.5-3.0 wt% dispersant, and 1-10 wt% binder, with the total percentage by weight of each component being 100 wt%. By introducing silicon as a liquid phase, this invention reduces the sintering temperature and promotes the migration and transport of substances in the liquid phase, thereby increasing density and improving density uniformity. However, the bending resistance and fracture toughness of this titanium diboride / silicon carbide composite bulletproof material still cannot meet the requirements of practical applications.

[0006] CN119263844A discloses a method for preparing recrystallized silicon carbide products. This method employs a one-step molding process, resulting in a green body that does not require sintering. Instead, a thermosetting binder is cured through a gradient temperature ramp, dramatically increasing the green body's strength to form a matrix. An impregnation formula and process are then designed based on the matrix's structure. Multiple impregnations allow finer particles to fully fill the matrix's pores. After sintering, even finer pores are formed, reducing porosity. The resulting silicon carbide component has a porosity of 3.0 g / cm. However, the bending resistance and fracture toughness of this recrystallized silicon carbide product do not meet the requirements of practical applications.

[0007] Composite bulletproof materials disclosed in the prior art all have certain drawbacks, including poor porosity, bending resistance, fracture toughness, and corrosion resistance, which fail to meet the requirements of practical applications. Therefore, the development and design of new composite bulletproof materials, their preparation methods, composite bulletproof sheets, and their applications are of vital importance. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the object of the present invention is to provide a composite bullet-proof material and a preparation method thereof, a composite bullet-proof sheet and an application thereof. In the composite bullet-proof material provided by the present invention, by covering the surface of a recrystallized silicon carbide matrix with a composite material and filling the internal pores of the recrystallized silicon carbide matrix with the composite material, not only the porosity of the composite bullet-proof material is reduced, but also the bending resistance, fracture toughness and corrosion resistance of the composite bullet-proof material are improved.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a composite bullet-proof material, comprising a recrystallized silicon carbide matrix, and a composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix;

[0011] The composite material includes cured resin and silicon carbide particles.

[0012] The composite bullet-proof material provided by the present invention comprises a composite material, wherein silicon carbide particles in the composite material are uniformly dispersed in an epoxy resin, forming a dual interface bond of mechanical interlocking and chemical bonding, thereby enhancing the shear strength of the interface between the silicon carbide particles and the epoxy resin, and endowing the composite material with excellent flexural strength and fracture toughness. Therefore, the composite material disposed on the surface and in the internal pores of the recrystallized silicon carbide matrix can compensate for the brittleness of the recrystallized silicon carbide matrix, thereby enhancing the flexural resistance and fracture toughness of the composite bullet-proof material. In addition, because the composite material composed of the cured resin and the silicon carbide particles has good corrosion resistance, after the composite material is filled in the internal pores of the recrystallized silicon carbide matrix, it can not only reduce the porosity of the composite bullet-proof material, but also block the penetration of corrosive media into the pores of the recrystallized silicon carbide matrix. Moreover, after the composite material covers the surface of the recrystallized silicon carbide matrix, it can to a certain extent block direct contact between the recrystallized silicon carbide matrix and the corrosive medium, thereby enhancing the corrosion resistance of the composite bullet-proof material.

[0013] In summary, in the composite bullet-proof material provided by the present invention, by covering the surface of the recrystallized silicon carbide matrix with a composite material and filling the internal pores of the recrystallized silicon carbide matrix with the composite material, not only the porosity of the composite bullet-proof material is reduced, but also the bending resistance, fracture toughness and corrosion resistance of the composite bullet-proof material are improved.

[0014] Preferably, the porosity of the recrystallized silicon carbide matrix is ​​≤5%, for example, it can be 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5% or 5.0%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0015] Preferably, based on the total mass of the composite material, the mass fraction of silicon carbide particles in the composite material is 20wt% to 40wt%, for example, it can be 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt% or 40wt%, but it is not limited to the listed values. Other unlisted values ​​within this numerical range are also applicable, and the balance is cured resin.

[0016] Preferably, the silicon carbide particles in the composite material include silicon carbide particles modified with a silane coupling agent.

[0017] Preferably, the average particle size of the silicon carbide particles in the composite material is 10 nm to 100 nm, for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0018] Preferably, the curable resin comprises a curable epoxy resin.

[0019] Preferably, the cured epoxy resin comprises cured bisphenol A epoxy resin.

[0020] Preferably, the cured bisphenol A epoxy resin includes cured E44 epoxy resin and / or cured E51 epoxy resin.

[0021] Preferably, the composite bulletproof material further comprises a self-repairing coating, wherein the self-repairing coating contains self-repairing microcapsules;

[0022] The recrystallized silicon carbide matrix and the composite material form a core, and the self-repairing coating is coated on the surface of the core.

[0023] In the present invention, when the composite bullet-proof material is impacted by external force, microcracks will be generated. When the microcracks expand, the self-repairing microcapsules in the self-repairing coating of the composite bullet-proof material will release prepolymers, increasing the self-repair rate, thereby significantly improving the mechanical properties of the composite bullet-proof material and extending the service life of the composite bullet-proof material.

[0024] The composite bullet-proof material provided by the present invention adopts a densified recrystallized silicon carbide matrix, fills the pores of the recrystallized silicon carbide matrix with a composite material, and then coats the surface of the inner core formed by the recrystallized silicon carbide matrix and the composite material with a self-repairing coating containing self-repairing microcapsules. Under the synergistic effect, the density, bending resistance and fracture toughness of the composite bullet-proof material are effectively improved, and the self-repair rate is significantly increased.

[0025] Preferably, the thickness of the self-healing coating is 50 μm to 200 μm, for example, it can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm or 200 μm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0026] Preferably, the microcapsule wall material of the self-repairing microcapsules in the self-repairing coating includes polyurea formaldehyde and / or gelatin-gum arabic composite, and the microcapsule core material includes silicone prepolymer.

[0027] Preferably, the siloxane prepolymer includes any one or a combination of at least two of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) or dodecamethylcyclohexasiloxane (D6). Typical but non-limiting combinations include a combination of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, a combination of decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane, or a combination of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane.

[0028] Preferably, the mass ratio of the microcapsule wall material to the microcapsule core material in the self-healing coating is (1 to 2.2):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2.0:1 or 2.2:1, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0029] In a second aspect, the present invention provides a method for preparing the composite bullet-proof material according to the first aspect, the method comprising:

[0030] (1) performing a first sintering on a mixture of two silicon carbide particles having different particle sizes to obtain a matrix skeleton; then mixing a silicon carbide slurry with the obtained matrix skeleton and performing a second sintering to obtain a recrystallized silicon carbide matrix;

[0031] (2) Mixing the recrystallized silicon carbide matrix obtained in step (1) with the silicon carbide particle resin slurry, and then curing the mixture to obtain the composite bulletproof material.

[0032] In step (1) of the preparation method of the present invention, a mixture of two silicon carbide particles with different particle sizes is first sintered and then mixed with silicon carbide slurry and sintered, thereby significantly reducing the porosity of the prepared recrystallized silicon carbide matrix and increasing the density of the recrystallized silicon carbide matrix, thereby facilitating the improvement of the impact resistance of the prepared composite bullet-proof material.

[0033] In step (2) of the preparation method of the present invention, the recrystallized silicon carbide matrix is ​​mixed with the silicon carbide particle resin slurry and then solidified. This not only achieves filling of the composite material in the pores of the recrystallized silicon carbide matrix, thereby enhancing the interface bonding force between the recrystallized silicon carbide matrix and the composite material and improving the corrosion resistance of the composite bullet-proof material, but also covers the recrystallized silicon carbide matrix with the composite material, thereby further improving the corrosion resistance of the composite bullet-proof material.

[0034] The preparation method provided by the present invention also has the advantages of simple manufacturing process, low requirements on the environment, and low requirements on production equipment, and is suitable for popularization and use.

[0035] Preferably, the mixture in step (1) comprises first silicon carbide particles having an average particle size of 20 μm to 100 μm, and second silicon carbide particles having an average particle size of 0.5 μm to 1 μm.

[0036] In the present invention, the mixture in step (1) includes first silicon carbide particles having an average particle size of 20 μm to 100 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In the present invention, the mixture in step (1) includes second silicon carbide particles having an average particle size of 0.5 μm to 1 μm, for example, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1.0 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, in the mixture, the mass ratio of the first silicon carbide particles to the second silicon carbide particles is (1.5-2.4):1, for example, it can be 1.5:1, 1.65:1, 1.8:1, 2.0:1, 2.2:1 or 2.4:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, in step (1), the first sintering is carried out in a protective atmosphere at a temperature of 2150° C. to 2300° C. for 2 to 10 hours.

[0040] In the present invention, the temperature of the first sintering in step (1) is 2150°C to 2300°C, for example, it can be 2150°C, 2180°C, 2200°C, 2220°C, 2240°C, 2260°C, 2280°C or 2300°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0041] In the present invention, the first sintering time in step (1) is 2 to 10 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0042] Preferably, the protective atmosphere during the first sintering includes nitrogen and / or an inert gas.

[0043] Preferably, the inert gas includes any one of argon, nitrogen or helium, or a combination of at least two of them. Typical but non-limiting combinations include a combination of argon and nitrogen, a combination of nitrogen and helium, a combination of argon and helium, or a combination of argon, nitrogen and helium.

[0044] Preferably, step (1) further includes a heating step with a heating rate of 2 to 10°C / min before the first sintering. The heating rate can be, for example, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0045] Preferably, the mixing method in step (1) includes vacuum impregnation, and the vacuum degree during the vacuum impregnation is -0.0095MPa to 0.1MPa, and the time is 2h to 10h.

[0046] In the present invention, the vacuum degree during the vacuum impregnation in step (1) is -0.0095 MPa to 0.1 MPa, for example, it can be -0.0095 MPa, -0.008 MPa, -0.006 MPa, -0.004 MPa, -0.002 MPa, 0 MPa, 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa or 0.1 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] In the present invention, the time for vacuum impregnation in step (1) is 2 h to 10 h, for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] Preferably, the components of the silicon carbide slurry in step (1) include silicon carbide powder and a liquid dispersant.

[0049] Preferably, the average particle size of the silicon carbide powder is 10nm to 100nm, for example, it can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0050] Preferably, the liquid dispersant includes any one or a combination of at least two of silica sol, polyacrylic acid, sodium hexametaphosphate, sodium pyrophosphate or polyphosphate. Typical but non-limiting combinations include a combination of silica sol and polyacrylic acid, a combination of sodium hexametaphosphate and sodium pyrophosphate, a combination of polyacrylic acid and polyphosphate, a combination of sodium pyrophosphate and polyphosphate, or a combination of silica sol, polyacrylic acid and sodium hexametaphosphate.

[0051] Preferably, based on the mass of the silicon carbide slurry in step (1), the mass fraction of the silicon carbide powder in the silicon carbide slurry is 15wt%-60wt%, for example, it can be 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0052] Preferably, solid-liquid separation and drying are performed sequentially between the vacuum impregnation and the second sintering.

[0053] Preferably, the second sintering in step (1) is carried out in a protective atmosphere at a temperature of 1950° C. to 2150° C. for 2 to 10 hours.

[0054] In the present invention, the temperature of the second sintering in step (1) is 1950°C to 2150°C, for example, it can be 1950°C, 1980°C, 2000°C, 2020°C, 2040°C, 2060°C, 2080°C, 2100°C, 2120°C, 2140°C or 2150°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0055] In the present invention, the second sintering time in step (1) is 2 to 10 hours, for example, it can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0056] Preferably, the protective atmosphere during the second sintering includes nitrogen and / or an inert gas.

[0057] Preferably, the inert gas includes any one of argon, nitrogen or helium, or a combination of at least two of them. Typical but non-limiting combinations include a combination of argon and nitrogen, a combination of nitrogen and helium, a combination of argon and helium, or a combination of argon, nitrogen and helium.

[0058] Preferably, a heating step with a heating rate of 2 to 10°C / min is further included between the mixing in step (1) and the second sintering. The heating rate can be, for example, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0059] Preferably, the silicon carbide particle resin slurry in step (2) contains silicon carbide particles, a curing agent and a resin.

[0060] Preferably, based on the mass of the silicon carbide particle resin slurry in step (2), the mass fraction of the silicon carbide particles is 20wt%-40wt%, the mass fraction of the curing agent is 15wt%-25wt%, and the balance is resin.

[0061] In the present invention, taking the mass of the silicon carbide particle resin slurry in step (2) as 100%, the mass fraction of the silicon carbide particles is 20wt%-40wt%, and the mass fraction of the silicon carbide particles is 20wt%-40wt%, for example, it can be 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 32wt%, 34wt%, 36wt%, 38wt% or 40wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In the present invention, taking the mass of the silicon carbide particle resin slurry in step (2) as 100%, the mass fraction of the curing agent is 15wt% to 25wt%, for example, it can be 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt% or 25wt%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0063] Preferably, the silicon carbide particles in the silicon carbide particle resin slurry in step (2) include silicon carbide particles modified with a silane coupling agent; and the method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing the silicon carbide raw material in a silane coupling agent, and then sequentially performing solid-liquid separation and drying to obtain silicon carbide particles modified with a silane coupling agent.

[0064] Preferably, the mass of the silane coupling agent in the method is 1%-3% of the mass of the silicon carbide raw material, for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0065] Preferably, the curing agent comprises an amine curing agent.

[0066] Preferably, the amine curing agent includes ethylenediamine and / or m-xylylenediamine.

[0067] Preferably, the resin comprises epoxy resin, and the epoxy resin comprises bisphenol A epoxy resin.

[0068] Preferably, the bisphenol A epoxy resin includes E44 epoxy resin and / or cured E51 epoxy resin.

[0069] Preferably, the mixing method in step (2) includes vacuum impregnation, and the vacuum degree during the vacuum impregnation is -0.0095MPa to 0.1MPa, and the time is 2h to 10h.

[0070] In the present invention, the vacuum degree during the vacuum impregnation in step (2) is -0.0095 MPa to 0.1 MPa, for example, it can be -0.0095 MPa, -0.008 MPa, -0.006 MPa, -0.004 MPa, -0.002 MPa, 0 MPa, 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa or 0.1 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0071] In the present invention, the vacuum impregnation time in step (2) is 2 h to 10 h, for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0072] Preferably, the curing in step (2) includes step curing, and the step curing is performed in two stages.

[0073] Preferably, the curing temperature of the first stage in the step curing is 100° C. to 120° C., and the curing time is 90 min to 180 min.

[0074] In the present invention, the curing temperature of the first stage in the step curing is 100°C to 120°C, for example, it can be 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C or 120°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0075] In the present invention, the curing time of the first stage in the step curing is 90 min to 180 min, for example, it can be 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min or 180 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] Preferably, the curing temperature of the second stage in the step curing is 180° C. to 200° C., and the curing time is 30 min to 60 min.

[0077] In the present invention, the curing temperature of the second stage in the step curing is 180°C to 200°C, for example, it can be 180°C, 182°C, 184°C, 186°C, 188°C, 190°C, 192°C, 194°C, 196°C, 198°C or 200°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0078] In the present invention, the time of the second stage in the step curing is 30 minutes to 60 minutes, for example, it can be 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes or 60 minutes, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0079] Preferably, the curing in step (2) is carried out in a protective atmosphere.

[0080] Preferably, the protective atmosphere during the curing in step (2) comprises nitrogen and / or an inert gas.

[0081] Preferably, the inert gas includes any one of argon, nitrogen or helium, or a combination of at least two of them. Typical but non-limiting combinations include a combination of argon and nitrogen, a combination of nitrogen and helium, a combination of argon and helium, or a combination of argon, nitrogen and helium.

[0082] Preferably, the injection rate of the protective gas during curing is 10 mL / min to 100 mL / min, for example, 10 mL / min, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min or 100 mL / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0083] Preferably, the preparation method further comprises spraying after the step curing in step (2), and a self-repairing coating containing self-repairing microcapsules is formed after the spraying.

[0084] Preferably, the spraying comprises: spraying a slurry containing the microcapsule wall material and the microcapsule core material onto the surface of the material obtained after the step curing in step (2).

[0085] In the present invention, the principle of forming a self-healing coating containing self-healing microcapsules by spraying is: using a complex coacervation method to wrap the microcapsule core material (siloxane prepolymer) with a microcapsule wall material (polyurea formaldehyde and / or gelatin-gum arabic complex) to form microcapsules, and combining the stress-triggered dynamic repair mechanism to realize the self-healing function of the coating.

[0086] Preferably, the spraying further includes drying.

[0087] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises:

[0088] (1) mixing first silicon carbide particles with an average particle size of 20 μm to 100 μm and second silicon carbide particles with an average particle size of 0.5 μm to 1 μm in a mass ratio of (1.5 to 2.4):1 to obtain a mixture; then heating the mixture to 2150° C. to 2300° C. at a heating rate of 2 to 10° C. / min in a protective atmosphere and then holding the temperature for 2 to 10 hours to obtain a matrix skeleton;

[0089] Then, under a vacuum degree of -0.0095MPa to 0.1MPa, the obtained matrix skeleton is vacuum impregnated in silicon carbide slurry for 2h to 10h, and then solid-liquid separation and drying are carried out in sequence. Then, in a protective atmosphere, the dried solid is heated to 1950℃ to 2150℃ at a heating rate of 2 to 10℃ / min and then kept warm for 2h to 10h to obtain a recrystallized silicon carbide matrix.

[0090] The silicon carbide slurry comprises silicon carbide powder having an average particle size of 10 nm to 100 nm and a liquid dispersant, and the mass fraction of the silicon carbide powder in the silicon carbide slurry is 15 wt% to 60 wt% based on the mass of the silicon carbide slurry.

[0091] (2) Vacuum impregnating the recrystallized silicon carbide substrate obtained in step (1) into a silicon carbide particle resin slurry for 2 to 10 hours under a vacuum degree of -0.0095 MPa to 0.1 MPa; then curing the substrate at 100° C. to 120° C. for 90 to 180 minutes in a protective atmosphere, and then curing the substrate at 180° C. to 200° C. for 30 to 60 minutes to obtain a core;

[0092] The silicon carbide particle resin slurry includes silicon carbide particles modified with a silane coupling agent, an amine curing agent, and an epoxy resin. Based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with a silane coupling agent is 20wt%-40wt%, the mass fraction of the amine curing agent is 15wt%-25wt%, and the remainder is epoxy resin.

[0093] (3) spraying a slurry containing microcapsule wall material and microcapsule core material on the surface of the inner core obtained in step (2), forming a self-repairing coating containing self-repairing microcapsules on the surface of the inner core after spraying, and then drying to obtain the composite bulletproof material.

[0094] In a third aspect, the present invention provides a composite bullet-proof sheet, comprising the composite bullet-proof material according to the first aspect.

[0095] The method for preparing a composite bullet-proof sheet from a composite bullet-proof material in the present invention includes, but is not limited to: sequentially grinding and machining the composite bullet-proof material described in the first aspect.

[0096] In a fourth aspect, the present invention provides an application of the composite bullet-proof sheet according to the third aspect, wherein the composite bullet-proof sheet is used in the field of armor protection.

[0097] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0098] Compared with the prior art, the present invention has the following beneficial effects:

[0099] The composite bullet-proof material provided by the present invention comprises a composite material, wherein silicon carbide particles in the composite material are uniformly dispersed in an epoxy resin, forming a dual interface bond of mechanical interlocking and chemical bonding, thereby enhancing the shear strength of the interface between the silicon carbide particles and the epoxy resin, and endowing the composite material with excellent flexural strength and fracture toughness. Therefore, the composite material disposed on the surface and in the internal pores of the recrystallized silicon carbide matrix can compensate for the brittleness of the recrystallized silicon carbide matrix, thereby enhancing the flexural resistance and fracture toughness of the composite bullet-proof material. In addition, because the composite material composed of the cured resin and the silicon carbide particles has good corrosion resistance, after the composite material is filled in the internal pores of the recrystallized silicon carbide matrix, it can not only reduce the porosity of the composite bullet-proof material, but also block the penetration of corrosive media into the pores of the recrystallized silicon carbide matrix. Moreover, after the composite material covers the surface of the recrystallized silicon carbide matrix, it can to a certain extent block direct contact between the recrystallized silicon carbide matrix and the corrosive medium, thereby enhancing the corrosion resistance of the composite bullet-proof material.

[0100] In the composite bullet-proof material provided by the present invention, by covering the surface of the recrystallized silicon carbide matrix with a composite material and filling the internal pores of the recrystallized silicon carbide matrix with the composite material, not only the porosity of the composite bullet-proof material is reduced, but also the bending resistance, fracture toughness and corrosion resistance of the composite bullet-proof material are improved. DETAILED DESCRIPTION

[0101] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0102] Example 1

[0103] This embodiment provides a composite bullet-proof material, comprising a recrystallized silicon carbide matrix, and a composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix;

[0104] The composite material includes a cured E44 epoxy resin and silicon carbide particles modified with a silane coupling agent and having an average particle size of 50 nm. Based on the total mass of the composite material, the mass fraction of the silicon carbide particles modified with a silane coupling agent in the composite material is 30 wt %, and the remainder is the cured E44 epoxy resin.

[0105] The recrystallized silicon carbide matrix and the composite material form a core. The composite bulletproof material also includes a self-repairing coating with a thickness of 100 μm containing self-repairing microcapsules, and the self-repairing coating is coated on the surface of the core. The microcapsule wall material of the self-repairing microcapsules in the self-repairing coating is polyurea formaldehyde, and the microcapsule core material is octamethylcyclotetrasiloxane. The mass ratio of polyurea formaldehyde to octamethylcyclotetrasiloxane in the self-repairing coating is 1.5:1.

[0106] The preparation method of the composite bulletproof material comprises:

[0107] (1) mixing first silicon carbide particles with an average particle size of 60 μm and second silicon carbide particles with an average particle size of 0.7 μm at a mass ratio of 1.86:1 to obtain a mixture; then heating the mixture to 2200° C. at a heating rate of 5° C. / min in an argon atmosphere and holding the temperature for 8 h to obtain a matrix skeleton;

[0108] The obtained matrix skeleton was then vacuum-impregnated into silicon carbide slurry at a vacuum degree of 0.01 MPa for 6 hours, followed by solid-liquid separation and drying. The dried solid was then heated to 2100°C at a heating rate of 5°C / min in an argon atmosphere and kept at that temperature for 8 hours to obtain a recrystallized silicon carbide matrix.

[0109] The silicon carbide slurry comprises silicon carbide powder with an average particle size of 50 nm and silica sol, and based on the mass of the silicon carbide slurry, the mass fraction of the silicon carbide powder in the silicon carbide slurry is 50 wt %;

[0110] (2) Vacuum impregnating the recrystallized silicon carbide substrate obtained in step (1) into a silicon carbide particle resin slurry at a vacuum degree of 0.01 MPa for 6 hours; then curing the substrate at 110° C. for 120 minutes and then at 190° C. for 50 minutes in a nitrogen atmosphere to obtain a core;

[0111] The silicon carbide particle resin slurry includes silicon carbide particles modified with a silane coupling agent, an ethylenediamine amine curing agent, and an E44 epoxy resin. Based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with a silane coupling agent is 30wt%, the mass fraction of the ethylenediamine curing agent is 20wt%, and the balance is the E44 epoxy resin.

[0112] The method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing a silicon carbide raw material in a silane coupling agent (the mass of the silane coupling agent is 2% of the mass of the silicon carbide raw material), and then sequentially performing solid-liquid separation and drying to obtain silicon carbide particles modified with a silane coupling agent;

[0113] (3) spraying a slurry containing polyurea formaldehyde and octamethylcyclotetrasiloxane on the surface of the core obtained in step (2), forming a self-repairing coating containing self-repairing microcapsules on the surface of the core after spraying, and then drying to obtain the composite bulletproof material.

[0114] Example 2

[0115] This embodiment provides a composite bullet-proof material, comprising a recrystallized silicon carbide matrix, and a composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix;

[0116] The composite material includes a cured E51 epoxy resin and silicon carbide particles modified with a silane coupling agent and having an average particle size of 10 nm. Based on the total mass of the composite material, the mass fraction of the silicon carbide particles modified with a silane coupling agent in the composite material is 20 wt %, and the remainder is the cured E51 epoxy resin.

[0117] The recrystallized silicon carbide matrix and the composite material form a core, and the composite bulletproof material also includes a self-healing coating with a thickness of 200 μm containing self-healing microcapsules, and the self-healing coating is coated on the surface of the core; the microcapsule wall material of the self-healing microcapsules in the self-healing coating is a gelatin-gum arabic complex (the mass ratio of gelatin to gum arabic is 1:1), and the microcapsule core material is decamethylcyclopentasiloxane, and the mass ratio of the gelatin-gum arabic complex to decamethylcyclopentasiloxane in the self-healing coating is 2.2:1.

[0118] The preparation method of the composite bulletproof material comprises:

[0119] (1) mixing first silicon carbide particles with an average particle size of 100 μm and second silicon carbide particles with an average particle size of 1 μm at a mass ratio of 2.4:1 to obtain a mixture; then heating the mixture to 2150° C. at a heating rate of 2° C. / min in a nitrogen atmosphere and holding the mixture for 10 h to obtain a matrix skeleton;

[0120] The obtained matrix skeleton was then vacuum-impregnated into silicon carbide slurry at a vacuum degree of -0.0095 MPa for 2 hours, followed by solid-liquid separation and drying. The dried solid was then heated to 1950°C at a heating rate of 2°C / min in a nitrogen atmosphere and kept at that temperature for 10 hours to obtain a recrystallized silicon carbide matrix.

[0121] The silicon carbide slurry comprises silicon carbide powder with an average particle size of 100 nm and polyacrylic acid, and the mass fraction of the silicon carbide powder in the silicon carbide slurry is 60 wt % based on the mass of the silicon carbide slurry.

[0122] The method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing a silicon carbide raw material in a silane coupling agent (the mass of the silane coupling agent is 2% of the mass of the silicon carbide raw material), and then sequentially performing solid-liquid separation and drying to obtain silicon carbide particles modified with a silane coupling agent;

[0123] (2) Vacuum impregnating the recrystallized silicon carbide substrate obtained in step (1) into a silicon carbide particle resin slurry at a vacuum degree of -0.0095 MPa for 10 hours; then curing the slurry at 100° C. for 180 minutes and then at 200° C. for 30 minutes in a nitrogen atmosphere to obtain a core;

[0124] The silicon carbide particle resin slurry includes silicon carbide particles modified with a silane coupling agent, a meta-xylylenediamine curing agent, and an E51 epoxy resin. Based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with a silane coupling agent is 20wt%, the mass fraction of the meta-xylylenediamine curing agent is 25wt%, and the balance is the E51 epoxy resin.

[0125] The method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing a silicon carbide raw material in a silane coupling agent (the mass of the silane coupling agent is 3% of the mass of the silicon carbide raw material), and then sequentially performing solid-liquid separation and drying to obtain silicon carbide particles modified with a silane coupling agent;

[0126] (3) spraying a slurry containing a gelatin-gum arabic complex (the mass ratio of gelatin to gum arabic is 1:1) and decamethylcyclopentasiloxane on the surface of the inner core obtained in step (2), forming a self-repairing coating containing self-repairing microcapsules on the surface of the inner core after spraying, and then drying to obtain the composite bulletproof material.

[0127] Example 3

[0128] This embodiment provides a composite bullet-proof material, comprising a recrystallized silicon carbide matrix, and a composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix;

[0129] The composite material includes a cured E44 epoxy resin and silicon carbide particles modified with a silane coupling agent and having an average particle size of 100 nm. Based on the total mass of the composite material, the mass fraction of the silicon carbide particles modified with a silane coupling agent in the composite material is 40 wt %, and the remainder is the cured E44 epoxy resin.

[0130] The recrystallized silicon carbide matrix and the composite material form a core. The composite bulletproof material also includes a self-repairing coating with a thickness of 50 μm containing self-repairing microcapsules, and the self-repairing coating is coated on the surface of the core. The microcapsule wall material of the self-repairing microcapsules in the self-repairing coating is polyurea formaldehyde, and the microcapsule core material is dodecamethylcyclohexasiloxane. The mass ratio of polyurea formaldehyde to dodecamethylcyclohexasiloxane in the self-repairing coating is 1:1.

[0131] The preparation method of the composite bulletproof material comprises:

[0132] (1) mixing first silicon carbide particles with an average particle size of 20 μm and second silicon carbide particles with an average particle size of 0.5 μm at a mass ratio of 1.5:1 to obtain a mixture; then heating the mixture to 2300° C. at a heating rate of 10° C. / min in a nitrogen atmosphere and holding the temperature for 2 h to obtain a matrix skeleton;

[0133] The obtained matrix skeleton was then vacuum-impregnated in silicon carbide slurry under a vacuum degree of 0.1 MPa for 10 hours, followed by solid-liquid separation and drying. The dried solid was then heated to 2150°C at a heating rate of 10°C / min in a nitrogen atmosphere and kept at that temperature for 2 hours to obtain a recrystallized silicon carbide matrix.

[0134] The silicon carbide slurry includes silicon carbide powder with an average particle size of 10 nm and silica sol, and the mass fraction of the silicon carbide powder in the silicon carbide slurry is 15 wt % based on the mass of the silicon carbide slurry.

[0135] (2) Vacuum impregnating the recrystallized silicon carbide substrate obtained in step (1) into a silicon carbide particle resin slurry under a vacuum degree of 0.1 MPa for 2 hours; then curing the substrate at 120° C. for 90 minutes and then at 180° C. for 60 minutes in a nitrogen atmosphere to obtain a core;

[0136] The silicon carbide particle resin slurry comprises silicon carbide particles modified with a silane coupling agent, an ethylenediamine curing agent, and an E44 epoxy resin. Based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with a silane coupling agent is 40 wt %, the mass fraction of the ethylenediamine curing agent is 15 wt %, and the balance is the E44 epoxy resin.

[0137] The method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing a silicon carbide raw material in a silane coupling agent (the mass of the silane coupling agent is 1% of the mass of the silicon carbide raw material), and then sequentially performing solid-liquid separation and drying to obtain silicon carbide particles modified with a silane coupling agent;

[0138] (3) spraying a slurry containing polyurea formaldehyde and dodecamethylcyclohexasiloxane on the surface of the inner core obtained in step (2), forming a self-repairing coating containing self-repairing microcapsules on the surface of the inner core after spraying, and then drying to obtain the composite bulletproof material.

[0139] Example 4

[0140] This embodiment provides a composite bullet-proof material, which is the same as Example 1 except that step (1) of the preparation method of the composite bullet-proof material is omitted, namely, "the obtained matrix skeleton is vacuum-impregnated in silicon carbide slurry under a vacuum degree of 0.01 MPa for 6 hours, and then solid-liquid separation and drying are carried out in sequence, and then the solid obtained after drying is heated to 2100° C. at a heating rate of 5° C. / min in an argon atmosphere and kept warm for 8 hours."

[0141] Example 5

[0142] This embodiment provides a composite bulletproof material, except that the mass fraction of silicon carbide particles modified with a silane coupling agent in the composite material is 10 wt %;

[0143] That is, in step (2) of the method for preparing the composite bullet-proof material, based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with the silane coupling agent is 10wt%, the mass fraction of the ethylenediamine curing agent is 30wt%, and the balance is E44 epoxy resin. The rest is the same as in Example 1.

[0144] Example 6

[0145] This embodiment provides a composite bulletproof material, except that the mass fraction of silicon carbide particles modified with a silane coupling agent in the composite material is 50 wt %;

[0146] That is, in step (2) of the method for preparing the composite bullet-proof material, based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with the silane coupling agent is 50wt%, the mass fraction of the ethylenediamine curing agent is 10wt%, and the balance is E44 epoxy resin. The rest is the same as in Example 1.

[0147] Example 7

[0148] This embodiment provides a composite bulletproof material, except that the silicon carbide particles modified with a silane coupling agent in the composite material are replaced with silicon carbide particles of equal mass and an average particle size of 50 nm;

[0149] That is, in step (2) of the method for preparing the composite bullet-proof material, the silicon carbide particles modified with the silane coupling agent in the silicon carbide particle resin slurry are replaced with silicon carbide raw materials, and the rest are the same as in Example 1.

[0150] Example 8

[0151] This embodiment provides a composite bulletproof material, which is the same as that of Example 1 except that the average particle size of the silicon carbide particles modified with a silane coupling agent in the composite material is 5 nm.

[0152] Example 9

[0153] This embodiment provides a composite bulletproof material, which is the same as that of Example 1 except that the average particle size of the silicon carbide particles modified with a silane coupling agent in the composite material is 150 nm.

[0154] Example 10

[0155] This embodiment provides a composite bulletproof material, except that the self-repairing coating containing self-repairing microcapsules having a thickness of 100 μm is omitted;

[0156] That is, except for omitting step (3) of the method for preparing the composite bullet-proof material, the rest is the same as in Example 1.

[0157] Comparative Example 1

[0158] This comparative example provides a composite bullet-proof material, except that the composite material filled in the internal pores of the recrystallized silicon carbide matrix and covered on the surface of the recrystallized silicon carbide matrix is ​​omitted from the composite bullet-proof material;

[0159] That is, except for omitting step (2) of the method for preparing the composite bullet-proof material, the rest is the same as in Example 1.

[0160] Comparative Example 2

[0161] This comparative example provides a composite bulletproof material, except that the composite material including the cured resin and silicon carbide particles is replaced with a simple cured resin;

[0162] That is, the silicon carbide particle resin slurry in step (2) of the method for preparing the composite bullet-proof material is replaced by a resin slurry consisting only of ethylenediamine curing agent and E44 epoxy resin in a mass ratio of 2:5, and the rest is the same as in Example 1.

[0163] Comparative Example 3

[0164] This comparative example provides a composite bullet-proof material, except that the composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix is ​​omitted; and the self-repairing coating containing self-repairing microcapsules is omitted;

[0165] That is, the step (1) of the method for preparing the composite bullet-proof material is omitted, "then under a vacuum degree of 0.1 MPa, vacuum-immersing the obtained matrix skeleton in a silicon carbide slurry for 10 hours, then sequentially performing solid-liquid separation and drying, and then heating the dried solid to 2150° C. at a heating rate of 10° C. / min in a nitrogen atmosphere and then holding the temperature for 2 hours to obtain a recrystallized silicon carbide matrix."

[0166] Except for omitting step (2) and step (3), the rest are the same as in Example 1.

[0167] The porosity of the recrystallized silicon carbide matrix in the composite bullet-proof materials provided in the above embodiments and comparative examples was tested to obtain the porosity of the recrystallized silicon carbide matrix. As shown in Table 1;

[0168] The composite bullet-proof materials provided in the above embodiments and comparative examples were polished and sized in sequence to obtain recrystallized silicon carbide bullet-proof sheets. The porosity, flexural strength, fracture toughness and corrosion resistance of the recrystallized silicon carbide bullet-proof sheets obtained in the above embodiments and comparative examples were then tested to obtain the porosity of the recrystallized silicon carbide bullet-proof sheets. The flexural strength, fracture toughness and corrosion rate are shown in Table 1. Among them, the porosity test was conducted by mercury intrusion porosimetry; the flexural strength was tested according to ASTM C1161; the fracture toughness was tested according to ASTM E399; the corrosion rate was calculated by measuring the weight of the recrystallized silicon carbide bulletproof sheet before placing it in a 4 mol / L NaOH solution for 72 hours, separating the solid and liquid, and then drying it. The test standard was ASTM G31.

[0169] Table 1

[0170]

[0171] From Table 1, we can get:

[0172] (1) The composite bullet-proof materials and their recrystallized silicon carbide matrices provided in Examples 1 to 3 of the present invention all have low porosity, and the composite bullet-proof materials exhibit high flexural strength, fracture toughness, and strong corrosion resistance;

[0173] (2) By comparing Example 1 with Example 4, it can be seen that in step (1) of the preparation method of the present invention, by first sintering the mixture of two silicon carbide particles with different particle sizes and then mixing it with the silicon carbide slurry for sintering, the porosity of the prepared recrystallized silicon carbide matrix is ​​significantly reduced, and the density of the recrystallized silicon carbide matrix is ​​increased, which is beneficial to improving the impact resistance of the prepared composite bullet-proof material;

[0174] (3) By comparing Example 1 with Examples 5 and 6, it can be seen that in the present invention, the mass fraction of silicon carbide particles in the composite material affects the performance of the composite bullet-proof material; when the mass fraction of silicon carbide particles in the composite material is 20wt% to 40wt%, the composite bullet-proof material exhibits better performance. This is because when the mass fraction of silicon carbide particles is too low, the pores of the recrystallized silicon carbide matrix cannot be fully filled, resulting in an increase in the porosity of the composite bullet-proof material and a reduction in properties such as density and flexural strength; and when the mass fraction of silicon carbide particles is too high, the fluidity of the silicon carbide resin slurry deteriorates, the slurry viscosity increases, and vacuum impregnation cannot completely fill the pores. Moreover, when the solid content is too high, the silicon carbide nanoparticles will also form agglomerates and become crack sources, thereby reducing the comprehensive properties of the composite bullet-proof material such as fracture toughness.

[0175] (4) By comparing Example 1 with Example 7, it can be seen that in the present invention, when the silicon carbide particles modified with a silane coupling agent are used as the silicon carbide particles in the composite material, the composite bullet-proof material exhibits better performance. This is because by modifying the surface of the nano-silicon carbide powder, the nano-silicon carbide particles and the epoxy resin form a dual interface of mechanical interlocking and chemical bonding, which improves the dispersibility of the nano-silicon carbide powder in the epoxy resin, and is conducive to enhancing the corrosion resistance and fracture toughness of the recrystallized silicon carbide bulletproof sheet, enhancing the quality stability of the recrystallized silicon carbide bulletproof sheet, and further extending the service life of the recrystallized silicon carbide bulletproof sheet;

[0176] (5) By comparing Example 1 with Examples 8 and 9, it can be seen that in the present invention, the average particle size of the silicon carbide particles modified with the silane coupling agent in the composite material will affect the performance of the composite bullet-proof material; when the average particle size of the silicon carbide particles modified with the silane coupling agent is 10nm to 100nm, the composite bullet-proof material shows better performance. This is because the specific surface area of ​​the silicon carbide particles with a particle size of 10 to 100nm far exceeds that of the micron-sized particles. The Si-OH formed by the silane coupling agent on the surface of the silicon carbide particles condenses with the -OH / -NH2 groups of the epoxy resin to form Si-OC / Si-O-Si covalent bonds. The bonding density increases significantly with the increase of the specific surface area. At the same time, the silicon carbide particles with a particle size of 10 to 100nm act as a rigid barrier. When the material is impacted by external force, it can force the crack propagation path to deflect, extend the crack length, consume energy, and have a toughening effect; however, if the average particle size of the silicon carbide particles is too small, the agglomeration phenomenon between the silicon carbide particles is serious, which will lead to an increase in interface pores and a decrease in flexural strength. At the same time, it will also affect the dispersibility of nano-silicon carbide powder in epoxy resin and reduce the uniform distribution of silicon carbide resin slurry in the recrystallized silicon carbide matrix; and when the average particle size of the silicon carbide particles is too large, it cannot fully fill the pores of the recrystallized silicon carbide matrix, and the specific surface area of ​​the silicon carbide particles is insufficient, the bonding density is low, and cracks are likely to directly penetrate the particles; therefore, if the average particle size of the silicon carbide particles modified with silane coupling agent is too large or too small, the comprehensive performance of the composite bullet-proof material will be reduced;

[0177] (6) By comparing Example 1 with Example 10, it can be seen that in the present invention, when the composite bullet-proof material is impacted by external force, microcracks will be generated. When the microcracks expand, the self-repairing microcapsules in the self-repairing coating of the composite bullet-proof material will release prepolymers, increasing the self-repair rate, thereby significantly improving the mechanical properties of the composite bullet-proof material and extending the service life of the composite bullet-proof material.

[0178] (7) By comparing Example 1 with Comparative Examples 1 to 3, it can be seen that the composite bullet-proof material provided by the present invention contains a composite material, and the silicon carbide particles in the composite material are uniformly dispersed in the epoxy resin, forming a dual interface combination of mechanical interlocking and chemical bonding, thereby enhancing the shear strength of the interface between the silicon carbide particles and the epoxy resin, and making the composite material have excellent flexural strength and fracture toughness; therefore, the composite material arranged on the surface and internal pores of the recrystallized silicon carbide matrix can compensate for the brittleness of the recrystallized silicon carbide matrix, thereby enhancing the flexural resistance and fracture toughness of the composite bullet-proof material; in addition, since the composite material composed of the cured resin and the silicon carbide particles has good corrosion resistance, after the composite material is filled in the internal pores of the recrystallized silicon carbide matrix, it can not only reduce the porosity of the composite bullet-proof material, but also block the penetration of the corrosive medium into the pores of the recrystallized silicon carbide matrix, and after the composite material is covered on the surface of the recrystallized silicon carbide matrix, it can to a certain extent block the direct contact between the recrystallized silicon carbide matrix and the corrosive medium, thereby enhancing the corrosion resistance of the composite bullet-proof material;

[0179] In the composite bullet-proof material provided by the present invention, by covering the surface of the recrystallized silicon carbide matrix with a composite material and filling the internal pores of the recrystallized silicon carbide matrix with the composite material, not only the porosity of the composite bullet-proof material is reduced, but also the bending resistance, fracture toughness and corrosion resistance of the composite bullet-proof material are improved.

[0180] 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 thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A composite bulletproof material, characterized in that: The composite bulletproof material includes a recrystallized silicon carbide matrix and a composite material filling the internal pores of the recrystallized silicon carbide matrix and covering the surface of the recrystallized silicon carbide matrix; The composite material includes cured resin and silicon carbide particles.

2. The composite bulletproof material according to claim 1, characterized in that: The porosity of the recrystallized silicon carbide substrate is ≤5%.

3. The composite bulletproof material according to claim 1, characterized in that: Based on the total mass of the composite material, the mass fraction of the silicon carbide particles in the composite material is 20wt% to 40wt%, and the remainder is cured resin; Preferably, the silicon carbide particles in the composite material include silicon carbide particles modified with a silane coupling agent; Preferably, the average particle size of the silicon carbide particles in the composite material is 10 nm to 100 nm; Preferably, the curable resin comprises a curable epoxy resin.

4. The composite bullet-proof material according to any one of claims 1 to 3, characterized in that: The composite bulletproof material further comprises a self-repairing coating, wherein the self-repairing coating contains self-repairing microcapsules; The recrystallized silicon carbide matrix and the composite material form a core, and the self-repairing coating is coated on the surface of the core; Preferably, the thickness of the self-repairing coating is 50 μm to 200 μm; Preferably, the microcapsule wall material of the self-repairing microcapsules in the self-repairing coating comprises polyurea formaldehyde and / or gelatin-gum arabic composite, and the microcapsule core material comprises silicone prepolymer; Preferably, the mass ratio of the microcapsule wall material to the microcapsule core material in the self-repairing coating is (1-2.2):

1.

5. A method for preparing the composite bullet-proof material according to any one of claims 1 to 4, characterized in that: The preparation method comprises: (1) performing a first sintering on a mixture of two silicon carbide particles having different particle sizes to obtain a matrix skeleton; then mixing a silicon carbide slurry with the obtained matrix skeleton and performing a second sintering to obtain a recrystallized silicon carbide matrix; (2) Mixing the recrystallized silicon carbide matrix obtained in step (1) with the silicon carbide particle resin slurry, and then curing the mixture to obtain the composite bulletproof material.

6. The preparation method according to claim 5, characterized in that The mixture in step (1) comprises first silicon carbide particles having an average particle size of 20 μm to 100 μm and second silicon carbide particles having an average particle size of 0.5 μm to 1 μm; Preferably, in the mixture, the mass ratio of the first silicon carbide particles to the second silicon carbide particles is (1.5-2.4):1; Preferably, the first sintering in step (1) is carried out in a protective atmosphere at a temperature of 2150° C. to 2300° C. for 2 to 10 hours; Preferably, the mixing method in step (1) includes vacuum impregnation, the vacuum degree during the vacuum impregnation is -0.0095MPa to 0.1MPa, and the time is 2h to 10h; Preferably, the components of the silicon carbide slurry in step (1) include silicon carbide powder and a liquid dispersant; Preferably, the average particle size of the silicon carbide powder is 10 nm to 100 nm; Preferably, based on the mass of the silicon carbide slurry in step (1), the mass fraction of the silicon carbide powder in the silicon carbide slurry is 15wt%-60wt%; Preferably, the second sintering in step (1) is carried out in a protective atmosphere at a temperature of 1950° C. to 2150° C. for 2 to 10 hours.

7. The preparation method according to claim 5, characterized in that The silicon carbide particle resin slurry in step (2) comprises silicon carbide particles, a curing agent and a resin; Preferably, based on the mass of the silicon carbide particle resin slurry in step (2), the mass fraction of the silicon carbide particles is 20wt%-40wt%, the mass fraction of the curing agent is 15wt%-25wt%, and the balance is resin; Preferably, the silicon carbide particles in the silicon carbide particle resin slurry in step (2) include silicon carbide particles modified with a silane coupling agent; The method for preparing the silicon carbide particles modified with a silane coupling agent comprises: dispersing a silicon carbide raw material in a silane coupling agent, and then sequentially performing solid-liquid separation and drying to obtain the silicon carbide particles modified with a silane coupling agent; Preferably, in the method, the mass of the silane coupling agent is 1%-3% of the mass of the silicon carbide raw material; Preferably, the mixing method in step (2) includes vacuum impregnation, the vacuum degree during the vacuum impregnation is -0.0095MPa to 0.1MPa, and the time is 2h to 10h; Preferably, the curing in step (2) includes step curing, and the step curing is performed in two stages; Preferably, the curing temperature of the first stage in the step curing is 100° C. to 120° C., and the curing time is 90 min to 180 min; Preferably, the curing temperature of the second stage in the step curing is 180° C. to 200° C., and the curing time is 30 min to 60 min; Preferably, the preparation method further comprises spraying after the step curing in step (2), and a self-repairing coating containing self-repairing microcapsules is formed after the spraying.

8. The preparation method according to claim 5, characterized in that The preparation method comprises: (1) mixing first silicon carbide particles with an average particle size of 20 μm to 100 μm and second silicon carbide particles with an average particle size of 0.5 μm to 1 μm in a mass ratio of (1.5 to 2.4):1 to obtain a mixture; then heating the mixture to 2150° C. to 2300° C. at a heating rate of 2 to 10° C. / min in a protective atmosphere and then holding the temperature for 2 to 10 hours to obtain a matrix skeleton; Then, under a vacuum degree of -0.0095MPa to 0.1MPa, the obtained matrix skeleton is vacuum impregnated in silicon carbide slurry for 2h to 10h, and then solid-liquid separation and drying are carried out in sequence. Then, in a protective atmosphere, the dried solid is heated to 1950℃ to 2150℃ at a heating rate of 2 to 10℃ / min and then kept warm for 2h to 10h to obtain a recrystallized silicon carbide matrix. The silicon carbide slurry comprises silicon carbide powder having an average particle size of 10 nm to 100 nm and a liquid dispersant, and the mass fraction of the silicon carbide powder in the silicon carbide slurry is 15 wt% to 60 wt% based on the mass of the silicon carbide slurry. (2) Vacuum impregnating the recrystallized silicon carbide substrate obtained in step (1) into a silicon carbide particle resin slurry for 2 to 10 hours under a vacuum degree of -0.0095 MPa to 0.1 MPa; then curing the substrate at 100° C. to 120° C. for 90 to 180 minutes in a protective atmosphere, and then curing the substrate at 180° C. to 200° C. for 30 to 60 minutes to obtain a core; The silicon carbide particle resin slurry comprises silicon carbide particles modified with a silane coupling agent, an amine curing agent, and an epoxy resin. Based on the mass of the silicon carbide particle resin slurry, the mass fraction of the silicon carbide particles modified with a silane coupling agent is 20wt%-40wt%, the mass fraction of the amine curing agent is 15wt%-25wt%, and the remainder is epoxy resin. (3) spraying a slurry containing microcapsule wall material and microcapsule core material on the surface of the inner core obtained in step (2), forming a self-repairing coating containing self-repairing microcapsules on the surface of the inner core after spraying, and then drying to obtain the composite bulletproof material.

9. A composite bulletproof sheet, characterized in that: The composite bullet-proof sheet comprises the composite bullet-proof material according to any one of claims 1 to 4.

10. An application of the composite bulletproof sheet according to claim 9, characterized in that: The composite bulletproof sheet is used in the field of armor protection.

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