A special bulletproof ceramic and its preparation method

Abstract

The present invention provides a special anti-ballistic ceramic and a preparation method thereof. A columnar coating is superposed and prepared on the surface of a metal transition layer of a ceramic matrix by electron beam physical vapor deposition method, and then a layered coating is sprayed and superposed by spraying a hybrid feedstock on the surface of the columnar coating by supersonic flame spraying method. The hybrid feedstock makes the layered coating contain ceramic particles, diamond particles and metal particles with different particle sizes. The present invention uses the columnar coating with a columnar microstructure as a support structure to improve the overall compressive strength of the material at the moment of projectile contact, and can deflect the penetration trajectory of the projectile; the layered structure of the layered coating and the hard particles with different materials / particle sizes can cause diffuse scattering when the shock wave propagates, weakening the damage of the shock wave to the interface of the ceramic composite armor; at the same time, under the support of the columnar coating, the ceramic and diamond hard particles can give full play to their hardness advantages during the high-speed impact of the projectile and cause damage to the projectile.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface modification, and particularly relates to a special bulletproof ceramic and a preparation method thereof. Background Art

[0002] Ceramic materials have the advantages of high hardness, high strength, wear resistance and low density. During the penetration of a projectile, the high hardness and high compressive strength of the ceramic can break and abrade the projectile, causing the projectile to become blunt and achieving the bulletproof function. Therefore, ceramics have important applications in lightweight composite armor. However, with the continuous improvement of the penetration ability of projectiles, the requirements for the bulletproof performance of ceramics are getting higher and higher. The research and development of high-hardness and high-strength bulletproof ceramics has become one of the hotspots. However, limited by the development of new materials, the research and development cycle of high-hardness and high-strength bulletproof ceramics is long and the investment cost is high, making it difficult to achieve effective application in the short term.

[0003] Research has found that preparing a coating on the surface of a substrate can endow the substrate with excellent properties beyond its inherent properties, which is one of the most effective methods to improve material properties. Summary of the Invention

[0004] In view of this, the present invention proposes a special bulletproof ceramic and a preparation method thereof. By using coating technology and through the design of materials and structures, a high-performance coating is prepared on the surface of the bulletproof ceramic substrate to improve the bulletproof ability of the ceramic. Specifically:

[0005] A preparation method of a special bulletproof ceramic, comprising:

[0006] Step 1: Clean the surface of the ceramic substrate with alcohol, clean it with ultrasonic waves, and then dry it with a hair dryer;

[0007] Step 2: Prepare a metal transition layer on the surface of the ceramic substrate by physical vapor deposition (PVD);

[0008] Step 3: Stack and prepare a columnar coating on the surface of the metal transition layer by electron beam physical vapor deposition (EB-PVD);

[0009] Step 4: Spray a hybrid feed on the surface of the columnar coating by high-velocity oxy-fuel spraying (HVOF) to stack and prepare a layered coating. The hybrid feed makes the layered coating contain ceramic particles, diamond particles and metal particles with different particle sizes;

[0010] Step 5: Vacuum heat treatment.

[0011] The present invention makes full use of the projectile penetration mechanism to design the above coating materials and structures. A columnar coating with a columnar microstructure is used as the supporting structure to enhance the overall compressive strength of the material at the moment of projectile contact. A layered coating with a layered microstructure is prepared on the columnar coating as the surface structure of the special anti-ballistic ceramic. The feed of the layered coating contains ceramic particles (hard phase), diamond particles (hard phase), and metal particles (bonding phase) of different particle sizes. The layered structure and hard particles of different materials / particle sizes can cause diffuse scattering when the shock wave propagates, weakening the damage of the shock wave to the interface of the ceramic composite armor. At the same time, the ceramic and diamond hard particles can give full play to their hardness advantages under the support of the columnar coating and cause damage to the projectile when the projectile impacts at high speed. In addition, during the projectile penetration process, when the columnar crystals inside the columnar coating break, they can deflect the projectile penetration trajectory. Therefore, the design of this special anti-ballistic ceramic can effectively improve the anti-ballistic ability of the ceramic.

[0012] Preferably, the coating material of the columnar coating is Al2O3, SiC, TiBN, and the coating thickness is 200 - 300μm.

[0013] Preferably, the spraying raw material of the layered coating, i.e., the mixed feed, is a mixed powder of the hard phase and the bonding phase, and the coating thickness is 200 - 300μm.

[0014] Furthermore, the preparation method of the mixed powder is as follows: Mix Al2O3, diamond powder, and Ni powder in a mass ratio of 3:1:6. The volume ratio of Al2O3 with a particle size of 10 - 20μm to alumina with a particle size of 40 - 50μm is 1:1, the volume ratio of diamond with a particle size of 5 - 10μm to diamond with a particle size of 20 - 30μm is 1:1, and the particle size of Ni powder is 45 - 60μm. Prepare the mixed powder into a slurry, and then use the spray granulation method to prepare the mixed powder.

[0015] Preferably, the temperature of the vacuum heat treatment is 500°C, and the heat preservation duration is 8h.

[0016] The process parameters of the electron beam physical vapor deposition method (EB - PVD) are: deposition rate 2 - 3μm / min, the ratio of the substrate temperature to the melting point of the target is 0.3 - 0.5, the vacuum degree is 6 - 8Pa, and the electron beam current intensity is 1 - 2A.

[0017] The process parameters of the high - velocity oxygen - fuel spraying method (HVOF) are: the flow rate of the fuel gas (C2H2) is 20 - 25L / min, the flow rate of oxygen is 200 - 230L / min, and the spraying distance is 200 - 300mm.

[0018] The metal transition layer is a Ti transition layer.

[0019] A special anti - ballistic ceramic is prepared by the method described above.

[0020] Specifically, a metal transition layer, a columnar coating, and a layered coating are sequentially stacked on the surface of the ceramic matrix from bottom to top.

[0021] The beneficial effects of the present invention are as follows:

[0022] (1) The columnar coating can serve as a support structure to enhance the overall compressive strength of the material at the moment of projectile contact; with the support of the columnar coating, the ceramics and diamond hard particles can give full play to their hardness advantages. The two work together to increase the damage ability to the projectile.

[0023] (2) The layered structure of the layered coating and the hard particles of different materials / grain sizes can cause diffuse scattering when the shock wave propagates, weakening the damage to the interface of the ceramic composite armor by the shock wave.

[0024] (3) During the projectile penetration process, when fractures occur inside the columnar coating, it can deflect the projectile penetration trajectory and improve the bulletproof ability of the ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0026] Figure 1 is a cross-sectional schematic diagram of the present invention;

[0027] Figure 2 is a micrograph of the layered coating prepared in the embodiment of the present invention;

[0028] Figure 3 is a micrograph of the columnar coating prepared in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0030] The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0031] In this embodiment, B4C ceramics are used as the ceramic matrix. After cleaning the surface of the ceramic matrix, a transition layer is prepared by PVD, a columnar coating is prepared by EB-PVD, and a layered coating is sprayed with a hybrid feedstock by HVOF in sequence. The combination of the layer / column composite structure can significantly improve the bulletproof ability.

[0032] Specifically, a special bulletproof ceramic with a total coating thickness of 450 μm is prepared:

[0033] Clean the surface of the B4C ceramic substrate with alcohol, and then use ultrasonic cleaning. After that, dry it with a hair dryer.

[0034] Prepare a Ti transition layer on the surface of the treated B4C ceramic substrate by the PVD method, and the thickness of the transition layer is 50 μm.

[0035] Prepare a SiC columnar coating on the Ti transition layer, and the thickness of the coating is 200 μm. The SiC columnar coating is prepared by the EB - PVD method, and the target is a SiC tablet with a purity of 98%. The process parameters are: the vacuum degree is 7 Pa, the deposition rate is 2 μm / min, the ratio of the substrate temperature to the melting point of the target is 0.4, and the electron beam current intensity is 2 A.

[0036] Then prepare a layered coating on the SiC columnar coating, and the thickness of the coating is 200 μm. The layered coating is prepared by spraying a hybrid feedstock using the HVOF method. The process parameters are: the flow rate of the fuel gas (C2H2) is 23 L / min, the flow rate of oxygen is 220 L / min, and the spraying distance is 280 mm. The preparation method of the hybrid feedstock is as follows: Mix Al2O3, diamond powder, and Ni powder in a mass ratio of 3:1:6. Among them, the volume ratio of 10 - 20 μm - sized Al2O3 to 40 - 50 μm - sized alumina is 1:1, the volume ratio of 5 - 10 μm - sized diamond to 20 - 30 μm - sized diamond is 1:1, and the particle size of Ni powder is 45 - 60 μm. Prepare the mixed powder into a slurry, and then use the spray granulation method to prepare a hybrid powder.

[0037] After the layered coating is prepared, perform vacuum heat treatment at a temperature of 500 °C for a holding time of 8 h.

[0038] The following table shows the comparison of the test results of the special bulletproof ceramic in this embodiment and the traditional bulletproof ceramic. It can be seen that the corresponding performance has been greatly improved.

[0039]

[0040]

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a special bulletproof ceramic, characterized in that, Including: Step 1: Clean the surface of the ceramic substrate with alcohol, clean it with ultrasonic waves, and then dry it with a hair dryer. Step 2: Prepare a metal transition layer on the surface of the ceramic substrate by physical vapor deposition. Step 3: Superpose and prepare a columnar coating on the surface of the metal transition layer by electron beam physical vapor deposition. Step 4: Spray a hybrid feedstock on the surface of the columnar coating by supersonic flame spraying to superpose and prepare a layered coating. The hybrid feedstock makes the layered coating contain ceramic particles, diamond particles and metal particles of different particle sizes. Step 5: Vacuum heat treatment.

2. The preparation method of a special bulletproof ceramic according to claim 1, characterized in that The hybrid feedstock for preparing the layered coating is a mixed powder of hard phase and binder phase, and the coating thickness is 200 - 300μm.

3. The preparation method of a special bulletproof ceramic according to claim 2, characterized in that, The preparation method of the mixed powder is as follows: Mix Al2O3, diamond powder and Ni powder according to a mass ratio of 3:1:

6. The volume ratio of Al2O3 with a particle size of 10 - 20μm to alumina with a particle size of 40 - 50μm is 1:1, the volume ratio of diamond with a particle size of 5 - 10μm to diamond with a particle size of 20 - 30μm is 1:1, and the particle size of Ni powder is 45 - 60μm; Prepare the mixed powder into a slurry, and then prepare it into a mixed powder by spray granulation.

4. The preparation method of a special bulletproof ceramic according to claim 1, characterized in that, The coating material of the columnar coating is Al2O3, SiC or TiBN, and the coating thickness is 200 - 300μm.

5. The preparation method of a special bulletproof ceramic according to claim 1, characterized in that, The process parameters of vacuum heat treatment are: temperature is 500°C, and the holding time is 8h.

6. The preparation method of a special bulletproof ceramic according to claim 1, characterized in that, The process parameters of the electron beam physical vapor deposition method are: deposition rate is 2 - 3μm / min, the ratio of substrate temperature to target material melting point is 0.3 - 0.5, the vacuum degree is 6 - 8Pa, and the electron beam current intensity is 1 - 2A.

7. The preparation method of a special bulletproof ceramic according to claim 1, characterized in that, The process parameters of the supersonic flame spraying method are: the flow rate of fuel gas C2H2 is 20 - 25L / min, the oxygen flow rate is 200 - 230L / min, and the spraying distance is 200 - 300mm.

8. The preparation method of a special anti - ballistic ceramic according to claim 1, characterized in that, The metal transition layer is a Ti transition layer.

9. A special bulletproof ceramic, characterized in that, Prepared by using the preparation method of a special bulletproof ceramic according to any one of claims 1 to 8.

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