Multi-layer brazing aluminum oxide ceramic bulletproof plugboard and preparation method thereof

Abstract

The invention belongs to the technical field of ceramic bulletproof flashboards, and discloses a multi-layer brazed alumina ceramic bulletproof flashboard and a preparation method thereof, the multi-layer brazed alumina ceramic bulletproof flashboard is formed by bonding a multi-layer alumina ceramic board and an ultra-high molecular weight polyethylene (UHMWPE) fiber woven backboard through an epoxy resin adhesive; according to the multilayer aluminum oxide ceramic plate, aluminum oxide ceramic pieces are connected through Ag-Cu-Ti brazing filler metal through a vacuum brazing process, and brazing layers are formed between the aluminum oxide ceramic layers. The metal brazing layer in the multi-layer brazing aluminum oxide ceramic plate has high fracture toughness, when a bullet intrudes into the bulletproof plate, a crack arrest layer can be formed, brittle fracture of high-hardness aluminum oxide ceramic is reduced, and therefore the bullet intruding depth is increased, and light weight of the bulletproof inserting plate is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic bulletproof insert plates, and in particular, relates to a multi-layer brazed alumina ceramic bulletproof insert plate and a preparation method thereof. Background Art

[0002] Alumina ceramics have the advantages of high hardness, high elastic modulus, high compression strength, and low preparation cost. Alumina ceramics are widely used in the field of bulletproof inserts. Traditional alumina ceramic bulletproof plates are single-layer alumina ceramic structures. Due to the low fracture toughness of alumina ceramics, when bullets invade alumina ceramic bulletproof armor, they are prone to brittle fracture, resulting in low bulletproof performance. Increasing the thickness of alumina ceramics can improve the bulletproof performance, but increasing the thickness will increase the weight of the bulletproof insert, increase the burden of individual combat, reduce the flexibility of individual combat, and make it difficult to meet the needs of modern militarized combat. Metal materials have high strength and high toughness. However, metal materials have low hardness and low elastic modulus, and their ability to prevent bullet invasion is poor. Alumina ceramics and metal materials are made into a simple stacked structure. Since there is no bonding strength at the interface between alumina ceramics and metal materials, the bullet invasion causes the first layer of alumina ceramics to directly penetrate the metal layer and invade the next layer of alumina ceramics, which has no substantial effect on improving the bulletproof effect. Therefore, on the premise of meeting the bulletproof performance of alumina ceramic bulletproof inserts, it is an urgent problem to achieve lightweight bulletproof inserts. Summary of the invention

[0003] In order to solve the above-mentioned deficiencies in the prior art, the present invention aims to provide a multi-layer brazed alumina bullet-proof insert.

[0004] Another object of the present invention is to provide a method for preparing the above-mentioned multi-layer brazed alumina bulletproof insert. The method uses Ag-Cu-Ti as brazing material, prepares alumina ceramic into a multi-layer structure through a brazing process, and vacuum brazes and bonds a UHMWPE fiber woven backing plate to achieve a lightweight alumina ceramic bulletproof insert with high anti-ballistic performance.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A multi-layer brazed alumina ceramic bulletproof insert is formed by bonding a multi-layer alumina ceramic plate and a UHMWPE fiber woven backing plate by epoxy resin adhesive; the multi-layer alumina ceramic plate is formed by connecting alumina ceramic sheets with Ag-Cu-Ti brazing material by vacuum brazing process to form a brazing layer between alumina ceramic layers.

[0007] Preferably, the alumina content in the alumina ceramic sheet is higher than 99%; the thickness of the alumina ceramic sheet is 2.5-5 mm, the number of layers of the alumina ceramic sheet is 2-4, the thickness of the brazing layer is 10-30 μm, and the thickness of the UHMWPE fiber woven backing plate is 5-10 mm.

[0008] Preferably, the particle sizes of Ag, Cu and Ti in the Ag-Cu-Ti solder are all 0.5-5 μm, and the mass ratio of Ag, Cu and Ti is (60-80):(15-38):(2-5).

[0009] The method for preparing the multi-layer brazed alumina ceramic bulletproof insert comprises the following specific steps:

[0010] S1. Ag, Cu and Ti were mixed and added with ethanol, ethyl cellulose and pinene alcohol and ball-milled to obtain Ag-Cu-Ti slurry;

[0011] S2. Ag-Cu-Ti slurry is applied to the surface of alumina ceramic sheets by screen printing, the alumina ceramic sheets are stacked, a pressure of 1 to 5 MPa is applied, and the alumina ceramic sheets and Ag-Cu-Ti slurry are placed in a vacuum brazing furnace at a vacuum degree of 1 to 5×10 -4 Pa and 900-1100°C for 10-30 min to form a brazing layer between the alumina layers to obtain a multi-layer alumina ceramic plate;

[0012] S3. The multi-layer alumina ceramic plate and the UHMWPE fiber woven back plate are bonded with epoxy resin to prepare a multi-layer brazed alumina ceramic bullet-proof insert.

[0013] Preferably, the ball milling speed in step S1 is 100-500 r / min, and the ball milling time is 6-24 h.

[0014] Preferably, the brazing connection time in step S2 is 10 to 30 minutes.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The multi-layer brazed alumina ceramic bullet-proof insert of the present invention can effectively improve the bending strength of the multi-layer alumina ceramic bullet-proof layer under the premise of equal thickness.

[0017] 2. The present invention forms a metal Ag-Cu-Ti brazing layer with high bonding strength in the gaps between multiple layers of alumina ceramics through alumina vacuum brazing. The brazing layer can effectively improve the crack expansion caused by brittle fracture of alumina ceramics when bullets invade, thereby reducing the invasion depth of bullets. Compared with traditional bulletproof plates, under the same bulletproof level, the thickness of the alumina ceramic bulletproof layer can be reduced to achieve lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the multi-layer brazed alumina bullet-proof insert plate of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in further detail below in conjunction with examples, but embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0020] Example 1

[0021] 1. Place 77wt% Ag (particle size of 1μm), 20wt% Cu (particle size of 1μm) and 3wt% Ti (particle size of 1μm) in a nylon ball mill, add ethanol, ethyl cellulose and pinene alcohol, and ball mill the mixture on a planetary ball mill (speed of 250r / min) for 12h to obtain Ag-Cu-Ti slurry.

[0022] 2. Ag-Cu-Ti slurry was applied to the surface of alumina ceramic sheet (alumina content was higher than 99%) by screen printing, and the slurry coating thickness was 40 μm. Two alumina ceramic sheets with a thickness of 3.5 mm were stacked together in a fixed mold, and a pressure of 5 MPa was applied. The alumina ceramic sheet and Ag-Cu-Ti slurry were placed in a vacuum brazing furnace at a vacuum degree of 5×10 -4 Pa and 1000 ℃ brazing connection for 20min, forming a brazing layer (thickness of 10-30μm) between the alumina ceramic layers to obtain a multi-layer alumina ceramic plate.

[0023] 3. The multi-layer alumina ceramic plate and the UHMWPE fiber woven back plate (thickness 10 mm) are bonded together by epoxy resin to prepare a multi-layer brazed alumina ceramic bulletproof insert, the structure of which is as follows: Figure 1 shown.

[0024] Example 2

[0025] 1. Place 77wt% Ag (particle size of 1μm), 20wt% Cu (particle size of 1μm) and 3wt% Ti (particle size of 1μm) in a nylon ball mill, add ethanol, ethyl cellulose and pinene alcohol, and ball mill the mixture on a planetary ball mill (speed of 250r / min) for 12h to obtain Ag-Cu-Ti slurry.

[0026] 2. Ag-Cu-Ti slurry was applied to the surface of alumina ceramic sheet by screen printing, and the slurry coating thickness was 40 μm. Three alumina ceramic sheets with a thickness of 2.5 mm were stacked together in a fixed mold and a pressure of 5 MPa was applied. The alumina ceramic sheet and Ag-Cu-Ti slurry were placed in a vacuum brazing furnace at a vacuum degree of 5×10 -4 Pa and 1000 ℃ brazing connection for 20min, forming a brazing layer (thickness of 10-30μm) between the alumina ceramic layers to obtain a multi-layer alumina ceramic plate.

[0027] 3. The multi-layer alumina ceramic plate and the UHMWPE fiber woven back plate (thickness 10 mm) are bonded together by epoxy resin to prepare a multi-layer brazed alumina ceramic bulletproof insert, the structure of which is as follows: Figure 1 shown.

[0028] Table 1 shows the performance parameters of the multilayer brazed alumina ceramic bulletproof plug plate prepared in Example 1-2. As can be seen from Table 1, with reference to the GA 141-2020 standard, the weight of the GA6-grade single-layer alumina ceramic bulletproof plug plate on the market is 2.7 ± 0.1 Kg, the thickness of the alumina ceramic plate is 8 mm, and the bending strength of the alumina ceramic plate is 370 ± 35 MPa. The thickness of the multilayer brazed alumina ceramic in the multilayer brazed alumina bulletproof plug plate of Example 1 is 7 mm, the bending strength of the multilayer alumina ceramic plate is 410 ± 27 MPa, the weight of the bulletproof plug plate is 2.4 ± 0.1 Kg, and the bulletproof grade is GA6. The thickness of the multilayer brazed alumina ceramic in the multilayer brazed alumina bulletproof plug plate prepared in Example 2 is 7.5 mm, the bending strength of the multilayer alumina ceramic plate is 450 ± 23 MPa, the weight of the bulletproof plug plate is 2.5 ± 0.1 Kg, and the bulletproof grade is GA6. It can be seen that under the same bulletproof grade conditions, the bending strength of the multi-layer brazed alumina ceramic bulletproof plug plate prepared by the present invention is 383-437 MPa, and the weight of the bulletproof plug plate is 2.3-2.6 Kg, which can effectively improve the bending strength of the alumina ceramic plate, reduce the weight, and achieve lightweight.

[0029] Table 1 Performance parameters of multi-layer brazed alumina ceramic bulletproof inserts prepared in Example 1 and Example 2

[0030]

[0031] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A multi-layer brazed alumina ceramic bulletproof insert, characterized in that: The multi-layer brazed alumina ceramic bulletproof insert is formed by bonding a multi-layer alumina ceramic plate and a UHMWPE fiber woven back plate by epoxy resin adhesive; the multi-layer alumina ceramic plate is formed by connecting alumina ceramic sheets with Ag-Cu-Ti brazing material by vacuum brazing process to form a brazing layer between alumina ceramic layers.

2. The multi-layer brazed alumina ceramic bulletproof insert according to claim 1, characterized in that: The alumina content in the alumina ceramic sheet is higher than 99%; the thickness of the alumina ceramic sheet is 2.5 to 5 mm, the number of layers of the alumina ceramic sheet is 2 to 4, the thickness of the brazing layer is 10 to 30 μm, and the thickness of the UHMWPE fiber woven backing plate is 5 to 10 mm.

3. The multi-layer brazed alumina ceramic bulletproof insert according to claim 1, characterized in that: The particle sizes of Ag, Cu and Ti in the Ag-Cu-Ti solder are all 0.5-5 μm, and the mass ratio of Ag, Cu and Ti is (60-80):(15-38):(2-5).

4. The method for preparing the multi-layer brazed alumina ceramic bulletproof insert according to any one of claims 1 to 3, characterized in that: The specific steps include: S1. Ag, Cu and Ti were mixed and added with ethanol, ethyl cellulose and pinene alcohol and ball-milled to obtain Ag-Cu-Ti slurry; S2. Ag-Cu-Ti slurry is applied to the surface of alumina ceramic sheets by screen printing, the alumina ceramic sheets are stacked, a pressure of 1 to 5 MPa is applied, and the alumina ceramic sheets and Ag-Cu-Ti slurry are combined in a vacuum of 1 to 5×10 -4 Pa and 900-1100°C for brazing connection, forming a brazing layer between the alumina layers to obtain a multi-layer alumina ceramic plate; S3. The multi-layer alumina ceramic plate and the UHMWPE fiber woven backing plate are bonded with epoxy resin to prepare a multi-layer brazed alumina ceramic bulletproof insert.

5. The method for preparing a multi-layer brazed alumina ceramic bulletproof insert according to claim 4, characterized in that: The ball milling speed in step S1 is 100-500 r / min, and the ball milling time is 6-24 h.

6. The method for preparing a multi-layer brazed alumina ceramic bulletproof insert according to claim 4, characterized in that: The brazing connection time in step S2 is 10 to 30 minutes.

Images