CN115259859B - Boron carbide bulletproof ceramic material and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of bulletproof materials, in particular to a boron carbide bulletproof ceramic material and a preparation method thereof. The bulletproof ceramic material of the present invention is made by vacuum siliconizing a ceramic body; the raw materials of the ceramic body include ceramic main material, reinforced agent and binder; the ceramic main material includes boron carbide particles with three different particle sizes, the particle size of the primary boron carbide particles is 20μm~25μm, the particle size of the secondary boron carbide particles is 1μm~5μm, and the particle size of the third-grade boron carbide particles The particle size of the particles is 50nm-500nm; and the strengthening agent is carbon nanotube, titanium dioxide, aluminum oxide and the like modified by a coupling agent. The invention selects boron carbide particles of different particle levels and adopts a vacuum siliconizing reaction sintering method to prepare the boron carbide bulletproof ceramic material. The sintering temperature is low, the preparation process is simple, and the cost is low, while improving the mechanical properties of the boron carbide bulletproof ceramic material.

Description

A kind of boron carbide bulletproof ceramic material and preparation method thereof

technical field

The invention relates to the technical field of bulletproof materials, in particular to a boron carbide bulletproof ceramic material and a preparation method thereof.

Background technique

With the rapid development of modern science and technology and the national economy, aerospace, military industry, nuclear industry, machinery manufacturing and other fields are also developing continuously, and the performance requirements of various materials are also continuously increasing. Compared with traditional metal materials, ceramic materials stand out in the field of bulletproof armor because of their advantages such as low density, high hardness, high strength, heat resistance and shock resistance, and are widely used in military or civilian special vehicles. Among them, boron carbide (B ₄ C) is an important structural ceramic, because of its low density, ultra-high hardness, high temperature wear resistance, high melting point, chemical corrosion resistance and excellent neutron absorption performance, so it is used as bulletproof The most widely used material is a very important structural ceramic material.

At present, boron carbide ceramic materials are mainly prepared by powder metallurgy methods. Commonly used sintering methods include hot pressing sintering, pressureless sintering, hot isostatic pressing sintering, spark plasma sintering, and reaction sintering. A variety of sintering methods have their own advantages and disadvantages. The hot pressing sintering temperature is high and sintering aids must be added, so the energy consumption is high and the cost is high; the temperature required for pressureless sintering is extremely high; the cost of hot isostatic pressing sintering equipment is high and the sintering size is limited ; Spark plasma sintering equipment is expensive, the process is complicated, the cost is high, and it is not suitable for industrialization. In recent years, the reaction sintering method has gradually received extensive attention and research in the field. The reaction sintering method generally refers to the vacuum infiltration method. At a certain temperature, molten silicon or metal is infiltrated into the green body by means of capillary action, filling the gaps in the green body after the reaction, and forming a dense green body. The reaction sintering method has obvious advantages, such as low sintering temperature, short time consumption, low cost and simple process.

However, the reaction sintering method also has some shortcomings. The mechanical properties of elemental silicon are poor, so the existence of elemental silicon reduces the mechanical properties of ceramic materials to a certain extent. Therefore, how to improve the reaction sintering method to increase the mechanical properties of ceramic materials Mechanical properties are still a research hotspot in the field.

Contents of the invention

(1) Technical problems to be solved

In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a boron carbide bulletproof ceramic material and a preparation method thereof, which prepares a ceramic body by selecting boron carbide particles of different particle sizes, and adopts a vacuum siliconizing reaction sintering method to prepare carbonized The boron bulletproof ceramic material has low sintering temperature, simple preparation process and low cost, and simultaneously improves the mechanical properties of the boron carbide bulletproof ceramic material.

(2) Technical solutions

In order to achieve the above object, the main technical solutions adopted in the present invention include:

In the first aspect, the present invention provides a boron carbide bulletproof ceramic material, the bulletproof ceramic material of the present invention is made by vacuum siliconizing a ceramic body;

The raw materials of the ceramic green body include ceramic main materials, reinforcing agents and binders;

Among them, the ceramic main material includes primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles. The particle size of tertiary boron carbide particles is 50nm~500nm;

Moreover, the reinforcing agent is modified by a coupling agent; the reinforcing agent is one or a combination of carbon nanotubes, titanium dioxide, titanium diboride, titanium carbide, and aluminum oxide.

More preferably, the particle size of the primary boron carbide particles is 25 μm, the particle size of the secondary boron carbide particles is 3 μm, and the particle size of the tertiary boron carbide particles is 300 nm.

More preferably, the binder is phenolic resin.

More preferably, the mass ratio of the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles is 7-10:3-6:3-6.

More preferably, the mass ratio of the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles is 8:4:5.

More preferably, the mass fraction of the reinforcing agent in the ceramic body is 0.5%-2%.

More preferably, the reinforcing agent is 0.5% of carbon nanotubes and 1.5% of titanium dioxide in the total mass of the ceramic body.

More preferably, the coupling agent is one of the silane coupling agents KH550, KH560, and KH570.

In a second aspect, the present invention provides a method for preparing a boron carbide bulletproof ceramic material, which mainly includes the following steps:

S1. Take primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles according to the ratio, dissolve them in a certain amount of deionized water and ultrasonically disperse them, and add them in turn to the dispersed tertiary boron carbide particle dispersion The secondary boron carbide particle dispersion and the primary boron carbide particle dispersion are continuously stirred, and the ceramic main material is obtained after stirring evenly;

S2. Dissolve a certain amount of reinforcing agent and coupling agent in an aqueous ethanol solution for modification, then add the modified reinforcing agent to the main ceramic material, add a binder at the same time, and continue stirring to form a mixed material. After drying, grinding and sieving, the material to be molded is formed;

S3, pressing the above-mentioned material to be molded into shape, and obtaining a ceramic green body after drying;

S4. Taking a silicon block and placing it on the above-mentioned ceramic green body, and performing vacuum siliconizing reaction sintering in a vacuum furnace to obtain a boron carbide bulletproof ceramic material.

More preferably, in step S1, the particle size of the primary boron carbide particles is 20 μm-25 μm, the particle size of the secondary boron carbide particles is 1 μm-5 μm, and the particle size of the tertiary boron carbide particles is 50 nm-500 nm.

More preferably, the reinforcing agent is one or a combination of carbon nanotubes, titanium dioxide, titanium diboride, titanium carbide, and aluminum oxide.

More preferably, the mass ratio of the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles is 7-10:3-6:3-6.

More preferably, the tertiary boron carbide particles are ultrasonically dispersed for 30 to 40 minutes, the secondary boron carbide particles are ultrasonically dispersed for 20 to 30 minutes, and the primary boron carbide particles are ultrasonically dispersed for 5 to 15 minutes.

More preferably, in step S2, the drying temperature is 50-55° C., and the drying time is 10-12 hours.

More preferably, one-way compression molding is adopted in step S3, the pressure is 150MPa-200MPa, and the holding time is 10s-15s.

More preferably, during the vacuum siliconizing reaction sintering process in step S4, the temperature is raised to 1450° C. to 1600° C. at a heating rate of 5 to 10° C./min, and the temperature is kept for 20 to 50 minutes.

(3) Beneficial effects

A boron carbide bulletproof ceramic material and a preparation method thereof of the present invention select boron carbide particles with three particle sizes and reasonably match them to prepare ceramic main materials. During compression molding, the primary boron carbide particles and secondary boron carbide particles are micron-sized boron carbide particles of different sizes, both of which are mainly used as the skeleton of the green body; the tertiary boron carbide particles are nano-sized boron carbide particles, on the one hand small It can fill the pores between the large particle skeletons, make the ceramic bodies tightly packed, and help to form a denser body. On the other hand, nano-sized boron carbide particles can be dispersed between the large grains and the crystals. In the interior of the grain, by inhibiting the abnormal growth of the grain, a more uniform grain is formed and the mechanical properties of the ceramic material are improved.

In addition, the boron carbide bulletproof ceramic material and the preparation method thereof of the present invention, in addition to the ceramic main material, also add a reinforcing agent, the reinforcing agent is selected from one of carbon nanotubes, titanium dioxide, titanium diboride, titanium carbide, and aluminum oxide. or several. The addition of reinforcing agents such as carbon nanotubes and titanium dioxide can effectively improve the fracture toughness of ceramic materials. At the same time, the reinforcing agent in the present invention is modified with a coupling agent, and the modified reinforcing agent can not only achieve more uniform dispersion, but also be easier to combine with the main ceramic material. Further, during the vacuum siliconizing process, the addition of carbon nanotubes can promote the infiltration of silicon, thereby making the ceramic material denser and increasing the hardness of the ceramic material.

Further, the present invention uses phenolic resin as a binder. On the one hand, the phenolic resin can combine the main ceramic material and the reinforcing agent well. On the other hand, the phenolic resin can also provide a carbon source for the vacuum siliconizing process. , due to its better fluidity, it can penetrate into the green body more fully, and the carbon source is more evenly distributed, so that the carbon source can react with silicon more fully, reducing the residual carbon in the final ceramic material, and The formed product silicon carbide is more evenly distributed in the ceramic material, thereby improving the mechanical properties of the ceramic material.

In summary, a boron carbide bulletproof ceramic material of the present invention and its preparation method prepare a ceramic body by selecting boron carbide particles of different particle sizes as the main ceramic material, so that the ceramic body is more compact; and the ceramic body is also added The reinforcing agent is added, which further improves the mechanical properties of the ceramic body; at the same time, the present invention adopts the vacuum siliconizing reaction sintering method to prepare the boron carbide bulletproof ceramic material, and the sintering temperature is low. While ensuring the simple preparation process and low cost, it can also improve Various mechanical properties of boron carbide bulletproof ceramic materials.

detailed description

In order to better understand the above technical solutions, the present invention will be described in detail below through specific implementation modes. It should be understood, however, that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be more clearly and thoroughly understood, and the scope of the present invention can be fully conveyed to those skilled in the art.

An embodiment of the present invention provides a boron carbide bulletproof ceramic material. The bulletproof ceramic material is made of a ceramic body through vacuum siliconization; the raw materials of the ceramic body include ceramic main materials, reinforcing agents and binders; wherein, Ceramic main materials include primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles, the particle size of primary boron carbide particles is 20μm~25μm, the particle size of secondary boron carbide particles is The particle size of boron carbide particles is 50nm~500nm; and the strengthening agent is modified by coupling agent; the strengthening agent is one or more of carbon nanotubes, titanium dioxide, titanium diboride, titanium carbide, and alumina combination, the binder is phenolic resin. In this embodiment, the mass fraction of the reinforcing agent in the ceramic body is 0.5%-2%. More preferably, the particle diameter of the primary boron carbide particles is 25 μm, the particle diameter of the secondary boron carbide particles is 3 μm, and the particle diameter of the tertiary boron carbide particles is 300 nm. In this embodiment, the mass ratio of the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles is 7-10:3-6:3-6. More preferably, the mass ratio of the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles is 8:4:5.

Among the above-mentioned boron carbide bulletproof ceramic materials, three boron carbide particles with different particle sizes were selected, ranging from 20μm~25μm, 1μm~5μm and 50nm~500nm respectively from coarse to fine. Among them, boron carbide particles with larger particle sizes were used as ceramics The skeleton of the green body, and the boron carbide particles of small particle size can not only be filled into the skeleton of the ceramic body to make the ceramic body more compact, but also the nano-sized boron carbide particles can be dispersed between the large grains And inside the grains, it can inhibit the abnormal growth of grains, form more uniform grains, and improve the mechanical properties of ceramic materials. In addition, the boron carbide ceramic particles with larger particle size can also make the reaction with silicon more moderate during the siliconizing process, thereby reducing the generation of high-density SiC, thereby controlling the density of the ceramic material.

However, with the addition of larger boron carbide particles, the hardness of the ceramic material continues to increase, but too much addition will also reduce the strength and toughness of the ceramic material, so it is necessary to further increase the secondary boron carbide particles for regulation, and at the same time , the boron carbide particles of the three particle sizes need to be kept within a reasonable ratio range to make the ceramic material have a certain hardness and increase the density. In addition, in order to make up for the problem that the toughness of the ceramic material decreases during the preparation process, this example adds carbon nanotubes, titanium dioxide, titanium carbide, alumina, etc. as reinforcing agents, and the reinforcing agent is modified with a silane coupling agent. The final reinforcing agent improves the binding ability with the ceramic main material, and improves the dispersion, making it more uniformly dispersed. Among them, the addition of an appropriate amount of carbon nanotubes can not only effectively improve the fracture toughness of the ceramic material, but also promote The infiltration of silicon further increases the density of the ceramic material and improves the mechanical properties of the ceramic material.

Another embodiment of the present invention provides a method for preparing a boron carbide bulletproof ceramic material, which mainly includes the following steps:

S1. Take primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles according to the ratio, dissolve them in a certain amount of deionized water and then ultrasonically disperse them. Among them, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 7~10:3~6:3~6, and the particle size of primary boron carbide particles is 20μm~25μm, The particle size of the secondary boron carbide particles is 1 μm to 5 μm, and the particle size of the tertiary boron carbide particles is 50 nm to 500 nm. Then, the secondary boron carbide particle dispersion and the primary boron carbide particle dispersion are sequentially added to the dispersed tertiary boron carbide particle dispersion, continuously stirred, and the ceramic main material is obtained after stirring evenly. In this example, according to the different particle sizes of the three kinds of boron carbide particles, the three kinds of particle-grade boron carbides were ultrasonically dispersed, and different ultrasonic dispersion times were set. Grade boron carbide particles are ultrasonically dispersed for 20~30min, and primary boron carbide particles are ultrasonically dispersed for 5~15min. It can ensure that the boron carbide of three particle levels can be uniformly dispersed, and the preparation efficiency is also improved.

S2. Dissolve 0.5% to 2% of the reinforcing agent and 0.1% to 0.3% of the silane coupling agent in the total mass of the ceramic body in an aqueous ethanol solution for modification. In this embodiment, the reinforcing agent can be carbon nanotubes, titanium dioxide , titanium diboride, titanium carbide, aluminum oxide or a combination of several. Then the modified reinforcing agent is added to the ceramic main material that is constantly stirring, and a binder is added at the same time. The binder in this embodiment is phenolic resin, and the quality of carbon in the phenolic resin is three kinds of particle-level carbonization 8-10% of the total mass of boron particles, continuously stirred for 8-10 hours, after forming the mixed material, the material to be molded was formed through drying, grinding, and sieving. In this embodiment, an oven was used for drying, and the drying temperature was 50 -55℃, drying time 10-12 hours.

S3. Pressing and molding the above-mentioned materials to be molded, and drying to obtain a ceramic green body. In this embodiment, one-way compression molding is adopted, the pressure is 150MPa~200MPa, and the holding time is 10s~15s.

S4. Taking a silicon block and placing it on the above-mentioned ceramic green body, and performing vacuum siliconizing reaction sintering in a vacuum furnace to obtain a boron carbide bulletproof ceramic material. In the process of vacuum siliconizing in this example, the temperature is first raised to 1450°C~1600°C at a heating rate of 5~10°C/min, then kept for 20~50min, then cooled to room temperature, and the infiltration is completed, and boron carbide is obtained. Bulletproof ceramic material.

Example 1

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (25 μm) and add appropriate amount of deionized water, ultrasonically disperse for 5 minutes, take secondary boron carbide particles (3 μm) and add appropriate amount of deionized water, ultrasonically disperse for 25 minutes, take tertiary boron carbide particles (300nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 8:4:5. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 0.5% carbon nanotubes, 1.5% titanium dioxide powder and 0.3% silane coupling agent of the total mass of the ceramic body and dissolve them in an aqueous ethanol solution for modification, and then add the modified carbon nanotubes and titanium dioxide powder Add a certain amount of phenolic resin to the ceramic main material that is constantly stirring, so that the amount of carbon in the phenolic resin is 10% of the total mass of the three particle-grade boron carbides, and continue to stir for 9 hours, then place the obtained mixture in Dry in an oven at a drying temperature of 50°C for 12 hours, grind, and then pass through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 50° C., and obtain a ceramic green body after drying for 12 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1500°C at a heating rate of 5°C/min, then keep it warm for 30min, then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Example 2

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (25 μm) and add appropriate amount of deionized water, ultrasonically disperse for 5 minutes, take secondary boron carbide particles (3 μm) and add appropriate amount of deionized water, ultrasonically disperse for 25 minutes, take tertiary boron carbide particles (300nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 9:5:5. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 0.5% carbon nanotubes, 1.5% titanium dioxide powder and 0.3% silane coupling agent of the total mass of the ceramic body and dissolve them in an aqueous ethanol solution for modification, and then add the modified carbon nanotubes and titanium dioxide powder Add a certain amount of phenolic resin to the ceramic main material that is constantly stirring, so that the amount of carbon in the phenolic resin is 10% of the total mass of the three particle-grade boron carbides, and continue to stir for 9 hours, then place the obtained mixture in Dry in an oven at a drying temperature of 50°C for 12 hours, grind, and then pass through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 50° C., and obtain a ceramic green body after drying for 12 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1500°C at a heating rate of 5°C/min, then keep it warm for 30min, then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Example 3

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (25 μm) and add appropriate amount of deionized water, ultrasonically disperse for 5 minutes, take secondary boron carbide particles (3 μm) and add appropriate amount of deionized water, ultrasonically disperse for 25 minutes, take tertiary boron carbide particles (300nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 7:4:6. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 0.8% carbon nanotubes, 1% titanium dioxide powder and 0.2% silane coupling agent of the total mass of the ceramic body and dissolve them in an aqueous ethanol solution for modification, and then add the modified carbon nanotubes and titanium dioxide powder Add a certain amount of phenolic resin to the ceramic main material that is constantly stirring, so that the amount of carbon in the phenolic resin is 10% of the total mass of the three particle-grade boron carbides, and continue to stir for 9 hours, then place the obtained mixture in Dry in an oven at a drying temperature of 50°C for 12 hours, grind, and then pass through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 50° C., and obtain a ceramic green body after drying for 12 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1500°C at a heating rate of 5°C/min, then keep it warm for 30min, then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Example 4

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (20μm) and add appropriate amount of deionized water, ultrasonically disperse for 10min, take secondary boron carbide particles (5μm) and add appropriate amount of deionized water, ultrasonically disperse for 25min, take tertiary boron carbide particles (500nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 8:4:5. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 0.5% carbon nanotubes, 1.5% titanium dioxide powder and 0.3% silane coupling agent of the total mass of the ceramic body and dissolve them in an aqueous ethanol solution for modification, and then add the modified carbon nanotubes and titanium dioxide powder Add a certain amount of phenolic resin to the ceramic main material that is constantly stirring, so that the amount of carbon in the phenolic resin is 10% of the total mass of the three particle-grade boron carbides, and continue to stir for 9 hours, then place the obtained mixture in Dry in an oven at a drying temperature of 50°C for 12 hours, grind, and then pass through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 50° C., and obtain a ceramic green body after drying for 12 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1500°C at a heating rate of 5°C/min, then keep it warm for 30min, then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Example 5

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (25 μm) and add appropriate amount of deionized water, ultrasonically disperse for 5 minutes, take secondary boron carbide particles (3 μm) and add appropriate amount of deionized water, ultrasonically disperse for 25 minutes, take tertiary boron carbide particles (300nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 8:4:5. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 1% carbon nanotubes and 0.2% silane coupling agent of the total mass of the ceramic body and dissolve them in an aqueous ethanol solution for modification, and then add the modified carbon nanotubes to the ceramic main material that is constantly stirred, Then add a certain amount of phenolic resin, so that the amount of carbon in the phenolic resin is 8% of the total mass of the three particle-grade boron carbides, continue to stir for 9 hours, then place the obtained mixed material in an oven to dry, and the drying temperature is 55 ℃, dried for 10 hours, ground, and then passed through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 55° C., and obtain a ceramic green body after drying for 10 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1550°C at a heating rate of 6°C/min, then keep it warm for 20 minutes, and then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Example 6

This embodiment provides a method for preparing a boron carbide bulletproof ceramic material, comprising the following steps:

S1. Take primary boron carbide particles (25 μm) and add appropriate amount of deionized water, ultrasonically disperse for 5 minutes, take secondary boron carbide particles (3 μm) and add appropriate amount of deionized water, ultrasonically disperse for 25 minutes, take tertiary boron carbide particles (300nm) and add Appropriate amount of deionized water, ultrasonic dispersion for 30 minutes, the mass ratio of primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles is 8:4:5. After dispersing, in the process of continuous stirring, firstly add the secondary boron carbide particle dispersion liquid to the tertiary boron carbide particle dispersion liquid, and then add the primary boron carbide particle dispersion liquid to obtain the ceramic main material.

S2. Take 2% alumina powder and 0.2% silane coupling agent of the total mass of the ceramic body and dissolve it in an aqueous ethanol solution for modification, then add the modified alumina powder to the ceramic main material that is constantly stirred, Then add a certain amount of phenolic resin, so that the amount of carbon in the phenolic resin is 8% of the total mass of the three particle-grade boron carbides, continue to stir for 9 hours, then place the obtained mixed material in an oven to dry, and the drying temperature is 55 ℃, dried for 10 hours, ground, and then passed through a 50-mesh sieve to form a material to be molded.

S3. The above-mentioned material to be molded is unidirectionally molded at a pressure of 150 MPa, and the pressure is maintained for 15 seconds. Then place it in an oven for drying at a temperature of 55° C., and obtain a ceramic green body after drying for 10 hours.

S4. Take a silicon block and place it on the above-mentioned ceramic body, and carry out vacuum silicon infiltration reaction sintering in a vacuum furnace. First, heat up to 1550°C at a heating rate of 6°C/min, then keep it warm for 20 minutes, and then cool to room temperature, and infiltrate At the end, the boron carbide bulletproof ceramic material is obtained.

Comparative example 1

This example is based on the change of conditions in Example 1. The difference from Example 1 is that in this example, primary boron carbide particles (25 μm), secondary boron carbide particles (3 μm) and tertiary boron carbide particles (300nm ) with a mass ratio of 12:5:2, and the rest of the process and conditions remain unchanged, and a boron carbide bulletproof ceramic material is obtained.

Comparative example 2

This example changes the conditions on the basis of Example 1. The difference from Example 1 is that this example only contains micron-sized boron carbide particles, that is, only primary boron carbide particles (25 μm) and secondary boron carbide particles (3μm), the rest of the process and conditions are unchanged, and the boron carbide bulletproof ceramic material is prepared.

Comparative example 3

This example changes conditions on the basis of Example 1. The difference from Example 1 is that the boron carbides of three particle sizes in this example have not undergone the pre-ultrasonic dispersion process, specifically:

S1. Take primary boron carbide particles (25μm), secondary boron carbide particles (3μm), and tertiary boron carbide particles (300nm) at a mass ratio of 8:4:5 and add them to a certain amount of deionized water, and ultrasonically disperse them for 20 minutes. Then carry out mechanical stirring to obtain the ceramic main material.

The rest of the process and conditions are unchanged, and the boron carbide bulletproof ceramic material is obtained.

Comparative example 4

This example is carried out the change of conditions on the basis of Example 1, and the difference from Example 1 is that the reinforcing agent accounts for 3.5% of the mass fraction of the ceramic green body, wherein 1% of carbon nanotubes, 2.5% of titanium dioxide powder, the rest of the process and The conditions are all the same, and the boron carbide bulletproof ceramic material is prepared.

Performance tests were performed on Examples 1 to 6 and Comparative Examples 1 to 4, and the results are shown in Table 1.

Table 1 Performance test results of boron carbide bulletproof ceramic materials

It can be seen from the above results that the boron carbide bulletproof ceramic materials prepared in Examples 1 to 6 all have high Vickers hardness, fracture toughness and bending strength, and the overall mechanical properties are high and excellent. And the various performances of the boron carbide bulletproof ceramic material that comparative example 1 to comparative example 4 make are slightly worse, and the result proves, the boron carbide mass ratio of three kinds of grain grades is changed, and the boron carbide of too much larger particle size is added Particles, reduce the amount of nano-sized boron carbide particles, although the ceramic material still has a high hardness, but the fracture toughness is significantly reduced; and the mechanical properties of the ceramic material without adding nano-sized boron carbide particles are significantly reduced, so The addition of a certain amount of nano-sized boron carbide particles can increase the compactness of ceramic materials and improve the mechanical properties of ceramic materials.

In addition, it can also be seen from Comparative Example 3 that the ultrasonic dispersion of the three particle-sized boron carbides is helpful for uniform mixing, so that a more uniform and dense ceramic material can be formed in the subsequent preparation process. It can be seen from Comparative Example 4 that although adding too much reinforcing agent improves the fracture toughness and flexural strength of the ceramic material, the hardness of the ceramic material is significantly reduced, because the hardness of the reinforcing agent itself is lower than that of boron carbide. Therefore, the amount of reinforcing agent needs to be controlled within a certain range to ensure that the ceramic material has appropriate hardness, fracture toughness and flexural strength.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (3)

1. A preparation method of a boron carbide bulletproof ceramic material is characterized by comprising the following steps:

s1, taking primary boron carbide particles, secondary boron carbide particles and tertiary boron carbide particles according to a ratio, respectively dissolving the primary boron carbide particles, the secondary boron carbide particles and the tertiary boron carbide particles in a certain amount of deionized water, then carrying out ultrasonic dispersion, sequentially adding a secondary boron carbide particle dispersion liquid and a primary boron carbide particle dispersion liquid into the dispersed tertiary boron carbide particle dispersion liquid, continuously stirring, and uniformly stirring to obtain a ceramic main material;

the three-level boron carbide particles are subjected to ultrasonic dispersion for 30 to 40min, the two-level boron carbide particles are subjected to ultrasonic dispersion for 20 to 30min, and the first-level boron carbide particles are subjected to ultrasonic dispersion for 5 to 15min;

the particle size of the primary boron carbide particles is 20-25 mu m, the particle size of the secondary boron carbide particles is 1~5 mu m, and the particle size of the tertiary boron carbide particles is 50-500nm;

the mass ratio of the primary boron carbide particles to the secondary boron carbide particles to the tertiary boron carbide particles is 7 to 10:3~6:3~6;

s2, dissolving a certain amount of reinforcing agent and coupling agent in an ethanol aqueous solution for modification, then adding the modified reinforcing agent into the ceramic main material, adding a binder, continuously stirring to form a mixed material, and then drying, grinding and sieving to form a material to be molded;

the reinforcing agent is one or a combination of more of carbon nano tube, titanium dioxide, titanium diboride, titanium carbide and aluminum oxide;

s3, pressing and forming the material to be molded, and drying to obtain a ceramic blank; the reinforcing agent accounts for 0.5-2% of the mass of the ceramic body;

and S4, placing the silicon block on the ceramic blank, and performing vacuum siliconizing reaction sintering in a vacuum furnace to obtain the boron carbide bulletproof ceramic material.

2. The preparation method of the boron carbide bulletproof ceramic material according to claim 1, wherein in the step S3, unidirectional compression molding is adopted, the pressure is 150MPa to 200MPa, and the pressure maintaining time is 10s to 15s.

3. The preparation method of the boron carbide bulletproof ceramic material according to claim 1, wherein in the vacuum siliconizing reaction sintering process in the step S4, the temperature is raised to 1450-1600 ℃ at a temperature raising speed of 5-10 ℃/min, and the temperature is kept for 20-50min.