Preparation method of bulletproof ceramic

Abstract

The invention relates to the field of bulletproof ceramic preparation, in particular to a bulletproof ceramic preparation method which comprises the following steps: determining a structural characteristic state of a green body according to a thickness uniform value and a curvature reference value so as to determine a setting mode of a humidity detection point; determining the states of the detection points according to the positions of the residual detection points, and further determining different adjustment modes; determining the grain type according to the grain size range of the grain size; an adjusting mode is determined according to reference values of the number of different types of crystal grains, the heat preservation time of the second stage is adjusted, or the sintering temperature of the second stage is adjusted, or the heating rate of the first stage is adjusted, or the content of a sintering aid is adjusted; in the first dense reference state, the temperature rise rate of the first stage is adjusted or the sintering temperature of the second stage is adjusted. Parameters in the preparation process can be optimized according to the quality of a sintered product and the quality of a green body.

Description

Technical Field

[0001] The invention relates to the field of bulletproof ceramic preparation, and in particular to a method for preparing bulletproof ceramic. Background Art

[0002] With the application of advanced technology in military warfare, the loss of personnel and property is becoming more and more serious. In order to improve battlefield survivability, the requirements for weapon armor protection are getting higher and higher. Therefore, the research and application of bulletproof materials are particularly important. Due to the characteristics of high strength and hardness, strong wear and corrosion resistance, small thermal expansion coefficient, and simple manufacturing process, ceramic materials have become a research hotspot in the field of bulletproof materials in recent years. However, due to the diversity of bulletproof ceramic materials, in the process of green body drying and sintering products in a pressureless sintering furnace, they are often prepared only according to set fixed parameters, resulting in unsatisfactory preparation effects. Therefore, how to optimize the parameters in the preparation process according to the quality of the sintered finished product and the quality of the green body is a problem that technicians in this field need to solve urgently.

[0003] Chinese patent publication number CN118005404A discloses a silicon carbide bulletproof ceramic and a preparation method thereof, comprising the following raw materials by weight: 80 parts of α-SiC powder, 20-30 parts of boron carbide powder, 0.8-1 parts of a first dispersant, 0.5-0.8 parts of a second dispersant, 10-18 parts of an organic additive, and 0.5-2 parts of a sintering aid. It is made by powder dispersion, batching, water-based spray granulation, dry pressing, secondary densification pressing, shrinkage sintering and pressureless sintering processes. By adopting secondary densification pressing and shrinkage sintering processes, the ceramic blank is densified multiple times to improve the ability of the particles to be tightly bound, and give full play to the role of the reinforcing phase boron carbide to improve the toughness and strength properties of silicon carbide ceramics. However, the above scheme has the following problems: it is impossible to adjust the preparation parameters accordingly according to the quality of the sintered product and the humidity of the green body, resulting in the bulletproof ceramics prepared by fixed preparation parameters not meeting actual needs.

[0004] Technical content

[0005] To this end, the present invention provides a method for preparing bulletproof ceramics, which is used to overcome the problem that the preparation process is only carried out according to set parameters, and the corresponding parameters in the green body drying process and the sintering product process cannot be adjusted according to the quality of the sintered product and the green body humidity, resulting in the bulletproof ceramics prepared by fixed preparation parameters cannot meet actual needs.

[0006] To achieve the above object, the present invention provides a method for preparing a bulletproof ceramic, comprising:

[0007] Determine the structural characteristic state of the green body according to the uniform thickness value and the curvature reference value, and determine the setting method of the humidity detection point according to the structural characteristic state of the green body;

[0008] Determine the residual detection point according to the moisture reference value, and determine the detection point status according to the position of each residual detection point, and adjust the drying time or drying temperature under different detection point states;

[0009] Determining the grain type of the sintered product according to the grain size range of the sintered product;

[0010] When the normal grain quantity reference value is less than the first preset quantity reference value, the adjustment method is determined according to the first-class grain quantity reference value and the second-class grain quantity reference value of the sintered finished product as the first adjustment method for adjusting the holding time of the second stage, or the second adjustment method for adjusting the sintering temperature of the second stage, or the third adjustment method for adjusting the heating rate of the first stage or adjusting the content of the sintering aid;

[0011] The density reference state of the sintered product is determined according to the porosity of the sintered product. Under the first density reference state, the heating rate of the first stage or the sintering temperature of the second stage is adjusted. When it reaches the second density reference state, the sintered product is considered qualified and no adjustment is performed.

[0012] Furthermore, the setting mode of the humidity detection points is determined according to the structural characteristic state of the green body, and the setting mode of the humidity detection points includes a conventional setting mode and a special setting mode.

[0013] Further, the structural characteristic state of the green body is determined according to the uniform thickness value and the curvature reference value, and the structural characteristic state of the green body includes a first structural characteristic state in which the uniform thickness value is less than or equal to a preset uniform thickness value and the curvature reference value is less than or equal to a preset curvature reference value, and a second structural characteristic state in which the uniform thickness value is greater than the preset uniform thickness value or the curvature reference value is greater than the preset curvature reference value.

[0014] Furthermore, the conventional arrangement is to divide the green body into a plurality of regions of equal area, and to set a humidity detection point at the center of each region;

[0015] The special setting method is to divide the green body into several areas of equal area, set a humidity detection point at the center of each area, and increase the number of humidity detection points in areas with possibly higher humidity, such as depressions, protrusions, corners, etc.

[0016] Further, the detection point state is determined according to the position of each residual detection point. If the detection point state is a dense state, the drying time is increased and adjusted. If the detection point state is a discrete state, the drying temperature is increased and adjusted.

[0017] The increase in the drying time is negatively correlated with the maximum moisture reference value corresponding to the residual detection point;

[0018] The increase value of the drying temperature is negatively correlated with the maximum moisture reference value corresponding to the residual detection point;

[0019] The humidity detection point where the moisture reference value is greater than the preset moisture reference value is recorded as a residual detection point.

[0020] Furthermore, the grain type of the sintered product is determined based on the grain size range of the grain size of the sintered product. The grain type of the sintered product includes a type of grains whose grain size of the sintered product is within a first preset grain size range, and a type of grains whose grain size of the sintered product is within a second preset grain size range.

[0021] Further, when the normal grain quantity reference value is less than the first preset quantity reference value, the adjustment method is determined according to the first type grain quantity reference value and the second type grain quantity reference value of the sintered finished product;

[0022] When the reference value of the number of one type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the first adjustment method of increasing the holding time of the second stage;

[0023] When the reference value of the number of the second type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the second adjustment method of reducing the sintering temperature in the second stage;

[0024] When the reference value of the number of the first type of grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of the second type of grains is greater than or equal to the third preset reference value, the adjustment mode is the third adjustment mode;

[0025] The increase in the holding time in the second stage is positively correlated with the grain size of the sintered product;

[0026] The decrease in the sintering temperature in the second stage is positively correlated with the grain size of the sintered product.

[0027] Further, under the first preset condition, when the reference value of the number of the first type of grains in the sintered product is greater than the reference value of the number of the second type of grains, the third adjustment method is to reduce the heating rate of the first stage;

[0028] When the reference value of the number of the first type of grains in the sintered product is less than the reference value of the number of the second type of grains, the third adjustment method is to reduce the content of the sintering aid;

[0029] The decrease in the heating rate in the first stage is positively correlated with the uniformity of the grain size of the sintered product;

[0030] The reduction value of the sintering aid content is positively correlated with the uniformity of the grain size of the sintered product;

[0031] The first preset condition is when the reference value of the number of type one grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of type two grains is greater than or equal to the third preset reference value.

[0032] Further, determining a dense reference state of the sintered product according to the porosity of the sintered product;

[0033] When the dense reference state is a first dense reference state in which the porosity of the sintered product is greater than a preset porosity, the heating rate of the first stage is adjusted to decrease, or the sintering temperature of the second stage is adjusted to increase;

[0034] When the dense reference state is a second dense reference state in which the porosity of the sintered product is less than or equal to the preset porosity, the sintered product is considered qualified and no adjustment is performed;

[0035] The decrease value of the heating rate in the first stage is positively correlated with the density reference value of the sintered product;

[0036] The increase in the sintering temperature in the second stage is positively correlated with the density reference value of the sintered product.

[0037] Furthermore, the product firing process includes three stages: the first stage is the temperature increase process of the sintering device; the second stage is to maintain the sintering temperature for operation; and the third stage is the cooling process.

[0038] Compared with the prior art, the beneficial effect of the present invention lies in that the structural characteristic state of the green body is determined according to the uniform thickness value and the curvature reference value, the structural characteristics of the current green body are effectively reflected through the structural characteristic state of the green body, and different humidity detection point setting methods are selected according to the dense or discrete distribution of the residual detection points, so that the selection of the humidity detection point setting method is more in line with the actual working scenario, avoiding the problem that the green body with special structure cannot accurately judge the current humidity, thereby improving the accuracy of humidity detection.

[0039] Furthermore, in the technical solution of the present invention, the parameters in the drying process are optimized and adjusted according to the status of the detection points, and different adjustment methods are selected according to different detection point states, so that the selection of the adjustment method is more in line with the actual drying effect, avoiding the problem in the prior art that the preparation process is only prepared according to the set parameters and the preparation parameters cannot be adjusted specifically according to the humidity of the green body, thereby improving the drying effect of the green body in the present invention.

[0040] Furthermore, in the technical solution of the present invention, an adjustment method is determined according to a reference value of the number of Class I grains and a reference value of the number of Class II grains of the sintered finished product to optimize and adjust the parameters in the sintering preparation process. Different adjustment methods are selected by using different reference values ​​of the number of Class I grains and the number of Class II grains. This avoids the problem in the prior art that the preparation process is only carried out according to the set parameters and the preparation parameters cannot be adjusted specifically according to the sintered finished product, thereby improving the preparation effect of the sintered finished product in the present invention.

[0041] Furthermore, in the technical solution of the present invention, the dense reference state of the sintered product is determined according to the porosity of the sintered product. By judging whether the porosity of the sintered product meets the actual requirements, it can be effectively determined whether it is necessary to adjust the heating rate and the holding time of the sintering preparation process, thereby avoiding the problem that the prepared bulletproof ceramics cannot meet the actual application requirements, thereby ensuring the preparation effect of the bulletproof ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the preparation method of the bulletproof ceramic of the present invention;

[0043] Figure 2 It is a flow chart of the method for determining the setting of humidity detection points according to the structural characteristic state of the green body according to the present invention;

[0044] Figure 3 A flow chart of determining the structural characteristic state of a green body according to a uniform thickness value and a curvature reference value in the present invention;

[0045] Figure 4 This is a flow chart of the present invention for determining the adjustment method according to the state of the detection point. DETAILED DESCRIPTION

[0046] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0048] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0049] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] See also Figures 1 to 4 As shown, the present invention provides a method for preparing a bulletproof ceramic, comprising:

[0051] Determine the structural characteristic state of the green body according to the uniform thickness value and the curvature reference value, and determine the setting method of the humidity detection point according to the structural characteristic state of the green body;

[0052] Determine the residual detection point according to the moisture reference value, and determine the detection point status according to the position of each residual detection point, and adjust the drying time or drying temperature under different detection point states;

[0053] Determining the grain type of the sintered product according to the grain size range of the sintered product;

[0054] When the normal grain quantity reference value is less than the first preset quantity reference value, the adjustment method is determined according to the first-class grain quantity reference value and the second-class grain quantity reference value of the sintered finished product as the first adjustment method for adjusting the holding time of the second stage, or the second adjustment method for adjusting the sintering temperature of the second stage, or the third adjustment method for adjusting the heating rate of the first stage or adjusting the content of the sintering aid;

[0055] The density reference state of the sintered product is determined according to the porosity of the sintered product. Under the first density reference state, the heating rate of the first stage or the sintering temperature of the second stage is adjusted. When it reaches the second density reference state, the sintered product is considered qualified and no adjustment is performed.

[0056] The preparation process of the bulletproof ceramic of the present invention comprises:

[0057] (1) Ball milling

[0058] TiB 2 Micro powder, B 4 C micro powder, phenolic resin and sintering aid are weighed according to the mass ratio, and the weighed powder is poured into the ball mill. 4 C ceramic balls were used as grinding balls, and anhydrous ethanol was used as the grinding medium. The powders were milled for 20 min using a vertical rapid ball mill to mix them evenly.

[0059] (2) Drying and granulation

[0060] The ball-milled composite ceramic slurry was poured into a tray and placed in a vacuum drying oven. The temperature of the drying oven was adjusted to 55°C. The ceramic slurry was taken out after drying for 24 hours, and then ground in a mortar, and finally granulated through a 60-mesh standard sieve.

[0061] (3) Molding pre-pressing and cold isostatic pressing

[0062] Weigh an appropriate amount of granulation powder and pour it into the mold. Use unidirectional pressure at a pressure of 30 MPa and maintain the pressure for 5 minutes to obtain a pre-pressed green body. Put the pre-pressed green body into a packaging bag, evacuate and seal it, and then use a cold isostatic press to perform static pressing to obtain the required green body. Put the green body obtained after isostatic pressing into a tray, and place the tray in a vacuum drying oven. The temperature of the drying oven is adjusted to 70°C, and the green body is dried for 12 hours.

[0063] (4) Pressureless sintering

[0064] The dried green body is loaded into a pressureless sintering furnace, and the sintering temperature is measured by an infrared thermometer according to the set sintering process; when the sintering is completed, a sintered product is obtained and cooled with the furnace to room temperature.

[0065] (5) Sample processing

[0066] The sintered products are subjected to mechanical processing such as trimming and grinding to eliminate surface defects and burrs and improve their surface finish and dimensional accuracy.

[0067] The above contents are already known to those skilled in the art and will not be elaborated here.

[0068] Specifically, it is characterized in that the setting mode of the humidity detection points is determined according to the structural characteristic state of the green body, and the setting mode of the humidity detection points includes a conventional setting mode and a special setting mode.

[0069] When the structural characteristic state of the green body is the first structural characteristic state, the setting mode of the humidity detection points is a conventional setting mode;

[0070] When the structural characteristic state of the green body is the second structural characteristic state, the setting mode of the humidity detection points is a special setting mode.

[0071] Specifically, the structural characteristic state of the green body is determined according to the uniform thickness value and the curvature reference value, and the structural characteristic state of the green body includes a first structural characteristic state in which the uniform thickness value is less than or equal to a preset uniform thickness value and the curvature reference value is less than or equal to a preset curvature reference value, and a second structural characteristic state in which the uniform thickness value is greater than the preset uniform thickness value or the curvature reference value is greater than the preset curvature reference value.

[0072] The green body is divided into m adjacent regions with the same surface area, and a point in each region is randomly selected for thickness measurement. The maximum measured thickness is recorded as L1, and the minimum measured thickness is recorded as L2. Then the uniform thickness value = L1-L2. The thickness measurement is performed by directly attaching the ultrasonic probe to the surface of the measured area, and calculating the thickness by measuring the ultrasonic propagation time. This is easy for a person skilled in the art to understand and will not be elaborated here. The green body is placed on a standard plate, and a point in each of the above regions is randomly selected. The height difference between each point and the plate is detected by a dial indicator. The maximum measured height difference is recorded as h1, and the minimum measured thickness is recorded as h2. Then the curvature reference value = h1-h2.

[0073] The user can set the preset uniform thickness value and the preset curvature reference value according to the actual application scenario. The higher the user's demand for the uniformity of the green drying effect, the smaller the preset uniform thickness value and the preset curvature reference value. Provided are the preset uniform thickness value and the preset curvature reference value, the preset uniform thickness value is 1 cm, and the preset curvature reference value is 0.5 cm.

[0074] Specifically, the conventional setting method is to divide the green body into a number of regions with the same area, and set a humidity detection point at the center of each region;

[0075] The special setting method is to divide the green body into several areas of equal area, set a humidity detection point at the center of each area, and increase the number of humidity detection points in areas with possibly higher humidity, such as depressions, protrusions, corners, etc.

[0076] The method for confirming the center position is to find the smallest circumscribed circle of each area, and the center of the circle is the center position.

[0077] Specifically, the detection point state is determined according to the position of each residual detection point. If the detection point state is a dense state, the drying time is increased. If the detection point state is a discrete state, the drying temperature is increased.

[0078] The increase in the drying time is negatively correlated with the maximum moisture reference value corresponding to the residual detection point;

[0079] The increase value of the drying temperature is negatively correlated with the maximum moisture reference value corresponding to the residual detection point;

[0080] The humidity detection point where the moisture reference value is greater than the preset moisture reference value is recorded as a residual detection point.

[0081] The moisture reference value of each detection point is the detection value of the microwave transmission moisture meter. The preset moisture reference value can be set by the user according to the actual situation. It can be understood that the requirements for the dryness of the green body are different in the actual use scenario. The higher the requirement for the dryness of the green body, the smaller the preset moisture reference value is set. A method for setting the preset moisture reference value is provided. The preset moisture reference value is the maximum value of the moisture reference values ​​of all detection points of the green body that meet the actual situation requirements in the preparation history. A preset moisture reference value is provided. The value of the preset moisture reference value is 6%;

[0082] The drying time is increased and adjusted, and the moisture content of a special area of ​​the green body can be reduced by increasing the drying time. The drying time is the time for the vacuum drying oven to dry the green body; the drying temperature is increased and adjusted, and the overall moisture content of the green body can be reduced by increasing the drying temperature. The drying temperature is the temperature at which the vacuum drying oven dries the green body;

[0083] Among them, the position of each residual detection point is obtained, and the two residual detection points with the farthest distance are detected. If the distance corresponding to the pair of residual detection points is less than the preset distance, the detection point state is a dense state. If the distance corresponding to the pair of residual detection points is greater than or equal to the preset distance, the detection point state is a discrete state. The user can set the preset distance according to the actual scene and historical experience, and provide a value of the preset distance, which is 1 / 4 of the distance between the two farthest points on the same surface of the raw embryo.

[0084] Specifically, the grain type of the sintered product is determined according to the grain size range of the sintered product. The grain type of the sintered product includes a type of grains whose grain size of the sintered product is within a first preset grain size range, and a type of grains whose grain size of the sintered product is within a second preset grain size range.

[0085] The method for confirming the grain size of the sintered product is as follows: using Nano Measurer software to measure the size of each grain in the SEM photo;

[0086] The user can set the values ​​of the first preset grain size and the second preset grain size according to the actual application scenario. The higher the user's demand for accurate classification of grain types, the larger the value of the first preset grain size and the smaller the value of the second preset grain size. A first preset grain size and a second preset grain size are provided. The first preset grain size is the minimum value of all grain sizes of sintered finished products that meet the actual situation requirements in the preparation history, and the second preset grain size is the maximum value of all grain sizes of sintered finished products that meet the actual situation requirements in the preparation history; the first preset grain size range is smaller than the first preset grain size, and the second preset grain size range is larger than the second preset grain size.

[0087] Specifically, when the normal grain quantity reference value is less than the first preset quantity reference value, the adjustment method is determined according to the first type grain quantity reference value and the second type grain quantity reference value of the sintered finished product;

[0088] When the reference value of the number of one type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the first adjustment method of increasing the holding time of the second stage;

[0089] When the reference value of the number of the second type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the second adjustment method of reducing the sintering temperature in the second stage;

[0090] When the reference value of the number of the first type of grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of the second type of grains is greater than or equal to the third preset reference value, the adjustment mode is the third adjustment mode;

[0091] The increase in the holding time in the second stage is positively correlated with the grain size of the sintered product;

[0092] The decrease in the sintering temperature in the second stage is positively correlated with the grain size of the sintered product.

[0093] The second stage of holding time is increased and adjusted. By increasing the holding time of the second stage, the grains can grow, but the holding time should not be increased excessively. Too long a holding time may cause the grains to grow too large, resulting in uneven particles. The second stage of holding time is the period of time during which the temperature is kept constant after the sintering temperature is reached in the pressureless sintering furnace;

[0094] The sintering temperature of the second stage is adjusted to be reduced. Since too high a sintering temperature may cause the grains to grow too large, the grain size can be reduced by reducing the sintering temperature of the second stage. The sintering temperature of the second stage is the highest temperature of the pressureless sintering furnace during the sintering process.

[0095] Normal grain number reference value = the number of all grains whose grain size is greater than or equal to the first preset grain size and less than or equal to the second preset grain size that can be identified in five SEM photos / 5. The values ​​of the first preset number reference value, the second preset number reference value and the third preset number reference value can be set by the user according to the actual application scenario. The higher the user's demand for excellent performance of the ceramic, the larger the values ​​of the first preset number reference value and the second preset number reference value, and the smaller the value of the third preset number reference value. Provide a first preset number reference value, a second preset number reference value and a third preset number reference value. The first preset number reference value is 70% of the average value of the total number of grains, the second preset number reference value is 25% of the average value of the total number of grains, and the third preset number reference value is 5% of the average value of the total number of grains. The average value of the total number of grains = the number of all grains that can be identified in five SEM photos / 5.

[0096] Specifically, under the first preset condition, when the reference value of the number of the first type of grains in the sintered product is greater than the reference value of the number of the second type of grains, the third adjustment method is to reduce the heating rate of the first stage;

[0097] When the reference value of the number of the first type of grains in the sintered product is less than the reference value of the number of the second type of grains, the third adjustment method is to reduce the content of the sintering aid;

[0098] The decrease in the heating rate in the first stage is positively correlated with the uniformity of the grain size of the sintered product;

[0099] The reduction value of the sintering aid content is positively correlated with the uniformity of the grain size of the sintered product;

[0100] The first preset condition is when the reference value of the number of type one grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of type two grains is greater than or equal to the third preset reference value.

[0101] The heating rate in the first stage is reduced and adjusted. Too fast a heating rate will lead to uneven grain size. A small part of the grains may grow abnormally due to excessively high local temperature, while most of the grains maintain a small grain size. Reducing the heating rate in the first stage is conducive to uniform grain growth. The heating rate in the first stage refers to the rate at which the temperature rises over time from room temperature to the sintering temperature during the ceramic sintering process.

[0102] The sintering aid content is reduced and adjusted. When the sintering aid content is too high, it will lead to abnormal growth and uneven distribution of grains. By reducing the sintering aid content, the grain size can be made more uniform. The sintering aid content is the mass of the sintering aid added during the sintering of ceramics in a pressureless sintering furnace. The sintering aid used in the present invention is Ni;

[0103] Grain size uniformity = normal grain number reference value / average value of all grain numbers.

[0104] Specifically, the dense reference state of the sintered product is determined according to the porosity of the sintered product;

[0105] When the dense reference state is a first dense reference state in which the porosity of the sintered product is greater than a preset porosity, the heating rate of the first stage is adjusted to decrease, or the sintering temperature of the second stage is adjusted to increase;

[0106] When the dense reference state is a second dense reference state in which the porosity of the sintered product is less than or equal to the preset porosity, the sintered product is considered qualified and no adjustment is performed;

[0107] The decrease value of the heating rate in the first stage is positively correlated with the density reference value of the sintered product;

[0108] The increase in the sintering temperature in the second stage is positively correlated with the density reference value of the sintered product.

[0109] The calculation formula of porosity ε is: ε = m1ρwater / (m3-m1), ρwater is the medium density (deionized water is used, usually the density is 1.0g / cm 3 ); m1 is the mass of the dry sample in air, in g; m2 is the weight of the sample immersed in water after fully absorbing water, in g; m3 is the mass of the sample in air after fully absorbing water, in g. Boil the ceramic in deionized water for 2 hours, and measure its weight in water after cooling, m2; wipe the water on the surface of the sample with a wet paper towel, and measure its mass in air after fully absorbing water, m3; dry the sample, and measure its dry weight, m1.

[0110] The user can set the preset porosity value according to the actual application scenario. The higher the user's demand for excellent density of the ceramic, the smaller the preset porosity value. A preset porosity value is provided, and the preset porosity is the average value of all porosities of ceramics that meet the actual requirements in the preparation history.

[0111] When the porosity of the sintered product is less than or equal to the preset porosity, the heating rate of the first stage is first reduced. If the required porosity still cannot be obtained, the sintering temperature of the second stage is increased.

[0112] Since a heating rate that is too fast or a sintering temperature that is too low will increase the porosity of the ceramic and reduce the density, reducing the heating rate in the first stage or increasing the sintering temperature in the second stage can promote the densification of the ceramic.

[0113] Specifically, the product firing process includes three stages: the first stage is the heating process of the sintering device; the second stage is to maintain the sintering temperature for operation; and the third stage is the cooling process.

[0114] The sintering device adopted in the present invention is a pressureless sintering furnace.

[0115] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a bulletproof ceramic, It is characterized in that include: Determine the structural characteristic state of the green body according to the uniform thickness value and the curvature reference value, and determine the setting method of the humidity detection point according to the structural characteristic state of the green body; Determine the residual detection point according to the moisture reference value, and determine the detection point status according to the position of each residual detection point, and adjust the drying time or drying temperature under different detection point states; Determining the grain type of the sintered product according to the grain size range of the sintered product; When the normal grain quantity reference value is less than the first preset quantity reference value, the adjustment method is determined according to the first-class grain quantity reference value and the second-class grain quantity reference value of the sintered finished product as the first adjustment method for adjusting the holding time of the second stage, or the second adjustment method for adjusting the sintering temperature of the second stage, or the third adjustment method for adjusting the heating rate of the first stage or adjusting the content of the sintering aid; The density reference state of the sintered product is determined according to the porosity of the sintered product. Under the first density reference state, the heating rate of the first stage or the sintering temperature of the second stage is adjusted. When it reaches the second density reference state, the sintered product is considered qualified and no adjustment is performed.

2. A method for preparing a bulletproof ceramic according to claim 1, It is characterized in that The setting mode of the humidity detection points is determined according to the structural characteristic state of the green body, and the setting mode of the humidity detection points includes a conventional setting mode and a special setting mode.

3. A method for preparing a bulletproof ceramic according to claim 2, It is characterized in that The structural characteristic state of the green body is determined according to the uniform thickness value and the curvature reference value. The structural characteristic state of the green body includes a first structural characteristic state in which the uniform thickness value is less than or equal to a preset uniform thickness value and the curvature reference value is less than or equal to a preset curvature reference value, and a second structural characteristic state in which the uniform thickness value is greater than the preset uniform thickness value or the curvature reference value is greater than the preset curvature reference value.

4. A method for preparing a bulletproof ceramic according to claim 2, It is characterized in that The conventional arrangement is to divide the green body into a plurality of regions of equal area, and to set a humidity detection point at the center of each region; The special setting method is to divide the green body into several areas of equal area, set a humidity detection point at the center of each area, and increase the number of humidity detection points in areas with possibly higher humidity, such as depressions, protrusions, corners, etc.

5. A method for preparing a bulletproof ceramic according to claim 4, It is characterized in that Determine the state of the detection point according to the position of each residual detection point. If the detection point state is a dense state, increase the drying time. If the detection point state is a discrete state, increase the drying temperature. The increase in the drying time is negatively correlated with the maximum moisture reference value corresponding to the residual detection point; The increase value of the drying temperature is negatively correlated with the maximum moisture reference value corresponding to the residual detection point; The humidity detection point where the moisture reference value is greater than the preset moisture reference value is recorded as a residual detection point.

6. A method for preparing a bulletproof ceramic according to claim 5, It is characterized in that The grain type of the sintered product is determined according to the grain size range of the sintered product. The grain type of the sintered product includes a type of grain whose grain size of the sintered product is within a first preset grain size range, and a type of grain whose grain size of the sintered product is within a second preset grain size range.

7. A method for preparing a bulletproof ceramic according to claim 6, It is characterized in that When the normal grain quantity reference value is less than the first preset quantity reference value, determining the adjustment mode according to the first type grain quantity reference value and the second type grain quantity reference value of the sintered finished product; When the reference value of the number of one type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the first adjustment method of increasing the holding time of the second stage; When the reference value of the number of the second type of grains in the sintered product is greater than the second preset reference value, the adjustment method is the second adjustment method of reducing the sintering temperature in the second stage; When the reference value of the number of the first type of grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of the second type of grains is greater than or equal to the third preset reference value, the adjustment mode is the third adjustment mode; The increase in the holding time in the second stage is positively correlated with the grain size of the sintered product; The decrease in the sintering temperature in the second stage is positively correlated with the grain size of the sintered product.

8. A method for preparing a bulletproof ceramic according to claim 7, It is characterized in that Under the first preset condition, when the reference value of the number of the first type of grains in the sintered product is greater than the reference value of the number of the second type of grains, the third adjustment method is to reduce the heating rate of the first stage; When the reference value of the number of the first type of grains in the sintered product is less than the reference value of the number of the second type of grains, the third adjustment method is to reduce the content of the sintering aid; The decrease in the heating rate in the first stage is positively correlated with the uniformity of the grain size of the sintered product; The reduction value of the sintering aid content is positively correlated with the uniformity of the grain size of the sintered product; The first preset condition is when the reference value of the number of type one grains in the sintered product is greater than or equal to the third preset reference value and the reference value of the number of type two grains is greater than or equal to the third preset reference value.

9. The method for preparing a bulletproof ceramic according to claim 1, It is characterized in that Determine the dense reference state of the sintered product according to the porosity of the sintered product; When the dense reference state is a first dense reference state in which the porosity of the sintered product is greater than a preset porosity, the heating rate of the first stage is adjusted to decrease, or the sintering temperature of the second stage is adjusted to increase; When the dense reference state is a second dense reference state in which the porosity of the sintered product is less than or equal to the preset porosity, the sintered product is considered qualified and no adjustment is performed; The decrease value of the heating rate in the first stage is positively correlated with the density reference value of the sintered product; The increase in the sintering temperature in the second stage is positively correlated with the density reference value of the sintered product.

10. A method for preparing a bulletproof ceramic according to claim 9, It is characterized in that The product firing process includes three stages: the first stage is the heating process of the sintering device; The second stage is to maintain the sintering temperature for operation; The third stage is the cooling process.

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