Hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material as well as preparation method and application thereof

Abstract

The invention provides a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material as well as a preparation method and application thereof, and belongs to the technical field of ceramic materials. The preparation method comprises the following steps: firstly, respectively preparing soft-layer ceramic slurry and hard-layer ceramic slurry, then respectively carrying out tape casting to obtain hexagonal boron nitride green body laminates and ZrB2-SiC green body laminates, overlapping the two green body laminates, then carrying out degreasing and hot pressed sintering, and directionally arranging hexagonal boron nitride in the hexagonal boron nitride green body laminates to form a highly textured structure, by introducing the ZrB2-SiC green body layer sheets, the ceramic material has high strength and high toughness at the same time, and the ceramic material has excellent mechanical properties. The result of the embodiment shows that the bending strength of the prepared ceramic material is 97 MPa or above, and the fracture toughness is 4.10 MPa.m < 1 / 2 > or above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic materials, and particularly relates to a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of modern industry, the heat conduction performance of traditional ceramic materials is difficult to meet the needs of electronic basic materials in the microelectronic field, and high-thermal-conductivity materials with directional heat conduction performance are urgently needed. Hexagonal boron nitride (h-BN) has a theoretical thermal conductivity of 537 W / (m·K) in the direction perpendicular to the c-axis of the crystal grain and a theoretical thermal conductivity of only 4.1 W / (m·K) in the direction parallel to the c-axis, making it an ideal material for directional heat conduction. The thermal conductivity of h-BN ceramic is related to the organizational structure, and the higher the degree of texture and the larger the grain size, the closer the actual thermal conductivity is to the theoretical thermal conductivity. However, the increase in the grain size reduces the mechanical properties of h-BN ceramic, thereby reducing the reliability of h-BN ceramic in application.

[0003] Therefore, how to improve the mechanical properties of h-BN ceramic material has become a problem in the field. SUMMARY

[0004] The application aims to provide a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material and a preparation method and application thereof. The hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by the preparation method has high bending strength and fracture toughness.

[0005] In order to achieve the above application purposes, the application provides the following technical solutions: The application provides a preparation method of a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material, which comprises the following steps: (1) mixing hexagonal boron nitride, a first sintering aid, a first solvent, a first dispersant, a first binder and a first plasticizer to obtain a soft layer ceramic slurry; (2) mixing ZrB2, SiC, a second sintering aid, a second solvent, a second dispersant, a second binder and a second plasticizer to obtain a hard layer ceramic slurry; (3) respectively and sequentially defoaming and casting the soft layer ceramic slurry obtained in the step (1) and the hard layer ceramic slurry obtained in the step (2) to obtain a hexagonal boron nitride green layer sheet and a ZrB2-SiC green layer sheet; (4) sequentially pressing, degreasing and hot-pressing sintering the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet obtained in the step (3) after being overlapped to obtain a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; The steps (1) and (2) have no sequence.

[0006] Preferably, the average particle size of the hexagonal boron nitride in step (1) is 5-30 μm.

[0007] Preferably, the average particle size of the ZrB2 and SiC in step (2) is independently 0.5-1.5 μm.

[0008] Preferably, the defoaming time in step (3) is 45-60 min.

[0009] Preferably, the thickness of the hexagonal boron nitride green sheet in step (3) is 50-150 μm, and the thickness of the ZrB2-SiC green sheet is 50-130 μm.

[0010] Preferably, the pressure of the pressing in step (4) is 180-220 MPa, and the pressure holding time of the pressing is 20-40 min.

[0011] Preferably, the debinding in step (4) comprises first debinding, second debinding, third debinding, fourth debinding and fifth debinding in sequence; the temperature of the first debinding is 90-110 ℃, and the holding time of the first debinding is 30-60 min; the temperature of the second debinding is 190-210 ℃, and the holding time of the second debinding is 30-60 min; the temperature of the third debinding is 240-260 ℃, and the holding time of the third debinding is 30-60 min; the temperature of the fourth debinding is 290-310 ℃, and the holding time of the fourth debinding is 30-60 min; the temperature of the fifth debinding is 880-920 ℃, and the holding time of the fifth debinding is 200-300 min.

[0012] Preferably, the hot-pressing sintering in step (4) is: holding pressure at room temperature, 7-8 MPa for 2-4 min, then increasing temperature at a rate of ≤20 ℃, starting to increase pressure when the temperature increases to 1350-1450 ℃, increasing pressure to 28-32 MPa when the temperature increases to 1550-1650 ℃, and then holding pressure to continue increasing temperature to 1880-1920 ℃ for 50-65 min.

[0013] The application further provides a hexagonal boron nitride / ZrB2-SiC layered ceramic material prepared by the preparation method.

[0014] The application further provides an application of the hexagonal boron nitride / ZrB2-SiC layered ceramic material in the field of national defense science and technology and microelectronics.

[0015] The application provides a preparation method of a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material, which comprises the following steps: (1) mixing hexagonal boron nitride, a first sintering aid, a first solvent, a first dispersant, a first binder and a first plasticizer to obtain soft layer ceramic slurry; (2) mixing ZrB2, SiC, a second sintering aid, a second solvent, a second dispersant, a second binder and a second plasticizer to obtain hard layer ceramic slurry; (3) respectively and sequentially defoaming and casting the soft layer ceramic slurry obtained in the step (1) and the hard layer ceramic slurry obtained in the step (2) to obtain a hexagonal boron nitride green layer sheet and a ZrB2-SiC green layer sheet; and (4) sequentially pressing, debinding and hot-pressing sintering the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet obtained in the step (3) after being overlapped to obtain the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; and the steps (1) and (2) have no sequence. According to the application, the soft layer ceramic slurry and the hard layer ceramic slurry are prepared respectively, then the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet are obtained by casting respectively, the two green layer sheets are overlapped, and then debinding and hot-pressing sintering are performed, the hexagonal boron nitride in the hexagonal boron nitride green layer sheet is arranged in a high texture direction to make the ceramic material have high directional heat conduction performance, and the introduction of the ZrB2-SiC green layer sheet makes the ceramic material have high strength and high toughness, and has excellent mechanical properties. The results of the examples show that the bending strength of the ceramic material prepared by the application is above 97 MPa, the fracture toughness is above 4.10 MPa·m 1 / 2 above. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A macrograph of the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet prepared for Example 1; Figure 2 A schematic diagram of the loading direction for the bending strength and fracture toughness test of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; Figure 3 An SEM diagram of the fracture morphology of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared for Example 1; Figure 4 An SEM diagram of the fracture morphology of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared for Example 2; Figure 5 A temperature rise curve of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared for Example 1; Figure 6 A temperature rise curve of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared for Example 2; Figure 7 A schematic diagram of the test direction during the temperature rise curve test. DETAILED DESCRIPTION

[0017] The present application provides a preparation method of a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material, comprising the following steps: (1) mixing hexagonal boron nitride, a first sintering aid, a first solvent, a first dispersant, a first binder and a first plasticizer to obtain a soft layer ceramic slurry; (2) mixing ZrB2, SiC, a second sintering aid, a second solvent, a second dispersant, a second binder and a second plasticizer to obtain a hard layer ceramic slurry; (3) respectively and sequentially defoaming and casting the soft layer ceramic slurry obtained in the step (1) and the hard layer ceramic slurry obtained in the step (2) to obtain a hexagonal boron nitride green layer sheet and a ZrB2-SiC green layer sheet; (4) sequentially pressing, debinding and hot-pressing sintering the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet obtained in the step (3) after being overlapped to obtain a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; The steps (1) and (2) have no sequence.

[0018] Unless otherwise specified, the present application has no special limitation on the source of each raw material, and commercially available products known to those skilled in the art can be used.

[0019] In the present application, the first sintering aid is preferably α-Al2O3 and Y2O3.

[0020] In the present application, the average particle size of the hexagonal boron nitride is preferably 5-30 μm. As an embodiment, the average particle size of the hexagonal boron nitride can be specifically 5 μm, 10 μm, 20 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm. By controlling the average particle size of the hexagonal boron nitride within the above range, the present application can further improve the directional heat conduction performance of the ceramic material.

[0021] In the present application, the first sintering aid is preferably α-Al2O3 and Y2O3.

[0022] In the present application, the average particle size of the α-Al2O3 and Y2O3 is independently preferably 0.05-0.15 μm. As an embodiment, the average particle size of the α-Al2O3 and Y2O3 can be independently specifically 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm or 0.15 μm.

[0023] In the present application, the mass ratio of the α-Al2O3 and Y2O3 is preferably (4-6):3. As an embodiment, the mass ratio of the α-Al2O3 and Y2O3 can be specifically 4:3, 5:3 or 6:3.

[0024] In the present application, the mass ratio of the hexagonal boron nitride and the first sintering aid is preferably (6-8):3. As an embodiment, the mass ratio of the hexagonal boron nitride and the first sintering aid can be specifically 6:3, 7:3 or 8:3.

[0025] The present application controls the type and amount of the first sintering aid within the above range, and can reduce the sintering temperature.

[0026] In the present application, the first solvent is preferably toluene and isopropyl alcohol.

[0027] In the present application, the volume ratio of the toluene and isopropyl alcohol is preferably (0.5-1.5):1. As an embodiment, the volume ratio of the toluene and isopropyl alcohol can be specifically 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1 or 1.5:1.

[0028] The present application controls the type and ratio of the solvent within the above range, and can make the dissolution or dispersion of each component more sufficient.

[0029] In the present application, the first dispersant is preferably triethyl phosphate.

[0030] In the present application, the first binder is preferably polyvinyl butyral and glycerol.

[0031] As an embodiment, the grade of the polyvinyl alcohol can be specifically Butvar® B-98.

[0032] In the present application, the first plasticizer is preferably dibutyl phthalate.

[0033] In the present application, the volume ratio of the first plasticizer and glycerol in the first binder is preferably (0.5-1.5):1. As an embodiment, the volume ratio of the first plasticizer and glycerol in the first binder can be specifically 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1 or 1.5:1.

[0034] In the present application, the volume ratio of the total volume of the hexagonal boron nitride and the first sintering aid to the volume of the first solvent, the first dispersant, the first binder and the first plasticizer is preferably (9-11):(83-85):(1-3):(1-3):(1-3), and more preferably 10:84:2:2:2. Controlling the volume ratio of the components within the above range is more conducive to subsequent tape casting.

[0035] In the present application, the mixing of the hexagonal boron nitride, the first sintering aid, the first solvent, the first dispersant, the first binder and the first plasticizer is preferably as follows: the hexagonal boron nitride, the first sintering aid, the first solvent and the first dispersant are ball-mixed at a speed of 200-300 rpm for 20-30 h, and then the first binder and the first plasticizer are added in sequence and ball-mixed at a speed of 200-300 rpm for 20-30 h; and more preferably: the hexagonal boron nitride, the first sintering aid, the first solvent and the first dispersant are ball-mixed at a speed of 240 rpm for 24 h, and then the first binder and the first plasticizer are added in sequence and ball-mixed at a speed of 240 rpm for 24 h. Controlling the mixing method can make the components mix more uniformly.

[0036] In the present application, the ZrB2, SiC, second sintering aid, second solvent, second dispersant, second binder and second plasticizer are mixed to obtain a hard layer ceramic slurry.

[0037] In the present application, the average particle size of the ZrB2 and SiC is independently preferably 0.5-1.5 μm. As an embodiment, the average particle size of the ZrB2 and SiC can be specifically 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm or 1.5 μm. Controlling the average particle size of the ZrB2 and SiC within the above range can further improve the mechanical properties of the ceramic material.

[0038] In the present application, the second sintering aid, the second solvent, the second dispersant, the second binder and the second plasticizer are preferably the same as the first sintering aid, the first solvent, the first dispersant, the first binder and the first plasticizer, respectively, and will not be described here.

[0039] In the present application, the volume ratio of the ZrB2 to SiC is preferably 3-5:1. As an embodiment, the volume ratio of the ZrB2 to SiC can be specifically 3:1, 4:1 or 5:1.

[0040] In the present application, the mass ratio of the total mass of ZrB2 and SiC to the mass of the second sintering aid is preferably (6-8):3. As an embodiment, the mass ratio of the total mass of ZrB2 and SiC to the mass of the second sintering aid can be specifically 6:3, 7:3 or 8:3.

[0041] In the present application, the volume ratio of the total volume of ZrB2, SiC and the second sintering aid to the volume of the second solvent, the second dispersant, the second binder and the second plasticizer is preferably (18-22):(65-70):(3-5):(3-5):(3-5), more preferably 20:68:4:4:4. The present application controls the volume ratio of the components within the above range, which is more conducive to subsequent tape casting.

[0042] In the present application, the mixing of ZrB2, SiC, the second sintering aid, the second solvent and the second dispersant is preferably carried out by ball milling at a speed of 200-300 rpm for 20-30 h, and then the second binder and the second plasticizer are added in turn and ball-mixed at a speed of 200-300 rpm for 20-30 h; more preferably, ZrB2, SiC, the second sintering aid, the second solvent and the second dispersant are ball-mixed at a speed of 240 rpm for 24 h, and then the second binder and the second plasticizer are added in turn and ball-mixed at a speed of 240 rpm for 24 h. The present application controls the mixing method to make the mixing of the components more uniform.

[0043] After obtaining the soft layer ceramic slurry and the hard layer ceramic slurry, the present application carries out defoaming and tape casting on the soft layer ceramic slurry and the hard layer ceramic slurry respectively in turn to obtain hexagonal boron nitride green sheet and ZrB2-SiC green sheet.

[0044] In the present application, the defoaming time is preferably 45-60 min. As an embodiment, the defoaming time can be specifically 45 min, 50 min, 55 min or 60 min.

[0045] As an embodiment, the defoaming is carried out in a vacuum defoaming machine. The present application does not have special limitations on the model of the vacuum defoaming machine, and a conventional commercially available instrument can be used.

[0046] As an embodiment, the tape casting is carried out in a tape casting machine. The present application does not have special limitations on the model of the tape casting machine, and a conventional commercially available instrument can be used.

[0047] As an implementation form, the soft layer ceramic slurry and the hard layer ceramic slurry are poured into the trough of the casting machine respectively after defoaming, green tape is formed by the preset height of the casting doctor blade, and then drying is performed to obtain the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet.

[0048] In the present application, the preset height of the casting doctor blade of the soft layer ceramic slurry is preferably 450-900 μm.

[0049] In the present application, the preset height of the casting doctor blade of the hard layer ceramic slurry is preferably 200-600 μm.

[0050] In the present application, the temperature of the drying is preferably room temperature. The present application does not have special limitation on the time of the drying, which can be ensured to be complete.

[0051] As an implementation form, the shrinkage ratio of the hexagonal boron nitride green layer sheet before and after drying can be 7, 8 or 9; and the shrinkage ratio of the ZrB2-SiC green layer sheet before and after drying can be 4, 5 or 6.

[0052] In the present application, the thickness of the hexagonal boron nitride green layer sheet is preferably 50-150 μm. As an implementation form, the thickness of the hexagonal boron nitride green layer sheet can be specifically 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm.

[0053] In the present application, the thickness of the ZrB2-SiC green layer sheet is preferably 50-130 μm. As an implementation form, the thickness of the ZrB2-SiC green layer sheet can be specifically 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or 130 μm.

[0054] After the drying is completed, the present application preferably cuts the dried product to obtain the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet. The present application does not have special limitation on the operation of the cutting and the size of the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet, which can be cut into the required size by using the cutting technical solution well known by those skilled in the art.

[0055] After the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet are obtained, the present application overlaps the hexagonal boron nitride green layer sheet and the ZrB2-SiC green layer sheet, and then sequentially performs pressing, debinding and hot-pressing sintering to obtain the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material.

[0056] The present application does not have special limitation on the number of layers of the hexagonal boron nitride green sheet and the ZrB2-SiC green sheet, which can be selected according to actual needs.

[0057] The present application does not have special limitation on the overlapping order of the hexagonal boron nitride green sheet and the ZrB2-SiC green sheet, which can be selected according to actual needs.

[0058] As an embodiment, the hexagonal boron nitride green sheet and the ZrB2-SiC green sheet are overlapped in turn, i.e. one layer of hexagonal boron nitride green sheet, one layer of ZrB2-SiC green sheet, until the desired number of layers.

[0059] In the present application, the pressure of the pressing is preferably 180-220 MPa, and the holding time of the pressing is preferably 20-40 min. As an embodiment, the pressure of the pressing can be specifically 180 MPa, 190 MPa, 200 MPa, 210 MPa or 220 MPa, and the holding time of the pressing can be specifically 20 min, 25 min, 30 min, 35 min or 40 min.

[0060] In the present application, the debinding preferably comprises first debinding, second debinding, third debinding, fourth debinding and fifth debinding in turn. The temperature of the first debinding is preferably 90-110℃, and the holding time of the first debinding is preferably 30-60 min. The temperature of the second debinding is preferably 190-210℃, and the holding time of the second debinding is preferably 30-60 min. The temperature of the third debinding is preferably 240-260℃, and the holding time of the third debinding is preferably 30-60 min. The temperature of the fourth debinding is preferably 290-310℃, and the holding time of the fourth debinding is preferably 30-60 min. The temperature of the fifth debinding is preferably 880-920℃, and the holding time of the fifth debinding is preferably 200-300 min. In the present application, the heating rate during the debinding is preferably ≤2℃ / min, and the debinding is preferably carried out under nitrogen atmosphere.

[0061] As an implementation form, the temperature of the first debinding can be specifically 90℃, 95℃, 100℃, 105℃ or 110℃; the holding time of the first debinding can be specifically 30min, 40min, 50min or 60min; the temperature of the second debinding can be specifically 190℃, 195℃, 200℃, 205℃ or 210℃; the holding time of the second debinding can be specifically 30min, 40min, 50min or 60min; the temperature of the third debinding can be specifically 240℃, 245℃, 250℃, 255℃ or 260℃; the holding time of the third debinding can be specifically 30min, 40min, 50min or 60min; the temperature of the fourth debinding can be specifically 290℃, 295℃, 300℃, 305℃ or 310℃; the holding time of the fourth debinding can be specifically 30min, 40min, 50min or 60min; the temperature of the fifth debinding can be specifically 880℃, 885℃, 890℃, 895℃, 900℃, 905℃, 910℃, 915℃ or 920℃; and the holding time of the fifth debinding can be specifically 200min, 210min, 220min, 230min, 240min, 250min, 260min, 270min, 280min, 290min or 300min.

[0062] In the present application, the heating rate during the debinding process can be specifically 2℃ / min, 1.5℃ / min, 1℃ / min or 0.5℃ / min.

[0063] In the present application, the temperature and time of the debinding are controlled within the above range, so that the binder and the like can be removed sufficiently.

[0064] After the debinding is completed, the product of the debinding is preferably cooled, and then hot-pressed and sintered.

[0065] The operation of the cooling in the present application is not specially limited, and the product can be cooled to room temperature by using the cooling technical solution well known to those skilled in the art.

[0066] In the present application, the hot-pressing sintering is preferably: at room temperature, 7-8 MPa pressure maintaining for 2-4 min, then heating at a temperature increasing rate of ≤20℃, when the temperature rises to 1350-1450℃, start to pressurize, when the temperature rises to 1550-1650℃, the pressure reaches 28-32 MPa, then maintain the pressure and continue to heat to 1880-1920℃ for 50-65 min; more preferably: at room temperature, 7.5 MPa pressure maintaining for 3 min, then heating at a temperature increasing rate of ≤20℃, when the temperature rises to 1400℃, start to pressurize, when the temperature rises to 1600℃, the pressure reaches 30 MPa, then maintain the pressure and continue to heat to 1900℃ for 60 min. The present application controls the parameters of hot-pressing sintering in the above range, which can further improve the mechanical properties of the ceramic material.

[0067] In the present application, the hot-pressing sintering is preferably carried out under nitrogen atmosphere.

[0068] After the hot-pressing sintering is completed, the product of the hot-pressing sintering is preferably subjected to pressure releasing and temperature decreasing, when the temperature decreases to 1550-1650℃, the pressure decreases to 0 MPa, then cooled to room temperature, to obtain the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; more preferably, when the temperature decreases to 1600℃, the pressure decreases to 0 MPa, then cooled to room temperature, to obtain the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material.

[0069] The operation of the cooling is not specially limited in the present application, and the technical solution of cooling known to those skilled in the art can be adopted.

[0070] The present application first prepares the soft layer ceramic slurry and the hard layer ceramic slurry respectively, then respectively tapes the hexagonal boron nitride green sheet and the ZrB2-SiC green sheet, stacks the two green sheets, and then carries out pressing, degreasing and hot-pressing sintering, the hexagonal boron nitride in the hexagonal boron nitride green sheet is directionally arranged to form high texture, the ceramic material has high directional thermal conductivity, the introduction of the ZrB2-SiC green sheet makes the ceramic material have high strength and high toughness, and the process parameters are controlled to make the ceramic material have excellent mechanical properties.

[0071] The present application also provides the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by the preparation method.

[0072] The hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by the present application has high directional thermal conductivity and excellent bending strength and fracture toughness.

[0073] The present application also provides the application of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material in the field of national defense science and technology and microelectronics.

[0074] The application has no special limitation on the operation of the application, and the application of the technical solution known to those skilled in the art can be used.

[0075] The technical solutions in the application will be clearly and completely described below in combination with the embodiments in the application. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0076] The purity of toluene, isopropanol and triethyl phosphate in the embodiments is 99.7% (AR), and the purity of glycerol, Butvar B-98 polyvinyl butyral and dibutyl phthalate is 99.0% (AR).

[0077] Embodiment 1 A preparation method of a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material is as follows: (1) hexagonal boron nitride (average particle size is 20 μm), sintering aids (α-Al2O3 and Y2O3, the average particle size of α-Al2O3 and Y2O3 is 0.1 μm, the molar ratio of α-Al2O3 and Y2O3 is 5:3, and the mass ratio of hexagonal boron nitride and sintering aids is 7:3), solvents (toluene and isopropanol, the volume ratio of toluene and isopropanol is 1:1) and dispersants (triethyl phosphate) are ball-mixed at a rotation speed of 240 rpm for 24 h, and then binders (Butvar B-98 polyvinyl butyral and glycerol) and plasticizers (dibutyl phthalate, the volume ratio of dibutyl phthalate to glycerol in the binder is 1:1) are sequentially added and ball-mixed at a rotation speed of 240 rpm for 24 h to obtain a soft layered ceramic slurry, and the volume ratio of hexagonal boron nitride and sintering aids to solvents, dispersants, binders and plasticizers is 10:84:2:2:2; (2) ZrB2, SiC (average particle size of ZrB2, SiC is 1 μm), sintering aids (a-Al2O3 and Y2O3, average particle size of a-Al2O3 and Y2O3 is 0.1 μm, the molar ratio of a-Al2O3 and Y2O3 is 5:3, the mass ratio of the total mass of ZrB2 and SiC to the mass of sintering aids is 7:3), solvent (toluene and isopropyl alcohol, the volume ratio of toluene and isopropyl alcohol is 1:1) and dispersant (triethyl phosphate) are ball-mixed at a speed of 240 rpm for 24 h, then the binder (Butvar® B-98 polyvinyl butyral and glycerol) and plasticizer (dibutyl phthalate, the volume ratio of dibutyl phthalate to glycerol in the binder is 1:1) are added in turn and ball-mixed at a speed of 240 rpm for 24 h to obtain a hard layer ceramic slurry, the volume ratio of ZrB2, SiC and sintering aids to solvent, dispersant, binder and plasticizer is 20:68:4:4:4; (3) The soft layer ceramic slurry obtained in step (1) is degassed in a vacuum degassing machine for 45 min, then poured into a casting machine tank, and a green tape is formed by a casting doctor blade with a preset height (the preset height is 900 μm), and after drying at room temperature, a hexagonal boron nitride green layer sheet with a diameter of Φ50 mm is cut, and the thickness of the hexagonal boron nitride green layer sheet is 100 μm; (4) The hard layer ceramic slurry obtained in step (2) is degassed in a vacuum degassing machine for 45 min, then poured into a casting machine tank, and a green tape is formed by a casting doctor blade with a preset height (the preset height is 550 μm), and after drying at room temperature, a ZrB2-SiC green layer sheet with a diameter of Φ50 mm is cut, and the thickness of the ZrB2-SiC green layer sheet is 100 μm; (5) 30 pieces of the hexagonal boron nitride green layer sheet obtained in step (3) and 30 pieces of the ZrB2-SiC green layer sheet obtained in step (4) are overlapped in turn (the lowest layer is hexagonal boron nitride), and then pressure is maintained at 200 MPa for 30 min, and then the temperature is raised to 100℃ at a rate of 2℃ / min, and the temperature is maintained for 60 min, and then the temperature is continuously raised to 200℃, and the temperature is maintained for 60 min, and then the temperature is further raised to 250℃, and the temperature is maintained for 60 min, and then the temperature is continuously raised to 300℃, and the temperature is maintained for 60 min, and finally the temperature is raised to 900℃, and the temperature is maintained for 300 min, and then the temperature is cooled to room temperature, and then the temperature is raised at a rate of 20℃ / min under a nitrogen atmosphere at a pressure of 0.98 MPa, and the temperature is raised to 1400℃, and then the pressure is raised when the temperature is raised to 1600℃, and the pressure is maintained when the temperature is continuously raised to 1900℃, and the temperature is maintained for 60 min, and then the pressure is released when the temperature is reduced to 1600℃, and then the temperature is cooled to room temperature to obtain a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material.

[0078] Macroscopic images of the hexagonal boron nitride green sheets and ZrB2-SiC green sheets prepared in Example 1 are shown below. Figure 1 As shown, (a) is a hexagonal boron nitride green sheet, and (b) is a ZrB2-SiC green sheet.

[0079] Example 2 The difference between Example 2 and Example 1 is that: in step (3), the preset height of the casting blade is 450 μm, and the thickness of the resulting hexagonal boron nitride green sheet is 50 μm; in step (4), the preset height of the casting blade is 275 μm, and the thickness of the resulting ZrB2-SiC green sheet is 50 μm; other parameters are the same as in Example 1.

[0080] The flexural strength and fracture toughness of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic materials prepared in Examples 1 and 2 were tested (the test standards were the three-point bending method and the single-sided notched beam method), and the results are shown in Table 1.

[0081] A schematic diagram of the loading direction for testing the flexural strength and fracture toughness of hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic materials is shown below. Figure 2 As shown, P is the load direction.

[0082] Table 1. Flexural strength and fracture toughness of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic materials prepared in Examples 1 and 2

[0083] As can be seen from Table 1, the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by this invention has excellent flexural strength and fracture toughness.

[0084] SEM images of the fracture morphology of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared in Example 1 are shown below. Figure 3 As shown, the SEM image of the fracture morphology of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared in Example 2 is shown below. Figure 4 As shown. From Figure 3 and Figure 4 It can be seen that the fracture modes of the soft layer and the hard layer of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material are different during fracture. In the soft layer, the hexagonal boron nitride layers are pulled out and bent, absorbing fracture energy and improving fracture toughness; while the fracture that occurs in the zirconium diboride-silicon carbide layer is transgranular fracture and intergranular fracture. The presence of the zirconium diboride-silicon carbide layer improves the mechanical properties.

[0085] The temperature rise curves of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic materials prepared in Examples 1 and 2 were tested, and the results are as follows: Figure 5 andFigure 6 As shown in the figure, the test direction schematic diagram during the temperature rise curve test is as shown in the figure Figure 7 The test method of the temperature rise curve is: an infrared thermal imaging camera (Vario CAM hr head 680) is used to record the temperature rise of the ceramic material on a preset 100 DEG C heating table with a frame frequency of 50Hz, so as to characterize the directional heat conduction performance of the sample when the heat source is in surface contact with the sample, the sample size is 5mm 5mm 5mm, and the IRBIS3 software is used for data processing.

[0086] From Figure 5 and Figure 6 It can be seen that the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material has different heat conduction capacities in different directions, and the heat conduction capacity has anisotropy. When the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material is in contact with the heat source in the direction shown in a of Figure 7 the heat conduction capacity is obviously better.

[0087] In summary, the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by the application has excellent heat conduction performance, and also has excellent mechanical properties.

[0088] The above only describes the preferred embodiments of the application, and it should be pointed out that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the application, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1.A method for preparing a hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material, comprising the following steps: (1) mixing hexagonal boron nitride, a first sintering aid, a first solvent, a first dispersant, a first binder and a first plasticizer to obtain a soft layer ceramic slurry; (2) mixing ZrB 2, SiC, a second sintering aid, a second solvent, a second dispersant, a second binder and a second plasticizer to obtain a hard layer ceramic slurry; (3) respectively and sequentially defoaming and casting the soft layer ceramic slurry obtained in step (1) and the hard layer ceramic slurry obtained in step (2) to obtain a hexagonal boron nitride green layer sheet and a ZrB 2-SiC green layer sheet; (4) sequentially pressing, debinding and hot-pressing sintering the hexagonal boron nitride green layer sheet and the ZrB 2-SiC green layer sheet obtained in step (3) after being overlapped to obtain the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material; the steps (1) and (2) have no sequence; the average particle size of the hexagonal boron nitride in step (1) is 5-30 μm; the average particle size of ZrB 2 and SiC in step (2) is independently 0.5-1.5 μm; the defoaming time in step (3) is 45-60 min; the thickness of the hexagonal boron nitride green layer sheet in step (3) is 50-150 μm, and the thickness of the ZrB 2-SiC green layer sheet is 50-130 μm; the pressure of the pressing in step (4) is 180-220 MPa, and the pressure holding time of the pressing is 20-40 min; the debinding in step (4) comprises sequentially a first debinding, a second debinding, a third debinding, a fourth debinding and a fifth debinding; the temperature of the first debinding is 90-110 ℃, and the holding time of the first debinding is 30-60 min; the temperature of the second debinding is 190-210 ℃, and the holding time of the second debinding is 30-60 min; the temperature of the third debinding is 240-260 ℃, and the holding time of the third debinding is 30-60 min; the temperature of the fourth debinding is 290-310 ℃, and the holding time of the fourth debinding is 30-60 min; the temperature of the fifth debinding is 880-920 ℃, and the holding time of the fifth debinding is 200-300 min; the hot-pressing sintering in step (4) is: holding pressure at room temperature, 7-8 MPa for 2-4 min, then increasing temperature at a rate of ≤20 ℃, starting to increase pressure when the temperature increases to 1350-1450 ℃, increasing pressure to 28-32 MPa when the temperature increases to 1550-1650 ℃, and then holding pressure to continue increasing temperature to 1880-192 ℃ for 50-65 min. 9.The hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material prepared by the method of any one of claims 1-8. 10.The use of the hexagonal boron nitride / zirconium diboride-silicon carbide layered ceramic material of claim 9 in the field of national defense technology and microelectronics. ​ ​ ​ 2. The production method according to claim 1, characterized by, ​ 3. The preparation method according to claim 1, characterized in that, ​ 4. The method of claim 1, wherein, ​ 5. The preparation method according to claim 1, characterized in that, ​ 6. The method of claim 1, wherein, ​ 7. The preparation method according to claim 1, characterized in that, ​ 8. The method of claim 1, wherein, ​ ​ ​

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