CN115180957B - Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance - Google Patents

Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance Download PDF

Info

Publication number
CN115180957B
CN115180957B CN202210812537.2A CN202210812537A CN115180957B CN 115180957 B CN115180957 B CN 115180957B CN 202210812537 A CN202210812537 A CN 202210812537A CN 115180957 B CN115180957 B CN 115180957B
Authority
CN
China
Prior art keywords
boron nitride
hexagonal boron
ceramic
nitride ceramic
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210812537.2A
Other languages
Chinese (zh)
Other versions
CN115180957A (en
Inventor
贾德昌
牛波
杨治华
蔡德龙
段文九
段小明
周玉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harbin Institute of Technology
Original Assignee
Harbin Institute of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Harbin Institute of Technology filed Critical Harbin Institute of Technology
Priority to CN202210812537.2A priority Critical patent/CN115180957B/en
Publication of CN115180957A publication Critical patent/CN115180957A/en
Application granted granted Critical
Publication of CN115180957B publication Critical patent/CN115180957B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/583—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on boron nitride
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/64—Burning or sintering processes
    • C04B35/645—Pressure sintering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/602—Making the green bodies or pre-forms by moulding
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/606—Drying
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • C04B2235/6567—Treatment time
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/658—Atmosphere during thermal treatment
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Abstract

A preparation method of hexagonal boron nitride ceramics with excellent heat wave transmission performance relates to a preparation method of hexagonal boron nitride ceramics. The method aims to solve the problem that the dielectric loss of the hexagonal boron nitride ceramic is abnormally increased along with the temperature increase at high temperature. The preparation method comprises the following steps: weighing h-BN powder and silica sol solution, uniformly mixing, then loading into a steel mould, carrying out oscillation prepressing treatment, carrying out drying treatment, and placing a ceramic dry blank into a graphite crucible for air pressure sintering to obtain hexagonal boron nitride ceramic with a texture index of 2000-8000, wherein the hexagonal boron nitride ceramic is used as a thermal wave-transparent material. The hexagonal boron nitride ceramic has a texture index of 2000-8000, low defect concentration, excellent heat wave transmission performance, and capability of preventing abnormal attenuation of the wave transmission performance of the hexagonal boron nitride ceramic at high temperature.

Description

Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance
Technical Field
The invention relates to a preparation method of hexagonal boron nitride ceramic with excellent heat wave transmission performance.
Background
The aircraft antenna housing is positioned at the head of an aircraft and is an important device for protecting the normal operation of an aircraft guidance system in an extreme high-temperature environment. The radome material needs to have excellent dielectric loss with less change with temperature rise so as to ensure the thermal wave-transparent performance of the radome and the accurate guidance of the aircraft. The hexagonal boron nitride (h-BN) ceramic has the advantages of low normal-temperature dielectric constant and dielectric loss, excellent thermal shock resistance, good chemical stability, high thermal stability, excellent processability and the like, and is a main candidate material of a new-generation aircraft radome. However, the dielectric loss of the hexagonal boron nitride ceramic at high temperature can be sharply increased along with the temperature rise, so that the thermal wave transmission performance of the hexagonal boron nitride ceramic is seriously influenced, and the practical application requirement of the antenna housing of the aircraft is difficult to meet.
Disclosure of Invention
The invention provides a preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance, aiming at solving the problem that dielectric loss of the hexagonal boron nitride ceramic is abnormally increased along with temperature increase at high temperature.
The preparation method of the hexagonal boron nitride ceramic with excellent thermal wave transmission performance comprises the following steps:
selecting h-BN powder with graphitization index of 1.6-2.5, purity of 99.0-99.999%, grain size of 10-50 mu m, high crystallinity, high purity and high sheet layer as raw material; the h-BN powder with the low graphitization index has high crystallinity, contains fewer intrinsic defect ions, has low conductivity of the intrinsic defect ions excited at high temperature, and can generate low dielectric loss, so that the heat transmission performance of the hexagonal boron nitride ceramic is improved; the h-BN powder with higher purity contains fewer impurity defect ions, and can generate lower dielectric loss; the h-BN powder with larger grain size has a typical lamellar structure, the directional arrangement of crystal grains is easier to occur under the action of oscillation prepressing treatment, and the electrical conductivity of the h-BN crystal in the direction vertical to the lamellar direction is obviously lower than that in the direction parallel to the lamellar direction, so that the electrical conductivity of the hexagonal boron nitride ceramic is favorably reduced after the directional arrangement, the dielectric loss of the hexagonal boron nitride ceramic is reduced, and the heat wave-transmitting performance of the hexagonal boron nitride ceramic is improved.
Weighing 10-50% of h-BN powder and the balance of silica sol solution according to mass fraction;
step three, uniformly mixing the raw materials by a vacuum stirrer to obtain ceramic material viscous slurry;
step four, the ceramic material viscous slurry is loaded into a steel mould and placed on a press to be subjected to oscillation prepressing treatment, so that a ceramic blank body is obtained; the oscillation prepressing treatment is carried out on the basis of a preset pressure value, the pressure value is changed up and down under the action of certain amplitude and frequency, the h-BN powder can be more easily subjected to the phenomenon of directional arrangement, and the hexagonal boron nitride ceramic with high texture index is prepared, so that the dielectric loss is reduced, and the heat wave transmission performance is improved.
Putting the ceramic blank into an oven for drying treatment to obtain a ceramic dried blank;
and sixthly, placing the ceramic dry blank into a graphite crucible, covering h-BN powder on the periphery of the graphite crucible, and placing the graphite crucible into an atmosphere sintering furnace for air pressure sintering to obtain the hexagonal boron nitride ceramic with the texture index of 2000-8000, wherein the hexagonal boron nitride ceramic is used as a heat wave transmission material.
The principle and the beneficial effects of the invention are as follows:
in order to solve the problem of abnormal increase of dielectric loss of the hexagonal boron nitride ceramic at high temperature, the invention adopts h-BN powder with low graphitization index (high crystallinity), high purity and large particle size as a raw material and adopts silica sol solution as a sintering aid, and the hexagonal boron nitride ceramic with the texture index of 2000-8000 and low defect concentration is obtained through raw material slurry preparation, oscillation prepressing treatment, drying treatment and air pressure sintering, so that abnormal attenuation of the wave permeability of the hexagonal boron nitride ceramic at high temperature is prevented. The method comprises the following specific steps:
1. the method adopts the h-BN powder with low graphitization index, high purity and large particle size as the raw material, so that h-BN crystal grains can be more easily textured in the prepressing process, and the dielectric loss of the h-BN crystal grains is reduced by reducing the conductivity in the direction vertical to the lamella. Meanwhile, the h-BN powder with low graphitization index and high purity contains less defects and impurity ions, and can reduce the dielectric loss of the hexagonal boron nitride ceramic caused by defect conductance to a certain extent, so that the heat wave-transmitting performance of the hexagonal boron nitride ceramic is improved.
2. According to the invention, h-BN grains can be highly directionally arranged through vacuum stirring mixing and oscillation pre-pressing treatment of h-BN powder and a silica sol solution, and fused quartz ceramics with low melting point and excellent wave-transmitting performance can be generated in situ through subsequent drying treatment and air pressure sintering, so that the densification process of hexagonal boron nitride ceramics is promoted, and then the hexagonal boron nitride ceramics with high densification degree and high texturing degree are obtained, thereby improving the heat wave-transmitting performance of the hexagonal boron nitride ceramics.
Drawings
FIG. 1 is a scanning electron micrograph of hexagonal boron nitride ceramic prepared in example 1;
FIG. 2 is a scanning electron micrograph of hexagonal boron nitride ceramic prepared in example 2;
FIG. 3 is a graph of dielectric loss tangent versus temperature for hexagonal boron nitride ceramics.
Detailed Description
The technical scheme of the invention is not limited to the specific embodiments listed below, and any reasonable combination of the specific embodiments is included.
The first embodiment is as follows: the preparation method of the hexagonal boron nitride ceramic with excellent heat wave transmission performance comprises the following steps:
selecting h-BN powder with the graphitization index of 1.6-2.5, the purity of 99.0-99.999 percent, the grain size of 10-50 mu m, high crystallinity, high purity and high lamellar shape as a raw material; the h-BN powder with the low graphitization index has high crystallinity, contains fewer intrinsic defect ions, has low conductivity of the intrinsic defect ions excited at high temperature, and can generate low dielectric loss, so that the heat transmission performance of the hexagonal boron nitride ceramic is improved; the h-BN powder with higher purity contains fewer impurity defect ions, and can also generate lower dielectric loss; the h-BN powder with larger grain size has a typical lamellar structure, the directional arrangement of crystal grains is easier to occur under the action of oscillation prepressing treatment, and the electrical conductivity of the h-BN crystal in the direction vertical to the lamellar direction is obviously lower than that in the direction parallel to the lamellar direction, so that the electrical conductivity of the hexagonal boron nitride ceramic is favorably reduced after the directional arrangement, the dielectric loss of the hexagonal boron nitride ceramic is reduced, and the heat wave-transmitting performance of the hexagonal boron nitride ceramic is improved.
Weighing 10-50% of h-BN powder and the balance of silica sol solution according to mass fraction;
step three, uniformly mixing the raw materials by a vacuum stirrer to obtain ceramic material viscous slurry;
step four, the ceramic material viscous slurry is loaded into a steel mould and placed on a press to be subjected to oscillation prepressing treatment, so that a ceramic blank body is obtained; the oscillation prepressing treatment is carried out on the basis of a preset pressure value, the pressure value is changed up and down under the action of certain amplitude and frequency, the phenomenon of directional arrangement of h-BN powder can be more easily caused, and the hexagonal boron nitride ceramic with high texture index is prepared, so that the dielectric loss is reduced, and the heat wave transmission performance is improved.
Putting the ceramic blank body into an oven for drying treatment to obtain a ceramic dried blank body;
and sixthly, placing the ceramic dry blank into a graphite crucible, covering h-BN powder on the periphery of the graphite crucible, and placing the graphite crucible into an atmosphere sintering furnace for air pressure sintering to obtain the hexagonal boron nitride ceramic with the texture index of 2000-8000, wherein the hexagonal boron nitride ceramic is used as a heat wave transmission material.
In order to solve the problem of abnormal increase of dielectric loss of the hexagonal boron nitride ceramic at a high temperature, the embodiment adopts h-BN powder with low graphitization index (high crystallinity), high purity and large particle size as a raw material, adopts a silica sol solution as a sintering aid, and obtains the hexagonal boron nitride ceramic with a texture index of 2000-8000 and low defect concentration through raw material slurry preparation, oscillation prepressing treatment, drying treatment and air pressure sintering, thereby preventing abnormal attenuation of the wave permeability of the hexagonal boron nitride ceramic at the high temperature. The method comprises the following specific steps:
1. the embodiment adopts the h-BN powder with low graphitization index, high purity and large particle size as the raw material, so that h-BN crystal grains can be more easily textured in the prepressing process, and the dielectric loss of the h-BN crystal grains is reduced by reducing the conductivity in the direction vertical to the lamella. Meanwhile, the h-BN powder with low graphitization index and high purity contains less defects and impurity ions, and can reduce the dielectric loss of the hexagonal boron nitride ceramic caused by defect conductance to a certain extent, so that the heat wave-transmitting performance of the hexagonal boron nitride ceramic is improved.
2. According to the embodiment, h-BN grains can be highly directionally arranged through vacuum stirring mixing and oscillation pre-pressing treatment of h-BN powder and a silica sol solution, and fused quartz ceramics with low melting point and excellent wave-transmitting performance can be generated in situ through subsequent drying treatment and air pressure sintering, so that the densification process of hexagonal boron nitride ceramics is promoted, the hexagonal boron nitride ceramics with high densification degree and high texturing degree are further obtained, and the heat wave-transmitting performance of the hexagonal boron nitride ceramics is improved.
The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: step two, nano SiO in the silica sol solution 2 The content of the particles is 20-60 wt.%.
The third concrete implementation mode: the first or second difference between the present embodiment and the specific embodiment is: and step three, mixing the materials by using the vacuum mixer for 12 to 36 hours.
The fourth concrete implementation mode: the difference between this embodiment and one of the first to third embodiments is: and step three, the vacuum degree of the vacuum stirrer is 0.09-0.1 MPa when the vacuum stirrer is used for mixing.
The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: the oscillation prepressing treatment process comprises the following steps: the prepressing pressure is 5-50 MPa, the pressure oscillation amplitude is 5-15% of the set pressure value, the oscillation frequency is 0.5-2.5 Hz, and the pressure maintaining time is 1-10 min.
The sixth specific implementation mode: the fifth embodiment is different from the fifth embodiment in that: the oscillation prepressing treatment process comprises the following steps: the prepressing pressure is 20MPa, the pressure oscillation amplitude is 10% of a set pressure value, the oscillation frequency is 1.5Hz, and the pressure maintaining time is 5min.
The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: the drying process comprises the following steps: the drying temperature is 50-75 ℃ and the drying time is 3-10 hours.
The specific implementation mode eight: the seventh embodiment is different from the seventh embodiment in that: the drying process comprises the following steps: the drying temperature was 60 ℃ and the time was 6 hours.
The specific implementation method nine: the difference between this embodiment and the first to eighth embodiments is: the process of the air pressure sintering comprises the following steps: the sintering temperature is 1650-2200 ℃, the pressure is 5-50 MPa, the sintering atmosphere is nitrogen, and the sintering time is 60-120 minutes.
The specific implementation mode is ten: the present embodiment differs from the ninth embodiment in that: the process of the air pressure sintering comprises the following steps: the sintering temperature is 1900 ℃, the pressure is 15MPa, the sintering atmosphere is nitrogen, and the sintering time is 90 minutes.
Example 1
The preparation method of the hexagonal boron nitride ceramic with excellent thermal wave-transparent performance of the embodiment is carried out according to the following steps:
step 1, selecting h-BN powder with graphitization index of 2.1, purity of 99.5% and particle size of 15 mu m as raw material;
step 2, weighing 50% of h-BN powder according to mass fraction, and then weighing the rest of silica sol solution; nano SiO in silica sol solution 2 The content of the particles was 40wt.%;
step 3, fully and uniformly mixing the raw materials by a vacuum mixer for 24 hours under the vacuum degree of 0.09MPa to obtain ceramic material viscous slurry;
step 4, the mixed viscous slurry is loaded into a steel mould and placed on a press for oscillation prepressing treatment, the prepressing pressure is set to be 10MPa, the pressure oscillation amplitude is 5 percent of the set pressure value, the oscillation frequency is 1Hz, and the pressure maintaining time is 3min, so that a ceramic forming blank body is obtained;
and 5, putting the ceramic blank into an oven for drying treatment at the temperature of 50 ℃ for 3 hours to obtain a ceramic dried blank.
Step 6, carrying out powder embedding treatment on the ceramic dry blank, wherein the embedded powder is h-BN powder, putting the h-BN powder into an atmosphere sintering furnace for carrying out air pressure sintering, the sintering temperature is 2000 ℃, the pressure is 20MPa, the sintering atmosphere is nitrogen, the time is 60 minutes, and after cooling along with the furnace, the ceramic dry blank can obtain the ceramic with the texture index of 2300 and the dielectric loss of 8 multiplied by 10 at the temperature of 1000 DEG C -3 The hexagonal boron nitride ceramic of (2) is used as a thermal wave-transmitting material. FIG. 1 is a scanning electron micrograph of hexagonal boron nitride ceramic prepared according to example 1; the h-BN crystal grains of the hexagonal boron nitride ceramic have certain directional arrangement characteristics, and the texture index is 2300.
Wherein, the calculation process of the texture Index (IOP) is as follows:
Figure BDA0003739793520000051
I 100 and I 002 Respectively represent diffraction intensities, I 'of corresponding crystal planes on the surface of the hexagonal boron nitride ceramic' 100 And l' 002 Respectively represent the diffraction intensity of corresponding crystal faces on the side surface of the hexagonal boron nitride ceramics, and the larger the texture index is, the more obvious the directional arrangement phenomenon of the hexagonal boron nitride ceramics is.
Example 2
The preparation method of the hexagonal boron nitride ceramic with excellent thermal wave-transparent performance of the embodiment is carried out according to the following steps:
step 1, selecting h-BN powder with graphitization index of 1.8, purity of 99.9% and particle size of 20 mu m as raw material;
step 2, weighing 45% of h-BN powder according to mass fraction, and then weighing the rest of silica sol solution; nano SiO in silica sol solution 2 Content of particles was 50wt.%;
step 3, fully and uniformly mixing the raw materials by a vacuum mixer for 36 hours under the vacuum degree of 0.1MPa to obtain ceramic material viscous slurry;
step 4, the mixed viscous slurry is loaded into a steel die and placed on a press for oscillation prepressing treatment, the prepressing pressure is set to be 20MPa, the pressure oscillation amplitude is 10 percent, the oscillation frequency is 1.5Hz, and the pressure maintaining time is 5min, so that a ceramic forming blank body is obtained;
and 5, putting the ceramic blank into an oven for drying treatment at the temperature of 70 ℃ for 5 hours to obtain a ceramic dried blank.
Step 6, carrying out powder embedding treatment on the ceramic dry blank, wherein the embedded powder is h-BN powder, putting the h-BN powder into an atmosphere sintering furnace for carrying out air pressure sintering, the sintering temperature is 1900 ℃, the pressure is 15MPa, the sintering atmosphere is nitrogen, the time is 90 minutes, and after cooling along with the furnace, the ceramic dry blank can obtain a texture index of 6500 and dielectric loss of 5.6 multiplied by 10 at 1000 DEG C -3 The hexagonal boron nitride ceramic of (2) is used as a thermal wave-transmitting material. FIG. 2 is a scanning electron micrograph of hexagonal boron nitride ceramic prepared according to example 2; h-BN crystal grains of the hexagonal boron nitride ceramicHas stronger directional arrangement characteristic and the texture index of 6500.
Comparative example 1:
the preparation method of the hexagonal boron nitride ceramic of the embodiment is carried out according to the following steps:
step 1, selecting h-BN powder with the graphitization index of 3, the purity of 95.5 percent and the particle size of 5 mu m as a raw material;
step 2, weighing 45% of h-BN powder according to mass fraction, and then weighing the rest of silica sol solution; nano SiO in silica sol solution 2 Content of particles was 50wt.%;
step 3, fully and uniformly mixing the raw materials by a vacuum mixer for 30 hours under the vacuum degree of 0.1MPa to obtain ceramic material viscous slurry;
step 4, the mixed viscous slurry is loaded into a steel die and placed on a press for prepressing treatment, the constant prepressing pressure is set to be 20MPa, and the pressure maintaining time is set to be 10min, so that a ceramic forming blank body is obtained;
and 5, putting the ceramic blank into an oven for drying treatment at the temperature of 70 ℃ for 5 hours to obtain a ceramic dried blank.
Step 6, carrying out powder embedding treatment on the ceramic dry blank, wherein the embedded powder is h-BN powder, putting the h-BN powder into an atmosphere sintering furnace for carrying out air pressure sintering, the sintering temperature is 2000 ℃, the pressure is 15MPa, the sintering atmosphere is nitrogen, the time is 90 minutes, and after cooling along with the furnace, the ceramic dry blank with the texture index of 120 and the dielectric loss of 1.4 multiplied by 10 at the temperature of 1000 ℃ can be obtained -2 Hexagonal boron nitride ceramics.
FIG. 3 is a graph of dielectric loss tangent versus temperature for hexagonal boron nitride ceramics; in the figure, 1 is a conventional hexagonal boron nitride ceramic prepared by a comparative example, 2 is a hexagonal boron nitride ceramic prepared by example 1, and 3 is a hexagonal boron nitride ceramic prepared by example 5. The hexagonal boron nitride ceramics prepared in examples 1 and 2 have low dielectric loss tangent values at high temperatures and show excellent heat wave-transmitting properties.

Claims (9)

1. A preparation method of hexagonal boron nitride ceramics with excellent heat wave transmission performance is characterized by comprising the following steps: the preparation method of the hexagonal boron nitride ceramic with excellent thermal wave transmission performance comprises the following steps:
selecting the material with the graphitization index of 1.6-2.5, the purity of 99.0-99.999% and the particle size of 10-50 mu mh-a BN powder;
weighing 10-50% of the mixture according to mass fractionhBN powder and the balance of silica sol solution are used as raw materials;
step three, uniformly mixing the raw materials by a vacuum stirrer to obtain ceramic material viscous slurry;
step four, the ceramic material viscous slurry is loaded into a steel mould and placed on a press to be subjected to oscillation prepressing treatment, and a ceramic blank body is obtained; step four, the oscillation prepressing treatment process comprises the following steps: the prepressing pressure is 5 to 50MPa, the pressure oscillation amplitude is 5 to 15 percent of the set pressure value, the oscillation frequency is 0.5 to 2.5Hz, and the pressure maintaining time is 1 to 10min;
putting the ceramic blank into an oven for drying treatment to obtain a ceramic dried blank;
putting the ceramic dry blank into a graphite crucible, and covering the periphery of the ceramic dry blankhAnd (4) putting BN powder into an atmosphere sintering furnace for atmospheric pressure sintering to obtain the hexagonal boron nitride ceramic with the texture index of 2000-8000, and using the hexagonal boron nitride ceramic as a heat wave transmission material.
2. The method for producing a hexagonal boron nitride ceramic having excellent heat wave-transmitting properties according to claim 1, characterized in that: step two, nano SiO in the silica sol solution 2 The content of the granules is 20 to 60wt.%.
3. The method for producing a hexagonal boron nitride ceramic having excellent heat wave-transmitting properties according to claim 1, characterized in that: and step three, mixing the materials by using the vacuum stirrer for 12 to 36 hours.
4. The method for producing a hexagonal boron nitride ceramic having excellent thermal wave-transmitting properties according to claim 1, characterized in that: and step three, when the vacuum stirrer is used for mixing, the vacuum degree of the vacuum stirrer is 0.09 to 0.1MPa.
5. The method for producing a hexagonal boron nitride ceramic having excellent heat wave-transmitting properties according to claim 1, characterized in that: step four, the oscillation prepressing treatment process comprises the following steps: the prepressing pressure is 20MPa, the pressure oscillation amplitude is 10% of a set pressure value, the oscillation frequency is 1.5Hz, and the pressure maintaining time is 5min.
6. The method for producing a hexagonal boron nitride ceramic having excellent thermal wave-transmitting properties according to claim 1, characterized in that: the drying process comprises the following steps: the drying temperature is 50 to 75 ℃, and the drying time is 3 to 10 hours.
7. The method for producing a hexagonal boron nitride ceramic having excellent thermal wave-transmitting properties according to claim 6, characterized in that: the drying process comprises the following steps: the drying temperature was 60 ℃ and the time was 6 hours.
8. The method for producing a hexagonal boron nitride ceramic having excellent thermal wave-transmitting properties according to claim 1, characterized in that: the process of the air pressure sintering comprises the following steps: the sintering temperature is 1650 to 2200 ℃, the pressure is 5 to 50MPa, the sintering atmosphere is nitrogen, and the time is 60 to 120 minutes.
9. The method for producing a hexagonal boron nitride ceramic having excellent heat wave-transmitting properties according to claim 8, characterized in that: the process of the air pressure sintering comprises the following steps: the sintering temperature is 1900 ℃, the pressure is 15MPa, the sintering atmosphere is nitrogen, and the time is 90 minutes.
CN202210812537.2A 2022-07-11 2022-07-11 Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance Active CN115180957B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210812537.2A CN115180957B (en) 2022-07-11 2022-07-11 Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210812537.2A CN115180957B (en) 2022-07-11 2022-07-11 Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance

Publications (2)

Publication Number Publication Date
CN115180957A CN115180957A (en) 2022-10-14
CN115180957B true CN115180957B (en) 2023-03-31

Family

ID=83516656

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210812537.2A Active CN115180957B (en) 2022-07-11 2022-07-11 Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance

Country Status (1)

Country Link
CN (1) CN115180957B (en)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100506690C (en) * 2006-09-07 2009-07-01 暨南大学 Preparation method of hexagonal boron nitride and produced hexagonal boron nitride multi-crystal powder
CN101648809B (en) * 2009-09-25 2012-06-27 哈尔滨工业大学 Boron nitride based composite ceramic wave-transparent material and preparation method thereof
CN103145112B (en) * 2013-03-29 2014-11-19 哈尔滨工业大学 BN-Si2N2O composite ceramic and preparation method thereof
CN103274696B (en) * 2013-04-19 2015-01-07 北京中材人工晶体研究院有限公司 Heat wave-transmission porous ceramic material and preparation method thereof
CN103964860B (en) * 2014-05-05 2015-09-09 哈尔滨工业大学 A kind of take Nano silica sol as the preparation method of the boron nitride-base wave-penetrating composite material of sintering aid hot pressing
CN104177091B (en) * 2014-08-11 2015-11-18 河海大学 A kind of preparation method of high-compactness hexagonal boron nitride stupalith
JP6765236B2 (en) * 2016-07-04 2020-10-07 三菱電機株式会社 Radomes for ceramic composites and flying objects
CN108640690A (en) * 2018-07-17 2018-10-12 哈尔滨工业大学 A kind of orientation heat transfer hexagonal boron nitride/cordierite textured ceramic and preparation method thereof
CN112520714A (en) * 2020-03-20 2021-03-19 山东晶亿新材料有限公司 Hexagonal boron nitride and preparation method and application thereof

Also Published As

Publication number Publication date
CN115180957A (en) 2022-10-14

Similar Documents

Publication Publication Date Title
WO2007119526A1 (en) In-line heater and method for manufacturing same
EP3915934A1 (en) High-purity low-aluminium spherical beta silicon nitride powder, manufacturing method therefor and use thereof
JPH0769731A (en) High-strength, high-density conductive ceramic
KR20170061755A (en) Alumina complex ceramics composition and manufacturing method thereof
JP7062229B2 (en) Plate-shaped silicon nitride sintered body and its manufacturing method
CN112830788B (en) Silicon nitride ceramic material and preparation method thereof
CN101734923A (en) Aluminum nitride porous ceramic and preparation method thereof
CN111320476A (en) Diamond-silicon carbide composite material, preparation method thereof and electronic equipment
CN110423122B (en) Preparation method of low-loss and high-thermal-conductivity silicon nitride ceramic
CN116462509A (en) Isostatic pressure graphite for photovoltaic and preparation method and application thereof
US3538205A (en) Method of providing improved lossy dielectric structure for dissipating electrical microwave energy
CN115180957B (en) Preparation method of hexagonal boron nitride ceramic with excellent thermal wave transmission performance
JP2007183085A (en) In-line heater and manufacturing method of the same
JPH1167427A (en) Heater component
CN111170743B (en) Silicon carbide infrared radiation ceramic material and preparation method thereof
JP3765840B2 (en) Carbon material manufacturing method
CN1489965A (en) Ceramic heating apparatus and producing method thereof
JP4490304B2 (en) Susceptor
CN113186416A (en) SiC reinforced copper-based composite material and preparation method thereof
JP2000007436A (en) Graphite material and its production
KR102555662B1 (en) Method for Preparing Silicon Nitride Sintered Body and The Silicon Nitride Sintered Body Prepared by The Same
CN109650862B (en) High-temperature-resistant boron nitride-strontium feldspar ceramic matrix composite material and preparation method thereof
CN114956833A (en) High-temperature-resistant thermal shock-resistant composite ceramic insulating material and preparation method thereof
JP2919901B2 (en) Melting crucible equipment
CN109734453B (en) Boron nitride-strontium feldspar ceramic matrix composite material for aerospace heat protection and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant