CN115536371A - Preparation method of high-strength 96 aluminum oxide ceramic - Google Patents

Preparation method of high-strength 96 aluminum oxide ceramic Download PDF

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CN115536371A
CN115536371A CN202211227492.9A CN202211227492A CN115536371A CN 115536371 A CN115536371 A CN 115536371A CN 202211227492 A CN202211227492 A CN 202211227492A CN 115536371 A CN115536371 A CN 115536371A
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box body
alumina
strength
alumina powder
alumina ceramic
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CN115536371B (en
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杨大胜
施纯锡
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FUJIAN HUAQING ELECTRONIC MATERIAL TECHNOLOGY CO LTD
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FUJIAN HUAQING ELECTRONIC MATERIAL TECHNOLOGY CO LTD
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Abstract

The invention relates to the technical field of ceramic substrates, and provides a preparation method of high-strength 96 aluminum oxide ceramic, which solves the problems of low thermal conductivity and poor mechanical strength of the existing 96 ceramic. The method comprises the following steps: preparing materials: the alumina ceramic is prepared from the following components in percentage by mass: 96% of alumina powder, 1.8-3% of composite sintering aid and the balance of yttrium fluoride, wherein the composite sintering aid is Cr 2 O 3 -a BaO-ZnO ternary system; (2) ball milling and vacuum defoaming; (3) tape casting; (4) rubber discharge: placing the green sheet obtained by tape casting into a glue discharging device for glue discharging; and (5) sintering. Under the condition of not increasing the cost, the formula and the process of the alumina ceramic are optimized, and the heat-conducting property and the mechanical property of the alumina ceramic are improved.

Description

Preparation method of high-strength 96 aluminum oxide ceramic
Technical Field
The invention relates to the technical field of ceramic substrates, in particular to a preparation method of high-strength 96 aluminum oxide ceramic.
Background
The electronic packaging substrate is an important component of an electronic component and plays roles in heat dissipation, insulation protection, structural packaging support and the like of various electronic components. The electronic packaging substrate is mainly divided into three types, namely a polymer plastic substrate, a metal substrate and a ceramic substrate, and due to the fact that polymer materials have the inherent characteristic of extremely low thermal conductivity, the metal substrate materials are high in thermal conductivity but are conductive materials, an insulating layer is required to be additionally added when the chip is packaged, the process cost is greatly improved, and therefore the use of the polymer plastic substrate and the metal substrate is greatly limited. The ceramic material has the properties of high thermal conductivity, good heat resistance, high insulation, high strength, thermal matching with a chip material and the like, is very suitable for serving as a power device packaging substrate, and is widely applied to the fields of semiconductor illumination, laser and optical communication, aerospace, automotive electronics, deep sea drilling and the like at present.
A common ceramic substrate is Al 2 O 3 The aluminum oxide ceramic substrate has good mechanical strength, stability, high pressure resistance and insulativity although the thermal conductivity is relatively low, the raw material source is rich, the production process is relatively simple, the preparation cost is far lower than that of other ceramic substrates, the aluminum oxide ceramic substrate is the ceramic substrate material which is most widely applied at present, and the market share exceeds 80%.
The alumina ceramics are generally classified according to the content of alumina in ingredients or porcelain bodies, and can be classified into 99 porcelain, 96 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties. Most of the alumina substrates on the market at present are mainly made of 96 porcelain (the content of alumina is 96%), and the alumina substrates are widely applied to the fields of thick film integrated circuits, LED packaging and the like. In order to improve the overall performance of alumina ceramics, the industry generally adopts a mode of increasing the content of alumina. However, with the increase of the content of alumina, not only the raw material cost is increased, but also sintering can be completed at a higher temperature, so that the requirements on equipment are stricter, and the energy consumption is higher.
The existing alumina ceramic substrate still has the problems of low thermal conductivity, poor mechanical strength and the like, and how to improve the thermal conductivity and the mechanical property of the alumina ceramic substrate on the premise of not increasing the content of alumina is a research focus of research personnel in the industry at the present stage. For example, chinese patent No. CN 201690900.3 discloses a high-performance 96 alumina ceramic and a preparation method thereof, comprising the following steps: (1) mixing powder; (2) dry pressing and forming; and (3) pressureless sintering. By introducing alpha-Al 2 O 3 Adding a proper amount of SiO 2 MgO and CaO, and the adjustment of preparation process parameters, the insulating property, the dielectric strength and the force of the prepared 96 alumina ceramics are obviously improvedChemical properties and thermal conductivity. The volume resistivity of the prepared 96 alumina ceramic in the environment with room temperature and 25 percent of humidity can reach 7 multiplied by 10 14 Omega cm, and its volume resistivity can be maintained at 10 at room temperature and 70% humidity 12 More than the order of magnitude of (A), and the volume resistivity can reach 10 when the temperature is 600 DEG C 8 More than the order of magnitude; the dielectric strength of 96 aluminum oxide ceramics is up to 30kV/mm under the condition of room temperature, the thermal conductivity is up to 26.4W/m.K, the bending strength is up to about 400MPa, and the Vickers hardness is up to 14GPa.
Disclosure of Invention
Therefore, aiming at the above content, the invention provides a preparation method of high-strength 96 alumina ceramic, which solves the problems that the existing alumina ceramic has low thermal conductivity and poor mechanical strength and is difficult to meet the higher requirement on electronic packaging materials. Under the condition of not increasing the cost, the formula and the process of the alumina ceramic are optimized, and the heat-conducting property and the mechanical property of the alumina ceramic are improved.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a preparation method of high-strength 96 alumina ceramic comprises the following steps:
(1) Preparing materials:
the alumina ceramic is prepared from the following components in percentage by mass: 96% of alumina powder, 1.8-3% of composite sintering aid and the balance of yttrium fluoride, wherein the alumina powder is alpha-alumina, and the composite sintering aid is Cr 2 O 3 -a BaO-ZnO ternary system;
weighing the raw material components according to the proportion for later use;
(2) Ball milling and vacuum defoaming:
adding alumina powder, a composite sintering aid and yttrium fluoride into a ball mill, then adding a solvent, a dispersing agent and a defoaming agent to perform primary ball milling for 8-12 h, and then adding an adhesive and a plasticizer to perform secondary ball milling for 15-25 h;
performing vacuum defoaming on the ball-milled materials by using a vacuum defoaming machine to obtain ceramic slurry;
(3) Tape casting:
casting and molding the ceramic slurry obtained in the step (2) on a casting machine to obtain a green tape, and then placing the green tape on a sheet punching machine for punching to obtain a green sheet with the required shape and size;
(4) Rubber discharging:
placing the green sheets into a glue discharging device for glue discharging, and removing organic matters in the green sheets;
the glue discharging device comprises a glue discharging box, the glue discharging box comprises an outer box body, an inner box body and a middle box body clamped between the outer box body and the inner box body, a heat insulating layer is arranged between the outer box body and the middle box body, an air flowing cavity is arranged between the middle box body and the inner box body, an air heater is arranged at the bottom of the outer box body, a hot air pipe is fixedly connected with the output end of the air heater, the hot air pipe penetrates through the outer box body and extends into the air flowing cavity, a driving motor is arranged at the top of the outer box body, a rotating shaft is fixedly connected with the output end of the driving motor, a plurality of object placing units are sleeved on the rotating shaft, each object placing unit forms an object placing groove for placing a green blank sheet through a partition plate, vent holes are formed in the bottom of the object placing groove, vent holes are formed in the side wall of the inner box body, and the vent holes are strip-shaped, the area of the vent is gradually increased from top to bottom, the top of the inner box body is fixedly connected with a rubber discharge pipe, one end of the rubber discharge pipe sequentially penetrates through the outer box body, the heat preservation layer, the middle box body and the air flow cavity and extends into the inner box body, the other end of the rubber discharge pipe is fixedly connected with a recovery tank, the outer wall of the rubber discharge pipe above the recovery tank is fixedly connected with a cooling mechanism, the rubber discharge pipe between the cooling mechanism and the recovery tank is connected with a first exhaust pipe, one side of the first exhaust pipe, away from the rubber discharge box, is provided with a purification mechanism, the first exhaust pipe is connected with the bottom of the side wall of the purification mechanism, the top of the purification mechanism is fixedly connected with a second exhaust pipe, a filter plate is arranged in the purification mechanism, and an active carbon adsorption plate is arranged above the filter plate;
(5) And (3) sintering:
and (3) placing the green compact sheet after the glue is removed in a sintering furnace, heating to 900-1000 ℃ at the speed of 5-8 ℃/min, then heating to 1540-1580 ℃ at the speed of 2-4 ℃/min, preserving the heat for 8-15 h, and taking out after cooling to obtain the 96 alumina ceramic.
The further improvement is that: one end of the rotating shaft, which is far away from the driving motor, is rotatably connected with a bearing seat, and the bearing seat is fixedly connected to the bottom of the inner wall of the inner box body.
The further improvement is that: the filter plate and the activated carbon adsorption plate are detachably arranged in the purification mechanism.
The further improvement is that: the lateral wall of purifying mechanism has seted up the mounting groove, the both sides of filter and active carbon adsorption plate are equipped with the fixed block with mounting groove looks adaptation.
The further improvement is that: the cooling mechanism is a cooling pipe, and the cooling pipe is spirally wound on the outer wall of the rubber discharge pipe.
The further improvement is that: the specific technological parameters of the rubber discharge are as follows: the glue discharging temperature is 520-580 ℃, and the glue discharging time is 2-4 h.
The further improvement is that: the dispersing agent is prepared by compounding polyethyleneimine and sodium alkyl benzene sulfonate according to the mass ratio of 1.5.
The further improvement is that: the addition amounts of the solvent, the dispersant, the defoaming agent, the adhesive and the plasticizer are 50-80%, 0.4-2%, 0.2-0.5%, 5-10% and 1-4% in sequence based on 100% of the mass of the alumina powder.
The further improvement is that: cr in the composite sintering aid 2 O 3 42 to 50 percent of the total amount of the zinc oxide, 14 to 22 percent of BaO and 30 to 40 percent of ZnO.
The further improvement is that: the alumina powder consists of micron-level alumina powder and nanometer-level alumina powder, wherein the micron-level alumina powder accounts for 90-99%, the median particle size of the micron-level alumina powder is 1-3 mu m, and the median particle size of the nanometer-level alumina powder is 60-90 nm.
By adopting the technical scheme, the invention has the beneficial effects that:
the degumming treatment is an important process in the production process of the alumina ceramic substrate, can effectively remove organic matters in the green sheet, and avoids the defects of holes, cracks and the like caused by decomposition of organic matters during high-temperature sintering due to the residual organic matters, thereby influencing the comprehensive performance of the alumina ceramic product. The existing glue discharging device is unreasonable in structural design, often poor in glue discharging uniformity, inconsistent in glue discharging degree of different positions, low in glue discharging efficiency, and incapable of fully discharging organic matters in green sheets, so that the produced alumina ceramic has performance defects. The application provides a follow-on binder removal device, flows the intracavity with the leading-in air of hot-air through air heater and hot-blast main, enters into the interior box by the vent again, carries out the binder removal to the green body piece. The hot air is continuously contacted with the green sheets in the upward movement process to remove organic matters in the green sheets, so that the lower hot air tends to have the largest glue removal amount, and the glue removal degrees of the green sheets at different positions are inconsistent. The area through setting up the vent is by last crescent down for the hot-air binder removal volume that box keeps unanimous basically in the different positions got into, can improve binder removal's homogeneity and binder removal efficiency. Through the cooperation of putting thing unit, driving motor, pivot, reach good binder removal effect. When the driving motor works, the rotating shaft starts to rotate to drive the object placing unit to rotate along with the rotating shaft, and the green sheets are fully contacted with hot air in the rotating process, so that the glue discharging efficiency is improved; the uniformity of the discharged glue can be improved through rotation. In addition, the volatilization and discharge of organic matters in the green sheets can be accelerated by the centrifugal force generated by rotation, so that the full glue discharge is realized, and the glue discharge time is shortened. The setting of air vent has further improved the area of contact of unburned bricks piece with the hot-air, improves the binder removal efficiency. The organic matter forms colloid steam and is discharged from the rubber discharge pipe along with hot air after the rubber discharge treatment, and the colloid steam is condensed into liquid and falls into the recovery tank after passing through the cooling mechanism, thereby realizing the recovery of the organic matter and avoiding air pollution caused by direct discharge. Poisonous and harmful gas generated in the glue discharging process enters the purifying mechanism along with hot air through the first exhaust pipe, and dust and other impurities are effectively filtered and removed through the filter plate; through setting up the active carbon adsorption board, adsorb the purification to poisonous and harmful gas, avoid air pollution. Through the setting of mounting groove and fixed block, conveniently clear up, change filter and active carbon adsorption plate.
The sintering temperature of the alumina ceramic can be reduced by adding the sintering aid, and MgO-SiO is commonly used at home at present 2 -Al 2 O 3 And CaO-MgO-SiO 2 -Al 2 O 3 The alumina ceramic prepared by the sintering aid system has good mechanical property and electrical property, but the sintering temperature is still higher than 1600 ℃, and the production cost is high. The invention adopts Cr 2 O 3 the-BaO-ZnO ternary system sintering aid can remarkably reduce the sintering temperature, and the sintered alumina ceramic finished product has high density, excellent mechanical property and good thermal conductivity. The analysis conjectures that the main reasons are: firstly, the sintering aid reacts with the alumina matrix to generate solid solution, so that the crystal lattice is distorted, the diffusion rate is increased, and the sintering temperature of the alumina ceramic is reduced. The composite sintering aid contains variable valence metal ions, can form different types of solid solutions with alumina, enhances lattice distortion, promotes lattice activation, and further improves the sintering performance of alumina ceramics. And secondly, the sintering aid and the alumina matrix form a liquid phase at high temperature, so that the migration and diffusion of mass points in the sintered body are promoted, and the sintering performance of the alumina ceramic is improved. By adding yttrium fluoride, a more stable eutectic liquid phase is formed in the sintering process, and meanwhile, the diffusion and bonding among particles are promoted, and the density of the alumina ceramic is improved. Finally, the sintering aid and the alumina matrix generate a second phase substance at high temperature, so that the normal growth of crystal grains is promoted, and the abnormal growth of the crystal grains is effectively inhibited; and the abnormal growth of the crystal grain boundary migration rate is hindered, the amount of pores in the crystal grains is reduced, and the density of the alumina ceramic is improved. Along with the increase of the compactness and the improvement of the grain size and the grain boundary strength, the bending strength of the alumina ceramic is obviously increased under the combined action. The aluminum oxide ceramic prepared by the method has high bending strength which can reach more than 560MPa, can bear severe working environments such as stronger vibration, larger external force impact and the like, and widens the application range of the aluminum oxide ceramic productA scene is used.
Drawings
FIG. 1 is a schematic structural view of a glue discharging apparatus in embodiment 1 of the present invention;
FIG. 2 is a plan view of the center unit in example 1;
FIG. 3 is a side view of the inner case of embodiment 1;
fig. 4 is an enlarged schematic view at a in fig. 1.
Detailed Description
The following detailed description will be given with reference to specific embodiments, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.
Unless otherwise indicated, the techniques used in the examples are conventional and well known to those skilled in the art, and the reagents and products used are also commercially available. The source, trade name and if necessary the constituents of the reagent used are indicated at the first appearance.
Example 1
A preparation method of high-strength 96 alumina ceramic comprises the following steps:
(1) Preparing materials:
the alumina ceramic is prepared from the following components in percentage by mass: 96% of alumina powder, 1.8% of composite sintering aid and the balance of yttrium fluoride, wherein the alumina powder is alpha-alumina, the purity is greater than 99.9%, and the composite sintering aid specifically comprises micron-grade alumina powder and nano-grade alumina powder, wherein the micron-grade alumina powder accounts for 90%, the median particle size of the micron-grade alumina powder is 3 μm, and the median particle size of the nano-grade alumina powder is 90nm; the composite sintering aid is Cr 2 O 3 Ternary system of-BaO-ZnO, in which Cr is present 2 O 3 42% by mass, 22% by mass of BaO and 36% by mass of ZnO;
weighing the raw material components according to the proportion for later use;
(2) Ball milling and vacuum defoaming:
adding alumina powder, a composite sintering aid and yttrium fluoride into a ball mill, then adding a solvent, a dispersing agent and a defoaming agent for primary ball milling, wherein the primary ball milling time is 8 hours, then adding an adhesive and a plasticizer for secondary ball milling, wherein the secondary ball milling time is 15 hours, and the adding amounts of the solvent, the dispersing agent, the defoaming agent, the adhesive and the plasticizer are 50%, 0.4%, 0.2%, 5% and 1% in sequence by taking the mass of the alumina powder as 100%;
specifically, the solvent is a mixed solvent composed of absolute ethyl alcohol and isopropanol according to a mass ratio of 3 to 2, the dispersant is prepared by compounding polyethyleneimine and sodium alkyl benzene sulfonate according to a mass ratio of 1.5,
performing vacuum deaeration on the ball-milled materials by using a vacuum deaeration machine to obtain ceramic slurry;
(3) Tape casting:
casting and molding the ceramic slurry obtained in the step (2) on a casting machine to obtain a green tape, and then placing the green tape on a sheet punching machine for punching to obtain a green sheet with the required shape and size;
(4) Rubber discharging:
putting into the binder removal device with the unburned bricks piece and carrying out the binder removal, getting rid of the organic matter in the unburned bricks piece, the concrete technological parameter of binder removal is: the glue discharging temperature is 520 ℃, and the glue discharging time is 4 hours;
referring to fig. 1 to 4, the glue discharging device comprises a glue discharging box, the glue discharging box comprises an outer box body 1, an inner box body 2 and a middle box body 3 clamped between the outer box body 1 and the inner box body 2, a heat insulating layer 4 is arranged between the outer box body 1 and the middle box body 3, an air flowing cavity 5 is arranged between the middle box body 3 and the inner box body 2, an air heater 6 is arranged at the bottom of the outer box body 1, a hot air pipe 7 is fixedly connected to the output end of the air heater 6, the hot air pipe 7 penetrates through the outer box body and extends into the air flowing cavity 5, a driving motor 8 is arranged at the top of the outer box body 1, a rotating shaft 9 is fixedly connected to the output end of the driving motor 8, a bearing seat 10 is rotatably connected to one end of the rotating shaft 9 far away from the driving motor 8, the bearing seat 10 is fixedly connected to the bottom of the inner wall of the inner box body 2, and a plurality of object placing units 11 are sleeved on the rotating shaft 9, each object placing unit 11 forms an object placing groove 13 for placing green sheets through a partition plate 12, the bottom of the object placing groove 13 is provided with a vent hole 14, the side wall of the inner box body 2 is provided with a vent hole 15, the vent hole 15 is strip-shaped, the area of the vent hole 15 is gradually increased from top to bottom, the top of the inner box body 2 is fixedly connected with a glue discharging pipe 16, one end of the glue discharging pipe 16 sequentially penetrates through the outer box body 1, the heat preservation layer 4, the middle box body 3 and the air flow cavity 5 and extends into the inner box body 2, the other end of the glue discharging pipe 16 is fixedly connected with a recovery groove 17, the outer wall of the glue discharging pipe above the recovery groove 17 is fixedly connected with a cooling mechanism 18, the cooling mechanism 18 is a cooling pipe, the cooling pipe is spirally wound on the outer wall of the glue discharging pipe 16, and the glue discharging pipe between the cooling mechanism 18 and the recovery groove 17 is connected with a first air discharging pipe 19, a purifying mechanism 20 is arranged on one side, away from the rubber discharging box, of the first exhaust pipe 19, the first exhaust pipe 19 is connected with the bottom of the side wall of the purifying mechanism 20, a second exhaust pipe 21 is fixedly connected to the top of the purifying mechanism 20, a filter plate 22 is arranged in the purifying mechanism, an activated carbon adsorption plate 23 is arranged above the filter plate 22, a mounting groove 24 is formed in the side wall of the purifying mechanism 20, fixing blocks 25 matched with the mounting groove 24 are arranged on two sides of the filter plate and the activated carbon adsorption plate, and the filter plate and the activated carbon adsorption plate can be detachably mounted in the purifying mechanism through the matching of the mounting groove and the fixing blocks;
(5) And (3) sintering:
and (3) placing the green sheets after the glue removal into a sintering furnace, heating to 900 ℃ at the speed of 5 ℃/min, then heating to 1540 ℃ at the speed of 2 ℃/min, preserving the heat for 8h, and taking out after cooling to obtain the 96 aluminum oxide ceramic.
The alumina ceramic substrate prepared in this example was tested for the following properties: the compactness is 98.5%, the thermal conductivity is 29.2W/m.K, and the bending strength is 567MPa.
Example 2
A preparation method of high-strength 96 alumina ceramic comprises the following steps:
(1) Preparing materials:
the alumina ceramic consists ofThe components with the weight percentage are prepared as follows: 96% of alumina powder, 1.8-3% of composite sintering aid and the balance of yttrium fluoride, wherein the alumina powder is alpha-alumina and has a purity of more than 99.9%, and specifically comprises micron-level alumina powder and nanometer-level alumina powder, wherein the micron-level alumina powder accounts for 95%, the median particle size of the micron-level alumina powder is 2 μm, and the median particle size of the nanometer-level alumina powder is 75nm; the composite sintering aid is Cr 2 O 3 Ternary system of-BaO-ZnO, in which Cr is present 2 O 3 46% by mass, 14% by mass of BaO and 40% by mass of ZnO;
weighing the raw material components according to the proportion for later use;
(2) Ball milling and vacuum defoaming:
adding alumina powder, a composite sintering aid and yttrium fluoride into a ball mill, then adding a solvent, a dispersing agent and a defoaming agent for primary ball milling, wherein the primary ball milling time is 10 hours, then adding an adhesive and a plasticizer for secondary ball milling, wherein the secondary ball milling time is 20 hours, and the adding amounts of the solvent, the dispersing agent, the defoaming agent, the adhesive and the plasticizer are 65%, 1.2%, 0.4%, 8% and 2.5% in sequence based on 100% of the mass of the alumina powder;
specifically, the solvent is a mixed solvent composed of absolute ethyl alcohol and isopropanol according to a mass ratio of 3 to 2, the dispersant is prepared by compounding polyethylene imine and sodium alkyl benzene sulfonate according to a mass ratio of 2 to 1, the defoaming agent is n-octyl alcohol, the adhesive is polyvinyl butyral, and the plasticizer is dibutyl phthalate;
performing vacuum defoaming on the ball-milled materials by using a vacuum defoaming machine to obtain ceramic slurry;
(3) Tape casting:
casting and molding the ceramic slurry obtained in the step (2) on a casting machine to obtain a green tape, and then placing the green tape on a sheet punching machine for punching treatment to obtain a green sheet with a required shape and size;
(4) Rubber discharging:
putting the green body sheet into a glue discharging device for discharging glue, removing organic matters in the green body sheet, wherein the specific technological parameters of the glue discharging are as follows: the glue discharging temperature is 550 ℃, and the glue discharging time is 3 hours;
(5) And (3) sintering:
and (3) placing the green compact sheet after the glue discharging into a sintering furnace, heating to 950 ℃ at the speed of 6 ℃/min, then heating to 1560 ℃ at the speed of 3 ℃/min, preserving heat for 12h, and taking out after cooling to obtain the 96 aluminum oxide ceramic.
The alumina ceramic substrate prepared in this example was tested for the following properties: the density is 98.9 percent, the thermal conductivity is 28.4W/m.K, and the bending strength is 576MPa.
Example 3
A preparation method of high-strength 96 alumina ceramic comprises the following steps:
(1) Preparing materials:
the alumina ceramic is prepared from the following components in percentage by mass: 96% of alumina powder, 1.8-3% of composite sintering aid and the balance of yttrium fluoride, wherein the alumina powder is alpha-alumina, the purity is higher than 99.9%, and the composite sintering aid specifically comprises micron-grade alumina powder and nanometer-grade alumina powder, wherein the micron-grade alumina powder accounts for 99%, the median particle size of the micron-grade alumina powder is 1 micrometer, and the median particle size of the nanometer-grade alumina powder is 60nm; the composite sintering aid is Cr 2 O 3 Ternary system of-BaO-ZnO, in which Cr 2 O 3 50% of (A), 18% of BaO and 32% of ZnO;
weighing the raw material components according to the proportion for later use;
(2) Ball milling and vacuum defoaming:
adding alumina powder, a composite sintering aid and yttrium fluoride into a ball mill, then adding a solvent, a dispersing agent and a defoaming agent for primary ball milling, wherein the primary ball milling time is 12 hours, then adding an adhesive and a plasticizer for secondary ball milling, wherein the secondary ball milling time is 25 hours, and the adding amounts of the solvent, the dispersing agent, the defoaming agent, the adhesive and the plasticizer are 80%, 2%, 0.5%, 10% and 4% in sequence by taking the mass of the alumina powder as 100%;
specifically, the solvent is a mixed solvent composed of absolute ethyl alcohol and isopropanol according to a mass ratio of 3 to 2, the dispersant is prepared by compounding polyethylene imine and sodium alkyl benzene sulfonate according to a mass ratio of 3 to 1, the defoaming agent is n-octyl alcohol, the adhesive is polyvinyl butyral, and the plasticizer is dibutyl phthalate;
performing vacuum defoaming on the ball-milled materials by using a vacuum defoaming machine to obtain ceramic slurry;
(3) Tape casting:
casting and molding the ceramic slurry obtained in the step (2) on a casting machine to obtain a green tape, and then placing the green tape on a sheet punching machine for punching to obtain a green sheet with the required shape and size;
(4) Rubber discharging:
putting the green body sheet into a glue discharging device for discharging glue, removing organic matters in the green body sheet, wherein the specific technological parameters of the glue discharging are as follows: the glue discharging temperature is 580 ℃, and the glue discharging time is 2 hours;
(5) And (3) sintering:
and (3) placing the green compact sheet after the glue discharging into a sintering furnace, heating to 1000 ℃ at the speed of 8 ℃/min, then heating to 1580 ℃ at the speed of 4 ℃/min, preserving the heat for 15h, and taking out after cooling to obtain the 96 alumina ceramic.
The alumina ceramic substrate prepared in this example was tested for the following properties: the density is 98.2 percent, the thermal conductivity is 28.0W/m.K, and the bending strength is 561MPa.
Example 4
Compared with embodiment 1, this embodiment only adjusts part of the parameters, and the other technical solutions are the same as those of embodiment 1, and the specific parameter adjustment contents are as follows: the proportion of micron-level alumina powder is 95 percent, and Cr in the composite sintering aid 2 O 3 48% by mass, 18% by mass of BaO and 34% by mass of ZnO.
The alumina ceramic substrate prepared in this example was tested for the following properties: the density is 98.0 percent, the thermal conductivity is 27.8W/m.K, and the bending strength is 557MPa.
Example 5
Compared with embodiment 1, this embodiment only adjusts part of the parameters, othersThe technical scheme of the embodiment 1 is the same, and the specific parameter adjustment contents are as follows: the proportion of micron-level alumina powder is 99 percent, and Cr in the composite sintering aid 2 O 3 45% by mass, 17% by mass of BaO and 38% by mass of ZnO.
The alumina ceramic substrate prepared in this example was tested for the following properties: the density is 98.3 percent, the thermal conductivity is 28.5W/m.K, and the bending strength is 549MPa.
Comparative example 1
The difference from example 1 is that: the yttrium fluoride is replaced by the composite sintering aid with equal mass.
The alumina ceramic substrate prepared in this example was tested for the following properties: the compactness is 95.6 percent, the thermal conductivity is 26.5W/m.K, and the bending strength is 501MPa.
The alkaline earth metal oxide BaO in the composite sintering aid in the embodiment 1 is replaced by CaO with equal mass, or one component in the composite sintering aid is omitted, the contents of the other two components are increased in proportion, and the bending strength of the prepared alumina ceramic is lower than 480MPa.
It should be understood that the above description is only an example of the technical disclosure, and any modifications and variations made by those skilled in the art can be covered by the present disclosure, and not limited by the embodiments disclosed in the present disclosure.

Claims (10)

1. A preparation method of high-strength 96 alumina ceramics is characterized by comprising the following steps: the method comprises the following steps:
(1) Preparing materials:
the alumina ceramic is prepared from the following components in percentage by mass: 96% of alumina powder, 1.8-3% of composite sintering aid and the balance of yttrium fluoride, wherein the alumina powder is alpha-alumina, and the composite sintering aid is Cr 2 O 3 -a BaO-ZnO ternary system;
weighing the raw material components according to the proportion for later use;
(2) Ball milling and vacuum defoaming:
adding alumina powder, a composite sintering aid and yttrium fluoride into a ball mill, then adding a solvent, a dispersing agent and a defoaming agent for primary ball milling, and then adding an adhesive and a plasticizer for secondary ball milling;
performing vacuum defoaming on the ball-milled materials by using a vacuum defoaming machine to obtain ceramic slurry;
(3) Tape casting:
casting and molding the ceramic slurry obtained in the step (2) on a casting machine to obtain a green tape, and then placing the green tape on a sheet punching machine for punching treatment to obtain a green sheet with a required shape and size;
(4) Rubber discharging:
placing the green sheets into a glue discharging device for glue discharging, and removing organic matters in the green sheets;
the glue discharging device comprises a glue discharging box, the glue discharging box comprises an outer box body, an inner box body and a middle box body clamped between the outer box body and the inner box body, a heat insulating layer is arranged between the outer box body and the middle box body, an air flowing cavity is arranged between the middle box body and the inner box body, an air heater is arranged at the bottom of the outer box body, a hot air pipe is fixedly connected with the output end of the air heater, the hot air pipe penetrates through the outer box body and extends into the air flowing cavity, a driving motor is arranged at the top of the outer box body, a rotating shaft is fixedly connected with the output end of the driving motor, a plurality of object placing units are sleeved on the rotating shaft, each object placing unit forms an object placing groove for placing a green blank sheet through a partition plate, vent holes are formed in the bottom of the object placing groove, vent holes are formed in the side wall of the inner box body, and the vent holes are strip-shaped, the area of the vent is gradually increased from top to bottom, the top of the inner box body is fixedly connected with a rubber discharge pipe, one end of the rubber discharge pipe sequentially penetrates through the outer box body, the heat preservation layer, the middle box body and the air flow cavity and extends into the inner box body, the other end of the rubber discharge pipe is fixedly connected with a recovery tank, the outer wall of the rubber discharge pipe above the recovery tank is fixedly connected with a cooling mechanism, the rubber discharge pipe between the cooling mechanism and the recovery tank is connected with a first exhaust pipe, one side of the first exhaust pipe, away from the rubber discharge box, is provided with a purification mechanism, the first exhaust pipe is connected with the bottom of the side wall of the purification mechanism, the top of the purification mechanism is fixedly connected with a second exhaust pipe, a filter plate is arranged in the purification mechanism, and an active carbon adsorption plate is arranged above the filter plate;
(5) And (3) sintering:
and (3) placing the green compact sheet after the glue is removed in a sintering furnace, heating to 900-1000 ℃ at the speed of 5-8 ℃/min, then heating to 1540-1580 ℃ at the speed of 2-4 ℃/min, preserving the heat for 8-15 h, and taking out after cooling to obtain the 96 alumina ceramic.
2. The method for preparing high-strength 96 alumina ceramic according to claim 1, wherein: one end of the rotating shaft, which is far away from the driving motor, is rotatably connected with a bearing seat, and the bearing seat is fixedly connected to the bottom of the inner wall of the inner box body.
3. The method for preparing a high-strength 96 alumina ceramic according to claim 1, wherein: the filter plate and the activated carbon adsorption plate are detachably arranged in the purification mechanism.
4. The method for preparing high-strength 96 alumina ceramic according to claim 3, wherein: the lateral wall of purifying mechanism has seted up the mounting groove, the both sides of filter and active carbon adsorption plate are equipped with the fixed block with mounting groove looks adaptation.
5. The method for preparing high-strength 96 alumina ceramic according to claim 1, wherein: the cooling mechanism is a cooling pipe, and the cooling pipe is spirally wound on the outer wall of the rubber discharge pipe.
6. The method for preparing a high-strength 96 alumina ceramic according to claim 1, wherein: the specific technological parameters of the rubber discharge are as follows: the glue discharging temperature is 520-580 ℃, and the glue discharging time is 2-4 h.
7. The method for preparing a high-strength 96 alumina ceramic according to claim 1, wherein: the dispersing agent is prepared by compounding polyethyleneimine and sodium alkyl benzene sulfonate according to the mass ratio of 1.5.
8. The method for preparing a high-strength 96 alumina ceramic according to claim 1, wherein: the addition amounts of the solvent, the dispersant, the defoaming agent, the adhesive and the plasticizer are 50-80%, 0.4-2%, 0.2-0.6%, 5-10% and 1-4% in sequence based on 100% of the mass of the alumina powder.
9. The method for preparing a high-strength 96 alumina ceramic according to claim 1, wherein: cr in the composite sintering aid 2 O 3 42 to 50 percent of the total amount of the zinc oxide, 14 to 22 percent of BaO and 30 to 40 percent of ZnO.
10. The method for preparing high-strength 96 alumina ceramic according to claim 1, wherein: the alumina powder consists of micron-level alumina powder and nanometer-level alumina powder, wherein the micron-level alumina powder accounts for 90-99%, the median particle size of the micron-level alumina powder is 1-3 mu m, and the median particle size of the nanometer-level alumina powder is 60-90 nm.
CN202211227492.9A 2022-10-09 2022-10-09 Preparation method of high-strength 96 alumina ceramic Active CN115536371B (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117486620A (en) * 2023-10-30 2024-02-02 西华大学 Alumina low-temperature sintering aid, alumina ceramic material and preparation method of alumina low-temperature sintering aid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117486620A (en) * 2023-10-30 2024-02-02 西华大学 Alumina low-temperature sintering aid, alumina ceramic material and preparation method of alumina low-temperature sintering aid
CN117486620B (en) * 2023-10-30 2024-05-31 西华大学 Alumina low-temperature sintering aid, alumina ceramic material and preparation method of alumina low-temperature sintering aid

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