A high thermal conductivity metal ceramic material and its preparation method and application

Abstract

The present invention discloses a high thermal conductivity metal ceramic material and its preparation method and application, belonging to the technical field of metal ceramic materials. The metal ceramic material comprises porous titanium carbonitride-based ceramic particles, nickel-cobalt metal binder phase and silicon nitride whiskers, wherein the ceramic phase in the porous titanium carbonitride-based ceramic particles comprises WC, Mo2C, TaC, NbC, Cr3C2 and Ti(C,N). The preparation method comprises ball milling, granulating and carbonitriding the metal oxide raw material and carbon black to obtain porous titanium carbonitride-based ceramic particles, which are then further mixed with silicon nitride whiskers, nickel powder, cobalt powder and carbon black, pressed and sintered to obtain a high thermal conductivity metal ceramic material. While maintaining excellent antioxidant properties and high-temperature dimensional stability, the metal ceramic material also has high thermal conductivity, is particularly suitable for use with metal ceramic heat sinks, and can provide higher production efficiency and production stability for curved glass hot bending.

Description

Technical Field

[0001] The present invention relates to a metal ceramic material, in particular to a high thermal conductivity metal ceramic material for a heat spreader used in hot bending processing of curved glass of a mobile phone, and also to a preparation method thereof, belonging to the technical field of metal ceramic materials. Background Art

[0002] With the advancement of information technology and intelligent technology, the market size and product quality of glass windows have grown rapidly. The complex shapes of 3D curved glass and aspherical curved glass lend them unique applications, enabling them to create fuller displays and deliver superior visual quality. They are widely used in consumer electronics such as mobile phones, as well as in cameras for imaging applications such as security, surveillance, and autonomous vehicles. Currently, these complex glass shapes are primarily formed through cold working and hot forming processes. Hot forming is the most advanced technology for producing aspheric glass, offering low investment, short process steps, and high production efficiency. However, it also presents significant technical challenges and challenging precision requirements. The hot bending process primarily relies on a glass bending machine, and the precision of the product is directly determined by the uniformity of pressure and temperature applied to the glass during the bending process. The vapor chamber is a key component that directly applies pressure and transmits force to the glass mold. It must evenly distribute uneven pressure and heat transfer between the mold and the glass. The uniformity of heat and force transfer directly impacts the quality of the final product.

[0003] In current hot bending glass machine equipment, the heat spreader is often made of WC-based carbide with a coating. However, there are problems in use: WC itself has poor oxidation resistance and is prone to produce oxide particles on the surface of the plate, affecting the heat transfer and force transfer of the heat spreader. Because the surface needs to be coated with an anti-oxidation coating, on the one hand, the anti-oxidation coating is thin and often wears out during use. On the other hand, due to the cost, the coating is only coated on the top surface, while the bottom surface and the contact surface with the heating plate are not coated. At high temperatures, the gap between the two plates will cause a large number of oxide particles to be generated on the back of the heat spreader. Therefore, the service life of the WC-based carbide with a coating heat spreader is short, and the stability is poor during long-term high-temperature use, making it difficult to guarantee the stability of the produced glass products. Titanium carbonitride-based metal ceramics, on the other hand, have excellent oxidation resistance and thermal stability. As a heat spreader for glass hot bending machines, they can maintain high dimensional accuracy for a long time.

[0004] However, due to the inherent lower thermal conductivity of Ti(C,N) compared to WC, metal ceramics have a relatively low thermal conductivity when used as vapor chambers. Consequently, they struggle to meet the demands of some demanding equipment for hot-bent glass vapor chambers, which require high heat transfer rates and uniformity. Consequently, there is an urgent need to find a new vapor chamber material with excellent thermal conductivity, outstanding oxidation resistance, and dimensional stability even under high-temperature conditions. Summary of the Invention

[0005] In view of the technical problems in the existing technology that carbide heat spreaders used for curved glass bending have poor oxidation resistance, short life, and poor dimensional uniformity, while metal ceramic heat spreaders have low thermal conductivity and relatively poor temperature uniformity, the purpose of the present invention is to provide a high thermal conductivity metal ceramic material that maintains excellent oxidation resistance and high-temperature dimensional stability while also having high thermal conductivity. It is particularly suitable for use with metal ceramic heat spreaders and can provide higher production efficiency and production stability for curved glass bending.

[0006] Another object of the present invention is to provide a method for preparing a high thermal conductivity metal ceramic material, which is simple, low in cost, and easy to control under conditions, and is conducive to industrial production.

[0007] The third object of the present invention is to provide an application of a high thermal conductivity metal ceramic material. Based on its excellent antioxidant properties, high temperature stability and high thermal conductivity, it is used in a metal ceramic heat sink, which can provide higher production efficiency and production stability for curved glass bending.

[0008] In order to achieve the above technical objectives, the present invention provides a high thermal conductivity metal ceramic material, which comprises porous titanium carbonitride-based ceramic particles, a metal bonding phase and silicon nitride whiskers; the metal bonding phase includes nickel and cobalt; the ceramic phase in the porous titanium carbonitride-based ceramic particles includes WC, Mo2C, TaC, NbC, Cr3C2 and Ti(C,N).

[0009] The high thermal conductivity metal ceramic material provided by the present invention mainly includes porous titanium carbonitride-based ceramic particles, a metal binder phase and silicon nitride whiskers. By optimizing the ceramic phase composition, it itself has a high thermal conductivity and is endowed with excellent antioxidant properties. At the same time, by introducing silicon nitride whiskers, not only can its thermal conductivity be improved, but it can also serve as a reinforcing phase to improve its mechanical strength.

[0010] As a preferred embodiment, the porous titanium carbonitride-based ceramic particles have a particle size of 100 to 300 μm. Optimizing the particle size of the porous titanium carbonitride-based ceramic particles facilitates the formation of a continuous metal binder phase between the porous titanium carbonitride-based ceramic particles. The binder phase with a high mean free path provides a sufficient pathway for heat transfer. Furthermore, the use of porous titanium carbonitride-based ceramic particles facilitates the penetration of the metal binder phase into the pores, thereby enhancing the bond strength between the ceramic particles and the metal binder phase.

[0011] As a preferred solution, the silicon nitride whisker has a diameter of 2 to 5 μm and a length of 20 to 50 μm.

[0012] As a preferred solution, the particle size of the metal binder phase is 1 to 3 μm.

[0013] As a preferred embodiment, the high thermal conductivity cermet material comprises 65-75% by mass of porous titanium carbonitride-based ceramic particles, 0.5-2% by mass of silicon nitride whiskers, and the remainder being a metal binder phase. High thermal conductivity cermet materials have a higher metal binder phase content, which inherently has high thermal conductivity and can form a continuous state between the porous titanium carbonitride-based ceramic particles, providing a sufficient pathway for heat transfer.

[0014] As a preferred solution, the mass proportions of the various ceramic phases in the porous titanium carbonitride-based ceramic particles are: WC 25-35%, Mo2C 2-5%, TaC 0.5-3%, NbC 0.5-3%, Cr3C2 0.5-2%, and the remainder is Ti(C, N). WC and Mo2C are used to improve the wettability and interfacial bonding strength between the titanium carbonitride ceramic particles and the metal binder phase, TaC and NbC are used to improve the material's high-temperature hardness and high-temperature strength, and Cr3C2 is used to refine the grain size and enhance high-temperature corrosion resistance.

[0015] As a preferred embodiment, the metal binder phase comprises cobalt and nickel in a mass ratio of (3-5):(5-7). When cobalt and nickel are used alone as the metal binder phase, their wettability and oxidation resistance are insufficient. However, when cobalt and nickel are used together, both strength and oxidation resistance are improved.

[0016] The present invention also provides a method for preparing a high thermal conductivity metal ceramic material, which comprises the following steps:

[0017] 1) ball-milling, granulating, and carbonitriding raw materials including titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide, and carbon black to obtain porous titanium carbonitride-based ceramic particles;

[0018] 2) The porous titanium carbonitride-based ceramic particles are mixed with silicon nitride whiskers, nickel powder, cobalt powder and carbon black, pressed and sintered to obtain a ceramic material.

[0019] As a preferred embodiment, the ball milling conditions are as follows: a ball-to-material ratio of (5-8):1; a ball milling speed of 200-300 r / min; and a ball milling time of 36-60 hours. The ball milling can be wet milling, and the ball mill used is not limited. For example, a drum ball mill or a planetary ball mill can be used. Due to the large output of the drum ball mill, the drum ball mill is preferably used for ball milling.

[0020] As a preferred solution, in step 1), the amount of carbon black added should be (230-270)% of the atomic weight of the total amount of oxygen in the oxides according to the ratio of the oxides.

[0021] As a preferred solution, the conditions for the carbonitriding treatment are: heating at a heating rate of 5 to 10°C / min, first heating to 1300°C in a vacuum environment, then heating to 1400°C to 1600°C in a nitrogen environment with a pressure of 0.5 to 2MPa, keeping warm for 0.5 to 1.5h, then keeping warm for 20 to 40min in a vacuum environment, and then cooling. The carbonitriding treatment adopts a three-stage sintering process. The first stage of vacuum sintering is mainly to promote the carbonization of metal oxides. The second stage of vacuum sintering is to nitride the carbon oxides at a lower temperature and in a short time to produce carbonitrides. The third stage of vacuum sintering is to prevent the existence of unreacted carbon black. The process is accompanied by the discharge of carbon dioxide and nitrogen oxide gases, which further opens up the pore structure channels of the particles, which is conducive to improving the continuity of the bonding phase in the later sintering. The preferred vacuum environment pressure is lower than 10Pa.

[0022] As a preferred solution, the granulation can be performed by pressure spray granulation, centrifugal spray granulation, drum granulation, or sieve granulation. The particle diameter of the granulation is 120 to 500 μm, which can ensure that the particle size of the porous titanium carbonitride-based ceramic particles obtained by sintering is within the range of 100 to 300 μm.

[0023] As a preferred embodiment, the pressing pressure is 100 MPa to 150 MPa. During the pressing process, the pressing method can be mold pressing or isostatic pressing, preferably isostatic pressing, and the pressing pressure is more preferably 120 MPa to 150 MPa. Isostatic pressing is a process in which all parts are subjected to pressure, which is conducive to maintaining the spherical shape of the porous large particles.

[0024] As a preferred solution, the sintering conditions are as follows: heating at a heating rate of 5-10°C / min, first in a vacuum environment, heating to 1300°C, then using argon to conduct pressure, heating to 1400-1500°C in an argon environment at a pressure of 5-100 MPa, and maintaining the temperature for 1-2 hours. Sintering before 1300°C in a vacuum environment is conducive to the exhaust of gases from the carbon-oxygen reaction and further diffusion of the various components. After 1300°C, the use of high gas pressure squeezes the liquid metal binder phase into the interior and between the porous titanium carbonitride-based ceramic particles, which can improve the bonding strength between the metal binder phase and the ceramic particles, and is conducive to the metal binder phase forming a continuous phase, improving thermal conductivity, while also suppressing the volatilization of nitrogen.

[0025] As a preferred solution, in step 2), the amount of carbon black used is 0.2-0.6% of the total mass of the porous titanium carbonitride-based ceramic particles, silicon nitride whiskers, nickel powder, cobalt powder and carbon black. The carbon black is mainly used for carbon-oxygen reaction deoxidation during sintering.

[0026] As a preferred solution, the silicon nitride whiskers need to be pre-treated by pickling and ultrasonic cleaning to improve their bonding strength.

[0027] As a preferred embodiment, porous titanium carbonitride-based ceramic particles are mixed with silicon nitride whiskers, nickel powder, cobalt powder, and carbon black in a granulator, V-type mixer, or biconical mixer for 24 to 48 hours. During the mixing process, care should be taken to minimize crushing and avoid breaking of the porous large particles.

[0028] The present invention also provides an application of a high-thermal-conductivity metal-ceramic material for preparing a metal-ceramic vapor chamber. The high-thermal-conductivity metal-ceramic material can be used in a metal-ceramic vapor chamber, particularly a metal-ceramic vapor chamber for hot bending of curved glass in mobile phones.

[0029] The method for preparing the high thermal conductivity metal ceramic material of the present invention comprises the following steps:

[0030] (1) Preparation of porous carbonitride particles: titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled and mixed. The amount of carbon black added should be (230-270)% of the atomic weight of the total amount of oxygen in the oxide according to the ratio of the oxides. The ball milling can be carried out using a drum ball mill or a planetary ball mill. The ball milling process parameters are as follows: the ball milling medium is alcohol, the grinding balls are carbide balls, and the ball-to-material ratio is (5-8):1; the ball milling speed is 200-300 r / min, and the ball milling time is 36-60 h; after mixing, the mixture is granulated by pressure spraying, centrifugal spraying, drum granulation and sieving granulation. Particles with a diameter of 120 to 500 μm are prepared, and then placed in a sintering furnace for carbonitriding treatment. During the carbonitriding process, the temperature is increased at a heating rate of 5 to 10°C / min, and the maximum carbonitriding temperature is 1400 to 1600°C. A vacuum atmosphere with an air pressure lower than 10 Pa is used before 1300°C. A nitrogen atmosphere with an air pressure of 0.5 to 2 MPa is used from 1300°C to the maximum temperature. After the maximum temperature is kept for 0.5 to 1.5 hours, the vacuum atmosphere is switched back to the vacuum atmosphere with an air pressure lower than 10 Pa. After keeping the temperature for 20 to 40 minutes, the particles are cooled to obtain porous titanium carbonitride-based ceramic particles with a particle diameter of 100 to 300 μm.

[0031] (2) Preparation of a mixture: The large-sized porous titanium carbonitride-based ceramic particles prepared in step (1) are uniformly mixed with silicon nitride whiskers, cobalt powder, nickel powder, and carbon black that have been pretreated by pickling and ultrasonic cleaning, wherein the amount of carbon black added is 0.2 to 0.6% of the total mass of the mixture. The mixing method is mixing in a granulator, a V-type mixer, or a double-cone mixer, and the mixing time is 24 to 48 hours.

[0032] (3) Pressing: The mixture obtained in step (2) is subjected to molding or isostatic pressing at a pressing pressure of 100 MPa to 150 MPa.

[0033] (4) Sintering: The plate obtained in step (3) is sintered at a heating rate of 5 to 10°C / min. Vacuum sintering is performed before 1300°C with a vacuum degree of 0.001 to 1Pa. After 1300°C, argon gas is used to conduct pressure with a pressure of 5 to 100MPa. The final sintering temperature is 1400 to 1500°C and the sintering time is 1 to 2h. After cooling, a finished high thermal conductivity metal ceramic heat sink is obtained.

[0034] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0035] The high thermal conductivity metal ceramic material provided by the present invention can obtain a high thermal conductivity coefficient by optimizing the ceramic phase composition, adopting porous titanium carbonitride-based ceramic particles and using silicon nitride whiskers. At the same time, it has excellent oxidation resistance and high-temperature dimensional stability. It is particularly suitable for use with metal ceramic heat sinks and can provide higher production efficiency and production stability for curved glass hot bending.

[0036] The high thermal conductivity metal ceramic material provided by the present invention adopts a high proportion of metal binder phase and large-sized porous titanium carbonitride-based ceramic particles, so that the metal binder phase is distributed coherently and the mean free path is large, thereby obtaining a high thermal conductivity coefficient.

[0037] The high thermal conductivity metal ceramic material provided by the present invention adopts silicon nitride whiskers, and utilizes its pull-out and connection functions to enhance the strength of the metal ceramic heat sink and have higher resistance to high-temperature deformation. At the same time, silicon nitride whiskers have excellent thermal conductivity and can further improve the thermal conductivity of the metal ceramic material.

[0038] The preparation method of the high thermal conductivity metal ceramic material of the present invention is simple, low in cost, and easily controllable in conditions, and is conducive to industrial production.

[0039] In summary, the high thermal conductivity metal ceramic material provided by the present invention has high thermal conductivity, high strength, and high stability, and is suitable for heat spreaders used in hot bending processing of curved glass. Compared with traditional carbide heat spreaders, it has excellent antioxidant properties and good high-temperature dimensional accuracy; compared with metal ceramic heat spreaders, it has higher thermal conductivity and strength. DETAILED DESCRIPTION

[0040] The following specific examples are intended to further illustrate the present invention, rather than to limit the scope of protection of the claims.

[0041] Performance test: Flexural strength standard GB / T 3851-2015.

[0042] Fracture toughness standard GB / T 33819-2017.

[0043] Oxidation weight gain per unit area at 800℃ within 10h: in accordance with standard GB / T 13303-1991.

[0044] The thermal conductivity was measured using a laser flash thermal conductivity analyzer.

[0045] Example 1

[0046] Porous titanium carbonitride-based ceramic particles (accounting for 65% of the metal ceramic vapor chamber mass), the ceramic phase weight percentages in the porous titanium carbonitride-based ceramic particles are WC 25%, Mo2C 5%, TaC 0.5%, NbC 3%, Cr3C2 2%, and the remainder is Ti(C,N), for a total weight of 100%. When preparing the titanium carbonitride-based ceramic particles, the metal oxide powder raw materials such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide are measured according to the mass percentage of the corresponding metal elements in the ceramic particles.

[0047] Metal bonding phase (accounting for 33% of the mass of the metal ceramic heat sink), wherein the mass ratio of cobalt to nickel is 3:7.

[0048] Silicon nitride whiskers (accounting for 2% of the mass of the metal ceramic heat sink), with a size distribution of 2 to 5 μm in diameter and 20 to 50 μm in length.

[0049] (1) Preparation of porous carbonitride particles: titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled and mixed. The amount of carbon black added is 240% of the atomic weight of the total amount of oxygen in the oxide. The ball milling is carried out using a drum ball mill. The ball milling process parameters are as follows: the ball milling medium is alcohol (anhydrous ethanol), the grinding balls are carbide balls, the ball-to-material ratio is 5:1; the ball milling speed is 200 r / min, and the ball milling time is 60 h; after mixing, the particles with a diameter of 120 to 5 are prepared by drum granulation. 00μm particles are placed in a sintering furnace for carbonitriding treatment. During the carbonitriding process, the temperature is increased at a heating rate of 5℃ / min, and the maximum temperature is 1400℃. A vacuum atmosphere with an air pressure of 8Pa is used before 1300℃. A nitrogen atmosphere with an air pressure of 2MPa is used from 1300℃ to the maximum temperature. After the maximum temperature is kept for 1h, the vacuum atmosphere is switched back to the air pressure of 8Pa. After keeping the temperature for 20min, the porous titanium carbonitride-based ceramic particles with a particle diameter of 100-300μm are obtained.

[0050] (2) Preparation of the mixture: The large-sized porous titanium carbonitride-based ceramic particles prepared in step (1) are uniformly mixed with silicon nitride whiskers, cobalt powder, nickel powder, and carbon black that have been pretreated by acid washing and ultrasonic cleaning. The amount of carbon black added is 0.2% of the total mass of the mixture. The mixing method is mixing in a V-type mixer for 24 hours.

[0051] (3) Pressing: The mixture obtained in step (2) was isostatically pressed at a pressing pressure of 100 MPa.

[0052] (4) Sintering: The plate obtained in step (3) is sintered at a heating rate of 10°C / min. Vacuum sintering is performed before 1300°C with a vacuum degree of 1Pa. After 1300°C, argon gas is used to conduct pressure with a pressure of 10MPa. The final sintering temperature is 1400°C and the sintering time is 2h. After cooling, a finished high thermal conductivity metal ceramic heat sink is obtained.

[0053] Metal ceramic vapor chamber performance test: hardness HRA 88.0, bending strength 2800MPa, fracture toughness 14MPa·m 1 / 2 , thermal conductivity 50W / m·K, oxidation weight per unit area increased by 4×10 at 800℃ within 10h -3 mg / mm 2 .

[0054] Example 2

[0055] The porous titanium carbonitride-based ceramic particles (accounting for 68% of the mass of the metal ceramic vapor chamber) and the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles. The mass percentage of each ceramic phase in the porous titanium carbonitride-based ceramic particles is WC 35%, Mo2C 2%, TaC 3%, NbC 0.5%, Cr3C2 0.5%, and the remainder is Ti(C,N), for a total mass of 100%. When preparing the titanium carbonitride-based ceramic particles, the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles.

[0056] Metal bonding phase (accounting for 31.5% of the mass of the metal ceramic heat sink), wherein the mass ratio of cobalt to nickel is 5:5.

[0057] Silicon nitride whiskers (accounting for 0.5% of the mass of the metal ceramic heat sink), with a size distribution of 2 to 5 μm in diameter and 20 to 50 μm in length.

[0058] (1) Preparation of porous carbonitride particles: titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled and mixed. The amount of carbon black added is 240% of the atomic weight of the total amount of oxygen in the oxide. The ball milling is carried out using a drum ball mill. The ball milling process parameters are as follows: the ball milling medium is alcohol (anhydrous ethanol), the grinding balls are carbide balls, the ball-to-material ratio is 8:1; the ball milling speed is 300 r / min, and the ball milling time is 36 h; after mixing, the particles with a diameter of 120 to 500 mm are prepared by drum granulation. μm particles are placed in a sintering furnace for carbonitriding treatment. During the carbonitriding process, the temperature is increased at a heating rate of 8°C / min, and the maximum temperature is 1600°C. A vacuum atmosphere with an air pressure of 8Pa is used before 1300°C. A nitrogen atmosphere with an air pressure of 0.5MPa is used from 1300°C to the maximum temperature. After the maximum temperature is maintained for 0.5h, the vacuum atmosphere is switched back to the air pressure of 8Pa. After maintaining the temperature for 40min, the porous titanium carbonitride-based ceramic particles with a particle diameter of 100 to 300μm are obtained.

[0059] (2) Preparation of the mixture: The large-sized porous titanium carbonitride-based ceramic particles prepared in step (1) are uniformly mixed with silicon nitride whiskers, cobalt powder, nickel powder, and carbon black that have been pretreated by acid washing and ultrasonic cleaning. The amount of carbon black added is 0.6% of the total mass of the mixture. The mixing method is mixing in a V-type mixer for 48 hours.

[0060] (3) Pressing: The mixture obtained in step (2) is isostatically pressed at a pressing pressure of 150 MPa.

[0061] (4) Sintering: The plate obtained in step (3) is sintered at a heating rate of 8°C / min. Vacuum sintering is performed before 1300°C with a vacuum degree of 0.5 Pa. After 1300°C, argon gas is used to conduct pressure with a pressure of 95 MPa. The final sintering temperature is 1500°C and the sintering time is 1 hour. After cooling, a finished high thermal conductivity metal ceramic heat sink is obtained.

[0062] Metal ceramic vapor chamber performance test: hardness HRA90.3, bending strength 2730MPa, fracture toughness 13MPa·m 1 / 2 , thermal conductivity 47W / m·K, oxidation weight per unit area increased by 3.5×10 at 800℃ within 10h -3 mg / mm 2 .

[0063] Example 3

[0064] The porous titanium carbonitride-based ceramic particles (accounting for 70% of the mass of the metal ceramic vapor chamber) and the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles. The mass percentage of each ceramic phase in the porous titanium carbonitride-based ceramic particles is WC 30%, Mo2C 3%, TaC2%, NbC2%, Cr3C21%, and the remainder is Ti(C,N), for a total mass of 100%. When preparing the titanium carbonitride-based ceramic particles, the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles.

[0065] Metal binder phase (accounting for 29% of the mass of the metal ceramic heat sink), wherein the mass ratio of cobalt to nickel is 4:6.

[0066] Silicon nitride whiskers (accounting for 1% of the mass of the metal ceramic heat sink), with a size distribution of 3 to 4 μm in diameter and 30 to 40 μm in length.

[0067] (1) Preparation of porous carbonitride particles: titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled and mixed. The amount of carbon black added is 240% of the atomic weight of the total amount of oxygen in the oxide. The ball milling is carried out using a drum ball mill. The ball milling process parameters are as follows: the ball milling medium is alcohol (anhydrous ethanol), the grinding balls are carbide balls, the ball-to-material ratio is 6:1; the ball milling speed is 250 r / min, and the ball milling time is 50 h; after mixing, the particles with a diameter of 200 to 4 are prepared by drum granulation. 00μm particles are placed in a sintering furnace for carbonitriding treatment. During the carbonitriding process, the temperature is increased at a heating rate of 8℃ / min, and the maximum temperature is 1500℃. A vacuum atmosphere with an air pressure of 5Pa is used before 1300℃. A nitrogen atmosphere with an air pressure of 1MPa is used from 1300℃ to the maximum temperature. After the maximum temperature is kept for 1h, the vacuum atmosphere is switched back to the air pressure of 5Pa. After keeping the temperature for 30min, the particles are cooled to obtain porous titanium carbonitride-based ceramic particles with a particle diameter of 150-220μm.

[0068] (2) Preparation of the mixture: The large-sized porous titanium carbonitride-based ceramic particles prepared in step (1) are uniformly mixed with silicon nitride whiskers, cobalt powder, nickel powder, and carbon black that have been pretreated by acid washing and ultrasonic cleaning. The amount of carbon black added is 0.4% of the total mass of the mixture. The mixing method is mixing in a V-type mixer for 30 hours.

[0069] (3) Pressing: The mixture obtained in step (2) is subjected to isostatic pressing at a pressing pressure of 120 MPa.

[0070] (4) Sintering: The plate obtained in step (3) is sintered at a heating rate of 8°C / min. Vacuum sintering is performed before 1300°C with a vacuum degree of 0.5 Pa. After 1300°C, argon gas is used to conduct pressure with a pressure of 50 MPa. The final sintering temperature is 1450°C and the sintering time is 1.5 h. After cooling, a finished high thermal conductivity metal ceramic heat sink is obtained.

[0071] Metal ceramic vapor chamber performance test: hardness HRA 92.3, flexural strength 2630MPa, fracture toughness 12MPa·m 1 / 2 , thermal conductivity 43W / m·K, oxidation weight per unit area increased by 2.2×10 at 800℃ within 10h -3 mg / mm 2 .

[0072] Example 4

[0073] The porous titanium carbonitride-based ceramic particles (accounting for 75% of the mass of the metal ceramic vapor chamber) and the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles. The mass percentage of each ceramic phase in the porous titanium carbonitride-based ceramic particles is WC 30%, Mo2C 3%, TaC2%, NbC2%, Cr3C21%, and the remainder is Ti(C,N), for a total mass of 100%. When preparing the titanium carbonitride-based ceramic particles, the metal oxide powder raw materials, such as titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, and chromium oxide, are measured according to the mass percentage of the corresponding metal elements in the ceramic particles.

[0074] Metal binder phase (accounting for 24% of the mass of the metal ceramic heat sink), wherein the mass ratio of cobalt to nickel is 4:6.

[0075] Silicon nitride whiskers (accounting for 1% of the mass of the metal ceramic heat sink), with a size distribution of 3 to 4 μm in diameter and 30 to 40 μm in length.

[0076] (1) Preparation of porous carbonitride particles: titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled and mixed. The amount of carbon black added is 240% of the atomic weight of the total amount of oxygen in the oxide. The ball milling is carried out using a drum ball mill. The ball milling process parameters are as follows: the ball milling medium is alcohol (anhydrous ethanol), the grinding balls are carbide balls, the ball-to-material ratio is 7:1; the ball milling speed is 250 r / min, and the ball milling time is 45 h; after mixing, the particles with a diameter of 200 to 40 mm are prepared by drum granulation. The particles were sized at 0 μm and then placed in a sintering furnace for carbonitriding treatment. During the carbonitriding process, the temperature was increased at a heating rate of 8 °C / min, and the maximum temperature was 1550 °C. A vacuum atmosphere with a pressure of 5 Pa was used before 1300 °C. A nitrogen atmosphere with a pressure of 1.5 MPa was used from 1300 °C to the maximum temperature. After the maximum temperature was kept for 1 hour, the vacuum atmosphere was switched back to a pressure of 5 Pa. After keeping the temperature for 30 minutes, the particles were cooled to obtain porous titanium carbonitride-based ceramic particles with a particle diameter of 150 to 220 μm.

[0077] (2) Preparation of the mixture: The large-sized porous titanium carbonitride-based ceramic particles prepared in step (1) are uniformly mixed with silicon nitride whiskers, cobalt powder, nickel powder, and carbon black that have been pretreated by acid washing and ultrasonic cleaning. The amount of carbon black added is 0.4% of the total mass of the mixture. The mixing method is mixing in a V-type mixer for 30 hours.

[0078] (3) Pressing: The mixture obtained in step (2) is isostatically pressed at a pressing pressure of 130 MPa.

[0079] (4) Sintering: The plate obtained in step (3) is sintered at a heating rate of 8°C / min. Vacuum sintering is performed before 1300°C with a vacuum degree of 0.5 Pa. After 1300°C, argon gas is used to conduct pressure with a pressure of 60 MPa. The final sintering temperature is 1450°C and the sintering time is 1 hour. After cooling, a finished high thermal conductivity metal ceramic heat sink is obtained.

[0080] Metal ceramic vapor chamber performance test: hardness HRA 92.7, bending strength 2560MPa, fracture toughness 12MPa·m 1 / 2 , thermal conductivity 41W / m·K, oxidation weight per unit area increased by 2×10 at 800℃ within 10h -3 mg / mm 2 .

[0081] Comparative Example 1

[0082] Compared with Example 4, the only difference is that in the process of preparing porous carbonitride particles in step (1): particles with a diameter of 50 to 100 μm are prepared, and finally porous titanium carbonitride-based ceramic particles with a particle diameter of 20 to 60 μm are obtained.

[0083] Metal ceramic vapor chamber performance test: hardness HRA 80.1, flexural strength 2460MPa, fracture toughness 10MPa·m 1 / 2 , thermal conductivity 28W / m·K, oxidation weight per unit area increased by 8×10 at 800℃ within 10h -3 mg / mm 2 .

[0084] Comparative Example 2

[0085] Compared with Example 4, the only differences are the metal binder phase (accounting for 18% of the mass of the metal ceramic vapor chamber), porous titanium carbonitride-based ceramic particles (accounting for 81% of the mass of the metal ceramic vapor chamber), and silicon nitride whiskers (accounting for 1% of the mass of the metal ceramic vapor chamber);

[0086] Metal ceramic vapor chamber performance test: hardness HRA93.0, bending strength 1850MPa, fracture toughness 7MPa·m 1 / 2 , thermal conductivity 32W / m·K, oxidation weight per unit area increased by 7×10 at 800℃ within 10h -3 mg / mm 2 .

[0087] Comparative Example 3

[0088] Compared with Example 4, the only difference is the metal binder phase (accounting for 28% of the mass of the metal ceramic heat sink) and the porous titanium carbonitride-based ceramic particles (accounting for 72% of the mass of the metal ceramic heat sink);

[0089] Metal ceramic vapor chamber performance test: hardness HRA79, bending strength 2870MPa, fracture toughness 16MPa·m 1 / 2 , thermal conductivity 42W / m·K, oxidation weight per unit area increased by 8×10 at 800℃ within 10h -3 mg / mm 2 As a heat spreader, the wear resistance is insufficient, and the lower surface will be scratched by the mold after long-term use, and the high plane accuracy will be lost.

Claims

1. A method for preparing a high thermal conductivity metal ceramic material, characterized in that: The following steps are involved: 1) raw materials including titanium oxide, tungsten oxide, molybdenum oxide, tantalum oxide, niobium oxide, chromium oxide and carbon black are ball-milled, granulated and carbonitrided to obtain porous titanium carbonitride-based ceramic particles; 2) The porous titanium carbonitride-based ceramic particles are mixed with silicon nitride whiskers, nickel powder, cobalt powder and carbon black, and then pressed and sintered to obtain a high thermal conductivity metal ceramic material; The high thermal conductivity metal ceramic material comprises porous titanium carbonitride-based ceramic particles, a metal binder phase and silicon nitride whiskers; The metal binder phase includes nickel and cobalt; The ceramic phases in the porous titanium carbonitride-based ceramic particles are WC, Mo2C, TaC, NbC, Cr3C2 and Ti(C,N); The particle size of the porous titanium carbonitride-based ceramic particles is 100-300 μm; In the high thermal conductivity metal ceramic material, the mass proportion of porous titanium carbonitride-based ceramic particles is 65-75%, the mass proportion of silicon nitride whiskers is 0.5-2%, and the rest is a metal bonding phase.

2. The method for preparing a high thermal conductivity metal ceramic material according to claim 1, characterized in that: The silicon nitride whiskers have a diameter of 2 to 5 μm and a length of 20 to 50 μm; The particle size of the metal binder phase is 1-3 μm.

3. The method for preparing a high thermal conductivity metal-ceramic material according to claim 1, wherein: The mass proportions of the ceramic phases in the porous titanium carbonitride-based ceramic particles are: WC 25-35%, Mo2C 2-5%, TaC 0.5-3%, NbC 0.5-3%, Cr3C2 0.5-2%, and the rest is Ti(C, N).

4. The method for preparing a high thermal conductivity metal ceramic material according to claim 2, wherein: The metal bonding phase is composed of cobalt and nickel in a mass ratio of (3-5): (5-7).

5. The method for preparing a high thermal conductivity metal ceramic material according to claim 1, wherein: The ball milling conditions are as follows: the ball milling medium is alcohol, the ball-to-material ratio is (5-8):1; the ball milling speed is 200-300 r / min, and the ball milling time is 36-60 h.

6. The method for preparing a high thermal conductivity metal ceramic material according to claim 1, characterized in that: The carbonitriding treatment conditions are as follows: heating at a heating rate of 5-10°C / min, first heating to 1300°C in a vacuum environment, then heating to 1400°C-1600°C in a nitrogen environment with a pressure of 0.5-2 MPa, keeping warm for 0.5-1.5 hours, then keeping warm for 20-40 minutes in a vacuum environment, and then cooling.

7. The method for preparing a high thermal conductivity metal-ceramic material according to claim 1, characterized in that: The pressing pressure is 100MPa to 150MPa; The sintering conditions are as follows: heating at a heating rate of 5-10°C / min, first heating to 1300°C in a vacuum environment, then conducting pressure with argon, heating to 1400°C-1500°C in an argon environment with a pressure of 5-100 MPa, and keeping warm for 1-2 hours.