A metal-ceramic material for aspherical curved glass hot bending heat sink and its preparation method

Abstract

This invention discloses a metal-ceramic material for hot bending vapor chambers of aspherical curved glass and its preparation method, belonging to the technical field of metal-ceramic materials. The metal-ceramic material has a double-layer structure, with both layers containing a metal binder phase and a ceramic phase. The metal binder phase content in the top layer is lower than that in the bottom layer. The ceramic phase contains metal carbides and TiN-coated WC particles. The preparation method involves depositing a TiN coating on the surface of the WC particles, then mixing them with metal carbides and a metal binder to prepare a mixed raw material for the bottom and top layers of metal-ceramics. The mixed raw material is then pressed twice to form a complete cold-pressed blank, followed by sintering to obtain a metal-ceramic material with excellent oxidation resistance, high-temperature dimensional stability, and high thermal conductivity. This material is suitable for use in vapor chambers for hot bending of aspherical curved glass, providing higher heat transfer and force transfer stability and efficiency for precision molding of aspherical curved glass.

Description

Technical Field

[0001] This invention relates to a metal-ceramic material, specifically to a metal-ceramic material for a non-spherical curved glass hot bending heat spreader and its preparation method, belonging to the technical field of metal-ceramic materials. Background Technology

[0002] With the development of datafication and intelligence in technology, the effective and accurate capture of images is the foundation of intelligence, thus increasing the demand for clarity and accuracy in images obtained by cameras. In industries requiring imaging, such as security, surveillance, and autonomous driving, aspherical curved glass in cameras is a key component affecting image information quality and has attracted strong market attention. The production of aspherical curved glass mainly employs precision molding technology, using tungsten carbide ceramic molds to press glass that has reached its softening point (500-700℃) into the required complex shapes. This process is short, efficient, and cost-effective. However, precision molding technology is technically challenging because the molding process is carried out in a closed system within a precision molding machine. Heat and force are automatically transferred by the components, making precise control difficult. Uneven heat and force can lead to dimensional inaccuracies and poor appearance in the molded glass, thus requiring high precision and frequent maintenance of the heat and force transfer system.

[0003] In the precision molding process of aspherical curved glass, heat and force are transferred from a stainless steel heating plate. However, due to the high coefficient of thermal expansion, low thermal conductivity, and susceptibility to deformation at high temperatures, direct contact with the mold cannot guarantee the uniformity of force and heat. Therefore, a crucial component, a vapor chamber, exists between the heating plate and the mold. This vapor chamber needs to uniformly transfer the force and heat transferred from the heating plate back to the mold. It requires high thermal conductivity, high-temperature oxidation resistance, and high-temperature strength, and must not exhibit changes in dimensional accuracy during prolonged high-temperature use. Traditional vapor chambers use coated WC-based hard alloy materials. However, the poor oxidation resistance of WC leads to the shedding of yellow tungsten oxide powder, affecting glass production. Therefore, an anti-oxidation coating is often applied to the front of the vapor chamber. However, on the one hand, the high hardness of the mold makes the coating easily wear away during use; on the other hand, the lack of a coating on the back of the vapor chamber makes it prone to oxide growth, affecting flatness. Therefore, there is an urgent need to develop a vapor chamber made of a metal-ceramic material with excellent oxidation resistance and the ability to guarantee excellent dimensional accuracy over a long period.

[0004] Compared to WC-based cemented carbides, titanium carbonitride-based cermets exhibit superior oxidation resistance and higher high-temperature hardness, ensuring dimensional stability for long-term use at high temperatures. However, titanium carbonitride-based cermets also suffer from low thermal conductivity and poor thermal shock resistance, resulting in slow heat transfer under certain conditions of rapid heat absorption and release, which fails to meet their requirements. Therefore, there is an urgent need to improve their performance. Summary of the Invention

[0005] In view of the problems of poor oxidation resistance, poor dimensional stability, and short lifespan of existing heat spreaders for hot bending of aspherical curved glass, as well as the low thermal conductivity of metal ceramics, the first objective of this invention is to provide a metal ceramic material that simultaneously possesses excellent oxidation resistance, high-temperature dimensional stability, and high thermal conductivity, suitable for use in heat spreaders for hot bending of aspherical curved glass, thereby providing higher heat and force transfer stability and efficiency for precision molding of aspherical curved glass.

[0006] The second objective of this invention is to provide a method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader. This method is characterized by mild conditions, high controllability, and is conducive to industrial production.

[0007] To achieve the above technical objectives, the present invention provides a metal-ceramic material for a non-spherical curved glass hot bending heat spreader, which is composed of a top layer and a bottom layer of metal-ceramic. Both the top layer and the bottom layer of metal-ceramic contain a metal binder phase and a ceramic phase. The proportion of the metal binder phase in the top layer of metal-ceramic is lower than that in the bottom layer of metal-ceramic. The metal binder phase contains nickel and cobalt. The ceramic phase contains Mo2C, TaC, NbC, ZrC, TiN-coated WC particles and Ti(C,N).

[0008] The metal-ceramic material for hot bending vapor chambers of aspherical curved glass provided by this invention has excellent oxidation resistance, high-temperature dimensional stability and high thermal conductivity. The metal-ceramic material has a gradient structure in the thickness direction. The bottom metal-ceramic material has a relatively high proportion of metal binder phase and a relatively low proportion of ceramic phase, exhibiting high thermal conductivity and high strength. The top metal-ceramic material has a relatively low proportion of metal binder phase and a relatively high proportion of ceramic phase, exhibiting high-temperature stability and wear resistance. Furthermore, the ceramic phase used in the entire metal-ceramic material is uniformly coated with titanium carbonitride, and the metal binder phase has a large mean free path, exhibiting excellent oxidation resistance overall, which can meet the requirements of high frequency and rapid heating in precision molding.

[0009] The present invention uses TiN to coat WC particles, which mainly takes advantage of the fact that TiN is not easily dissolved in liquid phase sintering. This can effectively protect the WC particles from shrinking in size due to the dissolution process during sintering, thus ensuring the stability of the WC particles.

[0010] As a preferred embodiment, the top-layer cermet contains 8-15% by mass of a metal binder phase. It also contains 0.4-0.8% by mass of carbon black, with the remainder being a ceramic phase. The relatively low content of the metal binder phase in the top-layer cermet effectively improves the wear resistance and oxidation resistance of the cermet material.

[0011] As a preferred embodiment, the metal binder phase in the underlying cermet comprises 25-35% by mass. It also contains 0.5-0.9% by mass of carbon black, with the remainder being a ceramic phase. The high metal binder phase content in the underlying cermet allows for efficient and rapid heat conduction, thereby improving its high-temperature stability and high-temperature wear resistance.

[0012] As a preferred embodiment, the ceramic phase comprises the following components by mass percentage: Mo₂C 2–5%, TaC 1–3%, NbC 1–3%, ZrC 0.5–1.0%, TiN-coated WC particles 25–30%, and the remainder being Ti(C,N). Molybdenum carbide is used to improve the wettability between titanium carbonitride and the metal binder phase; tantalum carbide and niobium carbide are used to enhance the high-temperature performance of the material; zirconium carbide is mainly used to refine the grains and improve the oxidation resistance of the material; and TiN-coated WC particles are mainly used to maintain the crystal integrity of WC and improve the thermal conductivity of the material.

[0013] As a preferred embodiment, the mass percentage composition of cobalt and nickel in the metal binder phase is (30-70):(30-70). When cobalt and nickel are used alone as the metal binder phase, their wettability and oxidation resistance are insufficient; however, when used together, both strength and oxidation resistance are improved.

[0014] As a preferred embodiment, the size of the TiN-coated WC particles is 32–65 μm, and the TiN coating thickness is 2–5 μm. This invention utilizes large-particle TiN coating on WC particles. The large-sized WC particles provide excellent continuous heat conduction channels, which is more conducive to improving thermal conductivity and also provides higher dimensional stability. Furthermore, the addition of conventional WC particles can easily lead to a decrease in oxidation resistance, while coating the WC particle surface with TiN can protect them and ensure the material's oxidation resistance.

[0015] As a preferred embodiment, the thickness of the top layer cermet is 0.5–1.0 mm. The thickness of the top layer cermet needs to be controlled within a suitable range; if the thickness is too low, it will result in poor wear resistance, and if the pressing thickness is too high, it will limit the heat transfer performance.

[0016] This invention also provides a method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader, which includes the following steps:

[0017] 1) A TiN coating is deposited on the surface of WC particles to obtain TiN-coated WC particles;

[0018] 2) TiN-coated WC particles are mixed with raw materials including Ti(C,N), Mo2C, TaC, NbC, ZrC, nickel powder, cobalt powder and carbon black to obtain a bottom layer metal-ceramic mixed raw material; the top layer metal-ceramic mixed raw material is prepared according to the preparation process of the bottom layer metal-ceramic mixed raw material.

[0019] 3) Place the bottom layer of metal-ceramic mixture at the bottom of the mold and press it once to form a blank. Then place the top layer of metal-ceramic mixture on top of the blank and press it a second time to form a complete cold-pressed blank.

[0020] 4) Sinter the complete cold-pressed billet to obtain the final product.

[0021] As a preferred embodiment, both the bottom metal-ceramic composite material and the top metal-ceramic composite material contain a molding agent, such as paraffin wax, rubber, PEG, etc.; the molding agent accounts for 3 to 5% of the mass of the bottom metal-ceramic composite material or the top metal-ceramic composite material.

[0022] As a preferred embodiment, the carbon black accounts for 0.3 to 0.6% of the mass of the bottom or top layer of the metal-ceramic mixture.

[0023] As a preferred embodiment, the mixing is ball milling, with a ball milling rate of 50–150 rpm, a ball-to-material ratio of (2–5):1, and a ball milling time of 12–24 h. Under these preferred ball milling conditions, it is possible to ensure that the powder raw materials are fully and uniformly mixed while preventing large WC particles from being broken during the ball milling process.

[0024] As a preferred embodiment, the pressure of the primary compression is 20-30 MPa.

[0025] As a preferred embodiment, the pressure of the secondary pressing is 150–250 MPa. The first pressing needs to be carried out at a low pressure; if the initial pressing pressure is too high, it will cause delamination of the board after the subsequent secondary pressing.

[0026] As a preferred embodiment, the sintering process employs a vacuum-pressure sintering method with a heating rate of 5–10 °C / min. First, the temperature is raised to 1300 °C under vacuum. Once the temperature reaches 1300 °C, argon gas is used to conduct the pressure, with a pressure of 5–100 MPa. The final sintering temperature is 1400–1500 °C, and the holding time is 1–2 hours. Vacuum sintering is performed to remove surface-adsorbed oxygen and other impurities, while pressure sintering is used to inhibit denitrification of titanium carbonitride and promote densification.

[0027] The particle size range of the raw material powders such as Ti(C,N), Mo2C, TaC, NbC, ZrC, nickel powder, cobalt powder and carbon black in this invention is 3 to 7 μm.

[0028] The method for preparing the metal-ceramic material for the aspherical curved glass hot bending heat spreader of the present invention includes the following steps:

[0029] (1) Preparation of WC bulk material: WC powder and carbon black are mixed evenly. The addition of an appropriate amount of carbon black can remove adsorbed oxygen and a certain amount of combined oxygen through carbon-oxygen reaction during high temperature. The content of carbon black is 0.2-0.5% of the mass of WC. The mixing method can be wet ball milling. The ball milling medium is alcohol, the ball-to-material ratio is (3-5):1, the ball milling speed is (200-250) r / min, and the ball milling time is 24-36 h. The mixture is sintered by spark plasma or hot isostatic pressing. The sintering temperature is 1700℃-1800℃. When using spark plasma, the time is 10-30 min, while when using hot isostatic pressing, the time is 1-2 h. After cooling, WC bulk material is obtained.

[0030] (2) Preparation of large TiN-plated WC particles: The WC bulk material obtained in step (1) was crushed and sieved. The size of the sieved WC was 30-60 μm (i.e., 250-400 mesh). Titanium nitride was coated by PVD (vacuum evaporation + nitriding, evaporation at 850-900℃ for 4 hours, vacuum below 1.0×10⁻⁶). -3 After vapor deposition, nitrogen gas is introduced at high temperature and reacted for 1-2 hours. TiN coating is then applied to the surface of WC particles with a coating thickness of 2-5 μm to obtain large TiN-coated WC particles.

[0031] (3) Preparation of the mixture: Weigh the raw material powders, forming agent, and carbon black of the top and bottom metal ceramics according to their mass percentages. The mass of the forming agent and carbon black are 3-5% and 0.3-0.6% of the mass of the raw material powder, respectively. Mix them separately using low-intensity ball milling at a speed of 50-150 rpm and a ball-to-material ratio of (2-5):1 for 12-24 hours. The mixture is then obtained.

[0032] (4) Plate pressing: Plate forming and pressing is carried out by molding. The bottom metal ceramic raw material powder obtained in step (3) is placed in the mold and pressed at a low pressure of 20-30 MPa. After pressing, the upper die punch is lifted and the top metal ceramic raw material powder is placed on the bottom blank in the mold. Then, a high pressure of 150-250 MPa is pressed again. The pressing thickness of the top layer is controlled at 0.8-1.3 mm. During the pressing process, the upper die punch presses down slowly to allow time for the blank to vent, and the pressed cold blank is obtained.

[0033] (5) Sintering of the plate: The cold-pressed blank obtained in step (4) is placed in a sintering furnace. The sintering method is vacuum-pressure sintering. The heating rate is 5-10℃ / min. Vacuum sintering is used before 1300℃ with a vacuum degree of 0.001-1Pa. After 1300℃, argon gas is used to conduct pressure with a pressure of 5-100MPa. The final sintering temperature is 1400-1500℃ and the sintering time is 1-2h. After cooling, the metal ceramic material for hot bending heat-spreading plate of aspherical curved glass is obtained.

[0034] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0035] 1. The metal-ceramic material of the present invention is composed of a double-layer ceramic material. The top layer has good high-temperature dimensional stability and wear resistance, while the bottom layer has excellent thermal conductivity and mechanical strength. It is particularly suitable for use in hot bending heat exchange plates for aspherical curved glass, which can quickly conduct heat while maintaining wear resistance and dimensional stability of the contact surface with the mold.

[0036] 2. The metal-ceramic material of the present invention, by using a high proportion of large-sized WC particles with high thermal conductivity, can further improve the thermal conductivity and high-temperature wear resistance of the metal-ceramic material, and by coating the surface of the large-sized WC particles, it can maintain high stability during sintering and oxidation resistance during use.

[0037] 3. The metal-ceramic material of the present invention is used to prepare heat spreader products. It has excellent overall oxidation resistance, can be used without coating, saving coating components and time, and has good dimensional stability, which can significantly reduce heat spreader replacement time and improve product production efficiency.

[0038] 4. The preparation method of the metal ceramic material of the present invention is simple, the conditions are mild, and the controllability is strong, which is conducive to industrial production. Detailed Implementation

[0039] The following specific embodiments are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims.

[0040] Performance testing: Hardness: GB / T 230.1-2018.

[0041] Bending strength standard GB / T 3851-2015.

[0042] Oxidative weight gain per unit area at 800℃ within 10 hours: in accordance with standard GB / T 13303-1991.

[0043] Thermal conductivity was measured using a laser flash thermal conductivity analyzer.

[0044] Example 1

[0045] The top layer of cermet is composed of 12% nickel and cobalt (nickel to cobalt mass ratio 3:7), 0.8% carbon black, and the remainder is ceramic phase.

[0046] The bottom layer of cermet consists of 25% nickel and cobalt (nickel to cobalt mass ratio 3:7), 0.9% carbon black, and the remainder is ceramic phase.

[0047] The ceramic phase contains the following components by mass percentage: Mo2C 2%, TaC 3%, NbC 1%, ZrC 1.0%, TiN-coated WC particles 25%, and the remainder is Ti(C,N).

[0048] (1) Preparation of WC blocks: WC powder and carbon black were mixed evenly. The carbon black content was 0.2% of the mass of WC. The mixing method was wet ball milling. The ball milling medium was alcohol (anhydrous ethanol). The ball-to-material ratio was 4:1. The ball milling speed was 220 r / min. The ball milling time was 30 h. The mixture was sintered by hot isostatic pressing. The sintering temperature was 1750℃ and the time was 1 h. After cooling, WC blocks were obtained.

[0049] (2) Preparation of large TiN-plated WC particles: The WC bulk material obtained in step (1) was crushed and sieved. The size of the sieved WC was 30-60 μm (i.e., 250-400 mesh). Titanium nitride was coated by PVD (vacuum evaporation + nitriding, evaporation at 850℃ for 4 hours, vacuum below 1.0×10⁻⁶). -3 After the vapor deposition was completed, nitrogen gas was introduced at high temperature and reacted for 1 hour. TiN coating was then applied to the surface of WC particles with a coating thickness of 2 μm to obtain large TiN-coated WC particles.

[0050] (3) Preparation of the mixture: Weigh the raw material powders of the top and bottom layer metal ceramics, paraffin wax, and carbon black according to the mass percentages. The mass of the forming agent and carbon black is 3% and 0.6% of the mass of the raw material powder, respectively. Mix them separately using low-intensity ball milling at a speed of 50 rpm, a ball-to-material ratio of 5:1, and a milling time of 12 h. The mixture is then obtained.

[0051] (4) Plate pressing: Plate forming and pressing is carried out by molding. The bottom metal ceramic raw material powder obtained in step (3) is placed in the mold and pressed at a low pressure of 20MPa. After pressing, the upper die punch is lifted and the top metal ceramic raw material powder is placed on the bottom blank in the mold. Then, a high pressure of 250MPa is performed again. The pressing thickness of the top layer is controlled at 0.8mm. During the pressing process, the upper die punch presses down slowly to allow time for the blank to vent, and the pressed cold blank is obtained.

[0052] (5) Sintering of the plate: The cold-pressed blank obtained in step (4) is placed in a sintering furnace. The sintering method is vacuum-pressure sintering with a heating rate of 5℃ / min. Vacuum sintering is used before 1300℃ with a vacuum degree of 0.8Pa. After 1300℃, argon gas is used to conduct pressure at a pressure of 10MPa. The final sintering temperature is 1500℃ and the sintering time is 1h. After cooling, the metal-ceramic material for hot bending heat spreader of aspherical curved glass is obtained.

[0053] Performance testing: Surface hardness HRA90.5, bottom layer strength 2300MPa, thermal conductivity 35W / m·K, and weight gain per unit area due to oxidation at 800℃ within 10 hours is 9.8×10⁻⁶. -3 mg / mm 2 .

[0054] Example 2

[0055] The top layer of cermet is composed of 10% nickel and cobalt (nickel to cobalt mass ratio of 7:3), 0.4% carbon black, and the remainder is ceramic phase.

[0056] The bottom layer of cermet consists of 27% nickel and cobalt (nickel to cobalt mass ratio of 7:3), 0.5% carbon black, and the remainder is ceramic phase.

[0057] The ceramic phase contains the following components by mass percentage: Mo2C 2%, TaC 1%, NbC 3%, ZrC 1.0%, TiN-coated WC particles 30%, and the remainder is Ti(C,N).

[0058] (1) Preparation of WC blocks: WC powder and carbon black are mixed evenly. The carbon black content is 0.5% of the mass of WC. The mixing method is wet ball milling. The ball milling medium is alcohol (anhydrous ethanol). The ball-to-material ratio is 4:1. The ball milling speed is 220 r / min. The ball milling time is 30 h. The mixture is sintered by hot isostatic pressing. The sintering temperature is 1750℃ and the time is 2 h. After cooling, WC blocks are obtained.

[0059] (2) Preparation of large TiN-plated WC particles: The WC bulk material obtained in step (1) was crushed and sieved. The size of the sieved WC was 30-60 μm (i.e., 250-400 mesh). Titanium nitride was coated by PVD (vacuum evaporation + nitriding, evaporation at 900℃ for 4 hours, vacuum below 1.0×10⁻⁶). -3 After the vapor deposition was completed, nitrogen gas was introduced at high temperature and reacted for 2 hours. TiN coating was then applied to the surface of WC particles with a coating thickness of 5 μm to obtain large TiN-coated WC particles.

[0060] (3) Preparation of the mixture: Weigh the raw material powders of the top and bottom layer metal ceramics, paraffin wax, and carbon black according to the mass percentages. The mass of the forming agent and carbon black are 5% and 0.3% of the mass of the raw material powder, respectively. Mix them separately using low-intensity ball milling at a speed of 150 rpm, a ball-to-material ratio of 2:1, and a milling time of 24 h. The mixture is then obtained.

[0061] (4) Plate pressing: Plate forming and pressing is carried out by molding. The bottom metal ceramic raw material powder obtained in step (3) is placed in the mold and pressed at a low pressure of 30MPa. After pressing, the upper die punch is lifted and the top metal ceramic raw material powder is placed on the bottom blank in the mold. Then, a high pressure of 150MPa is pressed again. The pressing thickness of the top layer is controlled at 1.3mm. During the pressing process, the upper die punch presses down slowly to allow time for the blank to vent, and the pressed cold blank is obtained.

[0062] (5) Sintering of the plate: The cold-pressed blank obtained in step (4) is placed in a sintering furnace. The sintering method is vacuum-pressure sintering with a heating rate of 10℃ / min. Vacuum sintering is used before 1300℃ with a vacuum degree of 0.8Pa. After 1300℃, argon gas is used to conduct pressure at a pressure of 100MPa. The final sintering temperature is 1400℃ and the sintering time is 2h. After cooling, the metal-ceramic material for hot bending heat exchange plate of aspherical curved glass is obtained.

[0063] Performance testing: Surface hardness HRA91.5, bottom layer strength 2460MPa, thermal conductivity 37W / m·K, and oxidation weight gain per unit area of ​​8×10⁻⁶ at 800℃ within 10 hours. -3 mg / mm 2 .

[0064] Example 3

[0065] The top layer of cermet consists of 9% nickel and cobalt (nickel to cobalt mass ratio of 1:1), 0.6% carbon black, and the remainder is ceramic phase.

[0066] The mass percentage composition of the underlying cermet is: 29% nickel and cobalt (nickel to cobalt mass ratio of 1:1), 0.7% carbon black, and the remainder is ceramic phase.

[0067] The ceramic phase contains the following components by mass percentage: Mo2C 3%, TaC 2%, NbC 2%, ZrC 0.7%, TiN-coated WC particles 27%, and the remainder is Ti(C,N).

[0068] (1) Preparation of WC blocks: WC powder and carbon black were mixed evenly. The carbon black content was 0.4% of the mass of WC. The mixing method was wet ball milling. The ball milling medium was alcohol (anhydrous ethanol). The ball-to-material ratio was 4:1. The ball milling speed was 220 r / min. The ball milling time was 30 h. The mixture was sintered by hot isostatic pressing. The sintering temperature was 1750℃ and the time was 1.5 h. After cooling, WC blocks were obtained.

[0069] (2) Preparation of large TiN-plated WC particles: The WC bulk material obtained in step (1) was crushed and sieved. The size of the sieved WC was 30-60 μm (i.e., 250-400 mesh). Titanium nitride was coated by PVD (vacuum evaporation + nitriding, evaporation at 900℃ for 2 hours, vacuum below 1.0×10⁻⁶). -3 After the vapor deposition was completed, nitrogen gas was introduced at high temperature and the reaction was carried out for 2 hours. TiN coating was then applied to the surface of WC particles with a coating thickness of 3 μm to obtain large TiN-coated WC particles.

[0070] (3) Preparation of the mixture: Weigh the raw material powders of the top and bottom layer metal ceramics, paraffin wax, and carbon black according to the mass percentages. The mass of the forming agent and carbon black are 4% and 0.4% of the mass of the raw material powder, respectively. Mix them separately using low-intensity ball milling at 100 rpm, a ball-to-material ratio of 3:1, and a milling time of 18 h. The mixture is then obtained.

[0071] (4) Plate pressing: Plate forming and pressing is carried out by molding. The bottom metal ceramic raw material powder obtained in step (3) is placed in the mold and pressed at a low pressure of 25MPa. After pressing, the upper die punch is lifted and the top metal ceramic raw material powder is placed on the bottom blank in the mold. Then, a high pressure of 200MPa is pressed again. The pressing thickness of the top layer is controlled at 1mm. During the pressing process, the upper die punch presses down slowly to allow time for the blank to vent, and the pressed cold blank is obtained.

[0072] (5) Sintering of the plate: The cold-pressed blank obtained in step (4) is placed in a sintering furnace. The sintering method is vacuum-pressure sintering with a heating rate of 8℃ / min. Vacuum sintering is used before 1300℃ with a vacuum degree of 0.8Pa. After 1300℃, argon gas is used to conduct pressure at a pressure of 60MPa. The final sintering temperature is 1450℃ and the sintering time is 1.5h. After cooling, the metal-ceramic material for hot bending heat spreader of aspherical curved glass is obtained.

[0073] Performance testing: Surface hardness HRA92, bottom layer strength 2780MPa, thermal conductivity 42W / m·K, and oxidation weight gain per unit area of ​​5×10⁻⁶ at 800℃ within 10 hours. -3 mg / mm 2 .

[0074] Example 4

[0075] The top layer of cermet is composed of 8% nickel and cobalt (nickel to cobalt mass ratio of 4:6), 0.6% carbon black, and the remainder is ceramic phase.

[0076] The bottom layer of cermet consists of 32% nickel and cobalt (nickel to cobalt mass ratio of 4:6), 0.6% carbon black, and the remainder is ceramic phase.

[0077] The ceramic phase contains the following components by mass percentage: Mo2C 3.5%, TaC 2%, NbC 2%, ZrC 0.6%, TiN-coated WC particles 28%, and the remainder is Ti(C,N).

[0078] (1) Preparation of WC blocks: WC powder and carbon black were mixed evenly. The carbon black content was 0.3% of the mass of WC. The mixing method was wet ball milling. The ball milling medium was alcohol (anhydrous ethanol). The ball-to-material ratio was 4:1. The ball milling speed was 220 r / min. The ball milling time was 30 h. The mixture was sintered by hot isostatic pressing. The sintering temperature was 1750℃ and the time was 1.5 h. After cooling, WC blocks were obtained.

[0079] (2) Preparation of large TiN-plated WC particles: The WC bulk material obtained in step (1) was crushed and sieved. The size of the sieved WC was 30-60 μm (i.e., 250-400 mesh). Titanium nitride was coated by PVD (vacuum evaporation + nitriding, evaporation at 880℃ for 3 hours, vacuum below 1.0×10⁻⁶). -3 After the vapor deposition was completed, nitrogen gas was introduced at high temperature and the reaction was carried out for 2 hours. TiN coating was then applied to the surface of WC particles with a coating thickness of 4 μm to obtain large TiN-coated WC particles.

[0080] (3) Preparation of the mixture: Weigh the raw material powders of the top and bottom layer metal ceramics, paraffin wax, and carbon black according to the mass percentages. The mass of the forming agent and carbon black are 4% and 0.4% of the mass of the raw material powder, respectively. Mix them separately using low-intensity ball milling at a speed of 100 rpm, a ball-to-material ratio of 4:1, and a milling time of 18 h. The mixture is then obtained.

[0081] (4) Plate pressing: Plate forming and pressing is carried out by molding. The bottom metal ceramic raw material powder obtained in step (3) is placed in the mold and pressed at a low pressure of 25MPa. After pressing, the upper die punch is lifted and the top metal ceramic raw material powder is placed on the bottom blank in the mold. Then, a high pressure of 190MPa is pressed again. The pressing thickness of the top layer is controlled at 1.1mm. During the pressing process, the upper die punch presses down slowly to allow time for the blank to vent, and the pressed cold blank is obtained.

[0082] (5) Sintering of the plate: The cold-pressed blank obtained in step (4) is placed in a sintering furnace. The sintering method is vacuum-pressure sintering with a heating rate of 8℃ / min. Vacuum sintering is used before 1300℃ with a vacuum degree of 0.8Pa. After 1300℃, argon gas is used to conduct pressure with a pressure of 50MPa. The final sintering temperature is 1450℃ and the sintering time is 1.5h. After cooling, the metal ceramic material for hot bending heat spreader of aspherical curved glass is obtained.

[0083] Performance testing: Surface hardness HRA93.5, bottom layer strength 2900MPa, thermal conductivity 45W / m·K, and weight gain per unit area of ​​oxidation at 800℃ within 10 hours is 3×10⁻⁶. -3 mg / mm 2 .

[0084] Comparative Example 1

[0085] The only difference compared to Example 4 is:

[0086] The top layer of cermet is composed of 30% nickel and cobalt (nickel to cobalt mass ratio of 4:6), 0.6% carbon black, and the remainder is ceramic phase.

[0087] The bottom layer of cermet consists of 30% nickel and cobalt (nickel to cobalt mass ratio of 4:6), 0.6% carbon black, and the remainder is ceramic phase.

[0088] Performance testing: Surface hardness HRA83, bottom layer strength 2850MPa, thermal conductivity 44W / m·K, and oxidation weight gain per unit area of ​​8×10⁻⁶ at 800℃ within 10 hours. -1 mg / mm 2 .

[0089] Comparative Example 2

[0090] The only difference compared to Example 4 is that the WC particles are not coated with TiN.

[0091] Performance testing: Surface hardness HRA92.8, bottom layer strength 2800MPa, thermal conductivity 25W / m·K, and weight gain per unit area of ​​oxidation at 800℃ within 10 hours is 4×10⁻⁶. -2 mg / mm2 .

[0092] Comparative Example 3

[0093] The only difference compared to Example 4 is that the WC particle size is 10–20 μm.

[0094] Performance testing: Surface hardness HRA93.3, bottom layer strength 2680MPa, thermal conductivity 28W / m·K, and weight gain per unit area due to oxidation at 800℃ within 10 hours is 3.5×10⁻⁶. -2 mg / mm 2 .

Claims

1. A metal-ceramic material for a non-spherical curved glass hot bending heat spreader, characterized in that: It consists of a top layer and a bottom layer of metal-ceramic, both of which are composed of a metal binder phase and a ceramic phase. The proportion of the metal binder phase in the top layer is lower than that in the bottom layer. The metallic binder phase comprises nickel and cobalt; The metal binder phase in the top-layer cermet has a mass percentage content of 8-15%; The mass percentage content of the metal binder phase in the underlying metal ceramic is 25-35%; The mass percentage composition of cobalt and nickel in the metallic binder phase is (30~70):(30~70); The ceramic phase comprises the following components by mass percentage: Mo2C 2~5%, TaC 1~3%, NbC 1~3%, ZrC 0.5~1.0%, TiN-coated WC particles 25~30%, and the remainder being Ti(C,N); The TiN-coated WC particles have a size of 32~65μm and a TiN coating thickness of 2~5μm.

2. The metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to claim 1, characterized in that: The thickness of the top layer of metal ceramic is 0.5~1.0 mm.

3. The method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to any one of claims 1 to 2, characterized in that: Includes the following steps: 1) A TiN coating is deposited on the surface of WC particles to obtain TiN-coated WC particles; 2) TiN-coated WC particles are combined with Ti(C,N), Mo2C, TaC, NbC, ZrC, nickel powder, and cobalt powder. The raw materials, including carbon black, are mixed to obtain the bottom layer metal-ceramic composite material; the top layer metal-ceramic composite material is prepared according to the preparation process of the bottom layer metal-ceramic composite material. 3) Place the bottom layer of metal-ceramic mixture at the bottom of the mold and press it once to form a blank. Then place the top layer of metal-ceramic mixture on top of the blank and press it a second time to form a complete cold-pressed blank. 4) Sinter the complete cold-pressed billet to obtain the final product.

4. The method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to claim 3, characterized in that: The carbon black accounts for 0.3 to 0.6% of the mass of the underlying metal-ceramic mixture.

5. The method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to claim 3, characterized in that: The mixing is ball milling, with a ball milling rate of 50~150 rpm, a ball-to-material ratio of (2~5):1, and a ball milling time of 12~24 h.

6. The method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to claim 3, characterized in that: The pressure of the first pressing is 20~30MPa; The pressure of the secondary compression is 150~250MPa.

7. The method for preparing a metal-ceramic material for a non-spherical curved glass hot bending heat spreader according to claim 3, characterized in that: The sintering process adopts a vacuum-pressure sintering method with a heating rate of 5~10℃ / min. First, the temperature is raised to 1300℃ in a vacuum environment. When the temperature reaches 1300℃, argon gas is used to conduct pressure at a pressure of 5~100MPa. The final sintering temperature is 1400~1500℃, and the holding time is 1~2h.