Corrosion-resistant high-performance ceramic substrate and preparation method thereof

Abstract

The invention discloses a corrosion-resistant high-performance ceramic substrate and a preparation method thereof, and belongs to the technical field of ceramic substrates. According to the invention, a carboxyl-containing copolymer is modified as a dispersing agent, and carboxylic acid groups in the carboxyl-containing copolymer and the surface of powder form chemical bonding or electrostatic adsorption, so that repulsive force among particles is enhanced, agglomeration is reduced, and the viscosity and thixotropy of the slurry are remarkably improved; and by adopting an organic tape casting process and optimizing the ball milling times and time and the raw material ratio, the uniformity and stability of the ceramic substrate material are ensured, so that the comprehensive performance of the ceramic substrate is effectively improved, and the problems of low bending strength and poor corrosion resistance of the silicon nitride ceramic substrate are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic substrates, and more specifically, relates to a corrosion-resistant high-performance ceramic substrate and a preparation method thereof. Background Art

[0002] Substrate materials generally include three categories: epoxy resin substrates, metal material substrates, and ceramic substrates. Among them, ceramic substrates have extremely high flexural strength and fracture toughness in terms of mechanical properties, and extremely high thermal conductivity, low coefficient of thermal expansion, low dielectric constant, and high anti-electric penetration ability in terms of physical properties, and have good soldering process performance. As the core material in the fields of electronic packaging, high-temperature sensors, chemical reactors, etc., the corrosion resistance of ceramic substrates directly affects the reliability and lifespan of devices in extreme environments. With the development of technology, higher requirements are put forward for the stability of substrate materials in corrosive media such as strong acids / alkalis, high-temperature molten salts, and oxidizing atmospheres.

[0003] Ceramic substrates mainly include four materials: beryllium oxide, alumina, aluminum nitride, and silicon nitride. However, alumina ceramic sheets have disadvantages such as low thermal conductivity (<30 W / (m·K)) and a mismatch in the coefficient of thermal expansion with Si. Although beryllium oxide ceramics have relatively excellent comprehensive properties, their production cost is high and they are toxic. Although aluminum nitride ceramics have relatively excellent comprehensive properties, their production cost is high and their applications are also limited.

[0004] Silicon nitride is a strong covalent bond compound with a relative molecular mass of 140.68. The common crystal forms are α-Si3N4 and β-Si3N4, both belonging to the hexagonal crystal system. Compared with β-Si3N4, α-Si3N4 has a lower structural symmetry and a larger internal strain energy, belongs to a high-temperature (>1400 °C) metastable phase, and has a better hardness than β-Si3N4.

[0005] Although using silicon nitride as a substrate material has obvious performance advantages, there are problems such as low sintering density, low raw material utilization rate, and the need to improve corrosion resistance in the actual production process, which restricts the large-scale use of such materials. It is urgent to make further improvements in raw material preparation and production processes. Summary of the Invention

[0006] Aiming at the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a preparation method for a corrosion-resistant high-performance ceramic substrate. By adopting the organic tape casting process and optimizing the ball milling times and time, and the raw material ratio, the uniformity and stability of the ceramic substrate material are ensured. The present invention also provides a corrosion-resistant high-performance ceramic substrate prepared by the above preparation method, which has excellent high-temperature resistance.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A preparation method of a corrosion-resistant high-performance ceramic substrate, comprising the following steps:

[0009] (1) Mix α-Si3N4 powder, magnesium oxide, yttrium oxide, magnesium silicon nitride, carboxyl-containing copolymer modification, absolute ethanol and toluene, and place them in a ball mill for ball milling to obtain slurry A;

[0010] (2) Mix acrylic resin, polyethylene glycol adipate, absolute ethanol and toluene, and place them in another ball mill for ball milling to obtain slurry B;

[0011] (3) Pour slurry B in step (2) into the ball mill in step (1) for mixing. After ball milling, a casting slurry is obtained. After filtration, it is poured into a degassing tank for vacuum degassing, and then introduced into a casting machine for casting;

[0012] (4) Cut, stack and press the cast green body. Place the pressed green body in a vacuum debinding furnace and carry out debinding in a nitrogen atmosphere to remove the organic components in the green body. Place the debound green body in a gas pressure sintering furnace for sintering, and cool it to room temperature with the furnace to obtain the ceramic substrate.

[0013] Preferably, in step (1), the mass ratio of α-Si3N4 powder, magnesium oxide, yttrium oxide and magnesium silicon nitride is 25-35: 0.3-0.5: 0.2-0.3: 0.3-0.5.

[0014] Preferably, in step (1), the mass ratio of α-Si3N4 powder, magnesium oxide, yttrium oxide and magnesium silicon nitride is 30: 0.3-0.5: 0.2: 0.3-0.5.

[0015] Preferably, in step (2), the mass ratio of acrylic resin and polyethylene glycol adipate is 0.5-1.5: 1.

[0016] Preferably, in step (2), the mass ratio of acrylic resin and polyethylene glycol adipate is 0.8-1: 1.

[0017] Preferably, in step (1), the mass ratio of absolute ethanol and toluene is 4: 1, and the ball milling time is 12-24 h.

[0018] Preferably, in step (2), the mass ratio of absolute ethanol and toluene is 2: 1, and the ball milling time is 24-36 h.

[0019] Preferably, in step (3), the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm.

[0020] Preferably, in the step (3), the working pressure of the isostatic press is 30 Mpa, the temperature is 70 °C, and the pressing time is 1 h.

[0021] In the step (3), the sintering temperature is 1850 - 1900 °C, the nitrogen pressure is 3 MPa, and the sintering time is 4 h.

[0022] The ceramic substrate is prepared by the preparation method of the corrosion-resistant high-performance ceramic substrate.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1) The present invention selects a carboxyl-containing copolymer modification as a dispersant. Through the formation of chemical bonding or electrostatic adsorption between the carboxylic acid groups in the carboxyl-containing copolymer and the powder surface, the repulsive force between particles is enhanced, agglomeration is reduced, and the viscosity and thixotropy of the slurry are significantly improved.

[0025] 2) The present invention adopts an organic tape casting process and optimizes the ball milling times and time, and the raw material ratio, ensuring the uniformity and stability of the ceramic substrate material, thereby effectively improving the comprehensive performance of the corrosion-resistant ceramic substrate.

[0026] 3) The preparation method of the present invention has the advantages of simple process, easy control of parameters, and easy realization of industrial production, and the prepared ceramic substrate has excellent performance. Specific Embodiments

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described below with reference to specific embodiments. In the following embodiments, unless otherwise specified, the technical means used are all conventional means well-known to those skilled in the art. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0028] Among the raw materials used in the following embodiments, the α-Si3N4 powder is purchased from Denka of Japan, and the product model is CN-9FWS (the α-phase content is greater than 91%, the average particle size D50 is 0.7 μm, and the specific surface area is 11 m 2 / g). The β-Si3N4 powder was purchased from Zhejiang Asia-America Nano Technology Co., Ltd., with a purity of 99.9%. The acrylic resin and the carboxyl group-containing copolymer modification were both purchased from Japan's Kyoei Co., Ltd. The product model of the acrylic resin is KC-1300, and the product model of the carboxyl group-containing copolymer modification is G-700. The polyethylene glycol propylene glycol ester was purchased from Wanshengda Chemical Industry Co., Ltd., with the product model of W-2500 and a viscosity of 3000-4000 mpa·s. The yttrium oxide and magnesium oxide were purchased from Xiamen Golden Tungsten New Materials Co., Ltd. The product model of magnesium oxide is GFS-2 (average particle size D50 is 0.98 μm, specific surface area is 70.4 m 2 / g, purity greater than 99.95%), and the product model of yttrium oxide is FXY-2 (average particle size D50 is 0.7-1.1 μm, specific surface area is 15-25 m 2 / g, purity greater than 99.999%). The magnesium silicon nitride was purchased from Qilu Institute of Opto-Physics and Engineering Technology, with the model of ZKM-01, a purity of 99.99%, and an average particle size D50 of 0.6-5 μm.

[0029] Example 1

[0030] A preparation method of a corrosion-resistant high-performance ceramic substrate, comprising the following steps:

[0031] (1) Mix 30 kg of α-Si3N4 powder, 0.3 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.5 kg of magnesium silicon nitride, 2 kg of carboxyl group-containing copolymer modification, 20 kg of absolute ethanol and 5 kg of toluene, and then add them to a roller ball mill tank for ball milling for 24 h;

[0032] (2) Mix 15 kg of acrylic resin, 12 kg of polyethylene glycol propylene glycol ester, 10 kg of absolute ethanol and 5 kg of toluene, and then add them to another ball mill tank for ball milling for 24 h;

[0033] (3) Pour the slurry after the ball milling in step (2) into the roller ball mill tank in step (1) for mixing. After ball milling for 48 h, a casting slurry is obtained. After filtration, it is poured into a degassing tank, and the air bubbles in the casting slurry are removed under a vacuum degree of -1 MPa. Then it is introduced into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0034] (4) Cut the cast green body into a suitable size. After stacking every two green bodies by rotating 90°, press them under an isostatic press at a working pressure of 30 Mpa and 70 °C for 1 h to obtain a pressed green body;

[0035] (5) Place the pressed green body into a vacuum debinding furnace and perform debinding in a nitrogen atmosphere to remove the organic components in the green body. Then place the debound green body into a gas pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and cool it to room temperature with the furnace to obtain a ceramic substrate.

[0036] Example 2

[0037] A method for preparing a corrosion-resistant high-performance ceramic substrate, comprising the following steps:

[0038] (1) Mix 30 kg of α-Si3N4 powder, 0.3 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.5 kg of magnesium silicon nitride, 2 kg of carboxyl-containing copolymer modification, 20 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to a roller ball mill tank and ball mill for 24 h;

[0039] (2) Mix 12 kg of acrylic resin, 15 kg of polyethylene glycol adipate, 10 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to another ball mill tank and ball mill for 24 h;

[0040] (3) Pour the slurry after the ball milling in step (2) into the roller ball mill tank in step (1) and mix. After ball milling for 48 h, a casting slurry is obtained. After filtration, pour it into a degassing tank and remove the bubbles in the casting slurry under a vacuum degree of -1 Mpa. Then introduce it into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0041] (4) Cut the cast green body into a suitable size. After stacking every two green bodies with a 90° rotation, press them under an isostatic press at a working pressure of 30 Mpa and 70 °C for 1 h to obtain a pressed green body;

[0042] (5) Place the pressed green body into a vacuum debinding furnace and perform debinding in a nitrogen atmosphere to remove the organic components in the green body. Then place the debound green body into a gas pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and cool it to room temperature with the furnace to obtain a ceramic substrate.

[0043] Example 3

[0044] A method for preparing a corrosion-resistant high-performance ceramic substrate, comprising the following steps:

[0045] (1) Mix 30 kg of α-Si3N4 powder, 0.5 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.3 kg of magnesium silicon nitride, 2 kg of carboxyl-containing copolymer modification, 20 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to a roller ball mill tank and ball mill for 24 h;

[0046] (2) Mix 12 kg of acrylic resin, 15 kg of poly(propylene glycol) adipate, 10 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to another ball mill tank for ball milling for 24 h;

[0047] (3) Pour the slurry after the ball milling in step (2) into the roller ball mill tank in step (1) for mixing. After ball milling for 48 h, a casting slurry is obtained. After filtration, pour it into a degassing tank, remove the bubbles in the casting slurry under a vacuum degree of -1 MPa, and introduce it into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0048] (4) Cut the cast green body into appropriate sizes. After stacking every two green bodies by rotating 90°, press them under an isostatic press at a working pressure of 30 Mpa and 70 °C for 1 h to obtain a pressed green body;

[0049] (5) Put the pressed green body into a vacuum debinding furnace and perform debinding under a nitrogen atmosphere to remove the organic components in the green body. Put the debound green body into a gas pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and then cool it to room temperature with the furnace to obtain a ceramic substrate.

[0050] Comparative Example 1

[0051] A preparation method of a corrosion-resistant high-performance ceramic substrate, comprising the following steps:

[0052] (1) Mix 30 kg of α-Si3N4 powder, 0.3 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.5 kg of magnesium silicon nitride, 2 kg of carboxyl-containing copolymer modification, 20 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to a roller ball mill tank for ball milling for 3 h;

[0053] (2) Mix 15 kg of acrylic resin, 12 kg of poly(propylene glycol) adipate, 10 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to another ball mill tank for ball milling for 24 h;

[0054] (3) Pour the slurry after the ball milling in step (2) into the roller ball mill tank in step (1) for mixing. After ball milling for 48 h, a casting slurry is obtained. After filtration, pour it into a degassing tank, remove the bubbles in the casting slurry under a vacuum degree of -1 MPa, and introduce it into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0055] (4) Cut the cast green body into appropriate sizes. After stacking every two green bodies by rotating 90°, press them under an isostatic press at a working pressure of 30 Mpa and 70 °C for 1 h to obtain a pressed green body;

[0056] (5) Place the pressed green body into a vacuum debinding furnace and perform debinding in a nitrogen atmosphere to remove the organic components in the green body. Then, place the debound green body into a gas-pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and cool it to room temperature with the furnace to obtain a ceramic substrate.

[0057] Comparative Example 2

[0058] A preparation method of a corrosion-resistant and high-performance ceramic substrate includes the following steps:

[0059] (1) Mix 30 kg of α-Si3N4 powder, 0.3 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.5 kg of magnesium silicon nitride, 2 kg of carboxyl-containing copolymer modification, 15 kg of acrylic resin, 12 kg of polyethylene glycol adipate, 30 kg of absolute ethanol, and 10 kg of toluene, and then add the mixture to a roller ball mill tank for ball milling for 24 h to obtain a casting slurry. After filtration, pour it into a degassing tank and remove the bubbles in the casting slurry under a vacuum degree of -1 Mpa, and then introduce it into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0060] (2) Cut the cast green body into a suitable size. After stacking every two green bodies by rotating 90°, press them under an isostatic press at a working pressure of 30 Mpa and 70 °C for 1 h to obtain a pressed green body;

[0061] (3) Place the pressed green body into a vacuum debinding furnace and perform debinding in a nitrogen atmosphere to remove the organic components in the green body. Then, place the debound green body into a gas-pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and cool it to room temperature with the furnace to obtain a ceramic substrate.

[0062] Comparative Example 3

[0063] A preparation method of a corrosion-resistant and high-performance ceramic substrate includes the following steps:

[0064] (1) Mix 28 kg of α-Si3N4 powder, 2 kg of β-Si3N4 powder, 0.3 kg of magnesium oxide, 0.2 kg of yttrium oxide, 0.5 kg of magnesium silicon nitride, 2 kg of carboxyl-containing copolymer modification, 20 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to a roller ball mill tank for ball milling for 24 h;

[0065] (2) Mix 15 kg of acrylic resin, 12 kg of polyethylene glycol adipate, 10 kg of absolute ethanol, and 5 kg of toluene, and then add the mixture to another ball mill tank for ball milling for 24 h;

[0066] (3) Pour the slurry after ball milling in step (2) into the drum ball mill tank in step (1) for mixing. After ball milling for 48 h, a casting slurry is obtained. After filtration, it is poured into a degassing tank, and the air bubbles in the casting slurry are removed under a vacuum of -1 MPa. Then it is introduced into a casting machine for casting. The casting width is 550 mm, the casting speed is 0.2 m / min, and the height of the casting machine blade is 0.5 mm;

[0067] (4) Cut the cast green body into appropriate sizes. After stacking every two green bodies by rotating 90°, press them under an isostatic press with a working pressure of 30 Mpa and a temperature of 70 °C for 1 h to obtain the pressed green body;

[0068] (5) Put the pressed green body into a vacuum debinding furnace and perform debinding under a nitrogen atmosphere to remove the organic components in the green body. Then put the debound green body into a gas pressure sintering furnace and sinter it at 1880 °C under a nitrogen pressure of 3 Mpa for 4 h, and cool it to room temperature with the furnace to obtain a ceramic substrate.

[0069] Perform performance characterization tests on the ceramic substrates prepared in Examples 1-3 and Comparative Examples 1-3. The results are shown in Table 1. Among them, the hardness test is carried out by the Vickers indentation method, the pressing load is 5 kg, and the Vickers hardness of the measurement point is obtained after maintaining the pressure for 10 s. The fracture toughness test is carried out by the three-point bending method. The sample specifications are 3 mm × 4 mm × 36 mm. After grinding and polishing, the bending strength of the sample is tested by equipment. The span is 30 mm, and the indenter loading rate is 0.5 mm / min. The thermal conductivity test is carried out by the transient plane heat source method.

[0070] Table 1 Performance test results of ceramic substrates prepared in Examples 1-3 and Comparative Examples 1-3

[0071]

[0072] As can be seen from Table 1, the ceramic substrates prepared by the present invention have good mechanical properties and thermal conductivity.

[0073] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a corrosion-resistant high-performance ceramic substrate, characterized in that, It consists of the following steps: (1) Mix α-Si3N4 powder, magnesium oxide, yttrium oxide, magnesium silicon nitride, carboxyl group-containing copolymer modification, absolute ethanol and toluene, and then place them in a ball mill tank for ball milling to obtain slurry A; (2) Mix acrylic resin, polyethylene glycol adipate, absolute ethanol and toluene, and then place them in another ball mill tank for ball milling to obtain slurry B; (3) Pour the slurry B in step (2) into the ball mill tank in step (1) for mixing. After ball milling, a casting slurry is obtained. After filtration, it is poured into a degassing tank for vacuum degassing, and then introduced into a casting machine for casting; (4) The cast green body is subjected to cutting, stacking and pressing treatments. The pressed green body is placed in a vacuum debinding furnace and debound in a nitrogen atmosphere to remove the organic components in the green body. The debound green body is placed in a gas pressure sintering furnace for sintering, and cooled to room temperature with the furnace to obtain a ceramic substrate.

2. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, wherein, In the step (1), the mass ratio of α-Si3N4 powder, magnesium oxide, yttrium oxide and magnesium silicon nitride is 25-35: 0.3-0.5: 0.2-0.3: 0.3-0.

5.

3. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 2, characterized in that, In the step (1), the mass ratio of α-Si3N4 powder, magnesium oxide, yttrium oxide and magnesium silicon nitride is 30: 0.3-0.5: 0.2: 0.3-0.

5.

4. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, wherein, In the step (2), the mass ratio of acrylic resin and polyethylene glycol adipate is 0.5-1.5:

1.

5. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 4, characterized in that, In the step (2), the mass ratio of acrylic resin and polyethylene glycol adipate is 0.8-1:

1.

6. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, characterized in that In the step (1), the mass ratio of absolute ethanol and toluene is 4: 1, and the ball milling time is 12-24 h.

7. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, characterized in that, In the step (3), the casting speed is 0.2 m / min, and the height of the doctor blade of the casting machine is 0.5 mm.

8. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, characterized in that, In the step (3), the working pressure of the isostatic press is 30 Mpa, the temperature is 70 °C, and the pressing time is 1 h.

9. The preparation method of the corrosion-resistant high-performance ceramic substrate according to claim 1, wherein In the step (3), the sintering temperature is 1850-1900 °C, the nitrogen pressure is 3 MPa, and the sintering time is 4 h.

10. A ceramic substrate is prepared by the method for preparing a corrosion-resistant high-performance ceramic substrate according to any one of claims 1-9.

Images