High-toughness multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a high-toughness multilayer ceramic substrate and a preparation method thereof. Raw materials of the high-toughness multilayer ceramic substrate comprise the following components in parts by weight: 90-95 parts of aluminum oxide, 13-17 parts of a sintering aid, 2-5 parts of a plasticizer, 1-3 parts of a dispersant, 3-5 parts of a binder, 10-12 parts of an aid and 55-65 parts of water, the auxiliaries comprise boron carbide, copper-tin alloy powder and graphene oxide. According to the technical scheme, the problem of poor toughness of the multi-layer ceramic substrate in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic substrates, and in particular to a high-strength and toughness multilayer ceramic substrate and a preparation method thereof. Background Art

[0002] Multilayer ceramic substrates have become key basic materials in the fields of electronic information, new energy, and aerospace due to their excellent insulation and high temperature resistance. Ceramic substrates such as alumina, silicon nitride, and aluminum nitride have been widely used in power module packaging, sensor carriers, and other scenarios. However, traditional multilayer ceramic materials have exposed the problem of insufficient mechanical properties in practical applications. Researchers added a non-metallic second phase to the raw materials of ceramic substrates, but this did not improve the toughness of the ceramic substrates, which resulted in the ceramic substrates being unable to meet the long-term stable service requirements under complex working conditions.

[0003] In this context, the research and development of high-toughness multilayer ceramic substrates has become an urgent need in the field of ceramic substrates. Summary of the Invention

[0004] The present invention provides a high-strength and toughness multilayer ceramic substrate and a preparation method thereof, which solves the problem of poor toughness of the multilayer ceramic substrate in the related art.

[0005] The technical solutions of the present invention are as follows: The present invention provides a high-strength and tough multilayer ceramic substrate, wherein the raw materials include the following components in parts by weight: 90-95 parts of aluminum oxide, 13-17 parts of a sintering aid, 2-5 parts of a plasticizer, 1-3 parts of a dispersant, 3-5 parts of a binder, 10-12 parts of an additive, and 55-65 parts of water; The auxiliary agents include boron carbide, copper-tin alloy powder and graphene oxide.

[0006] When a sintering aid is added to the high-strength and tough multilayer ceramic substrate of the present invention, the sintering aid can promote ceramic densification, reduce defects such as pores, and improve the density and uniformity of the ceramic, thereby ensuring the mechanical properties of the ceramic substrate.

[0007] As a further technical solution, the mass ratio of the boron carbide, copper-tin alloy powder and graphene oxide is 1:1:0.3~0.4.

[0008] In the high-strength and tough multilayer ceramic substrate of the present invention, when the mass ratio of boron carbide, copper-tin alloy powder and graphene oxide is 1:1:0.3-0.4, the toughness of the ceramic substrate is further improved.

[0009] In the high-strength and tough multilayer ceramic substrate of the present invention, the mass ratio of boron carbide, copper-tin alloy powder and graphene oxide can be 1:1:0.3, 1:1:0.31, 1:1:0.32, 1:1:0.33, 1:1:0.34, 1:1:0.35, 1:1:0.36, 1:1:0.37, 1:1:0.38, 1:1:0.39, 1:1:0.4, and preferably 1:1:0.3.

[0010] As a further technical solution, the graphene oxide is a graphene oxide composite material; The raw materials of the graphene oxide composite material include graphene oxide and 2,4-dihydroxybenzophenone.

[0011] As a further technical solution, the method for preparing the graphene oxide composite material comprises the following steps: The graphene oxide is ground and added to ethanol, ultrasonically dispersed, and mixed evenly. 2,4-dihydroxybenzophenone is added, stirred, concentrated, and dried to obtain the graphene oxide composite material.

[0012] In the high-strength and tough multilayer ceramic substrate of the present invention, the present invention is concerned that graphene oxide is prone to agglomeration during the preparation process of the high-strength and tough multilayer ceramic substrate. Therefore, the present invention uses graphene oxide compounded with 2,4-dihydroxybenzophenone as the graphene oxide composite material. The multiple polar groups in the 2,4-dihydroxybenzophenone molecule make the graphene oxide more compatible with other components in the multilayer ceramic substrate system, thereby improving the dispersion of the graphene oxide. Therefore, the raw material distribution of the multilayer ceramic substrate is more uniform, and the bending strength of the multilayer ceramic substrate is improved.

[0013] As a further technical solution, the mass volume ratio of the graphene oxide and ethanol is 1g:10~15mL.

[0014] As a further technical solution, the power of the ultrasonic dispersion is 100-140 W, and the time is 3-5 hours.

[0015] As a further technical solution, the mass ratio of the graphene oxide to 2,4-dihydroxybenzophenone is 35:2~3.

[0016] In the high-strength and tough multilayer ceramic substrate of the present invention, the mass ratio of graphene oxide to 2,4-dihydroxybenzophenone can be 35:2, 35:2.1, 35:2.2, 35:2.3, 35:2.4, 35:2.5, 35:2.6, 35:2.7, 35:2.8, 35:2.9, or 35:3, preferably 35:3.

[0017] As a further technical solution, the stirring speed is 300-400 rpm, the time is 5-6 hours, and the temperature is 30-40°C.

[0018] As a further technical solution, the sintering aid includes one or more of silicon dioxide, calcium oxide, and magnesium oxide.

[0019] In the high-strength and tough multilayer ceramic substrate of the present invention, the sintering aid can be any one or more of conventional sintering aids, and can be any one or more of titanium dioxide, yttrium oxide, cerium oxide, scandium oxide, lanthanum oxide, silicon dioxide, calcium oxide, and magnesium oxide, preferably one or more of silicon dioxide, calcium oxide, and magnesium oxide.

[0020] As a further technical solution, the plasticizer includes one or both of glycerol and polyethylene glycol.

[0021] As a further technical solution, the dispersant includes one or both of ammonium citrate and sodium polyacrylate.

[0022] In the high-strength and tough multilayer ceramic substrate of the present invention, the dispersant can be any one or more of conventional dispersants, and can be any one or more of sodium hexametaphosphate, sodium tripolyphosphate, ammonium citrate, and sodium polyacrylate, preferably one or two of ammonium citrate and sodium polyacrylate.

[0023] As a further technical solution, the binder includes one or both of polyvinyl alcohol and hydroxypropyl methylcellulose.

[0024] In the high-strength and tough multilayer ceramic substrate of the present invention, the binder may be any one or more conventional binders, and may be any one or more of carboxymethyl cellulose, polyvinyl alcohol, and hydroxypropyl methyl cellulose, preferably one or two of polyvinyl alcohol and hydroxypropyl methyl cellulose.

[0025] The present invention also provides a method for preparing a high-strength and tough multilayer ceramic substrate, which comprises the following steps: S1. Alumina is mixed with an additive, ball-milled, and then uniformly mixed with a sintering aid, a plasticizer, a dispersant, and water, and then a binder is added to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, and performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the high-strength and toughness multilayer ceramic substrate.

[0026] As a further technical solution, in step S1, the ball milling speed is 500-600 rpm, the time is 2-3 hours, and the temperature is 30-50°C.

[0027] The working principle and beneficial effects of the present invention are: In the present invention, boron carbide, copper-tin alloy powder and graphene oxide are added as auxiliary agents to improve the toughness of the multilayer ceramic substrate and also improve the hardness of the ceramic substrate. Boron carbide, copper-tin alloy powder and graphene oxide work together. After the copper-tin alloy powder is added, after the crack passes through the copper-tin alloy powder, the copper-tin alloy powder undergoes plastic deformation, which plays a toughening role. In addition, the addition of boron carbide and copper-tin alloy powder as auxiliary agents in the present invention improves the problem of reduced hardness of the ceramic substrate caused by excessive softness of the copper-tin alloy powder, and improves the hardness of the multilayer ceramic substrate. Boron carbide can hinder the shrinkage of the lateral interface of the matrix, thereby achieving a toughening effect. Graphene oxide, as an auxiliary agent, can inhibit grain boundary migration and refine grains, thereby hindering the movement of dislocations and dissipating fracture energy when fracture occurs. Graphene oxide, copper-tin alloy powder and boron carbide work together in different mechanisms when the ceramic substrate is subjected to external force, thereby improving the toughness of the multilayer ceramic substrate and also improving the hardness of the ceramic substrate. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] In the following examples and comparative examples, the tin content in the copper-tin alloy powder is 9.5 wt %, the balance is copper, the particle size is 500 mesh, the particle size of aluminum oxide is 1 μm, the particle size of silicon dioxide is 1 μm, the particle size of calcium oxide is 1 μm, the particle size of magnesium oxide is 1 μm, the model of polyvinyl alcohol is PVA-205, purchased from Kuraray Co., Ltd., the model of polyethylene glycol is PEG-1000, the model of sodium polyacrylate is NP-800, the particle size of boron carbide is 5000 nm, and the model of graphene oxide is JCGO-99-1-2.

[0030] Example 1 The high-strength and tough multilayer ceramic substrate comprises the following components in parts by weight: 95 parts of aluminum oxide, 5 parts of silicon dioxide, 5 parts of calcium oxide, 7 parts of magnesium oxide, 5 parts of glycerol, 3 parts of ammonium citrate, 5 parts of polyvinyl alcohol, 12 parts of additives, and 65 parts of water. The additives include boron carbide, copper-tin alloy powder and graphene oxide in a mass ratio of 1:1:0.6; A method for preparing a high-strength and tough multilayer ceramic substrate comprises the following steps: S1. Alumina and an additive are mixed, ball-milled at 600 rpm at 50°C for 2 h, and then uniformly mixed with silica, calcium oxide, magnesium oxide, glycerol, ammonium citrate, and water, and then polyvinyl alcohol is added to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, surface printing, laminating 30 layers, conducting the top and bottom, cutting, sintering at 1650°C for 4.5 hours, and cooling to obtain a high-strength and tough multilayer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15μm.

[0031] Example 2 The high-strength and tough multilayer ceramic substrate comprises the following components in parts by weight: 90 parts of aluminum oxide, 5 parts of silicon dioxide, 5 parts of calcium oxide, 3 parts of magnesium oxide, 2 parts of polyethylene glycol, 1 part of sodium polyacrylate, 3 parts of hydroxypropyl methylcellulose, 10 parts of additives, and 55 parts of water. The additives include boron carbide, copper-tin alloy powder and graphene oxide in a mass ratio of 1:1:0.2; A method for preparing a high-strength and tough multilayer ceramic substrate comprises the following steps: S1. Alumina and an additive are mixed, ball-milled at 500 rpm at 30°C for 3 h, and then uniformly mixed with silicon dioxide, calcium oxide, magnesium oxide, polyethylene glycol, sodium polyacrylate, and water, and then hydroxypropyl methylcellulose is added to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, surface printing, laminating 30 layers, conducting the top and bottom, cutting, sintering at 1680°C for 4 hours, and cooling to obtain a high-strength and tough multilayer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15μm.

[0032] Example 3 The only difference between this embodiment and embodiment 2 is that the mass ratio of boron carbide, copper-tin alloy powder and graphene oxide in this embodiment is 1:1:0.5.

[0033] Example 4 The only difference between this embodiment and embodiment 2 is that the mass ratio of boron carbide, copper-tin alloy powder and graphene oxide in this embodiment is 1:1:0.3.

[0034] Example 5 The only difference between this embodiment and embodiment 2 is that the mass ratio of boron carbide, copper-tin alloy powder and graphene oxide in this embodiment is 1:1:0.4.

[0035] Example 6 The only difference between this embodiment and embodiment 4 is that the graphene oxide in this embodiment is replaced by a graphene oxide composite material of equal mass. The method for preparing the graphene oxide composite material comprises the following steps: The graphene oxide was ground and added to ethanol (the mass volume ratio of graphene oxide and ethanol was 1 g:15 mL), ultrasonically dispersed at a power of 140 W for 3 hours, mixed evenly, and 2,4-dihydroxybenzophenone was added (the mass ratio of graphene oxide and 2,4-dihydroxybenzophenone was 35:3). The mixture was stirred at 400 rpm at 40°C for 5 hours, concentrated, and dried to obtain a graphene oxide composite material.

[0036] Example 7 The only difference between this embodiment and embodiment 4 is that the graphene oxide in this embodiment is replaced by a graphene oxide composite material of equal mass. The method for preparing the graphene oxide composite material comprises the following steps: The graphene oxide was ground and added to ethanol (the mass volume ratio of graphene oxide and ethanol was 1 g:10 mL), ultrasonically dispersed at a power of 100 W for 5 hours, mixed evenly, and 2,4-dihydroxybenzophenone was added (the mass ratio of graphene oxide and 2,4-dihydroxybenzophenone was 35:2). The mixture was stirred at 300 rpm at 30°C for 6 hours, concentrated, and dried to obtain a graphene oxide composite material.

[0037] Comparative Example 1 The only difference between this comparative example and Example 2 is that the auxiliary agent in this comparative example includes copper-tin alloy powder and graphene oxide in a mass ratio of 1:0.2.

[0038] Comparative Example 2 The only difference between this comparative example and Example 2 is that the auxiliary agent in this comparative example includes boron carbide and graphene oxide in a mass ratio of 1:0.2.

[0039] Comparative Example 3 The only difference between this comparative example and Example 2 is that the auxiliary agent in this comparative example includes boron carbide and copper-tin alloy powder in a mass ratio of 1:1.

[0040] Comparative Example 4 The only difference between this comparative example and Example 2 is that this comparative example does not contain an auxiliary agent.

[0041] Experimental Example 1 The high-strength and toughness multilayer ceramic substrates produced in Examples 1-5 and Comparative Examples 1-4 were tested for fracture toughness according to the method specified in GB / T 23806-2009, "Fine Ceramics - Test Method for Fracture Toughness - Single Edge Precracked Beam (SEPB) Method," and for Vickers hardness according to the method specified in GB / T 16534-2009, "Fine Ceramics - Test Method for Room-Temperature Hardness." The test results are shown in Table 1.

[0042] Table 1 Fracture toughness and Vickers hardness test results

[0043] As shown in Table 1, the fracture toughness of the high-strength and tough multilayer ceramic substrate prepared by the present invention reaches 9.3 MPa·m 1 / 2 As above, the Vickers hardness of 20.2 GPa is reached. Therefore, the present invention uses boron carbide, copper-tin alloy powder and graphene oxide as additives to improve the fracture toughness of the multilayer ceramic substrate and also improve the hardness of the multilayer ceramic substrate.

[0044] Experimental Example 2 The flexural strength of the samples of Examples 4 and 6-7 was tested according to the test method specified in GB / T 6569-2006 "Test Method for Flexural Strength of Fine Ceramics", using a three-point bending test. The test results are shown in Table 2.

[0045] Table 2 Bending strength test results

[0046] As shown in Table 2, the flexural strength of the high-strength and tough multilayer ceramic substrates prepared in Examples 6 and 7 of the present invention reached above 477 MPa. Therefore, the present invention uses graphene oxide compounded with 2,4-dihydroxybenzophenone as the graphene oxide composite material to improve the flexural strength of the high-strength and tough multilayer ceramic substrate.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. High-strength and tough multilayer ceramic substrate, characterized in that: The raw materials include the following components in parts by weight: 90-95 parts of alumina, 13-17 parts of sintering aid, 2-5 parts of plasticizer, 1-3 parts of dispersant, 3-5 parts of binder, 10-12 parts of auxiliary agent, and 55-65 parts of water; The auxiliary agents include boron carbide, copper-tin alloy powder and graphene oxide.

2. The high-strength and tough multilayer ceramic substrate according to claim 1, characterized in that: The mass ratio of the boron carbide, copper-tin alloy powder and graphene oxide is 1:1:0.3-0.

4.

3. The high-strength and tough multilayer ceramic substrate according to claim 1, characterized in that: The graphene oxide is a graphene oxide composite material; The raw materials of the graphene oxide composite material include graphene oxide and 2,4-dihydroxybenzophenone.

4. The high-strength and tough multilayer ceramic substrate according to claim 3, characterized in that: The method for preparing the graphene oxide composite material comprises the following steps: The graphene oxide is ground and added to ethanol, ultrasonically dispersed, and mixed evenly. 2,4-dihydroxybenzophenone is added, stirred, concentrated, and dried to obtain the graphene oxide composite material.

5. The high-strength and tough multilayer ceramic substrate according to claim 4, characterized in that: The power of the ultrasonic dispersion is 100-140W, and the time is 3-5 hours.

6. The high-strength and tough multilayer ceramic substrate according to claim 4, characterized in that: The mass ratio of the graphene oxide to 2,4-dihydroxybenzophenone is 35:2-3.

7. The high-strength and tough multilayer ceramic substrate according to claim 4, characterized in that: The stirring speed is 300-400 rpm, the time is 5-6 hours, and the temperature is 30-40°C.

8. The high-strength and tough multilayer ceramic substrate according to claim 1, characterized in that: The sintering aid includes one or more of silicon dioxide, calcium oxide, and magnesium oxide; The plasticizer includes one or both of glycerol and polyethylene glycol.

9. The high-strength and tough multilayer ceramic substrate according to claim 1, characterized in that: The dispersant includes one or both of ammonium citrate and sodium polyacrylate; The binder includes one or both of polyvinyl alcohol and hydroxypropyl methylcellulose.

10. A method for preparing a high-strength and tough multilayer ceramic substrate, for preparing the high-strength and tough multilayer ceramic substrate according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Alumina is mixed with an additive, ball-milled, and then uniformly mixed with a sintering aid, a plasticizer, a dispersant, and water, and then a binder is added to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the high-strength and toughness multilayer ceramic substrate.

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