High-strength wear-resistant multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a high-strength wear-resistant multilayer ceramic substrate and a preparation method thereof. The high-strength wear-resistant multilayer ceramic substrate comprises the following raw materials in parts by weight: 70-80 parts of aluminum oxide, 2-3 parts of a dispersant, 3-5 parts of a plasticizer, 8-12 parts of a binder, 8-10 parts of a sintering aid and 80-90 parts of water, the aluminum oxide is modified aluminum oxide, the modified aluminum oxide is obtained by modifying aluminum oxide with a modifier, and the modifier comprises diphenyl silanediol and a biphenyl compound. According to the technical scheme, the problems of insufficient strength and wear resistance of the multilayer ceramic substrate in the prior art are solved.

Description

Technical Field

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

[0002] Alumina ceramic substrates are widely used in integrated circuits, power devices and other fields due to their low cost and stable dielectric properties. However, their insufficient wear resistance and strength significantly restrict the high-end application of ceramic substrates. One of the reasons for this problem is the agglomeration of alumina powder.

[0003] The main reason for alumina powder agglomeration is the hydroxyl groups formed on the powder surface. On the one hand, the hydroxyl groups on the powder surface can connect different particles through hydrogen bonds. Especially in a humid environment, the hydrogen bonding force significantly enhances the tendency of agglomeration. On the other hand, the hydroxyl groups on the surface of alumina particles easily undergo condensation reactions with the hydroxyl groups on the surfaces of other particles, forming hard agglomerates connected by chemical bonds, which are difficult to break through physical dispersion methods. The presence of agglomerates not only forms stress concentration points, which are prone to cracking under the action of external forces, resulting in a decrease in strength, but also increases the surface roughness of the ceramic substrate. During friction, the raised parts are prone to fall off due to stress concentration. The inconsistent hardness caused by the agglomerates will form preferential wear areas, reducing the wear resistance of the multilayer ceramic substrate.

[0004] Therefore, it is necessary to propose a high-strength and wear-resistant multilayer ceramic substrate and a preparation method thereof to solve the problem of insufficient strength and wear resistance caused by agglomeration of alumina powder. Summary of the Invention

[0005] The present invention provides a high-strength and wear-resistant multilayer ceramic substrate and a preparation method thereof, which solves the problem of insufficient strength and wear resistance of the multilayer ceramic substrate in the related art.

[0006] The technical solution of the present invention is as follows: The present invention proposes a high-strength, wear-resistant multi-layer ceramic substrate, comprising the following component raw materials in parts by weight: 70-80 parts of aluminum oxide, 2-3 parts of dispersant, 3-5 parts of plasticizer, 8-12 parts of binder, 8-10 parts of sintering aid, and 80-90 parts of water. The aluminum oxide is modified aluminum oxide, which is obtained by modifying aluminum oxide with a modifier, and the modifier includes diphenylsilanediol and a biphenyl compound.

[0007] As a further technical solution, in the raw materials of the modified alumina, the mass ratio of the modifier to the alumina is 4~5:50; for example, it can be 4:50, 4.1:50, 4.2:50, 4.3:50, 4.4:50, 4.5:50, 4.6:50, 4.7:50, 4.8:50, 4.9:50, 1:10, and preferably 1:10.

[0008] As a further technical solution, the mass ratio of the diphenylsilanediol to the biphenyl compound is 1-2:1.

[0009] The raw materials of the high-strength wear-resistant multilayer ceramic substrate of the present invention include a modifier for modifying alumina composed of diphenylsilanediol and a biphenyl compound in a mass ratio of 1 to 2:1. The diphenylsilanediol can combine with hydroxyl groups on the surface of the alumina, occupy the hydroxyl sites on the surface of the alumina, block the further condensation of the hydroxyl groups, and introduce benzene rings with a steric hindrance effect. If the amount of diphenylsilanediol used is too small, the hydroxyl coverage rate on the surface of the alumina is insufficient, and excessive unoccupied hydroxyl groups will still condense and cause agglomeration. The biphenyl compound has a planar rigid structure. If its content is too high, the rigidity and toughness will be unbalanced, which is not conducive to the bending strength and wear resistance of the multilayer ceramic substrate. When the mass ratio of diphenylsilanediol to the biphenyl compound is 1 to 2:1, the diphenylsilanediol can effectively occupy the hydroxyl groups on the surface of the alumina and introduce an appropriate amount of benzene rings. The addition amount of the biphenyl compound is also moderate, which can achieve a balance between strength and toughness and improve the strength and wear resistance of the multilayer ceramic substrate.

[0010] As a further technical solution, the biphenyl compound includes one or more of m-terphenyl, 4-methylbiphenyl, and 4-tert-butylbiphenyl, preferably 4-tert-butylbiphenyl.

[0011] Among the raw materials of the high-strength and wear-resistant multi-layer ceramic substrate of the present invention, the biphenyl compound in the alumina modifier is preferably 4-tert-butylbiphenyl. The reason is that: m-terphenyl forms a planar conjugation with three benzene rings, has the strongest rigidity, and is prone to cause an imbalance between strength and toughness. However, due to its planar structure, it can effectively inhibit vertical agglomeration, but does not have a good steric hindrance effect in the horizontal direction. In addition to the biphenyl structure, 4-methylbiphenyl also contains a methyl group. The methyl group is small in size, and the rigidity mainly comes from the biphenyl. Therefore, it has no advantage in terms of rigidity and steric hindrance. The preferred 4-tert-butylbiphenyl, in addition to the biphenyl structure, also contains a tert-butyl group. The rigidity of the tert-butyl group is weaker than that of the benzene ring, and the tert-butyl group is larger in size. The presence of the tert-butyl group will occupy a larger space. Therefore, when the biphenyl compound is preferably 4-tert-butylbiphenyl, the performance degradation caused by excessive rigidity can be further avoided, and the strength and wear resistance of the multi-layer ceramic substrate can be further improved.

[0012] As a further technical solution, the preparation method of the modified alumina includes the following steps: dispersing diphenylsilanediol in toluene, adding alumina, performing a first mixing and then drying to obtain pretreated alumina, dispersing a biphenyl compound in toluene, adding the pretreated alumina, performing a second mixing and then drying to obtain modified alumina.

[0013] Among the raw materials of the high-strength and wear-resistant multilayer ceramic substrate of the present invention, in the preparation process of modified alumina, diphenylsilanediol is first used to pre-modify the alumina, occupying the hydroxyl groups on the surface of the alumina and introducing benzene rings to initially achieve the dispersion of the alumina, and then a biphenyl compound is used for modification. The benzene rings interact with each other through π-π stacking, further improving the dispersibility of the alumina powder. At the same time, the introduced biphenyl structure has a certain rigidity, which can further improve the strength and wear resistance of the multilayer ceramic substrate.

[0014] As a further technical solution, in the preparation method of modified alumina, the mass ratio of the toluene to the alumina is 3 to 5:1, for example, it can be 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, preferably 4:1.

[0015] As a further technical solution, the first mixing time is 2 to 4 hours, for example, 2 hours, 2.3 hours, 2.5 hours, 2.8 hours, 3 hours, 3.5 hours, 3.8 hours, 4 hours, preferably 3 hours.

[0016] As a further technical solution, the second mixing time is 3 to 4 hours, for example, it can be 3 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, 4 hours, preferably 3.5 hours.

[0017] As a further technical solution, the dispersant includes one or both of sodium polyacrylate and polyacrylic acid, preferably sodium polyacrylate.

[0018] A dispersant is added to the raw materials of the high-strength, wear-resistant multi-layer ceramic substrate of the present invention. The dispersant can also prevent powder agglomeration. The particles uniformly dispersed during the raw material mixing stage can avoid sedimentation and stratification, ensuring that the raw material composition of each layer of the substrate is consistent, and reducing defects such as cracks and pores caused by uneven composition during the subsequent sintering process. The uniformly dispersed particles are in closer contact during sintering, which helps to improve the surface quality of the multi-layer ceramic substrate.

[0019] As a further technical solution, the plasticizer includes one or both of dibutyl phthalate and dioctyl phthalate, preferably dibutyl phthalate.

[0020] The raw materials of the high-strength, wear-resistant multi-layer ceramic substrate of the present invention are added with a plasticizer. The addition of the plasticizer can improve the fluidity of the material during the mixing process, thereby making it easier to operate molding processes such as casting. The plasticizer also has a lubricating and bridging effect on the powder particles, which is beneficial to the dispersion and stability of the slurry. It can prevent the ceramic powder particles from settling in the slurry, so that the slurry maintains uniformity during storage and use, ensuring consistent performance of various parts of the substrate.

[0021] As a further technical solution, the binder is polyvinyl alcohol.

[0022] The high-strength wear-resistant multilayer ceramic substrate of the present invention is prepared by adding a binder to the raw materials. The addition of the binder can enhance the bonding strength between the raw material components, avoid cracks caused by loose powder, and improve the processing performance of the multilayer ceramic substrate.

[0023] As a further technical solution, the sintering aid includes one or more of magnesium oxide, calcium oxide, and titanium dioxide, preferably magnesium oxide.

[0024] A sintering aid is added to the raw materials of the high-strength, wear-resistant multilayer ceramic substrate of the present invention. The sintering aid can form a low-melting-point liquid phase at high temperature, which can fill the pores of the material, promote the densification of the ceramic substrate, and inhibit the abnormal growth of grains to form a fine-grained strengthened structure, further improving the structural uniformity of the multilayer ceramic substrate.

[0025] The present invention also provides a method for preparing a high-strength, wear-resistant, multi-layer ceramic substrate, which comprises the following steps: S1, after the raw materials are mixed, tape-cast and dried to obtain green porcelain sheets; S2, punching, surface printing, laminating, pressing, conducting, cutting, and sintering the green ceramic sheets to obtain a high-strength, wear-resistant multi-layer ceramic substrate.

[0026] As a further technical solution, the sintering temperature is 1500~1600℃, for example, it can be 1500℃, 1510℃, 1520℃, 1530℃, 1540℃, 1550℃, 1560℃, 1570℃, 1580℃, 1590℃, 1600℃, and preferably 1550℃; the sintering time is 3~4h, for example, it can be 3h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h, 4h, and preferably 3.5h.

[0027] The working principle and beneficial effects of the present invention are: The raw materials of the high-strength and wear-resistant multilayer ceramic substrate of the present invention use modified alumina obtained by modifying diphenylsilanediol and biphenyl compounds as raw materials, which solves the problem of agglomeration of alumina powder and improves the strength and wear resistance of the multilayer ceramic substrate. In the prior art, the hydroxyl groups formed on the surface of alumina powder easily form agglomerates through hydrogen bonding or condensation reactions, which seriously affects the strength and wear resistance of the multilayer ceramic substrate. In the present invention, diphenylsilanediol and biphenyl compounds are used as modifiers. The silanediol in diphenylsilanediol can react with the hydroxyl groups expressed by alumina, thereby introducing phenyl groups to the surface of alumina. The phenyl groups have a significant steric hindrance effect. The modified alumina is difficult to approach due to the mutual repulsion of the phenyl groups, which preliminarily alleviates the agglomeration of the alumina powder. The biphenyl compound has a rigid planar structure and can be adsorbed on the surface of the alumina modified by diphenylsilanediol through π-π stacking, further improving the strength and wear resistance of the multilayer 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: Alumina: Model AG-202G; Sodium polyacrylate: weight average molecular weight is 2100; Polyvinyl alcohol: model PVA1788; Magnesium oxide: average particle size is 1 μm.

[0030] Example 1 A method for preparing a high-strength wear-resistant multilayer ceramic substrate comprises the following steps: S1, after mixing 70 parts of aluminum oxide, 2 parts of sodium polyacrylate, 3 parts of dibutyl phthalate, 8 parts of polyvinyl alcohol, 8 parts of magnesium oxide, and 80 parts of water, the mixture was tape-casted and dried to obtain a green porcelain sheet; S2, punching, surface printing, laminating 30 layers of the green ceramic sheet, pressing, conducting the top and bottom, cutting, and sintering at 1550° C. for 3.5 hours to obtain a high-strength, wear-resistant multilayer ceramic substrate; The aluminum oxide is modified aluminum oxide, and the preparation method of the modified aluminum oxide comprises the following steps: dispersing diphenylsilanediol in 400 parts of toluene, adding 100 parts of aluminum oxide, mixing for 3 hours and then drying to obtain pretreated aluminum oxide; dispersing 4-methylbiphenyl in 400 parts of toluene, adding the pretreated aluminum oxide, mixing again for 3.5 hours and then drying to obtain modified aluminum oxide; wherein the total amount of diphenylsilanediol and 4-methylbiphenyl is 10 parts, and the mass ratio of diphenylsilanediol to 4-methylbiphenyl is 1:1.

[0031] Example 2 A method for preparing a high-strength wear-resistant multilayer ceramic substrate comprises the following steps: S1, after mixing 75 parts of aluminum oxide, 2.5 parts of sodium polyacrylate, 4 parts of dibutyl phthalate, 10 parts of polyvinyl alcohol, 9 parts of magnesium oxide, and 85 parts of water, tape-casting and drying to obtain a green porcelain sheet; S2, punching, surface printing, laminating 30 layers of the green ceramic sheet, pressing, conducting the top and bottom, cutting, and sintering at 1550° C. for 3.5 hours to obtain a high-strength, wear-resistant multilayer ceramic substrate; The aluminum oxide is modified aluminum oxide, and the preparation method of the modified aluminum oxide comprises the following steps: dispersing diphenylsilanediol in 400 parts of toluene, adding 100 parts of aluminum oxide, mixing for 3 hours and then drying to obtain pretreated aluminum oxide; dispersing 4-methylbiphenyl in 400 parts of toluene, adding the pretreated aluminum oxide, mixing again for 3.5 hours and then drying to obtain modified aluminum oxide; wherein the total amount of diphenylsilanediol and 4-methylbiphenyl is 10 parts, and the mass ratio of diphenylsilanediol to 4-methylbiphenyl is 1:1.

[0032] Example 3 A method for preparing a high-strength wear-resistant multilayer ceramic substrate comprises the following steps: S1, after mixing 80 parts of aluminum oxide, 3 parts of sodium polyacrylate, 5 parts of dibutyl phthalate, 12 parts of polyvinyl alcohol, 10 parts of magnesium oxide, and 90 parts of water, tape-casting and drying to obtain a green porcelain sheet; S2, punching, surface printing, laminating 30 layers of the green ceramic sheet, pressing, conducting the top and bottom, cutting, and sintering at 1550° C. for 3.5 hours to obtain a high-strength, wear-resistant multilayer ceramic substrate; The aluminum oxide is modified aluminum oxide, and the preparation method of the modified aluminum oxide comprises the following steps: dispersing diphenylsilanediol in 400 parts of toluene, adding 100 parts of aluminum oxide, mixing for 3 hours and then drying to obtain pretreated aluminum oxide; dispersing 4-methylbiphenyl in 400 parts of toluene, adding the pretreated aluminum oxide, mixing again for 3.5 hours and then drying to obtain modified aluminum oxide; wherein the total amount of diphenylsilanediol and 4-methylbiphenyl is 10 parts, and the mass ratio of diphenylsilanediol to 4-methylbiphenyl is 1:1.

[0033] Example 4 Compared with Example 1, the difference in Example 4 is that the mass ratio of diphenylsilanediol to 4-methylbiphenyl is 2:1.

[0034] Example 5 Compared with Example 4, Example 5 is different in that 4-methylbiphenyl is replaced by an equal amount of m-terphenyl.

[0035] Example 6 Compared with Example 4, Example 6 is different in that 4-methylbiphenyl is replaced by an equal amount of 4-tert-butylbiphenyl.

[0036] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that the preparation method of modified alumina is different. The preparation method of modified alumina in this comparative example includes the following steps: dispersing 10 parts of diphenylsilanediol in 400 parts of toluene, adding 100 parts of alumina, mixing for 3 hours and then drying to obtain modified alumina.

[0037] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that the preparation method of modified alumina is different. The preparation method of modified alumina in this comparative example includes the following steps: dispersing 10 parts of 4-methylbiphenyl in 400 parts of toluene, adding 100 parts of alumina, mixing for 3.5 hours and then drying to obtain modified alumina.

[0038] Comparative Example 3 A method for preparing a high-strength wear-resistant multilayer ceramic substrate comprises the following steps: S1, after mixing 70 parts of aluminum oxide, 2 parts of sodium polyacrylate, 3 parts of dibutyl phthalate, 8 parts of polyvinyl alcohol, 8 parts of magnesium oxide, and 80 parts of water, the mixture was tape-casted and dried to obtain a green porcelain sheet; S2. Punching, surface printing, laminating 30 layers, pressing, conducting top and bottom, cutting, and sintering at 1550° C. for 3.5 hours to obtain a high-strength, wear-resistant multilayer ceramic substrate.

[0039] Experimental Example 1 The high-strength, wear-resistant multilayer ceramic substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested according to the following test methods: 1. Bending strength: Test the bending strength of the sample according to the test method (three-point bending method) specified in GB / T 6569-2006 "Test method for bending strength of fine ceramics".

[0040] 2. Wear rate: A ball-on-disc friction and wear test was conducted on the specimens. The tribological properties of the specimens were tested using a CFT-I material surface performance comprehensive tester (Lanzhou Zhongke Kaihua Technology Development Co., Ltd.). The wear rate of the specimens was tested under a load of 5N.

[0041] The test results are shown in Table 1: Table 1 Performance test results of high-strength wear-resistant multilayer ceramic substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0042] As can be seen from Table 1, when alumina is first modified with diphenylsilanediol and then modified with a biphenyl compound, the strength and wear resistance of the multilayer ceramic substrate can be further improved.

[0043] 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. A high-strength, wear-resistant multilayer ceramic substrate, characterized in that: The invention comprises the following raw materials in parts by weight: 70-80 parts of aluminum oxide, 2-3 parts of dispersant, 3-5 parts of plasticizer, 8-12 parts of binder, 8-10 parts of sintering aid and 80-90 parts of water. The aluminum oxide is modified aluminum oxide, which is obtained by modifying aluminum oxide with a modifier. The modifier comprises diphenylsilanediol and a biphenyl compound.

2. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The mass ratio of the diphenylsilanediol to the biphenyl compound is 1-2:

1.

3. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The biphenyl compound includes one or more of m-terphenyl, 4-methylbiphenyl, and 4-tert-butylbiphenyl.

4. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The preparation method of the modified alumina comprises the following steps: dispersing diphenylsilanediol in toluene, adding alumina, performing a first mixing and then drying to obtain pretreated alumina; dispersing a biphenyl compound in toluene, adding the pretreated alumina, performing a second mixing and then drying to obtain modified alumina.

5. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The dispersant includes one or both of sodium polyacrylate and polyacrylic acid.

6. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The plasticizer includes one or both of dibutyl phthalate and dioctyl phthalate.

7. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The binder is polyvinyl alcohol.

8. The high-strength, wear-resistant multi-layer ceramic substrate according to claim 1, characterized in that: The sintering aid includes one or more of magnesium oxide, calcium oxide, and titanium dioxide.

9. A method for preparing a high-strength, wear-resistant multilayer ceramic substrate, for preparing a high-strength, wear-resistant multilayer ceramic substrate according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, after the raw materials are mixed, tape-cast and dried to obtain green porcelain sheets; S2, punching, surface printing, laminating, pressing, conducting, cutting, and sintering the green ceramic sheets to obtain a high-strength, wear-resistant multi-layer ceramic substrate.

10. The method for preparing a high-strength wear-resistant multi-layer ceramic substrate according to claim 9, characterized in that: The sintering temperature is 1500-1600° C., and the sintering time is 3-4 hours.

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