Ceramic slurry as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of ceramic slurry, and particularly relates to ceramic slurry and a preparation method and application thereof.The ceramic slurry comprises inorganic components and organic components, the inorganic components comprise inorganic additives and glass powder, the inorganic additives comprise Al2O3, ZrO2 and Y2O3, and the organic components comprise modified acrylic resin, organic solvent and auxiliaries. By controlling the relative content of carboxyl and ester groups in the modified acrylic resin and utilizing the polarity difference of functional groups, selective adsorption of inorganic powder is realized, so that the dispersion uniformity of the powder in the ceramic slurry is remarkably improved, segregation of yttrium oxide is effectively inhibited, and the service life of the ceramic slurry is prolonged. Therefore, monoclinic-phase zirconium oxide, tetragonal-phase zirconium oxide and cubic-phase zirconium oxide with a proper proportion can be formed in the sintered ceramic substrate, further the bending strength of the ceramic substrate is remarkably improved, and the ceramic substrate is particularly suitable for manufacturing miniaturized and thin electronic components.

Description

Technical Field

[0001] This invention belongs to the field of ceramic slurry technology, specifically relating to a ceramic slurry, its preparation method, and its application. Background Technology

[0002] In recent years, as electronic devices such as mobile phones and laptops have continued to become smaller and thinner, their internal electronic components also need to be miniaturized and thinner accordingly. These components are usually composed of a ceramic package substrate and the sealed electronic components inside. However, after miniaturization and thinning, the bending strength of the ceramic package substrate often decreases.

[0003] Ceramic encapsulation substrates consist of a ceramic substrate and a conductive layer formed on the ceramic substrate. To improve the bending strength of ceramic encapsulation substrates, a common approach is to add zirconium oxide and yttrium oxide to the raw material (alumina ceramic slurry) of the ceramic substrate. After high-temperature sintering, the stable monoclinic zirconium oxide transforms into metastable tetragonal and cubic zirconium oxide. Yttrium oxide can inhibit the transformation of tetragonal and cubic zirconium oxide back to the monoclinic phase during cooling. When the ceramic encapsulation substrate is subjected to external forces, the tetragonal zirconium oxide can absorb energy through phase transformation and transform into monoclinic zirconium oxide, thereby improving fracture toughness and bending strength. Simultaneously, when cracks occur inside the encapsulation substrate, the cubic zirconium oxide can effectively prevent crack propagation, further enhancing the bending strength of the substrate.

[0004] However, during the preparation of ceramic substrates, the inorganic powders with multi-sized particles often exhibit poor dispersion in the raw material slurry process, leading to yttrium oxide segregation. This results in an imbalance in the content of the three zirconium oxide crystal forms in the sintered ceramic substrate, ultimately failing to effectively improve the bending strength of the ceramic substrate and ceramic packaging base. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a ceramic slurry that effectively improves the dispersion uniformity of multi-sized powders by optimizing the interaction between inorganic and organic components, suppresses yttrium oxide segregation, thereby ensuring that the ceramic substrate obtains a suitable zirconium oxide crystalline phase composition and microstructure after sintering, and ultimately achieves an effective improvement in flexural strength.

[0006] The first aspect of the present invention provides a ceramic slurry, wherein the raw materials of the ceramic slurry include inorganic components and organic components, the inorganic components include inorganic additives and glass powder, the inorganic additives include Al2O3, ZrO2 and Y2O3, and the organic components include modified acrylic resin, organic solvent and additives. The modified acrylic resin has the following structural formula: Wherein, 0.25≤m≤0.55, 0.1≤n≤0.5, 0.15≤p≤0.55, 0.1≤q≤0.4, m+n+p+q=1, and a=q / (m+n+p), 0.16≤a≤0.36.

[0007] m, n, p, and q represent the mass fractions of each structural unit of the modified acrylic resin.

[0008] This invention achieves selective adsorption of inorganic powders by controlling the relative content of carboxyl groups and ester groups (methyl ester, ethyl ester, butyl ester) in modified acrylic resin and utilizing the difference in functional group polarity. This significantly improves the dispersion uniformity of powders in ceramic slurry and effectively suppresses the segregation of yttrium oxide. As a result, a suitable proportion of monoclinic zirconia, tetragonal zirconia, and cubic zirconia can be formed in the sintered ceramic substrate, thereby significantly improving the flexural strength of the ceramic substrate.

[0009] Specifically, if the relative content parameter a < 0.16, the resin lacks sufficient polar anchoring points and cannot effectively bind inorganic powder particles, resulting in poor dispersion of inorganic powder in the ceramic slurry and significant yttrium oxide segregation. Ultimately, the flexural strength of the sintered ceramic substrate cannot meet application requirements. If a > 0.36, the excessively strong intermolecular forces will hinder chain segment movement, resulting in excessive rigidity and insufficient toughness of the green body obtained by tape casting. At the same time, the excessive hydrophilicity of the resin makes it easy to absorb moisture from the air, causing the green body to expand and deform. More seriously, it will form a complex cross-linked structure, resulting in poor subsequent glue removal, introducing defects into the ceramic, and causing the strength performance of the final product to decrease and fail to meet application requirements.

[0010] The modified acrylic resin described in this invention can be commercially available or homemade, as long as it meets the above structural formula. In some embodiments, the preparation method of the modified acrylic resin includes the following steps: subjecting methyl methacrylate, ethyl acrylate, butyl methacrylate, and methacrylic acid monomer to an addition polymerization reaction to obtain the modified acrylic resin. The m, n, p, and q values ​​in the modified acrylic resin are controlled by adjusting the amount of methyl methacrylate, ethyl acrylate, butyl methacrylate, and methacrylic acid monomer added.

[0011] In some exemplary embodiments, the method for preparing the modified acrylic resin includes the following steps: S1. Weigh out methyl methacrylate, ethyl acrylate and butyl methacrylate, and prepare the initiator and solvent.

[0012] The initiator may be, for example, but is not limited to, benzoyl peroxide, and the amount of the initiator may be, for example, but is not limited to, 0.1% to 1% of the total mass of the ester monomers (methyl methacrylate, ethyl acrylate, and butyl methacrylate). The solvent may be, for example, but is not limited to, xylene, and the amount of the solvent may be, for example, 30% to 70% of the total mass of the system.

[0013] S2. Add solvent to the reaction vessel, start stirring, and then add the above ester monomers, initiator and solution to make the system mix evenly.

[0014] S3. Under the protection of an inert gas, the reaction system is heated to 80-120℃ and reacted for 3-8 hours to obtain polymer A. During the reaction, parameters such as temperature and pressure are monitored in real time using an online monitoring system, and samples are taken periodically to analyze the conversion rate and polymer molecular weight. When the expected conversion rate or molecular weight is reached or approaches the target value, heating is stopped, and the reaction system is allowed to cool naturally to room temperature.

[0015] S4. Add the methacrylic acid monomer to the above reaction system containing polymer A, and add a small amount of initiator.

[0016] The initiator may be, for example, but is not limited to, benzoyl peroxide, and the amount of the initiator may be, for example, but is not limited to, 0.1 to 1% of the total mass of methacrylic acid monomers.

[0017] S5. Under the protection of an inert gas, the temperature is raised to 80~120℃ and the reaction is carried out for 2~6 hours to allow the methacrylic acid monomer to undergo an addition polymerization reaction with polymer A. After the reaction is completed, the system is cooled and the solvent and unreacted monomers are removed by distillation or other methods to obtain the modified acrylic resin.

[0018] The m, n, p, and q values ​​in the modified acrylic resin can be confirmed using conventional detection methods in the art. For example, different types of functional groups can be identified by Fourier transform infrared spectroscopy (FTIR), the types and contents of functional groups can be identified by nuclear magnetic resonance spectroscopy (NMR), and the types of functional groups can be indirectly determined by thermogravimetric analysis-FTIR / TGA-MS. Finally, the types and contents of functional groups in the modified acrylic resin can be determined, and thus the m, n, p, and q values ​​in the modified acrylic resin can be obtained.

[0019] In some embodiments, the weight-average molecular weight M of the modified acrylic resin is... w The range is 180,000 to 360,000.

[0020] In some preferred embodiments, the weight-average molecular weight M of the modified acrylic resin is... w The range is 200,000 to 350,000.

[0021] The weight-average molecular weight M of the modified acrylic resin w It can be confirmed by conventional detection methods in the field, such as by gel permeation chromatography (GPC).

[0022] In some embodiments, the ceramic slurry comprises, by weight percentage, the following components: 85-90% inorganic components and 10-15% organic components.

[0023] In some embodiments, the inorganic components, based on the total mass of the inorganic components, comprise the following components by mass percentage: 60-75% Al₂O₃, 20-30% ZrO₂, 0.5-2% Y₂O₃, and 3-6% glass powder. The mass percentage of Al₂O₃ can be, for example, but is not limited to, a range of, or any two of the following: 60.0%, 60.5%, 61.0%, 61.5%, 62.0%, 62.5%, 63.0%, 63.5%, 64.0%, 64.5%, 65.0%, 65.5%, 66.0%, 66.5%, 67.0%, 67.5%, 68.0%, 68.5%, 69.0%, 69.5%, 70.0%, 70.5%, 71.0%, 71.5%, 72.0%, 72.5%, 73.0%, 73.5%, 74.0%, 74.5%, and 75.0%. The mass percentage of ZrO2 can be, for example, but not limited to, a range of 20.0%, 20.5%, 21.0%, 21.5%, 22.0%, 22.5%, 23.0%, 23.5%, 24.0%, 24.5%, 25.0%, 25.5%, 26.0%, 26.5%, 27.0%, 27.5%, 28.0%, 28.5%, 29.0%, 29.5%, 30.0%, or any two of these values. The mass percentage of Y2O3 can be, for example, but not limited to, a range of 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, or any two of these values. The mass percentage of the glass powder can be, for example, but not limited to, one or any two of the following: 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, 4.0%, 4.2%, 4.4%, 4.6%, 4.8%, 5.0%, 5.2%, 5.4%, 5.6%, 5.8%, 6.0%.

[0024] The average particle size of the Al2O3 is not particularly limited, but can be, for example, 0.1~5 μm, preferably 0.1~3 μm, and more preferably 0.5~2.5 μm. When the average particle size of Al2O3 is within the above-mentioned preferred range, the resulting ceramic slurry exhibits superior performance. Furthermore, the inventors have discovered that, based on the total mass of Al2O3, when Al2O3 with a particle size of 1~2 μm accounts for 70~80% of the total mass of Al2O3, the resulting ceramic slurry exhibits superior performance. This is because the smaller particle size in the Al2O3 system can fill the voids created by the accumulation of larger particle size, thereby increasing the packing density of the powder and the density of the green body. This results in a more densely structured ceramic substrate during subsequent sintering, significantly improving the flexural strength of the ceramic substrate.

[0025] The average particle size of the Al2O3 can be confirmed by conventional detection methods in the art, such as by laser particle size analyzer. The mass percentage of Al2O3 with a particle size of 1~2μm in the total mass of Al2O3 can also be confirmed by conventional detection methods in the art, such as by laser particle size analyzer.

[0026] The average particle size of the ZrO2 is not particularly limited, and can be, for example, 0.1~2μm, preferably 0.4~1.8μm, and more preferably 0.5~1.5μm. The average particle size of the ZrO2 can be confirmed by conventional detection methods in the art, such as by laser particle size analyzer.

[0027] The average particle size of the Y₂O₃ is not particularly limited, and can be, for example, 0.1~2 μm, preferably 0.4~1.6 μm, and more preferably 0.5~1.5 μm. The average particle size of the Y₂O₃ can be confirmed by conventional detection methods in the art, such as by laser particle size analyzer.

[0028] The average particle size of the glass powder is not particularly limited, but can be, for example, 0.2~2μm, preferably 0.5~1.5μm, and more preferably 0.6~1.1μm. The average particle size of the glass powder can be confirmed by conventional detection methods in the art, such as by laser particle size analyzer.

[0029] In some embodiments, the organic components, based on the total mass of the organic components, comprise the following components in mass percentage: 10-35% modified acrylic resin, 60-85% organic solvent, and 1-10% additives. The mass percentage of the modified acrylic resin can be, for example, but not limited to, a range of 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or any two of these values. The mass percentage of the organic solvent can be, for example, but not limited to, a range of 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, or any two of these values. The mass percentage of the adjuvant can be, for example, but not limited to, one or any two of the following: 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%.

[0030] In some embodiments, the char residue of the modified acrylic resin after calcination at 1050°C for 18 hours is 0.1-0.5%, which can be obtained by testing with a carbon-sulfur analyzer. The principle of the carbon-sulfur analyzer is to calcine the modified acrylic resin in a high-temperature furnace by introducing oxygen, generating and releasing CO2 and / or SO2 gases, thereby separating carbon and sulfur elements from metal elements and their compounds. Then, the content of CO2 and / or SO2 is measured, and the carbon and sulfur content in the sample is calculated.

[0031] In some preferred embodiments, the char residue of the modified acrylic resin after calcination at 1050°C for 18 hours is 0.2-0.3%.

[0032] After sintering, resin residue exists at the ceramic grain boundaries in the form of flakes, fibers, or networks. When the resin residue ratio falls within the aforementioned range, the sintered ceramic substrate has an appropriate amount of residue. When microcracks form in the ceramic substrate and propagate to the residue region, the crack tip deflects, no longer extending in a straight line along its original path. The tortuous crack consumes more fracture energy. Simultaneously, the residue particles or fibers at both ends of the crack can bridge the gap, applying a closing stress behind the crack, thereby inhibiting its further propagation and ultimately significantly improving the flexural strength of the ceramic substrate. If the residue ratio is too low, the improvement effect on the flexural strength of the ceramic substrate is limited; if the residue ratio is too high, it will lead to increased porosity and decreased density of the ceramic substrate, which in turn reduces the flexural strength of the ceramic substrate.

[0033] In some embodiments, the inorganic additive further includes MoO3, with the mass percentage of MoO3 being 0.1% to 1.5% based on the total mass of the inorganic components. After sintering, MoO3 is reduced to Mo (black) and distributed throughout the material system. Adding MoO3 to the ceramic slurry can effectively control the color of the sintered ceramic body.

[0034] The average particle size of the MoO3 is not particularly limited, and can be, for example, 0.1~2 μm, preferably 0.3~1.0 μm, and more preferably 0.4~0.8 μm. The average particle size of the MoO3 can be confirmed by conventional detection methods in the art, such as by laser particle size analyzer.

[0035] In some embodiments, the glass powder comprises the following components by mass percentage: 50-70% SiO2, 15-25% CaCO3 and 15-25% talc. The mass percentage of SiO2 can be, for example, but not limited to, a range of 50.0%, 50.5%, 51.0%, 51.5%, 52.0%, 52.5%, 53.0%, 53.5%, 54.0%, 54.5%, 55.0%, 55.5%, 56.0%, 56.5%, 57.0%, 57.5%, 58.0%, 58.5%, 59.0%, 59.5%, 60.0%, 60.5%, 61.0%, 61.5%, 62.0%, 62.5%, 63.0%, 63.5%, 64.0%, 64.5%, 65.0%, 65.5%, 66.0%, 66.5%, 67.0%, 67.5%, 68.0%, 68.5%, 69.0%, 69.5%, 70.0%, or any two of these ranges. The mass percentage of CaCO3 can be, for example, but not limited to, one or any two of the following: 15.0%, 15.5%, 16.0%, 16.5%, 17.0%, 17.5%, 18.0%, 18.5%, 19.0%, 19.5%, 20.0%, 20.5%, 21.0%, 21.5%, 22.0%, 22.5%, 23.0%, 23.5%, 24.0%, 24.5%, 25.0%. The mass percentage of the talc powder can be, for example, but not limited to, one or any two of the following: 15.0%, 15.5%, 16.0%, 16.5%, 17.0%, 17.5%, 18.0%, 18.5%, 19.0%, 19.5%, 20.0%, 20.5%, 21.0%, 21.5%, 22.0%, 22.5%, 23.0%, 23.5%, 24.0%, 24.5%, 25.0%.

[0036] In some preferred embodiments, the glass powder comprises the following components by mass percentage: 51-67% SiO2, 16-25% CaCO3 and 17-25% talc.

[0037] In some embodiments, the talc powder includes at least one of raw talc powder and calcined talc powder.

[0038] In some preferred embodiments, the talc powder is raw talc powder.

[0039] In some embodiments, the organic solvent includes at least one of toluene, ethanol, xylene, butanone, isopropanol, and ethyl acetate.

[0040] In some embodiments, the additive includes at least one of a plasticizer and a dispersant.

[0041] In some embodiments, the plasticizer is present in a mass percentage of 0.5% to 5% based on the total mass of organic components. The mass percentage of the plasticizer may be, for example, but not limited to, a range of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, or any combination thereof.

[0042] In some preferred embodiments, the plasticizer is present in a mass percentage of 1.2% to 3.2% based on the total mass of organic components. The mass percentage of the plasticizer may be, for example, but not limited to, one or any two of the following: 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, and 3.2%.

[0043] In some embodiments, the mass percentage of the dispersant is 0.5% to 5% based on the total mass of the organic components. The mass percentage of the dispersant may be, for example, but is not limited to, a range of one or any two of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, and 5.0%.

[0044] In some preferred embodiments, the mass percentage of the dispersant, based on the total mass of the organic components, is 1.8% to 4.8%. The mass percentage of the dispersant can be, for example, but is not limited to, one or any two of the following: 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, and 4.8%.

[0045] In some embodiments, the dispersant includes at least one of stearic acid and acrylate.

[0046] In some embodiments, the plasticizer includes at least one of castor oil, polyethylene glycol, dioctyl phthalate (DOP), and dibutyl phthalate (DBP).

[0047] The second aspect of the present invention provides a method for preparing the above-mentioned ceramic slurry, comprising the following steps: mixing the raw materials evenly to obtain the ceramic slurry.

[0048] A third aspect of the present invention provides a ceramic substrate, wherein the raw material of the ceramic substrate includes the above-mentioned ceramic slurry.

[0049] In some embodiments, the ceramic substrate comprises an alumina primary crystalline phase and secondary crystalline phases. The secondary crystalline phases include monoclinic zirconia, tetragonal zirconia, and cubic zirconia, satisfying the condition: k = (t + c) / M, and 19 ≤ k ≤ 49. Wherein, t is the content of tetragonal zirconia in the secondary crystalline phase, c is the content of cubic zirconia in the secondary crystalline phase, and M is the content of monoclinic zirconia in the secondary crystalline phase. The types and contents of the crystalline phases in the ceramic substrate can be confirmed by conventional detection methods in the art, such as X-ray diffraction (XRD).

[0050] The fourth aspect of the present invention provides a method for preparing the above-mentioned ceramic substrate, comprising the following steps: using the above-mentioned ceramic slurry to form a ceramic green body by tape casting, and then subjecting the ceramic green body to debinding and sintering treatment to obtain the ceramic substrate.

[0051] In some embodiments, the debinding temperature is 350~550℃, the debinding time is 2~4h, the sintering temperature is 1250~1600℃, and the sintering time is 1~5h.

[0052] In some implementation schemes, the sintering temperature is 1450~1550℃ and the sintering time is 3~5h.

[0053] The fifth aspect of the present invention provides a ceramic packaging base, the ceramic packaging base comprising the above-mentioned ceramic substrate and conductive layer.

[0054] The sixth aspect of this invention provides the application of the above-mentioned ceramic packaging substrate in the fabrication of electronic components.

[0055] Compared with the prior art, the present invention has the following beneficial effects: This invention controls the relative content of carboxyl and ester groups in modified acrylic resin, and utilizes the difference in functional group polarity to achieve selective adsorption of inorganic powders, thereby significantly improving the dispersion uniformity of powders in ceramic slurry and effectively suppressing yttrium oxide segregation. This allows the sintered ceramic substrate to form a suitable proportion of monoclinic zirconia, tetragonal zirconia and cubic zirconia, thus significantly improving the flexural strength of the ceramic substrate, making it particularly suitable for the manufacture of miniaturized and thin electronic components. Detailed Implementation

[0056] The following detailed embodiments further illustrate the content of the present invention. These embodiments do not constitute a limitation on the scope of protection of the present invention. Non-essential modifications and adjustments made by others based on the concept of the present invention still fall within the scope of protection of the present invention. The raw materials, reagents, or devices used in the embodiments are all available from conventional commercial sources or can be obtained through existing technical methods. Unless otherwise specified, the experimental or testing methods are conventional methods in the art.

[0057] Examples 1-17 and Comparative Examples 1-2 The composition and content of the ceramic slurries described in Examples 1-17 and Comparative Examples 1-2 of this invention are shown in Tables 1-2. The only difference between the examples and the comparative examples is the type and ratio of the components; the preparation methods are the same.

[0058] The method for preparing ceramic slurry as described in Examples 1-17 and Comparative Examples 1-2 of this invention includes the following steps: The raw materials are mixed evenly according to the composition and content of the components shown in Tables 1-2 to obtain the ceramic slurry.

[0059] The ceramic slurries of Examples 1-17 and Comparative Examples 1-2 are applied to a ceramic substrate. The method for preparing the ceramic substrate includes the following steps: The ceramic slurries from Examples 1-17 and Comparative Examples 1-2 were cast into ceramic green bodies using a tape casting process. These green bodies were then subjected to debinding and sintering to obtain the ceramic substrate. The debinding temperature was 450°C, and the debinding time was 3 hours. The sintering temperature was 1500°C, and the sintering time was 4 hours. Test samples with dimensions of 50 mm x 5.5 mm x 3 mm were prepared from the ceramic substrate using laser scribing for subsequent performance testing.

[0060] In the components described in each embodiment and comparative example: The glass powder G1 comprises, by mass percentage, the following components: 51% SiO2, 25% CaCO3 and 24% talc, totaling 100%, and the average particle size of the glass powder G1 is 0.8 μm.

[0061] The glass powder G2 comprises, by mass percentage, the following components: 57.8% SiO2, 20.1% CaCO3 and 22.1% talc, totaling 100%, and the average particle size of the glass powder G2 is 0.8 μm.

[0062] The glass powder G3 comprises, by mass percentage, the following components: 66.7% SiO2, 16% CaCO3 and 17.3% talc, totaling 100%, and the average particle size of the glass powder G3 is 0.8 μm.

[0063] The average particle size of the Al2O3 is 1.6 μm. The average particle size of the Al2O3 particles used in each embodiment and comparative example is 1.6 μm. There are multiple batches of Al2O3 particles with an average particle size of 1.6 μm. The difference between the different batches is that the mass percentage of Al2O3 particles with a particle size of 1~2 μm in the total Al2O3 particles is different. For details, please refer to Tables 1~2.

[0064] The average particle size of the ZrO2 is 0.9 μm.

[0065] The average particle size of the Y2O3 is 0.8 μm.

[0066] The average particle size of the MoO3 is 0.5 μm.

[0067] The preparation method of modified acrylic resin includes the following steps: The modified acrylic resin is obtained by addition polymerization of methyl methacrylate, ethyl acrylate, butyl methacrylate, and methacrylic acid monomer. The m, n, p, and q values ​​in the modified acrylic resin are controlled by adjusting the amounts of methyl methacrylate, ethyl acrylate, butyl methacrylate, and methacrylic acid monomer added. Specifically: S1. Weigh out the ester monomers (methyl methacrylate, ethyl acrylate, butyl methacrylate), and prepare the initiator benzoyl peroxide (0.6% of the total mass of the ester monomers) and the solvent xylene (50% of the total mass of the system).

[0068] S2. In a reactor equipped with a stirrer, thermometer, and reflux condenser, first add the solvent, start stirring, and then add the above ester monomers and initiator solutions in sequence to make the system mix evenly.

[0069] S3. Under nitrogen protection, the reaction system is heated to 110℃ and reacted for 5 hours. During the reaction, parameters such as temperature and pressure are monitored in real time using an online monitoring system, and samples are taken periodically to analyze the conversion rate and polymer molecular weight. When the expected conversion rate or molecular weight is reached or approaches the target value, heating is stopped, and the reaction system is allowed to cool naturally to room temperature to obtain polymer A.

[0070] S4. Add the methacrylic acid monomer to the system after the above polymerization reaction, and at the same time add a small amount of initiator (0.3% of the amount of methacrylic acid monomer added).

[0071] S5. Under nitrogen protection, the temperature is raised to 80-120℃ and the reaction is carried out for 2-6 hours to induce an addition polymerization reaction between the methacrylic acid monomer and polymer A. After the reaction is complete, the system is cooled, and the solvent and unreacted monomers are removed by distillation or other methods to obtain the target modified acrylic resin.

[0072] The method for testing the char rate of the modified acrylic resin is as follows: after sampling the modified acrylic resin, it is calcined at 1050℃ for 18 hours, and its char rate is tested by a carbon-sulfur analyzer.

[0073] The weight-average molecular weight test method for the modified acrylic resin is as follows: its weight-average molecular weight M is determined by gel permeation chromatography (GPC). w .

[0074] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0075] Table 1 shows the component content of ceramic slurries in Examples 1-9. Table 2. Component content of ceramic slurries in Examples 10-17 and Comparative Examples 1-2 In Tables 1 and 2, the "content of each component in the ceramic slurry" is expressed based on the total mass of the ceramic slurry (i.e., 100%). For example, in Example 1, the inorganic component content is 88%, and the organic component content is 12%, meaning the ceramic slurry consists of 88% inorganic components and 12% organic components, totaling 100%. The "content of each component in the inorganic components" is expressed based on the total mass of the inorganic components (i.e., 100%). For example, in Example 1, the inorganic components consist of 68% alumina, 25% zirconium oxide, 1.2% yttrium oxide, 0.8% molybdenum oxide, and 5% glass powder G1, totaling 100%. The "content of each component in the organic components" is expressed based on the total mass of the organic components (i.e., 100%). For example, in Example 1, the organic components consist of 24% modified acrylic resin, 71% isopropanol, 2% castor oil, and 3% stearic acid, totaling 100%. "m, n, p, q" represent the mass fraction of the modified acrylic resin repeating unit, respectively. "M" w"Weight-average molecular weight of the modified acrylic resin" is obtained by gel permeation chromatography (GPC). "Carbon residue" is obtained by carbon-sulfur analysis after calcining the modified acrylic resin at 1050°C for 18 hours. "Content of Al2O3 particles with a particle size of 1-2 μm (%)" is based on the total mass of Al2O3 particles (i.e., 100%). For example, in Example 1, the content of Al2O3 particles with a particle size of 1-2 μm is 75%, which means that in the Al2O3 particles with an average particle size of 1.6 μm used in Example 1, Al2O3 particles with a particle size in the range of 1-2 μm account for 75% of the total mass of Al2O3 particles.

[0076] To verify the performance of the ceramic slurry and ceramic substrate described in this invention, the ceramic substrates obtained in each embodiment and comparative example were tested. The test content and methods are as follows: (1) Crystal phase test: The contents of monoclinic zirconia (M), tetragonal zirconia (t) and cubic zirconia (c) in the ceramic substrate were measured by X-ray diffraction (XRD). The k value was then calculated according to the formula: k=(t+c) / M. The calculation results are shown in Table 3.

[0077] (2) Bending strength: The universal testing machine was used to test the bending strength by the three-point bending method. The bending strength was considered to be qualified when it was ≥600MPa. The test results are shown in Table 3.

[0078] Table 3. k values ​​and flexural strengths of Examples 1-17 and Comparative Examples 1-2 As can be seen from Examples 1-17, the present invention controls the relative content of carboxyl and ester groups in the modified acrylic resin and utilizes the difference in functional group polarity to achieve selective adsorption of inorganic powders, thereby significantly improving the dispersion uniformity of powders in ceramic slurry and effectively suppressing the segregation of yttrium oxide. This allows the sintered ceramic substrate to form a suitable proportion of monoclinic zirconia, tetragonal zirconia and cubic zirconia, thereby significantly improving the bending strength of the ceramic substrate, which is especially suitable for the manufacture of miniaturized and thin electronic components.

[0079] Comparative Examples 1-17 and Comparative Examples 1-2 show that when the relative content of carboxyl and ester groups in the modified acrylic resin is outside the specified range, the performance of the resulting ceramic slurry is poor. This is because if a < 0.16, the resin lacks sufficient polar anchoring points and cannot effectively bind inorganic powder particles, resulting in poor dispersion of inorganic powder in the ceramic slurry and significant yttrium oxide segregation. Ultimately, the flexural strength of the sintered ceramic substrate cannot meet the application requirements. If a > 0.36, the excessively strong intermolecular forces hinder chain movement, resulting in excessive rigidity and insufficient toughness of the green body obtained by tape casting. At the same time, the excessive hydrophilicity of the resin easily adsorbs moisture from the air, causing the green body to expand and deform. More seriously, it can form a complex cross-linked structure, resulting in poor subsequent glue removal, introducing defects into the ceramic, and causing the strength performance of the final product to decrease and fail to meet the application requirements.

[0080] Comparing Examples 10-11 with other examples, it is evident that when Al₂O₃ with a particle size of 1-2 μm accounts for 70-80% of the total mass of Al₂O₃, the resulting ceramic slurry exhibits superior performance. This is because the smaller particles in the Al₂O₃ system can fill the voids created by the accumulation of larger particles, thereby increasing the packing density of the powder and the density of the green body. This results in a more compact ceramic substrate during subsequent sintering, significantly improving the flexural strength of the ceramic substrate.

[0081] Comparing Examples 12-13 with other examples, it is evident that when modified acrylic resin with a residual carbon content of 0.2-0.3% is used as the raw material, the resulting ceramic slurry exhibits superior performance. This is because, after sintering, the resin residual carbon exists in the form of flakes, fibers, or networks at the ceramic grain boundaries. When the resin residual carbon content falls within the aforementioned range, the sintered ceramic substrate possesses an appropriate amount of residual carbon. When microcracks develop in the ceramic substrate and propagate to the residual carbon region, the crack tip deflects, no longer extending in a straight line along the original path. The tortuous crack consumes more fracture energy. Simultaneously, the residual carbon particles or fibers at both ends of the crack can bridge the gap, applying a closing stress behind the crack, thereby inhibiting its further propagation and ultimately significantly improving the flexural strength of the ceramic substrate. If the residual carbon content is too low, the improvement effect on the flexural strength of the ceramic substrate is limited; if the residual carbon content is too high, it will lead to increased porosity and decreased density of the ceramic substrate, which in turn reduces the flexural strength of the ceramic substrate.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A ceramic slurry, characterized in that, The raw materials for the ceramic slurry include inorganic and organic components; The inorganic components include inorganic additives and glass powder; The inorganic additives include Al2O3, ZrO2, and Y2O3; The organic components include modified acrylic resin, organic solvents, and additives; The modified acrylic resin has the following structural formula: Wherein, 0.25≤m≤0.55, 0.1≤n≤0.5, 0.15≤p≤0.55, 0.1≤q≤0.4, m+n+p+q=1, and a=q / (m+n+p), 0.16≤a≤0.

36.

2. The ceramic slurry as described in claim 1, characterized in that, The ceramic slurry comprises the following components by mass percentage: 85-90% inorganic components and 10-15% organic components.

3. The ceramic slurry as described in claim 1, characterized in that, The inorganic components, based on the total mass of the inorganic components, include the following components by mass percentage: 60-75% Al2O3, 20-30% ZrO2, 0.5-2% Y2O3, and 3-6% glass powder.

4. The ceramic slurry as described in claim 1, characterized in that, Based on the total mass of the organic components, the organic components include the following components by mass percentage: 10-35% modified acrylic resin, 60-85% organic solvent and 1-10% additives; The modified acrylic resin satisfies at least one of the following characteristics (1) to (2): (1) The residual carbon content of the modified acrylic resin after calcination at 1050℃ for 18 hours is 0.1~0.5%; (2) The weight-average molecular weight M of the modified acrylic resin w The range is 180,000 to 360,000.

5. The ceramic slurry as described in claim 1, characterized in that, The inorganic additive also includes MoO3, and the mass percentage of MoO3 is 0.1-1.5% based on the total mass of the inorganic components.

6. The ceramic slurry as described in claim 1, characterized in that, The glass powder comprises the following components by mass percentage: 50-70% SiO2, 15-25% CaCO3 and 15-25% talc.

7. The ceramic slurry as described in claim 1, characterized in that, The organic solvent includes at least one of toluene, ethanol, xylene, butanone, isopropanol, and ethyl acetate; The additives include at least one of plasticizers and dispersants, and satisfy at least one of the following characteristics (1) to (4): (1) The plasticizer has a mass percentage of 0.5% to 5% based on the total mass of organic components; (2) The dispersant has a mass percentage of 0.5% to 5% based on the total mass of the organic components; (3) The dispersant includes at least one of stearic acid and acrylate; (4) The plasticizer includes at least one of castor oil, polyethylene glycol, dioctyl phthalate and dibutyl phthalate.

8. A ceramic substrate, characterized in that, The raw material for the ceramic substrate includes the ceramic slurry as described in any one of claims 1 to 7.

9. The ceramic substrate as described in claim 8, characterized in that, The ceramic substrate comprises an alumina primary crystalline phase and a secondary crystalline phase; the secondary crystalline phase includes monoclinic zirconia, tetragonal zirconia, and cubic zirconia. The subcrystalline phase satisfies: k = (t + c) / M, and 19 ≤ k ≤ 49; Where t is the content of tetragonal zirconium oxide in the secondary crystal phase, c is the content of cubic zirconium oxide in the secondary crystal phase, and M is the content of monoclinic zirconium oxide in the secondary crystal phase.

10. A method for preparing a ceramic substrate, characterized in that, The method includes using the ceramic slurry as described in any one of claims 1 to 7 to form a ceramic green body by tape casting, and then subjecting the ceramic green body to debinding and sintering treatments to obtain the ceramic substrate; The adhesive discharge temperature is 350~550℃, the adhesive discharge time is 2~4h, the sintering temperature is 1250~1600℃, and the sintering time is 1~5h.

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