Ceramic slurry and ceramic product

Abstract

The invention belongs to the field of ceramic materials, and particularly discloses ceramic slurry and a ceramic product. The ceramic slurry comprises the following components in parts by mass: 60-70 parts of ceramic powder, 0.8-3 parts of a fluxing agent, 3-5 parts of a binder, 1.8-2.5 parts of a plasticizer, 0.1-0.8 part of a defoaming agent and 20-30 parts of a solvent, and the defoaming agent comprises polyether modified polysiloxane. The polyether modified polysiloxane is used as the defoaming agent, can be quickly dispersed in the ceramic slurry, can also quickly eliminate bubbles in the ceramic slurry, reduces the influence of potential residues of organic silicon on the performance of a ceramic product, shows good compatibility in a complex system of the ceramic slurry, is quick in foam inhibition and defoaming, and can be used for preparing the ceramic slurry. And no negative influence is generated on dispersion and rheology of the ceramic slurry.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials, specifically relating to a ceramic slurry and ceramic products. Background Technology

[0002] The key to ceramic preparation is obtaining a uniformly and stably dispersed ceramic slurry. Ceramic slurries typically include components such as ceramic powder, binder, plasticizer, dispersant, sintering aid, and solvent. Depending on production requirements, additives such as grinding aids, colorants, wetting agents, and coupling agents may also be added. However, with the use of various additives, the ceramic slurry has high surface activity, leading to difficulties in removing bubbles generated during stirring, which can subsequently cause a series of production problems and abnormal product performance.

[0003] Common defoaming methods include physical stirring, vacuum settling, and the use of defoamers. However, physical stirring and vacuum settling commonly suffer from uneven defoaming and poor defoaming effects. Among various types of defoamers, silicone defoamers are the most effective, exhibiting low surface tension and strong foam suppression and defoaming capabilities. Their working principle involves rapid dispersion in the ceramic slurry, reducing the surface energy of bubbles and accelerating their collapse. However, silicone defoamers leave a significant amount of residual silicon during sintering, leading to a series of problems such as reduced strength, increased brittleness, decreased insulation performance, increased dielectric loss, and decreased thermal conductivity in the finished ceramic product. This severely impacts the application of silicone defoamers in ceramic slurries. Therefore, existing defoaming methods generally suffer from uneven defoaming, difficulty in controlling the type and amount of defoamer used, and defoamer residue during sintering, all of which affect the various properties of the prepared ceramic products. Summary of the Invention

[0004] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a ceramic slurry.

[0005] The second objective of this invention is to provide the application of the above-mentioned ceramic slurry in the preparation of ceramic substrates.

[0006] The third objective of this invention is to provide a ceramic product.

[0007] The fourth objective of this invention is to provide an electronic product.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] The first aspect of the present invention provides a ceramic slurry comprising the following components in parts by weight: 60-70 parts ceramic powder, 0.8-3 parts flux, 3-5 parts binder, 1.8-2.5 parts plasticizer, 0.1-0.8 parts defoamer, and 20-30 parts solvent, wherein the defoamer comprises polyether-modified polysiloxane.

[0010] This invention uses polyether-modified polysiloxane as a defoamer for ceramic slurries. It possesses strong defoaming capabilities, disperses rapidly in the ceramic slurry, and quickly eliminates air bubbles. Compared to silicone-based defoamers, polyether-modified polysiloxane significantly reduces the residual silicone content in ceramic products made from ceramic slurries. It exhibits good compatibility in complex ceramic slurry systems, provides rapid foam suppression and defoaming, and does not negatively impact the dispersion and rheology of the ceramic slurry.

[0011] In some embodiments of the present invention, the mass fraction of the ceramic powder is selected from any value of 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, or a range formed by any two of these values.

[0012] In some embodiments of the present invention, the average particle size of the ceramic powder is 0.1 to 1 μm; in some embodiments of the present invention, the average particle size of the ceramic powder is any value or a range formed by any two of 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, and 1 μm.

[0013] In some embodiments of the present invention, the mass fraction of the defoamer is selected from any value of 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, or a range formed by any two of these values.

[0014] In some embodiments of the present invention, the number average molecular weight of the polyether-modified polysiloxane is 1000-15000 Da; in some embodiments of the present invention, the number average molecular weight of the polyether-modified polysiloxane is any value or a range formed by any two of the following: 1000 Da, 2000 Da, 3000 Da, 4000 Da, 5000 Da, 6000 Da, 7000 Da, 8000 Da, 9000 Da, 10000 Da, 11000 Da, 12000 Da, 13000 Da, 14000 Da, and 15000 Da.

[0015] In this invention, the polyether-modified polysiloxane has the structure shown in Formula I:

[0016]

[0017] In some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane (i.e., the molar ratio of n to m in Formula I) is (0.25–1.5):1; in some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments is any value or a range formed by any two of the following: 0.25:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1. In the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane is obtained by combining infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and silicon nuclear magnetic resonance spectroscopy.

[0018] This invention adjusts the number-average molecular weight of the defoamer, the ratio of polyether segments to polysiloxane segments, and optimizes the composition of the defoamer to make the defoamer meet the above conditions. At this time, the defoamer has a low number-average molecular weight, strong hydrophobicity, good chemical stability, and excellent defoaming performance. At the same time, the use of the defoamer has little effect on the rheological properties and dispersibility of the ceramic slurry, which can be ignored.

[0019] In some embodiments of the present invention, the defoamer is a mixture of polyether-modified polysiloxane A and polyether-modified polysiloxane B, wherein the mass ratio of polyether-modified polysiloxane A to polyether-modified polysiloxane B is (0.5-1):1; in some embodiments of the present invention, the mass ratio of polyether-modified polysiloxane A to polyether-modified polysiloxane B is any value or a range formed by any two of the following: 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1:1.

[0020] In some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane A is (0.25 to 0.8):1, and is not 0.8:1; in some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane A is any value of 0.25:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.799:1, or a range formed by any two of these values.

[0021] In some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane B is (0.8–1.5):1; in some embodiments of the present invention, the block molar ratio of polyether segments to polysiloxane segments in the polyether-modified polysiloxane B is any value or a range formed by any two of the following: 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1, 1.5:1.

[0022] This invention utilizes two polyether-modified polysiloxanes (polyether-modified polysiloxane A and polyether-modified polysiloxane B) with different block ratios. Polyether-modified polysiloxane A, with a relatively higher polysiloxane content, enhances defoaming ability, while polyether-modified polysiloxane B, with a relatively higher polyether content, improves the compatibility of polyether-modified polysiloxane A with the system and enhances dispersibility. Compared to using a single polyether-modified polysiloxane, the combination of these two polyether-modified polysiloxanes results in better system compatibility, lower silicone residue, and superior defoaming effect. This further combines the properties of both polysiloxane and polyether to rapidly eliminate bubbles in ceramic slurries while reducing silicone residue, thus improving the performance of ceramic products made from the ceramic slurry.

[0023] In some embodiments of the present invention, the ceramic powder is selected from at least one of alumina, silicon oxide, and zirconium oxide.

[0024] In some embodiments of the present invention, the flux includes at least one of SiO2, BaO, TiO2, CaO, MnO2, Y2O3, and La2O3; in some embodiments of the present invention, the flux includes at least three of BaO, SiO2, TiO2, CaO, MnO2, Y2O3, and La2O3.

[0025] In some embodiments of the present invention, the mass fraction of the flux is selected from any value or a range formed by any two of 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, and 3 parts.

[0026] In some embodiments of the present invention, the adhesive includes at least one of polyvinyl butyral, polyphenylene ether sulfone, polyether sulfone, and polymethyl methacrylate.

[0027] In some embodiments of the present invention, the mass fraction of the adhesive is selected from any value of 3 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, 5 parts, or a range formed by any two of these values.

[0028] In some embodiments of the present invention, the plasticizer includes at least one selected from dioctyl phthalate, dibutyl phthalate, glycerin, ethylene glycol, and triethylene glycol acetate.

[0029] In some embodiments of the present invention, the plasticizer is selected from any value of 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, or a range formed by any two of these values.

[0030] In some embodiments of the present invention, the solvent includes at least one selected from ethanol, isopropanol, methanol, acetone, methyl ethyl ketone, toluene, xylene, ethyl acetate, n-hexane, and cyclohexane.

[0031] In some embodiments of the present invention, the mass fraction of the solvent is selected from any value of 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, or a range formed by any two of these values.

[0032] In some embodiments of the present invention, the ceramic slurry is prepared by mixing and grinding various raw materials including ceramic powder, flux, binder, plasticizer, defoamer and solvent.

[0033] In some embodiments of the present invention, the mixing is performed by mechanical stirring.

[0034] In some embodiments of the present invention, the grinding is performed using ball milling.

[0035] The second aspect of the present invention provides the application of the ceramic slurry described in the first aspect of the present invention in the preparation of ceramic substrates, comprising the following steps:

[0036] The ceramic slurry is cast and dried to obtain raw ceramic sheets;

[0037] The ceramic green sheet is stamped into shape, and after debinding and sintering, the ceramic substrate is obtained.

[0038] In some embodiments of the present invention, the temperature for discharging the adhesive is 400–600°C; in some embodiments of the present invention, the temperature for discharging the adhesive is any value or a range formed by any two of the following: 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, and 600°C.

[0039] In some embodiments of the present invention, the sintering temperature is 1300–1700°C; in some embodiments of the present invention, the sintering temperature is any value or a range formed by any two of the following: 1300°C, 1320°C, 1340°C, 1360°C, 1380°C, 1400°C, 1420°C, 1440°C, 1460°C, 1480°C, 1500°C, 1520°C, 1540°C, 1560°C, 1580°C, 1600°C, 1620°C, 1640°C, 1660°C, 1680°C, and 1700°C.

[0040] A third aspect of the present invention provides a ceramic product formed from the ceramic slurry described in the first aspect of the present invention, or comprising a component formed from the ceramic slurry described in the first aspect of the present invention.

[0041] In some embodiments of the present invention, the ceramic product includes a ceramic substrate, a multilayer ceramic capacitor, or a multilayer ceramic inductor.

[0042] A fourth aspect of the present invention provides an electronic product comprising the ceramic product described in the first aspect of the present invention.

[0043] The beneficial effects of this invention are: This invention uses polyether-modified polysiloxane as a defoamer, which can not only be quickly dispersed in ceramic slurry, but also quickly eliminate bubbles in ceramic slurry, while reducing the potential impact of organosilicon residue on the performance of ceramic products. It exhibits good compatibility in the complex system of ceramic slurry, and the foam suppression and defoaming are rapid without negatively affecting the dispersion and rheology of ceramic slurry.

[0044] Furthermore, the ceramic slurry of this invention can be used to prepare ceramic substrates, resulting in ceramic substrates with excellent density, high strength, high insulation resistance, low dielectric loss, and high thermal conductivity. These substrates can be used in precision and miniaturized electronic products. Specific properties of the ceramic substrates include a density of 3.76–3.89 g / cm³. 3 Its strength is 585–607 MPa, and its insulation resistance is 3.3–4.3 × 10⁻⁶ MPa. 12 Ω, dielectric loss is 2~2.9×10 -4 Its thermal conductivity is 25.1–26.1 W / m·K. Detailed Implementation

[0045] The following examples provide a more detailed description of the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0046] The polyether-modified polysiloxanes used in the following examples can be commercially available products or synthesized using existing methods. For example, they can be synthesized via the following route: In a four-necked flask, the reactants, including hydrogen-containing silicone oil, terminal allyl polyoxyethylene ether, and toluene, are first azeotropically dehydrated. Then, using chloroplatinic acid as a catalyst, the mixture is heated to 100°C under a nitrogen atmosphere and reacted for 4–4.5 h. After removing the solvent, the polyether-modified polysiloxane is obtained. The molar ratio of polyether segments to polysiloxane segments can be controlled by adjusting the feed ratio of the reactants. The molar ratio of polyether segments to polysiloxane segments can be characterized by FT-IR (infrared spectroscopy), H-NMR, and Si-NMR (nuclear magnetic resonance).

[0047] Example 1

[0048] This example provides an alumina ceramic slurry, which is composed of the following components in parts by weight: 60 parts alumina powder, 2 parts flux, 5 parts binder, 2.5 parts plasticizer, 0.5 parts defoamer and 30 parts solvent. The specific formula is shown in Table 1.

[0049] The alumina powder has a particle size of 0.1–1 μm and an average particle size of 0.4 μm.

[0050] The flux is CaO, TiO2 and Y2O3, and the mass ratio of CaO, TiO2 and Y2O3 is 1:0.5:0.2;

[0051] The adhesive is polyvinyl butyral with a number average molecular weight of 40,000 Da;

[0052] The plasticizer is dioctyl phthalate;

[0053] The defoamer is a polyether-modified polysiloxane with a number average molecular weight of 3991 Da, wherein the block molar ratio of polyether segments to polysiloxane segments is 0.7:1.

[0054] The solvent is a mixture of toluene and acetone, with a mass ratio of toluene to acetone of 1:1.

[0055] The specific composition of flux, defoamer and solvent is shown in Table 2.

[0056] The above-mentioned ceramic slurry is prepared by mixing and dispersing the raw materials through ball milling.

[0057] This example also provides an alumina ceramic substrate, which is prepared using the following method:

[0058] The above alumina ceramic slurry is cast and dried to form alumina ceramic green body;

[0059] The alumina ceramic green body is then stamped and formed, debinded at 500°C for 4 hours, and sintered at 1500°C for 24 hours to form the alumina ceramic substrate.

[0060] The formulations of the alumina ceramic slurries in Examples 2-21 and Comparative Examples 1-2 are shown in Table 1, and the specific compositions of the cosolvents, defoamers and solvents used in the alumina ceramic slurries are shown in Table 2.

[0061] Table 1 Formulation of alumina ceramic slurry

[0062]

[0063]

[0064] Table 2. Ratio of cosolvent, defoamer, and solvent

[0065]

[0066]

[0067]

[0068]

[0069] In Table 2, A:B refers to the mass ratio of polyether-modified polysiloxane A to polyether-modified polysiloxane B.

[0070] Alumina ceramic slurries as described in Examples 2-21 and Comparative Examples 1-3 were prepared according to the preparation method in Example 1, and then the alumina ceramic slurries were used to prepare alumina ceramic substrates.

[0071] Performance testing

[0072] The defoaming time and viscosity of the alumina ceramic slurry were tested respectively. Then, the ceramic strength, ceramic density, insulation performance, dielectric loss, and thermal conductivity of the alumina ceramic substrate were tested. The specific test methods are as follows:

[0073] Defoaming time: Take a certain amount of alumina ceramic slurry, stir it at 1000 r / min for 1 min, and record the time when 95% of the bubbles disappear;

[0074] Slurry viscosity: Insert the viscometer probe into the alumina ceramic slurry and start the measurement. Read the viscosity value at 30℃.

[0075] Ceramic strength: Fix the alumina ceramic substrate test sample in the strength tester fixture, ensure the sample is horizontal, turn on the strength tester, and record the number on the table when the pin breaks through the sample;

[0076] Ceramic density: The density of the ceramic was tested using a water displacement density meter.

[0077] Insulation resistance: Apply a DC voltage to the surface of a dry and clean alumina ceramic substrate sample using a megohmmeter, hold for 1 minute, and then read the resistance value.

[0078] Dielectric loss: Polish both sides of the alumina ceramic substrate sample and coat it with a uniform electrode. Then, clamp the sample with a parallel plate electrode and measure the dielectric loss value at a set frequency using an LCR meter.

[0079] Thermal conductivity: The alumina ceramic substrate sample was polished and coated to enhance heat absorption and infrared emission. The back of the sample was irradiated with a laser flash meter, and the temperature rise curve of the front was recorded by an infrared detector. The thermal conductivity was calculated by combining the specific heat capacity and density data.

[0080] The performance data of the alumina ceramic slurry of Examples 1-16 and Comparative Examples 1-3 and the alumina ceramic substrates made from the alumina ceramic slurry, obtained according to the above test methods, are shown in Table 3 below.

[0081] Table 3 Performance data of alumina ceramic slurry and alumina ceramic substrate

[0082]

[0083]

[0084] As shown in Table 3, the alumina ceramic slurry in Examples 1-16 uses polyether-modified polysiloxane as a defoamer, resulting in a shorter defoaming time, better defoaming performance, and minimal impact on slurry viscosity. This leads to better density, strength, insulation properties, dielectric loss, and thermal conductivity of the resulting ceramic substrates. Specifically, the density of the ceramic substrates is 3.76–3.89 g / cm³. 3 Its strength is 585–607 MPa, and its insulation resistance is 3.3–4.3 × 10⁻⁶ MPa. 12 Ω, dielectric loss is 2~2.9×10 -4 Its thermal conductivity is 25.1–26.1 W / m·K.

[0085] Compared with Examples 1-16, Comparative Example 3 did not add defoamer, while Comparative Example 1 used a polyether-based defoamer. It can be seen that the defoaming performance of polyether-based defoamers is lower than that of polyether-modified polysiloxane. Due to the untimely defoaming in Comparative Examples 3 and 1, the ceramic porosity is high, the ceramic substrate strength is poor, and the ceramic density is low. Comparative Example 2 used an organosilicon-based defoamer. Although the defoaming performance is better, it produces silicon residue, which affects the strength and thermal conductivity of the ceramic substrate.

[0086] Examples 1-5 discussed the effect of the segment molar ratio of polyether segments and polysiloxane segments. It can be seen that a segment molar ratio in the range of (0.5-1.5):1 is preferred. When the ratio is below 0.5:1, silicon residue is easily generated, which affects the strength of the ceramic substrate; when the ratio is above 1.5:1, the effect of polysiloxane modification is not obvious, and the defoaming effect is not significantly improved.

[0087] Examples 9-12 discussed the effect of the number-average molecular weight of the defoamer. It can be seen that a number-average molecular weight between 1000-10000 Da is preferred. When the number-average molecular weight is higher than 10000 Da, it will have a greater impact on the rheological properties of the ceramic slurry.

[0088] Examples 13-16 discussed the effect of the amount of defoamer added. It can be seen that the amount of defoamer added is more suitable between 0.1 and 0.8 parts by mass. When the amount of defoamer added exceeds 0.8 parts by mass, it will lead to a large amount of residual silicon element, which will affect the strength of the ceramic substrate.

[0089] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A ceramic slurry, characterized in that: The components include the following parts by weight: 60-70 parts ceramic powder, 0.8-3 parts flux, 3-5 parts binder, 1.8-2.5 parts plasticizer, 0.1-0.8 parts defoamer, and 20-30 parts solvent, wherein the defoamer includes polyether-modified polysiloxane.

2. The ceramic slurry according to claim 1, characterized in that: The polyether-modified polysiloxane has at least one of the following characteristics: (a1) The number average molecular weight of the polyether-modified polysiloxane is 1000-15000 Da; (a2) In the polyether-modified polysiloxane, the block molar ratio of polyether segments to polysiloxane segments is (0.25~1.5):

1.

3. The ceramic slurry according to claim 1, characterized in that: The defoamer is a mixture of polyether-modified polysiloxane A and polyether-modified polysiloxane B, with a mass ratio of (0.5-1):

1.

4. The ceramic slurry according to claim 3, characterized in that: In the polyether-modified polysiloxane A, the block molar ratio of polyether segments to polysiloxane segments is (0.25–0.8):1, and is not 0.8:1; and / or, in the polyether-modified polysiloxane B, the block molar ratio of polyether segments to polysiloxane segments is (0.8–1.5):

1.

5. The ceramic slurry according to claim 1, characterized in that: The ceramic powder is selected from at least one of alumina, silicon dioxide, and zirconium oxide; And / or, the flux includes at least one of SiO2, BaO, TiO2, CaO, MnO2, Y2O3, and La2O3; And / or, the adhesive comprises at least one of polyvinyl butyral, polyphenylene ether sulfone, polyether sulfone, and polymethyl methacrylate; And / or, the plasticizer includes at least one of dioctyl phthalate, dibutyl phthalate, glycerin, ethylene glycol, and triethylene acetate; And / or, the solvent includes at least one of ethanol, isopropanol, methanol, acetone, methyl ethyl ketone, toluene, xylene, ethyl acetate, n-hexane, and cyclohexane.

6. The application of the ceramic slurry according to any one of claims 1 to 5 in the preparation of ceramic substrates, characterized in that: Includes the following steps: The ceramic slurry is cast and dried to obtain raw ceramic sheets; The ceramic green sheet is stamped into shape, and after debinding and sintering, the ceramic substrate is obtained.

7. The application according to claim 6, characterized in that: The temperature for discharging the adhesive is 400–600℃; And / or, the sintering temperature is 1300–1700°C.

8. A ceramic product, characterized in that: It is formed by molding the ceramic slurry according to any one of claims 1 to 5, or includes a component formed by molding the ceramic slurry according to any one of claims 1 to 5.

9. The ceramic product according to claim 8, characterized in that: The ceramic products include ceramic substrates, multilayer ceramic capacitors, or multilayer ceramic inductors.

10. An electronic product, characterized in that: Includes the ceramic product as described in claim 8 or 9.

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