Aluminum nitride ceramic slurry for tape casting and preparation method thereof

Abstract

The invention discloses aluminum nitride ceramic slurry for tape casting and a preparation method of the aluminum nitride ceramic slurry, and belongs to the technical field of ceramic tape casting. The invention provides aluminum nitride ceramic slurry for tape casting, which is prepared from the following raw materials in parts by mass: 75 to 85 parts of aluminum nitride ceramic powder, 1 to 4 parts of sintering aid, 10 to 15 parts of plasticizer, 3 to 10 parts of polyfunctional group acrylate monomer, 3 to 10 parts of low functional group acrylate monomer, 1 to 3 parts of initiator, 1 to 2 parts of dispersing agent and 10 to 15 parts of solvent. In addition, the invention also provides a preparation method of the ceramic slurry for tape casting. In addition, the invention also provides a preparation method of the aluminum nitride ceramic green body. According to the ceramic slurry provided by the invention, the aluminum nitride ceramic slurry can be obtained without subsequent punching.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic tape casting, and particularly relates to an aluminum nitride ceramic slurry for tape casting and a preparation method thereof. Background Art

[0002] Traditional aluminum nitride ceramic slurries for tape casting mainly consist of aluminum nitride ceramic powder, binder, plasticizer, solvent, and dispersant. Among them, the binder mainly consists of polyvinyl butyral (abbreviated as PVB), polyvinyl alcohol (PVA), etc., the plasticizer includes polyethylene glycol (PEG), polypropylene glycol (PPG), dibutyl phthalate (DBP), etc., and the solvent mainly consists of solvents such as toluene and ethanol. The aluminum nitride ceramic slurry flows onto the base tape through a doctor blade and forms a green body of aluminum nitride ceramic through solvent evaporation. Finally, the green body of the ceramic contains aluminum nitride ceramic powder, binder, and plasticizer. After debinding to remove the binder and plasticizer, an aluminum nitride ceramic substrate is finally formed through sintering.

[0003] Aluminum nitride ceramic substrates have high thermal conductivity, low expansion coefficient, high strength, high temperature resistance, chemical corrosion resistance, high resistivity, and low dielectric loss, and are ideal heat dissipation substrates and packaging materials for large-scale integrated circuits. High-temperature co-fired ceramics (HTCC) based on aluminum nitride ceramic substrates are suitable for high-temperature, high-power, and high-frequency applications, such as power electronics, sensors, and aerospace electronic devices. In the process of preparing aluminum nitride-based HTCC ceramic substrates, it includes steps such as green tape casting, screen printing, laminating, punching, cutting, debinding, firing, etc. Among them, during the processes of laminating, punching, and cutting, metal wires such as tungsten, molybdenum, and manganese are buried in the internal channels. However, the processes of punching and cutting are not only complex but also extremely likely to cause various defects such as deformation and cracking of the aluminum nitride ceramic green body, resulting in poor thermal, electrical, and mechanical properties of the finally prepared aluminum nitride-based HTCC ceramics. Therefore, there is an urgent need to develop an aluminum nitride ceramic slurry for tape casting that can avoid subsequent punching. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies and provide an aluminum nitride ceramic slurry for tape casting and a preparation method thereof, so as to solve the technical problem of how to obtain an aluminum nitride ceramic slurry for tape casting that can avoid subsequent punching in the prior art.

[0005] In order to achieve the above technical objectives, the technical solution of the present invention provides an aluminum nitride ceramic slurry for tape casting, and the raw materials, calculated by mass, include: 75-85 parts of aluminum nitride ceramic powder, 1-4 parts of sintering aid, 10-15 parts of plasticizer, 3-10 parts of multifunctional acrylate monomer, 3-10 parts of low-functional acrylate monomer, 1-3 parts of initiator, 1-2 parts of dispersant and 10-15 parts of solvent.

[0006] In any embodiment, the sintering aid is one or more of Y2O3, YF2, Sm2O3 and SmF2.

[0007] In any embodiment, the plasticizer is one or more of PEG200, PEG400, PPG200, PPG400, DBP and DOP.

[0008] In any embodiment, the multifunctional acrylate monomer is one or more of acrylate multifunctional monomer DPHA, acrylate multifunctional monomer PPTTA and ditrimethylolpropane tetraacrylate Di-TMPTA.

[0009] In any embodiment, the low-functional acrylate monomer is one or more of ethoxyethoxyethyl acrylate EOEOEA, lauryl acrylate LA and tetrahydrofuran acrylate THFA.

[0010] In any embodiment, the solvent is one or more of ethanol, toluene and acetone.

[0011] In any embodiment, the dispersant is one or more of BYK111, BYK180, BYK163, Sago9900 and Sago9780.

[0012] In any embodiment, the initiator is one or more of 819, 184 and TPO.

[0013] In addition, the present invention also provides a method for preparing the ceramic slurry for tape casting, comprising the following steps:

[0014] Dissolving a low-functional acrylate monomer in a solvent;

[0015] Continue to dissolve the plasticizer, multifunctional acrylate monomer, initiator and dispersant in the solvent to prepare a premixed solution;

[0016] Evenly mix the aluminum nitride ceramic powder and the sintering aid;

[0017] The mixed aluminum nitride ceramic powder and sintering aid are added into the premixed liquid, and then ball-milled to obtain ceramic slurry.

[0018] In addition, the present invention also provides a method for preparing a green body of aluminum nitride ceramic, comprising: introducing the above-mentioned ceramic slurry for tape casting or the above-mentioned ceramic slurry into the slurry tank of a tape casting machine, and the slurry flows out of the base tape through a doctor blade to form a thin layer;

[0019] After that, the light source of an ultraviolet projector selectively cures and punches the ceramic slurry in-situ to form a single-layer aluminum nitride ceramic green body.

[0020] Compared with the prior art, the beneficial effects of the present invention include: the present invention selects acrylate polyfunctional monomers with large molecular weights and photocuring properties to replace binders such as PVB / PVA used in traditional tape casting; and low molecular weight and low functionality acrylic monomers are added, which can finally endow the aluminum nitride ceramic slurry for tape casting with suitable photocuring properties and ensure its mechanical and thermal properties, so that punching can be realized by photocuring in the tape casting process, and thus the aluminum nitride ceramic slurry can be obtained by avoiding subsequent punching. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a physical diagram of the cured single layer of the ceramic green body prepared in Example 1 of the present invention.

[0022] Figure 2 is an SEM diagram of the ceramic green body prepared in Example 1 of the present invention.

[0023] Figure 3 is the test result of the photocuring performance of the ceramic green bodies of Examples 1-3 and Comparative Examples 1-2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The "scope" disclosed in this application is defined in the form of a lower limit and an upper limit. A given scope is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular scope. The scope defined in this way can include or exclude the end values and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a scope. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, ranges of 60 to 110 and 80 to 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" are fully listed herein, and "0 to 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, the terms "include" and "comprise" mentioned in this application are open-ended and can also be closed-ended. For example, the said "include" and "comprise" can mean that other components not listed can also be included or comprised, or it can only include or comprise the listed components.

[0026] Unless otherwise specified, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0027] This specific embodiment provides an aluminum nitride ceramic slurry for tape casting. Calculated by mass fraction, the raw materials include: 75 - 85 parts of aluminum nitride ceramic powder, 1 - 4 parts of sintering aid, 10 - 15 parts of plasticizer, 3 - 10 parts of multi-functional acrylate monomer, 3 - 10 parts of low-functional acrylate monomer, 1 - 3 parts of initiator, 1 - 2 parts of dispersant, and 10 - 15 parts of solvent; the sintering aid is one or more of Y2O3, YF2, Sm2O3, and SmF2; the plasticizer is one or more of PEG200, PEG400, PPG200, PPG400, DBP, and DOP; the multi-functional acrylate monomer is one or more of acrylate multi-functional monomer DPHA, acrylate multi-functional monomer PPTTA, and ditrimethylolpropane tetraacrylate Di-TMPTA; the low-functional acrylate monomer is one or more of ethoxyethoxyethyl acrylate EOEOEA, lauryl acrylate LA, and tetrahydrofuran acrylate THFA; the solvent is one or more of ethanol, toluene, and acetone; the dispersant is one or more of BYK111, BYK180, BYK163, Sago9900, and Sago9780; the initiator is one or more of 819, 184, and TPO.

[0028] In addition, this specific embodiment also proposes a preparation method of the above-mentioned ceramic slurry for tape casting, including the following steps:

[0029] Dissolve the low-functional acrylate monomer in the solvent;

[0030] Continue to dissolve the plasticizer, multi-functional acrylate monomer, initiator, and dispersant in the solvent to obtain a premixed solution;

[0031] Mix the aluminum nitride ceramic powder and the sintering aid evenly;

[0032] Add the mixed aluminum nitride ceramic powder and sintering aid into the premixed solution, and then ball mill to obtain the ceramic slurry.

[0033] In addition, this specific embodiment also proposes a preparation method of an aluminum nitride ceramic green body, including: introducing the above-mentioned ceramic slurry for tape casting or the above ceramic slurry into the trough of a tape casting machine, and the slurry flows out as a thin layer from the base tape through a doctor blade;

[0034] Then, the ultraviolet projector light source performs in-situ selective curing and punching on the ceramic slurry to form a single-layer aluminum nitride ceramic green body.

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0037] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0038] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0039] The following are examples of the present application. The examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product instructions are used. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially. In the following examples or comparative examples, aluminum nitride ceramic powder and sintering aid powder are dried, ground and sieved.

[0040] In the following examples or comparative examples, the tape casting temperature is 80° C., the tape speed is 50 mm / s, the tape thickness is 200 μm, and a single-layer aluminum nitride thin layer is obtained.

[0041] Example 1

[0042] This embodiment proposes an aluminum nitride ceramic slurry for tape casting. The raw materials, calculated by weight, include: 80 parts of aluminum nitride ceramic powder, 2 parts of sintering aid Y2O3, 12 parts of plasticizer PEG200, 8 parts of acrylate multifunctional monomer DPHA, 8 parts of ethoxyethoxyethyl acrylate EOEOEA, 1 part of initiator 819, 2 parts of dispersant BYK111 and 15 parts of solvent ethanol.

[0043] In addition, this embodiment also provides a method for preparing the ceramic slurry for tape casting, comprising the following steps:

[0044] Dissolving a low-functional acrylate monomer in a solvent;

[0045] Continue to dissolve the plasticizer, multifunctional acrylate monomer, initiator and dispersant in the solvent to prepare a premixed solution;

[0046] Evenly mix the aluminum nitride ceramic powder and the sintering aid;

[0047] The mixed aluminum nitride ceramic powder and sintering aid are added into the premixed liquid, and then transferred to a planetary ball mill for ball milling to obtain a ceramic slurry.

[0048] In addition, this embodiment also provides a method for preparing an aluminum nitride ceramic green body, comprising: introducing the ceramic slurry for tape casting or the ceramic slurry into a material tank of a tape casting machine, and the slurry flows out of a thin layer from a base belt through a scraper;

[0049] Afterwards, the ultraviolet projector light source performs in-situ selective curing and drilling of the ceramic slurry to form a single-layer aluminum nitride ceramic green body.

[0050] The above single-layer green bodies are stacked to prepare complete aluminum nitride ceramic green bodies.

[0051] Combination Figure 1 It can be seen that the required holes are formed on the single-layer aluminum nitride ceramic green body. Figure 2 It can be seen that the obtained aluminum nitride ceramic green body is uniform and compact.

[0052] Example 2

[0053] This embodiment proposes an aluminum nitride ceramic slurry for tape casting. The raw materials, calculated by weight, include: 75 parts of aluminum nitride ceramic powder, 4 parts of sintering aid YF2, 15 parts of plasticizer PPG200, 3 parts of acrylate multifunctional monomer PPTTA, 10 parts of ethoxyethoxyethyl acrylate LA, 2 parts of initiator 184, 1 part of dispersant Sago9900 and 10 parts of solvent toluene.

[0054] In addition, this embodiment also provides a method for preparing the ceramic slurry for tape casting, comprising the following steps:

[0055] Dissolving a low-functional acrylate monomer in a solvent;

[0056] Continue to dissolve the plasticizer, multifunctional acrylate monomer, initiator and dispersant in the solvent to prepare a premixed solution;

[0057] Evenly mix the aluminum nitride ceramic powder and the sintering aid;

[0058] The mixed aluminum nitride ceramic powder and sintering aid are added into the premixed liquid, and then transferred to a planetary ball mill for ball milling to obtain a ceramic slurry.

[0059] In addition, this embodiment also provides a method for preparing an aluminum nitride ceramic green body, comprising: introducing the ceramic slurry for tape casting or the ceramic slurry into a material tank of a tape casting machine, and the slurry flows out of a thin layer from a base belt through a scraper;

[0060] Afterwards, the ultraviolet projector light source performs in-situ selective curing and drilling of the ceramic slurry to form a single-layer aluminum nitride ceramic green body.

[0061] Example 3

[0062] This embodiment proposes an aluminum nitride ceramic slurry for tape casting. The raw materials, calculated by mass, include: 85 parts of aluminum nitride ceramic powder, 1 part of sintering aid Sm2O3, 10 parts of plasticizer DBP, 10 parts of acrylate multifunctional monomer Di-TMPTA, 3 parts of ethoxyethoxyethyl acrylate THFA, 3 parts of initiator TPO, 2 parts of dispersant BYK180 and 12 parts of solvent acetone.

[0063] In addition, this embodiment also provides a method for preparing the ceramic slurry for tape casting, comprising the following steps:

[0064] Dissolving a low-functional acrylate monomer in a solvent;

[0065] Continue to dissolve the plasticizer, multifunctional acrylate monomer, initiator and dispersant in the solvent to prepare a premixed solution;

[0066] Evenly mix the aluminum nitride ceramic powder and the sintering aid;

[0067] The mixed aluminum nitride ceramic powder and sintering aid are added into the premixed liquid, and then transferred to a planetary ball mill for ball milling to obtain a ceramic slurry.

[0068] In addition, this embodiment also provides a method for preparing an aluminum nitride ceramic green body, comprising: introducing the ceramic slurry for tape casting or the ceramic slurry into a material tank of a tape casting machine, and the slurry flows out of a thin layer from a base belt through a scraper;

[0069] Afterwards, the ultraviolet projector light source performs in-situ selective curing and drilling of the ceramic slurry to form a single-layer aluminum nitride ceramic green body.

[0070] Comparative Example 1

[0071] The difference between the tape-cast aluminum nitride ceramic slurry of this comparative example and that of Example 1 is that an equal amount of PVB is used to replace the acrylate multifunctional monomer DPHA, and the other components and amounts are the same as those of Example 1.

[0072] In addition, this comparative example also provides a method for preparing the above-mentioned ceramic slurry for tape casting, comprising the following steps:

[0073] Dissolve the low-functional-group acrylate monomer in a solvent;

[0074] Continue to dissolve the plasticizer, PVB, initiator, and dispersant in the solvent to obtain a premixed solution;

[0075] Mix the aluminum nitride ceramic powder and the sintering aid evenly;

[0076] Add the mixed aluminum nitride ceramic powder and sintering aid to the premixed solution, and then transfer it to a planetary ball mill for ball milling to obtain the ceramic slurry.

[0077] The method for preparing the green body of aluminum nitride ceramic in this comparative example is the same as that in Example 1.

[0078] Comparative Example 2

[0079] The difference between the tape-cast aluminum nitride ceramic slurry in this comparative example and that in Example 1 is only that the acrylate polyfunctional monomer DPHA is not added, and the monomer is replaced with an equal amount of ethanol.

[0080] In addition, this comparative example also provides a method for preparing the above-mentioned ceramic slurry for tape casting, comprising the following steps:

[0081] Dissolve the plasticizer, polyfunctional acrylate monomer, initiator, and dispersant in the solvent to obtain a premixed solution;

[0082] Mix the aluminum nitride ceramic powder and the sintering aid evenly;

[0083] Add the mixed aluminum nitride ceramic powder and sintering aid to the premixed solution, and then transfer it to a planetary ball mill for ball milling to obtain the ceramic slurry.

[0084] The method for preparing the green body of aluminum nitride ceramic in this comparative example is the same as that in Example 1.

[0085] The ceramic slurries of Examples 1-3 and Comparative Examples 1-2 were used to prepare ceramic green bodies under a 405 nm ultraviolet light source with an energy density of 5 mW / cm 2 The photocuring performance is as shown in Figure 3 As can be seen from Figure 3 , for the ceramic green bodies of Examples 1-3 with different thicknesses, the required exposure time is different. The greater the thickness, the longer the required exposure time, indicating that the ceramic green bodies of Examples 1-3 have photocuring performance, while the ceramic green bodies of Comparative Examples 1-2 do not have photocuring performance.

[0086] The ceramic green bodies prepared in Examples 1-3 and Comparative Examples 1-2 were made into ceramics according to the following steps:

[0087] The green ceramic body is degreased and sintered in sequence to obtain the ceramic. The degreasing rate is 0.5 °C / min, the holding temperatures are 280, 380, 450, 600 °C, the holding time is 120 min, the sintering temperature is 1850 °C, and the sintering time is 120 min.

[0088] The ceramics prepared in Examples 1-3 and Comparative Examples 1-2 are tested for their mechanical properties and thermal properties according to Standard GB / T 3962-2017, and the results are shown in Table 1.

[0089] Table 1

[0090] Thermal conductivity W / (m·K) Flexural strength (MPa) Example 1 255 356 Example 2 248 351 Example 3 242 349 Comparative Example 1 219 302 Comparative Example 2 215 305

[0091] As can be seen from Table 1, the thermal conductivity of the green ceramic bodies in Examples 1-3 can be as high as 255 W / (m·K), and the flexural strength can be as high as 356 MPa.

[0092] The present invention provides an aluminum nitride ceramic slurry capable of having a photocuring ability during the tape casting process, and in-situ forming an aluminum nitride ceramic single-layer green body with a pore structure to avoid post-treatment processes such as punching and cutting. This not only significantly reduces the processing time and cost, improves the processing efficiency of the aluminum nitride HTCC ceramic substrate, but also significantly reduces the generation of defects during the post-processing, and improves the performance of the aluminum nitride ceramic substrate.

[0093] The specific embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An aluminum nitride ceramic slurry for tape casting, characterized in that: The raw materials are calculated by weight and include: 75-85 parts of aluminum nitride ceramic powder, 1-4 parts of sintering aids, 10-15 parts of plasticizers, 3-10 parts of multifunctional acrylate monomers, 3-10 parts of low-functional acrylate monomers, 1-3 parts of initiators, 1-2 parts of dispersants and 10-15 parts of solvents.

2. The ceramic slurry for tape casting according to claim 1, characterized in that: The sintering aid is one or more of Y2O3, YF2, Sm2O3 and SmF2.

3. The ceramic slurry for tape casting according to claim 1, characterized in that: The plasticizer is one or more of PEG200, PEG400, PPG200, PPG400, DBP and DOP.

4. The ceramic slurry for tape casting according to claim 1, characterized in that: The multifunctional acrylate monomer is one or more of acrylate multifunctional monomer DPHA, acrylate multifunctional monomer PPTTA and ditrimethylolpropane tetraacrylate Di-TMPTA.

5. The ceramic slurry for tape casting according to claim 1, characterized in that: The low-functional acrylic acid ester monomer is one or more of ethoxyethoxyethyl acrylate EOEOEA, lauryl acrylate LA and tetrahydrofuran acrylate THFA.

6. The ceramic slurry for tape casting according to claim 1, characterized in that: The solvent is one or more of ethanol, toluene and acetone.

7. The ceramic slurry for tape casting according to claim 1, characterized in that: The dispersant is one or more of BYK111, BYK180, BYK163, Sago9900 and Sago9780.

8. The ceramic slurry for tape casting according to claim 1, characterized in that: The initiator is one or more of 819, 184 and TPO.

9. A method for preparing a ceramic slurry for tape casting according to any one of claims 1 to 8, characterized in that: The following steps are involved: Dissolving a low-functional acrylate monomer in a solvent; Continue to dissolve the plasticizer, multifunctional acrylate monomer, initiator and dispersant in the solvent to prepare a premixed solution; The mixed aluminum nitride ceramic powder and sintering aid are added into the premixed liquid, and then ball-milled to obtain ceramic slurry.

10. A method for preparing an aluminum nitride ceramic green body, characterized in that: include: The ceramic slurry for tape casting according to any one of claims 1 to 8 or the ceramic slurry according to claim 9 is introduced into a material tank of a tape casting machine, and the slurry flows out of a thin layer from the base belt through a scraper; Afterwards, the ultraviolet projector light source performs in-situ selective curing and drilling of the ceramic slurry to form a single-layer aluminum nitride ceramic green body.

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