Application of tape-cast fired green porcelain in the preparation of electronic ceramics

Abstract

The invention discloses an application of tape-casting fired green porcelain in the preparation of electronic ceramics. The raw materials of the fired green porcelain include: 30-60 parts of alumina powder, 20-40 parts of white corundum powder, 2-20 parts of acrylic adhesive, 10-40 parts of solvent, alumina powder, and a particle size D of the white corundum powder. 50 The diameters of the raw materials are 30-80 μm respectively, and the amount of acrylic adhesive added accounts for 15%-30% of the total amount of alumina powder and white corundum powder added; the sintering temperature of the raw porcelain when in use is less than or equal to 1650°C; the raw porcelain can be used as a support plate and a covering plate during the sintering process of the raw porcelain product, sandwiching the raw porcelain product in the middle to block and prevent impurities in the sintering furnace from adhering to the surface of the sintered product, while also reducing the warping degree of the sintered product. In addition, it is easy to remove after sintering is completed and will not affect the surface quality of the sintered product.

Description

[0001] This invention is a divisional application of the Chinese invention patent application with the application date of July 29, 2022, application number 2022109031796, and name “A kind of fired raw porcelain and its preparation method and application”. Technical Field

[0002] The present invention relates to the field of electronic ceramics, and in particular to the application of tape-cast fired green porcelain in the preparation of electronic ceramics. Background Art

[0003] Electronic ceramics are typically made by sintering green ceramic sheets (generally obtained by casting alumina slurry) through operations such as punching and metallization slurry printing. The sintering operation is generally performed in a high-temperature furnace. However, due to the volatilization, carbonization, and decomposition of binders and solvents during the sintering process, the furnace environment is relatively dirty, especially in the binder removal area below 500°C. There is a lot of dirt, which often adheres to the product and causes product defects. At the same time, due to the different shrinkage rates of the alumina slurry used in green ceramics and the metallization slurry used in printing, the product will warp during sintering in the furnace, which has a certain negative impact on product quality. Summary of the Invention

[0004] The purpose of the present invention is to overcome one or more deficiencies in the prior art and provide a new tape-cast fired green porcelain for use in the preparation of electronic ceramics. The fired green porcelain can serve as a support plate and a cover plate during the sintering process of the product green porcelain, sandwiching the product green porcelain in the middle to block and prevent impurities in the sintering furnace from adhering to the surface of the sintered product, while also reducing the degree of warping of the sintered product. In addition, it is easy to remove after sintering is completed and will not affect the surface quality of the sintered product.

[0005] To achieve the above object, the present invention adopts a technical solution: an application of tape-cast fired green porcelain in the preparation of electronic ceramics, characterized in that the raw materials of the fired green porcelain include, by weight, 30-60 parts of alumina powder, 20-40 parts of white corundum powder, 2-20 parts of acrylic adhesive, and 10-40 parts of solvent;

[0006] Wherein, the particle size D of the aluminum oxide powder is 50 The particle size D of the white corundum powder is 30-80 μm. 50 30-80μm;

[0007] In terms of percentage by mass, the amount of the acrylic binder added to the raw materials for firing green porcelain is 15%-30% of the total amount of the alumina powder and the white corundum powder added;

[0008] The sintering temperature of the raw porcelain is less than or equal to 1650° C. when in use.

[0009] Another technical solution provided by the present invention is a raw porcelain for firing, wherein the raw materials for firing the raw porcelain include, by weight:

[0010]

[0011] Wherein, the particle size D of the aluminum oxide powder is 50 The particle size D of the white corundum powder is 30-80 μm. 50 30-80μm;

[0012] Calculated by mass percentage, in the raw materials for firing green porcelain, the added amount of the acrylic adhesive accounts for 15%-30% of the total added amount of the aluminum oxide powder and the white corundum powder.

[0013] According to some preferred aspects of the present invention, the raw materials for firing green porcelain include, by weight:

[0014]

[0015] According to some preferred aspects of the present invention, the mass ratio of the aluminum oxide powder to the white corundum powder is 1:0.1-0.8.

[0016] According to some preferred aspects of the present invention, the particle size D of the white corundum powder is 50 Smaller than the particle size D of the alumina powder 50 .

[0017] According to some preferred aspects of the present invention, the acrylic adhesive has a weight average molecular weight of 400,000-600,000 and a glass transition temperature of -10 to 30°C.

[0018] More preferably, the acrylic adhesive has a weight average molecular weight of 450,000-550,000 and a glass transition temperature of 0-20°C.

[0019] According to a specific aspect of the present invention, the acrylic adhesive is KFA-440 produced by Huying Chemical.

[0020] In some embodiments of the present invention, the solvent is toluene.

[0021] Another technical solution provided by the present invention is a method for preparing the above-mentioned raw porcelain, the method comprising:

[0022] Weigh all raw materials according to the formula, add alumina powder, white corundum powder and solvent into the ball mill, and perform ball milling once;

[0023] Then, an acrylic adhesive was added and ball milling was performed twice;

[0024] Degassing and casting.

[0025] According to some preferred and specific aspects of the present invention, the milling time of the first ball milling and the second ball milling are controlled to be 2-4 hours respectively.

[0026] According to some preferred and specific aspects of the present invention, in the casting machine used for the casting, the temperatures of the four temperature zones are: 55-75°C, 65-85°C, 75-95°C, and 85-105°C.

[0027] Another technical solution provided by the present invention is an application of the above-mentioned raw ceramic in the preparation of electronic ceramics, the application comprising:

[0028] Placing the green porcelain product to be fired on the first supporting green porcelain, and covering the upper surface of the green porcelain product to be fired with the second supporting green porcelain to form a stacked assembly to be fired, and then placing the assembly to be fired in a sintering furnace for sintering;

[0029] After sintering is completed, the first fired green porcelain becomes a first fired product, the to-be-fired green porcelain becomes a ceramic product, and the second fired green porcelain becomes a second fired product. The first fired product, the ceramic product, and the second fired product are stacked in sequence, and the first fired product and the second fired product are peeled off respectively to obtain the ceramic product, which is then processed into an electronic ceramic.

[0030] The first fired green porcelain and the second fired green porcelain are respectively the fired green porcelains described above.

[0031] According to the present invention, in the application, the sintering temperature is less than 1800°C.

[0032] Furthermore, the sintering temperature is less than or equal to 1650°C.

[0033] In some embodiments of the present invention, the green porcelain product to be fired is made of alumina slurry, and the alumina slurry can adopt the formula components commonly used in the prior art.

[0034] Preferably, the alumina slurry adopts the following formula components:

[0035] Calculated by mass percentage, the raw materials of the alumina slurry include: 45%-60% powdered alumina, 2%-8% auxiliary powder, 0.5%-5% molybdenum powder solution, 8%-20% acrylic adhesive, 0.05%-3% plasticizer, and 15%-40% first organic solvent.

[0036] Furthermore, in terms of mass percentage, in the alumina slurry, powdered alumina accounts for 47%-58%, auxiliary powder accounts for 2%-7%, molybdenum powder solution accounts for 0.8%-3.5%, acrylic adhesive accounts for 10%-18%, plasticizer accounts for 0.1%-1.5%, and the first organic solvent accounts for 15%-38%.

[0037] The auxiliary powder in the present invention does not contain metallic molybdenum powder.

[0038] According to some preferred aspects of the present invention, the auxiliary powder includes silicon dioxide, talc and chromium oxide.

[0039] According to some preferred aspects of the present invention, the mass ratio of the silicon dioxide, the talc powder and the chromium oxide is 4-5.5:1.5-3.5:1.

[0040] In some embodiments of the present invention, the auxiliary powder consists of silicon dioxide, talc and chromium oxide.

[0041] According to some preferred aspects of the present invention, the molybdenum powder solution is obtained by dispersing metallic molybdenum powder in a second organic solvent with a mass fraction of 20-40%. The second organic solvent may be isopropyl alcohol.

[0042] According to some preferred aspects of the present invention, the plasticizer may be dibutyl phthalate.

[0043] According to some preferred aspects of the present invention, the first organic solvent is an organic solvent that is incompatible with or insoluble in water. According to a specific and preferred aspect of the present invention, the first organic solvent may be toluene.

[0044] The preparation method of the alumina slurry comprises the following steps:

[0045] (1) adding powdered aluminum oxide, auxiliary powder, molybdenum powder solution and a first organic solvent into a ball mill respectively, and performing a first ball milling;

[0046] (2) adding a portion of the acrylic binder to the ball mill for a second ball milling, and monitoring the particle size of the particles in the slurry during the ball milling process;

[0047] (3) when the particle size reaches a preset value, the second ball milling is stopped, the remaining acrylic binder and plasticizer are added, and the third ball milling is performed to obtain an alumina slurry;

[0048] In particular, in terms of mass percentage, the acrylic binder in step (2) accounts for 0.5%-5% of the total amount of acrylic binders added, and the acrylic binder in step (2) accounts for 0.05%-2% of the amount of powdered alumina added, and the time used for the second ball milling accounts for more than 75% of the total ball milling time of the first ball milling, the second ball milling, and the third ball milling. In practice, it was found that only a small amount of appropriate acrylic binder was added to participate in the main ball milling process of preparing alumina slurry, and most of the acrylic binder and all of the plasticizer were added last. This method not only successfully achieved uniform dispersion of the various components in the alumina slurry in a relatively short time, so that each particle, including the alumina particles, was free from agglomeration or soft agglomeration, greatly saving time and cost, and being conducive to large-scale production and application, but also this ball milling method enabled the particles to obtain a suitable and narrow particle size distribution in a relatively short time, so that after the green ceramic sheet made of the alumina slurry was sintered into an electronic ceramic, the electronic ceramic could have a stable and controllable shrinkage rate, thereby ensuring stable product quality.

[0049] In addition, during a large number of experimental practices, alumina slurry is very prone to gelation in the initial mixing stage or during the ball milling process, which makes ball milling difficult. Once formed, it is difficult to continue to use it as a slurry for the casting system, making it impossible to prepare raw porcelain, resulting in a significant increase in production costs. After combining experiments with production practices, the inventors analyzed that the gelation phenomenon may be caused by the presence of water in the system. However, in practice, even if the powdered raw materials such as powdered alumina are subjected to a certain drying treatment, gelation still occurs to varying degrees in different batches. Later, the inventors unexpectedly discovered that when the organic solvent-based casting system uses other types of adhesives such as PVB (polyvinyl butyral), the occurrence of gelation is basically avoided when the powdered raw materials such as powdered alumina are subjected to a certain drying treatment. After comparison, it is believed that the present invention may use an acrylic adhesive, the functional group carboxyl group it contains should be able to form multiple hydrogen bonds with water, resulting in the system gelation phenomenon being able to occur and be more obvious even when the moisture content is very low. However, if the moisture needs to be completely removed, the dehydration operation will be time-consuming and energy-consuming, which is not conducive to reducing costs and improving production efficiency. After continuous experiments and summaries, according to some preferred aspects of the present invention, in step (1), the water content of the alumina powder and the auxiliary agent powder is controlled to be lower than 0.75% before being added to the ball mill, which can basically control the occurrence of gelation, and the dehydration time and energy consumption are within a reasonable range.

[0050] According to some preferred aspects of the present invention, the portion of acrylic adhesive in step (2) accounts for 1%-4% of the total amount of acrylic adhesive added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of acrylic adhesive in step (2) accounts for 1%-2% of the total amount of acrylic adhesive added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of acrylic adhesive in step (2) accounts for 2%-3% of the total amount of acrylic adhesive added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of acrylic adhesive in step (2) accounts for 3%-4% of the total amount of acrylic adhesive added, calculated as a percentage by mass.

[0051] According to some preferred aspects of the present invention, the portion of the acrylic binder in step (2) accounts for 0.1%-1.5% of the amount of the powdered aluminum oxide added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of the acrylic binder in step (2) accounts for 0.1%-0.5% of the amount of the powdered aluminum oxide added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of the acrylic binder in step (2) accounts for 0.5%-1% of the amount of the powdered aluminum oxide added, calculated as a percentage by mass. In some embodiments of the present invention, the portion of the acrylic binder in step (2) accounts for 1%-1.5% of the amount of the powdered aluminum oxide added, calculated as a percentage by mass.

[0052] According to the present invention, the preset value is: D 50 1.9-2.5μm.

[0053] According to some preferred aspects of the present invention, the time used for the first ball milling accounts for 1%-5% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling.

[0054] In some embodiments of the present invention, the time used for the first ball milling accounts for 2%-4% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling.

[0055] Furthermore, the time used for the second ball milling accounts for more than 80% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling.

[0056] In some embodiments of the present invention, the method for preparing the green porcelain product to be fired comprises: mixing the alumina slurry uniformly and then performing vacuum degassing to remove bubbles in the slurry, then entering the slurry into a tape casting machine to cast green porcelain, cutting it into sheets according to a certain size to obtain green porcelain pieces, and then printing electronic paste on the green porcelain pieces to produce the green porcelain product to be fired;

[0057] The four temperature zones of the casting machine are: 75±10℃, 95±10℃, 120±10℃, and 130±10℃.

[0058] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0059] Based on the problems of poor surface performance and easy warping in the sintering process of existing green porcelain pieces, the present invention innovatively provides a new type of supporting green porcelain. The supporting green porcelain can serve as a support plate and a covering plate during the sintering process of the product green porcelain, sandwiching the product green porcelain in the middle to block and prevent impurities in the sintering furnace from adhering to the surface of the sintered product, while also reducing the degree of warping of the sintered product. In addition, it is easy to remove after sintering is completed and will not affect the surface quality of the sintered product.

[0060] Specifically, in the present invention, the fired green porcelain is combined with alumina powder, white corundum powder and acrylic adhesive. Since white corundum powder is made by cooling industrial alumina powder after smelting at a high temperature of more than 2000°C, and the sintering temperature of alumina is about 1800°C without adding a sintering aid, and the existing conventional alumina slurry basically adds a sintering aid such as silicon dioxide, etc., which reduces the sintering temperature of alumina, under normal circumstances, the maximum sintering temperature of the sintering furnace is generally 1650°C. Under such conditions, once the fired green porcelain of the present invention and the green porcelain of the product to be fired are co-sintered according to the superposition method of the present invention, the middle The raw porcelain of the product to be fired can be formed normally, and the raw porcelain of the present invention has a loose overall structure after firing due to the presence of white corundum powder, and in the presence of alumina powder, the whole remains roughly intact. When an appropriate amount of binder is selected, neither white corundum chips will appear on the ceramic product, nor will the raw porcelain of the product be bonded to the ceramic product. It can be easily peeled off without affecting the quality of the ceramic product. At the same time, the raw porcelain of the product serves as a support plate and a covering plate during the sintering process of the raw porcelain of the product, sandwiching the raw porcelain of the product in the middle to block and prevent impurities in the sintering furnace from adhering to the surface of the ceramic product obtained by sintering.

[0061] Furthermore, in the present invention, in a high-temperature sintering furnace, the product removes organic matter such as binders at temperatures below 500°C, decarbonizes organic matter at temperatures between 500-1100°C, and begins sintering alumina above 1100°C. After debinding, gaps appear between the alumina particles, and organic matter such as carbon in the product is slowly removed through the gaps between the alumina particles of the raw porcelain and the gaps between the white corundum particles. At around 1600°C, the product begins to sinter rapidly, and the alumina particles slowly fuse to fill the gaps, resulting in successful sintering. Since the raw porcelain does not have a sintering aid, the required sintering temperature is relatively high, so a relatively large gap is always maintained during the product firing process, which facilitates the removal of organic matter from the product. Therefore, the setting of the raw porcelain of the present invention does not affect the operation of removing the binder during the sintering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 Schematic diagram of the superposition of the assembly to be fired in an embodiment of the present invention;

[0063] Among them, 1. The first firing is for raw porcelain; 2. The raw porcelain to be fired is for products; 3. The second firing is for raw porcelain. DETAILED DESCRIPTION

[0064] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0065] Unless otherwise specified in the following examples, all raw materials were purchased from commercial sources or prepared by conventional methods in the art.

[0066] Alumina powder was purchased from AMB, brand, and D was measured when used. 50 65±5μm;

[0067] White corundum powder can be homemade or commercially available. In the following examples, commercially available white corundum powder F180 (GB2477-83) was used. 50 80±5μm;

[0068] D 50 Measured by Malvern 3000 laser particle size analyzer;

[0069] The acrylic adhesive is KFA-440 from Huying Chemical;

[0070] Metallic molybdenum powder, silicon dioxide, talc, and chromium oxide are all commercially available, with a Fisher particle size between 1 and 2.3 μm;

[0071] Dibutyl phthalate was commercially available with a purity of 99%;

[0072] The ball mill is a commercially available 300L ball mill with a ceramic lining or a nylon lining. The operating parameters are: a rotation speed of 40±5rpm, a grinding ball of alumina with a particle size of about 30mm, and a material-to-ball ratio of 1:1.

[0073] Example 1

[0074] This example provides a fired green porcelain and a preparation method thereof. The raw materials of the fired green porcelain include, by weight:

[0075]

[0076]

[0077] The preparation method of the fired green porcelain comprises:

[0078] Weigh all raw materials according to the formula, add alumina powder, white corundum powder and toluene into a ball mill, and perform ball milling for 3 hours;

[0079] Then, an acrylic adhesive was added and ball milling was performed for a second time for 3 hours;

[0080] After degassing, the casting is carried out. In the casting machine used, the temperatures of the four temperature zones are: 65℃±5℃, 75℃±5℃, 85℃±5℃, 95℃±5℃, and the green porcelain with a thickness of 0.6mm is cast and cut into 230mm*130mm (Y*X) green porcelain sheets for firing.

[0081] Example 2

[0082] This example provides a fired green porcelain and a preparation method thereof. The raw materials of the fired green porcelain include, by weight:

[0083] 55 parts of alumina powder

[0084] 20 parts of white corundum powder

[0085] 15 parts acrylic adhesive

[0086] 10 parts of toluene;

[0087] The preparation method of the fired green porcelain comprises:

[0088] Weigh all raw materials according to the formula, add alumina powder, white corundum powder and toluene into a ball mill, and perform ball milling for 3 hours;

[0089] Then, an acrylic adhesive was added and ball milling was performed for a second time for 3 hours;

[0090] After degassing, the casting is carried out. In the casting machine used, the temperatures of the four temperature zones are: 65℃±5℃, 75℃±5℃, 85℃±5℃, 95℃±5℃, and the green porcelain with a thickness of 0.6mm is cast and cut into 230mm*130mm (Y*X) green porcelain sheets for firing.

[0091] Example 3

[0092] This example provides a fired green porcelain and a preparation method thereof. The raw materials of the fired green porcelain include, by weight:

[0093]

[0094] The preparation method of the fired green porcelain comprises:

[0095] Weigh all raw materials according to the formula, add alumina powder, white corundum powder and toluene into a ball mill, and perform ball milling for 3 hours;

[0096] Then, an acrylic adhesive was added and ball milling was performed for a second time for 3 hours;

[0097] After degassing, the casting is carried out. In the casting machine used, the temperatures of the four temperature zones are: 65℃±5℃, 75℃±5℃, 85℃±5℃, 95℃±5℃, and the green porcelain with a thickness of 0.6mm is cast and cut into 230mm*130mm (Y*X) green porcelain sheets for firing.

[0098] Comparative Example 1

[0099] The same as Example 1, except that the white corundum powder is commercially available 400#, D 50 :25±5μm.

[0100] Comparative Example 2

[0101] The method is basically the same as Example 1, with the only difference being that, in terms of mass percentage, the amount of the acrylic binder added to the raw materials for firing green porcelain is 10% of the amount of the alumina powder + white corundum added.

[0102] Comparative Example 3

[0103] The method is basically the same as Example 1, with the only difference being that, in terms of mass percentage, the amount of the acrylic binder added to the raw materials for firing the green porcelain is 40% of the amount of the alumina powder + white corundum added.

[0104] Comparative Example 4

[0105] The method is basically the same as Example 1, with the only difference being that, in terms of mass percentage, the amount of the acrylic binder added to the raw materials for firing green porcelain is 50% of the amount of the alumina powder + white corundum added.

[0106] Application Example 1

[0107] The fired green ceramic obtained in Example 1 is used to prepare electronic ceramics, and the specific steps include:

[0108] Place the green porcelain product to be fired on the first green porcelain 1, and cover the upper surface of the green porcelain product to be fired 2 with the second green porcelain 3 to form a stacked assembly to be fired (such as Figure 1As shown), the assembly to be fired is then placed in a sintering furnace for sintering (debonding temperature 500°C, 3.5 hours; 500-1100°C, 3.5 hours; 1100-1600°C, 5.5 hours; heating rate: 5°C per minute); after the sintering is completed, the first fired green porcelain 1 becomes the first fired product, the green porcelain 2 to be fired becomes the ceramic product, and the second fired green porcelain 3 becomes the second fired product. The first fired product, the ceramic product, and the second fired product are stacked in sequence, and the first fired product and the second fired product are peeled off respectively to obtain a ceramic product, which is then processed into an electronic ceramic;

[0109] The first fired green porcelain 1 and the second fired green porcelain 3 are the fired green porcelains obtained in Example 1;

[0110] The green porcelain product 2 to be fired is obtained by the following method:

[0111] (1) Preparation of alumina slurry

[0112] The alumina slurry comprises the following components: powdered alumina accounts for 47%, auxiliary powder accounts for 4%, molybdenum powder solution accounts for 3%, acrylic adhesive accounts for 12%, plasticizer accounts for 0.3%, and toluene accounts for 33.7%; wherein the auxiliary powder is composed of silicon dioxide, talc powder and chromium oxide, and the mass ratio of silicon dioxide, talc powder and chromium oxide is 5:3:1; the molybdenum powder solution is obtained by dispersing metal molybdenum powder in isopropyl alcohol, and its mass fraction is 30%; the powdered alumina is purchased from AMB, brand, and the D 50 60-70μm;

[0113] The alumina powder and the auxiliary agent powder weighed in proportion are dried separately in a drying room at a temperature of 80±10°C until the moisture content is reduced to 0.75% and set aside;

[0114] The preparation method of the alumina slurry comprises the following steps:

[0115] Step 1: Put the dried powdered alumina into the ball mill;

[0116] Step 2: Put the dried additive powder into the ball mill;

[0117] Step 3: Pour isopropyl alcohol into a stainless steel barrel, then put metallic molybdenum powder into the stainless steel barrel containing isopropyl alcohol and stir evenly to obtain a molybdenum powder solution, and finally put the molybdenum powder solution into a ball mill;

[0118] Step 4: Add toluene into the ball mill;

[0119] Step 5: Cover the ball mill and perform the first ball milling. After running for 2 hours, stop and open the cover. Put some acrylic adhesive into the ball mill. Then cover the cover and start the ball mill to perform the second ball milling. During the ball milling process, the particle size D 50 Monitoring is carried out; among them, some acrylic adhesives account for 1.5% of the total added amount of acrylic adhesives;

[0120] Step 6: When the particle size reaches the preset value D 50 When the particle size is 1.9-2.5 μm, the second ball milling time is about 50 hours;

[0121] At the same time, when the particle size reaches the required level, the ball mill lid is opened and the remaining acrylic binder is added to the ball mill. Dibutyl phthalate is then added to the ball mill and the mill is run for 5 hours to obtain an alumina slurry. No gelation occurs during the above preparation process.

[0122] (2) Preparation of green porcelain to be fired

[0123] The alumina slurry prepared in step (1) is mixed evenly and then vacuum degassed to remove bubbles in the slurry before entering a tape casting machine to cast green porcelain, which is then cut into sheets of green porcelain to be fired according to a certain size;

[0124] The four temperature zones of the casting machine are: 75±10℃, 95±10℃, 120±10℃, and 130±10℃;

[0125] A green porcelain sheet with a thickness of 0.6 mm is cast and cut into green porcelain sheets of 60 mm*20 mm (Y*X).

[0126] X direction: refers to the casting direction; Y direction: refers to the direction perpendicular to the casting direction;

[0127] The green porcelain pieces are made into green porcelain products to be fired by the following method:

[0128] The self-made electronic printing paste with a thickness of 18-22μm was printed on the green porcelain sheet, and the green porcelain sheet without printing paste was sintered in the furnace at the same time for comparison.

[0129] Homemade printed electronic paste: It is a mixture of tungsten powder (as the conductive phase), aluminum oxide (as the binding phase), and a binder;

[0130] Tungsten powder: 50 parts FSSS particle size 1-5 microns

[0131] Alumina: 1 part FSSS particle size 0.1-2 microns

[0132] Niobium oxide: 1 part

[0133] Acetone: 38 parts

[0134] Binder: 10 parts (made from nitrocellulose and dibutyl phthalate in a ratio of 1:2);

[0135] Tungsten powder and alumina powder sintering aid are added with acetone and placed in a 300L ceramic inner wall or nylon inner wall. Grind for 24 hours at a speed of 50±10rpm.

[0136] 6 parts of binder were added and grinding was continued for 2 hours.

[0137] After discharging, add the material to the stirring tank, remove the acetone under vacuum, add 4 parts of binder and continue stirring for 0.5 hours;

[0138] The product will be shipped after the viscosity meets the requirements.

[0139] Application Example 2

[0140] The method is basically the same as that of Example 1, with the only difference being that the raw porcelain used in Example 2 is replaced by the raw porcelain used in Example 2.

[0141] Application Example 3

[0142] The method is basically the same as that of Example 1, with the only difference being that the raw porcelain used in Example 3 is replaced by the raw porcelain used in Example 3.

[0143] Comparative Application Example 1

[0144] The method is basically the same as Example 1, with the only difference being that the raw porcelain used in Comparative Example 1 is replaced by the raw porcelain used in Comparative Example 1.

[0145] Application Comparative Example 2

[0146] The method is basically the same as Example 1, with the only difference being that the raw porcelain used in Comparative Example 2 is replaced by the raw porcelain used in Comparative Example 2.

[0147] Application Comparative Example 3

[0148] The method is basically the same as Example 1, with the only difference being that the raw porcelain used in Comparative Example 3 is replaced by the raw porcelain used in Comparative Example 3.

[0149] Comparative Application Example 4

[0150] The method is basically the same as Example 1, with the only difference being that the raw porcelain used in Comparative Example 4 is replaced by the raw porcelain used in Comparative Example 4.

[0151] Performance Testing

[0152] 1. During and after the porcelain-forming process, the states of the first-fired product (obtained after the first-fired raw porcelain is fired), the second-fired product (obtained after the second-fired raw porcelain is fired), and the ceramic product (obtained after the unfired product is fired after the raw porcelain is fired) are observed, as well as their respective states relative to each other. Specific results are shown in Table 1.

[0153] Table 1

[0154]

[0155]

[0156] 2. Measure the warpage of ceramic products after forming. The specific test method is as follows:

[0157] Use a vernier caliper to measure the thickness of the ceramic sheet (including warpage). Use the vernier caliper to completely clamp the middle of the ceramic sheet and measure the thickness. Subtract the thickness of the ceramic sheet without printed electronic paste from the thickness of the ceramic sheet with printed electronic paste to get the warpage of the ceramic sheet.

[0158] The specific results are shown in Table 2.

[0159] Table 2

[0160]

[0161] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0162] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. Application of tape-cast fired green porcelain in the preparation of electronic ceramics, characterized in that: The raw materials for firing green porcelain include, by weight: 30-60 parts of alumina powder, 20-40 parts of white corundum powder, 2-20 parts of acrylic adhesive, and 10-40 parts of solvent; Wherein, the particle size D of the aluminum oxide powder is 50 The particle size D of the white corundum powder is 30-80 μm. 50 The particle size is 30-80 μm, and the mass ratio of the aluminum oxide powder to the white corundum powder is 1:0.1-0.8; In terms of mass percentage, the amount of the acrylic binder added to the raw material for firing green porcelain accounts for 15%-30% of the total amount of the aluminum oxide powder and the white corundum powder added; The sintering temperature of the raw porcelain is less than or equal to 1650° C. when in use.

2. The use according to claim 1, characterized in that: The raw materials for firing green porcelain include, by weight: 50-60 parts of alumina powder, 20-40 parts of white corundum powder, 15-20 parts of acrylic adhesive, and 10-40 parts of solvent; Or, in parts by weight, the raw materials for firing green porcelain include: 40-55 parts of alumina powder, 20-30 parts of white corundum powder, 15-20 parts of acrylic adhesive, and 10-20 parts of solvent.

3. The use according to claim 1, characterized in that: The particle size D of the white corundum powder 50 Smaller than the particle size D of the alumina powder 50 ; The solvent is toluene.

4. The use according to claim 1, characterized in that: The preparation method of the fired green porcelain comprises: Weigh the raw materials according to the formula, add the alumina powder, white corundum powder and solvent into the ball mill, and perform ball milling once; Then, an acrylic adhesive was added and ball milling was performed twice; Casting after degassing; The ball milling time of the first ball milling and the second ball milling is controlled to be 2-4 hours respectively; in the casting machine used for the casting, the temperatures of the four temperature zones are: 55-75°C, 65-85°C, 75-95°C, and 85-105°C respectively.

5. The use according to claim 1, characterized in that: The applications include: Placing the green porcelain of the product to be fired on the first green porcelain, and covering the upper surface of the green porcelain of the product to be fired with the second green porcelain, to form a stacked assembly to be fired, and then placing the assembly to be fired in a sintering furnace for sintering; After sintering is completed, the first-fired raw porcelain becomes the first fired product, the raw porcelain of the product to be fired becomes the ceramic product, and the second-fired raw porcelain becomes the second fired product. The first fired product, the ceramic product and the second fired product are stacked in sequence, and the first fired product and the second fired product are peeled off respectively to obtain the ceramic product, and the ceramic product is processed into electronic ceramics.

6. The use according to claim 5, characterized in that: The green porcelain product to be fired is made of alumina slurry. Calculated by mass percentage, the raw materials of the alumina slurry include: 45%-60% powdered alumina, 2%-8% auxiliary powder, 0.5%-5% molybdenum powder solution, 8%-20% acrylic adhesive, 0.05%-3% plasticizer, and 15%-40% first organic solvent.

7. The use according to claim 6, characterized in that: In terms of mass percentage, in the alumina slurry, powdered alumina accounts for 47%-58%, auxiliary powder accounts for 2%-7%, molybdenum powder solution accounts for 0.8%-3.5%, acrylic adhesive accounts for 10%-18%, plasticizer accounts for 0.1%-1.5%, and the first organic solvent accounts for 15%-38%.

8. The use according to claim 6 or 7, characterized in that: The auxiliary powder comprises silicon dioxide, talcum powder and chromium oxide, and the mass ratio of the silicon dioxide, the talcum powder and the chromium oxide is 4-5.5:1.5-3.5:1; The first organic solvent is an organic solvent that is incompatible with or insoluble in water; The molybdenum powder solution is obtained by dispersing metallic molybdenum powder in a second organic solvent, with a mass fraction of 20-40%, and the second organic solvent is isopropanol.

9. The use according to any one of claims 1 to 4, 6 to 7, characterized in that: The acrylic adhesive has a weight average molecular weight of 400,000 to 600,000 and a glass transition temperature of -10 to 30°C.

10. The use according to claim 9, characterized in that: The acrylic adhesive has a weight average molecular weight of 450,000-550,000 and a glass transition temperature of 0-20°C.

11. The use according to claim 10, characterized in that: The acrylic adhesive is KFA-440 from Huye Chemical.

12. The use according to claim 6 or 7, characterized in that: The preparation method of the alumina slurry comprises the following steps: (1) adding powdered aluminum oxide, additive powder, molybdenum powder solution and a first organic solvent into a ball mill respectively to perform a first ball milling; (2) adding a portion of the acrylic binder to the ball mill for a second ball milling, and monitoring the particle size of the particles in the slurry during the ball milling process; (3) when it is monitored that the particle size reaches a preset value, the second ball milling is stopped, the remaining acrylic binder and plasticizer are added, and the third ball milling is performed to obtain an alumina slurry; Wherein, in terms of mass percentage, the portion of acrylic adhesive in step (2) accounts for 0.5%-5% of the total amount of acrylic adhesive added, and the portion of acrylic adhesive in step (2) accounts for 0.05%-2% of the amount of powdered alumina added, and the time used for the second ball milling accounts for more than 75% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling.

13. The use according to claim 12, characterized in that: In step (1), the water content of the alumina powder and the auxiliary powder before being added to the ball mill is controlled to be lower than 0.75% respectively; and / or, in terms of mass percentage, the part of the acrylic adhesive in step (2) accounts for 1%-4% of the total amount of acrylic adhesive added; and / or, in terms of mass percentage, the part of the acrylic adhesive in step (2) accounts for 0.1%-1.5% of the amount of the powdered alumina added; and / or, the time used for the first ball milling accounts for 1%-5% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling; and / or, the time used for the second ball milling accounts for more than 80% of the total ball milling time of the first ball milling, the second ball milling and the third ball milling.

14. The use according to claim 6 or 7, characterized in that: The method for preparing the green porcelain to be fired comprises: mixing the alumina slurry uniformly and then performing vacuum degassing, removing bubbles in the slurry and then entering the slurry into a tape casting machine to cast green porcelain, cutting the green porcelain pieces according to a certain size, and then printing electronic slurry for printing on the green porcelain pieces to prepare the green porcelain to be fired; The four temperature zones of the casting machine are: 75±10℃, 95±10℃, 120±10℃, and 130±10℃.

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