Aluminum nitride ceramic material for HTCC and method for manufacturing the same

Abstract

The application discloses a kind of aluminium nitride ceramic materials for HTCC and preparation method thereof, belong to aluminium nitride ceramic materials technical field for HTCC, including the following mass ratio of ingredients: modified aluminium nitride powder 45-55, sand mill sintering aid 2-3, solvent 30-40, dispersing agent 1.5-5, binder 0.5-1 and plasticizer 7-10, aluminium nitride ceramic material is prepared by above ingredients.The HTCC aluminium nitride ceramic material prepared by the modified alumina powder and other ingredients according to the proportion, realizes high thermal conductivity, high bending strength aluminium nitride ceramic, solves the problem of low thermal conductivity of existing aluminium nitride ceramic, the thermal conductivity coefficient reaches more than 200 W / (m•K), the bending strength is more than 400Mpa, can meet the use requirement of device.

Description

Technical Field

[0001] This invention belongs to the technical field of aluminum nitride ceramic materials for HTCC, specifically relating to an aluminum nitride ceramic material for HTCC, and also to a method for preparing the aluminum nitride ceramic material for HTCC. Background Technology

[0002] With the rapid development of microelectronics technology, devices are required to evolve towards higher capacity, higher density, higher speed, and higher power output. Increasingly complex devices place increasingly higher demands on the thermal conductivity and strength of packaging materials. Aluminum nitride is a novel ceramic material with excellent comprehensive properties, possessing high thermal conductivity, relatively low dielectric constant and dielectric loss, and a coefficient of thermal expansion (approximately 3.5 × 10⁻⁶) that matches that of chip materials such as silicon and gallium arsenide. -6 K -1 ~4.8×10 -6 K -1 With its excellent properties such as non-toxicity and insulation, it is considered the preferred material for packaging next-generation electronic devices and has been widely used in electronics, automotive, aerospace and other fields.

[0003] Aluminum nitride ceramics are sintered from aluminum nitride powder. The main factors affecting the performance of aluminum nitride ceramics include the properties of the aluminum nitride powder, the type of sintering aid, and the sintering process. Among these, the properties of the aluminum nitride powder are crucial in determining the preparation process and quality of aluminum nitride ceramics. Theoretically, aluminum nitride has a thermal conductivity of 320 W / (m·K). However, aluminum nitride powder is prone to hydrolysis in air, and oxygen impurities diffuse into the aluminum nitride lattice during sintering, resulting in a decrease in the thermal conductivity of aluminum nitride ceramics. The thermal conductivity of actually produced aluminum nitride ceramics is generally below 180 W / (m·K). The flexural strength of aluminum nitride ceramics is only between 300 and 390 MPa, which cannot meet the needs of the microelectronics packaging industry, limiting the application range of aluminum nitride ceramics. Currently, developing new methods to prepare aluminum nitride ceramics with high thermal conductivity and high flexural strength is of great significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an aluminum nitride ceramic material for HTCC and its preparation method, so as to obtain aluminum nitride ceramic with high thermal conductivity and high bending strength, and solve the problem of low thermal conductivity of existing aluminum nitride ceramics.

[0005] The technical solution adopted in this invention is as follows: an aluminum nitride ceramic material for HTCC, comprising the following ingredients in the following mass ratio:

[0006] Aluminum nitride ceramic material is prepared from the following ingredients: 45-55 parts modified aluminum nitride powder, 2-3 parts sand milling and sintering aid, 30-40 parts solvent, 1.5-5 parts dispersant, 1-3 parts binder, and 5-7 parts plasticizer.

[0007] Furthermore, the above-mentioned method for preparing aluminum nitride ceramic material for HTCC includes the following steps:

[0008] Step 1, Modification and Milling: The aluminum nitride powder is surface modified and refined by milling with sintering aids;

[0009] Step 2, primary and secondary ball milling: The modified aluminum nitride powder, the sintering aid refined by sand milling, the solvent and the dispersant are added together to the ball mill for primary ball milling. After the primary ball milling, the binder and plasticizer are added for secondary ball milling.

[0010] Step 3, Degassing: After secondary ball milling, the slurry after ball milling is degassed using a vacuum degassing machine to obtain ceramic slurry;

[0011] Step 4: Casting and Shaping: The ceramic slurry is cast and dried to obtain a ceramic green body;

[0012] Step 5: Slicing: Cut the ceramic green body into slices;

[0013] Step 6, Debinding: Place the blank into the debinding furnace for debinding;

[0014] Step 7, Sintering: High thermal conductivity and high bending strength aluminum nitride ceramics are obtained by high-temperature sintering in a vacuum furnace.

[0015] Furthermore, the above surface modification treatment formula is as follows: the mass ratio of aluminum nitride powder, citric acid, silane coupling and anhydrous ethanol is 45-55:2-10:5-15:30-40.

[0016] Further, the above surface modification treatment method is as follows: aluminum nitride powder, citric acid and silane coupling agent are added to a set amount of anhydrous ethanol to obtain an aluminum nitride mixed slurry. The aluminum nitride mixed slurry is dispersed evenly using a ball mill at a speed of 300-600 r / min and a dispersion time of 8-12 h. The uniform aluminum nitride mixed slurry after ball milling is placed in an oven for drying at a temperature of 80-100℃ to prepare modified aluminum nitride powder.

[0017] Furthermore, the above-mentioned sintering aid is refined by sand milling as follows: yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide are selected as sintering aids. The sintering aids are sand milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1.2 μm. The sand milling temperature is 20–35°C, and then the sintering aid is dried in an oven at 80–100°C to obtain sintering aid powder with a density of 0.4–1.2 μm. The mass fraction of yttrium oxide in the sintering aid is 40–50%, the mass fraction of calcium fluoride is 25–35%, the mass fraction of magnesium fluoride is 15–25%, and the mass fraction of lanthanum oxide is 5–10%.

[0018] Furthermore, the above-mentioned primary and secondary ball milling methods are as follows: Modified aluminum nitride powder, sand-milled sintering aid, solvent, and dispersant are added to a ball mill and ball-milled for 16-24 hours. Then, binder and plasticizer are added and ball-milling continues for 16-24 hours (the purpose of the primary milling is to uniformly disperse aluminum nitride and sintering aid; the secondary ball milling is to add binder to make the slurry adhesive and the green body after casting has suitable strength). The solvent is anhydrous ethanol, the dispersant is ammonium polyacrylate, the binder is polyvinyl butyral, and the plasticizer is dibutyl phthalate.

[0019] Furthermore, the cut blanks are 30mm*50mm*1.5mm in size.

[0020] Furthermore, the above-mentioned glue removal method is as follows: the blank is placed in an atmosphere glue removal furnace for glue removal, and the glue removal temperature is 250-600℃.

[0021] Furthermore, the above sintering method is as follows: the green sheet after debinding is sintered at a temperature of 1750-1900℃, and then cooled to room temperature to obtain aluminum nitride ceramic sheet.

[0022] The beneficial effects of the present invention are as follows: Compared with the prior art, the present invention has the following advantages:

[0023] (1) Aluminum nitride ceramic material for HTCC is prepared by using modified alumina powder and other components in a certain proportion to achieve high thermal conductivity and high bending strength aluminum nitride ceramic, which solves the problem of low thermal conductivity of existing aluminum nitride ceramic. The thermal conductivity reaches more than 200W / (m·K) and the bending strength is more than 400Mpa, which can meet the requirements of device use, that is, it can meet the minimum thermal conductivity of 170W / (m·K) and minimum bending strength of 350Mpa required for aluminum nitride ceramic material for HTCC.

[0024] (2) Pretreatment of aluminum nitride powder and sintering aid prevents hydrolysis of the cast aluminum nitride raw tape during subsequent storage and pre-curing processes, forms an aluminum oxide film on the surface of aluminum nitride, eliminates the reaction between the aluminum oxide film and yttrium oxide to form yttrium aluminate phase, greatly reduces the content of yttrium aluminate phase between aluminum nitride grains, reduces the mismatch of thermal expansion coefficients between aluminum nitride and yttrium aluminate phase, and improves the strength of ceramics;

[0025] (3) As can be seen from the electron microscope images, the aluminum nitride ceramics obtained by using modified aluminum nitride powder and fine sintering aid have no pores in the cross section electron microscope, and the ceramic sintering density is better. Attached Figure Description

[0026] Figure 1 This is an electron microscope image of Comparative Example 1;

[0027] Figure 2 This is an electron microscope image of Example 1;

[0028] Figure 3 This is a flowchart of the preparation process. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Example: An aluminum nitride ceramic material for HTCC, comprising the following ingredients in the indicated mass ratio:

[0031] Aluminum nitride ceramic material is prepared from the above ingredients: 45-55g of modified aluminum nitride powder, 2-3g of sand milling and sintering aid, 30-40g of solvent, 1.5-5g of dispersant, 0.5-1g of binder, and 7-10g of plasticizer. The preparation method of this HTCC aluminum nitride ceramic material includes the following steps:

[0032] Step 1. Surface modification of aluminum nitride

[0033] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0034] Step 2. Milling of the calcining aid

[0035] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1.2 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0036] Step 3. Ball milling

[0037] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant are added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer are added and ball-milled for another 16–24 hours. The solvent is anhydrous ethanol, the dispersant is ammonium polyacrylate, the binder is polyvinyl butyral, and the plasticizer is dibutyl phthalate.

[0038] Step 4. Defoaming

[0039] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0040] Step 5. Casting

[0041] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0042] Step 6. Cutting

[0043] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0044] Step 7. Remove glue

[0045] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0046] Step 8. Sintering

[0047] After debinding, the green blanks are sintered at a temperature of 1750-1900℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0048] Example 1: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0049] 1. Surface modification of aluminum nitride

[0050] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride slurry was then dispersed evenly using a ball mill at a speed of 300–600 r / min for a dispersion time of 8–100 minutes.

[0051] 12h. The obtained uniformly mixed slurry was dried in an oven at a temperature of 80-100℃ to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling and anhydrous ethanol was 45-55:2-10:5-15:30-40.

[0052] 2. Milling of calcining aid

[0053] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a drying temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 45%, the mass fraction of calcium fluoride was 30%, the mass fraction of magnesium fluoride was 20%, and the mass fraction of lanthanum oxide was 5%.

[0054] 3. Ball mill

[0055] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 55:3:40:5:3:7. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0056] 4.Degassing

[0057] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0058] 5. Casting

[0059] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0060] 6. Cutting

[0061] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0062] 7. Degumming

[0063] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0064] 8. Sintering

[0065] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0066] Example 2: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0067] 1. Surface modification of aluminum nitride

[0068] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0069] 2. Milling of calcining aid

[0070] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0071] 3. Ball mill

[0072] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 55:2.5:35:3:2:6. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0073] 4.Degassing

[0074] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0075] 5. Casting

[0076] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0077] 6. Cutting

[0078] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0079] 7. Degumming

[0080] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0081] 8. Sintering

[0082] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0083] Example 3: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0084] 1. Surface modification of aluminum nitride

[0085] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0086] 2. Milling of calcining aid

[0087] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0088] 3. Ball mill

[0089] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 55:2:30:1.5:1:5. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0090] 4.Degassing

[0091] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0092] 5. Casting

[0093] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0094] 6. Cutting

[0095] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0096] 7. Degumming

[0097] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0098] 8. Sintering

[0099] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0100] Example 4: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0101] 1. Surface modification of aluminum nitride

[0102] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0103] 2. Milling of calcining aid

[0104] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0105] 3. Ball mill

[0106] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 50:3:40:5:3:7. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0107] 4.Degassing

[0108] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0109] 5. Casting

[0110] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0111] 6. Cutting

[0112] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0113] 7. Degumming

[0114] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0115] 8. Sintering

[0116] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0117] Example 5: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0118] 1. Surface modification of aluminum nitride

[0119] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0120] 2. Milling of calcining aid

[0121] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0122] 3. Ball mill

[0123] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 50:2.5:35:3:2:6. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0124] 4.Degassing

[0125] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0126] 5. Casting

[0127] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0128] 6. Cutting

[0129] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0130] 7. Degumming

[0131] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0132] 8. Sintering

[0133] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0134] Example 6: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0135] 1. Surface modification of aluminum nitride

[0136] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0137] 2. Milling of calcining aid

[0138] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0139] 3. Ball mill

[0140] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant are added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer are added, and ball milling continues for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used is 50:2:30:1.5:1:5. The solvent is anhydrous ethanol, the dispersant is ammonium polyacrylate, the binder is polyvinyl butyral, and the plasticizer is dibutyl phthalate.

[0141] 4.Degassing

[0142] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0143] 5. Casting

[0144] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0145] 6. Cutting

[0146] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0147] 7. Degumming

[0148] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0149] 8. Sintering

[0150] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0151] Example 7: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0152] 1. Surface modification of aluminum nitride

[0153] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0154] 2. Milling of calcining aid

[0155] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0156] 3. Ball mill

[0157] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 45:3:40:5:3:7. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0158] 4.Degassing

[0159] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0160] 5. Casting

[0161] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0162] 6. Cutting

[0163] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0164] 7. Degumming

[0165] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0166] 8. Sintering

[0167] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0168] Example 8: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0169] 1. Surface modification of aluminum nitride

[0170] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0171] 2. Milling of calcining aid

[0172] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0173] 3. Ball mill

[0174] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 45:2.5:35:3:2:6. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0175] 4.Degassing

[0176] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0177] 5. Casting

[0178] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0179] 6. Cutting

[0180] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0181] 7. Degumming

[0182] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0183] 8. Sintering

[0184] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0185] Example 9: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0186] 1. Surface modification of aluminum nitride

[0187] AlN powder, citric acid, and silane coupling agent were added to an appropriate amount of anhydrous ethanol. The aluminum nitride mixture was then dispersed uniformly using a ball mill at a speed of 300–600 r / min for 8–12 h. The resulting uniform mixture was dried in an oven at 80–100 °C to prepare modified aluminum nitride powder. The mass ratio of AlN powder, citric acid, silane coupling agent, and anhydrous ethanol was 45–55:2–10:5–15:30–40.

[0188] 2. Milling of calcining aid

[0189] Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide were selected as sintering aids. The sintering aids were milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4–1 μm at a milling temperature of 20–35 °C. Then, the sintering aid was dried in an oven at a temperature of 80–100 °C to obtain a finer sintering aid powder. The mass fraction of yttrium oxide in the sintering aid was 40–50%, the mass fraction of calcium fluoride was 25–35%, the mass fraction of magnesium fluoride was 15–25%, and the mass fraction of lanthanum oxide was 5–10%.

[0190] 3. Ball mill

[0191] Modified aluminum nitride powder, refined sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of modified aluminum nitride powder, sand milling sintering aid, solvent, dispersant, binder, and plasticizer used was 45:2:30:1.5:1:5. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0192] 4.Degassing

[0193] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0194] 5. Casting

[0195] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0196] 6. Cutting

[0197] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0198] 7. Degumming

[0199] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0200] 8. Sintering

[0201] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0202] Comparative Example 1: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0203] 1. Ball mill

[0204] Aluminum nitride powder, sintering aid, solvent, and dispersant are added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer are added, and ball milling continues for another 16–24 hours. The mass ratio of aluminum nitride powder, sintering aid, solvent, dispersant, binder, and plasticizer used is 55:3:40:5:3:7. The sintering aid is yttrium oxide, the solvent is anhydrous ethanol, the dispersant is ammonium polyacrylate, the binder is polyvinyl butyral, and the plasticizer is dibutyl phthalate.

[0205] 2.Degassing

[0206] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0207] 3. Casting

[0208] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0209] 4. Cutting

[0210] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0211] 5. Degumming

[0212] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0213] 6. Sintering

[0214] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0215] Comparative Example 2: A method for preparing aluminum nitride ceramic material for HTCC, comprising the following steps:

[0216] 1. Ball mill

[0217] Aluminum nitride powder, sintering aid, solvent, and dispersant were added to a ball mill and ball-milled for 16–24 hours. Then, binder and plasticizer were added, and ball milling continued for another 16–24 hours. The mass ratio of aluminum nitride powder, sintering aid, solvent, dispersant, binder, and plasticizer used was 55:3:40:5:3:7. The sintering aid contained 45% yttrium oxide, 30% calcium fluoride, 20% magnesium fluoride, and 5% lanthanum oxide. The solvent was anhydrous ethanol, the dispersant was ammonium polyacrylate, the binder was polyvinyl butyral, and the plasticizer was dibutyl phthalate.

[0218] 2.Degassing

[0219] The ball-milled material is fed into a degassing machine for degassing treatment to obtain ceramic slurry.

[0220] 3. Casting

[0221] The degassed ceramic slurry is cast into a green belt using a casting machine.

[0222] 4. Cutting

[0223] Cut the green strip into blanks measuring 30mm*50mm*1.5mm.

[0224] 5. Degumming

[0225] The blank is placed in an atmosphere debinding furnace for debinding, and the debinding temperature is 250-600℃.

[0226] 6. Sintering

[0227] After debinding, the green blanks are sintered at a temperature of 1850℃ and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

[0228] A high thermal conductivity and high flexural strength aluminum nitride ceramic material for HTCC (High-Temperature Hydrocarbon Ceramic) is disclosed, exhibiting a thermal conductivity greater than 200 W / (m·K) and a flexural strength greater than 400 MPa. The aluminum nitride ceramic prepared by this invention possesses excellent thermal and mechanical properties, primarily attributed to the modification of aluminum nitride and the refinement of the sintering aid. This promotes the densification of the aluminum nitride ceramic, improves its microstructure, grain size, and the composition and distribution of crystalline phases, thereby enhancing the overall performance of the aluminum nitride ceramic. Table 1 shows the density, thermal conductivity, and flexural strength of each embodiment and comparative example. It can be seen that Embodiments 1, 2, and 3 exhibit superior performance compared to Comparative Examples 1 and 2. Figure 1 , Figure 2 The electron microscopy results of Comparative Example 1 and Example 1 show that the aluminum nitride ceramics obtained by using modified aluminum nitride powder and refining sintering aid have no pores in the cross-section electron microscopy, indicating that the ceramics have reached a dense sintering degree.

[0229] Table 1 Thermal conductivity and flexural strength

[0230] Example 1 3.36 206 420 Example 2 3.35 220 432 Example 3 3.35 210 450 Example 4 3.35 203 441 Example 5 3.36 208 428 Example 6 3.37 214 409 Example 7 3.35 223 460 Example 8 3.36 205 430 Example 9 3.36 216 421 Comparative Example 1 3.29 170 380 Comparative Example 2 3.32 185 401

[0231] 2. The ceramic material formula is as follows: the mass ratio of modified aluminum nitride powder, sand milling and sintering aid, solvent, dispersant, binder and plasticizer is 45-55:2-3:30-40:1.5-5:1-3:5-7.

[0232] In Example 1, the mass ratio of aluminum nitride ceramic was aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 55:1.35:0.9:0.6:0.15; in Example 2, the mass ratio was aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 55:1.125:0.75:0.5:0.125; and in Example 3, the mass ratio was aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride. The mass ratio of aluminum nitride ceramic in Example 4 was 50:1.35:0.9:0.6:0.15: ... The mass ratio of the aluminum nitride ceramic in Example 7 was 50:1.35:0.9:0.6:0.15; the mass ratio of the aluminum nitride ceramic in Example 8 was 45:1.35:0.9:0.6:0.15; the mass ratio of the aluminum nitride ceramic in Example 9 was 45:1.35:0.9:0.6:0.15. The mass ratio of aluminum nitride ceramic in Example 9 was 9:0.6:0.15; the mass ratio of aluminum nitride ceramic in Comparative Example 1 was 50:3; the mass ratio of aluminum nitride ceramic in Comparative Example 2 was 50:1.35:0.9:0.6:0.15.

[0233] The present invention has the following advantages:

[0234] 1. Pretreatment of aluminum nitride powder and sintering aids prevents hydrolysis of the cast aluminum nitride raw tape during subsequent storage and pre-curing processes, forming an alumina film on the surface of aluminum nitride. This eliminates the reaction between the alumina film and yttrium oxide to form the yttrium aluminate phase, greatly reducing the content of the yttrium aluminate phase between aluminum nitride grains, reducing the mismatch in thermal expansion coefficients between aluminum nitride and the yttrium aluminate phase, and improving the strength of the ceramic.

[0235] 2. In the ceramic material formulation, the mass ratio of aluminum nitride ceramic in Example 1 is aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 55:1.35:0.9:0.6:0.15; the mass ratio of aluminum nitride ceramic in Example 2 is aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 55:1.125:0.75:0.5:0.125; the mass ratio of aluminum nitride ceramic in Example 3 is aluminum nitride: yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 55:1.125:0.75:0.5:0.125. Calcium: Magnesium fluoride: Lanthanum oxide = 55:0.9:0.6:0.4:0.1; The mass ratio of aluminum nitride ceramic in Example 4 is aluminum nitride:yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 50:1.35:0.9:0.6:0.15; The mass ratio of aluminum nitride ceramic in Example 5 is aluminum nitride:yttrium oxide: calcium fluoride: magnesium fluoride: lanthanum oxide = 50:1.125:0.75:0.5:0.125; The mass ratio of aluminum nitride ceramic in Example 6 is... The mass ratio of aluminum nitride ceramics in Example 7 was 50:1.35:0.9:0.6:0.15; the mass ratio of aluminum nitride ceramics in Example 8 was 45:1.35:0.9:0.6:0.15; and the mass ratio of aluminum nitride ceramics in Example 9 was 45:1.35:0.9:0.6:0.15. The mass ratio of aluminum nitride ceramic in Example 9 was 0.9:0.6:0.15; the mass ratio of aluminum nitride ceramic in Comparative Example 1 was 50:3; the mass ratio of aluminum nitride ceramic in Comparative Example 2 was 50:1.35:0.9:0.6:0.15.

[0236] 3. The electron microscopy results of Comparative Example 1 and Example 1 show that the aluminum nitride ceramics obtained by using modified aluminum nitride powder and refining sintering aid have no pores in the cross-section electron microscopy, and the ceramic sintering density is better.

[0237] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. An aluminum nitride ceramic material for HTCC, characterized in that: The ingredients include the following mass ratio: Aluminum nitride ceramic material is prepared from the following ingredients: 45-55g of modified aluminum nitride powder, 2-3g of sand milling and sintering aid, 30-40g of solvent, 1.5-5g of dispersant, 1-3g of binder and 5-7g of plasticizer. Modified aluminum nitride powder formulation: The mass ratio of AlN powder, citric acid, silane coupling and anhydrous ethanol is 45-55: 2-10: 5-15: 30-40; The sintering aid contains 40-50% yttrium oxide, 25-35% calcium fluoride, 15-25% magnesium fluoride, and 5-10% lanthanum oxide by mass.

2. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 1, characterized in that: The method includes the following steps: Step 1, Modification and Milling: The aluminum nitride powder is surface modified and refined by milling with sintering aids; Step 2, primary and secondary ball milling: The modified aluminum nitride powder, the sintering aid refined by sand milling, the solvent and the dispersant are added together to the ball mill for primary ball milling. After the primary ball milling, the binder and plasticizer are added for secondary ball milling. Step 3, Degassing: After secondary ball milling, the slurry after ball milling is degassed using a vacuum degassing machine to obtain ceramic slurry; Step 4: Casting and Shaping: The ceramic slurry is cast and dried to obtain a ceramic green body; Step 5: Slicing: Cut the ceramic green body into slices; Step 6, Debinding: Place the blank into the debinding furnace for debinding; Step 7, Sintering: High thermal conductivity and high bending strength aluminum nitride ceramics are obtained by high-temperature sintering in a vacuum furnace.

3. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The surface modification treatment formula is: aluminum nitride powder, citric acid, silane coupling and anhydrous ethanol in a mass ratio of 45-55:2-10:5-15:30-40.

4. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The surface modification method is as follows: aluminum nitride powder, citric acid and silane coupling agent are added to 40% wt anhydrous ethanol at a mass ratio of 45%:5%:10% to obtain an aluminum nitride mixed slurry. The aluminum nitride mixed slurry is dispersed evenly using a ball mill at a speed of 300-600 r / min for a dispersion time of 8-12 h. The uniform aluminum nitride mixed slurry after ball milling is placed in an oven for drying at a temperature of 80-100℃ to prepare modified aluminum nitride powder.

5. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The method for refining the sintering aid by sand milling is as follows: Yttrium oxide, calcium fluoride, magnesium fluoride, and lanthanum oxide are selected as sintering aids. The sintering aids are sand milled in anhydrous ethanol to obtain a sintering aid slurry with a D50 of 0.4 to 1.2 μm. The sand milling temperature is 20 to 35°C. Then, the sintering aid is dried in an oven at a temperature of 80 to 100°C to obtain sintering aid powder with a particle size of 0.4 to 1.2 μm.

6. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The primary and secondary ball milling methods are as follows: Modified aluminum nitride powder, sintering aid refined by sand milling, solvent, and dispersant are added into a ball mill and ball milled for 16-24 hours. Then, binder and plasticizer are added and ball milling is continued for 16-24 hours. The solvent is anhydrous ethanol, the dispersant is ammonium polyacrylate, the binder is polyvinyl butyral, and the plasticizer is dibutyl phthalate.

7. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The cut blanks are 30mm*50mm*1.5mm in size.

8. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The glue removal method is as follows: the blank is placed in an atmosphere glue removal furnace for glue removal, and the glue removal temperature is 250-600℃.

9. The method for preparing an aluminum nitride ceramic material for HTCC according to claim 2, characterized in that: The sintering method is as follows: the green blanks after debinding are sintered at a temperature of 1750-1900℃, and then cooled to room temperature to obtain aluminum nitride ceramic sheets.

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