Green ceramic slurry and preparation method thereof, zirconia composite alumina green ceramic and preparation method thereof

Abstract

This invention relates to the field of high-temperature co-fired ceramics technology, and particularly to green ceramic slurry and its preparation method, and zirconia-alumina composite green ceramic and its preparation method. The preparation method of the green ceramic slurry includes: S1: mixing a first dispersant, a coupling agent, zirconia powder, and a first organic solvent, followed by ball milling and drying to obtain modified zirconia powder; S2: mixing the modified zirconia powder, alumina powder, a second dispersant, and a second organic solvent, followed by ball milling to prepare a first slurry; S3: mixing the first slurry with a binder solution and continuing ball milling, adding a plasticizer after ball milling, and continuing ball milling to obtain the green ceramic slurry. This invention, by modifying the zirconia powder and optimizing the mixing steps, can improve the mixing uniformity, enhance the dispersion effect of the powder and slurry, and thus improve the flexural strength of the green ceramic.

Description

Technical Field

[0001] This invention relates to the field of high-temperature co-fired ceramics technology, and particularly to green ceramic slurry and its preparation method, and zirconia composite alumina green ceramic and its preparation method. Background Technology

[0002] Zirconia ceramics possess advantages such as high strength, high temperature resistance, and good chemical stability, and are widely used in electronics, machinery, chemical industry, aerospace, and other fields. However, zirconia ceramics are usually prepared using nano-zirconia, which presents drawbacks such as difficulty in powder dispersion, greatly increasing the difficulty of their preparation. Alumina ceramics have advantages such as high temperature resistance, wear resistance, electrical insulation, low loss, and good chemical stability, and their raw materials are abundant, making them one of the most widely used ceramic packaging materials in the electronics industry. Alumina ceramics are widely used in aerospace, power devices, sensors, and other fields. However, they still suffer from drawbacks such as low strength and poor fracture toughness, which restricts their development.

[0003] Zirconia-alumina composite ceramics are ceramic products obtained by co-sintering alumina powder with an appropriate amount (8wt%-15wt%) of zirconia powder. The presence of an appropriate amount of zirconia can enhance the strength of alumina ceramics while retaining their original advantages. The main mechanisms are stress-induced phase transformation toughening and microcrack toughening. Currently, research on zirconia-alumina composite ceramics mainly focuses on the preparation of mixed alumina and zirconia powders and single-layer zirconia-alumina composite ceramic plates. The latter is mostly used in DBC / AMB copper-clad laminates, while research and application of multilayer zirconia-alumina composite ceramic materials are relatively limited.

[0004] Multilayer ceramic materials are often prepared using the tape casting method. Powder is mixed uniformly with solvents, binders, dispersants, plasticizers, etc., and the mixture is cast into a slurry to form green ceramic. Subsequently, the layers are stacked and sintered to obtain a multilayer ceramic substrate. Zirconia-alumina composite ceramics are prepared using nano-alumina powder and zirconia powder. Due to their large surface energy, nano-powders typically exhibit the disadvantages of easy agglomeration and difficulty in dispersion. Therefore, whether the powder is sufficiently dispersed in the slurry and whether the two powders are uniformly mixed are crucial to ensuring the high strength of zirconia-alumina composite ceramics.

[0005] Therefore, this invention is proposed. Summary of the Invention

[0006] To address the challenges of dispersing zirconia powder and the lack of research on multilayer zirconia-alumina composite ceramic substrates in existing technologies, this invention provides a green ceramic slurry and its preparation method, as well as a zirconia-alumina composite green ceramic and its preparation method.

[0007] Based on this, the present invention has the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a green ceramic slurry, comprising:

[0009] S1: The first dispersant, coupling agent, zirconium oxide powder and the first organic solvent are mixed, and modified zirconium oxide powder is obtained after ball milling and drying.

[0010] S2: The modified zirconium oxide powder, alumina powder, second dispersant, and second organic solvent are mixed and ball-milled to prepare the first slurry;

[0011] S3: Mix the first slurry with the binder solution and continue ball milling. After ball milling, add the plasticizer and continue ball milling to obtain the green ceramic slurry.

[0012] This invention modifies zirconia powder using a coupling agent, followed by ball milling and drying to obtain modified zirconia powder. This step improves the organic affinity and lubricity of the zirconia powder, facilitating its dispersion in slurry. Subsequently, the solvent, dispersant, alumina powder, and modified zirconia powder are ball-milled to obtain a modified zirconia-alumina composite powder. This step ensures thorough dispersion of the alumina powder and uniform mixing of the modified zirconia and alumina. Furthermore, the absence of a binder in this step prevents the binder and dispersant from affecting the powder dispersion due to their different dispersion mechanisms. Pre-dissolving the binder and mixing the binder solution with the modified zirconia-alumina composite powder followed by re-ball milling ensures thorough mixing of the powder and binder and effectively prevents undissolved binder particles from remaining in the slurry.

[0013] Preferably, the coupling agent includes an aluminate coupling agent and / or a titanate coupling agent; more preferably, the amount of the coupling agent added is 1wt% to 3wt% of the mass of the zirconium oxide powder.

[0014] Preferably, the first dispersant and the second dispersant each independently, identically or differently comprise one or more of EW20000, BYK22552, LD1140 and LD1132-50; more preferably, the first dispersant and the second dispersant each independently, identically or differently comprise BYK22552 and / or LD1132-50.

[0015] More preferably, the amount of the first dispersant added is 0.5wt% to 2.5wt% of the mass of the zirconium oxide powder; the amount of the second dispersant added is 0.5wt% to 2.5wt% of the total mass of the modified zirconium oxide powder and the alumina powder.

[0016] Preferably, the zirconium oxide powder is nano-monoclinic zirconium oxide powder with a D50 of 400~600nm; and / or, the alumina powder is nano-alumina powder with a D50 of 400~600nm.

[0017] More preferably, the mass of the modified zirconium oxide powder is 8wt% to 15wt% of the mass of the alumina powder.

[0018] Preferably, a first ball milling medium is added during mixing in S1, and a second ball milling medium is added during mixing in S2; wherein the particle size of the first ball milling medium is 1~5mm, and the particle size of the second ball milling medium is 10~15mm.

[0019] In this invention, the first ball milling medium is used to enable the powder to be better dispersed during ball milling, and the second ball milling medium is used to mix the slurry evenly.

[0020] Preferably, the binder solution includes a binder and an organic solvent, wherein the binder includes one of PVB and / or PMMA, and the organic solvent includes one or more of acetone, butanone, ethyl acetate and butyl acetate; more preferably, the amount of binder added is 8wt% to 12wt% of the total mass of the modified zirconia powder and the alumina powder.

[0021] Preferably, the plasticizer is one or more of dibutyl phthalate and dioctyl phthalate.

[0022] Secondly, the present invention provides a green ceramic slurry, which is prepared by the above-mentioned method for preparing green ceramic slurry.

[0023] Thirdly, the present invention provides a method for preparing zirconia composite alumina green ceramic, comprising: allowing the green ceramic slurry to stand and degas, and then casting it to obtain zirconia composite alumina green ceramic, wherein the casting speed is 0.4~0.5m / min.

[0024] This invention reveals that the green ceramic prepared by this method has good surface quality and an average flexural strength ≥600MPa after lamination and sintering.

[0025] Fourthly, the present invention provides a zirconia composite alumina green ceramic, which is prepared by the aforementioned method for preparing zirconia composite alumina green ceramic.

[0026] The green ceramic slurry and its preparation method, and the zirconia composite alumina green ceramic and its preparation method provided by the present invention, by modifying the zirconia powder and optimizing the mixing steps, can improve the mixing uniformity, improve the dispersion effect of the powder and slurry, and thus improve the flexural strength of the green ceramic. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a SEM image of the zirconium oxide composite alumina green ceramic of Example 1 provided by the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0031] Example 1

[0032] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0033] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of BYK22552, 100g each of anhydrous ethanol and methyl ethyl ketone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0034] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0035] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0036] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0037] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0038] ⑤ After ball milling, filter out the above raw ceramic slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0039] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T1.

[0040] Example 2

[0041] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0042] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0043] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0044] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0045] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0046] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0047] ⑤ After ball milling, filter out the above slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0048] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T2.

[0049] Example 3

[0050] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0051] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0052] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0053] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0054] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0055] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0056] ⑤ After ball milling, filter out the above slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0057] ⑥ The above slurry was cast into green ceramic at a speed of 0.5 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T3.

[0058] Example 4

[0059] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0060] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of titanate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0061] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0062] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0063] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0064] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0065] ⑤ After ball milling, filter out the above slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0066] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T4.

[0067] Example 5

[0068] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0069] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of EW20000, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0070] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0071] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0072] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0073] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0074] ⑤ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0075] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T5.

[0076] Example 6

[0077] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0078] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1140, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0079] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0080] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0081] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0082] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0083] ⑤ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0084] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T6.

[0085] Example 7

[0086] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0087] ① Weigh 900g of 10mm zirconia column, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0088] ② Weigh 4000g of 10mm zirconia column, 265g each of anhydrous ethanol and methyl ethyl ketone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0089] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0090] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0091] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0092] ⑤ After ball milling, filter out the above slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0093] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, layered, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered T7.

[0094] Comparative Example 1

[0095] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0096] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of nano zirconia powder, 20g of BYK22552, 100g each of anhydrous ethanol and methyl ethyl ketone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0097] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0098] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0099] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0100] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0101] ⑤ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0102] ⑥ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered A1.

[0103] Comparative Example 2

[0104] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0105] ① Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 100g of nano zirconia powder, and 900g of nano alumina powder and place them in a 5L ball mill jar;

[0106] ② Add 365g each of anhydrous ethanol and butanone, 20g of BYK22552, 120g of PVB, and 72g of DBP to the above-mentioned ball mill jar;

[0107] ② Place the ball mill jar on the roller mill. Adjust the speed to 70 r / min for ball milling. After ball milling for 7 hours, adjust the speed to 30 r / min and continue ball milling for 17 hours to obtain the green ceramic slurry.

[0108] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0109] ③ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0110] ④ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, layered, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered A2.

[0111] Comparative Example 3

[0112] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0113] ① Weigh 3000g of a 10mm zirconia column, 1000g of a 15mm zirconia column, 365g each of anhydrous ethanol and butanone, 20g of BYK22552, and 120g of PVB and place them in a 5L ball mill jar;

[0114] ② Place the ball mill jar on the roller mill, adjust the speed to 70 r / min for ball milling, remove the ball mill jar after 3 hours of ball milling, add 100g of nano zirconia powder and 900g of nano alumina powder, and continue ball milling for 4 hours;

[0115] ③ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0116] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0117] ④ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0118] ⑤ The above slurry was cast into green ceramic at a speed of 0.4 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered A3.

[0119] Comparative Example 4

[0120] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0121] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0122] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0123] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0124] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0125] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0126] ⑤ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0127] ⑥ The above slurry was cast into green ceramic at a speed of 0.3 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered A4.

[0128] Comparative Example 5

[0129] This embodiment provides a green ceramic slurry, the preparation method of which includes the following steps:

[0130] ① Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0131] ② Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h.

[0132] ③ After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7 hours;

[0133] ④ After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min, and continue ball milling for 17h to obtain the raw ceramic slurry.

[0134] This embodiment further provides a zirconia composite alumina green ceramic, the preparation method of which includes the following steps:

[0135] ⑤ After ball milling, filter out the slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment;

[0136] ⑥ The above slurry was cast into green ceramic at a speed of 0.6 m / min, then cut, stacked, hot-pressed, and cut into strips 40 mm long, 6 mm wide, and 5 mm thick. After sintering, the flexural strength was tested. The sample was numbered A5.

[0137] Test case

[0138] The present invention further tested the flexural strength of the green ceramics in the above embodiments and comparative examples, and the results are shown in Table 1.

[0139] Test method: GB / T 6569-2006

[0140] Table 1 Flexural strength of zirconia composite alumina substrate

[0141]

[0142] As shown in Table 1, the flexural strength of the zirconia composite alumina green ceramic can reach over 600 MPa. Comparing the experimental results of Comparative Example 1, Example 1, and Example 5, it can be seen that the zirconia composite alumina green ceramic prepared using modified zirconia powder can significantly improve the flexural strength of the material. The modified zirconia powder has strong organic affinity and lubricity, promoting the dispersion of zirconia powder. Simultaneously, the sintered product of the selected aluminate coupling agent can further improve the interfacial bonding between zirconia and alumina, while the sintered product of the titanate coupling agent can promote the sintering of alumina powder. The experimental results of Examples 1, 2, 5, and 6 demonstrate that dispersant LD1132-50 has the best dispersion effect on zirconia. Dispersant LD1132-50 is a modified styrene-maleic acid polymer with a variety of functional groups. Its nonpolar benzene rings and hydrocarbon chains can be adsorbed on the nonpolar surface of particles, while polar groups or side chains cover the surface of nonpolar particles, generating electrostatic repulsion, thereby enhancing the dispersion. Dispersant LD1140 is a block copolymer with conjugated groups. This dispersant increases slurry viscosity and affects powder dispersibility. Dispersant EW20000 is a polymer dispersant with 100% active ingredient content. This dispersant easily leads to interpenetration of particle adsorption layers, causing entropy increase, system free energy decrease, and particle agglomeration. Dispersant BYK22552 is a copolymer solution containing filler groups. The -COOH group in it can adsorb onto the particle surface to form a steric layer, producing a steric hindrance effect. However, single functional groups have poor powder dispersion effect, resulting in a large degree of material strength dispersion. The same conclusion can also be obtained from SEM images. The experimental results of Examples 3 and 4 and Comparative Examples 4 and 5 show that both excessively fast and slow flow rates lead to a decrease in flexural strength. The experimental results of Examples 2 and 7 show that using small-diameter grinding balls with different particle sizes has a significant promoting effect on powder dispersion. At the same time, using large-diameter grinding columns with different particle sizes can ensure that the slurry is fully mixed and improve the material strength.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing zirconia composite alumina green ceramic, characterized in that, Includes the following steps: (1) Weigh 400g of 3mm zirconia balls, 500g of 5mm zirconia balls, 100g of aluminate coupling agent modified nano zirconia powder, 20g of LD1132-50, 100g each of anhydrous ethanol and butanone, and place them in a 2L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h. (2) Weigh 3000g of 10mm zirconia column, 1000g of 15mm zirconia column, 265g each of anhydrous ethanol and butanone, and 120g of PVB and place them in a 5L ball mill jar. Adjust the speed of the roller mill to 70r / min and ball mill for 24h. (3) After ball milling, filter the slurry in the 2L ball mill jar through an 80-mesh sieve into the 5L ball mill jar, and add 900g of nano alumina powder to continue ball milling for 7h. (4) After ball milling, remove the ball mill jar, add 72g of DBP, adjust the speed of the roller mill to 30r / min and continue ball milling for 17h to obtain raw ceramic slurry; (5) After ball milling, filter out the above slurry and let it stand for 15 minutes, followed by 20 minutes of degassing treatment; (6) The above slurry is cast into green porcelain at a speed of 0.4 m / min.

Images