Ultrahigh-density aluminum oxide ceramic material and preparation method thereof

Abstract

The invention relates to an ultrahigh-density aluminum oxide ceramic material and a preparation method thereof. The preparation method specifically comprises the following steps: weighing raw materials, carrying out ball milling on aluminum oxide powder and deionized water, sieving and stirring slurry after ball milling, adding PVC resin and a polyvinyl alcohol solution while stirring, and adding a plasticizer after stirring; adding stearic acid emulsion after stirring; after stirring, oxalic acid is added to adjust the pH value, stirring is performed, and the slurry is subjected to spray granulation treatment and sieving; and carrying out cold isostatic pressing and sintering treatment on the granulated powder to obtain the ultra-high-density aluminum oxide ceramic material. By optimizing the composition of the plasticizer, the ceramic body density of the ceramic material is greatly improved, the product performance of the aluminum oxide ceramic material is improved, and the high-end application scene of the aluminum oxide ceramic material is expanded.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alumina ceramics, and particularly relates to an ultrahigh-density alumina ceramic material and a preparation method thereof. BACKGROUND

[0002] Alumina ceramics are widely used in electronic substrates, mechanical seals, cutting tools and optical elements due to their high hardness, excellent insulation, corrosion resistance and high temperature stability. The performance of the material is highly dependent on its density: high density can significantly improve the mechanical strength (such as bending strength), insulation and light transmission, especially in high-pressure sodium lamp arc tubes, infrared windows and other optical applications, the degree of densification directly affects the light transmission. The existing technology mainly improves the density through three ways of sintering process optimization, additive control and structure design, but there are still significant limitations:

[0003] (1) Sintering process improvement: atmospheric sintering is the basic process, but it needs high temperature and it is difficult to completely eliminate closed pores; special sintering technology promotes densification by external pressure, but the equipment cost is high, it is difficult to scale up, and complex-shaped products are prone to deformation; new sintering processes such as flash sintering use electric field to assist in generating Joule heating effect, achieving rapid densification, and the grain size is smaller, but the parameter control is complex, and the uniformity of large-size products is poor.

[0004] (2) Additives and dispersants control: the introduction of sintering aids can reduce the sintering temperature and inhibit abnormal grain growth, but residual impurities will reduce the purity of the material and affect the high temperature stability. Dispersant optimization improves the dispersion of the slurry to reduce particle agglomeration, improves the uniformity of the green body, and increases the relative density after sintering.

[0005] (3) Post-processing and structure design: hot isostatic pressing post-processing can make the density reach the peak, but it needs pre-sintering encapsulation, which is complicated and costly. Liquid phase infiltration technology is used for binder jetting formed parts, but gravity infiltration leads to uneven density distribution and difficulty in controlling size accuracy. The ordered structure design indirectly improves the densification by hindering crack propagation, but the process is complex and only suitable for specific functional devices.

[0006] Chinese patent CN202411992928.2 discloses an alumina ceramic granulating powder, a preparation method thereof and a high-density alumina ceramic, and the density of the ceramic body can reach 3.944 g / cm 3 , which still has a significant gap from the goal of complete densification of ultrahigh-density alumina ceramics. This density bottleneck limits the service reliability of the material under extreme conditions of high temperature and high pressure, high wear resistance, etc., and it is difficult to meet the strict requirements of high-end fields such as precision ceramic bearings and core components of semiconductor equipment for zero-pore-defect ceramics. Therefore, further improving the absolute density of alumina ceramics to > 4.5 g / cm 3 is still a technical direction that needs to be broken through at present. SUMMARY

[0007] In order to solve the above technical problems, the present application provides a preparation method of ultra-high density alumina ceramic material, comprising the following steps:

[0008] S1: weighing raw materials: alumina powder, deionized water, PVC resin, polyvinyl alcohol solution, plasticizer, stearic acid emulsion; the plasticizer is selected from one or more of acetyl tri (ethylhexyl) citrate, polybutylene succinate 1,6-hexanediol PHS, epoxy acetyl methyl castor oil acid;

[0009] S2: ball milling the alumina powder and deionized water;

[0010] S3: sieving and stirring the slurry after ball milling, adding PVC resin and polyvinyl alcohol solution while stirring; adding plasticizer after stirring; adding stearic acid emulsion after stirring; adjusting pH to 8 by adding oxalic acid after stirring; stirring;

[0011] S4: spray granulation treatment of the slurry, sieving;

[0012] S5: cold isostatic pressing and sintering treatment of the granulated powder to obtain ultra-high density alumina ceramic material.

[0013] Preferably, the plasticizer is selected from two of acetyl tri (ethylhexyl) citrate, polybutylene succinate 1,6-hexanediol PHS, epoxy acetyl methyl castor oil acid.

[0014] Preferably, the plasticizer is composed of acetyl tri (ethylhexyl) citrate, polybutylene succinate 1,6-hexanediol PHS, and epoxy acetyl methyl castor oil acid.

[0015] Preferably, the plasticizer is composed of acetyl tri (ethylhexyl) citrate, polybutylene succinate 1,6-hexanediol PHS, and epoxy acetyl methyl castor oil acid in a mass ratio of 1:1:1.

[0016] Preferably, in S1, the alumina powder is 20 kg, the deionized water is 6.67 kg, the PVC resin is 0.14 kg, the polyvinyl alcohol solution is 1 kg, the plasticizer is 0.6 kg, and the stearic acid emulsion is 0.36 kg.

[0017] Preferably, in S2, the ball milling parameters include: mass 40 kg, speed 35 Hz, and time 3 h.

[0018] Preferably, S3 specifically includes: sieving and stirring the slurry after ball milling, adding PVC resin and polyvinyl alcohol solution while stirring; adding plasticizer after stirring for 60 min; adding stearic acid emulsion after stirring for 30 min; adjusting pH to 8 by adding oxalic acid after stirring for 30 min; and finally stirring for another 30 min.

[0019] Preferably, S4 specifically comprises: spray granulation treatment is carried out on the slurry, inlet / outlet temperature 160℃ / 100℃, atomizing disc rotation speed 30Hz; screening treatment is carried out to obtain granulated powder of 45-60um.

[0020] Preferably, S5 specifically comprises: the granulated powder is subjected to 130MPa cold isostatic pressing and sintering treatment to obtain the ultra-high density alumina ceramic material.

[0021] The application also provides an ultra-high density alumina ceramic material prepared by the above preparation method.

[0022] Compared with the prior art, the application greatly improves the density of the ceramic material by optimizing the composition of the plasticizer, and the highest density can reach 5.28g / cm 3 , which is about 34% higher than the prior art. This significant improvement is due to the synergistic mechanism of the ternary plasticizer, which optimizes the powder dispersibility, reduces the porosity, enhances the stability of the structure, and promotes sintering densification, thereby laying a key foundation for the industrial application of high-performance ceramics. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0024] Embodiment 1

[0025] A preparation method of an ultra-high density alumina ceramic material, comprising the following steps:

[0026] S1: the raw materials are weighed as follows: alumina powder 20kg, deionized water 6.67kg, PVC resin 0.14kg, polyvinyl alcohol solution 1kg, plasticizer 0.6kg (acetyl tri(ethylhexyl) citrate 0.2kg, polybutylene succinate 1,6-hexanediol ester (PHS) 0.2kg, epoxy acetyl castor oil acid methyl ester 0.2kg), stearic acid emulsion 0.36kg.

[0027] S2: the alumina powder and deionized water are subjected to ball milling, and the ball milling parameters include: mass 40kg, speed 35Hz, time 3h.

[0028] S3: the slurry after ball milling is subjected to screening and stirring treatment, and the PVC resin and polyvinyl alcohol solution are added while stirring; the plasticizer is added after stirring for 60min; the stearic acid emulsion is added after stirring for 30min; the oxalic acid is added to adjust the pH to 8 after stirring for 30min; and finally, stirring is carried out for another 30min.

[0029] S4 spray granulation treatment of slurry, inlet / outlet temperature 160℃ / 100℃, atomizing disc speed 30Hz; sieve treatment, 45-60um granulation powder.

[0030] S5 granulation powder 130MPa cold isostatic pressing and sintering treatment, obtain super high density alumina ceramic material.

[0031] Example 2

[0032] A method for preparing a super high density alumina ceramic material, comprising the following steps:

[0033] S1 weigh the raw materials as follows: alumina powder 20kg, deionized water 6.67kg, PVC resin 0.14kg, polyvinyl alcohol solution 1kg, plasticizer 0.6kg (polybutylene succinate 1,6-hexanediol ester (PHS) 0.3kg, epoxy acetyl castor oil acid methyl ester 0.3kg), stearic acid emulsion 0.36kg.

[0034] S2 ball mill the alumina powder and deionized water, ball mill parameters include: mass 40kg, speed 35Hz, time 3h.

[0035] S3 sieve and stir the slurry after ball milling, add PVC resin and polyvinyl alcohol solution while stirring; add plasticizer after stirring for 60min; add stearic acid emulsion after stirring for 30min; add oxalic acid to adjust pH to 8 after stirring for 30min; finally stir for another 30min.

[0036] S4 spray granulation treatment of slurry, inlet / outlet temperature 160℃ / 100℃, atomizing disc speed 30Hz; sieve treatment, 45-60um granulation powder.

[0037] S5 granulation powder 130MPa cold isostatic pressing and sintering treatment, obtain super high density alumina ceramic material.

[0038] Example 3

[0039] A method for preparing a super high density alumina ceramic material, comprising the following steps:

[0040] S1 weigh the raw materials as follows: alumina powder 20kg, deionized water 6.67kg, PVC resin 0.14kg, polyvinyl alcohol solution 1kg, plasticizer 0.6kg (acetyl tri(ethylhexyl) citrate 0.3kg, epoxy acetyl castor oil acid methyl ester 0.3kg), stearic acid emulsion 0.36kg.

[0041] S2 ball mill the alumina powder and deionized water, ball mill parameters include: mass 40kg, speed 35Hz, time 3h.

[0042] S3 sieve and stir the slurry after ball milling, and add PVC resin and polyvinyl alcohol solution while stirring; add plasticizer after stirring for 60 min; add stearic acid emulsion after stirring for 30 min; add oxalic acid to adjust pH to 8 after stirring for 30 min; and finally stir for another 30 min.

[0043] S4 spray granulation treatment is performed on the slurry, with inlet / outlet temperature of 160℃ / 100℃ and atomizing disc rotating speed of 30Hz; sieve treatment is performed to obtain granulated powder of 45-60um.

[0044] S5 the granulated powder is subjected to 130MPa cold isostatic pressing and sintering treatment to obtain the ultra-high density alumina ceramic material.

[0045] Example 4

[0046] A preparation method of an ultra-high density alumina ceramic material, comprising the following steps:

[0047] S1 the raw materials are weighed as follows: 20kg of alumina powder, 6.67kg of deionized water, 0.14kg of PVC resin, 1kg of polyvinyl alcohol solution, 0.6kg of plasticizer (0.3kg of acetyl tri (ethylhexyl) citrate and 0.3kg of polyhexamethylene succinate (PHS)), and 0.36kg of stearic acid emulsion.

[0048] S2 ball mill the alumina powder and deionized water, with parameters including mass of 40kg, speed of 35Hz, and time of 3h.

[0049] S3 sieve and stir the slurry after ball milling, and add PVC resin and polyvinyl alcohol solution while stirring; add plasticizer after stirring for 60 min; add stearic acid emulsion after stirring for 30 min; add oxalic acid to adjust pH to 8 after stirring for 30 min; and finally stir for another 30 min.

[0050] S4 spray granulation treatment is performed on the slurry, with inlet / outlet temperature of 160℃ / 100℃ and atomizing disc rotating speed of 30Hz; sieve treatment is performed to obtain granulated powder of 45-60um.

[0051] S5 the granulated powder is subjected to 130MPa cold isostatic pressing and sintering treatment to obtain the ultra-high density alumina ceramic material.

[0052] Example 5

[0053] A preparation method of an ultra-high density alumina ceramic material, comprising the following steps:

[0054] S1 The raw materials are weighed as follows: 20 kg of alumina powder, 6.67 kg of deionized water, 0.14 kg of PVC resin, 1 kg of polyvinyl alcohol solution, 0.6 kg of plasticizer (epoxy acetyl ricinoleic acid methyl ester 0.6 kg), 0.36 kg of stearic acid emulsion.

[0055] S2 The alumina powder and deionized water are ball milled, and the ball milling parameters include: mass 40 kg, speed 35 Hz, and time 3 h.

[0056] S3 The slurry after ball milling is sieved and stirred, and the PVC resin and polyvinyl alcohol solution are added while stirring; the plasticizer is added after stirring for 60 min; the stearic acid emulsion is added after stirring for 30 min; the oxalic acid is added after stirring for 30 min to adjust the pH to 8, and finally stirred for another 30 min.

[0057] S4 The slurry is spray granulated, and the inlet / outlet temperature is 160℃ / 100℃, and the atomizing disc speed is 30 Hz; sieving is performed to obtain granulated powder of 45-60 um.

[0058] S5 The granulated powder is cold isostatic pressed at 130 MPa and sintered to obtain the ultra-high density alumina ceramic material.

[0059] Example 6

[0060] A method for preparing an ultra-high density alumina ceramic material, comprising the following steps:

[0061] S1 The raw materials are weighed as follows: 20 kg of alumina powder, 6.67 kg of deionized water, 0.14 kg of PVC resin, 1 kg of polyvinyl alcohol solution, 0.6 kg of plasticizer (polybutylene succinate 1,6-hexanediol ester (PHS) 0.6 kg), 0.36 kg of stearic acid emulsion.

[0062] S2 The alumina powder and deionized water are ball milled, and the ball milling parameters include: mass 40 kg, speed 35 Hz, and time 3 h.

[0063] S3 The slurry after ball milling is sieved and stirred, and the PVC resin and polyvinyl alcohol solution are added while stirring; the plasticizer is added after stirring for 60 min; the stearic acid emulsion is added after stirring for 30 min; the oxalic acid is added after stirring for 30 min to adjust the pH to 8, and finally stirred for another 30 min.

[0064] S4 The slurry is spray granulated, and the inlet / outlet temperature is 160℃ / 100℃, and the atomizing disc speed is 30 Hz; sieving is performed to obtain granulated powder of 45-60 um.

[0065] S5 The granulated powder is cold isostatic pressed at 130 MPa and sintered to obtain the ultra-high density alumina ceramic material.

[0066] Example 7

[0067] A preparation method of an ultra-high density alumina ceramic material, comprising the following steps:

[0068] S1, the raw materials are weighed as follows: 20 kg of alumina powder, 6.67 kg of deionized water, 0.14 kg of PVC resin, 1 kg of polyvinyl alcohol solution, 0.6 kg of plasticizer (acetyl citric acid tri(ethylhexyl) ester 0.6 kg), and 0.36 kg of stearic acid emulsion.

[0069] S2, the alumina powder and deionized water are ball milled, and the ball milling parameters include: 40 kg of mass, 35 Hz of speed, and 3 h of time.

[0070] S3, the slurry after ball milling is screened and stirred, and the PVC resin and polyvinyl alcohol solution are added while stirring; the plasticizer is added after stirring for 60 min; the stearic acid emulsion is added after stirring for 30 min; the oxalic acid is added after stirring for 30 min to adjust the pH to 8; and finally, the stirring is continued for another 30 min.

[0071] S4, the slurry is subjected to spray granulation treatment, and the inlet / outlet temperature is 160℃ / 100℃, and the rotation speed of the atomizing disc is 30 Hz; the granulation powder is screened to obtain a 45-60um granulation powder.

[0072] S5, the granulation powder is subjected to cold isostatic pressing at 130 MPa and sintering treatment to obtain the ultra-high density alumina ceramic material.

[0073] The densities of the ultra-high density alumina ceramic materials of Examples 1-7 are detected, and the results are as follows:

[0074]

[0075] The results show that, compared with the prior art, the ceramic material body density is greatly improved through the synergistic effect of the ternary plasticizer, which lays a key foundation for the industrial application of high-performance ceramics.

Claims

1. A method for preparing an ultra-high density alumina ceramic material, characterized in that: The steps include: S1 weighs raw materials: alumina powder, deionized water, PVC resin, polyvinyl alcohol solution, plasticizer, stearic acid emulsion; the plasticizer is selected from one or more of acetyl tri(ethylhexyl) citrate, poly(1,6-hexanediol succinate PHS), and epoxy acetylated ricinoleic acid methyl ester; S2 ball-milling alumina powder and deionized water; S3 sieves and stirs the milled slurry, adds PVC resin and polyvinyl alcohol solution while stirring; adds plasticizer after stirring; adds stearic acid emulsion after stirring; adds oxalic acid after stirring to adjust pH, and stirs; S4 spray granulates the slurry and sieves it; The S5 granulated powder is subjected to cold isostatic pressing and sintering to obtain ultra-high density alumina ceramic material.

2. The method for preparing the ultra-high density alumina ceramic material according to claim 1, characterized in that: The plasticizer is selected from two of acetyl tri(ethylhexyl) citrate, poly 1,6-hexanediol succinate (PHS), and epoxy acetyl ricinoleic acid methyl ester.

3. The method for preparing the ultra-high density alumina ceramic material according to claim 2, characterized in that: The plasticizer consists of acetyl tri(ethylhexyl) citrate, poly 1,6-hexanediol succinate (PHS), and epoxy acetyl ricinoleic acid methyl ester.

4. The method for preparing the ultra-high density alumina ceramic material according to claim 3, characterized in that: The plasticizer is composed of acetyl tri(ethylhexyl) citrate, poly 1,6-hexanediol succinate (PHS), and epoxy acetyl ricinoleic acid methyl ester in a mass ratio of 1:1:

1.

5. The method for preparing ultra-high density alumina ceramic material according to claim 1, characterized in that: S1 contains 20 kg of alumina powder, 6.67 kg of deionized water, 0.14 kg of PVC resin, 1 kg of polyvinyl alcohol solution, 0.6 kg of plasticizer, and 0.36 kg of stearic acid emulsion.

6. The method for preparing the ultra-high density alumina ceramic material according to claim 1, characterized in that: The ball milling parameters in S2 include: mass 40 kg, speed 35 Hz, and time 3 h.

7. The method for preparing ultra-high density alumina ceramic material according to claim 1, characterized in that: S3 specifically includes: screening and stirring the ball-milled slurry, adding PVC resin and polyvinyl alcohol solution while stirring; adding plasticizer after stirring for 60 minutes; adding stearic acid emulsion after stirring for 30 minutes; adding oxalic acid after stirring for 30 minutes to adjust the pH to 8, and finally stirring for another 30 minutes.

8. The method for preparing ultra-high density alumina ceramic material according to claim 1, characterized in that: S4 specifically includes: spray granulation treatment of the slurry, with inlet / outlet temperatures of 160°C / 100°C and an atomizing disk speed of 30 Hz; and sieving treatment to obtain granulated powder of 45-60 μm.

9. The method for preparing ultra-high density alumina ceramic material according to claim 1, characterized in that: S5 specifically includes: the granulated powder is subjected to 130MPa cold isostatic pressing and sintering treatment to obtain ultra-high density alumina ceramic material.

10. An ultra-high density alumina ceramic material prepared according to the preparation method according to any one of claims 1 to 9.

Images