A quench-free glass-alumina ceramic powder composite material and its preparation method

Abstract

This invention belongs to the field of low-temperature co-fired ceramics technology, specifically disclosing a low-temperature co-fired ceramic material composed of quench-free glass and alumina ceramic powder, and its preparation method. Unlike common composite materials of quenched glass and alumina ceramic powder, this invention is prepared by mixing glass raw materials and alumina ceramic powder, followed by ball milling, pre-firing, re-ball milling, granulation, sieving, pressing, and sintering. This ceramic material can be sintered at 800-900℃ to obtain a dense glass-ceramic composite. Compared with glass ceramics made from the same quenched raw materials, the quench-free method yields a glass-ceramic material with higher sintering density, thermal conductivity, and flexural strength. Furthermore, the preparation process is simpler and easier, saving energy and manpower. Its superior performance indicates its potential application in LTCC or other electronic ceramic device fields.

Description

Technical Field

[0001] This invention belongs to the field of low-temperature co-fired glass and ceramic technology, specifically relating to a quench-free glass and alumina ceramic powder composite material and its preparation method. Background Technology

[0002] Low-temperature co-fired ceramics (LTCC) is a technology that involves printing interconnects, components, and circuits onto unsintered cast ceramic materials, stacking these structures together, and then sintering them into an integrated multilayer ceramic material. It plays a crucial role in electronic devices. With the explosive growth of mobile devices and the continuous development of communication technologies such as wireless terminal devices towards multifunctionality, high performance, and miniaturization, low-temperature co-fired ceramics are increasingly required to possess higher thermal conductivity and mechanical properties.

[0003] LTCC materials consist of two main components: glass and ceramic. The most widely used LTCC system is the glass-ceramic composite system. This system comprises low-melting-point glass and high-performance ceramic. Glass is typically obtained through high-temperature quenching, which involves mixing glass raw materials, melting and quenching them at high temperatures (usually above 1000℃), and then grinding them into powder using a high-energy ball mill. This process often consumes a large amount of energy and manpower, and even poses a risk of burns to operators. Furthermore, this quenched glass often has an amorphous structure and low thermal conductivity, which is one of the reasons limiting the improvement of the overall thermal conductivity of LTCC. Simultaneously, if the glass does not have good wettability with the ceramic, the sintered sheets will have more porosity, resulting in poor mechanical properties. Summary of the Invention

[0004] To address the aforementioned problems, one objective of this invention is to provide a method for preparing a non-quenching glass-alumina ceramic powder composite material. This method simplifies and enhances the preparation process of low-temperature co-fired ceramics, while simultaneously yielding low-temperature co-fired ceramic materials with excellent thermal conductivity and flexural strength.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a quench-free glass-alumina ceramic powder composite material, comprising the following steps:

[0006] (1) Weigh out the corresponding amount of glass precursor oxides according to the raw material ratio of BBSZA or BBSA glass and mix them to obtain mixed glass raw materials;

[0007] (2) Weigh 100 parts by weight of mixed glass raw material and alumina ceramic powder, of which 30-50 parts by weight are mixed glass raw material, ball mill and dry to obtain a mixture;

[0008] (3) The mixture is pre-fired at 500-700℃ for 1-2 hours. The pre-fired mixture is ball-milled and dried. Then, a binder is added to granulate and sieve the mixture, and then it is pressed into shape.

[0009] (4) The pressed product is sintered at 800-900℃ for 2-4 hours to obtain a quench-free glass and alumina ceramic powder composite material.

[0010] Further improvements to the preparation method of quench-free glass and alumina ceramic powder composite materials:

[0011] Preferably, the raw materials of the BBSZA glass include the following components in molar percentage: 27 mol.% Bi2O3, 26 mol.% B2O3, 15 mol.% SiO2, 27 mol.% ZnO, and 5 mol.% Al2O3.

[0012] Preferably, the mass purity of Bi2O3, SiO2, and Al2O3 is 99.9%, the mass purity of B2O3 is 98%, and the mass purity of ZnO is 99%.

[0013] Preferably, the raw materials for the BBSA glass comprise the following components in molar percentage: 37 mol.% Bi₂O₃, 35.3 mol.% B₂O₃, 20.5 mol.% SiO₂, and 7.2 mol.% Al₂O₃.

[0014] Preferably, the Bi2O3 and SiO2 have a mass purity of 99.9%, the B2O3 has a mass purity of 98%, and the Al2O3 has a mass purity of 99%.

[0015] Preferably, the ball milling time in steps (2) and (3) is 4-6 hours and the drying time is 60-80℃.

[0016] Preferably, the binder in step (3) is a polyvinyl butyral ethanol solution, and the sieve is a 100-mesh sieve.

[0017] Preferably, the pressing pressure in step (3) is 25-50 MPa and the forming diameter is 25.5 mm.

[0018] Preferably, in step (4), the temperature is increased to the sintering temperature at a heating rate of 4°C / min.

[0019] The second objective of this invention is to provide a quench-free glass and alumina ceramic powder composite material prepared by any of the above-mentioned methods.

[0020] The advantages of this invention compared to the prior art are as follows:

[0021] This invention provides a method for preparing a quench-free glass-alumina ceramic powder composite material. The method uses a quench-free process to obtain a mixture of glass and ceramic raw materials. The process is simple and safe, saves energy and manpower, avoids the dangers of high-temperature quenching, and is suitable for factory production.

[0022] Unlike existing quenching methods, the quench-free method of this invention involves directly mixing and pre-firing the glass raw material with ceramic powder. During pre-firing, the zinc oxide and alumina ceramic grains in the glass raw material react to form zinc aluminate. The early formation of zinc aluminate grains not only increases the grain boundary energy of the system but also reduces the porosity between alumina particles, which is beneficial for the densification of the final sintered sheet. In contrast, the quenching method involves mixing quenched amorphous glass powder with ceramic powder, resulting in the formation of zinc aluminate crystals during the mid-sintering stage. Liquid phase flow begins in the mid-sintering stage, and the zinc aluminate grains formed at this point hinder the flow of the liquid phase, preventing the filling of large pores and reducing the sintering density of the system.

[0023] The difference in sintering density of the system results in the quench-free BBSZA / Al2O3 composite glass-ceramic material prepared in this invention having superior thermal conductivity and flexural strength compared to the quenching method. The thermal conductivity is 5.352-6.319 W / mK, and the tensile strength is 107.48-193.54 MPa, which has great application prospects in the field of electronic packaging. Attached Figure Description

[0024] Figure 1 This is a cross-sectional scanning electron microscope image of a sintered sheet with a BBSZA non-quenching glass content of 50 wt.% prepared in Example 1 of the present invention.

[0025] Figure 2 This is a cross-sectional scanning electron microscope image of the sintered sheet with a BBSZA quenched glass content of 50 wt.% prepared in Comparative Example 1 of the present invention.

[0026] Figure 3 This is a cross-sectional scanning electron microscope image of a sintered sheet with a BBSA non-quenching glass content of 50 wt.% prepared in Example 2 of the present invention.

[0027] Figure 4 This is a cross-sectional scanning electron microscope image of the sintered sheet with a BBSA quenched glass content of 50 wt.% prepared in Comparative Example 2 of the present invention.

[0028] Figure 5 The XRD results are for the pre-fired powder of BBSZA non-quenching glass with a content of 50 wt.% obtained in Example 1 of this invention.

[0029] Figure 6 The XRD results are for the BBSA non-quenched glass powder with a content of 50 wt.% obtained in Example 2 of this invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. 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.

[0031] Example 1

[0032] This embodiment provides a method for preparing a quench-free glass-alumina ceramic powder composite material, which specifically includes the following steps:

[0033] (1) According to the raw material ratio of BBSZA glass, weigh 27 mol.% Bi2O3 (purity 99.9%), 26 mol.% B2O3 (purity 98%), 15 mol.% SiO2 (purity 99.9%), 27 mol.% ZnO (purity 99%) and 5 mol.% Al2O3 (purity 99.9%) and mix them to obtain mixed glass raw materials;

[0034] (2) Divide the mixed glass raw material into five equal parts and mix them with alumina ceramic powder in the following mass ratios: 30 parts mixed glass raw material + 70 parts alumina ceramic powder, 35 parts mixed glass raw material + 65 parts alumina ceramic powder, 40 parts mixed glass raw material + 60 parts alumina ceramic powder, 45 parts mixed glass raw material + 55 parts alumina ceramic powder, and 50 parts mixed glass raw material + 50 parts alumina ceramic powder. Ball mill the mixtures separately. The ball milling medium is deionized water. The ball mill speed is 360 r / min and the ball milling time is 4 h. Then dry them in an oven at 60 ℃ to obtain mixtures 1-5.

[0035] (3) Mixtures 1-5 were placed in a muffle furnace for pre-calcination. The heating rate was 4℃ / min, the pre-calcination temperature was 600℃, and the holding time was 1h. After pre-calcination, the powder was placed in a ball mill for ball milling. The ball milling medium was deionized water, the ball milling time was 4h, and the ball mill speed was 350r / min. After ball milling, the powder was placed in an 80℃ oven for drying to obtain dried powders 1-5.

[0036] (4) Add equal amounts of polyvinyl butyral ethanol solution to the dried powders 1-5 respectively, mix them, grind and granulate them in a mortar, grind them evenly, pass them through a 100-mesh sieve, put them into a cylindrical mold with a diameter of 25.5 mm, and press them under a pressure of 25 MPa to obtain the molded samples 1-5.

[0037] (5) Place the molded samples 1-5 into a muffle furnace, heat them at a rate of 4℃ / min, and sinter them at 900℃ for 2 hours to obtain the quench-free glass and alumina ceramic powder composite material 1-5.

[0038] Comparative Example 1

[0039] This comparative example provides a method for preparing a composite material of quenched glass and alumina ceramic powder, specifically including the following steps:

[0040] (1) According to the raw material ratio of BBSZA glass, weigh 27 mol.% Bi2O3 (purity 99.9%), 26 mol.% B2O3 (purity 98%), 15 mol.% SiO2 (purity 99.9%), 27 mol.% ZnO (purity 99%) and 5 mol.% Al2O3 (purity 99.9%) and mix them to obtain mixed glass raw materials;

[0041] (2) The mixed glass raw materials were ball-milled for 4 hours, dried in an oven at 60°C, heated to 1100°C in a resistance furnace at a heating rate of 5°C / min, and kept at that temperature for 2 hours. Then the raw materials were immediately taken out and poured into deionized water for quenching. After quenching, the powder was ball-milled for 16 hours at a ball-milling rate of 350 r / min to obtain the ball-milled glass raw materials.

[0042] (3) Divide the ball-ground glass raw material into five equal parts and mix it with alumina ceramic powder in the following mass ratios: 30 parts ball-ground glass raw material + 70 parts alumina ceramic powder, 35 parts ball-ground glass raw material + 65 parts alumina ceramic powder, 40 parts ball-ground glass raw material + 60 parts alumina ceramic powder, 45 parts ball-ground glass raw material + 55 parts alumina ceramic powder, and 50 parts ball-ground glass raw material + 50 parts alumina ceramic powder. Ball-mill the mixture separately. The ball-milling medium is deionized water. The ball mill speed is 360 r / min and the ball milling time is 4 h. Then place it in an oven at 60 ℃ to dry, and obtain dried powder 6-10 respectively.

[0043] (4) Add equal amounts of polyvinyl butyral ethanol solution to the dried powder 6-10, mix and grind in a mortar to form granules. After grinding evenly, pass through a 100-mesh sieve and place into a cylindrical mold with a diameter of 25.5 mm. Press and mold under a pressure of 25 MPa to obtain the molded sample 6-10.

[0044] (5) Place the molded samples 6-10 into a muffle furnace, heat them at a rate of 4℃ / min, and sinter them at 900℃ for 2 hours to obtain the quenched glass and alumina ceramic powder composite material 6-10.

[0045] The density, thermal conductivity, shrinkage rate, and tensile strength of the five non-quenched glass-ceramic composite materials with different proportions prepared in Example 1 and the five quenched glass-ceramic composite materials with different proportions prepared in Comparative Example 1 are shown in Table 1 below.

[0046] Table 1 Performance tests of composite materials in Example 1 and Comparative Example 1

[0047]

[0048]

[0049] As shown in Table 1, under the same BBSZA glass content, the thermal conductivity and bending strength of the BBSZA / Al2O3 sintered sheet obtained by the non-quenching method are higher than those obtained by the quenching method.

[0050] Example 2

[0051] This embodiment provides a method for preparing a quench-free glass-alumina ceramic powder composite material, which specifically includes the following steps:

[0052] (1) According to the raw material ratio of BBSA glass, weigh 37 mol.% Bi2O3 (purity 99.9%), 35.3 mol.% B2O3 (purity 98%), 20.5 mol.% SiO2 (purity 99.9%), and 7.2 mol.% Al2O3 (purity 99%) and mix them to obtain mixed glass raw materials;

[0053] (2) Mix the mixed glass raw material and alumina ceramic powder at a mass ratio of 50 parts mixed glass raw material + 50 parts alumina ceramic powder, and ball mill the mixture. The ball milling medium is deionized water, the ball mill speed is 360 r / min, the ball milling time is 4 h, and then the mixture is dried in an oven at 60 ℃ to obtain mixture 11.

[0054] (3) The mixture 11 was placed in a muffle furnace for pre-calcination. The heating rate was 4℃ / min, the pre-calcination temperature was 600℃, and the holding time was 1h. After the pre-calcination, the powder was placed in a ball mill for ball milling. The ball milling medium was deionized water, the ball milling time was 4h, and the ball mill speed was 350r / min. After ball milling, the powder was placed in an 80℃ oven for drying to obtain dried powder 11.

[0055] (4) Add an equal amount of polyvinyl butyral ethanol solution to the dried powder 11, mix and grind in a mortar to form granules. After grinding evenly, pass through a 100-mesh sieve and place into a cylindrical mold with a diameter of 25.5 mm. Press and mold under a pressure of 25 MPa to obtain the molded sample 11.

[0056] (5) Place the molded sample 11 into a muffle furnace, heat it at a rate of 4℃ / min, and sinter it at 900℃ for 2 hours to obtain the quench-free glass and alumina ceramic powder composite material 11.

[0057] The thermal conductivity of the prepared quench-free glass-ceramic composite material was tested to be 6.482 W / mK, and XRD results also showed that Bi4Si3O was produced in the pre-sintered powder. 12 Crystal.

[0058] Comparative Example 2

[0059] This comparative example provides a method for preparing a composite material of quenched glass and alumina ceramic powder, specifically including the following steps:

[0060] (1) According to the raw material ratio of BBSA glass, weigh 37 mol.% Bi2O3 (purity 99.9%), 35.3 mol.% B2O3 (purity 98%), 20.5 mol.% SiO2 (purity 99.9%), and 7.2 mol.% Al2O3 (purity 99%) and mix them to obtain mixed glass raw materials;

[0061] (2) The mixed glass raw materials were ball-milled for 4 hours, dried in an oven at 60°C, heated to 1100°C in a resistance furnace at a heating rate of 5°C / min, and kept at that temperature for 2 hours. Then the raw materials were immediately taken out and poured into deionized water for quenching. After quenching, the powder was ball-milled for 16 hours at a ball-milling rate of 350 r / min to obtain the ball-milled glass raw materials.

[0062] (3) Mix the ball-milled glass raw material and alumina ceramic powder at a mass ratio of 50 parts mixed glass raw material + 50 parts alumina ceramic powder, ball-mill the mixture, use deionized water as the ball milling medium, the ball mill speed is 360 r / min, the ball milling time is 4 h, and then put it into an oven at 60℃ to dry, to obtain dried powder 12.

[0063] (4) Add an equal amount of polyvinyl butyral ethanol solution to the dried powder 12, mix and grind in a mortar to form granules. After grinding evenly, pass through a 100-mesh sieve and place into a cylindrical mold with a diameter of 25.5 mm. Press and mold under a pressure of 25 MPa to obtain the molded sample 12.

[0064] (5) Place the molded sample 12 into a muffle furnace, heat it at a rate of 4℃ / min, and sinter it at 900℃ for 2 hours to obtain the quenched glass and alumina ceramic powder composite material 12.

[0065] The thermal conductivity of the quench-free glass-ceramic composite material prepared above was tested to be 5.485 W / mK. The thermal conductivity of the BBSA / Al2O3 sintered sheet obtained by the quenching method is nearly 1 W / mK lower than that obtained by the quench-free method.

[0066] Figure 1-4 The images shown are cross-sectional scanning electron microscope (SEM) images of sintered sheets with a glass content of 50 wt.% prepared in Examples 1, 1, 2, and 2 of this invention, respectively. Figure 1-4 The test results show that the BBSZA / Al2O3 and BBSA / Al2O3 ceramic sheets obtained by the quench-free method have a denser microstructure, smaller porosity, and smaller pore size than the sintered sheets obtained by the quenching method. This is also the direct reason why the sintered sheets obtained by the quench-free method have better thermal conductivity and mechanical properties. Figure 5-6 The images shown are XRD patterns of the pre-calcined powders from Examples 1 and 2 of this invention, respectively. Figure 5-6 It is known that both types of glass powder underwent chemical reactions during the pre-firing process, leading to the formation of new crystals. The premature formation of crystals has a significant impact on the subsequent sintering process. The quench-free methods in Examples 1 and 2 can obtain sintered sheets with higher density and lower porosity. In addition, regardless of whether it is the quenching method or the quench-free method, the thermal conductivity of the sintered sheet shows a decreasing trend with the increase of glass content, because the thermal conductivity of glass is much lower than that of ceramics.

[0067] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for preparing a quench-free glass-alumina ceramic powder composite material, characterized in that, Includes the following steps: (1) Weigh out the corresponding amount of glass precursor oxides according to the raw material ratio of BBSZA glass or BBSA glass and mix them to obtain mixed glass raw materials; the raw materials of BBSZA glass include Bi2O3, B2O3, SiO2, ZnO and Al2O3; the raw materials of BBSA glass include Bi2O3, B2O3, SiO2 and Al2O3. (2) Weigh 100 parts by weight of mixed glass raw material and alumina ceramic powder, of which 30-50 parts by weight of mixed glass raw material are ball-milled and dried to obtain a mixture; (3) The mixture is pre-fired at 500-700℃ for 1-2 hours. The pre-fired mixture is ball-milled and dried. Then, a binder is added to granulate and sieve the mixture, and then it is pressed into shape. (4) The pressed product is sintered at 800-900℃ for 2-4 hours to obtain a quench-free glass and alumina ceramic powder composite material.

2. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, The raw materials of the BBSZA glass include the following components in molar percentage: 27 mol% Bi2O3, 26 mol% B2O3, 15 mol% SiO2, 27 mol% ZnO, and 5 mol% Al2O3.

3. The preparation method of the non-quenching glass and alumina ceramic powder composite material according to claim 2, characterized in that, The mass purity of Bi2O3, SiO2, and Al2O3 is 99.9%, the mass purity of B2O3 is 98%, and the mass purity of ZnO is 99%.

4. The preparation method of the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, The raw materials for the BBSA glass include the following components in molar percentage: 37 mol% Bi2O3, 35.3 mol% B2O3, 20.5 mol% SiO2, and 7.2 mol% Al2O3.

5. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 4, characterized in that, The Bi2O3 and SiO2 have a mass purity of 99.9%, the B2O3 has a mass purity of 98%, and the Al2O3 has a mass purity of 99%.

6. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, The ball milling time in steps (2) and (3) is 4-6 hours, and the drying temperature is 60-80℃.

7. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, The binder in step (3) is a polyvinyl butyral ethanol solution, which is sieved through a 100-mesh sieve.

8. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, In step (3), the pressing pressure is 25-50 MPa and the forming diameter is 25.5 mm.

9. The method for preparing the non-quenching glass and alumina ceramic powder composite material according to claim 1, characterized in that, In step (4), the temperature is increased to the sintering temperature at a heating rate of 4℃ / min.

10. A quench-free glass and alumina ceramic powder composite material prepared by the preparation method of any one of claims 1-9.

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