Barium-calcium-aluminum-silicon microcrystalline glass material and preparation method thereof

Abstract

The invention belongs to the technical field of electronic ceramic materials, and particularly relates to a barium-calcium-aluminum-silicon microcrystalline glass material and a preparation method thereof. The invention provides a barium-calcium-aluminum-silicon glass ceramic material. The barium-calcium-aluminum-silicon glass ceramic material is prepared from the following preparation raw materials in molar content: 30 to 50 mol percent of BaCO3, 1 to 10 mol percent of CaCO3, 10 to 25 mol percent of Al2O3 and 30 to 55 mol percent of SiO2. According to the barium-calcium-aluminum-silicon series glass ceramic material and the preparation method thereof, the four raw materials including BaCO3, CaCO3, Al2O3 and SiO2 are compounded, meanwhile, the molar ratio of the four raw materials is optimized, the content of all components in the glass ceramic can be well optimized, and the obtained barium-calcium-aluminum-silicon series glass ceramic material has the advantages of being high in dielectric constant, high in frequency and low in loss.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic ceramic materials, and particularly relates to a barium calcium aluminum silicon-based glass-ceramic material and a preparation method thereof. Background Art

[0002] In the field of electronic engineering, the dielectric constant (Dk) is a key parameter for measuring the ability of a material to store energy in an electric field. A board with a dielectric constant of about 10 represents a type of material with relatively high dielectric properties. The above-mentioned board is particularly important in high-frequency applications, capable of providing faster signal transmission speeds and higher characteristic impedances, and is widely used in multiple fields such as aerospace, radar detection, satellite communication, and electronic packaging.

[0003] Currently, widely used electronic ceramic substrates include the glass-ceramic CaO-B2O3-SiO2 system A6 product (dielectric constant of 5.7) of "vibrantz technologies" company and the glass / ceramic composite system 951 product (dielectric constant of 7.8) of DuPont company. However, the dielectric constants of the above two products are still relatively low, which limits their wide application. Materials with a dielectric constant of about 10 are mainly organic materials and organic / ceramic composites currently widely used. However, with higher requirements for the thermal stability and durability of materials, neither organic materials nor organic / ceramic composites can well meet the requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a barium calcium aluminum silicon-based glass-ceramic material and a preparation method thereof. The barium calcium aluminum silicon-based glass-ceramic material provided by the present invention has a high dielectric constant and high-frequency low-loss characteristics, and at the same time has excellent thermal stability and durability.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a barium calcium aluminum silicon-based glass-ceramic material, including the following raw materials for preparation in molar content:

[0007] BaCO3 30 - 50 mol%, CaCO3 1 - 10 mol%, Al2O3 10 - 25 mol%, SiO2 30 - 55 mol%.

[0008] Preferably, the dielectric constant of the barium calcium aluminum silicon-based glass-ceramic material in the range of 5 - 20 GHz is 9.07 - 10.22, and the dielectric loss < 2×10 -3 .

[0009] The present invention provides a preparation method of the barium calcium aluminum silicon-based glass-ceramic material described in the above technical solution, including the following steps:

[0010] Mix BaCO3, CaCO3, Al2O3 and SiO2 and heat them to melt, obtaining a molten glass liquid;

[0011] Quench the molten glass liquid with water to obtain a vitreous body;

[0012] Grind the vitreous body to obtain glass powder;

[0013] Age, screen and granulate the glass powder in sequence to obtain granular material;

[0014] Press the granular material to form a green body;

[0015] Heat-treat the green body to obtain the barium-calcium-aluminum-silicon system glass-ceramics material.

[0016] Preferably, the temperature for heating and melting is 1200 - 1450 °C, and the heat preservation time is 2 - 4 h.

[0017] Preferably, the grinding is wet ball milling; the rotation speed of the wet ball milling is 300 - 450 rpm, and the time is 6 - 12 h.

[0018] Preferably, the wet ball milling obtains ball-milled material, and it further includes screening the ball-milled material, taking the undersize and drying it to obtain the glass powder, and the screen mesh for screening is 500 meshes.

[0019] Preferably, the reagent used for aging is polyvinyl alcohol; the mass ratio of the glass powder to the polyvinyl alcohol is 50:1 - 2.

[0020] Preferably, the polyvinyl alcohol is used in the form of an aqueous solution of polyvinyl alcohol, and the mass content of polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is 2 - 5%.

[0021] Preferably, the pressure for pressing and forming is 50 - 100 MPa.

[0022] Preferably, the temperature for heat treatment is 1150 - 1350 °C, and the heat preservation time is 30 - 40 min; the heating rate for rising to the temperature of the heat treatment is 5 - 10 °C / min.

[0023] The present invention provides a barium-calcium-aluminum-silicate system glass-ceramic material, comprising raw materials for preparation with the following molar contents: 30-50 mol% of BaCO3, 1-10 mol% of CaCO3, 10-25 mol% of Al2O3, and 30-55 mol% of SiO2. The present invention uses four raw materials, namely BaCO3, CaCO3, Al2O3, and SiO2, in combination, and simultaneously optimizes the molar ratio of the four raw materials, which can well optimize the contents of various components in the glass-ceramic. The obtained barium-calcium-aluminum-silicate system glass-ceramic material (BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic material) has the characteristics of high dielectric constant and low loss at high frequency. At the same time, compared with organic materials and organic / ceramic composite materials, the glass-ceramic material provided by the present invention has high crystal phase stability, excellent thermal stability and durability.

[0024] Further, in the present invention, the dielectric constant of the barium-calcium-aluminum-silicate system glass-ceramic material in the range of 5-20 GHz is 9.07-10.22, and the dielectric loss < 2×10 -3 . The dielectric constant of the barium-calcium-aluminum-silicate system glass-ceramic material provided by the present invention is 9.07-10.22 (5-20 GHz), meeting the requirement of a dielectric constant of about 10; at the same time, the dielectric loss < 2×10 -3 .

[0025] The present invention provides a preparation method of the barium-calcium-aluminum-silicate system glass-ceramic material described in the above technical solution, comprising the following steps: mixing BaCO3, CaCO3, Al2O3, and SiO2 and heating to melt to obtain a molten glass liquid; quenching the molten glass liquid with water to obtain a glass body; grinding the glass body to obtain glass powder; aging, screening, and granulating the glass powder in sequence to obtain granular material; pressing the granular material into a green body; and performing heat treatment on the green body to obtain the barium-calcium-aluminum-silicate system glass-ceramic material. The present invention uses the melting and water quenching method to prepare glass powder, and then prepares glass-ceramic from the glass powder. The preparation method provided by the present invention is simple and easy to operate, low in cost, stable in process, and suitable for industrial production. Description of the Drawings

[0026] Figure 1 XRD patterns of the BaCO3-CaCO3-Al2O3-SiO2 glass powder prepared in Examples 1-4;

[0027] Figure 2 DSC curves of the BaCO3-CaCO3-Al2O3-SiO2 glass powder prepared in Examples 1-4 under the condition of 5 °C / min;

[0028] Figure 3Infrared curve graphs of the BaCO3-CaCO3-Al2O3-SiO2 glass powder prepared in Examples 1 to 4;

[0029] Figure 4 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic product obtained after heat treatment of Example 1;

[0030] Figure 5 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic product obtained after heat treatment of Example 2;

[0031] Figure 6 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic product obtained after heat treatment of Example 3;

[0032] Figure 7 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic product obtained after heat treatment of Example 4. Detailed implementation manners

[0033] The present invention provides a barium-calcium-aluminum-silicon glass-ceramic material, which comprises preparation raw materials with the following molar contents:

[0034] BaCO3 30 to 50 mol%, CaCO3 1 to 10 mol%, Al2O3 10 to 25 mol%, SiO2 30 to 55 mol%.

[0035] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well-known to those skilled in the art.

[0036] In terms of molar content, the preparation raw materials of the barium-calcium-aluminum-silicon glass-ceramic material provided by the present invention include 30 to 50 mol% of BaCO3, and in the examples, it can be 50 mol%, 40 mol% or 30 mol%.

[0037] In terms of molar content, the preparation raw materials of the barium-calcium-aluminum-silicon glass-ceramic material provided by the present invention include 1 to 10 mol% of CaCO3, and in the examples, it can be 5 mol%, 10 mol%, 3 mol% or 1 mol%.

[0038] In terms of molar content, the preparation raw materials of the barium-calcium-aluminum-silicon glass-ceramic material provided by the present invention include 10 to 25 mol% of Al2O3, and in the examples, it can be 15 mol%, 10 mol%, 12 mol% or 25 mol%.

[0039] In terms of molar content, the raw materials for preparing the barium-calcium-aluminum-silicate-based glass-ceramic material provided by the present invention include 30-55 mol% of SiO2, which can be 30 mol%, 40 mol%, 44 mol% or 55 mol% in the examples.

[0040] The present invention controls the molar content ratio of the raw materials as follows: 30-50 mol% of BaCO3, 1-10 mol% of CaCO3, 10-25 mol% of Al2O3, and 30-55 mol% of SiO2. The obtained barium-calcium-aluminum-silicate-based glass-ceramic material has the characteristics of high dielectric constant, high-frequency low loss, and high crystal phase stability.

[0041] In the present invention, the dielectric constant of the barium-calcium-aluminum-silicate-based glass-ceramic material in the range of 5-20 GHz is 9.07-10.22, and the dielectric loss < 2×10 -3 .

[0042] The present invention provides a method for preparing the barium-calcium-aluminum-silicate-based glass-ceramic material according to the above technical solution, including the following steps:

[0043] Mix BaCO3, CaCO3, Al2O3 and SiO2 and heat them to melt to obtain a molten glass liquid;

[0044] Quench the molten glass liquid with water to obtain a glass body;

[0045] Grind the glass body to obtain glass powder;

[0046] Age, screen and granulate the glass powder in sequence to obtain granular material;

[0047] Press the granular material into a green body;

[0048] Heat-treat the green body to obtain the barium-calcium-aluminum-silicate-based glass-ceramic material.

[0049] The present invention mixes BaCO3, CaCO3, Al2O3 and SiO2 and heats them to melt to obtain a molten glass liquid. In the present invention, the heating and melting are carried out in an electric resistance furnace. The temperature of the heating and melting is preferably 1200-1450 °C, more preferably 1300-1350 °C, which can be 1400 °C in the examples; the heat preservation time is preferably 2-4 h, which can be 3 h in the examples. The heating and melting are preferably carried out in an air atmosphere.

[0050] After obtaining the molten glass liquid, the present invention quenches the molten glass liquid with water to obtain a vitreous body. In the present invention, the water quenching is preferably to pour the molten glass liquid into water so that the molten glass liquid is rapidly quenched to form a vitreous body. The water is preferably deionized water, and the temperature of the water is preferably 20 to 30 °C, and can be 25 °C in the examples.

[0051] After obtaining the vitreous body, the present invention grinds the vitreous body to obtain glass powder. In the present invention, the grinding is preferably wet ball milling. The wet ball milling is preferably carried out in a planetary ball mill. The medium for the wet ball milling is preferably water, and the water is preferably deionized water. The wet ball milling preferably uses grinding balls, and the grinding balls are preferably zirconium balls. The particle size of the grinding balls is preferably 0.1 to 10 mm. The ball-to-material ratio for the wet ball milling is preferably 2 to 5:1. The ball-to-material ratio is the mass ratio of the grinding balls to the vitreous body. The liquid-to-solid ratio for the wet ball milling is preferably 1.5 to 2.5:1. The liquid-to-solid ratio is the ratio of the volume (unit: mL) of the medium for the wet ball milling to the mass (unit: g) of the vitreous body. The rotation speed of the wet ball milling is preferably 300 to 450 rpm, and can be 400 rpm in the examples, and the time is preferably 6 to 12 h, and can be 10 h in the examples.

[0052] In the present invention, the wet ball milling preferably obtains a ball-milled material. The present invention preferably further includes screening the ball-milled material, taking the undersize and drying it to obtain the glass powder. The screen mesh for the screening is preferably 500 meshes. The drying is preferably drying in an oven, and the present invention has no special requirements for the specific implementation manner of the drying in an oven.

[0053] In the present invention, the glass powder is a glass powder with a high softening point. The glass powder prepared by the present invention preferably has no obvious crystal phase formation. The softening point T of the glass powder g is preferably > 880 °C.

[0054] After obtaining the glass powder, the present invention ages, screens and granulates the glass powder in sequence to obtain a granular material. In the present invention, the reagent used for aging is preferably polyvinyl alcohol (PVA); the mass ratio of the glass powder to the polyvinyl alcohol is preferably 50:1 to 2. When aging, the polyvinyl alcohol is preferably used in the form of an aqueous polyvinyl alcohol solution, and the mass content of polyvinyl alcohol in the aqueous polyvinyl alcohol solution is preferably 2 to 5 wt%, and can be 4 wt% in the examples. The aging is preferably: adding the aqueous polyvinyl alcohol solution to the glass powder and mixing, and the addition method of the aqueous polyvinyl alcohol solution is preferably adding in batches.

[0055] In the present invention, the screen mesh used for screening is preferably 200 meshes. The particle size of the granular material is preferably ≤ 0.074 mm.

[0056] After obtaining the granular material, the present invention compresses the granular material into a green body. In the present invention, the compression molding is carried out in a press. The pressure of the compression molding is preferably 50-100 MPa, and can be 60 MPa in the examples. The size of the green body is preferably Φ10 mm × 2 mm.

[0057] After obtaining the green body, the present invention heat-treats the green body to obtain the barium-calcium-aluminum-silicate microcrystalline glass material. In the present invention, the heat treatment is preferably carried out in an electric resistance furnace. The heat treatment is preferably carried out in an air atmosphere. The temperature of the heat treatment is preferably 1150-1350 °C, and can be 1200 °C in the examples. The heat preservation time is preferably 10-60 min, and can be 30 min in the examples; the heating rate for heating to the temperature of the heat treatment is preferably 5-10 °C / min, and can be 5 °C / min in the examples. The heat treatment is preferably carried out in an air atmosphere. In the present invention, after the heat treatment is completed, the present invention preferably cools the product obtained by the heat treatment in the furnace to obtain the barium-calcium-aluminum-silicate microcrystalline glass material.

[0058] In the present invention, during the heat treatment process, BaO obtained by the decomposition of BaCO3 forms barium aluminate (such as BaAl2O4) with Al2O3, and the dielectric constant is relatively high (about 10), which improves the overall dielectric constant. CaO obtained by the decomposition of CaCO3 is an external network body, which reduces the sintering temperature and promotes densification; it forms calcium silicate glass phase with SiO2, fills the grain boundaries and reduces pores. It also forms crystal phases with Al2O3 and SiO2 to regulate the dielectric properties. SiO2 is a glass network former, which enables the raw materials to be melted into glass and forms crystal phases with BaO, CaO and Al2O3. Because the crystal phase has low dielectric loss and the sample has high densification, it has low dielectric loss.

[0059] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with examples, but they should not be construed as limiting the protection scope of the present invention.

[0060] Example 1

[0061] This example provides a BaCO3-CaCO3-Al2O3-SiO2 microcrystalline glass, and the types of its preparation raw materials and the molar contents of each preparation raw material are shown in Table 1.

[0062] Table 1 Formulations, heat treatment temperatures, softening temperatures and dielectric properties of BaCO3-CaCO3-Al2O3-SiO2 microcrystalline glasses provided in Examples 1-4

[0063]

[0064] The preparation method of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramics provided by this embodiment specifically includes the following steps:

[0065] (1) Preparation of glass powder by the melting and water quenching method:

[0066] According to the molar contents shown in Table 1, BaCO3, CaCO3, Al2O3, and SiO2 are fully mixed, and then heated to 1400 °C in an electric resistance furnace and kept warm for 3 h to obtain a molten glass liquid. Then, the molten glass liquid is poured into deionized water (25 °C) to be rapidly quenched to form a glass body. The glass body is placed in a planetary ball mill for wet grinding. The ball milling medium is deionized water, the grinding balls are zirconium balls (particle size is 1 mm), the ball-to-material ratio is 3:1, the liquid-to-solid ratio of wet ball milling is 2.5:1, the rotation speed of the ball mill is 400 rpm, and the ball milling time is 10 h. The ball-milled material is sieved through a 500-mesh sieve, and the material under the sieve is taken and dried to obtain a high softening point glass powder (BaCO3-CaCO3-Al2O3-SiO2 glass powder).

[0067] (2) Preparation of BaCO3-CaCO3-Al2O3-SiO2 glass-ceramics:

[0068] Polyvinyl alcohol (PVA) aqueous solution (4 wt%) is added to the high softening point glass powder in batches, and then the mixture is aged (the mass ratio of the high softening point glass powder to polyvinyl alcohol is 50:1), sieved (200 mesh), and granulated in sequence. The particle size of the obtained granular material is ≤ 0.074 mm, and it is pressed into a green body with a size of Φ10 mm × 2 mm under a pressure of 60 MPa by mechanical pressing. The green body is placed in an electric resistance furnace and heated to 1200 °C at a heating rate of 5 °C / min, kept warm for 30 min, and then cooled with the furnace to obtain a barium-calcium-aluminum-silicon-based high softening temperature glass-ceramics material.

[0069] Examples 2 to 4:

[0070] Examples 2 to 4 provide a BaCO3-CaCO3-Al2O3-SiO2 glass-ceramics, and the preparation raw materials and the molar contents of each preparation raw material are shown in Table 1.

[0071] The preparation method of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramics provided by Examples 2 to 4 is the same as that of Example 1, except that the molar ratio of the raw materials is carried out according to Table 1, and the heat treatment temperature is carried out according to Table 1.

[0072] Figure 1 XRD patterns of the BaCO3-CaCO3-Al2O3-SiO2 glass powder prepared for Examples 1 to 4. From Figure 1 It can be seen that the XRD spectra of the BaCO3-CaCO3-Al2O3-SiO2 glass powder prepared for Examples 1 to 4 are all broad hump-shaped peaks, and there are no obvious crystal phases.

[0073] Figure 2 DSC curves of the BaCO3-CaCO3-Al2O3-SiO2 glass powders prepared in Examples 1 to 4 under the condition of 5 °C / min. The results show that the BaCO3-CaCO3-Al2O3-SiO2 glass powders prepared in Examples 1 to 4 have a relatively high softening point temperature.

[0074] Figure 3 Infrared curves of the BaCO3-CaCO3-Al2O3-SiO2 glass powders prepared in Examples 1 to 4.

[0075] Figure 4 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products obtained after heat treatment of Example 1. Figure 5 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products obtained after heat treatment of Example 2. Figure 6 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products obtained after heat treatment of Example 3. Figure 7 SEM images of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products obtained after heat treatment of Example 4. Figures 4 to 7 It shows that the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products of Examples 1 to 6 of the present invention are successfully prepared.

[0076] Comparative Examples 1 to 2:

[0077] Comparative Examples 1 to 2 provide a glass-ceramic, and the preparation raw materials and the molar contents of each preparation raw material are shown in Table 2.

[0078] Table 2 Glass-ceramic formula, heat treatment temperature, softening temperature and dielectric properties provided by Comparative Examples 1 to 2

[0079]

[0080]

[0081] The preparation method of the glass-ceramic provided by Comparative Examples 1 to 2 is the same as that of Example 1, except that the molar ratio of the raw materials is carried out according to Table 2. The heat treatment temperature is carried out according to Table 2.

[0082] From the dielectric constant (5 - 20 GHz) and dielectric loss data of the products in Table 1 and Table 2, it can be seen that the dielectric constant (5 - 20 GHz) and dielectric loss of the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic products prepared in Examples 1 to 4 are significantly more excellent than the performance of the glass products prepared by Comparative Examples 1 to 2.

[0083] As can be seen from the above embodiments, the present invention provides a barium-calcium-aluminum-silicate system glass-ceramic material, comprising raw materials for preparation with the following molar contents: BaCO3 30-50 mol%, CaCO3 1-10 mol%, Al2O3 10-25 mol%, SiO2 30-55 mol%. The present invention uses four raw materials, BaCO3, CaCO3, Al2O3 and SiO2, in combination, and at the same time optimizes the molar ratio of the four raw materials, which can well optimize the contents of each component in the glass-ceramic. The obtained barium-calcium-aluminum-silicate system glass-ceramic material (BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic material) has the characteristics of high dielectric constant and high-frequency low loss. At the same time, the BaCO3-CaCO3-Al2O3-SiO2 glass-ceramic material provided by the present invention has high crystal phase stability.

[0084] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, rather than all the embodiments. Other embodiments can also be obtained according to these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A barium-calcium-aluminum-silicate-based glass-ceramic material, characterized in that, The preparation raw materials include the following molar contents: BaCO3 30 - 50 mol%, CaCO3 1 - 10 mol%, Al2O3 10 - 25 mol%, SiO2 30 - 55 mol%.

2. The barium-calcium-aluminum-silicon-based glass-ceramic material according to claim 1, wherein The dielectric constant of the barium-calcium-aluminum-silicon-based glass-ceramic material is 9.07 to 10.22 in the range of 5 to 20 GHz, and the dielectric loss < 2×10 -3 .

3. The preparation method of the barium calcium aluminum silicon-based glass-ceramic material according to claim 1 or 2, characterized in that, It includes the following steps: Mix BaCO3, CaCO3, Al2O3 and SiO2 and heat them to melt to obtain a molten glass liquid; Quench the molten glass liquid with water to obtain a glass body; Grind the glass body to obtain glass powder; Age, screen and granulate the glass powder in sequence to obtain granular materials; Press the granular materials into shape to obtain a green body; Perform heat treatment on the green body to obtain the barium calcium aluminum silicon system glass-ceramic material.

4. The preparation method according to claim 3, characterized in that, The temperature of the heating and melting is 1200 - 1450 °C, and the heat preservation time is 2 - 4 h.

5. The preparation method according to claim 3, characterized in that, The grinding is wet ball milling; the rotation speed of the wet ball milling is 300 - 450 rpm, and the time is 6 - 12 h.

6. The preparation method according to claim 5, characterized in that, The wet ball milling obtains milled materials, and it also includes screening the milled materials, taking the materials under the sieve and drying them to obtain the glass powder. The sieve mesh for the screening is 500 mesh.

7. The preparation method according to claim 3, characterized in that, The reagent used for aging is polyvinyl alcohol; the mass ratio of the glass powder to the polyvinyl alcohol is 50:1 - 2.

8. The preparation method according to claim 7, characterized in that, The polyvinyl alcohol is used in the form of an aqueous solution of polyvinyl alcohol, and the mass content of polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is 2 - 5%.

9. The preparation method according to claim 3, characterized in that, The pressure for the pressing into shape is 50 - 100 MPa.

10. The preparation method according to claim 3, characterized in that, The temperature of the heat treatment is 1150 - 1350 °C, and the heat preservation time is 30 - 40 min; the heating rate for rising to the temperature of the heat treatment is 5 - 10 °C / min.

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