CN112225462A

CN112225462A - Low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for electronic paste and preparation method thereof

Info

Publication number: CN112225462A
Application number: CN202010812033.1A
Authority: CN
Inventors: 崔凤单; 高文博; 杨静; 张冰清; 张剑; 吕毅
Original assignee: Aerospace Research Institute of Materials and Processing Technology
Current assignee: Aerospace Research Institute of Materials and Processing Technology
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2021-01-15
Anticipated expiration: 2040-08-13
Also published as: CN112225462B

Abstract

The invention relates to a low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for electronic paste and a preparation method thereof. The microcrystalline glass powder comprises 55-72 wt% of SiO₂6 to 20% of Al₂O₃2-13% of B₂O₃1-8% of MgO, 0-3% of BaO, 0-3% of ZnO, 0-2% of CaO, 0-2% of ZrO2, 0-3% of rare earth oxide and 3-15% of beta-eucryptite microcrystalline glass powder. The invention adjusts the thermal expansion coefficient, dielectric constant, dielectric loss, glass transition temperature, softening temperature, crystallization temperature and the like of the lead-free glass-ceramic powder by adjusting the types and contents of oxides in the glass-ceramic powder, and adjusts the thermal expansion coefficient to be 0.5-1.6 multiplied by 10^‑6Dielectric constant of 4.5-6.0 and dielectric loss tangent of 3-5 × 10 at/° C^‑3And the wave-transparent use requirement of a specific frequency band can be met.

Description

Low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for electronic paste and preparation method thereof

Technical Field

The invention relates to a microcrystalline glass powder with a low expansion coefficient and a low dielectric constant and a preparation method thereof, in particular to the field of conductive paste for a frequency selective surface radome and a high-temperature resistant conformal antenna, and belongs to the field of glass powder.

Background

Frequency Selective Surface (FSS) radomes, high temperature resistant conformal antennas are generally made up of a ceramic substrate, a frequency selective surface attached to or within the substrate surface, and a plurality of antenna element structures, which can be obtained by screen printing using conductive paste. The glass powder is a key component of the conductive paste and is generally made of SiO₂And some metal oxides are mixed and melted according to a certain proportion, and then the mixture is quenched and crushed. The added glass powder is beneficial to reducing the sintering temperature and enhancing the adhesive force between the conductive paste and the substrate, and the performance of the conductive paste is directly influenced by the performance of the glass powder.

The existing conductive slurry mainly aims at compact substrates such as alumina ceramics, glass, silicon and the like, while the ceramic-based radome and antenna materials are generally quartz fiber reinforced silica-based composite materials, and the thermal expansion coefficient thereof is (0.47-0.58 multiplied by 10)^-6/° c) is much lower than the coefficient of thermal expansion of common glass frit, and the mismatch of the coefficient of thermal expansion causes large thermal stress between the FSS layer and the ceramic substrate layer, resulting in poor pattern adhesion. Because the antenna system bears the high-temperature airflow scouring in the flying process during operation, the antenna system can work for a long time in a severe pneumatic environment, and in order to ensure the reliability of the antenna system, the adhesion force of the FSS structure and the antenna unit structure must be improved. In addition, the components of the existing glass powder contain more alkali metal oxides, so that the existing glass powder has higher dielectric constant and dielectric loss, and the electrical properties of the FSS antenna housing and the conformal antenna are influenced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides the microcrystalline glass powder with low expansion coefficient and low dielectric constant for the electronic paste and the preparation method thereof.

The technical scheme of the invention is as follows:

in a first aspect, the invention provides a low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for electronic paste, which comprises 55-72 wt% of SiO₂6 to 20% of Al₂O₃2-13% of B₂O₃1-8% of MgO, 0-3% of BaO, 0-3% of ZnO, 0-2% of CaO and 0-2% of ZrO₂0-3% of rare earth oxide and 3-15% of beta-eucryptite microcrystalline glass powder.

Specifically, the rare earth oxide is La₂O₃、Gd₂O₃、Y₂O₃、Er₂O₃、CeO₂、Nd₂O₃One or more of them.

In a second aspect, the invention also provides a preparation method of the low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for electronic paste, which comprises the following steps:

step 1, mixing and grinding: preparing ingredients according to the weight percentage in the formula, mixing the ingredients in a mixer for 2-24 hours, and uniformly mixing;

step 2, glass melting: putting the glass powder into a corundum crucible, and keeping the temperature of the corundum crucible in a resistance furnace at 1500-1700 ℃ for 1-4 hours to obtain clear molten glass;

step 3, water quenching: quenching the glass liquid in deionized water, taking out, putting into a forced air drying oven, and drying at 80-120 ℃ for 2-6h to obtain glass slag;

step 4, ball milling: ball-milling the glass slag in a planetary ball mill for 4-8h, sieving with a 400-plus-one 500-mesh sieve to obtain basic glass powder, and controlling the average particle size of the powder to be lower than 3 mu m;

specifically, the average particle size of the powder is controlled to be 1.0-2.5 μm.

Step 5, adding beta-eucryptite into the glass powder obtained in the step 4, carrying out ball milling for 2-5h, drying, sieving by using a 300-plus 400-mesh sieve, and controlling the average particle size of the powder to be lower than 5 mu m;

and 6, melting, water quenching and drying the raw materials subjected to ball milling in the step 5 to obtain the microcrystalline glass powder.

Specifically, the melting temperature is 1250-.

The invention has the beneficial effects that:

the invention provides a low-expansion-coefficient low-dielectric-constant microcrystal for electronic pasteThe glass powder is used as a bonding agent between wave-transparent ceramic materials, the adjustment of the thermal expansion coefficient, the dielectric constant, the dielectric loss, the glass transition temperature, the softening temperature, the crystallization temperature and the like of the lead-free microcrystalline glass powder is realized by adjusting the types and the contents of various oxides in the microcrystalline glass powder, and the thermal expansion coefficient of the glass powder is finally adjusted to be 0.5 multiplied by 10^-6-1.6×10^-6Dielectric constant of 4.5-6.0 (frequency of 9 GHz)/° C, and dielectric loss tangent of 3X 10^-3-5×10^-3(the frequency is 9GHz), the wave-transparent use requirement of a specific frequency band is met; SiO in glass powder composition₂And Al₂O₃The content of (2) is high, the melting temperature and the high-temperature viscosity are high, and after the rare earth element oxide is added, due to the fact that the radius of rare earth ions is large and the coordination number is high, when the introduced amount is small, the effects of destroying a network structure and reducing the network connectivity can be achieved, the high-temperature viscosity is reduced, and the adhesive force of the slurry after sintering is improved.

Detailed Description

The technical solution of the present invention is further described below with reference to examples.

Examples one to six microcrystalline glass powder having low expansion coefficient and low dielectric constant for electronic paste was prepared as follows:

(1) mixing and grinding the ingredients: preparing ingredients according to the weight percentage in the formula, mixing the ingredients in a mixer for 12 hours, and uniformly mixing, wherein the composition and the mass percentage of each raw material are shown in table 1;

(2) melting glass: the ingredients are put into a corundum crucible, and the temperature is kept for 1.5 hours at 1600 ℃ in a resistance furnace to obtain clear molten glass;

(3) water quenching: quenching the glass liquid in deionized water, taking out, putting into a forced air drying oven, and drying for 4h at 100 ℃ to obtain glass slag;

(4) ball milling: ball-milling the glass slag in a planetary ball mill for 8 hours, and sieving with a 500-mesh sieve to obtain base glass powder with the particle size of 1.0-2.5 mu m;

(5) adding beta-eucryptite into the base glass powder, performing ball milling for 2 hours, drying, and screening by using a 400-mesh sieve, wherein the grain size of the powder is less than 5 mu m, and the mass percentage content of the base glass and the beta-eucryptite microcrystalline glass powder is shown in table 2;

(6) and (3) preserving the heat of the ball-milled raw materials in the step (5) for 1h in a resistance furnace at 1300 ℃, and after clarification, performing water quenching, ball milling and drying to obtain the microcrystalline glass powder.

In order to more intuitively explain the present invention, five groups of examples, as well as the results of the performance tests of the glass frits of each group of examples, are listed in table form below, see tables 1 and 2.

TABLE 1

TABLE 2

It can be seen from tables 1 and 2 that after eucryptite is added to the basic glass powder, the expansion coefficient of the glass powder is reduced to a certain extent, and by adjusting the addition proportion of the glass powder, the thermal expansion coefficient can be adjusted at a softening temperature lower than 800 ℃, and the dielectric constant and the dielectric loss are low, so that the use requirements of the conductive paste for the antenna and the frequency selection structure can be met.

The particular embodiments of the present invention disclosed above are illustrative only and are not intended to be limiting, since various alternatives, modifications, and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The invention should not be limited to the disclosure of the embodiments in the present specification, but the scope of the invention is defined by the appended claims.

Claims

1. The microcrystalline glass powder with the low expansion coefficient and the low dielectric constant for the electronic paste is characterized by comprising 55-72 wt% of SiO₂6 to 20% of Al₂O₃2-13% of B₂O₃1-8% of MgO, 0 &3% of BaO, 0-3% of ZnO, 0-2% of CaO, 0-2% of ZrO2, 0-3% of rare earth oxide and 3-15% of beta-eucryptite microcrystalline glass powder.

2. The microcrystalline glass powder with low expansion coefficient and low dielectric constant for electronic paste of claim 1, wherein the rare earth oxide is La₂O₃、Gd₂O₃、Y₂O₃、Er₂O₃、CeO₂、Nd₂O₃At least one of (1).

3. A method for preparing the low-expansion-coefficient low-dielectric-constant microcrystalline glass powder for the electronic paste of claim 1, which is characterized by comprising the following steps:

step 1: preparing ingredients according to the weight percentage in the formula, and mixing the ingredients in a mixer to be uniform;

step 2: putting the mixed materials into a corundum crucible, and keeping the corundum crucible in a resistance furnace at a constant temperature for a certain time to obtain clear molten glass;

and step 3: quenching the glass liquid in deionized water, taking out, and drying in a blast drying oven to obtain glass slag;

and 4, step 4: placing the glass slag in a planetary ball mill for ball milling, and sieving to obtain basic glass powder, wherein the average particle size of the powder is controlled to be lower than 3 mu m;

and 5: adding beta-eucryptite into the glass powder obtained in the step (4), performing ball milling and drying, and then screening, wherein the average particle size of the powder is controlled to be lower than 5 mu m;

step 6: and (5) melting, water quenching and drying the raw materials subjected to ball milling in the step (5) to obtain the microcrystalline glass powder.

4. The method according to claim 3, wherein the mixing time for mixing the ingredients in the mixer in step 1 is 2-24 h.

5. The method according to claim 3, wherein the constant temperature in the resistance furnace in the step 2 is kept at 1500-1700 ℃ for 1-4 h.

6. The method as claimed in claim 3, wherein the drying temperature in step 3 is 80-120 ℃ and the drying time is 2-6 h.

7. The method as claimed in claim 3, wherein step 4 comprises ball milling the glass slag in a planetary ball mill for 4-8h, and sieving with 400-500 mesh sieve to obtain the base glass powder.

8. The method according to claim 3, wherein in the step 4, the average particle diameter of the powder is controlled to be 1.0 to 2.5 μm.

9. The method as claimed in claim 3, wherein the time of the ball milling in the step 5 is 2-5h, and the sieving is performed by using a 300-400 mesh sieve.

10. The method as claimed in claim 3, wherein the melting temperature in step 6 is 1250-.