Glass powder used in microwave dielectric ceramic metallized silver paste and preparation process thereof

Abstract

The invention discloses glass powder used in microwave dielectric ceramic metallized silver paste and a preparation process thereof, and relates to the field of dissimilar material connection, and the raw material powder comprises the following components in percentage by mass: 35-55% of bismuth oxide powder, 15-35% of boron oxide powder, 15% of silicon oxide powder, 9% of zinc oxide powder, 3% of calcium oxide powder and 3% of aluminum oxide powder. The process comprises the following steps: firstly, accurately weighing raw material powder in proportion, and uniformly mixing in a dry ball-milling manner; pouring into an alumina crucible, compacting by vibration, and smelting in a high-temperature lifting furnace; then carrying out water quenching on the molten glass liquid, and carrying out coarse crushing by using a jaw crusher; and refining the coarsely crushed sample through a wet ball milling process to finally obtain the glass powder for the microwave dielectric ceramic metallized silver paste, wherein D50 is less than 0.5 mu m. According to the preparation process provided by the invention, the glass powder with high thermal stability and good compatibility with K-27 microwave dielectric ceramic with the dielectric constant of 27 can be prepared under more environment-friendly, convenient and economic conditions.

Description

Technical Field

[0001] The invention relates to the technical field of dissimilar material connection, and in particular to a glass powder used in a silver paste for metallization of microwave dielectric ceramics and a preparation process thereof. Background Art

[0002] In order to apply microwave dielectric ceramic materials to the field of radio frequency antenna technology, people have conducted a lot of research on the connection process between microwave dielectric ceramics and metals. At present, the processes for ceramic metallization include molybdenum-manganese metallization, direct bonding copper (DBC), direct copper plating (DPC), chemical copper plating and screen printing thick film metallization. Among them, the screen printing thick film metallization process is widely used in industrial production due to its low cost and stable process.

[0003] In the screen printing metallization process, the performance of the electronic paste will directly affect the performance of the subsequent metal layer. Silver electronic paste is composed of functional phase metal particles (Ag), bonding phase glass powder and organic carrier. Because of its certain thixotropy, it can meet the requirements of the screen printing process for paste-type materials. Among them, glass is the material that connects the metal particles to the ceramic substrate during the sintering process and forms a surface metal conductive network. It is required to have good fluidity, low thermal expansion coefficient, high thermal stability, and good compatibility with the ceramic substrate.

[0004] The glass powder systems in traditional silver pastes are mostly borosilicate glass and PbO-based glass. Comparing the two glass systems, borosilicate glass has a high glass transition temperature, high glass softening temperature, low thermal stability and poor fluidity, which requires high process temperature during the silver paste sintering process, thereby increasing production costs; although PbO-based glass has the advantages of low glass softening temperature, low thermal expansion coefficient and high chemical stability, PbO-based glass usually has a high lead content, and heavy metal elements such as mercury, cadmium and chromium are added to achieve excellent connection performance. Therefore, the production of PbO-based glass will cause significant pollution to the environment. Therefore, it is necessary to find a high-performance, harmless, low-cost glass system that has good compatibility with MgTiO3-based microwave dielectric ceramics. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art. The present invention provides a glass powder for use in microwave dielectric ceramic metallization silver paste and a preparation process thereof. An amorphous glass powder of a Bi2O3-B2O3-SiO2-ZnO system is prepared by high-temperature smelting, water quenching and wet ball milling.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A glass powder used in a silver paste for metallization of microwave dielectric ceramics. The raw material powders required for preparing the glass powder and their mass fraction ratios are as follows: 35-55wt.% bismuth oxide powder (Bi2O3), 15-35wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0008] Furthermore, among the glass powder, more than 90% of the glass powder has a particle size less than 1 μm, and more than 50% of the glass powder has a particle size less than 0.5 μm.

[0009] A preparation process for glass powder in microwave dielectric ceramic metallization silver paste, the preparation process comprising the following steps:

[0010] Step S1: accurately weighing the raw material powders needed to prepare the glass according to a certain ratio, and pouring the weighed raw materials into a ball mill to mix the raw materials by dry ball milling;

[0011] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting;

[0012] Step S3: placing the crucible into a high-temperature lifting furnace, setting a heating curve to perform high-temperature melting operation on the raw material powder;

[0013] Step S4: pouring the melted glass liquid into water for water quenching to obtain irregular glass samples of different sizes, and placing the quenched glass samples in an oven for drying;

[0014] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them using a jaw crusher;

[0015] Step S6: using an ultrasonic cleaning machine to wash away surface impurities of the coarsely crushed sample, and placing the cleaned sample in an oven for drying;

[0016] Step S7: further refine the particle size of the glass sample by wet ball milling; take out the glass powder suspension after wet ball milling and put it into an oven for drying;

[0017] Step S8: Grind and sieve the dried glass powder to obtain glass powder for microwave dielectric ceramic metallization silver paste with D50 < 0.5 μm.

[0018] Furthermore, in step S1, the ball milling process parameters of the dry ball milling are set as follows: the rotation speed is set to 400 rads / min, and the ball milling mixing time is set to 3-5 hours.

[0019] Furthermore, in step S3, the temperature of the high temperature smelting operation is set as follows: the heating rate is set to 5-10°C / min, and the smelting is completed at 1200-1300°C for 90-120 minutes.

[0020] Furthermore, in step S4, the parameters of the water quenching and the drying treatment operations are set as follows: the water temperature used in the water quenching operation is set at 25-30°C, the temperature of the oven is set at 55-65°C, and the drying time is 30-40 minutes.

[0021] Furthermore, in step S5, the parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.5-1.0 mm, and the roller speed is 50 rads / min.

[0022] Furthermore, in step S6, the ultrasonic cleaning machine uses anhydrous ethanol as a cleaning liquid to clean the surface of the glass sample for 120 seconds; the temperature of the oven is set to 55-65° C., and the drying time is 30-40 minutes.

[0023] Furthermore, in step S7, the wet ball milling process uses anhydrous ethanol as a grinding medium, the mass ratio of the ball mill to the powder is 1.5:1 to 2:1, and the ball mill parameters are set as follows: the rotation speed is 400 rads / min, and the ball milling time is 36 to 48 hours; the temperature of the oven is set to 60 to 75°C, and the drying time is 6 to 8 hours.

[0024] Furthermore, in step S8, the dried glass powder is ground using a corundum mortar and sieved using a 500-mesh sieve.

[0025] Compared with the prior art, the present invention adopts the above technical solution and has the following beneficial effects:

[0026] 1. The present invention provides a glass powder for use in silver paste for metallization of microwave dielectric ceramics and a preparation process thereof. By designing a Bi2O3-B2O3-SiO2-ZnO system glass, the advantages of low glass softening temperature, low glass transition temperature, high thermal stability, low thermal expansion coefficient and high chemical stability are achieved.

[0027] 2. The present invention provides a glass powder for use in silver paste for metallization of microwave dielectric ceramics and a preparation process thereof. The chemicals involved in the preparation process are non-toxic and will not cause environmental pollution.

[0028] 3. The present invention provides a glass powder for use in silver paste for metallization of microwave dielectric ceramics and a preparation process thereof. Through the wettability test with MgTiO3-based microwave dielectric ceramics, it is found that the glass system has excellent compatibility with MgTiO3-based microwave dielectric ceramics.

[0029] 4. The present invention provides a glass powder for use in microwave dielectric ceramic metallization silver paste and its preparation process. The chemical reagents used are low-priced, convenient and easy to obtain, which greatly reduces the cost of glass powder preparation.

[0030] 5. The present invention provides a glass powder for use in microwave dielectric ceramic metallization silver paste and a preparation process thereof, which adopts an omnidirectional wet ball milling process so that the prepared glass powder has a lower particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a process flow chart for preparing glass powder used in silver paste for metallization of microwave dielectric ceramics.

[0032] Figure 2 This is a picture of the wetting angle between the sample glass powder prepared in Example 1 and K-27 ceramic.

[0033] Figure 3 This is a picture of the wetting angle between the sample glass powder prepared in Example 2 and K-27 ceramic.

[0034] Figure 4 This is a picture of the wetting angle between the sample glass powder prepared in Example 3 and K-27 ceramic.

[0035] Figure 5 This is a picture of the wetting angle between the sample glass powder prepared in Example 4 and K-27 ceramic.

[0036] Figure 6 This is a picture of the wetting angle between the sample glass powder prepared in Example 5 and K-27 ceramic.

[0037] Figure 7 This is the DTA test curve of the sample glass powder prepared in Examples 1-5.

[0038] Figure 8 : is the thermal expansion curve of the sample glass powder prepared in Examples 1-5.

[0039] Fig. 9 : Characteristic temperature change curve of the sample glass powder in Examples 1-5.

[0040] Fig.10 This is a natural surface microscopic morphology of the sample glass powder in Example 1 after sintering at 600°C.

[0041] Fig.11This is a natural surface microscopic morphology of the sample glass powder in Example 2 after sintering at 600°C.

[0042] Fig.12 This is a natural surface microscopic morphology of the sample glass powder in Example 3 after sintering at 600°C.

[0043] Fig.13 This is a natural surface microscopic morphology of the sample glass powder in Example 4 after sintering at 600°C.

[0044] Fig.14 This is a natural surface microscopic morphology of the sample glass powder in Example 5 after sintering at 600°C.

[0045] Fig.15 This is the wetting angle variation curve of the sample glass powder in Example 4 on the K-27 ceramic surface.

[0046] Fig.16 This is the particle size distribution diagram of the sample glass powder in Example 4. DETAILED DESCRIPTION

[0047] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are provided to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may also be implemented in other embodiments without these specific details.

[0048] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0049] A glass powder used in a silver paste for metallization of microwave dielectric ceramics. The raw material powders required for preparing the glass powder and their mass fraction ratios are as follows: 35-55wt.% bismuth oxide powder (Bi2O3), 15-35wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0050] Furthermore, in the glass powder, more than 90% of the glass powder has a particle size less than 1 μm, and more than 50% of the glass powder has a particle size less than 0.5 μm. Fig.16 shown.

[0051] A preparation process for glass powder in microwave dielectric ceramic metallization silver paste, the preparation process comprising the following steps: Figure 1 As shown:

[0052] Step S1: accurately weighing the raw material powders needed to prepare the glass according to a certain ratio, and pouring the weighed raw materials into a ball mill to mix the raw materials by dry ball milling;

[0053] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting;

[0054] Step S3: placing the crucible into a high-temperature lifting furnace, setting a heating curve to perform high-temperature melting operation on the raw material powder;

[0055] Step S4: pouring the melted glass liquid into water for water quenching to obtain irregular glass samples of different sizes, and placing the quenched glass samples in an oven for drying;

[0056] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them using a jaw crusher;

[0057] Step S6: using an ultrasonic cleaning machine to wash away surface impurities of the coarsely crushed sample, and placing the cleaned sample in an oven for drying;

[0058] Step S7: further refine the particle size of the glass sample by wet ball milling; take out the glass powder suspension after wet ball milling and put it into an oven for drying;

[0059] Step S8: Grind and sieve the dried glass powder to obtain glass powder for microwave dielectric ceramic metallization silver paste with D50 < 0.5 μm.

[0060] Furthermore, in step S1, the ball milling process parameters of the dry ball milling are set as follows: the rotation speed is set to 400 rads / min, and the ball milling mixing time is set to 3-5 hours.

[0061] Furthermore, in step S3, the temperature of the high temperature smelting operation is set as follows: the heating rate is set to 5-10°C / min, and the smelting is completed at 1200-1300°C for 90-120 minutes.

[0062] Furthermore, in step S4, the parameters of the water quenching and the drying treatment operations are set as follows: the water temperature used in the water quenching operation is set at 25-30°C, the temperature of the oven is set at 55-65°C, and the drying time is 30-40 minutes.

[0063] Furthermore, in step S5, the parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.5-1.0 mm, and the roller speed is 50 rads / min.

[0064] Furthermore, in step S6, the ultrasonic cleaning machine uses anhydrous ethanol as a cleaning liquid to clean the surface of the glass sample for 120 seconds; the temperature of the oven is set to 55-65° C., and the drying time is 30-40 minutes.

[0065] Furthermore, in step S7, the wet ball milling process uses anhydrous ethanol as a grinding medium, the mass ratio of the ball mill to the powder is 1.5:1 to 2:1, and the ball mill parameters are set as follows: the rotation speed is 400 rads / min, and the ball milling time is 36 to 48 hours; the temperature of the oven is set to 60 to 75°C, and the drying time is 6 to 8 hours.

[0066] Furthermore, in step S8, the dried glass powder is ground using a corundum mortar and sieved using a 500-mesh sieve.

[0067] The following are the specific parameters in each operation:

[0068] Example 1

[0069] Step S1: Accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling. The raw material powders needed to prepare the glass and their mass fraction ratios are as follows: 35wt.% bismuth oxide powder (Bi2O3), 35wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0070] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting.

[0071] Step S3: placing the crucible into a high-temperature lifting furnace, setting the heating rate to 5°C / min, the melting temperature to 1300°C, and the melting time to 120min to perform high-temperature melting operation on the raw material powder.

[0072] Step S4: pour the melted glass liquid into 25°C water for water quenching to obtain irregular glass samples of different sizes, and put the quenched glass samples into an oven for drying. The oven temperature is set to 60°C and the drying time is 40 minutes.

[0073] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them by using a jaw crusher. The working parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.8 mm, and the roller speed is 50 rad / min.

[0074] Step S6: Use an ultrasonic cleaner to wash away surface impurities of the coarsely crushed sample, select anhydrous ethanol as the washing medium, and wash for 120 seconds. Put the washed sample into an oven for drying, the oven temperature is set to 60°C, and the drying time is 40 minutes.

[0075] Step S7: The glass sample is further refined through a wet ball milling process to obtain a particle size of the glass sample. During the wet ball milling process, anhydrous ethanol is selected as the ball milling medium. The mass ratio of the grinding grains to the glass sample is 1.5:1. The ball mill parameters are set to a rotation speed of 400 rads / min and a ball milling time of 36 h. The glass powder suspension after ball milling is taken out and placed in an oven for drying. The temperature of the oven is set to 60°C and the drying time is 8 h.

[0076] Step S8: Grind the dried glass powder and pass it through a 400-mesh sieve. After sieving three times, glass powder for microwave dielectric ceramic metallization silver paste can be obtained.

[0077] Example 2

[0078] Step S1: Accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling. The raw material powders needed to prepare the glass and their mass fraction ratios are as follows: 40wt.% bismuth oxide powder (Bi2O3), 30wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0079] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting.

[0080] Step S3: placing the crucible into a high-temperature lifting furnace, setting the heating rate to 5°C / min, the melting temperature to 1300°C, and the melting time to 120min to perform high-temperature melting operation on the raw material powder.

[0081] Step S4: pour the melted glass liquid into 25°C water for water quenching to obtain irregular glass samples of different sizes. Put the quenched glass samples into an oven for drying. The oven temperature is set to 60°C and the drying time is 40 minutes.

[0082] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them by using a jaw crusher. The working parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.8 mm, and the roller speed is 50 rad / min.

[0083] Step S6: Use an ultrasonic cleaner to wash away surface impurities of the coarsely crushed sample, select anhydrous ethanol as the washing medium, and wash for 120 seconds. Put the washed sample into an oven for drying, the oven temperature is set to 60°C, and the drying time is 40 minutes.

[0084] Step S7: The glass sample is further refined through a wet ball milling process to obtain a particle size of the glass sample. During the wet ball milling process, anhydrous ethanol is selected as the ball milling medium. The mass ratio of the grinding grains to the glass sample is 1.5:1. The ball mill parameters are set to a rotation speed of 400 rads / min and a ball milling time of 36 h. The glass powder suspension after ball milling is taken out and placed in an oven for drying. The temperature of the oven is set to 60°C and the drying time is 8 h.

[0085] Step S8: Grind the dried glass powder and pass it through a 400-mesh sieve. After sieving three times, glass powder for microwave dielectric ceramic metallization silver paste can be obtained.

[0086] Example 3

[0087] Step S1: Accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling. The raw material powders needed to prepare the glass and their mass fraction ratios are as follows: 45wt.% bismuth oxide powder (Bi2O3), 25wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0088] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting.

[0089] Step S3: placing the crucible into a high-temperature lifting furnace, setting the heating rate to 5°C / min, the melting temperature to 1300°C, and the melting time to 120min to perform high-temperature melting operation on the raw material powder.

[0090] Step S4: pour the melted glass liquid into 25°C water for water quenching to obtain irregular glass samples of different sizes. Put the quenched glass samples into an oven for drying. The oven temperature is set to 60°C and the drying time is 40 minutes.

[0091] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them by using a jaw crusher. The working parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.8 mm, and the roller speed is 50 rad / min.

[0092] Step S6: Use an ultrasonic cleaner to wash away surface impurities of the coarsely crushed sample, select anhydrous ethanol as the washing medium, and wash for 120 seconds. Put the washed sample into an oven for drying, the oven temperature is set to 60°C, and the drying time is 40 minutes.

[0093] Step S7: The glass sample is further refined through a wet ball milling process to obtain a particle size of the glass sample. During the wet ball milling process, anhydrous ethanol is selected as the ball milling medium. The mass ratio of the grinding grains to the glass sample is 1.5:1. The ball mill parameters are set to a rotation speed of 400 rads / min and a ball milling time of 36 h. The glass powder suspension after ball milling is taken out and placed in an oven for drying. The temperature of the oven is set to 60°C and the drying time is 8 h.

[0094] Step S8: Grind the dried glass powder and pass it through a 400-mesh sieve. After sieving three times, glass powder for microwave dielectric ceramic metallization silver paste can be obtained.

[0095] Example 4

[0096] Step S1: Accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling. The raw material powders needed to prepare the glass and their mass fraction ratios are as follows: 50wt.% bismuth oxide powder (Bi2O3), 20wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0097] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting.

[0098] Step S3: placing the crucible into a high-temperature lifting furnace, setting the heating rate to 5°C / min, the melting temperature to 1300°C, and the melting time to 120min to perform high-temperature melting operation on the raw material powder.

[0099] Step S4: pour the melted glass liquid into 25°C water for water quenching to obtain irregular glass samples of different sizes. Put the quenched glass samples into an oven for drying. The oven temperature is set to 60°C and the drying time is 40 minutes.

[0100] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them by using a jaw crusher. The working parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.8 mm, and the roller speed is 50 rad / min.

[0101] Step S6: Use an ultrasonic cleaner to wash away surface impurities of the coarsely crushed sample, select anhydrous ethanol as the washing medium, and wash for 120 seconds. Put the washed sample into an oven for drying, the oven temperature is set to 60°C, and the drying time is 40 minutes.

[0102] Step S7: The glass sample is further refined through a wet ball milling process to obtain a particle size of the glass sample. During the wet ball milling process, anhydrous ethanol is selected as the ball milling medium. The mass ratio of the grinding grains to the glass sample is 1.5:1. The ball mill parameters are set to a rotation speed of 400 rads / min and a ball milling time of 36 h. The glass powder suspension after ball milling is taken out and placed in an oven for drying. The temperature of the oven is set to 60°C and the drying time is 8 h.

[0103] Step S8: Grind the dried glass powder and pass it through a 400-mesh sieve. After sieving three times, glass powder for microwave dielectric ceramic metallization silver paste can be obtained.

[0104] Example 5

[0105] Step S1: Accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling. The raw material powders needed to prepare the glass and their mass fraction ratios are as follows: 55wt.% bismuth oxide powder (Bi2O3), 15wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

[0106] Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting.

[0107] Step S3: placing the crucible into a high-temperature lifting furnace, setting the heating rate to 5°C / min, the melting temperature to 1300°C, and the melting time to 120min to perform high-temperature melting operation on the raw material powder.

[0108] Step S4: pour the melted glass liquid into 25°C water for water quenching to obtain irregular glass samples of different sizes. Put the quenched glass samples into an oven for drying. The oven temperature is set to 60°C and the drying time is 40 minutes.

[0109] Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them by using a jaw crusher. The working parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.8 mm, and the roller speed is 50 rad / min.

[0110] Step S6: Use an ultrasonic cleaner to wash away surface impurities of the coarsely crushed sample, select anhydrous ethanol as the washing medium, and wash for 120 seconds. Put the washed sample into an oven for drying, the oven temperature is set to 60°C, and the drying time is 40 minutes.

[0111] Step S7: The glass sample is further refined through a wet ball milling process to obtain a particle size of the glass sample. During the wet ball milling process, anhydrous ethanol is selected as the ball milling medium. The mass ratio of the grinding grains to the glass sample is 1.5:1. The ball mill parameters are set to a rotation speed of 400 rads / min and a ball milling time of 36 h. The glass powder suspension after ball milling is taken out and placed in an oven for drying. The temperature of the oven is set to 60°C and the drying time is 8 h.

[0112] Step S8: Grind the dried glass powder and pass it through a 400-mesh sieve. After sieving three times, glass powder for microwave dielectric ceramic metallization silver paste can be obtained.

[0113] Performance Testing

[0114] The glass powder sample prepared in the above embodiment and K-27 microwave dielectric ceramic were tested for wetting angle at 775°C. The test data are shown in Table 1. The test instrument was a SONY series industrial microscope and the wetting angle analysis software was S-EYE. Figure 2-6 shown.

[0115] Table 1

[0116] sample Wetting Angle Example 1 17.35° Example 2 58.40° Example 3 57.50° Example 4 1.91° Example 5 44.08°

[0117] The sample glass powders prepared in Examples 1-5 were subjected to DTA, thermal expansion coefficient tests, and characteristic temperature change observations. The specific data curves are as follows: Figure 7-9 shown.

[0118] The sample glass powders prepared in Examples 1-5 were pressed and sintered, and the microscopic morphology of the natural surface was characterized by SEM test. Figure 10-14 shown.

[0119] The sample glass powder prepared in Example 4 was tested for particle size, and its particle size distribution was as follows: Fig.14 shown.

[0120] Depend on Figure 2-8 The results show that the glass powder samples with low glass transition temperature, high thermal stability, low thermal expansion coefficient and good compatibility with K-27 ceramics can be prepared in the embodiments of the present invention; Figure 10-14It can be seen that the glass powder prepared in Example 4 has the lowest sintering temperature. In the silver paste sintering process, it can be reflected that the glass powder has good fluidity and a lower sintering temperature. In summary, Example 4 has the most excellent performance and can be used for the preparation of K-27 microwave dielectric ceramic metallization silver paste.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A glass powder for silver paste metallization of microwave dielectric ceramics, characterized in that: The raw material powders required for the preparation of the glass powder and their mass fraction ratios are as follows: 35-55wt.% bismuth oxide powder (Bi2O3), 15-35wt.% boron oxide powder (B2O3), 15wt.% silicon oxide powder (SiO2), 9wt.% zinc oxide powder (ZnO), 3wt.% calcium oxide powder (CaO), and 3wt.% aluminum oxide powder (Al2O3).

2. The glass powder used in silver paste for metallization of microwave dielectric ceramics according to claim 1, characterized in that: Among the glass powder, more than 90% of the glass powder has a particle size less than 1 μm, and more than 50% of the glass powder has a particle size less than 0.5 μm.

3. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 1, characterized in that: The preparation process comprises the following steps: Step S1: accurately weigh the raw material powders needed to prepare the glass according to a certain ratio, and pour the weighed raw materials into a ball mill to mix the raw materials by dry ball milling; Step S2: pouring the mixed raw materials into an alumina crucible and compacting the raw material powder to prevent the glass liquid from overflowing the crucible during high-temperature melting; Step S3: placing the crucible into a high-temperature lifting furnace, setting a heating curve to perform high-temperature melting operation on the raw material powder; Step S4: pouring the melted glass liquid into water for water quenching to obtain irregular glass samples of different sizes, and placing the quenched glass samples in an oven for drying; Step S5: collecting the glass samples after water quenching and drying, and coarsely crushing them using a jaw crusher; Step S6: using an ultrasonic cleaning machine to wash away surface impurities of the coarsely crushed sample, and placing the cleaned sample in an oven for drying; Step S7: further refine the particle size of the glass sample by wet ball milling; take out the glass powder suspension after wet ball milling and put it into an oven for drying; Step S8: Grind and sieve the dried glass powder to obtain glass powder for microwave dielectric ceramic metallization silver paste with D50 < 0.5 μm.

4. A process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S1, the ball milling process parameters of the dry ball milling are set as follows: the rotation speed is set to 400 rads / min, and the ball milling mixing time is set to 3-5 hours.

5. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S3, the temperature of the high temperature smelting operation is set as follows: the heating rate is set to 5-10°C / min, and the smelting is completed at 1200-1300°C for 90-120 minutes.

6. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S4, the parameters of the water quenching and the drying treatment operations are set as follows: the water temperature used in the water quenching operation is set at 25-30° C., the temperature of the oven is set at 55-65° C., and the drying time is 30-40 minutes.

7. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S5, the parameters of the jaw crusher are set as follows: the spacing between the rollers is 0.5-1.0 mm, and the roller speed is 50 rads / min.

8. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S6, the ultrasonic cleaning machine uses anhydrous ethanol as a cleaning liquid to clean the surface of the glass sample for 120 seconds; the temperature of the oven is set at 55-65° C., and the drying time is 30-40 minutes.

9. The process for preparing glass powder for metallization silver paste of microwave dielectric ceramics according to claim 2, characterized in that: In step S7, the wet ball milling process uses anhydrous ethanol as the grinding medium, the mass ratio of the ball mill to the powder is 1.5:1 to 2:1, and the ball mill parameters are set as follows: the rotation speed is 400 rads / min, and the ball milling time is 36 to 48 hours; the temperature of the oven is set to 60 to 75°C, and the drying time is 6 to 8 hours.

10. The process for preparing glass powder in silver paste for metallization of microwave dielectric ceramics according to claim 2, characterized in that: In step S8, the dried glass powder is ground using a corundum mortar and then sieved using a 500-mesh sieve.

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