An ultralow dielectric loss aluminate microwave dielectric material and a preparation method thereof

Abstract

The application discloses an ultralow dielectric loss aluminate microwave dielectric material and a preparation method thereof. A Zn 3‑x B x AlO7, wherein A =Sr, Ba, B =Co, Ni, 0<=x<=0.08. x Its preparation process is as follows: porcelain powder solid phase reaction method synthesis, ball milling, pressing forming, sintering into porcelain. The main crystal phase of the ultralow dielectric loss aluminate microwave dielectric material is a single-phase '114' configuration compound, has the advantages of low raw material cost, low dielectric constant (10-15), high Q f Value (102000-255000 GHz), simple preparation process, good reproducibility and the like, and can solve the time delay problem of microwave signals in high-frequency communication, improve the stability of microwave signal transmission, and is very suitable for manufacturing resonators, filters, dielectric substrates and dielectric antennas and the like.

Description

Technical Field

[0001] This invention belongs to the field of microwave dielectric ceramics, and particularly relates to an ultra-low dielectric loss aluminate microwave dielectric material and its preparation method. Background Technology

[0002] Microwave dielectric ceramics have wide applications in modern communication technologies, including frequency-stabilized oscillators, filters, dielectric resonators, dielectric substrates, antennas, and surface-mount capacitors. They meet the requirements of modern microwave communication, mobile communication, satellite communication, broadcasting, radar, electronic countermeasures, and guidance technologies for microwave circuit integration, miniaturization, high reliability, and low cost. Especially with the development of 5G and 6G technologies, the application of microwave dielectric ceramics in the radio frequency units of communication base stations has become even more important, making them an indispensable key component in communication systems.

[0003] With the continuous advancement of communication technology, the performance requirements for microwave devices are becoming increasingly stringent, particularly the demand for low-loss, high-Q materials. Ultra-high dielectric loss microwave dielectric ceramics can significantly reduce insertion loss and improve signal transmission efficiency, thereby enhancing the overall performance of communication systems. Ultra-high dielectric loss microwave dielectric ceramics also have broad application prospects in high-end application fields such as satellite communication, BeiDou navigation, and electronic warfare, significantly improving the technological level and competitiveness of these fields.

[0004] Aluminate microwave dielectric ceramics are important microwave dielectric materials, and have received widespread attention and research in the field of microwave communication in recent years due to their excellent dielectric properties and good temperature stability. Aluminate microwave dielectric ceramics mainly include compounds such as CaAl2O4 and CaAl4O7. These materials have advantages such as low dielectric constant, low dielectric loss, and near-zero temperature coefficient of resonant frequency, making them valuable for applications in high-frequency electronic devices. This invention discloses an ultra-low dielectric loss aluminate microwave dielectric material and its preparation method. This compound exhibits ultra-low dielectric loss (tan φ < 10). -5 Furthermore, its low dielectric constant makes it ideal for manufacturing devices such as resonators, filters, dielectric substrates, and dielectric antennas, and it is widely used in fields such as satellite communication, BeiDou navigation, electronic countermeasures, 5G, and the Internet of Things. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-low dielectric loss aluminate microwave dielectric material and its preparation method. The main crystal phase of this material is a single "114" configuration compound, which has the advantages of low cost, low dielectric constant, ultra-low dielectric loss, strong resistance to reduction, and stable preparation process.

[0006] This invention discloses an ultra-low dielectric loss aluminate microwave dielectric material, characterized in that the chemical formula of the aluminate microwave dielectric material is Y.A Zn 3-x B x AlO7, in which A =Sr、Ba, B =Co、Ni,0≤ x ≤0.08.

[0007] The main crystalline phase of this aluminate microwave dielectric material is a single "114" configuration compound.

[0008] A method for preparing an ultra-low dielectric loss aluminate microwave dielectric material, characterized by comprising the following steps:

[0009] Step 1: Porcelain powder synthesis: Using high-purity powders of Y₂O₃, SrCO₃, BaCO₃, ZnO, CoO, NiO, and Al₂O₃ as raw materials, according to the chemical formula Y₂O₃… A Zn 3-x B x AlO7 ( A =Sr、Ba, B =Co、Ni,0≤ x Weigh and mix the ingredients (≤0.08) to form a mixed powder; place the mixed powder in a planetary ball mill for wet grinding, the grinding ball material is zirconium dioxide, the mass ratio of the mixture, grinding ball and grinding media is 1:5:1.2, the ball milling time is 6 hours, the ball mill speed is 300 rpm; after drying, transfer the mixed powder to an alumina crucible, place it in a box-type resistance furnace and heat it to 1150~1200℃, keep it at that temperature for 4~6 hours and then cool it to room temperature.

[0010] Step 2, ball milling: Transfer the synthesized aluminate ceramic powder to a nylon ball mill jar, add grinding media and grinding balls, and place it in a planetary ball mill for wet milling. The grinding balls are made of zirconium dioxide. The mass ratio of the mixture, grinding balls and grinding media is 1:5:1.2. The ball milling time is 8~12 hours and the ball mill speed is 250~350 rpm.

[0011] Step 3, pressing and molding: After drying the ball mill slurry, add 5-8 wt% of binder, mix, sieve, and granulate; press into a green body on a unidirectional press with a pressure of 100-150 MPa;

[0012] Step 4: Sintering into ceramic: The pressed blank is placed in a box-type resistance furnace and heated slowly to 500℃ and held for 2 hours, then heated to 650℃ and held for 2 hours, then heated to 1350~1450℃ and held for 4~8 hours, and finally cooled with the furnace to obtain ultra-low dielectric loss aluminate microwave dielectric material.

[0013] The particle size of the Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO and Al2O3 powders is 1~5μm and the purity is ≥99.5%.

[0014] The ball milling media is anhydrous ethanol or deionized water.

[0015] The adhesive is a 5 wt% aqueous solution of polyvinyl alcohol.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) The present invention prepares a single-phase “114” configuration compound by conventional solid-state sintering method. The compound has a special tetrahedral coordination layer. By substituting trace amounts of Co and Ni, the crystal structure of the compound can be moderately distorted, thereby significantly reducing the dielectric loss of the compound.

[0018] 2) The dielectric constant of the ultra-low dielectric loss aluminate microwave dielectric material prepared by this invention is 10~15, Q f With a value of 102000~255000GHz, it can solve the time delay problem of microwave signals in high-frequency communication and improve the stability of microwave signal transmission, making it very suitable for use in microwave substrates, dielectric antennas and other systems.

[0019] (3) The preparation process of the ultra-low dielectric loss aluminate microwave dielectric material provided by the present invention is simple, the raw material cost is low, it does not pollute the environment, the production process has good stability, and it is suitable for large-scale industrial production. Attached Figure Description

[0020] Figure 1 The image shows the XRD pattern of the ultra-low dielectric loss aluminate microwave dielectric material prepared in Example 3 of this invention.

[0021] Figure 2 This is a refined XRD structure diagram of YSrZnAlO7 obtained in Embodiment 3 of the present invention.

[0022] Figure 3 This is a microstructure image of YSrZnAlO7 prepared in Example 3 of the present invention. Detailed Implementation

[0023] The present invention will now be further described. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] Table 1 shows the mixtures of five components. Ultra-low dielectric loss aluminate microwave dielectric materials were prepared using different process parameters, and their microwave dielectric properties were measured.

[0025] Using high-purity powders of Y₂O₃, SrCO₃, BaCO₃, ZnO, CoO, NiO, and Al₂O₃ as raw materials, according to the chemical formula Y A Zn 3-x B x AlO7 ( A =Sr、Ba, B =Co、Ni,0≤ x ≤0.08)

[0026] Table 1. Mixture powder of five components (mol%)

[0027] Element <![CDATA[Y2O3]]> <![CDATA[SrCO3]]> <![CDATA[BaCO3]]> ZnO CoO NiO <![CDATA[Al2O3]]> <![CDATA[1 # ]]> 1 2 6 1 <![CDATA[2 # ]]> 1 2 6 1 <![CDATA[3 # ]]> 1 2 5.84 0.16 1 <![CDATA[4 # ]]> 1 2 5.84 0.16 1 <![CDATA[5 # ]]> 1 2 5.90 0.10 1 Example 1

[0028] Step 1: Porcelain powder synthesis: Using high-purity powders of Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO, and Al2O3 as raw materials, weigh and mix them according to Table 1 to form a mixed powder; place the mixed powder in a planetary ball mill for wet grinding, with zirconium dioxide as the grinding ball material, and the mass ratio of the mixture, grinding balls, and grinding media is 1:5:1.2, the ball milling time is 6 hours, and the ball mill speed is 300 rpm; after drying, transfer the mixed powder to an alumina crucible, place it in a box-type resistance furnace, heat it to 1150℃, hold it at that temperature for 6 hours, and then cool it to room temperature.

[0029] Step 2, ball milling: Transfer the synthesized aluminate ceramic powder to a nylon ball mill jar, add anhydrous ethanol and grinding balls, and place it in a planetary ball mill for wet milling. The grinding balls are made of zirconium dioxide. The mass ratio of the mixture, grinding balls and anhydrous ethanol is 1:5:1.2. The ball milling time is 8 hours and the ball mill speed is 350 rpm.

[0030] Step 3, pressing and molding: After drying the ball mill slurry, add 5 wt% of its weight of a 5 wt% polyvinyl alcohol aqueous solution, mix, sieve, and granulate; press into a green body on a unidirectional press with a pressure of 100 MPa;

[0031] Step 4: Sintering into ceramic: The pressed blank is placed in a box-type resistance furnace and heated slowly to 500°C and held for 2 hours, then heated to 650°C and held for 2 hours, then heated to 1350°C and held for 8 hours, and finally cooled with the furnace to obtain ultra-low dielectric loss aluminate microwave dielectric material.

[0032] The material obtained in this embodiment was subjected to performance testing, and the test results are shown in Table 2.

[0033] Table 2. Dielectric properties of different materials prepared using Example 1

[0034] Element <![CDATA[1 ＃ ]]> <![CDATA[2 ＃ ]]> <![CDATA[3 ＃ ]]> <![CDATA[4 ＃ ]]> <![CDATA[5 ＃ ]]> Dielectric constant 12.5 10 12.1 10.7 12.3 Q value (GHz) 117500 102000 158500 165100 187800 <![CDATA[ τ f (ppm / ℃)]]> -45.8 -40.2 -48.4 -42.7 -41.5 Example 2

[0035] Step 1: Porcelain powder synthesis: Using high-purity powders of Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO, and Al2O3 as raw materials, weigh and mix them according to Table 1 to form a mixed powder; place the mixed powder in a planetary ball mill for wet grinding, with zirconium dioxide as the grinding ball material, and the mass ratio of the mixture, grinding balls, and grinding media is 1:5:1.2, the ball milling time is 6 hours, and the ball mill speed is 300 rpm; after drying, transfer the mixed powder to an alumina crucible, place it in a box-type resistance furnace, heat it to 1200℃, hold it at that temperature for 4 hours, and then cool it to room temperature.

[0036] Step 2, ball milling: Transfer the synthesized aluminate ceramic powder to a nylon ball mill jar, add deionized water and grinding balls, and place it in a planetary ball mill for wet milling. The grinding balls are made of zirconium dioxide. The mass ratio of the mixture, grinding balls and deionized water is 1:5:1.2. The ball milling time is 12 hours and the ball mill speed is 250 rpm.

[0037] Step 3, pressing and molding: After drying the ball mill slurry, add 8 wt% of its weight of a 5 wt% polyvinyl alcohol aqueous solution, mix, sieve, and granulate; press into a green body on a unidirectional press at a pressure of 150 MPa;

[0038] Step 4: Sintering into ceramic: The pressed blank is placed in a box-type resistance furnace and heated slowly to 500°C and held for 2 hours, then heated to 650°C and held for 2 hours, then heated to 1450°C and held for 4 hours, and finally cooled with the furnace to obtain ultra-low dielectric loss aluminate microwave dielectric material.

[0039] The material obtained in this embodiment was subjected to performance testing, and the test results are shown in Table 3.

[0040] Table 3. Dielectric properties of different materials prepared using Example 2

[0041] Element <![CDATA[1 ＃ ]]> <![CDATA[2 ＃ ]]> <![CDATA[3 ＃ ]]> <![CDATA[4 ＃ ]]> <![CDATA[5 ＃ ]]> Dielectric constant 15 12.3 14.3 12.9 14.8 Q value (GHz) 193200 165200 215500 185500 235600 <![CDATA[ τ f (ppm / ℃)]]> -41.3 -42.8 -45.5 -40.9 -44.3 Example 3

[0042] Step 1: Porcelain powder synthesis: Using high-purity powders of Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO, and Al2O3 as raw materials, weigh and mix them according to Table 1 to form a mixed powder; place the mixed powder in a planetary ball mill for wet grinding, with zirconium dioxide as the grinding ball material, and the mass ratio of the mixture, grinding balls, and grinding media is 1:5:1.2, the ball milling time is 6 hours, and the ball mill speed is 300 rpm; after drying, transfer the mixed powder to an alumina crucible, place it in a box-type resistance furnace, heat it to 1175℃, hold it at that temperature for 5 hours, and then cool it to room temperature.

[0043] Step 2, ball milling: Transfer the synthesized aluminate ceramic powder to a nylon ball mill jar, add anhydrous ethanol and grinding balls, and place it in a planetary ball mill for wet milling. The grinding balls are made of zirconium dioxide. The mass ratio of the mixture, grinding balls and anhydrous ethanol is 1:5:1.2. The ball milling time is 10 hours and the ball mill speed is 300 rpm.

[0044] Step 3, pressing and molding: After drying the ball mill slurry, add 6 wt% of its weight of a 5 wt% polyvinyl alcohol aqueous solution, mix, sieve, and granulate; press into a green body on a unidirectional press at a pressure of 125 MPa;

[0045] Step 4: Sintering into ceramic: The pressed blank is placed in a box-type resistance furnace and heated slowly to 500°C and held for 2 hours, then heated to 650°C and held for 2 hours, then heated to 1400°C and held for 6 hours, and finally cooled with the furnace to obtain ultra-low dielectric loss aluminate microwave dielectric material.

[0046] The material obtained in this embodiment was subjected to performance testing, and the test results are shown in Table 4.

[0047] Table 4. Dielectric properties of different materials prepared using Example 3

[0048] Element <![CDATA[1 ＃ ]]> <![CDATA[2 ＃ ]]> <![CDATA[3 ＃ ]]> <![CDATA[4 ＃ ]]> <![CDATA[5 ＃ ]]> Dielectric constant 14.2 11.3 13.5 11.6 13.6 Q value (GHz) 216300 177300 223100 194500 255000 <![CDATA[ τ f (ppm / ℃)]]> -45.2 -45.1 -45.5 -40.9 -45.8

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-low dielectric loss aluminate microwave dielectric material, characterized in that, The chemical formula for this aluminate microwave dielectric material is Y. A Zn 3-x B x AlO7, in which A =Sr、Ba, B =Co、Ni,0< x ≤0.08; The preparation method includes the following steps: Step 1: Porcelain powder synthesis: Single-phase aluminate porcelain powder is prepared by solid-state sintering using high-purity powders of Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO and Al2O3 as raw materials. Step 2, ball milling: Transfer the synthesized aluminate ceramic powder to a nylon ball mill jar, add grinding media and grinding balls, and place it in a planetary ball mill for wet milling. The grinding balls are made of zirconium dioxide. The mass ratio of the mixture, grinding balls and grinding media is 1:5:1.

2. The ball milling time is 8~12 hours and the ball mill speed is 250~350 rpm. Step 3, pressing and molding: After drying the ball mill slurry, add 5-8 wt% of binder, mix, sieve, and granulate; press into a green body on a unidirectional press with a pressure of 100-150 MPa; Step 4: Sintering into ceramic: The pressed blank is placed in a box-type resistance furnace and heated slowly to 500°C and held for 2 hours. Then it is heated to 650°C and held for 2 hours. Finally, it is heated to the sintering temperature of 1400~1450°C and held for 4~8 hours. Finally, it is cooled with the furnace to obtain the ultra-low dielectric loss aluminate microwave dielectric material.

2. The method for preparing an ultra-low dielectric loss aluminate microwave dielectric material according to claim 1, characterized in that, The main crystalline phase of this aluminate microwave dielectric material is a single "114" configuration compound.

3. The method for preparing an ultra-low dielectric loss aluminate microwave dielectric material according to claim 1, characterized in that, The particle size of the Y2O3, SrCO3, BaCO3, ZnO, CoO, NiO and Al2O3 powders mentioned in step one is 1~5μm and the purity is ≥99.5%.

4. The method for preparing an ultra-low dielectric loss aluminate microwave dielectric material according to claim 1, characterized in that, The specific method for preparing single-phase aluminate ceramic powder by solid-state sintering in step one is as follows: Y₂O₃, SrCO₃, BaCO₃, ZnO, CoO, NiO, and Al₂O₃ raw material powders are prepared according to the chemical formula Y₂O₃. A Zn 3-x B x AlO7, in which A =Sr、Ba, B =Co、Ni,0< x ≤0.08, weigh and mix the ingredients to form a mixed powder; place the mixed powder in a planetary ball mill for wet grinding, the grinding ball material is zirconium dioxide, the mass ratio of the mixture, grinding ball and grinding media is 1:5:1.2, the ball milling time is 6 hours, the ball mill speed is 300 rpm; after drying, transfer the mixed powder to an alumina crucible, place it in a box-type resistance furnace and heat it to 1150~1200℃, keep it at that temperature for 4~6 hours and then cool it to room temperature.

5. The method for preparing an ultra-low dielectric loss aluminate microwave dielectric material according to claim 1, characterized in that, The ball milling medium mentioned in step two is anhydrous ethanol or deionized water.

6. The method for preparing an ultra-low dielectric loss aluminate microwave dielectric material according to claim 1, characterized in that, The adhesive mentioned in step three is a 5 wt% aqueous solution of polyvinyl alcohol.

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