CN116854454B - Microwave dielectric ceramic composition, microwave dielectric ceramic material and application thereof - Google Patents

Abstract

The invention relates to a microwave dielectric ceramic composition, a microwave dielectric ceramic material and its application. The microwave dielectric ceramic composition includes the following components by weight: SrO or BaO ceramic powder: 2 to 20 parts; P ₂ O ₅ ceramic Powder: 5 to 83 parts; SiO ₂ ceramic powder: 17 to 95 parts; B ₂ O ₃ ceramic powder: 0 to 5 parts; TiO ₂ ceramic powder: 0 to 10 parts. The microwave dielectric ceramic material prepared based on the composition has a dielectric constant Er of 3.9 to 8.4, a Qxf value of 63000 to 80000 GHz, a resonant frequency temperature coefficient of ±12 ppm/℃, and an expansion coefficient CTE of 10 to 18 ppm/℃. It has low dielectric constant, high quality factor, low temperature dependence of resonant frequency, and an expansion coefficient range that matches the PCB circuit board. It is of great significance for realizing the application of high-frequency devices such as microwave, millimeter wave or terahertz.

Description

Microwave dielectric ceramic composition, microwave dielectric ceramic material and application thereof

Technical field

The invention relates to the technical field of ceramic materials, specifically to a microwave dielectric ceramic composition, microwave dielectric ceramic materials and their applications, and in particular to a microwave with low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and large expansion coefficient. Dielectric ceramics and their applications.

Background technique

Microwave dielectric ceramics refer to ceramic materials that serve as dielectric materials in circuits with microwave frequency (f) (300MHz ~ 300GHz) and play the functions of conduction, resonance and filtering. They are used to prepare filters, resonators, oscillators, dielectric antennas and Key materials for microwave components such as dielectric substrates. In the past ten years, microwave dielectric ceramics and their related electronic components have been widely used in satellite communications and communication base stations, radars, smartphones, car phones, Internet of Things (IOT), Global Positioning System (GPS), Bluetooth (Blue-tooth) technology and wireless technology. Applications in modern communication systems such as local area networks (WLANs) are becoming increasingly widespread.

In order to increase bandwidth and data transmission rate, higher requirements have been put forward for the main performance parameters of microwave dielectric materials, such as dielectric constant (εr), quality factor Q, resonant frequency temperature coefficient (τf), etc. Because the transmission rate of electromagnetic waves is inversely proportional to the square root of the dielectric constant (εr) of the dielectric material, a low dielectric constant (εr<6) is beneficial to improving the transmission rate of electromagnetic signals and can reduce the interactive coupling loss between electrodes; The higher the frequency, the greater the transmission loss. The high quality factor Qxf dielectric material helps reduce the insertion loss and transmission loss of the device; and the near-zero temperature coefficient of the resonant frequency ensures that the microwave device maintains its performance when the ambient temperature changes. The center frequency will not drift, thereby ensuring the normal operation of the microwave device; and the expansion coefficient of about 15ppm/℃ can ensure that the material can match the expansion coefficient of the PCB circuit board after being prepared into a device, preventing heat generation between the device and the substrate It will fall off due to stress, thereby ensuring that the device can work stably for a long time. Therefore, research and development of new microwave dielectric materials with low dielectric constant, high quality factor, near-zero temperature coefficient and appropriate expansion coefficient are of great significance for the realization of high-frequency device applications such as microwave, millimeter wave or terahertz.

Most of the ceramic materials with dielectric constants less than 6 reported so far are based on phosphorus boroaluminosilicate compounds with tetrahedral vertex angle-connected open structures, such as SiO ₂ , AlPO ₄ , BPO ₄ , SiO ₂ -AlPO ₄ -BPO ₄ , Acrylic stone (2Al ₂ O ₃ =2MgO-5SiO ₂ ), Li ₂ MgSiO ₄ , etc.

SiO ₂ has good microwave dielectric properties: εr=3.81, Q×f=80,400GHz, τf=-16.1ppm/℃, but its sintering temperature is too high (1675℃), and there are various reversible properties during the sintering process. Phase changes are prone to microcracks. BPO ₄ ceramics are difficult to sinter densely due to the volatilization of B and P. AlPO ₄ has no shrinkage when sintered at a very high temperature (1650°C). The ceramic material obtained by adding MgF ₂ has an ultra-low dielectric constant of 3, but its dielectric loss is high. Through Si-Zn co-doping (Al1-x(Zn _0.5 Si _0.5 )xPO ₄ ), the sintering temperature can be greatly reduced and the Qxf value can be increased. The 45AlPO ₄ –45BPO ₄ –10SiO ₂ component in the AlPO ₄ –BPO ₄ –SiO ₂ ternary system has good microwave dielectric properties after sintering at 1175℃/2h: εr～4.16, Q×f～59,519GHz, τf＝ -19ppm/℃.

The resonant frequency temperature coefficient of all these low-dielectric ceramic materials presents a large negative value and cannot meet the requirements for near-zero resonant frequency temperature coefficient in practical applications. To adjust the resonant frequency temperature coefficient of the material, solid solution doping is usually used to change the crystal structure and There are two methods of adding a second phase with an opposite resonant frequency temperature coefficient to form a composite material. For phosphorus boroaluminosilicate compounds with stable tetrahedral coordination structures, solid solution doped ions are very limited and have limited effects. Although adding a second phase with a large positive temperature coefficient such as _TiO2 can coordinate the resonant frequency temperature coefficient to near zero, it usually results in the dielectric constant of the material being much greater than 6 or the expansion coefficient being low, which cannot meet the requirements of IC circuits ( About 15ppm/℃); for example, the dielectric constant Er of SiO ₂ -TiO ₂ based materials is between 5.4 and 6, the Qxf value is on the order of 40,000, the resonant frequency temperature coefficient tf reaches zero, but the expansion coefficient is only 8ppm/℃. In some cases, chemical reactions will occur between the two phases, causing the temperature coefficient coordination to fail. For example, BPO ₄ + TiO ₂ will react to form TiP ₂ O ₇ and (TiO) ₂ P ₂ O when sintering above 1000 degrees. ₇ Impurity phase reduces the coordination effect of temperature coefficient.

Currently, there is no dielectric ceramic material that simultaneously meets the requirements of low dielectric constant, near-zero resonant frequency temperature coefficient, high expansion coefficient, and high quality factors.

Contents of the invention

The purpose of the present invention is to provide a microwave dielectric ceramic composition, a microwave dielectric ceramic material and its application with low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and suitable expansion coefficient. Specifically, a microwave dielectric ceramic with a low dielectric constant Er of 3.9 to 8.4, a high Qxf value of 63000 to 80000GHz, a low resonant frequency temperature dependence of ±12ppm/℃, and an expansion coefficient CTE of 10 to 18ppm/℃ is provided. And make the changes of low dielectric constant Er, quality factor Qxf value and resonant frequency temperature coefficient Tf smaller, thereby stably controlling these characteristic values.

Based on this, the technical solutions adopted by the present invention are as follows:

In a first aspect, the present invention relates to a microwave dielectric ceramic composition, comprising the following components by weight:

SrO or BaO ceramic powder: 2 to 20 parts;

P ₂ O ₅ ceramic powder: 5 to 83 parts;

SiO ₂ ceramic powder: 17 to 95 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

As a preferred solution, the microwave dielectric ceramic composition includes the following components by weight: SrO ceramic powder: 2 to 18 parts;

P ₂ O ₅ ceramic powder: 5 to 80 parts;

SiO ₂ ceramic powder: 41 to 95 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

As a further preferred embodiment, the microwave dielectric ceramic composition includes the following components by weight: SrO ceramic powder: 5 to 16 parts;

P ₂ O ₅ ceramic powder: 15 to 65 parts;

SiO ₂ ceramic powder: 49 to 85 parts;

B ₂ O ₃ ceramic powder: 0.5～3.1 parts;

TiO ₂ ceramic powder: 3 to 8.5 parts.

As a further preferred embodiment, the microwave dielectric ceramic composition includes the following parts by weight of each component: SrO ceramic powder: 10 to 12 parts;

P ₂ O ₅ ceramic powder: 35 to 45 parts;

SiO ₂ ceramic powder: 61 to 69 parts;

B ₂ O ₃ ceramic powder: 1.2 to 1.8 parts;

TiO ₂ ceramic powder: 5.5 to 6.5 parts.

As a preferred solution, the microwave dielectric ceramic composition includes the following components by weight: BaO ceramic powder: 10 to 20 parts;

P ₂ O ₅ ceramic powder: 40 to 83 parts;

SiO ₂ ceramic powder: 17 to 56 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

As a preferred solution, the microwave dielectric ceramic composition includes the following components by weight: BaO ceramic powder: 10 to 15 parts;

P ₂ O ₅ ceramic powder: 40 to 64 parts;

SiO ₂ ceramic powder: 35 to 56 parts;

B ₂ O ₃ ceramic powder: 0 to 1.8 parts;

TiO ₂ ceramic powder: 0 to 6.5 parts.

As a further preferred version, the microwave dielectric ceramic composition includes the following components by weight:

BaO ceramic powder: 13 to 14 parts;

P ₂ O ₅ ceramic powder: 47 to 53 parts;

SiO ₂ ceramic powder: 42 to 47 parts;

B ₂ O ₃ ceramic powder: 0.6~1 part;

TiO ₂ ceramic powder: 4 to 5 parts.

In a second aspect, the present invention relates to a microwave dielectric ceramic material, which includes the aforementioned microwave dielectric ceramic composition and at least one of a dispersant and a binder.

In a third aspect, the present invention relates to an application of the microwave dielectric ceramic material according to the foregoing in the preparation of high-frequency devices.

As a preferred solution, the high-frequency device is any one of a resonator, a filter, an oscillator, a dielectric antenna, and a dielectric substrate.

Compared with the prior art, the present invention has the following beneficial effects:

1. The microwave dielectric ceramic material prepared by the present invention has a low dielectric constant (adjustable in the range of 3.9 to 8.4, more preferably in the range of 5 to 8.40, and the specific value can be adjusted through the formula). The low dielectric constant can be When this ceramic material is used as a substrate for high-frequency digital circuit substrates, it can achieve lower signal delay. At the same frequency, the lower the dielectric constant, the faster the signal propagation speed.

2. The microwave dielectric ceramic material prepared by the present invention has very low dielectric loss (ie, high quality factor, high Qxf; adjustable in the range of 63000 to 85000 GHz, and the specific value can be adjusted through formula and process).

3. The microwave dielectric ceramic material prepared by the present invention has the advantage of near-zero temperature coefficient (adjustable within the range of ±12ppm/℃, preferably within the range of ±10ppm/℃, and the specific value can be adjusted through the formula); so During its application, changes in operating temperature will not affect the operating frequency of the device, and there will be no frequency temperature drift.

4. The microwave dielectric ceramic material prepared by the present invention has an expansion coefficient performance of about 15 ppm/℃ (in the range of 10 to 18 ppm/℃, the specific value can be adjusted through the formula and process). This performance can ensure that the microwave dielectric ceramic material prepared with this material can When the device is installed on the PCB circuit board, it can match the expansion coefficient of the PCB to prevent excessive stress between the PCB and the dielectric device and cause it to fall off or crack.

5. The microwave dielectric ceramic material prepared by the present invention has a wide range of sintering temperature characteristics. It can obtain a high density (96%) at a sintering temperature of 950 to 1450°C. This characteristic can be guaranteed in actual engineering production. Higher yield and reduced investment in equipment.

6. The microwave dielectric ceramic material prepared by the present invention can work stably in the environment due to its high density and non-deliquescent components. The operating temperature range is wide, and each phase can exist stably from low temperature (minus -80℃) to high temperature (not higher than 1450℃).

7. Each component of the microwave dielectric ceramic material prepared by the present invention is non-toxic, cheap and has a low synthesis temperature. This substrate has higher commercial value than other ceramic substrates of the same type in actual production and application.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In the following examples, a microwave dielectric ceramic composition is provided, including the following components by weight:

SrO or BaO ceramic powder: 2 to 20 parts;

P ₂ O ₅ ceramic powder: 5 to 83 parts;

SiO ₂ ceramic powder: 17 to 95 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

In a specific embodiment, the microwave dielectric ceramic composition is SrO-SiO2-P2O5-B2O3-TiO2, including SrO ceramic powder, P2O5 ceramic powder, SiO2 ceramic powder, B2O3 ceramic powder and TiO2 ceramic powder, specifically including the following weight Parts of each component:

SrO ceramic powder: 2 to 18 parts;

P ₂ O ₅ ceramic powder: 5 to 80 parts;

SiO ₂ ceramic powder: 41 to 95 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

In a specific embodiment, the weight parts of the SrO ceramic powder can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 parts or a range between any two values. Preferably, it is 5-16 parts by weight, and more preferably, it is 10-12 parts by weight.

The weight parts of the P ₂ O ₅ ceramic powder can be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 parts or any two of them A range of values between values. Preferably, it is 15-65 parts by weight, and more preferably, it is 35-45 parts by weight.

The weight parts of the SiO ₂ ceramic powder can be 40, 41, 44, 46, 49, 52, 55, 58, 61, 65, 69, 72, 76, 81, 85, 90, 95 parts or any two of them A range of values between values. Preferably, it is 49-85 parts by weight, and more preferably, it is 61-69 parts by weight.

The weight parts of the B ₂ O ₃ ceramic powder can be 0, 0.2, 0.5, 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3.0, 3.1, 3.5, 3.6, 4, 4.2, 4.5, 4.8, 5 parts or a range value between any two of these values. Preferably, the weight part is 0.5-3.1 parts, and more preferably, it is 1.2-1.8 parts by weight.

The weight parts of the TiO ₂ ceramic powder can be 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 parts or a range between any two of these values. Preferably, the weight part is 3-8.5 parts, and more preferably, it is 5.5-6.5 parts by weight.

The microwave dielectric ceramic material prepared by using the microwave dielectric ceramic composition SrO-SiO2-P2O5-B2O3-TiO2 has a dielectric constant ε of 3.92 to 6.13, a quality factor Qxf of 63730 to 82055GHz, and a resonant frequency temperature coefficient Tf of ±11.2ppm/ Within ℃, the expansion coefficient CTE is 13~18ppm/℃. By further using the preferred weight parts of each ceramic powder, the dielectric constant ε is 4.17 to 5.61, the quality factor Qxf is 68060 to 82055GHz, the resonant frequency temperature coefficient Tf is within ±7ppm/℃, and the expansion coefficient CTE is 14 to 18ppm. /℃ performance. By further using more preferred weight parts of each ceramic powder, the dielectric constant ε is less than 5, the quality factor Qxf is more than 80000GHz, the resonant frequency temperature coefficient Tf is within ±2ppm/℃, and the expansion coefficient CTE is 14 to 17ppm/ ℃ performance. As a result, the microwave dielectric ceramic composition has low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and high expansion coefficient.

In another specific embodiment, the microwave dielectric ceramic composition is BaO-SiO2-P2O5-B2O3-TiO2, including BaO ceramic powder, P2O5 ceramic powder, SiO2 ceramic powder, B2O3 ceramic powder and TiO2 ceramic powder, specifically including the following Parts by weight of each component:

BaO ceramic powder: 10 to 20 parts;

P ₂ O ₅ ceramic powder: 40 to 83 parts;

SiO ₂ ceramic powder: 17 to 56 parts;

B ₂ O ₃ ceramic powder: 0 to 5 parts;

TiO ₂ ceramic powder: 0 to 10 parts.

In a specific embodiment, the weight parts of the BaO ceramic powder can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts or a range between any two of them. value. Preferably, it is 10-15 parts by weight, and more preferably, it is 13-14 parts by weight.

The weight parts of the P ₂ O ₅ ceramic powder can be 40, 42, 45, 47, 50, 53, 55, 56, 60, 64, 66, 68, 70, 72, 75, 78, 80 parts or among them A range of values between any two numbers. Preferably, it is 40-64 parts by weight, and more preferably, it is 47-53 parts by weight.

The weight parts of the SiO ₂ ceramic powder can be 17, 19, 22, 24, 26, 28, 30, 32, 35, 37, 39, 42, 44, 47, 50, 53, 56 parts or any two of them A range of values between values. Preferably, it is 35-56 parts by weight, and more preferably, it is 42-47 parts by weight.

The weight parts of the B ₂ O ₃ ceramic powder can be 0, 0.2, 0.5, 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3.0, 3.1, 3.5, 3.6, 4, 4.2, 4.5, 4.8, 5 parts or a range value between any two of these values. Preferably, the weight part is 0 to 1.8 parts, and more preferably, it is 0.6 to 1 part by weight.

The weight parts of the TiO ₂ ceramic powder can be 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 parts or a range between any two of these values. Preferably, the weight part is 0-6.5 parts, and more preferably, it is 4-5 parts by weight.

The microwave dielectric ceramic material prepared using the microwave dielectric ceramic composition BaO-SiO2-P2O5-B2O3-TiO2 has a dielectric constant ε of 5.16 to 8.26, a quality factor Qxf of 61520 to 77040GHz, and a resonant frequency temperature coefficient Tf of ±10ppm/℃. Within the performance, the expansion coefficient CTE is 10~18ppm/℃. By further using the preferred weight parts of each ceramic powder, the dielectric constant ε is 5.16 to 6.44, the quality factor Qxf is 67500 to 77040GHz, the resonant frequency temperature coefficient Tf is within ±9.05ppm/℃, and the expansion coefficient CTE is 10 to 10 18ppm/℃ performance. By further using more preferred weight parts of each ceramic powder, the dielectric constant ε is 6 or less, the quality factor Qxf is 67500GHz or more, the resonant frequency temperature coefficient Tf is within ±7ppm/℃, and the expansion coefficient CTE is 14 to 18ppm/ ℃ performance. As a result, the microwave dielectric ceramic composition has low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and high expansion coefficient.

In a specific embodiment, a microwave dielectric ceramic material is also provided, including the aforementioned microwave dielectric ceramic composition, and other conventional additive components for preparing ceramic materials, such as dispersants, binders, etc., but are not limited to this.

The dispersant is selected from polyacrylic acid resin. The present invention does not specifically limit the type and dosage of the dispersant, and conventional additives can be used to achieve the dispersion effect.

The binder is selected from one of polyvinyl alcohol (PVA) and polyethylene glycol (PEG). The present invention does not specifically limit the type and dosage of the adhesive, and conventional additives can be used to achieve the bonding effect.

In a specific embodiment, a method for preparing microwave dielectric ceramic materials is also provided. The method for preparing microwave dielectric ceramic materials of the present invention can be carried out by using existing conventional methods, and is not particularly limited in the present invention.

In a specific embodiment, the preparation method of the microwave dielectric ceramic material includes the following steps:

(1) Weigh each ceramic powder raw material according to the weight parts of SrO or BaO, SiO ₂ , P ₂ O ₅ , B ₂ O ₃ and TiO ₂ , and add the corresponding proportion according to the addition ratio of BaO, SrO and P ₂ O ₅ The raw materials are BaCO ₃ , SrCO ₃ and NH ₄ H ₂ PO ₄ ; the purity of each ceramic powder is above 99.9%.

(2) Use SrCO ₃ or BaCO ₃ , NH ₄ H ₂ PO ₄ and dispersant as materials for ball milling to obtain a mixed slurry;

(3) Dry the mixed slurry obtained in step (2) and perform pretreatment between 700 and 1000°C to obtain pretreated powder;

(4) Add SiO ₂ , TiO ₂ , B ₂ O ₃ and dispersant to the pretreated powder obtained in step (3) twice and ball-mill to obtain a mixed slurry that is dried, and then a binder is added for granulation;

(5) Shape the granulated material obtained in step (4) to obtain a ceramic blank;

(6) The ceramic blank obtained in step (5) is degreased, sintered, and then cooled in the furnace to obtain the required microwave dielectric ceramic material.

In a specific embodiment, in step (2), when the ceramic powder is a mixed slurry obtained from SrO and P ₂ O ₅ , the pretreatment temperature is 850 to 1000°C; the ceramic powder is BaO, P ₂ When the mixed slurry is obtained from O ₅ , the pretreatment temperature is 700 to 850°C.

In step (5), the molding process is selected from tape casting, spray drying or dry pressing molding.

In step (6), the degreasing temperature is 550-650°C;

When the ceramic green body is obtained from SrO and other ceramic powders, the sintering temperature used is 950-1450°C and the heat preservation is 1-5 hours; when the ceramic green body is obtained from BaO and other ceramic powders, the sintering temperature used is 950-1450℃. 1350℃, heat preservation 1-5h;

The sintering temperature rise rate is 2-8°C/min.

Example

The technical solution of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Unless otherwise stated, all reagents and raw materials used can be purchased commercially. Experimental methods that do not indicate specific conditions in the following examples should be selected according to conventional methods and conditions, or according to product specifications.

Example 1

This embodiment provides a microwave dielectric ceramic composition, including the following components by weight:

SrO ceramic powder a: 2≤a≤18,

P ₂ O ₅ ceramic powder c: 5≤c≤80,

SiO ₂ ceramic powder d: 41≤d≤95,

B ₂ O ₃ ceramic powder e: 0≤e≤5,

TiO ₂ ceramic powder f: 0≤f≤10.

The method for preparing microwave dielectric ceramics using the microwave dielectric ceramic composition includes the following steps:

(1) Weigh each ceramic powder raw material according to the above weight parts: SrCO ₃ , SiO ₂ , NH ₄ H ₂ PO ₄ , B ₂ O ₃ , TiO ₂ (wherein add the corresponding SrO and P ₂ O ₅ in the proportion Raw materials SrCO ₃ , NH ₄ H ₂ PO ₄ );

(2) Pour SrCO ₃ , NH ₄ H ₂ PO ₄ and an appropriate amount of dispersant (polyacrylic acid resin) as materials into the resin ball mill tank, add alcohol and ZrO ₂ balls, and the weight ratio of materials, ZrO ₂ balls and alcohol is 1:4:0.8, ball mill for 24 hours to get mixed slurry;

(3) Dry the mixed slurry obtained in step (2) and perform pretreatment at 950°C to obtain pretreated powder;

(4) Add SiO ₂ , TiO ₂ , B ₂ O ₃ and an appropriate amount of dispersant (polyacrylic acid resin) to the pretreated powder obtained in step (3) twice and ball-mill for 24 hours. The mixed slurry is dried and then added P ₂ O ₅ weight 8wt% polyvinyl alcohol (PVA) solution with a mass fraction of 5% is granulated;

(5) Dry-press the granulated material obtained in step (4) to obtain a ceramic blank;

(6) Put the ceramic blank obtained in step (5) into a muffle furnace after degreasing at 600°C, raise the temperature to 1200°C at 5°C/min, keep it for 2 hours, and then cool it with the furnace to obtain the required microwave dielectric ceramic material. .

The specific prepared microwave dielectric ceramic materials 1-16 and the proportions by weight of each ceramic powder used and the performance measurement results are shown in Table 1. Use a microwave network analyzer to test the microwave dielectric properties (N5242A, Agilent, Palo Alto, CA). The dielectric constant ε is tested using the Hakki–Coleman method, the test frequency is 18-23GHz, and the TE ₀₁₁ resonance mode is selected; quality factors The test of Qxf is carried out using the resonant cavity method. The test frequency is 10GHz and the TE _01δ resonance mode is selected. The temperature coefficient of the resonant frequency τ _f is tested using the same method as the dielectric constant ε. The parallel plate open resonant strong cavity is put into the high and low temperature test. Box, test temperature range (-25-80℃), measure the change of resonant frequency with temperature; the expansion coefficient CTE is tested using NETZSCH STA 449C, Netzsch Instrument, Germany.

Table 1

It can be seen from the results in Table 1 that the microwave dielectric ceramic materials 1-16 prepared in this embodiment have the properties of low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and high expansion coefficient (dielectric constant ε is 3.92 ~6.13, quality factor Qxf is 63730~82055GHz, resonant frequency temperature coefficient Tf is within ±11.2ppm/℃, expansion coefficient CTE is 13~18ppm/℃). The microwave dielectric ceramic material 3-13 prepared therein has better overall performance than other embodiments (dielectric constant ε is 4.17~5.61, quality factor Qxf is 68060~82055GHz, and resonant frequency temperature coefficient Tf is within ±7ppm/℃ , expansion coefficient CTE is 14~18ppm/℃). In particular, the prepared microwave dielectric ceramic materials 7-9 have optimal comprehensive properties (dielectric constant ε is less than 5, quality factor Qxf is more than 80000GHz, resonant frequency temperature coefficient Tf is within ±2ppm/℃, expansion coefficient CTE is 14～17ppm/℃).

Example 2

This embodiment provides a microwave dielectric ceramic composition, including the following components by weight:

BaO ceramic powder b: 2≤b≤18

P ₂ O ₅ ceramic powder c: 40≤c≤83

SiO ₂ ceramic powder d: 41≤d≤95

B ₂ O ₃ ceramic powder e: 0≤e≤5

TiO ₂ ceramic powder f: 0≤f≤10.

The method for preparing microwave dielectric ceramics using the microwave dielectric ceramic composition includes the following steps:

(1) Weigh each ceramic powder raw material in parts by weight: BaCO ₃ , SiO ₂ , NH ₄ H ₂ PO ₄ , B ₂ O ₃ , TiO ₂ (add the corresponding raw materials according to the addition ratio of BaO and P ₂ O ₅ BaCO ₃ , NH ₄ H ₂ PO ₄ );

(2) Pour BaCO ₃ , NH ₄ H ₂ PO ₄ and an appropriate amount of dispersant (polyacrylic acid resin) as materials into a resin ball mill tank, add alcohol and ZrO ₂ balls, and the weight ratio of materials, ZrO ₂ balls and alcohol is 1:4:0.8, ball mill for 24h to get mixed slurry;

(3) Dry the mixed slurry obtained in step (2) and perform pretreatment at 800°C to obtain pretreated powder;

(4) Add SiO ₂ , TiO ₂ , B ₂ O ₃ and an appropriate amount of dispersant (polyacrylic acid resin) to the pretreated powder obtained in step (3) for a second time and ball-mill for 24 hours to obtain a mixed slurry and dry it, then add P ₂ O ₅ weight 8wt% polyvinyl alcohol (PVA) solution with a mass fraction of 5% is granulated;

(5) Dry-press the granulated material obtained in step (4) to obtain a ceramic blank;

(6) Put the ceramic blank obtained in step (5) into a muffle furnace after degreasing at 600°C, raise the temperature to 1100°C at 5°C/min, keep it for 2 hours, and then cool it with the furnace to obtain the required microwave dielectric ceramic material. .

The specific prepared microwave dielectric ceramic materials 17-32 and the proportions by weight of each ceramic powder used and the measurement results of each performance are shown in Table 2. The method for measuring each performance is the same as in Example 1.

Table 2

It can be seen from the results in Table 2 that the microwave dielectric ceramic materials 17-32 prepared in this embodiment have the properties of low dielectric constant, high quality factor, near-zero resonant frequency temperature coefficient and high expansion coefficient (dielectric constant ε is 5.16 ~8.26, quality factor Qxf is 61520~77040GHz, resonant frequency temperature coefficient Tf is within ±10ppm/℃, and expansion coefficient CTE is 10~18ppm/℃). The microwave dielectric ceramic materials 17-25 prepared therein have better comprehensive properties than other embodiments (dielectric constant ε is 5.16~6.44, quality factor Qxf is 67500~77040GHz, and resonant frequency temperature coefficient Tf is ±9.05ppm/℃ Within, the expansion coefficient CTE is 10~18ppm/℃). In particular, the prepared microwave dielectric ceramic materials 20-22 have better comprehensive properties (dielectric constant ε is less than 6, quality factor Qxf is more than 67500GHz, resonant frequency temperature coefficient Tf is within ±7ppm/℃, expansion coefficient CTE is 14～18ppm/℃).

In addition, the densities of the microwave dielectric ceramic materials prepared in the above-mentioned Examples 1 and 2 are both 96% and above, indicating high densities.

The above descriptions are only embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the description of the present invention, or directly or indirectly applied in other related technical fields, shall be regarded as equivalent. The principle is included in the patent protection scope of the present invention.

Claims (7)

1. The microwave dielectric ceramic composition is characterized by comprising the following components in parts by weight:

SrO ceramic powder: 5-16 parts;

P ₂ O ₅ ceramic powder: 15-65 parts;

SiO ₂ ceramic powder: 49-85 parts;

B ₂ O ₃ ceramic powder: 0.5 to 3.1 parts;

TiO ₂ ceramic powder: 3 to 8.5 portions; or comprises the following components in parts by weight:

BaO ceramic powder: 10-20 parts;

P ₂ O ₅ ceramic powder: 40-83 parts;

SiO ₂ ceramic powder: 17-56 parts;

B ₂ O ₃ ceramic powder: 0-5 parts;

TiO ₂ ceramic powder: 0-10 parts.

2. The microwave dielectric ceramic composition according to claim 1, comprising the following components in parts by weight:

SrO ceramic powder: 10-12 parts;

P ₂ O ₅ ceramic powder: 35-45 parts;

SiO ₂ ceramic powder: 61-69 parts;

B ₂ O ₃ ceramic powder: 1.2 to 1.8 portions;

TiO ₂ ceramic powder: 5.5 to 6.5 portions.

3. The microwave dielectric ceramic composition according to claim 1, comprising the following components in parts by weight:

BaO ceramic powder: 10-15 parts;

P ₂ O ₅ ceramic powder: 40-64 parts;

SiO ₂ ceramic powder: 35-56 parts;

B ₂ O ₃ ceramic powder: 0 to 1.8 portions;

TiO ₂ ceramic powder: 0 to 6.5 portions.

4. A microwave dielectric ceramic composition according to claim 3, comprising the following components in parts by weight:

BaO ceramic powder: 13-14 parts;

P ₂ O ₅ ceramic powder: 47-53 parts;

SiO ₂ ceramic powder: 42-47 parts;

B ₂ O ₃ ceramic powder: 0.6-1 part;

TiO ₂ ceramic powder: 4-5 parts.

5. A microwave dielectric ceramic material, comprising the microwave dielectric ceramic composition according to any one of claims 1 to 4, and further comprising at least one of a dispersant and a binder.

6. Use of a microwave dielectric ceramic material according to claim 5 for the preparation of high frequency devices.

7. The use of claim 6, wherein the high frequency device is any one of a resonator, a filter, an oscillator, a dielectric antenna, a dielectric substrate.