Zirconium pyrophosphate multiphase ceramic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of microwave dielectric materials, and provides a zirconium pyrophosphate composite ceramic material as well as a preparation method and application thereof. The zirconium pyrophosphate multiphase ceramic material comprises zirconium pyrophosphate serving as a main crystal phase and alkali metal zirconium phosphate serving as a second crystal phase. By introducing the alkali metal zirconium phosphate, the normal-temperature heat conductivity coefficient of the zirconium pyrophosphate composite ceramic material is improved, and the heat dissipation effect of the zirconium pyrophosphate composite ceramic material serving as a substrate material is improved. The invention also provides a preparation method of the zirconium pyrophosphate composite ceramic material according to the technical scheme, alkali metal is introduced in the form of alkali metal fluoride, the alkali metal fluoride can form a liquid phase at the sintering temperature, and the liquid phase can promote the sintering effect, so that the sintering temperature is reduced, and the service life of the ceramic material is prolonged. According to the zirconium pyrophosphate composite ceramic material, low-temperature sintering can be achieved by adding the alkali metal fluoride, fluorine in the alkali metal fluoride can be removed after sintering, and redundant impurities cannot be introduced into the zirconium pyrophosphate composite ceramic material.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave dielectric materials, and particularly relates to a zirconium pyrophosphate composite ceramic material, a preparation method thereof and an application thereof. Background Art

[0002] In recent years, the development of aircraft has required that radome materials develop towards high reliability. Compared with organic materials, ceramic materials have more excellent mechanical properties, thermal stability and service life. Zirconium pyrophosphate ceramics themselves have the advantages of low dielectric constant and low dielectric loss, which well meet the requirements of the wave transmission performance of radomes.

[0003] The related prior art discloses a preparation method of a zirconium pyrophosphate composite ceramic material. By adding rare earth oxides, magnesium oxide, molybdenum oxide and vanadium oxide, the zirconium pyrophosphate composite ceramic material is prepared by a solid-phase method. The obtained zirconium pyrophosphate composite ceramic material has a low room-temperature thermal conductivity, only 0.15 - 0.42 W / (m·K). Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a zirconium pyrophosphate composite ceramic material, a preparation method thereof and an application thereof. The zirconium pyrophosphate composite ceramic material provided by the present invention has a high room-temperature thermal conductivity.

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

[0006] The present invention provides a zirconium pyrophosphate composite ceramic material, including a main crystal phase and a second crystal phase. The main crystal phase is zirconium pyrophosphate, and the second crystal phase is alkali metal zirconium phosphate.

[0007] Preferably, the alkali metal in the alkali metal zirconium phosphate is lithium, sodium or potassium.

[0008] The present invention also provides a preparation method of the zirconium pyrophosphate composite ceramic material according to the above technical solution, including the following steps:

[0009] Mix zirconium pyrophosphate powder and alkali metal fluoride powder, and grind to obtain ceramic powder;

[0010] Subject the ceramic powder to aging, granulation and molding in sequence to obtain a green body;

[0011] Sinter the green body to obtain the zirconium pyrophosphate composite ceramic material.

[0012] Preferably, the mass of the alkali metal fluoride powder is greater than or equal to 1% of the mass of the zirconium pyrophosphate powder;

[0013] The alkali metal fluoride powder is lithium fluoride powder, sodium fluoride powder or potassium fluoride powder;

[0014] The purity of the alkali metal fluoride powder is greater than or equal to 99.0%, and the particle size is less than or equal to 0.1 mm.

[0015] Preferably, the preparation method of the zirconium pyrophosphate powder comprises the following steps:

[0016] Heat the zirconium hydrogen phosphate powder to obtain the zirconium pyrophosphate powder;

[0017] The purity of the zirconium hydrogen phosphate powder is greater than or equal to 99.0%, and the particle size is less than or equal to 10 μm;

[0018] The heating temperature is 700 - 1000 °C, and the heat preservation time is 1 - 3 h;

[0019] The heating is carried out under air atmosphere and normal pressure conditions.

[0020] Preferably, the grinding method is wet grinding, the medium of the wet grinding is water, the grinding balls of the wet grinding are zirconium balls, the rotation speed of the wet grinding is 300 - 450 rpm, and the time is 3 - 5 h.

[0021] Preferably, the aging reagent is an aqueous solution of polyvinyl alcohol, the concentration of the aqueous solution of polyvinyl alcohol is 4 wt%, and the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:1 - 2;

[0022] The aging time is 18 - 30 h, and the aging is carried out under static and sealed conditions.

[0023] Preferably, the forming includes mechanical pressing and cold isostatic pressing in sequence. The pressure of the mechanical pressing is 10 - 50 MPa, and the pressure maintaining time is 0.5 - 2 min; the pressure of the cold isostatic pressing is 100 - 300 MPa, and the pressure maintaining time is 1 - 3 min.

[0024] Preferably, the sintering temperature is 800 - 1000 °C, and the heating rate to the sintering temperature is 5 - 10 °C / min; the heat preservation time of the sintering is 1 - 5 h;

[0025] The sintering is carried out under air atmosphere and normal pressure conditions.

[0026] The present invention also provides the application of the zirconium pyrophosphate composite ceramic material described in the above technical solution or the zirconium pyrophosphate composite ceramic material prepared by the preparation method described in the above technical solution in microwave mobile communication.

[0027] The present invention provides a zirconium pyrophosphate composite ceramic material. The zirconium pyrophosphate composite ceramic material provided by the present invention includes a main crystal phase and a second crystal phase. The main crystal phase is zirconium pyrophosphate, and the second crystal phase is alkali metal zirconium phosphate. The introduction of the second crystal phase of alkali metal zirconium phosphate improves the room-temperature thermal conductivity of the zirconium pyrophosphate composite ceramic material, which is beneficial to improving the heat dissipation effect of the zirconium pyrophosphate composite ceramic material used as a substrate material. The data of the examples show that the room-temperature thermal conductivity of the zirconium pyrophosphate composite ceramic material obtained by the present invention is 1.6 - 2.5 W / (m·K).

[0028] The present invention also provides a preparation method of the zirconium pyrophosphate composite ceramic material described in the above technical solution. The preparation method provided by the present invention has simple process, short production cycle and environmental friendliness. At the same time, the alkali metal is introduced in the form of alkali metal fluoride. Since the melting point of the alkali metal fluoride is 800 - 1000 °C, when the alkali metal is introduced, the alkali metal fluoride can form a liquid phase at the sintering temperature, and the liquid phase can promote the sintering effect, thereby reducing the sintering temperature. That is, the alkali metal fluoride can achieve low-temperature sintering, and the fluorine can be removed after sintering without introducing extra impurities into the zirconium pyrophosphate composite ceramic material. Description of the Drawings

[0029] Figure 1 XRD pattern of the zirconium pyrophosphate composite ceramic material obtained in Example 5;

[0030] Figure 2 SEM image of the zirconium pyrophosphate composite ceramic material obtained in Example 5;

[0031] Figure 3 SEM image of the zirconium pyrophosphate composite ceramic material obtained in Example 6. Detailed Embodiments

[0032] The present invention provides a zirconium pyrophosphate composite ceramic material, including a main crystal phase and a second crystal phase. The main crystal phase is zirconium pyrophosphate, and the second crystal phase is alkali metal zirconium phosphate.

[0033] The zirconium pyrophosphate composite ceramic material provided by the present invention includes a main crystal phase, and the main crystal phase is zirconium pyrophosphate (ZrP2O7).

[0034] The zirconium pyrophosphate composite ceramic material provided by the present invention includes a second crystal phase, and the second crystal phase is alkali metal zirconium phosphate (MZr2(PO4)3). The alkali metal M in the alkali metal zirconium phosphate is lithium, sodium or potassium. In the present invention, the alkali metal zirconium phosphate is specifically lithium zirconium phosphate (LiZr2(PO4)3), sodium zirconium phosphate (NaZr2(PO4)3) or potassium zirconium phosphate (KZr2(PO4)3).

[0035] The present invention also provides a method for preparing the zirconium pyrophosphate composite ceramic material described in the above technical solution, comprising the following steps:

[0036] Mix zirconium pyrophosphate powder and alkali metal fluoride powder, and successively carry out wet grinding and drying to obtain ceramic powder;

[0037] Successively carry out aging, granulation and molding on the ceramic powder to obtain a green body;

[0038] Sinter the green body to obtain the zirconium pyrophosphate composite ceramic material.

[0039] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0040] The present invention mixes zirconium pyrophosphate powder and alkali metal fluoride powder, and grinds them to obtain ceramic powder.

[0041] In the present invention, the preparation method of the zirconium pyrophosphate powder preferably comprises the following steps: heating zirconium hydrogen phosphate powder to obtain the zirconium pyrophosphate powder. In the present invention, the purity of the zirconium hydrogen phosphate powder is preferably greater than or equal to 99.0%, and the particle size is preferably less than or equal to 10 μm. In the present invention, the heating temperature is preferably 700-1000 °C, specifically preferably 700 °C, 750 °C, 800 °C, 850 °C, 900 °C, 950 °C or 1000 °C; the heat preservation time is preferably 1-3 h, specifically preferably 1 h, 1.5 h, 2 h, 2.5 h or 3 h; the heating is preferably carried out under air atmosphere and normal pressure conditions. In the present invention, the zirconium hydrogen phosphate powder can form zirconium pyrophosphate powder after heating; at the same time, using zirconium hydrogen phosphate powder to prepare zirconium pyrophosphate powder has the effect of safety and environmental protection compared with using phosphoric acid and ammonium dihydrogen phosphate as raw materials to prepare zirconium pyrophosphate. At the same time, by controlling the heating temperature to 700-1000 °C, the present invention can make the zirconium hydrogen phosphate powder decompose sufficiently to form zirconium pyrophosphate powder.

[0042] In the present invention, the alkali metal fluoride powder is preferably lithium fluoride powder, sodium fluoride powder or potassium fluoride powder. In the present invention, the purity of the alkali metal fluoride powder is preferably greater than or equal to 99.0%, and the particle size is less than or equal to 0.1 mm. In the present invention, introducing alkali metal with lithium fluoride powder, sodium fluoride powder or potassium fluoride powder as raw materials, the melting points of the above alkali metal fluorides are 800-1000 °C. When the sintering temperature reaches the melting point of the alkali metal fluoride, the formed liquid phase can promote the sintering effect, which is beneficial to realize low-temperature sintering; that is, a zirconium pyrophosphate composite ceramic material with good density can be obtained at a low temperature (800-1000 °C); at the same time, fluorine can be removed after sintering and no extra impurities will be introduced.

[0043] In the present invention, the mass of the alkali metal fluoride powder is preferably greater than or equal to 1% of the mass of the zirconium pyrophosphate powder, more preferably 1 - 12%, and specifically preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11% or 12%. In the present invention, with the increase of the addition amount of the alkali metal fluoride, it is beneficial to further reduce the sintering temperature; the addition amount of the alkali metal fluoride powder in the present invention is controlled to be 1 - 12% of the mass of the zirconium pyrophosphate powder, which not only ensures the reduction of the sintering temperature, but also ensures that the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material remains within 10, and the room-temperature dielectric loss is within 1×10 -2 (at a frequency of 10 GHz).

[0044] In the present invention, the grinding method is preferably wet grinding, the medium for wet grinding is preferably water, and the water is preferably deionized water; the addition amount of the water is 150 - 250% of the total mass of the zirconium pyrophosphate powder and the alkali metal fluoride, specifically preferably 150%, 200% or 250%. In the present invention, the grinding balls for wet grinding are preferably zirconia balls, and the diameter of the zirconia balls is preferably 0.1 - 10 mm, specifically preferably 0.1 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. In the present invention, the rotation speed of wet grinding is preferably 300 - 450 rpm, more preferably 300 rpm, 350 rpm, 400 rpm or 450 rpm; the time is preferably 3 - 5 h, specifically preferably 3 h, 4 h or 5 h. In the present invention, the wet grinding is preferably carried out on a planetary ball mill.

[0045] When the grinding method is wet grinding, after the wet grinding, the present invention preferably further includes drying and sieving in sequence; the present invention does not specifically limit the temperature and time of the drying, as long as the medium for wet grinding can be completely removed. In the present invention, the aperture of the sieve for sieving is preferably 500 mesh.

[0046] After obtaining the ceramic powder, the present invention subjects the ceramic powder to aging, granulation and molding in sequence to obtain a green body.

[0047] In the present invention, the aged reagent is preferably an aqueous solution of polyvinyl alcohol, and the concentration of the aqueous solution of polyvinyl alcohol is preferably 4 wt%. In the present invention, the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is preferably 20:1 to 2, specifically preferably 20:1, 20:1.5 or 20:2. In the present invention, the aging time is preferably 18 to 30 h, specifically preferably 18 h, 20 h, 22 h, 24 h, 26 h, 28 h or 30 h; the aging is preferably carried out under static and sealed conditions. In a specific embodiment of the present invention, the aging preferably includes the following steps: mixing the ceramic powder and the aqueous solution of polyvinyl alcohol, and then aging under static and sealed conditions.

[0048] In the present invention, the granulation method is preferably crushing, and the present invention does not make specific limitations on the crushing method. As long as the crushed material can pass through a 200-mesh sieve.

[0049] In the present invention, the molding preferably includes mechanical pressing molding and cold isostatic pressing molding in sequence. The pressure of the mechanical pressing molding is preferably 10 to 50 MPa, specifically preferably 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa or 50 MPa; the pressure holding time is preferably 0.5 to 2 min, specifically preferably 0.5 min, 1 min, 1.5 min or 2 min. In the present invention, the pressure of the cold isostatic pressing molding is preferably 100 to 300 MPa, specifically preferably 100 MPa, 150 MPa, 200 MPa, 250 MPa or 300 MPa; the pressure holding time is preferably 1 to 3 min, specifically preferably 1 min, 1.5 min, 2 min, 2.5 min or 3 min.

[0050] After obtaining the green body, the present invention sinters the green body to obtain the zirconium pyrophosphate composite ceramic material.

[0051] In the present invention, the sintering temperature is preferably 800 to 1000 °C, specifically preferably 800 °C, 850 °C, 900 °C, 950 °C or 1000 °C; the heating rate for heating to the sintering temperature is preferably 5 to 10 °C / min, specifically preferably 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min or 10 °C / min; the holding time for sintering is preferably 1 to 5 h, specifically preferably 1 h, 2 h, 3 h, 4 h or 5 h. In the present invention, the sintering is preferably carried out under air atmosphere and normal pressure conditions. In the present invention, the sintering is preferably carried out in an electric resistance furnace.

[0052] In the present invention, an alkali metal is introduced by using an alkali metal fluoride powder. While successfully introducing the alkali metal, the sintering temperature is effectively reduced. Sintering can be achieved at only 800 - 1000 °C, and a zirconium pyrophosphate composite ceramic material with high density can be obtained.

[0053] The preparation method provided by the present invention has simple raw materials, low cost, and stable process, and the crystal phase in the obtained zirconium pyrophosphate composite ceramic material is stable.

[0054] The present invention also provides the application of the zirconium pyrophosphate composite ceramic material described in the above technical solution or the zirconium pyrophosphate composite ceramic material prepared by the preparation method described in the above technical solution in microwave mobile communication.

[0055] The present invention does not specifically limit the application method of the zirconium pyrophosphate composite ceramic material, and those skilled in the art can set it according to actual needs.

[0056] The following examples are used to illustrate in detail the zirconium pyrophosphate composite ceramic material, its preparation method, and application provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0057] The purity of the zirconium hydrogen phosphate powder used in the following examples is 99.0%, and the particle size is less than or equal to 10 μm; the purity of the lithium fluoride powder is 99.0%, and the particle size is ≤0.1 mm; the purity of the potassium fluoride powder is 99.9%, and the particle size is ≤0.1 mm.

[0058] Example 1

[0059] A preparation method of a zirconium pyrophosphate composite ceramic material comprises the following steps:

[0060] Step 1: Under an air atmosphere and normal pressure conditions, heat the zirconium hydrogen phosphate powder to 800 °C and keep it warm for 2 h to obtain zirconium pyrophosphate powder.

[0061] Step 2: According to the mass ratio of zirconium pyrophosphate powder to lithium fluoride powder being 1:0.01, mix the zirconium pyrophosphate powder and the fluoride powder, place them in a planetary ball mill for wet grinding. The wet grinding medium is deionized water (the mass of deionized water is 150% of the total mass of zirconium pyrophosphate powder and lithium fluoride powder), the grinding balls are zirconia balls (diameter 4 mm), the rotation speed of the planetary ball mill is 300 rpm, and the wet grinding time is 4 h. Pass the wet grinding material through a 500 - mesh sieve, and then dry it to obtain ceramic powder.

[0062] Step 3: Add an aqueous solution of polyvinyl alcohol with a concentration of 4 wt% to the ceramic powder. The mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:1. Let it age for 20 h under static and sealed conditions. Then crush it and sieve it through a 200-mesh sieve to obtain ceramic particles. Press the ceramic particles at 10 MPa for 1 min, and then subject the green body after pressing to cold isostatic pressing at 150 MPa for 2 min to obtain a green compact.

[0063] Step 4: Under an air atmosphere and normal pressure conditions, place the green compact in an electric resistance furnace and heat it to 1000 °C at a heating rate of 7 °C / min, and hold for 2 h to obtain the zirconium pyrophosphate composite ceramic material.

[0064] The obtained zirconium pyrophosphate composite ceramic material is analyzed by X-ray diffraction. The main crystal phase is zirconium pyrophosphate, and the second crystal phase is lithium zirconium phosphate.

[0065] Use GB / T 5594.4-2015 to detect the room-temperature dielectric constant and room-temperature dielectric loss of the obtained zirconium pyrophosphate composite ceramic material.

[0066] Use ISO 22007-2 to detect the room-temperature thermal conductivity of the obtained zirconium pyrophosphate composite ceramic material.

[0067] The results are as follows: The room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material is 7.1 (at a frequency of 10 GHz); the room-temperature dielectric loss is 1.3×10 -3 (at a frequency of 10 GHz), the room-temperature thermal conductivity is 1.8 W / (m·K); the relative density is 92.3%.

[0068] Example 2

[0069] A preparation method of a zirconium pyrophosphate composite ceramic material, the steps are as follows:

[0070] Step 1: Under an air atmosphere and normal pressure conditions, heat the zirconium hydrogen phosphate powder to 900 °C and hold for 1 h to obtain zirconium pyrophosphate powder.

[0071] Step 2: Mix the zirconium pyrophosphate powder and potassium fluoride powder according to a mass ratio of 1:0.05, place them in a planetary ball mill for wet grinding. The wet grinding medium is deionized water (the mass of deionized water is 250% of the total mass of the zirconium pyrophosphate powder and potassium fluoride powder), the grinding balls are zirconium balls (diameter 4 mm), the rotation speed of the planetary ball mill is 450 rpm, and the wet grinding time is 5 h. Sieve the wet grinding material through a 500-mesh sieve, and then dry it to obtain ceramic powder.

[0072] Step 3: Add an aqueous solution of polyvinyl alcohol with a concentration of 4 wt% to the ceramic powder. Here, the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:2. Age for 18 h under static and sealed conditions; then crush and pass through a 200-mesh sieve to obtain ceramic particles; press the ceramic particles into shape at 30 MPa for 2 min, and then subject the green body after mechanical pressing to cold isostatic pressing at 200 MPa for 3 min to obtain a green compact.

[0073] Step 4: Under air atmosphere and normal pressure conditions, place the green compact in an electric resistance furnace and heat it to 900 °C at a heating rate of 5 °C / min, and hold for 3 h to obtain the zirconium pyrophosphate composite ceramic material.

[0074] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as follows: the main crystal phase was zirconium pyrophosphate, and the second crystal phase was potassium zirconium phosphate.

[0075] The obtained zirconium pyrophosphate composite ceramic material was detected by the method of Example 1, and the results were as follows: the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 7.6 (frequency: 10 GHz); the room-temperature dielectric loss was 1.1×10 -3 (frequency: 10 GHz); the room-temperature thermal conductivity was 1.6 W / (m·K); the relative density was 93.5%.

[0076] Example 3

[0077] A preparation method of a zirconium pyrophosphate composite ceramic material is as follows:

[0078] Step 1: Under air atmosphere and normal pressure conditions, heat the zirconium hydrogen phosphate powder to 900 °C and hold for 2 h to obtain zirconium pyrophosphate powder.

[0079] Step 2: Mix the zirconium pyrophosphate powder and lithium fluoride powder according to a mass ratio of 1:0.06, place them in a planetary ball mill for wet milling, the wet milling medium is deionized water (the mass of deionized water is 200% of the total mass of the zirconium pyrophosphate powder and lithium fluoride powder), the grinding balls are zirconium balls (diameter: 4 mm), the rotation speed of the planetary ball mill is 400 rpm, and the wet milling time is 4 h. Pass the wet milled material through a 500-mesh sieve, and then dry it to obtain ceramic powder.

[0080] Step 3: Add an aqueous solution of polyvinyl alcohol with a concentration of 4 wt% to the ceramic powder. Here, the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:1. Age for 18 h under static and sealed conditions; then crush and pass through a 200-mesh sieve to obtain ceramic particles; press the ceramic particles into shape at 10 MPa for 1.5 min, and then subject the green body after mechanical pressing to cold isostatic pressing at 100 MPa for 2.5 min to obtain a green compact.

[0081] Step 4: Under an air atmosphere and normal pressure conditions, place the green body in a resistance furnace and heat it at a heating rate of 10 °C / min to 900 °C, then hold the temperature for 2 h to obtain the zirconium pyrophosphate composite ceramic material.

[0082] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as follows: the main crystal phase was zirconium pyrophosphate, and the second crystal phase was lithium zirconium phosphate.

[0083] The obtained zirconium pyrophosphate composite ceramic material was detected by the method of Example 1, and the results were as follows: the room temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 8.7 (at a frequency of 10 GHz); the room temperature dielectric loss was 1.1×10 -3 (at a frequency of 10 GHz); the room temperature thermal conductivity was 2.3 W / (m·K); the relative density was 95.2%.

[0084] Example 4

[0085] A preparation method of a zirconium pyrophosphate composite ceramic material is as follows:

[0086] Step 1: Under an air atmosphere and normal pressure conditions, heat the zirconium hydrogen phosphate powder to 1000 °C and hold the temperature for 3 h to obtain the zirconium pyrophosphate powder.

[0087] Step 2: According to the mass ratio of zirconium pyrophosphate powder to lithium fluoride powder being 1:0.12, mix the zirconium pyrophosphate powder and the lithium fluoride powder, place them in a planetary ball mill for wet milling. The wet milling medium is deionized water (the mass of deionized water is 200% of the total mass of the zirconium pyrophosphate powder and the lithium fluoride powder), the grinding balls are zirconium balls (diameter 4 mm), the rotation speed of the planetary ball mill is 350 rpm, and the wet milling time is 5 h. Pass the wet milled material through a 500-mesh sieve, and then dry it to obtain the ceramic powder.

[0088] Step 3: Add an aqueous solution of polyvinyl alcohol with a concentration of 4 wt% to the ceramic powder, where the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:1.5. Under the conditions of standing and sealing, let it age for 30 h; then crush it and pass it through a 200-mesh sieve to obtain ceramic particles; press the ceramic particles at 40 MPa on a mechanical press for 0.5 min, and then perform cold isostatic pressing on the initially pressed green body under the condition of 300 MPa for 1 min to obtain the green body.

[0089] Step 4: Under an air atmosphere and normal pressure conditions, place the green body in a resistance furnace and heat it at a heating rate of 6 °C / min to 800 °C, then hold the temperature for 1 h to obtain the zirconium pyrophosphate composite ceramic material.

[0090] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as follows: the main crystal phase was zirconium pyrophosphate, and the second crystal phase was lithium zirconium phosphate.

[0091] The method of Example 1 was used to detect the obtained zirconium pyrophosphate composite ceramic material, and the results were as follows: the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 9.3 (frequency 10 GHz); the room-temperature dielectric loss was 0.8×10 -3 (frequency 10 GHz); the room-temperature thermal conductivity was 2.5 W / (m·K); the relative density was 94.7%.

[0092] Example 5

[0093] The difference from Example 3 was that in Step 4, the sintering temperature was 800 °C.

[0094] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as Figure 1 shown. It could be seen from Figure 1 the results that the main crystal phase was zirconium pyrophosphate and the second crystal phase was lithium zirconium phosphate.

[0095] The method of Example 1 was used to detect the obtained zirconium pyrophosphate composite ceramic material, and the results were as follows: the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 8.4 (frequency 10 GHz); the room-temperature dielectric loss was 1.2×10 -3 (frequency 10 GHz); the room-temperature thermal conductivity was 2.2 W / (m·K); the relative density was 93.9%.

[0096] Figure 2 Fig. shows the SEM image of the zirconium pyrophosphate composite ceramic material obtained in Example 5. It could be seen from Figure 2 the image that the sample of this example was heat-treated at 800 °C and sintered to densification.

[0097] Example 6

[0098] The difference from Example 5 was that in Step 2, the mass ratio of zirconium pyrophosphate powder to lithium fluoride powder was 1:0.04.

[0099] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as follows: the main crystal phase was zirconium pyrophosphate and the second crystal phase was lithium zirconium phosphate.

[0100] The method of Example 1 was used to detect the obtained zirconium pyrophosphate composite ceramic material, and the results were as follows: the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 7.8 (frequency 10 GHz); the room-temperature dielectric loss was 1.5×10 -3 (frequency 10 GHz); the room-temperature thermal conductivity was 1.9 W / (m·K); the relative density was 92.1%.

[0101] Figure 3 Fig. shows the SEM image of the zirconium pyrophosphate composite ceramic material obtained in Example 6. It could be seen from Figure 3 the image that the sample of this example was sintered to densification.

[0102] Example 7

[0103] The difference from Example 2 is that in Step 2, potassium fluoride powder is replaced with sodium fluoride powder, and the others are the same as in Example 2.

[0104] The obtained zirconium pyrophosphate composite ceramic material was analyzed by X-ray diffraction, and the results were as follows: the main crystal phase was zirconium pyrophosphate, and the second crystal phase was sodium zirconium phosphate.

[0105] The obtained zirconium pyrophosphate composite ceramic material was detected by the method of Example 1, and the results were as follows: the room-temperature dielectric constant of the obtained zirconium pyrophosphate composite ceramic material was 8.1 (frequency: 10 GHz); the room-temperature dielectric loss was 1.5×10 -3 (frequency: 10 GHz); the room-temperature thermal conductivity was 1.7 W / (m·K); the relative density was 94.2%.

[0106] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A zirconium pyrophosphate composite ceramic material, characterized in that, It includes a main crystal phase and a second crystal phase. The main crystal phase is zirconium pyrophosphate, and the second crystal phase is alkali metal zirconium phosphate.

2. The zirconium pyrophosphate composite ceramic material according to claim 1, characterized in that, The alkali metal in the alkali metal zirconium phosphate is lithium, sodium or potassium.

3. The preparation method of the zirconium pyrophosphate composite ceramic material according to claim 1 or 2, characterized in that, It includes the following steps: Mix zirconium pyrophosphate powder and alkali metal fluoride powder, and grind them to obtain ceramic powder; Age, granulate and shape the ceramic powder in sequence to obtain a green body; Sinter the green body to obtain the zirconium pyrophosphate composite ceramic material.

4. The preparation method according to claim 3, wherein The mass of the alkali metal fluoride powder is greater than or equal to 1% of the mass of the zirconium pyrophosphate powder; The alkali metal fluoride powder is lithium fluoride powder, sodium fluoride powder or potassium fluoride powder; The purity of the alkali metal fluoride powder is greater than or equal to 99.0%, and the particle size is less than or equal to 0.1 mm.

5. The preparation method according to claim 3 or 4, characterized in that, The preparation method of the zirconium pyrophosphate powder includes the following steps: Heat the zirconium hydrogen phosphate powder to obtain the zirconium pyrophosphate powder; The purity of the zirconium hydrogen phosphate powder is greater than or equal to 99.0%, and the particle size is less than or equal to 10 μm; The heating temperature is 700 - 1000 °C, and the heat preservation time is 1 - 3 h; The heating is carried out under air atmosphere and normal pressure conditions.

6. The preparation method according to claim 3, characterized in that, The grinding method is wet grinding. The medium for wet grinding is water, the grinding balls for wet grinding are zirconia balls, the rotation speed for wet grinding is 300 - 450 rpm, and the time is 3 - 5 h.

7. The preparation method according to claim 3, characterized in that, The reagent for aging is an aqueous solution of polyvinyl alcohol. The concentration of the aqueous solution of polyvinyl alcohol is 4 wt%, and the mass ratio of the ceramic powder to the aqueous solution of polyvinyl alcohol is 20:1 - 2; The aging time is 18 - 30 h, and the aging is carried out under static and sealed conditions.

8. The preparation method according to claim 3, characterized in that, The shaping includes mechanical pressing and cold isostatic pressing in sequence. The pressure for mechanical pressing is 10 - 50 MPa, and the pressure holding time is 0.5 - 2 min; the pressure for cold isostatic pressing is 100 - 300 MPa, and the pressure holding time is 1 - 3 min.

9. The preparation method according to claim 3, characterized in that, The sintering temperature is 800 - 1000 °C, and the heating rate to the sintering temperature is 5 - 10 °C / min; the heat preservation time for sintering is 1 - 5 h; The sintering is carried out under air atmosphere and normal pressure conditions.

10. Application of the zirconium pyrophosphate composite ceramic material according to any one of claims 1 - 2 or the zirconium pyrophosphate composite ceramic material prepared by the preparation method according to any one of claims 3 - 9 in microwave mobile communication.

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