Low-temperature sintering microwave dielectric material and preparation method thereof

Abstract

The application relates to the field of electronic information functional ceramics and electronic devices, and discloses a low-temperature sintering microwave dielectric material and a preparation method thereof. 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6‑(1‑x)Ca 0.8 Sm 0.4 / 3 TiO3+ywt.%MO, the MO being a sintering aid, wherein 0.1<=x<=0.5 and 0.4<=y<=1; the microwave dielectric material prepared by the application has excellent microwave dielectric properties: the dielectric constant can reach 40-55, the Qxf value can reach 45000-60000 GHz, and the frequency temperature coefficient tauf can reach 0.8-4.9 ppm / degree Celsius.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic information functional ceramics and electronic devices, and particularly relates to a low-temperature sintering microwave dielectric material and a preparation method thereof. BACKGROUND

[0002] The microwave dielectric ceramic material refers to a ceramic material applied in a 300MHz-300GHz wave band as a dielectric material and completing one or more functions, which is widely applied to microwave components such as resonators, filters, capacitors and dielectric waveguide circuits in modern communication, and is an indispensable core material for different applications such as millimeter wave communication, electronic circuit packaging, dielectric resonant antenna, base station communication and miniaturized mobile communication.

[0003] The ceramic material with a medium dielectric constant and a high quality factor is mainly used for manufacturing high-end microwave components such as dielectric resonators, dielectric filters, GPS antennas and ring isolators, and the high quality factor and high dielectric constant enable the microwave components to have good electrical properties and realize the miniaturization of electronic components. With the continuous development of communication technology and the continuous enhancement of people's environmental protection awareness, the quality requirements of the electronic industry for electronic components are also continuously improved, and an ideal microwave dielectric ceramic material should have a suitable dielectric constant, low dielectric loss, high quality factor and a resonant frequency temperature coefficient close to zero.

[0004] At present, (Zr, Sn)TiO4, BaO-TiO2 and CaTiO3-NdAlO3 and other medium dielectric ceramic materials have been maturely researched and put into commercial production, but these systems still have some deficiencies: the (Zr, Sn)TiO4 ceramic is prone to produce oxygen vacancy defects due to a high sintering temperature, thereby increasing dielectric loss; the stoichiometric ratio and sintering range of the BaO-TiO2 ceramic are very narrow and difficult to control, and a second phase is easily produced to deteriorate dielectric properties; and the preparation of the CaTiO3-NdAlO3 ceramic mainly has defects of a high sintering temperature and unstable performance, so there is an urgent need for a microwave dielectric material with a low sintering temperature, a suitable dielectric constant, a high quality factor as much as possible and a resonant frequency temperature coefficient close to zero. SUMMARY

[0005] To solve the deficiencies mentioned in the background, the purpose of the present application is to provide a low-temperature sintering microwave dielectric material and a preparation method thereof, and the microwave dielectric ceramic material prepared at a sintering temperature of 1100-1250 DEG C obtains excellent microwave dielectric properties: the dielectric constant can reach 40-55, the Qxf value can reach 45000-60000 GHz, and the frequency temperature coefficient τf can reach 0.8-4.9 ppm / DEG C.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A low-temperature sintering microwave dielectric material, a composition expression of the microwave dielectric material is: xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3+ywt.%MO, MO is a sintering aid, wherein: 0.1≤x≤0.5, 0.4≤y≤1, a sintering temperature of the microwave dielectric material is 1100-1250℃.

[0008] Preferably, the sintering aid is Li2B4O7 and ZnO, a molar ratio of the Li2B4O7 and ZnO is 1:1.

[0009] Preferably, a preparation method of the sintering aid comprises the following steps: after lithium carbonate, boron oxide and zinc oxide powders are prepared according to a proportion, the powders are added into a ball mill tank, ball milling is carried out at a rotating speed of 150r / min for 2h, the ball milling slurry is dried and then passed through a 200-mesh screen to obtain a mixed powder raw material, then the mixed powder raw material is loaded into an alumina crucible, and the alumina crucible is heated at a temperature increasing rate of 4℃ / min to 800℃ and kept for 2h, and the sintering aid is prepared after cooling.

[0010] Preferably, a dielectric constant of the microwave dielectric material is 40-55, a Qxf value is 45000-60000GHz, and a frequency temperature coefficient τf is 0.8-4.9ppm / ℃.

[0011] Preferably, when x=0.1, a dielectric constant of the microwave dielectric material is 53.5, a Qxf value is 45300GHz, and a frequency temperature coefficient τf is 4.9ppm / ℃, when x=0.33, a dielectric constant of the microwave dielectric material is 48.0, a Qxf value is 52140GHz, and a frequency temperature coefficient τf is 2.6ppm / ℃, and when x=0.5, a dielectric constant of the microwave dielectric material is 40.3, a Qxf value is 59800GHz, and a frequency temperature coefficient τf is 0.8ppm / ℃.

[0012] A preparation method of a low-temperature sintering microwave dielectric material, comprising the following steps:

[0013] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate and samarium trioxide as raw materials, first, lithium carbonate, magnesium oxide, tin dioxide and titanium dioxide are weighed according to a composition expression of Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6, and then mixed uniformly to obtain a mixed material one; calcium carbonate and samarium trioxide are weighed according to a composition expression of Ca 0.8 Sm0.4 / 3 The composition expression of TiO3 is called calcium carbonate, samarium trioxide and titanium dioxide, and then the mixture is obtained.

[0014] S2, mixing: the mixture one and the mixture two are respectively subjected to ball milling and drying to obtain dry powder one and dry powder two;

[0015] S3, pre-burning: the dry powder one and the dry powder two are respectively placed in an alumina crucible, and then high-temperature calcination is carried out in a pre-burning furnace to obtain synthetic material one and synthetic material two;

[0016] S4, secondary batching: according to xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3 composition expression, according to the value of x, the synthetic material one and the synthetic material two are respectively taken, and then 0.4-1wt.% sintering aid is added to obtain a mixture;

[0017] S5, mixing and crushing: the mixture is mixed and crushed in a ball mill tank, and the ball milling medium is zirconium ball and deionized water to obtain a mixed slurry;

[0018] S6, slurry preparation and granulation: 2-5wt.% polyvinyl alcohol binder is added to the mixed slurry, and then spray granulation is carried out to obtain a granulated powder;

[0019] S7, forming and sintering: the granulated powder is pressed to obtain a green body, the green body is placed in a box-type electric furnace to heat and degas, and then sintered into porcelain in a muffle furnace to prepare a microwave dielectric material.

[0020] Preferably, the ball milling medium in step S2 is zirconium ball and ethanol, and the mass ratio of the mixture one, ethanol and zirconium ball is 1:3:10, and the mass ratio of the mixture two, ethanol and zirconium ball is 1:3:10.

[0021] Preferably, the pre-burning temperature in step S3 is 1000-1150℃, and the pre-burning time is 3-4h.

[0022] Preferably, the temperature for heating and degassing in step S7 is 550-600℃, the heating rate is 3-5℃ / min, and the holding time is 1-2h.

[0023] Preferably, the sintering temperature in step S7 is 1100-1250℃.

[0024] The beneficial effects of the present application are:

[0025] The present application utilizes lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate and samarium trioxide to prepare a microwave dielectric material with an expression of xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3, adopts (Li 2 / 3 Sn 1 / 3 ) 2+ ion substitution Mg 2+ Ion doping modification is carried out on the Li2Mg3TiO6 ceramic, the dielectric property of the microwave dielectric material is improved, and low-melting-point sintering aids Li2B4O7 and ZnO are added to reduce the sintering temperature of the microwave dielectric material, when (Li 2 / 3 Sn 1 / 3 ) 2+ When the doping amount is 0.02 mol%, the microwave dielectric ceramic material sintered at 1100-1250 ℃ obtains excellent microwave dielectric property: the dielectric constant can reach 40-55, the Qxf value can reach 45000-60000 GHz, and the frequency temperature coefficient τf can reach 0.8-4.9 ppm / ℃. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] The preparation method of a sintering aid in Example 1 comprises the following steps:

[0028] Lithium carbonate, boron oxide and zinc oxide powder are prepared according to the proportion of 50% Li2B4O7 and 50% ZnO (molar fraction), then added into a ball mill tank under a rotation speed of 150 r / min for 2 h, the ball-milled slurry is dried and then passed through a 200-mesh screen to obtain a mixed powder raw material, then loaded into an alumina crucible, and then heated to 800 ℃ at a rate of 4 ℃ / min and kept for 2 h, and then cooled to prepare the sintering aid.

[0029] The preparation method of a low-temperature sintering microwave dielectric material in Example 2 comprises the following steps:

[0030] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate and samarium trioxide as raw materials, first according to Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3) 0.02 The composition expression of Li2[Mg 0.8 Sm 0.4 / 3 The composition expression of Li2[Mg

[0031] S2, mixing: the mixed material one and the mixed material two are respectively subjected to ball milling and crushing treatment and dried to obtain dry powder material one and dry powder material two, the ball milling medium is zirconium ball and ethanol, the mass ratio of the mixed material one, ethanol and zirconium ball is 1:3:10, the mass ratio of the mixed material two, ethanol and zirconium ball is 1:3:10;

[0032] S3, pre-burning: the dry powder material one and the dry powder material two are respectively placed in an alumina crucible, and are calcined at 1100℃ for 3h in a pre-burning furnace to obtain synthetic material one and synthetic material two;

[0033] S4, secondary batching: according to the composition expression of Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3, when x is 0.1, the synthetic material one and the synthetic material two are respectively weighed, then 1wt.% of the sintering aid prepared in Example 1 is added to obtain a mixed material;

[0034] S5, mixing and crushing: the mixed material is mixed and crushed in a ball milling tank, the ball milling medium is zirconium ball and deionized water, the mass ratio of zirconium ball, mixed material and deionized water is 10:1:3, the ball milling speed is 200r / min, the ball milling time is 24h, and a mixed slurry is obtained;

[0035] S6, slurry preparation and granulation: 4wt.% of polyvinyl alcohol binder based on the weight of the mixed slurry is added to the mixed slurry, and then spray granulation is performed to obtain a granulated powder;

[0036] S7, forming and sintering: the granulated powder is subjected to compression molding to obtain a green body, the green body is placed in a box-type electric furnace and heated to 600℃ at a rate of 3℃ / min, and then heat treated for 1h to remove glue, and then placed in a muffle furnace and heated to 1100℃ at a rate of 5℃ / min to sinter into porcelain, thereby preparing a microwave dielectric material.

[0037] Example 3, a method for preparing a low-temperature sintering microwave dielectric material, comprising the following steps:

[0038] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate and samarium trioxide as raw materials, first according to the composition expression of Li2[Mg 0.98(Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3of the composition formula, x is 0.33, respectively, then add 1wt.% of the sintering aid prepared in Example 1 to obtain a mixture;

[0039] S2, mixing: the mixture one and the mixture two are respectively subjected to ball milling and crushing treatment and dried to obtain dry powder one and dry powder two, the ball milling medium is zirconium ball and ethanol, the mass ratio of the mixture one, ethanol and zirconium ball is 1:3:10, the mass ratio of the mixture two, ethanol and zirconium ball is 1:3:10;

[0040] S3, pre-burning: the dry powder one and the dry powder two are respectively placed in an alumina crucible, calcined at 1100℃ for 3h in a pre-burning furnace to obtain synthesis one and synthesis two;

[0041] S4, secondary batching: according to the composition formula xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3of the composition formula, x is 0.33, respectively, then add 1wt.% of the sintering aid prepared in Example 1 to obtain a mixture;

[0042] S5, mixing and crushing: the mixture is mixed and crushed in a ball milling tank, the ball milling medium is zirconium ball and deionized water, the mass ratio of zirconium ball, mixture and deionized water is 10:1:3, the ball milling speed is 200r / min, the ball milling time is 24h, to obtain a mixed slurry;

[0043] S6, slurry preparation and granulation: 4wt.% of polyvinyl alcohol binder is added to the mixed slurry, then spray granulation is carried out to obtain granulated powder;

[0044] S7, forming and sintering: the granulated powder is pressed to form a green body, the green body is placed in a box-type electric furnace and heated to 600℃ at a rate of 3℃ / min, and then the temperature is kept for 1h to remove glue, then the green body is placed in a muffle furnace and heated to 1100℃ at a rate of 5℃ / min to sinter into porcelain, to prepare a microwave dielectric material.

[0045] Example 4, a method for preparing a low-temperature sintering microwave dielectric material, comprising the following steps:

[0046] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate, and samarium trioxide as raw materials, first, according to the composition expression of Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6, take lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide and mix uniformly to obtain mixed material one; according to the composition expression of Ca 0.8 Sm 0.4 / 3 TiO3, take calcium carbonate, samarium trioxide, and titanium dioxide and mix uniformly to obtain mixed material two;

[0047] S2, mixing: after the mixed material one and the mixed material two are respectively subjected to ball milling and crushing treatment and drying, dry powder one and dry powder two are obtained, the ball milling medium is zirconium ball and ethanol, the mass ratio of the mixed material one, ethanol and zirconium ball is 1:3:10, the mass ratio of the mixed material two, ethanol and zirconium ball is 1:3:10;

[0048] S3, pre-burning: the dry powder one and the dry powder two are respectively placed in an alumina crucible, and after calcination at 1100℃ for 3h in a pre-burning furnace, synthetic material one and synthetic material two are obtained;

[0049] S4, secondary batching: according to the composition expression of xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3, when x is 0.5, the synthetic material one and the synthetic material two are respectively taken, then 1wt.% of the sintering aid prepared in example 1 is added to obtain a mixed material;

[0050] S5, mixing and crushing: the mixed material is mixed and crushed in a ball milling tank, the ball milling medium is zirconium ball and deionized water, the mass ratio of zirconium ball, mixed material and deionized water is 10:1:3, the ball milling speed is 200r / min, the ball milling time is 24h, and a mixed slurry is obtained;

[0051] S6, slurry preparation and granulation: 4wt.% of polyvinyl alcohol binder based on the weight of the mixed slurry is added to the mixed slurry, then spray granulation is carried out, and a granulated powder is obtained;

[0052] S7, shaping and sintering: the granulated powder is pressed to obtain a green body, the green body is placed in a box-type electric furnace and heated to 600℃ at a rate of 3℃ / min for 1h to remove glue, then placed in a muffle furnace and heated to 1100℃ at a rate of 5℃ / min to sinter into porcelain, and a microwave dielectric material is prepared.

[0053] Embodiment 5 A method for preparing a low-temperature sintering microwave dielectric material, comprising the following steps:

[0054] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate, and samarium trioxide as raw materials, first, according to the composition expression of Li2[MgSn]3TiO6, lithium carbonate, magnesium oxide, tin dioxide, and titanium dioxide are weighed and uniformly mixed to obtain mixed material one; according to the composition expression of CaSmTiO3, calcium carbonate, samarium trioxide, titanium dioxide, magnesium oxide, and niobium pentoxide are weighed and uniformly mixed to obtain mixed material two; 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material; 0.8 Sm 0.4 / 3 TiO3;

[0055] S2, mixing: after the mixed material one and the mixed material two are respectively subjected to ball milling and crushing treatment and dried, dry powder one and dry powder two are obtained, the ball milling medium is zirconium balls and ethanol, the mass ratio of the mixed material one, ethanol, and zirconium balls is 1:3:10, and the mass ratio of the mixed material two, ethanol, and zirconium balls is 1:3:10;

[0056] S3, pre-sintering: the dry powder one and the dry powder two are respectively placed in an alumina crucible, calcined at 1100°C for 3h in a pre-sintering furnace to obtain synthetic material one and synthetic material two;

[0057] S4, secondary batching: according to the composition expression of xLi2[MgSn]3TiO6-(1-x)CaSmTiO3, x is 0.33, the synthetic material one and the synthetic material two are respectively weighed, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material; 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3;

[0058] S5, mixing and crushing: the mixed material is mixed and crushed in a ball milling tank, the ball milling medium is zirconium balls and deionized water, the mass ratio of the zirconium balls, the mixed material, and the deionized water is 10:1:3, the ball milling speed is 200r / min, the ball milling time is 24h, and a mixed slurry is obtained;

[0059] S6, slurry preparation and granulation: 4wt.% of polyvinyl alcohol binder based on the weight of the mixed slurry is added to the mixed slurry, and then spray granulation is performed to obtain a granulated powder;

[0060] S7, molding sintering: the granulated powder is pressed to obtain a green body, the green body is placed in a box-type electric furnace to be heated to 600℃ at a rate of 3℃ / min and kept for 1h to remove glue, and then placed in a muffle furnace to be heated to 1200℃ at a rate of 5℃ / min to sinter into porcelain, so that a microwave dielectric material is prepared.

[0061] Embodiment 6: A preparation method of a low-temperature sintering microwave dielectric material, comprising the following steps:

[0062] S1, batching: taking lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate and samarium sesquioxide as raw materials, first, according to the composition expression of Li2[MgSn]3TiO6, lithium carbonate, magnesium oxide, tin dioxide and titanium dioxide are weighed and uniformly mixed to obtain a mixed material one; according to the composition expression of CaSmTiO3, calcium carbonate, samarium sesquioxide and titanium dioxide are weighed and uniformly mixed to obtain a mixed material two; 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material; 0.8 Sm 0.4 / 3 TiO3, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material;

[0063] S2, mixing: the mixed material one and the mixed material two are respectively subjected to ball milling and pulverization treatment and then dried to obtain dry powder one and dry powder two, the ball milling medium is zirconium balls and ethanol, the mass ratio of the mixed material one, ethanol and zirconium balls is 1:3:10, and the mass ratio of the mixed material two, ethanol and zirconium balls is 1:3:10;

[0064] S3, pre-sintering: the dry powder one and the dry powder two are respectively placed in an alumina crucible and calcined at 1100℃ for 3h in a pre-sintering furnace to obtain a synthetic material one and a synthetic material two;

[0065] S4, secondary batching: according to the composition expression of xLi2[MgSn]3TiO6-(1-x)CaSmTiO3, x is 0.33, the synthetic material one and the synthetic material two are respectively weighed, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material; 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3, and then 1wt.% of the sintering aid prepared in Embodiment 1 is added to obtain a mixed material;

[0066] S5, mixing and pulverization: the mixed material is mixed and pulverized in a ball milling tank, the ball milling medium is zirconium balls and deionized water, the mass ratio of zirconium balls, the mixed material and deionized water is 10:1:3, the ball milling speed is 200r / min, and the ball milling time is 24h to obtain a mixed slurry;

[0067] S6. Pulping and granulation: Add 4 wt% polyvinyl alcohol binder to the mixed slurry, and then perform spray granulation to obtain granulated powder.

[0068] S7. Molding and Sintering: The granulated powder is pressed into a green body. The green body is placed in a box furnace and heated to 600°C at 3°C / min and held for 1 hour to remove the binder. Then it is placed in a muffle furnace and sintered to 1250°C at 5°C / min to obtain microwave dielectric material.

[0069] Example 7: A method for preparing a low-temperature sintered microwave dielectric material, comprising the following steps:

[0070] S1. Ingredients: Lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate, and samarium trioxide are used as raw materials. First, according to Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 The composition formula of 3TiO6 is as follows: Lithium carbonate, magnesium oxide, tin dioxide, and titanium dioxide are weighed and mixed evenly to obtain mixture one; according to Ca 0.8 Sm 0.4 / 3 The composition formula of TiO3 is as follows: calcium carbonate, samarium trioxide, and titanium dioxide are weighed and mixed evenly to obtain mixture two;

[0071] S2. Mixing: Mixture 1 and Mixture 2 are ball-milled and pulverized separately and then dried to obtain dry powder 1 and dry powder 2. The ball milling media are zirconium balls and ethanol. The mass ratio of mixture 1, ethanol and zirconium balls is 1:3:10, and the mass ratio of mixture 2, ethanol and zirconium balls is 1:3:10.

[0072] S3. Pre-calcination: Dry powder one and dry powder two are placed in alumina crucibles respectively, and calcined in a pre-calcination furnace at 1100℃ for 3 hours to obtain synthetic material one and synthetic material two.

[0073] S4. Secondary batching: According to xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 The compositional expression of TiO3 is given. When x is 0.33, the first and second synthetic materials are weighed separately, and then 0.5 wt.% of the sintering aid prepared in Example 1 is added to obtain the mixture.

[0074] S5, mixing and crushing: the mixture is mixed and crushed in a ball mill tank, the ball mill medium is zirconium ball and deionized water, the mass ratio of zirconium ball, mixture and deionized water is 10:1:3, the ball mill rotation speed is 200 r / min, the ball mill time is 24 h, and the mixed slurry is obtained;

[0075] S6, slurry preparation and granulation: 4wt% of polyvinyl alcohol binder in the mixed slurry is added, and then spray granulation is carried out, and the granulation powder is obtained;

[0076] S7, forming and sintering: the granulation powder is pressed to obtain a green body, the green body is placed in a box-type electric furnace, heated to 600℃ at a rate of 3℃ / min, and then the glue is removed for 1h, and then placed in a muffle furnace, heated to 1125℃ at a rate of 5℃ / min, and sintered into a ceramic, to prepare a microwave dielectric material.

[0077] Performance detection

[0078] The microwave dielectric material prepared in examples 2-7 is subjected to performance detection: the dielectric constant (εr), quality factor (Qxf) and resonance frequency temperature coefficient (τf) of the sample are tested by using a microwave network analyzer; the resonance frequency f(T) at T temperature is measured, and the resonance frequency temperature coefficient is calculated by the formula: τf=(f T2 -f T1 ) / [f T2 ×(T2-T1)], wherein T2 is 85℃, and T1 is 25℃, and the data results are shown in Table 1.

[0079] Table 1 performance detection results of samples

[0080]

[0081] From the data in Table 1, it can be seen that the microwave dielectric ceramic material prepared in examples 2-7 at a sintering temperature of 1100-1250℃ obtains excellent microwave dielectric properties: the dielectric constant can reach 40-55, the Qxf value can reach 45000-60000 GHz, and the frequency temperature coefficient τf can reach 0.8-4.9 ppm / ℃.

[0082] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0083] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A low temperature sintered microwave dielectric material, characterized in that, The composition expression of the microwave dielectric material is: xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3+ywt.%MO, MO is a sintering aid, wherein: 0.1≤x≤0.5, 0.4≤y≤1, the sintering temperature of the microwave dielectric material is 1100~1250℃; The sintering aid is Li2B4O7 and ZnO, and the molar ratio of the Li2B4O7 and ZnO is 1:1; the preparation method of the sintering aid comprises the following steps: lithium carbonate, boron oxide and zinc oxide powder are prepared according to the proportion, then added into a ball mill tank, ball milled at a speed of 150 r / min for 2 h, the ball milled slurry is dried and then passed through a 200 mesh screen to obtain a mixed powder raw material, then loaded into an alumina crucible, heated to 800 DEG C at a rate of 4 DEG C / min and kept for 2 h, and the sintering aid is prepared after cooling.

2. The low temperature sintered microwave dielectric material of claim 1, wherein, The microwave dielectric material has a dielectric constant of 40-55, a Qxf value of 45000-60000 GHz, and a frequency temperature coefficient τf of 0.8-4.9 ppm / ℃.

3. The low temperature sintered microwave dielectric material of claim 1, wherein, When x=0.1, the microwave dielectric material has a dielectric constant of 53.5, a Qxf value of 45300 GHz, and a frequency temperature coefficient τf of 4.9 ppm / ℃; when x=0.33, the microwave dielectric material has a dielectric constant of 48.0, a Qxf value of 52140 GHz, and a frequency temperature coefficient τf of 2.6 ppm / ℃; when x=0.5, the microwave dielectric material has a dielectric constant of 40.3, a Qxf value of 59800 GHz, and a frequency temperature coefficient τf of 0.8 ppm / ℃.

4. A method for producing a low-temperature sintered microwave dielectric material according to any one of claims 1 to 3, characterized by, The method comprises the following steps: S1, batching: with lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide, calcium carbonate, samarium trioxide as raw materials, firstly, according to Li2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6 composition expression, take lithium carbonate, magnesium oxide, tin dioxide, titanium dioxide and mix uniformly to obtain mixed material one; according to Ca 0.8 Sm 0.4 / 3 TiO3 composition expression, take calcium carbonate, samarium trioxide, titanium dioxide and mix uniformly to obtain mixed material two; S2, mixing: the mixed material one and the mixed material two are respectively subjected to ball milling, powder crushing treatment and drying to obtain dry powder one and dry powder two; S3, pre-sintering: the dry powder one and the dry powder two are respectively placed in an alumina crucible, and high-temperature calcination is carried out in a pre-sintering furnace to obtain synthesis material one and synthesis material two; S4, secondary batching: according to xLi2[Mg 0.98 (Li 2 / 3 Sn 1 / 3 ) 0.02 ]3TiO6-(1-x)Ca 0.8 Sm 0.4 / 3 TiO3, according to the value of x, the synthetic material 1 and the synthetic material 2 are respectively taken, and then 0.4-1wt.% sintering aids are added to obtain a mixture; S5, mixing and crushing: the mixed material is mixed and crushed in a ball mill tank, and the ball milling medium is zirconium ball and deionized water to obtain mixed slurry; S6, slurry preparation and granulation: 2-5wt% of polyvinyl alcohol binder based on the weight of the mixed slurry is added to the mixed slurry, and then spray granulation is carried out to obtain granulated powder; S7, forming and sintering: the granulated powder is pressed to obtain a green body, the green body is placed in a box-type electric furnace to heat and degas, and then sintered into porcelain in a muffle furnace to prepare the microwave dielectric material.

5. The method of claim 4, wherein the low temperature sintered microwave dielectric material is represented by the formula: (Ba1-xSrx) (Ti1-yZry) O3, wherein 0 < x < 1 and 0 < y < 1. In the step S2, the ball milling medium is zirconium ball and ethanol, and the mass ratio of the mixed material one, ethanol and zirconium ball is 1:3:10, and the mass ratio of the mixed material two, ethanol and zirconium ball is 1:3:

10.

6. The method of claim 4, wherein the low temperature sintered microwave dielectric material is represented by the formula: (Ba1-xSrx) (Ti1-yZry) O3, wherein 0 < x < 1 and 0 < y < 1. In the step S3, the pre-sintering temperature is 1000-1150 DEG C, and the pre-sintering time is 3-4 h.

7. The method for preparing low-temperature sintered microwave dielectric material according to claim 4, characterized in that, In the step S7, the temperature for heating and degassing is 550-600 DEG C, the heating rate is 3-5 DEG C / min, and the holding time is 1-2 h.

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