阅读说明：本技术 一种锂基微波介质陶瓷材料、其制备方法和锂基微波介质陶瓷 (Lithium-based microwave dielectric ceramic material, preparation method thereof and lithium-based microwave dielectric ceramic ) 是由 马丹丹 周世平 周纪平 温俊磊 李武 裴广斌 于 2020-12-17 设计创作，主要内容包括：本发明提供了一种锂基微波介质陶瓷材料,原料包括：式(I)所示的主粉体和辅助粉体；所述辅助粉体包括占主粉体0.5～1.5wt％的玻璃粉和占主粉体5～10wt％金红石型TiO-2微粉；Li-2(Zn-((1-x))Cu-x)(Ti-((1-y))(Mg-(1/3)Nb-(2/3))-y)-3O-8,式(I)。本发明特定的玻璃粉料降低体系的烧结温度,引入Mg～(2+)、Nb～(5+)取代Ti～(4+)改善频率温度系数,引入TiO-2可以提高Li-2CO-3-ZnO-TiO-2体系的烧结致密性,可以调节τ-f值。Cu～(2+)取代及特定的玻璃粉料成功使得Li-2CO-3-ZnO-TiO-2体系在850～890℃烧结完善且具有优异介电性能,从而使得该材料能够与Ag电极共烧。(The invention provides a lithium-based microwave dielectric ceramic material, which comprises the following raw materials: a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and rutile type TiO accounting for 5-10 wt% of the main powder 2 Micro-powder; li 2 (Zn (1‑x) Cu x )(Ti (1‑y) (Mg 1/3 Nb 2/3 ) y ) 3 O 8 Formula (I). The specific glass powder of the invention reduces the sintering temperature of the system and introduces Mg 2+ 、Nb 5+ Substituted Ti 4+ Improving the frequency temperature coefficient and introducing TiO 2 Can increase Li 2 CO 3 ‑ZnO‑TiO 2 The sintering compactness of the system can be adjusted to be tau f The value is obtained. Cu 2+ The substitution and specification of glass frit successfully enabled Li 2 CO 3 ‑ZnO‑TiO 2 The system is sintered at 850-890 ℃ and has excellent dielectric property, so that the material can be co-sintered with an Ag electrode.)

1. A lithium-based microwave dielectric ceramic material is characterized in that the raw materials comprise:

a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and rutile type TiO accounting for 5-10 wt% of the main powder₂Micro-powder;

Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈formula (I);

wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2.

2. The lithium-based microwave dielectric ceramic material as claimed in claim 1, wherein the glass frit is Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃A glass system;

the glass powder D50 is 2-4 mu m;

the rutile type TiO₂The particle diameter D50 of the fine powder is 0.5 to 1.0 μm.

3. The lithium-based microwave dielectric ceramic material as claimed in claim 2, wherein the glass powder is prepared by performing wet ball milling, drying, smelting and crushing on the following raw materials in parts by weight:

4. the lithium-based microwave dielectric ceramic material of claim 3 wherein the raw material of the glass frit further comprises a pretreatment comprising: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; na (Na)₂CO₃、K₂CO₃And B₂O₃Drying the mixture in an oven at 100-120 ℃ for 1-2 h respectively;

the smelting temperature is 1200-1350 ℃.

5. The lithium-based microwave dielectric ceramic material as claimed in claim 1, wherein the main powder represented by formula (I) is Li₂ZnTi₃O₈、Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈、Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈、Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈、Li₂(Zn_0.975Cu_0.025)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Or Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈One or more of them.

6. The preparation method of the lithium-based microwave dielectric ceramic material as claimed in any one of claims 1 to 5, characterized by comprising the following steps:

a main powder body, glass powder and rutile type TiO shown in formula (I)₂Mixing the micro powder, ball milling by a wet method, drying, mixing with a binder, granulating, pressing and sintering to obtain the nano-composite material.

7. The preparation method according to claim 6, wherein the preparation method of the main powder represented by the formula (I) specifically comprises:

Li₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Mixing according to a metering ratio, grinding by a wet method, drying, presintering and crushing to obtain the product.

8. The preparation method according to claim 7, wherein the preparation method of the main powder represented by the formula (I) further comprises pretreatment of ZnO and MgO, and the pretreatment specifically comprises: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; preserving the temperature of MgO at 700-800 ℃ for 4-5 h;

the particle size of the MgO is 40-80 nm;

the pre-sintering temperature is 800-900 ℃; the time is 2-6 h;

and crushing to obtain a main powder represented by the formula (I) with D50 being 1-3 μm.

9. The preparation method of claim 6, wherein the wet ball milling time is 3-4 h; the drying temperature is 120-140 ℃; the binder is polyvinyl alcohol; the pressing pressure is 140-150 Mpa; the sintering temperature is 850-890 ℃; the sintering time is 0.5-1 h.

10. A lithium-based microwave dielectric ceramic prepared from the ceramic material according to any one of claims 1 to 5 or the ceramic material prepared by the preparation method according to any one of claims 6 to 9.

11. A microwave device prepared from the ceramic material of any one of claims 1 to 5 or the ceramic material prepared by the preparation method of any one of claims 6 to 9.

Technical Field

The invention relates to the technical field of materials, in particular to a lithium-based microwave dielectric ceramic material with a dielectric constant in low-temperature sintering, a preparation method thereof and a lithium-based microwave dielectric ceramic.

Background

With the development of electronic information technology towards high frequency and digitization, the requirements for integration and modularization of components and circuits are more and more urgent, and Low Temperature Co-fired ceramic LTCC (Low Temperature Co-fired ceramic) has become one of the hot spots for the modularization research of electronic devices due to its excellent electrical, mechanical, process characteristics and high reliability. With the progress of science and technology, the LTCC technology puts higher requirements on microwave dielectric ceramic materials: (1) excellent microwave dielectric property, proper dielectric constant, low loss and near-zero temperature coefficient of resonant frequency; (2) the sintering temperature is lower than 900 ℃, so that the sintering and the sintering of the Ag electrode material are realized; (3) the electrode material does not generate chemical reaction, the interface combination of the electrode material and the electrode material is firm, and the sintering shrinkage matching performance is good.

Most of the microwave dielectric ceramics such as MgTiO at present₃、Nd(Zn_0.5Ti_0.5)O₃、Ba(Mg_1/3Ta_2/3)O₃And the like have excellent performance, but the sintering temperature is too high (not less than 1300 ℃) to be applied to the LTCC technology. Therefore, more and more researches are put on exploring a material system which has low sintering temperature and excellent performance and can realize co-firing compatibility with Ag electrodes. Li of spinel structure₂ZnTi₃O₈Is a material with low inherent sintering temperature (1080 ℃) and excellent dielectric propertyMicrowave dielectric materials of properties, in addition Li₂ZnTi₃O₈The ceramic has the advantages of low cost, good economy, easy realization of industrialization and the like, thereby having wide application prospect and attracting the wide attention of people. Researchers at home and abroad are mainly aimed at reducing Li₂ZnTi₃O₈Some studies have been made on the sintering temperature and the improvement of the temperature coefficient of the resonance frequency. Wherein Lihua Kai, Lvwen, Leiwen, etc. are in "H₃BO₃Doping with Li₂ZnTi₃O₈Microwave dielectric properties of ceramics "in the text (electronic components and materials, 2012,31(2):5-7.) Li was investigated₂ZnTi₃O₈Doping with 2 wt% H₃BO₃The porcelain material system has better dielectric property, epsilon, after being sintered at 950 ℃ for 4 hours_r＝25.99、Q×f＝54926GHz、τ_f＝-12.17×10^-6ppm/DEG C, but sintering temperature>The temperature is 900 ℃ and the heat preservation time is as long as 4 hours, so that the silver flying phenomenon is easy to occur; and a combustion assistant H₃BO₃Adverse effects can occur when preparing cast green tapes; ren H S, Hao L, Peng H Y et al in "Investigation on low-temperature configurable behavor and configurable dielectric properties of BLMT glass-Li₂ZnTi₃O₈composition ceramics "in the Journal of the European Ceramic Society,2018,38(10):3498-₂O₃-La₂O₃-MgO-TiO₂Glass pair Li₂ZnTi₃O₈Influence of ceramic sintering characteristics and dielectric properties, doping with 20 wt% B₂O₃-La₂O₃-MgO-TiO₂The sintering dielectric property is better when the temperature is kept at 900 ℃ for 2h_r＝22.7、Q×f＝19900GHz、τ_f＝0.28×10^-6ppm/DEG C, and glass addition levels up to 20 wt% were fired to lower the sintering temperature, resulting in Li₂ZnTi₃O₈System epsilon_rAnd the Qxf is low, the comprehensive performance is poor, and the application of the LTCC technology has certain limitation.

Invention patent "Li₂ZnTi₃O₈Microwave dielectric material and low-temperature sintering method' CN101913859A discloses an additive sintered at 900 DEG CLi with addition of low-melting substances₂ZnTi₃O₈Ceramic material (low melting point substance is H)₃BO₃、BaCu(B₂O₅)、V₂O₅And Bi₂O₃One of them). The material has a high temperature coefficient of resonance frequency (-47.2 to-20.7 ppm/DEG C), and the additive V₂O₅Has adverse effects in the production of cast green tapes. The invention discloses a low-temperature sintered lithium-based zinc-titanium microwave dielectric ceramic and a preparation method thereof, CN102617127A discloses that a sintering aid sintered at the temperature lower than 900 ℃ is H₃BO₃Or ZBS (60 wt% -ZnO, 30 wt% -B)₂O₃、10wt％-SiO₂) Li of (2)₂ZnTi₃O₈The ceramic material is added with a sintering aid, so that the dielectric property of a material system is deteriorated. The invention discloses a low-temperature co-fired microwave dielectric ceramic material and a preparation method thereof, CN102381874B discloses Li sintered at about 875 DEG C₂ZnTi₃O₈A ceramic material, wherein the low-melting substance is Li₂O-ZnO-B₂O₃Or Li₂O-B₂O₃-SiO₂The sintering heat preservation time of the glass in the material is 4 hours, the silver electrode is easy to ablate and erode after the heat preservation time is long, the Q x f integral of the material sintered at about 875 ℃ is slightly lower, the addition amount of different auxiliary components is different, the prepared material has poor comprehensive performance, the Q x f value and the tau_fCannot be considered well, such as: li₂ZnTi₃O₈Adding LBS 1 wt% and TiO 5 wt%₂Keeping the temperature at 875 ℃ for 4h for sintering, epsilon_r＝26.0、Q×f＝24079GHz、τ_f＝1.6×10^-6ppm/DEG C, again with Li addition₂O-B₂O₃-SiO₂Glass deteriorates Li₂ZnTi₃O₈The dielectric properties of the system.

In conclusion, it is necessary to develop a lithium-based microwave dielectric ceramic material with medium dielectric constant in low-temperature sintering and a preparation method thereof, which can overcome the defects of the existing lithium-based microwave dielectric material, such as too high sintering temperature, too long heat preservation time, difficulty in matching and co-firing with a silver electrode, adverse effect of an additive on dielectric property, and the like.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a low-temperature sintered medium-dielectric-constant lithium-based microwave dielectric ceramic material, which has the advantages of low sintering temperature, short heat preservation time and good dielectric property.

The invention provides a lithium-based microwave dielectric ceramic material, which comprises the following raw materials:

a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and rutile type TiO accounting for 5-10 wt% of the main powder₂Micro-powder;

Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈formula (I);

wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2.

Preferably, the glass powder is Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃A glass system;

the glass powder D50 is 2-4 mu m;

the rutile type TiO₂The particle size D50 of the micro powder is 0.5-1.0 μm;

preferably, the glass powder is prepared by performing wet ball milling, drying, smelting and crushing on the following raw materials in parts by weight:

preferably, the raw material of the glass frit further comprises a pretreatment comprising: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; na (Na)₂CO₃、K₂CO₃And B₂O₃Drying the mixture in an oven at 100-120 ℃ for 1-2 h respectively;

the smelting temperature is 1200-1350 ℃.

Preferably, the main powder represented by the formula (I) is Li₂ZnTi₃O₈、Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈、Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈、Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈、Li₂(Zn_0.975Cu_0.025)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Or Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_{1/ 3}Nb_2/3)_0.2)₃O₈One or more of them.

The invention provides a preparation method of a lithium-based microwave dielectric ceramic material in any one of the technical schemes, which comprises the following steps:

a main powder body, glass powder and rutile type TiO shown in formula (I)₂Mixing the micro powder, ball milling by a wet method, drying, mixing with a binder, granulating, pressing and sintering to obtain the nano-composite material.

Preferably, the preparation method of the main powder shown in the formula (I) specifically comprises the following steps:

Li₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Mixing according to a metering ratio, grinding by a wet method, drying, presintering and crushing to obtain the product.

Preferably, the preparation method of the main powder shown in the formula (I) further comprises pretreatment of ZnO and MgO, wherein the pretreatment specifically comprises: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; preserving the temperature of MgO at 700-800 ℃ for 4-5 h;

the particle size of the MgO is 40-80 nm;

the pre-sintering temperature is 800-900 ℃; the time is 2-6 h;

and crushing to obtain a main powder represented by the formula (I) with D50 being 1-3 μm.

Preferably, the wet ball milling time is 3-4 h; the drying temperature is 120-140 ℃; the binder is polyvinyl alcohol; the pressing pressure is 140-150 Mpa; the sintering temperature is 850-890 ℃; the sintering time is 0.5-1 h.

The invention provides lithium-based microwave dielectric ceramic which is prepared from the ceramic material or the ceramic material prepared by the preparation method.

The invention provides a microwave device, which is prepared from the ceramic material or the ceramic material prepared by the preparation method.

Compared with the prior art, the invention provides a lithium-based microwave dielectric ceramic material which comprises the following raw materials: a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and rutile type TiO accounting for 5-10 wt% of the main powder₂Micro-powder; li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Formula (I); wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2. The invention is in Li₂CO₃-ZnO-TiO₂By Cu on a system basis²⁺Substituted Zn²⁺To reduce Li₂CO₃-ZnO-TiO₂Presintering temperature and sintering temperature, introducing the glass powder material of the invention to reduce the sintering temperature of the system, introducing Mg²⁺、Nb⁵⁺Substituted Ti⁴⁺Improving the frequency temperature coefficient and introducing TiO₂On the one hand, Li can be increased₂CO₃-ZnO-TiO₂The sintering compactness of the system can be adjusted on the other hand_fThe value is obtained. Cu²⁺The substitution and specification of glass frit successfully enabled Li₂CO₃-ZnO-TiO₂The system can be sintered to be compact and obtain excellent dielectric property after being sintered for 1 hour at 850-890 ℃, so that the material can be co-sintered with an Ag electrode. The lithium-based microwave dielectric ceramic with the dielectric constant in low-temperature sintering has simple chemical composition and preparation process, and can be widely used for chip resonators, antennas, filters and the likeThe microwave device is an ideal low-temperature co-fired ceramic material for manufacturing.

Drawings

FIG. 1 is an XRD (X-ray diffraction pattern) of example 1 sintered at 890 ℃;

FIG. 2 is an XRD (X-ray diffraction pattern) of example 7 sintered at 875 ℃;

FIG. 3 is an SEM (scanning Electron micrograph) of example 1 sintered at 890 ℃;

FIG. 4 is an SEM (scanning Electron microscopy) image of example 7 sintered at 875 ℃.

Detailed Description

The invention provides a lithium-based microwave dielectric ceramic material with a dielectric constant in low-temperature sintering, a preparation method thereof and a lithium-based microwave dielectric ceramic. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention provides a lithium-based microwave dielectric ceramic material, which comprises the following raw materials:

a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and rutile type TiO accounting for 5-10 wt% of the main powder₂Micro-powder;

Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈formula (I);

wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2.

The invention provides a lithium-based microwave dielectric ceramic material which comprises the following raw materials: a main powder represented by the formula (I).

Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Formula (I);

wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2.

The main powder represented by the formula (I) in the present invention is preferably Li₂ZnTi₃O₈、Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈、Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈、Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈、Li₂(Zn_0.975Cu_0.025)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)Ti₃O₈、Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Or Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈One or more of them.

The preparation method of the main powder shown in the formula (I) is preferably as follows:

Li₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Mixing according to a metering ratio, grinding by a wet method, drying, presintering and crushing to obtain the product.

Li according to the invention₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅The purity is more than or equal to 99 percent, and the source of the product is not limited by the invention and can be sold in the market.

Firstly, pretreating raw materials, specifically pretreating ZnO and MgO.

The pretreatment specifically comprises the following steps: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; preferably presintering at 650-700 ℃ and preserving heat for 4-4.5 h; more preferably presintering at 700 ℃ and preserving heat for 4 hours;

preserving the temperature of MgO at 700-800 ℃ for 4-5 h; preferably, the temperature is kept at 750-800 ℃ for 4-4.5 h; more preferably, the temperature is kept for 4 hours at 800 ℃;

the particle size of the MgO is 40-80 nm.

Then to Li₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Mixing according to the metering ratio, and carrying out wet ball milling. The wet ball milling is carried out by taking water as grinding liquid, the ball-material ratio of the ball milling is 3:1, and the ball milling parameter is 300rpm/4 h.

And drying and presintering after wet grinding.

And drying the slurry obtained by ball milling, sieving by a 80-mesh sieve, and pressing into blocks. The drying temperature is 120 ℃ and the drying time is 4 h.

Then, pre-burning to prepare a pre-burning block.

The pre-sintering temperature is preferably 800-900 ℃; the time is preferably 2-6 h; more preferably 2-5 h; most preferably 2-4 h.

And crushing after pre-burning to obtain the product. The above-mentioned briquette was pulverized and ball-milled to obtain a main powder having a D50 of 1.15 μm.

The invention provides a low-temperature sintering medium dielectric constant lithium-based microwave dielectric ceramic material. The auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder; preferably, the glass powder accounts for 0.6-1.5 wt% of the main powder.

The glass powder is Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃A glass system; the glass powder D50 is 2-4 mu m;

according to the invention, the glass powder is prepared by carrying out wet ball milling, drying, smelting and crushing on the following raw materials in parts by weight:

in a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃2.5 parts; al (Al)₂O₃4.3 parts of a mixture; b is₂O₃54.6 parts; 1.8 parts of ZnO; SiO 2₂32.7 parts of a mixture; na (Na)₂CO₃1.2 parts; k₂CO₃0.6 part; BaCO₃1.5 parts; la₂O₃0.8 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃2.5 parts; al (Al)₂O₃4.3 parts of a mixture; b is₂O₃52.2 parts of; 1.8 parts of ZnO; SiO 2₂33.6 parts; na (Na)₂CO₃1.5 parts; k₂CO₃1.8 parts; BaCO₃1.5 parts; la₂O₃0.8 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃4.5 parts; al (Al)₂O₃4.2 parts of a mixture; b is₂O₃51.9 parts; 1.8 parts of ZnO; SiO 2₂32.8 parts of; na (Na)₂CO₃1.2 parts; k₂CO₃1.3 parts; BaCO₃1.5 parts; la₂O₃0.8 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃3.5 parts; al (Al)₂O₃4.1 parts; b is₂O₃50.8 parts; 4.7 parts of ZnO; SiO 2₂31.6 parts; na (Na)₂CO₃1.5 parts; k₂CO₃1.2 parts; BaCO₃1.6 parts; la₂O₃1.0 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃3.5 parts; al (Al)₂O₃7.6 parts; b is₂O₃49.6 parts; 3.2 parts of ZnO; SiO 2₂30.6 parts; na (Na)₂CO₃1.2 parts; k₂CO₃1.5 parts; BaCO₃1.6 parts; la₂O₃1.0 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃3.2 parts of a mixture; al (Al)₂O₃3.8 parts; b is₂O₃53.6 parts; 3.6 parts of ZnO; SiO 2₂31.4 parts; na (Na)₂CO₃1.4 parts; k₂CO₃0.6 part; BaCO₃1.5 parts; la₂O₃0.9 part.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃4.5 parts; al (Al)₂O₃4.2 parts of a mixture; b is₂O₃45.5 parts; 5.2 parts of ZnO; SiO 2₂35.8 parts of; na (Na)₂CO₃1.2 parts; k₂CO₃0.8 part; BaCO₃1.6 parts; la₂O₃1.2 parts.

In a part of preferred embodiments of the present invention, the glass powder comprises the following raw materials in parts by weight:

Li₂CO₃2.6 parts; al (Al)₂O₃4.3 parts of a mixture; b is₂O₃55.2 parts; 2.1 parts of ZnO; SiO 2₂30.8 parts; na (Na)₂CO₃1.2 parts; k₂CO₃1.1 parts; BaCO₃1.5 parts; la₂O₃1.2 parts.

The above parts by weight are equivalent to the weight percent when the weight is 100.

The preparation of the glass powder is preferably raw material pretreatment, and the pretreatment comprises the following steps: pre-sintering ZnO at 600-700 ℃ and preserving heat for 4-5 h; preferably presintering at 650-700 ℃ and preserving heat for 4-4.5 h; more preferably presintering at 700 ℃ and preserving heat for 4 hours;

Na₂CO₃、K₂CO₃and B₂O₃Drying the mixture in an oven at 100-120 ℃ for 1-2 h respectively; preferably, Na₂CO₃、K₂CO₃And B₂O₃Respectively in an ovenDrying for 1.5-2 h at 110-120 ℃; more preferably, Na₂CO₃、K₂CO₃And B₂O₃Drying in an oven at 120 ℃ for 2h respectively.

After pretreatment, the raw materials are proportioned according to the mass parts and are ball-milled by a wet method. Ball milling the obtained powder by using absolute ethyl alcohol as grinding fluid; the ball-milling ratio is 3:1, and the ball-milling parameter is 300rpm/4 h.

Drying and smelting after ball milling;

drying the slurry obtained by ball milling, sieving by a 80-mesh sieve, putting into a platinum crucible, smelting, and pouring the smelting liquid into pure water to quench glass; the smelting temperature is preferably 1200-1350 ℃.

And smelting and crushing to obtain the glass powder. And smelting the water-quenched glass, and performing ball milling to obtain glass powder with D50 being 2-4 mu m for later use.

The glass powder is Li obtained by smelting and grinding a mixture containing alkali metal and alkaline earth metal₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃A glass system.

The invention provides a low-temperature sintering medium dielectric constant lithium-based microwave dielectric ceramic material. The auxiliary powder comprises rutile TiO 5-10 wt% of the main powder₂Micro-powder; preferably rutile type TiO 6-9 wt% of the main powder₂And (5) micro-powder. The rutile type TiO of the invention₂The particle diameter D50 of the fine powder is 0.5 to 1.0 μm.

The invention provides a preparation method of a low-temperature sintering medium dielectric constant lithium-based microwave dielectric ceramic material, which comprises the following steps:

a main powder body, glass powder and rutile type TiO shown in formula (I)₂Mixing the micro powder, ball milling by a wet method, drying, mixing with a binder, granulating, pressing and sintering to obtain the nano-composite material.

The composition and specific preparation method of the main powder and the glass powder shown in the formula (I) are clearly described above, and are not repeated herein.

Firstly, main powder shown as formula (I), glass powder and rutile type TiO₂Mixing micro powder, and performing wet ball milling, wherein the wet ball milling time is preferably 3-4 h; more preferably 4 h.

And drying the obtained slurry at 120-140 ℃ after wet ball milling. Adding a binder into the dried powder, and sieving the powder with a 80-mesh sieve for granulation. The binder is preferably polyvinyl alcohol; more preferably a 5% aqueous solution of polyvinyl alcohol.

Pressing the granulated powder under the pressure of 140-150 MPa to prepare a product; preferably, the granulated powder is pressed into a product with the diameter of 12mm multiplied by 5mm under the pressure of 150 MPa;

and sintering the product at 850-890 ℃ for 0.5-1 hour to obtain the microwave dielectric ceramic material.

The lithium-based microwave dielectric material with moderate dielectric constant (24.3-28.6), high Qxf value and nearly zero temperature coefficient of resonance frequency (tau f) can be obtained by mixing, molding and sintering the main powder and the auxiliary powder at 850-890 ℃, can be compatible with silver electrodes in co-firing, is used for microwave devices such as chip resonators, antennas, filters and the like, and is ideal low-temperature co-fired ceramic.

The invention provides lithium-based microwave dielectric ceramic which is prepared from the ceramic material or the ceramic material prepared by the preparation method.

The ceramic material and the preparation method thereof have been described clearly in the present invention, and are not described herein again.

The invention provides a microwave device, which is prepared from the ceramic material or the ceramic material prepared by the preparation method.

The microwave device of the present invention includes but is not limited to a chip resonator, an antenna, a filter, etc.

The invention provides a lithium-based microwave dielectric ceramic material, which comprises the following raw materials: a main powder and an auxiliary powder represented by formula (I); the auxiliary powder comprises glass powder accounting for 0.5-1.5 wt% of the main powder and main powder5-10 wt% rutile type TiO₂Micro-powder; li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Formula (I); wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2. The invention is in Li₂CO₃-ZnO-TiO₂By Cu on a system basis²⁺Substituted Zn²⁺To reduce Li₂CO₃-ZnO-TiO₂Presintering temperature and sintering temperature, introducing the glass powder material of the invention to reduce the sintering temperature of the system, introducing Mg²⁺、Nb⁵⁺Substituted Ti⁴⁺Improving the frequency temperature coefficient and introducing TiO₂On the one hand, Li can be increased₂CO₃-ZnO-TiO₂The sintering compactness of the system can be adjusted on the other hand_fThe value is obtained. Cu²⁺The substitution and specification of glass frit successfully enabled Li₂CO₃-ZnO-TiO₂The system can be sintered to be compact and obtain excellent dielectric property after being sintered for 1 hour at 850-890 ℃, so that the material can be co-sintered with an Ag electrode. The lithium-based microwave dielectric ceramic with the dielectric constant in low-temperature sintering has simple chemical composition and preparation process, can be widely used for manufacturing microwave devices such as chip resonators, antennas, filters and the like, and is an ideal low-temperature co-fired ceramic material.

In order to further illustrate the present invention, the following will describe in detail a low-temperature sintering medium dielectric constant lithium-based microwave dielectric ceramic material, a preparation method thereof and a lithium-based microwave dielectric ceramic provided by the present invention with reference to the following examples.

Example 1

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic material and a preparation method thereof. The lithium-based microwave dielectric ceramic material comprises the following raw materials: a main powder and an auxiliary powder. The chemical formula of the main powder is as follows: li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Wherein x is more than or equal to 0 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 0.2; the additional auxiliary powder comprises 0.5-1.5% of glass powder and 5-10% of rutile TiO relative to the main powder₂And (5) micro-powder. WhereinThe glass powder is Li obtained by smelting and grinding a mixture containing alkali metal and alkaline earth metal₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃A glass system. The preparation method comprises the steps of mixing uniformly in a ball mill, drying, granulating, molding and sintering.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂ZnTi₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and preserving heat at 900 ℃ for 4h for pre-sintering to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀1.15 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1350 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀2.16 μm glass frit.

3) Taking a certain amount of synthesized Li₂ZnTi₃O₈Powder of Li in terms of glass powder₂ZnTi₃O₈1.5% of the powder, TiO₂Occupy Li₂ZnTi₃O₈And 5 percent of the powder is prepared. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 890 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.6、Q×f＝63621GHz、τ_f＝-8.66×10^-6ppm/℃。

Example 2

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃Bulk glass powder and TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b for 4 hours by using pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and preserving heat at 900 ℃ for 4h for pre-sintering to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.18 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1350 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀2.25 μm glass frit.

3) Taking a certain amount of synthesized Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈Powder of Li in terms of glass powder₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈1.5% of the powder, TiO₂Occupy Li₂Zn(Ti_0.95(Mg_1/3Nb_2/3)_0.05)₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 890 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.2、Q×f＝49128GHz、τ_f＝-5.6×10^-6ppm/℃。

Example 3

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and auxiliary powder TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and preserving heat at 900 ℃ for 4h for pre-sintering to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.16 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at 1250 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀2.36 μm glass frit.

3) Taking a certain amount of synthesized Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Powder of Li in terms of glass powder₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈1.5% of the powder, TiO₂Occupy Li₂Zn(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. Pressing the granulated powder under 150MPa to obtainThe article of manufacture of (1). And sintering the product at 880 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.8、Q×f＝50126GHz、τ_f＝-2.7×10^-6ppm/℃。

Example 4

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and auxiliary powder TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b for 4 hours by using pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and preserving heat at 900 ℃ for 4h for pre-sintering to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.42 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1350 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀2.86 μm glass frit.

3) Taking a certain amount of synthesized Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈Powder of Li in terms of glass powder₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈1.5% of the powder, TiO₂Occupy Li₂Zn(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈And 6 percent of the powder is prepared. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 880 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝28.2、Q×f＝57986GHz、τ_f＝1.8×10^-6ppm/℃。

Example 5

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and auxiliary powder TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂(Zn_0.975Cu_0.025)Ti₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and pre-sintering at 850 ℃ for 4h to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.36 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1350 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀3.12 μm glass frit.

3) Taking a certain amount of synthesized Li₂(Zn_0.975Cu_0.025)Ti₃O₈Powder of Li in terms of glass powder₂(Zn_0.975Cu_0.025)Ti₃O₈1.5% of the powder, TiO₂Occupy Li₂(Zn_0.975Cu_0.025)Ti₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 875 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.5、Q×f＝59176GHz、τ_f＝-3.6×10^-6ppm/℃。

Example 6

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and auxiliary powder TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂(Zn_0.95Cu_0.05)Ti₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and pre-sintering at 840 ℃ for 4h to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.65 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at 1300 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: on the upper partBall milling the water quenched glass to obtain D₅₀3.12 μm glass frit.

3) Taking a certain amount of synthesized Li₂(Zn_0.95Cu_0.05)Ti₃O₈Powder of Li in terms of glass powder₂(Zn_0.95Cu_0.05)Ti₃O₈1.5% of the powder, TiO₂Occupy Li₂(Zn_0.95Cu_0.05)Ti₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 875 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.3、Q×f＝56319GHz、τ_f＝-4.5×10^-6ppm/℃。

Example 7

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and pre-sintering at 850 ℃ for 4h to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.51 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the dried slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1350 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀3.28 μm glass frit.

3) Taking a certain amount of synthesized Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈Powder of Li in terms of glass powder₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_1/3Nb_2/3)_0.1)₃O₈1% of powder, TiO₂Occupy Li₂(Zn_0.95Cu_0.05)(Ti_0.9(Mg_{1/ 3}Nb_2/3)_0.1)₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 875 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝26.2、Q×f＝58863GHz、τ_f＝-1.3×10^-6ppm/℃。

Example 8

A low-temperature sintered medium-dielectric constant lithium-based microwave dielectric ceramic and a preparation method thereof. The raw material of the lithium-based microwave dielectric ceramic is Li₂(Zn_(1-x)Cu_x)(Ti_(1-y)(Mg_1/3Nb_2/3)_y)₃O₈Main powder and auxiliary powder Li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃System glass powder and auxiliary powder TiO₂And (4) forming.

1) Synthesizing main powder: with purity of Li not less than 99%₂CO₃、ZnO、TiO₂CuO, MgO and Nb₂O₅Is used as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, and presintering MgO with particle size of 40-80nm at 800 deg.C and holding for 4 h;

b. weighing the ingredients: according to Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈Metering and weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking pure water as grinding fluid;

d. drying and pre-sintering: drying the slurry obtained in the step c, sieving by a 80-mesh sieve, pressing into blocks, and pre-sintering at 840 ℃ for 4h to prepare pre-sintered blocks;

e. crushing and pulverizing: the baked blocks are crushed and ball-milled to obtain D₅₀2.21 μm.

2) Preparing glass powder: li₂O-Al₂O₃-B₂O₃-ZnO-SiO₂-Na₂O-K₂O-BaO-La₂O₃The system glass powder is Li with purity not less than 99%₂CO₃、Al₂O₃、B₂O₃、ZnO、SiO₂、Na₂CO₃、K₂CO₃、BaCO₃And La₂O₃Is taken as a main raw material and is carried out according to the following steps:

a. pretreatment of raw materials: presintering ZnO at 700 deg.C and holding for 4h, Na₂CO₃、K₂CO₃And B₂O₃Drying in a drying oven at 120 ℃ for 2h for later use;

b. weighing the ingredients: the weight percentages are as follows:

weighing;

c. wet ball milling: ball-milling the powder obtained in the step b by taking absolute ethyl alcohol as grinding fluid;

d. drying and smelting: drying the slurry obtained in the step c, sieving the dried slurry by a 80-mesh sieve, putting the sieved slurry into a platinum crucible, smelting the platinum crucible at the temperature of 1200 ℃, and pouring the smelting liquid into pure water to quench glass;

e. crushing and pulverizing: ball milling the water quenched glass to obtain D₅₀3.12 μm glass frit.

3) Taking a certain amount of synthesized Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈Powder of Li in terms of glass powder₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈1% of powder, TiO₂Occupy Li₂(Zn_0.9Cu_0.1)(Ti_0.8(Mg_1/3Nb_2/3)_0.2)₃O₈And (5) mixing 8% of the powder. And drying the obtained slurry at 120 ℃ after wet ball milling for 4 hours. Adding 5% polyvinyl alcohol aqueous solution into the dried powder, and sieving with a 80-mesh sieve for granulation. The granulated powder is pressed into the powder under the pressure of 150MPaThe article of manufacture of (1). And sintering the product at 850 ℃ for 1 hour to obtain the microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝25.9、Q×f＝45386GHz、τ_f＝-4.3×10^-6ppm/℃。

FIG. 1 shows the XRD (X-ray diffraction pattern) of example 1 sintered at 890 deg.C, FIG. 2 shows the XRD (X-ray diffraction pattern) of example 7 sintered at 875 deg.C, from which it can be seen that no significant second phase is formed after the addition of the sintering aid and the substitution at the B-position; FIG. 3 is SEM (scanning electron microscope image) of example 1 sintered at 890 ℃, FIG. 4 is SEM (scanning electron microscope image) of example 7 sintered at 875 ℃, and it can be seen that doping with sintering aid and substitution at B site promotes sintering densification, thereby improving Li₂CO₃-ZnO-TiO₂Microwave properties of the system ceramic.

Comparative example 1

Preparing materials: to analyze pure Li₂CO₃ZnO and TiO₂Powder as main raw material, according to Li₂ZnTi₃O₈Proportioning according to a stoichiometric ratio;

ball milling: placing the prepared mixed powder into a resin ball milling tank, taking absolute ethyl alcohol as a dispersing agent and zirconia balls as a grinding medium, and carrying out ball milling for 24 hours at a ball milling rotating speed of 300rpm for 30 min;

drying: putting the tray containing the slurry into a drying oven with the temperature of 75 ℃ for drying;

pre-burning: pre-burning at 900 deg.C for 4 hr to obtain pre-burnt block, and crushing;

taking a certain amount of synthesized Li₂ZnTi₃O₈Powder according to ZnO-La₂O₃-B₂O₃Glass powder of Li₂ZnTi₃O₈1.0 percent of the powder is mixed. And drying the obtained slurry at 75 ℃ after ball milling. Adding a polyvinyl alcohol water-alcohol solution accounting for 5 percent of the weight of the powder into the dried powder, and granulating by a double-layer screen of 40-60 meshes. And pressing the granulation powder into a green body with the height-diameter ratio of 0.4-0.6. Sintering the product at 925 ℃ for 4 hours to obtain Li₂ZnTi₃O₈+1.0％ZnO-La₂O₃-B₂O₃Microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝24.34、Q×f＝41360GHz、τ_f＝-13.4×10^-6ppm/℃。

Comparative example 2

Preparing materials: to analyze pure Li₂CO₃、ZnO、TiO₂And Al₂O₃LiF and CaF₂The powder as starting powder, according to Li_2.1Zn_0.8Al_0.1Ti₃O₈The stoichiometric ratio of the raw materials is weighed and mixed;

ball milling: placing the prepared mixed powder into a resin ball milling tank, and carrying out ball milling for 24 hours by using absolute ethyl alcohol as a dispersing agent and zirconia balls as a grinding medium;

drying: putting the ground slurry after ball milling into a drying oven with the temperature of 75 ℃ for drying;

pre-burning: putting the dried powder into an alumina crucible, preserving heat at 900 ℃ for 4h for pre-sintering, preparing into pre-sintered blocks, and crushing;

secondary ball milling: performing secondary ball milling on the pre-sintered powder according to the ratio of ball materials to alcohol in the primary ball milling;

the resulting slurry was dried at 75 ℃. Taking a certain amount of synthesized Li_2.1Zn_0.8Al_0.1Ti₃O₈Powder according to (LiF/CaF)₂) Occupy Li_2.1Zn_0.8Al_0.1Ti₃O₈2.0 wt% of the powder was dosed. And drying the obtained slurry at 75 ℃ after ball milling. Adding a polyvinyl alcohol water-alcohol solution accounting for 5 percent of the weight of the powder into the dried powder, and granulating by a double-layer screen of 40-60 meshes. And pressing the granulation powder into a green body with the height-diameter ratio of 0.4-0.6. Sintering the green body at 900 ℃ for 4 hours to obtain 0.98Li₂Zn_0.4Co_0.6Ti₃O₈-0.02(LiF/CaF₂) Microwave dielectric ceramic material. The microwave dielectric property of the material is as follows: epsilon_r＝25.77、Q×f＝34547GHz、τ_f＝-8.89×10^-6ppm/℃。

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.