CN111646796A - Low-temperature sintered low-dielectric microwave ceramic material Sr2VxO7And method for preparing the same - Google Patents

Abstract

The invention belongs to the field of electronic ceramics and manufacture thereof, relates to a microwave ceramic material, and particularly provides a low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇And a preparation method thereof, which is used for further improving the Sr of the microwave ceramic material₂V₂O₇The performance of (c). The invention adjusts the content of vanadium to obtain the microwave ceramic material Sr₂V_xO₇、1.80≤x<2.00; the microwave ceramic material keeps the main crystal phase as Sr₂V₂O₇While introducing a secondary crystal phase Sr₃(VO₄)₂The sintering temperature (900-950 ℃) is effectively reduced, and the microwave dielectric properties of the microwave ceramic material are greatly improved, namely the dielectric constant is 9-13, the Q × f value is 25000-37000 GHz, the temperature coefficient of the resonance frequency is-62 to-18 ppm/DEG C, and particularly the Q × f value is obviously improvedThe method has the advantages of low intrinsic sintering temperature, no need of adding any sintering aid, simple preparation process, low cost of all raw materials, rich sources and contribution to industrial production.

Description

Low-temperature sintered low-dielectric microwave ceramic material Sr2VxO7And method for preparing the same

Technical Field

The invention belongs to the field of electronic ceramics and manufacture thereof, relates to a microwave ceramic material, and particularly relates to a low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇And a method for preparing the same.

Background

With the expansion of the operating frequency range of 5G communication technology and advanced radar systems to millimeter waves, microwave ceramic materials used as substrates are generally required to have low sintering temperature, high quality factor and low dielectric constant in order to achieve fast signal transmission and minimize cross-coupling between the substrate and the conductor.

In recent years, vanadate microwave dielectric ceramics attract wide attention because of low inherent sintering temperature, low dielectric constant and simple synthesis process. A great deal of research has been carried out on low-temperature sintered vanadate ceramics at home and abroad, for example, Mi-Ri Joung et al published in 2009 on J AM CERAM SOC by "Formation Process and Microwave dielectric Properties of the R₂V₂O₇(R ═ Ba, Sr, and Ca) Ceramics "discloses the preparation of Sr at a sintering temperature of 950 ℃₂V₂O₇A microwave dielectric ceramic having properties of_r＝9.09，Q×f＝16362GHz，τ_f＝-30.35ppm/℃。

Based on this background, the present invention provides a low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇And a method for preparing the same.

Disclosure of Invention

The invention aims to provide a low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇And a preparation method thereof, which is used for further improving the Sr of the microwave ceramic material₂V₂O₇The performance of the sintering aid realizes low-temperature sintering at 900-950 ℃ without a sintering aid. The chemical formula of the microwave ceramic material is Sr₂V_xO₇In the presence of a bi-crystalline phase Sr₂V₂O₇、Sr₃(VO₄)₂The sintering temperature is reduced by adjusting the content of vanadium, and excellent microwave dielectric properties are obtained, wherein the dielectric constant is 9-13, the Q × f value is 25000-36500 GHz, and the temperature coefficient of resonance frequency is-62 to-18 ppm/DEG C.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇The method is characterized in that: the chemical formula of the microwave ceramic material is Sr₂V_xO₇Wherein x is more than or equal to 1.80<2.00。

Further, the microwave ceramic material contains a main crystal phase Sr₂V₂O₇And a secondary crystal phase Sr₃(VO₄)₂Respectively belong to the triclinic system and the hexagonal system, the paracrystalline phase Sr₃(VO₄)₂The ratio of (A) to (B) is 11 to 24 wt%.

Furthermore, the sintering temperature of the microwave ceramic material is 900-950 ℃, the dielectric constant is 9-13, the Qxf value is 25000-36500 GHz, and the temperature coefficient of the resonance frequency is-62 to-18 ppm/DEG C.

The low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇The preparation method is characterized by comprising the following steps:

step 1, batching: using analytically pure SrCO₃、V₂O₅According to the chemical composition formula Sr₂V_xO₇Is prepared according to the molar ratio of (1.80) to (x)<2.00；

Step 2, primary ball milling: taking zirconium balls as grinding balls, taking deionized water as a ball milling medium, and taking the zirconium balls as materials according to the mass ratio: ball: wet-milling the mixed raw materials in a nylon tank for 24 hours at a water ratio of 1:5:2, discharging after ball milling, and drying the slurry in an oven at 100 ℃;

and step 3, sieving: sieving the dried material with a 60-mesh sieve;

step 4, pre-burning: roasting the screened material in air at 750-850 ℃ for 3 hours;

step 5, secondary ball milling: taking a zirconium ball as a grinding ball, taking deionized water as a medium, and pre-sintering the materials according to the mass ratio: ball: putting the mixture into a nylon tank in a ratio of 1:5:2, wet-milling and mixing for 12 hours, discharging materials after ball milling, and putting the slurry into an oven to dry at 100 ℃;

and 6, granulating and forming: granulating the dried material, adopting 5 wt% of polyvinyl alcohol solution as a binder, and pressing the mixture into a green body under the pressure of 20 MPa;

and 7, sintering: and (3) insulating the green body in air at the temperature of 450-550 ℃ for 1-3 hours, and sintering at the temperature of 900-950 ℃ for 9 hours to obtain the low-temperature sintered low-dielectric microwave ceramic material.

The invention has the beneficial effects that:

1. the invention adjusts the content of vanadium (x is more than or equal to 1.80)<2.00) to obtain microwave ceramic material Sr₂V_xO₇Maintaining the main crystal phase as Sr₂V₂O₇While introducing a secondary crystal phase Sr₃(VO₄)₂Wherein the secondary crystal phase Sr₃(VO₄)₂The proportion of (A) is 11-24 wt%; secondary crystal phase Sr₃(V O₄)₂The introduction of the microwave ceramic material effectively reduces the sintering temperature (900-950 ℃), and simultaneously greatly improves the microwave dielectric properties of the microwave ceramic material, wherein the dielectric constant is 9-13, the Q × f value is 25000-37000 GHz, and the temperature coefficient of resonance frequency is-62 to-18 ppm/DEG C, particularly the Q × f value is obviously improved, the loss of the material is reduced, and the microwave ceramic material is more beneficial to the development of microwave devices towards miniaturization, integration and modularization.

2. The microwave ceramic material provided by the invention has low intrinsic sintering temperature (900-950 ℃) and does not need to be added with any sintering aid, so that dielectric property deterioration, density and strength reduction of the material caused by the sintering aid are avoided.

3. The microwave ceramic material provided by the invention has the advantages of simple preparation process, easy control of formed phases, uniform grain growth and guarantee of excellent microwave dielectric property; all the raw materials have low cost and rich sources, and can be widely applied to the manufacture of low-temperature co-fired ceramic systems, multilayer dielectric resonators and related ceramic substrates.

Drawings

FIG. 1 shows a microwave ceramic material Sr prepared in example 2₂V_xO₇XRD pattern of (a).

FIG. 2 is a diagram of a microwave ceramic material Sr prepared in example 2₂V_xO₇SEM image of (d).

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides 4 embodiments in total, and each embodiment provides a low-temperature sintering low-dielectric microwave ceramic material containing a main crystal phase Sr₂V₂O₇And a secondary crystal phase Sr₃(VO₄)₂Belonging to the triclinic system and the hexagonal system respectively; has a chemical formula of Sr₂V_xO₇Wherein x is 1.80, 1.85, 1.90 and 1.95.

The preparation method of the ultralow temperature sintered microwave ceramic material comprises the following steps:

step 1, batching: using analytically pure SrCO₃、V₂O₅According to the chemical composition formula Sr₂V_xO₇The molar ratio of (1) to (1.80), (1.85), (1.90), (1.95);

step 2, primary ball milling: taking zirconium balls as grinding balls, taking deionized water as a ball milling medium, and mixing the following materials: ball: wet-milling the mixed raw materials in a nylon tank for 24 hours at a water ratio of 1:5:2, discharging after ball milling, and drying the slurry in an oven at 100 ℃;

and step 3, sieving: sieving the dried material with a 60-mesh sieve;

step 4, pre-burning: roasting the screened material in air at 750-850 ℃ for 3 hours;

step 5, secondary ball milling: taking a zirconium ball as a grinding ball, taking deionized water as a medium, and preparing a pre-sintered material: ball: putting the mixture into a nylon tank in a ratio of 1:5:2, wet-milling and mixing for 12 hours, discharging materials after ball milling, and putting the slurry into an oven to dry at 100 ℃;

and 6, granulating and forming: granulating the dried material, adopting 5 wt% of polyvinyl alcohol solution as a binder, and pressing the mixture into a green body under the pressure of 20 MPa;

and 7, sintering: and (3) insulating the green body in air at the temperature of 450-550 ℃ for 1-3 hours, and sintering at the temperature of 900-950 ℃ for 9 hours to obtain the low-temperature sintered low-dielectric microwave ceramic material.

The specific published parameters and microwave dielectric properties of the above 4 examples are shown in the table:

wherein, when x is 1.9, the low-temperature sintered low-dielectric microwave ceramic material Sr is used₂V_1.90O₇The performance is optimal, and the XRD pattern and the SEM pattern are respectively shown in figures 1 and 2 when the performance is tested, and the analysis of the XRD result shows that Sr is shown₂V₂O₇(triclinic system) and Sr₃(VO₄)₂The existence of two crystal phases (hexagonal system) and the presence of plate-like crystal grains and elongated crystal grains, corresponding to Sr, respectively, can be seen in the SEM picture₂V₂O₇Phase and Sr₃(VO₄)₂And (4) phase(s).

While the invention has been described with reference to specific embodiments, any feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise; all of the disclosed features, or all of the method or process steps, may be combined in any combination, except mutually exclusive features and/or steps.

Claims (4)

1. Low-temperature sintered low-dielectric microwave ceramic material Sr₂V_xO₇The method is characterized in that: the chemical formula of the microwave ceramic material is Sr₂V_xO₇Wherein x is more than or equal to 1.80<2.00。

2. The low-temperature sintered low-dielectric microwave ceramic material Sr as in claim 1₂V_xO₇Characterized in that the microwave ceramic material contains a main crystal phase Sr₂V₂O₇And a secondary crystal phase Sr₃(VO₄)₂The main crystal phase Sr₂V₂O₇And a secondary crystal phase Sr₃(VO₄)₂The proportion of (B) is 11-24 wt%.

3. The low-temperature sintered low-dielectric microwave ceramic material Sr as in claim 1₂V_xO₇It is characterized in that the microwave ceramicThe sintering temperature of the ceramic material is 900-950 ℃, the dielectric constant is 9-13, the Q × f value is 25000-36500 GHz, and the temperature coefficient of the resonance frequency is-62 to-18 ppm/DEG C.

4. The low-temperature sintered low-dielectric microwave ceramic material Sr as in claim 1₂V_xO₇The preparation method is characterized by comprising the following steps:

step 1, batching: using analytically pure SrCO₃、V₂O₅According to the chemical composition formula Sr₂V_xO₇Is prepared according to the molar ratio of (1.80) to (x)<2.00；

Step 2, primary ball milling: taking zirconium balls as grinding balls, taking deionized water as a ball milling medium, and taking the zirconium balls as materials according to the mass ratio: ball: wet-milling the mixed raw materials in a nylon tank for 24 hours at a water ratio of 1:5:2, discharging after ball milling, and drying the slurry in an oven at 100 ℃;

and step 3, sieving: sieving the dried material with a 60-mesh sieve;

step 4, pre-burning: roasting the screened material in air at 750-850 ℃ for 3 hours;

step 5, secondary ball milling: taking a zirconium ball as a grinding ball, deionized water as a medium, and taking the zirconium ball as a pre-sintering material according to the mass ratio: ball: putting the mixture into a nylon tank in a ratio of 1:5:2, wet-milling and mixing for 12 hours, discharging materials after ball milling, and putting the slurry into an oven to dry at 100 ℃;

and 6, granulating and forming: granulating the dried material, adopting 5 wt% of polyvinyl alcohol solution as a binder, and pressing the mixture into a green body under the pressure of 20 MPa;

and 7, sintering: and (3) insulating the green body in air at the temperature of 450-550 ℃ for 1-3 hours, and sintering at the temperature of 900-950 ℃ for 9 hours to obtain the low-temperature sintered low-dielectric microwave ceramic material.

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