CN103922724A - Microwave dielectric ceramic with high quality factor and preparation method thereof - Google Patents

Abstract

The invention discloses a microwave dielectric ceramic with a high quality factor and a preparation method thereof, the expression of which is Mg _1.6 Ti _1.2 O ₄ ; first, MgO and TiO ₂ are mixed according to the stoichiometric formula Mg _1.6 Ti _1.2 O ₄ , and ball milled 4-24 hours; then dry the raw materials at 100-120°C, and pre-fire at 900-1150°C; after granulation and pressure molding, sinter at 1325°C-1425°C. The microwave dielectric ceramic of the present invention has a dielectric constant ε _r of 15.9-16.6, a quality factor Q×f of 149000-156000 GHz, and a resonant frequency temperature coefficient τ _f of -42-52×10 ^-6 /°C. The invention saves the secondary ball milling of the powder, simplifies the preparation process and saves the production cost.

Description

Microwave dielectric ceramic with high quality factor and preparation method thereof

technical field

The invention belongs to a ceramic composition characterized by components, in particular to a microwave dielectric ceramic with a chemical formula of Mg _1.6 Ti _1.2 O ₄ having low loss and high quality factor and a preparation method thereof.

Background technique

With the development of microwave communication technology in the past ten years, especially the rapid development of mobile communication and satellite communication technology, traditional metal cavity resonators can no longer meet the needs of applications, and the market is corresponding to new microwave components such as dielectric resonators and dielectric filters. There is an increasing demand for microwave dielectric ceramics for devices. The basic requirements of microwave dielectric ceramic materials are: suitable dielectric constant, lower dielectric loss (higher quality factor Q value) and smaller frequency temperature coefficient.

With the continuous development of ceramic materials, in order to meet different applications, various new materials with excellent performance are emerging. MgO-TiO ₂ series ceramic materials have attracted extensive attention of researchers from various countries due to their excellent dielectric properties. The dielectric properties of Mg _1.6 Ti _1.2 O ₄ microwave dielectric ceramic materials have not been reported at home and abroad.

Contents of the invention

The purpose of the present invention is to prepare a kind of Mg _1.6 Ti _1.2 O ₄ with high quality factor by simple solid-phase method using MgO and TiO ₂ as raw materials in order to adapt to the needs of the continuous development of electronic information technology towards high frequency and digitalization. Microwave dielectric ceramic materials.

The present invention is realized through the following technical solutions.

Using MgO and TiO ₂ as raw materials, the target composition expression is Mg _1.6 Ti _1.2 O ₄ .

The specific preparation method is as follows:

(1) Mix MgO and TiO ₂ according to the stoichiometric formula Mg _1.6 Ti _1.2 O ₄ ; put the powder into a polyester tank, add deionized water and zirconium balls, and ball mill for 4 to 24 hours;

(2) Put the ball-milled raw materials in step (1) into a drying oven, dry at 100-120°C, and pass through a 40-mesh sieve;

(3) Put the dried and sieved powder into a medium-temperature furnace, pre-fire at 900-1150°C, and keep warm for 2-8 hours;

(4) Granulate the pre-fired powder in step (3) plus paraffin wax with a mass percentage of 8% to 10% as a binder, pass through an 80-mesh sieve, and use a powder tablet press with a pressure of 4 to 8 MPa to make granules. into a green body;

(5) Sintering the green body in step (4) at 1325°C-1425°C and keeping it warm for 2-8 hours to produce a microwave dielectric ceramic with a high quality factor.

The step (1) uses a planetary ball mill for ball milling, and the rotational speed of the ball mill is 600 rpm.

The mass ratio of the powder in the step (1) to deionized water and zirconium balls is 1:1:1.

The green body in the step (4) has a diameter of 10 mm and a thickness of 5 mm.

The preferred sintering temperature of the step (5) is 1400°C.

The invention uses MgO and TiO ₂ as raw materials to prepare a novel microwave dielectric ceramic material Mg _1.6 Ti _1.2 O ₄ with a high quality factor through a simple solid phase method. Its dielectric constant ε _r is 15.9-16.6, quality factor Q×f is 149000-156000 GHz, and resonant frequency temperature coefficient τ _f is -42-52×10 ^-6 /°C. The invention saves the secondary ball milling of the powder, simplifies the preparation process of the material, and saves the production cost.

Detailed ways

The invention uses MgO (analytical pure) and TiO ₂ (analytical pure) as initial raw materials, and prepares microwave dielectric ceramics through a simple solid phase method. The specific implementation steps are as follows:

1. Mix MgO and TiO ₂ according to the stoichiometric ratio of Mg _1.6 Ti _1.2 O ₄ , and the ratio of raw materials is: 4.0213gMgO, 5.9788gTiO ₂ . Put about 10g of mixed powder into a polyester tank, add 200ml of deionized water, add 150g of zirconium balls, and mill on a planetary ball mill for 12 hours at a speed of 600 rpm;

2. Place the ball-milled raw materials in a drying oven, dry them at 100-120°C, and then pass them through a 40-mesh sieve;

3. Put the dried and sieved powder into a medium-temperature furnace, pre-fire at 900-1150°C, and keep it warm for 4 hours;

4. Add 8% paraffin wax binder to the pre-fired powder for granulation. After passing through an 80-mesh sieve, use a powder tablet press to compress the powder into a diameter of 10 mm and a thickness of 10 mm under a pressure of 4 MPa. A green body of about 5 mm;

5. Sinter the green body at 1325-1425°C and keep it warm for 4 hours to make microwave dielectric ceramics with high quality factor.

The microwave characteristics of the obtained products were tested by a network analyzer.

The main process parameters and microwave dielectric properties of specific embodiments are shown in Table 1.

Table 1

Claims (5)

1. a microwave-medium ceramics with high quality factor, its expression formula is Mg _1.6ti _1.2o ₄;

This has the preparation method of the microwave-medium ceramics of high quality factor, and concrete implementation step is as follows:

(1) by MgO, TiO ₂press stoichiometric equation Mg _1.6ti _1.2o ₄prepare burden; Powder is put into polyester tank, add after deionized water and zirconium ball ball milling 4～24 hours;

(2) raw material after step (1) ball milling is put into loft drier, in 100～120 ℃ of oven dry, then cross 40 mesh sieves;

(3) powder after drying, sieving is put into moderate oven, in 900～1150 ℃ of pre-burnings, is incubated 2～8 hours;

(4) paraffin that is 8%～10% using the additional mass percent of powder after step (3) pre-burning carries out granulation as tackiness agent, crosses 80 mesh sieves, with powder compressing machine, with the pressure of 4～8MPa, makes green compact;

(5) by the green compact of step (4) in 1325 ℃ of-1425 ℃ of sintering, be incubated 2～8 hours, make the microwave-medium ceramics with high quality factor.

2. the microwave-medium ceramics with high quality factor according to claim 1, is characterized in that, described step (1) adopts planetary ball mill to carry out ball milling, and drum's speed of rotation is 600 revs/min.

3. the microwave-medium ceramics with high quality factor according to claim 1, is characterized in that, the mass ratio of the powder of described step (1) and deionized water and zirconium ball is 1 ︰ 1 ︰ 1.

4. the microwave-medium ceramics with high quality factor according to claim 1, is characterized in that, the green compact diameter of described step (4) is 10mm, and thickness is 5mm.

5. the microwave-medium ceramics with high quality factor according to claim 1, is characterized in that, the preferred sintering temperature of described step (5) is 1400 ℃.