CN105000882A - Low-inherent-sintering-temperature low-loss-temperature stable microwave dielectric ceramic material - Google Patents

Abstract

The invention discloses a microwave dielectric ceramic material with low inherent sintering temperature, low loss and stable temperature. Its chemical formula is _{0.6MgMoO 4 +} 0.4TiO ₂ ; Dry at ~120°C and sieve; then pre-fire at 700-850°C, and pre-fire TiO ₂ powder at 800-950°C; mix the two powders according to the stoichiometric formula 0.6MgMoO ₄ +0.4TiO ₂ , After ball milling, drying, and sieving, press into a green body; the green body is sintered at 800 ° C to 950 ° C to make microwave dielectric ceramics. The electric constant ε _r of the present invention is 8.17-9.78, the quality factor Qf is 41585-53557 GHz, and the temperature coefficient τ _f of the resonant frequency is -75.45--62.87×10 ^-6 /°C; the present invention simplifies the preparation process and saves time costs and energy costs.

Description

A low intrinsic sintering temperature and low loss temperature stable microwave dielectric ceramic material

technical field

The invention belongs to a ceramic composition characterized by components, in particular to a microwave dielectric ceramic with a chemical formula of 0.6MgMoO ₄ +0.4TiO ₂ , which has a low sintering temperature and a medium dielectric constant and a preparation method thereof.

Background technique

With the rapid development of wireless communication technology in the 21st century, electronic technology is gradually moving towards miniaturization, integration, surface assembly, multi-dimensionality and high frequency. Low Temperature Co-fired Ceramics (LTCC) technology is a key way to facilitate this development trend. LTCC technology mainly includes the following three aspects: materials, design, and process and equipment. Among them, the material is the basis for producing LTCC devices. For microwave dielectric materials, the main requirements of LTCC technology are as follows: lower sintering temperature (below 950°C), appropriate dielectric constant, lower dielectric loss (higher quality factor Q value) and near zero The resonant frequency temperature coefficient.

At present, the sintering temperature of most microwave dielectric ceramics with excellent microwave dielectric properties (such as: BaTi ₄ O ₉ , Ba ₂ Ti ₉ O ₂₀ , etc.) is relatively high, generally above 1300 ° C, much higher than that of Cu and Ag It is difficult to meet the requirements of low temperature co-firing. In order to reduce the sintering temperature of microwave dielectric ceramic materials, a certain amount of low melting point oxide or glass is generally added to the existing materials, but for those materials with inherently higher sintering temperature, it is often necessary to add a large amount of low melting point sintering Additives can reduce the sintering temperature, which will damage the microwave dielectric properties to varying degrees, such as increased loss, increased temperature coefficient, etc., so that it is difficult to achieve both low temperature and excellent microwave dielectric properties. However, for microwave dielectric ceramics with low intrinsic sintering temperature, the excellent microwave dielectric properties of the material can be maintained at the same time due to the lower intrinsic sintering temperature during the sintering process. Therefore, exploring new materials with low intrinsic sintering temperature has become a hot spot in the research of microwave dielectric materials in recent years.

Contents of the invention

The purpose of the present invention is to adjust the resonant frequency temperature coefficient of MgMoO ₄ microwave dielectric ceramics with low intrinsic sintering temperature, so as to meet the needs of the continuous development of electronic information technology in the direction of high frequency and digitalization. Using MgO, MoO ₃ , TiO ₂ as raw materials, a 0.6MgMoO ₄ +0.4TiO ₂ microwave dielectric ceramic material with high quality factor was prepared by a simple solid-state method.

The present invention is realized through the following technical solutions.

A low intrinsic sintering temperature, low loss and temperature stable microwave dielectric ceramic material, the chemical formula of which is: 0.6MgMoO ₄ +0.4TiO ₂ ;

The preparation method of the microwave dielectric ceramic material, the specific implementation steps are as follows:

(1) Mix MgO and MoO ₃ according to the stoichiometric formula MgMoO ₄ ; put the powder into a polyester tank, add deionized water and zirconium balls, and ball mill for 4 to 8 hours;

(2) Put the ball-milled powder 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 in step (2) into a medium temperature furnace, pre-fire at 700-850°C, keep it warm for 4-8 hours, and pre-fire the _TiO2 powder at 800-950°C , keep warm for 2 to 4 hours;

(4) Mix the two powders pre-calcined in step (3) according to the stoichiometric formula 0.6MgMoO ₄ +0.4TiO ₂ , put them into a ball mill jar, add zirconia balls and deionized water, and ball mill for 9 to 12 hours , dried, sieved, and then pressed into a green body with a powder tablet press at a pressure of 5-9 MPa;

(5) Sintering the green body in step (4) at 800° C. to 950° C. and keeping it warm for 2 to 8 hours to produce a low-loss temperature-stable microwave dielectric ceramic.

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

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

The preferred sintering temperature of the step (5) is 900°C.

The invention prepares a novel microwave dielectric ceramic material 0.6MgMoO ₄ +0.4TiO ₂ through a simple solid phase method. Its dielectric constant ε _r is 8.17~9.78, quality factor Qf is 41585~53557GHz, and resonant frequency temperature coefficient τ _f is -75.45~-62.87×10 ^-6 /℃. The invention simplifies the preparation process and saves time cost and energy cost.

Detailed ways

The invention uses MgO (analytical pure), MoO ₃ (analytical pure) and TiO ₂ (analytic pure) as initial raw materials, and prepares microwave dielectric ceramics 0.6MgMoO ₄ +0.4TiO ₂ through a simple solid phase method. The specific implementation steps are as follows:

1. Mix MgO and MoO ₃ according to the stoichiometric formula MgMoO ₄ , the powder ratio is: 3.2813g MgO, 11.7186g MoO ₃ , mix the above powders and put them into a polyester tank, add 200ml of deionized water, After adding 150g of zirconium balls, ball mill on a planetary ball mill for 6 hours at a speed of 600 rpm;

2. Put the ball-milled raw materials in a drying oven, dry them at 100°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 750°C, and keep warm for 4 hours, and pre-burn TiO ₂ at 900°C, and keep warm for 3 hours;

4. Mix the two powders pre-fired in step 3 according to the stoichiometric formula 0.6MgMoO ₄ +0.4TiO ₂ , put them into a ball mill jar, add zirconia balls and deionized water, ball mill for 12 hours, dry and pass Sieve, and then use a powder tablet press to press into a green body with a pressure of 6MPa;

5. The green body is sintered at 800-950°C and kept for 6 hours to make low-loss and temperature-stable microwave dielectric ceramics.

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

The relevant process parameters and microwave dielectric properties of specific embodiments of the present invention are shown in Table 1.

Table 1

Claims (4)

1. a low intrinsic sintering temperature low-loss temperature-stabilized microwave medium ceramic material, its chemical formula is: 0.6MgMoO ₄+ 0.4TiO ₂;

The preparation method of this microwave dielectric ceramic materials, concrete implementation step is as follows:

(1) by MgO, MoO ₃stoichiometrically formula MgMoO ₄prepare burden; Powder is put into polyester tank, after adding deionized water and zirconium ball, ball milling 4 ~ 8 hours;

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

(3) step (2) is dried, sieve after powder put into moderate oven, in 700 ~ 850 DEG C of pre-burnings, be incubated 4 ~ 8 hours, separately by TiO ₂powder, in 800 ~ 950 DEG C of pre-burnings, is incubated 2 ~ 4 hours;

(4) by two kinds of powder stoichiometrically formula 0.6MgMoO after step (3) pre-burning ₄+ 0.4TiO ₂prepare burden, put into ball grinder, add zirconia ball and deionized water, ball milling 9 ~ 12 hours, sieves after oven dry, then is pressed into base substrate with powder compressing machine with the pressure of 5 ~ 9MPa;

(5) by the base substrate of step (4) in 800 DEG C ~ 950 DEG C sintering, be incubated 2 ~ 8 hours, make the microwave-medium ceramics of low-loss temperature-stabilized.

2. the low intrinsic sintering temperature low-loss temperature-stabilized microwave medium ceramic material of one according to claim 1, is characterized by, and described step (1) adopts planetary ball mill to carry out ball milling, and drum's speed of rotation is 600 revs/min.

3. the low intrinsic sintering temperature low-loss temperature-stabilized microwave medium ceramic material of one according to claim 1, is characterized by, and the green compact diameter of described step (4) is 10mm, and thickness is 5mm.

4. the low intrinsic sintering temperature low-loss temperature-stabilized microwave medium ceramic material of one according to claim 1, is characterized by, and the preferred sintering temperature of described step (5) is 900 DEG C.