CN105000880A - Li2O-MgO-WO3 ternary low-temperature sintering microwave dielectric ceramic and a preparation method thereof - Google Patents

Abstract

The present invention discloses a Li2O-MgO-WO3 ternary low-temperature sintering microwave dielectric ceramic and a preparation method thereof. The method is as below: weighing original powders of Li2CO3, MgO and WO3 with purity of no less than 99% according to the composition MgLi1.2W0.8O4; conducting wet ball mixing for four hours; drying and pre-calcining in an air atmosphere at 700 DEG C for four hours; then adding a binder in the obtained powder and granulating; compressing and molding; and finally sintering the porcelain at 720-840 DEG C for four hours, so as to obtain the Li2O-MgO-WO3 ternary low-temperature sintering microwave dielectric ceramic. The preparation method is simple, the prepared microwave dielectric ceramic has low sintering temperature (no higher than 840 DEG C), excellent microwave properties: dielectric constant epsilon r of 9-10, Q*f value of up to 20537GHz, and stable Tau f, and has application prospects in the manufacture of resonator, microwave antennas, filters and other microwave devices.

Description

Li 2o-MgO-WO 3ternary can Temperature Firing Microwave Dielectric Ceramics and preparation method thereof

Technical field

The invention belongs to electronic ceramics and manufacture field thereof, particularly a kind of Li used in microwave frequency ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics and preparation method thereof.

Background technology

Microwave-medium ceramics refers to and is applied to as dielectric material in microwave frequency band (mainly UHF, SHF frequency range) circuit, and completes the pottery of one or more functions, is the class new function pottery developed rapidly over nearly 30 years.Microwave-medium ceramics not only can, as the insulated substrate in microwave circuit, also can be used for manufacturing the devices such as microwave dielectric filter resonator.

In recent years, along with microwave mobile communication technology is constantly to high frequency and digitizing future development, also more and more urgent to the requirement of component module.LTCC Technology (LTCC, Low Temperature Co-fired Ceramics) is one of major technique of electronic-component module.The gordian technique of LTCC require microwave dielectric material must excellent performance, there is low sintering temperature (≤900 DEG C) and compatibility can be burnt altogether with Ag electrode.Although current most microwave dielectric ceramic has excellent performance, its sintering temperature too high (>=1300 DEG C), as (Zr, Sn) TiO ₄, Ba (Zn _1/3ta _2/3) O ₃, Ba (Mg _1/3ta _2/3) O ₃deng, therefore cannot be applied on LTCC device.Therefore increasing research be placed on and explored that sintering temperature is low, excellent performance and can realize burning altogether on the material system of compatibility with Ag electrode.

Information technology develop rapidly in recent years, the demand in miniaturization, lightness, high reliability, high integration and low cost such as communication class electronic product, Military Electronics complete machine, has higher requirement to the microwave device based on microwave-medium ceramics.Can effectively reduce device volume with the multi-layer structure design based on LTCC (low-temperature co-fired ceramic, LTCC) technology, be the important technical realizing these demands.

LTCC technology is a kind of integrated assembly technology of the multi-crossed disciplines attracted people's attention, and relates to the wide spectrums such as circuit layout, Materials science, microwave technology.It is the type material technology developed by Hughes Electronics the eighties in 20th century at first, utilizes low-temperature sintered ceramics material, according to the patterning of design, by one-time sintering technology such as substrate, electronic component, electrode materialss, substantially increases production efficiency.Compared with other assembly integration technologies, LTCC technology has many advantages: the sintering temperature of LTCC technology, generally lower than 950 DEG C, can adopt the high conductivity metal such as gold and silver, copper as conducting medium, reduces technology difficulty and improve signaling rate; The specific inductivity of LTCC material can change within a large range, makes circuit layout more flexible; Temperature profile is more outstanding, as having less thermal expansivity, less temperature coefficient of resonance frequency, can adapt to big current and high-temperature stability requirement; Reliability is higher, can be used for severe environment; Thinner live width and distance between centers of tracks can be obtained, improve integrated level.

Microwave dielectric ceramic materials as one of the critical material of LTCC technology, should have low-loss (high Q × f value), nearly zero temperature coefficient of resonance frequency (temperature-stable: τ _f ≈ 0ppm/ DEG C) and sintering temperature and low (<960 DEG C), can with the characteristic of Ag or Cu electrode matching co-firing.But, the microwave dielectric ceramic materials of the overwhelming majority does not have the temperature coefficient of resonance frequency of sintering temperature and low and nearly zero, be not suitable for the requirement of LTCC technology, therefore R and D low-temperature sintering temperature-stabilized microwave medium ceramic material system just becomes particularly important.

In sum, the develop rapidly of microwave technology has promoted microwave device to miniaturization, integrated development.LTCC technology becomes Current electronic component integration, modular preferred manner with the electricity of its excellence, calorifics, mechanical characteristics, is widely used in the fields such as aerospace industry, military affairs, radio communication, global positioning system (GPS), WLAN (wireless local area network) and automobile.Therefore, chemical constitution and preparation technology is simple, sintering temperature is low, have temperature stability, microwave dielectric property excellent and the novel microwave dielectric ceramic material that can burn altogether with copper or silver electrode has broad application prospects.

Summary of the invention

The object of this invention is to provide a kind of Li ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics and preparation method thereof.

Li of the present invention ₂o-MgO-WO ₃ternary can the chemical constitution formula of Temperature Firing Microwave Dielectric Ceramics be: MgLi _1.2w _0.8o ₄.

Prepare above-mentioned Li ₂o-MgO-WO ₃ternary can the concrete steps of Temperature Firing Microwave Dielectric Ceramics be:

(1) with the Li of purity>=99% ₂cO ₃, MgO and WO ₃for starting powder, by MgLi _1.2w _0.8o ₄composition weigh batching.

(2) the raw material wet ball-milling that step (1) takes being mixed 4 hours, is ball-milling medium with ethanol, pre-burning 4 hours under 700 DEG C of air atmospheres after drying, obtained powder.

(3) in the powder that step (2) is obtained, add binding agent and after granulation, compression moulding, finally sinter 4 hours by porcelain at 720 ~ 840 DEG C, namely obtain Li ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics; Described binding agent adopts mass concentration to be the polyvinyl alcohol water solution of 5%, and dosage accounts for 7% of powder total amount.

Preparation method of the present invention is simple, the microwave-medium ceramics of preparation, sintering temperature low (≤840 DEG C), and microwave property is excellent: specific inductivity ( ε _r ) be 9 ~ 10, q × fbe worth up to 20537GHz and τ _f stable, there is application prospect at the manufacture view of the microwave devices such as resonator, microwave antenna, wave filter.

Embodiment

embodiment 1:

(1) be the Li of 99.9% with purity ₂cO ₃, MgO and WO ₃for starting powder, by MgLi _1.2w _0.8o ₄composition weigh batching.

(2) the raw material wet ball-milling that step (1) takes being mixed 4 hours, is ball-milling medium with ethanol, pre-burning 4 hours under 700 DEG C of air atmospheres after drying, obtained powder.

(3) in the powder that step (2) is obtained, add binding agent and after granulation, compression moulding, finally sinter 4 hours by porcelain at 720 DEG C, namely obtain Li ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics; Described binding agent adopts mass concentration to be the polyvinyl alcohol water solution of 5%, and dosage accounts for 7% of powder total amount.

embodiment 2:

Change sintering temperature in step (3) into 740 DEG C, other and embodiment 1 are consistent.

embodiment 3:

Change sintering temperature in step (3) into 760 DEG C, other and embodiment 1 are consistent.

embodiment 4:

Change sintering temperature in step (3) into 800 DEG C, other and embodiment 1 are consistent.

embodiment 5:

Change sintering temperature in step (3) into 820 DEG C, other and embodiment 1 are consistent.

embodiment 6:

Change sintering temperature in step (3) into 840 DEG C, other and embodiment 1 are consistent.

Table 1 shows Li prepared by embodiment 1 ~ 6 ₂o-MgO-WO ₃ternary can the microwave dielectric property of Temperature Firing Microwave Dielectric Ceramics.The evaluation of microwave dielectric property is carried out by cylindrical dielectric resonator method.

The microwave dielectric property of microwave-medium ceramics prepared by the different sintering temperature of table 1

The pottery prepared of above-described embodiment can the potential manufacture for microwave devices such as LTCC medium substrate, resonator and wave filters, also holds out broad prospects in the systematic difference such as mobile communication and satellite communications.

Claims (2)

1. a Li ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics, it is characterized in that this Li ₂o-MgO-WO ₃ternary can the chemical constitution formula of Temperature Firing Microwave Dielectric Ceramics be MgLi _1.2w _0.8o ₄.

2. Li according to claim 1 ₂o-MgO-WO ₃ternary can the preparation method of Temperature Firing Microwave Dielectric Ceramics, it is characterized in that concrete steps are:

(1) with the Li of purity>=99% ₂cO ₃, MgO and WO ₃for starting powder, by MgLi _1.2w _0.8o ₄composition weigh batching;

(2) the raw material wet ball-milling that step (1) takes being mixed 4 hours, is ball-milling medium with ethanol, pre-burning 4 hours under 700 DEG C of air atmospheres after drying, obtained powder;

(3) in the powder that step (2) is obtained, add binding agent and after granulation, compression moulding, finally sinter 4 hours by porcelain at 720 ~ 840 DEG C, namely obtain Li ₂o-MgO-WO ₃ternary can Temperature Firing Microwave Dielectric Ceramics; Described binding agent adopts mass concentration to be the polyvinyl alcohol water solution of 5%, and dosage accounts for 7% of powder total amount.