CN103332932B - Low-temperature sintered vanadate microwave dielectric ceramic BaZnV2O7 and preparation method thereof - Google Patents

Abstract

The invention discloses low-temperature sintered vanadate microwave dielectric ceramic BaZnV2O7 and a preparation method thereof. The composition of the low-temperature sintered vanadate microwave dielectric ceramic material is BaZnV2O7. The preparation method comprises the following steps of: (1) weighting the original powder of BaCO3 with the purity of above 99.9%, ZnO with the purity of above 99.9% and V2O5 with the purity of above 99.9% according to the chemical formula of the BaZnV2O7, and burdening; (2) carrying out wet-type ball milling on the raw materials obtained in the step (1) and mixing for 12 hours, wherein distilled water is used as a solvent, drying and then presintering for 6 hours at 750 DEG C atmosphere; (3) adding a binging agent to the powder prepared in the step (2), pelleting, then carrying out compression molding, and finally sintering for 4 hours at 850-900 DEG C atmosphere, wherein a polyvinyl alcohol with the mass concentration of 5% is used as the binding agent, and the using amount of the binding agent accounts for 3% of the total mass of the powder. The ceramic prepared by the method has good sintering performance at 850-900 DEG C; the dielectric constant of the ceramic reaches 17-18, the quality factor QF value of the ceramic reaches up to 57000-83000GHz, and the temperature coefficient of resonance frequency of the ceramic is small; the low-temperature sintered vanadate microwave dielectric ceramic and an Ag electrode can be sintered together at low temperature, and therefore, the low-temperature sintered vanadate microwave dielectric ceramic has very great application value in industry.

Description

Can low-temperature sintering vanadate microwave dielectric ceramic BaZnV 2o 7and preparation method thereof

Technical field

The present invention relates to dielectric ceramic material, particularly relate to microwave dielectric ceramic material of the microwave devices such as medium substrate, resonator and the filter used in microwave frequency and preparation method thereof.

Background technology

Microwave dielectric ceramic refers to and is applied to microwave frequency band (mainly UHF, SHF frequency range) complete the pottery of one or more functions as dielectric material in circuit, resonator is widely used as in modern communication, filter, the components and parts such as dielectric substrate and medium wave circuit, it is the key foundation material of modern communication technology, at portable mobile phone, automobile telephone, cordless telephone, there is very important application the aspects such as telstar recipient and military radar, in the miniaturization of modern communication instrument, increasing effect is just being played in integrated process.

Be applied to the dielectric ceramic of microwave frequency band, the requirement of following dielectric property should be met: (1) seriation DIELECTRIC CONSTANT ε _rto adapt to the requirement of different frequency and different application occasion; (2) high quality factor q value or dielectric loss tan δ to reduce noise, General Requirements Qf>=3000GHz; (3) the temperature coefficient τ of resonance frequency _flittle of as far as possible to ensure the thermal stability that device has had, General Requirements-10/ DEG C≤τ _f≤+10ppm/ DEG C.From late 1930s, just someone attempts dielectric substance to be applied to microwave technology in the world.

According to relative dielectric constant ε _rsize from use frequency range different, usually the microwave-medium ceramics be developed and developing can be divided into 4 classes.

(1) ultralow dielectric microwave dielectric ceramic, main representative is Al ₂o ₃-TiO ₂, Y ₂baCuO ₅, MgAl ₂o ₄and Mg ₂siO ₄deng, its ε _r≤ 20, quality factor q × f>=50000GHz, τ _f≤ 10ppm/ DEG C.Be mainly used in microwave base plate and high-end microwave device.

(2) low ε _rwith the microwave dielectric ceramic of high q-factor, mainly BaO-MgO-Ta ₂o ₅, BaO-ZnO-Ta ₂o ₅or BaO-MgO-Nb ₂o ₅, BaO-ZnO-Nb ₂o ₅system or the hybrid system MWDC material between them.Its ε _r=25 ~ 30, Q=(1 ~ 2) × 10 ⁴(under f>=10GHz), τ _f≈ 0.Be mainly used in the microwave communication equipments such as the direct broadcasting satellite of f >=8GHz as dielectric resonance device.

(3) medium ε _rwith the microwave dielectric ceramic of Q value, mainly with BaTi ₄o ₉, Ba ₂ti ₉o ₂₀(Zr, Sn) TiO ₄deng the MWDC material for base, its ε _r=35 ~ 40, Q=(6 ~ 9) × 10 ³(under f=3 ~-4GHz), τ _f≤ 5ppm/ DEG C.Be mainly used in microwave military radar in 4 ~ 8GHz frequency range and communication system as dielectric resonance device.

(4) high ε _rand the microwave dielectric ceramic that Q value is lower, be mainly used in civilian mobile communcations system in 0.8 ~ 4GHz frequency range, this is also the emphasis of microwave dielectric ceramic research.Since the eighties, the people such as Kolar, Kato in succession find and have studied perovskite-like tungsten bronze type BaO-Ln ₂o ₃-TiO ₂series (Ln=La, Sm, Nd or Pr etc. are called for short BLT system), complex perovskite structure CaO-Li ₂o-Ln ₂o ₃-TiO ₂series, lead base series material, Ca _1-xln _2x/3tiO ₃be contour ε _rmicrowave dielectric ceramic, the wherein BaO-Nd of BLT system ₂o ₃-TiO ₂material dielectric constant reaches 90, lead base series (Pb, Ca) ZrO ₃dielectric constant reaches 105.

The sintering temperature of these material systems is generally higher than 1300 DEG C above, can not directly and the low-melting-point metal such as Ag and Cu burn formation multilayer ceramic capacitor altogether.In recent years, along with LTCC Technology (Low Temperature Co-fired Ceramics, the requirement of development LTCC) and the development of microwave multilayer device, researcher both domestic and external has carried out exploring widely and studying to some low fever's system materials, mainly adopt devitrified glass or glassceramic composites system, because low-melting glass has relatively high dielectric loss mutually, the existence of glassy phase substantially increases the dielectric loss of material.Therefore development is the emphasis of current research without the low fired microwave dielectric ceramic material of glassy phase.

Can in the process of low fired microwave dielectric ceramic materials in exploration and development of new, the material systems such as the Li based compound that intrinsic sintering temperature is low, Bi based compound, tungstates architecture compound and tellurate architecture compound get the attention and research, due to containing the compound such as Bi, Te and Mo easily and Ag electrode generation interfacial reaction and raw material TeO ₂poisonous the application of these Bi, Te and Mo sills is restricted, therefore can the high performance microwave media ceramic system of low fever still very limited, which greatly limits the development of low temperature co-fired technology and microwave multilayer device.

Summary of the invention

The object of this invention is to provide and a kind of there is low-loss and good thermal stability, vanadate microwave dielectric ceramic material that sintering temperature is low simultaneously and preparation method thereof.

The chemical composition of vanadate microwave dielectric ceramic material of the present invention is: BaZnV ₂o ₇.

Preparation method's concrete steps of described vanadate pottery are:

(1) be the BaCO of more than 99.9% by purity ₃, ZnO and V ₂o ₅starting powder press BaZnV ₂o ₇chemical formula weigh batching.

(2) step (1) raw material wet ball-milling is mixed 12 hours, solvent is distilled water, pre-burning 6 hours in 750 DEG C of air atmosphere after oven dry.

(3) in the powder that step (2) is obtained, binding agent is added and after granulation, more compressing, finally in 850 ~ 900 DEG C of air atmosphere, sinter 4 hours; Described binding agent adopts mass concentration to be the poly-vinyl alcohol solution of 5%, and dosage accounts for 3% of powder gross mass.

Pottery prepared by the present invention is good at 850-900 DEG C of sintering, its dielectric constant reaches 17 ~ 18, and quality factor q f value is up to 57000-83000GHz, and temperature coefficient of resonance frequency is little, and can be low temperature co-fired with Ag electrode, therefore industrially there is great using value.

Embodiment

Embodiment:

Table 1 shows 3 specific embodiments and microwave dielectric property thereof that form different sintering temperature of the present invention.Its preparation method is described above, carries out the evaluation of microwave dielectric property by cylindrical dielectric resonator method; Powder is mixed with the Ag powder accounting for powder quality 20%, compressing after, at 880 DEG C of sintering; X-ray diffraction material phase analysis and scanning electron microscopic observation all show BaZnV ₂o ₇chemical reaction is not there is not, i.e. BaZnV with Ag ₂o ₇can be low temperature co-fired with Ag electrode.

The present invention is never limited to above embodiment.Bound, the interval value of sintering temperature can realize the present invention, do not enumerate embodiment at this.

This pottery can be widely used in the manufacture of the microwave devices such as various medium substrate, resonator and filter, can meet the technology needs of the system such as mobile communication, satellite communication.

Table 1:

Claims (1)

1. vanadate is as can the application of low-temperature sintered microwave dielectric ceramic, it is characterized in that the chemical constitution formula of described vanadate is: BaZnV ₂o ₇;

Preparation method's concrete steps of described vanadate are:

(1) be the BaCO of more than 99.9% by purity ₃, ZnO and V ₂o ₅starting powder press BaZnV ₂o ₇chemical formula weigh batching;

(2) step (1) raw material wet ball-milling is mixed 12 hours, solvent is distilled water, pre-burning 6 hours in 750 DEG C of air atmosphere after oven dry;

(3) in the powder that step (2) is obtained, binding agent is added and after granulation, more compressing, finally in 850 ~ 900 DEG C of air atmosphere, sinter 4 hours; Described binding agent adopts mass concentration to be the poly-vinyl alcohol solution of 5%, and dosage accounts for 3% of powder gross mass.