CN103332932A

CN103332932A - Low-temperature sintered vanadate microwave dielectric ceramic BaZnV2O7 and preparation method thereof

Info

Publication number: CN103332932A
Application number: CN2013102524399A
Authority: CN
Inventors: 方亮; 唐莹; 韦珍海
Original assignee: Guilin University of Technology
Current assignee: Suzhou Hongwu Technology Intermediary Service Co.,Ltd.
Priority date: 2013-06-24
Filing date: 2013-06-24
Publication date: 2013-10-02
Anticipated expiration: 2033-06-24
Also published as: CN103332932B

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

But 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 wave filter that use in microwave frequency and preparation method thereof.

Background technology

Microwave dielectric ceramic refers to be applied in microwave frequency band (mainly being UHF, the SHF frequency range) circuit as dielectric material and finishes the pottery of one or more functions, in modern communication, be widely used as components and parts such as resonator, wave filter, dielectric substrate and medium guided wave loop, it is the key foundation material of modern communication technology, very important use has been arranged at aspects such as portable mobile phone, automobile telephone, cordless telephone, telestar susceptor and military radars, in the miniaturization of modern communication instrument, integrated process, just brought into play increasing effect.

Be applied to the dielectric ceramic of microwave frequency band, should satisfy the requirement of following dielectric characteristics: (1) seriation DIELECTRIC CONSTANT _rTo adapt to the requirement of different frequency and different application occasion; (2) high quality factor q value or dielectric loss tan δ are to reduce noise, general requirement Qf 〉=3000GHz; (3) the temperature factor τ of resonant frequency _fAs far as possible little of guaranteeing that device has good thermostability, general requirement-10/ ℃≤τ _f≤+10ppm/ ℃.In the world from late 1930s just the someone attempt dielectric substance is applied to microwave technology.

According to relative permittivity ε _rSize with use the different of frequency range, the microwave-medium ceramics that is developed He developing can be divided into 4 classes usually.

(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/ ℃.Be mainly used in microwave base plate and high-end microwave device.

(2) low ε _rWith the microwave dielectric ceramic of high Q value, mainly be BaO-MgO-Ta ₂O ₅, BaO-ZnO-Ta ₂O ₅Or BaO-MgO-Nb ₂O ₅, BaO-ZnO-Nb ₂O ₅System or the composite 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 direct broadcasting satellite of f 〉=8GHz as the dielectric resonance device.

(3) medium ε _rWith the microwave dielectric ceramic of Q value, mainly be with BaTi ₄O ₉, Ba ₂Ti ₉O ₂₀(Zr, Sn) TiO ₄Deng the MWDC material that is base, its ε _r=35～40, Q=(6～9) * 10 ³(f=3～-4GHz under), τ _f≤ 5ppm/ ℃.Be mainly used in the interior microwave military radar of 4～8GHz range of frequency and the communication system as the dielectric resonance device.

(4) high ε _rAnd the lower microwave dielectric ceramic of Q value is mainly used in civilian mobile communcations system in 0.8～4GHz range of frequency, and this also is the emphasis of microwave dielectric ceramic research.Since the eighties, people such as Kolar, Kato find and have studied perovskite-like tungsten bronze type BaO-Ln in succession 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 ₃Specific inductivity reaches 105.

More than the sintering temperature of these material systems generally be higher than 1300 ℃, can not be directly and low melting point metals such as Ag and Cu burn the formation laminated 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, domestic and international research personnel have carried out exploring widely and studying to some low fever's system materials, mainly be to adopt devitrified glass or glass-ceramic composite system, because low melting glass has higher relatively dielectric loss mutually, the existence of glassy phase has improved the dielectric loss of material greatly.Therefore the low fired microwave dielectric ceramic material of the no glassy phase of development is the emphasis of current research.

Can hang down in the process of fired microwave dielectric ceramic materials in exploration and development of new, material systems such as the Li based compound that intrinsic sintering temperature is low, Bi based compound, tungstate architecture compound and tellurate architecture compound have obtained extensive concern and research, owing to contain compounds such as Bi, Te and Mo easy and Ag electrode generation surface reaction and raw material TeO ₂Poisonously make the application of these Bi, Te and Mo sill be restricted, but therefore low fever's high performance microwave media ceramic system is still very limited, this has limited the development of low temperature co-fired technology and microwave multilayer device to a great extent.

Summary of the invention

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

The chemical constitution 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) with purity is BaCO more than 99.9% ₃, ZnO and V ₂O ₅Starting powder press BaZnV ₂O ₇The chemical formula weigh batching.

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

(3) in the powder that step (2) makes, add binding agent and granulation after, compression moulding again, sintering 4 hours in 850～900 ℃ of air atmosphere at last; Described binding agent employing mass concentration is 5% polyvinyl alcohol solution, and dosage accounts for 3% of powder total mass.

The pottery of the present invention's preparation is good at 850-900 ℃ of sintering, its specific inductivity 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 the Ag electrode, therefore industrial great using value arranged.

Embodiment

Embodiment:

Table 1 shows 3 specific embodiments and the microwave dielectric property thereof that constitutes different sintering temperatures of the present invention.Its preparation method carries out the evaluation of microwave dielectric property as mentioned above with the cylindrical dielectric resonator method; With powder mix with the Ag powder that accounts for powder quality 20%, after the compression moulding, at 880 ℃ of sintering; X-ray diffraction material phase analysis and scanning electron microscopic observation all show BaZnV ₂O ₇Chemical reaction, i.e. BaZnV do not take place with Ag ₂O ₇Can be low temperature co-fired with the Ag electrode.

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

This pottery can be widely used in the manufacturing of microwave devices such as various medium substrates, resonator and wave filter, can satisfy the Technology Need of systems such as mobile communication, satellite communications.

Table 1:

Claims

1. but the application of a vanadate conduct low-temperature sintered microwave dielectric ceramic 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) with purity is BaCO more than 99.9% ₃, ZnO and V ₂O ₅Starting powder press BaZnV ₂O ₇The chemical formula weigh batching;

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

(3) in the powder that step (2) makes, add binding agent and granulation after, compression moulding again, sintering 4 hours in 850 ~ 900 ℃ of air atmosphere at last; Described binding agent employing mass concentration is 5% polyvinyl alcohol solution, and dosage accounts for 3% of powder total mass.