CN103539449A

CN103539449A - Low temperature sinterable microwave dielectric ceramic BiNbW2O10 and its preparation method

Info

Publication number: CN103539449A
Application number: CN201310459121.8A
Authority: CN
Inventors: 方亮; 蒋雪雯; 郭欢欢
Original assignee: Guilin University of Technology
Current assignee: Li Guofu
Priority date: 2013-10-07
Filing date: 2013-10-07
Publication date: 2014-01-29
Anticipated expiration: 2033-10-07
Also published as: CN103539449B

Abstract

本发明公开了一种可低温烧结的微波介电陶瓷BiNbW₂O₁₀及其制备方法。可低温烧结的微波介电陶瓷的组成为BiNbW₂O₁₀。（1）将纯度为99.9%以上的Bi₂O₃、Nb₂O₅和WO₃的原始粉末按BiNbW₂O₁₀化学式称量配料。（2）将步骤（1）原料混合湿式球磨12小时，溶剂为蒸馏水，烘干后在850℃大气气氛中预烧6小时。（3）在步骤（2）制得的粉末中添加粘结剂并造粒后，再压制成型，最后在900~930℃大气气氛中烧结4小时；所述的粘结剂采用质量浓度为5%的聚乙烯醇溶液，剂量占粉末总质量的3%。本发明制备的陶瓷在900~930℃烧结良好，其介电常数达到17～18，品质因数Qf值高达86000-98000GHz，谐振频率温度系数小，可以与Ag电极低温共烧，在工业上有着极大的应用价值。The invention discloses a low-temperature sinterable microwave dielectric ceramic BiNbW ₂ O ₁₀ and a preparation method thereof. The composition of the low-temperature sinterable microwave dielectric ceramic is BiNbW ₂ O ₁₀ . (1) The original powders of Bi ₂ O ₃ , Nb ₂ O ₅ and WO ₃ with a purity of more than 99.9% are weighed and compounded according to the chemical formula of BiNbW ₂ O ₁₀ . (2) The raw materials in step (1) were mixed and wet-type ball milled for 12 hours, the solvent was distilled water, and after drying, pre-calcined in the atmosphere at 850°C for 6 hours. (3) Add a binder to the powder prepared in step (2) and granulate it, then press it into shape, and finally sinter it in the atmosphere at 900-930°C for 4 hours; the binder is used at a mass concentration of 5 % polyvinyl alcohol solution, the dosage accounts for 3% of the total mass of the powder. The ceramic prepared by the invention is well sintered at 900-930°C, its dielectric constant reaches 17-18, its quality factor Qf value is as high as 86000-98000 GHz, and its resonant frequency temperature coefficient is small. Great application value.

Description

Low temperature sintering microwave dielectric ceramic BiNbW 2o 10and 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 and is applied in microwave frequency band (being mainly UHF, SHF frequency range) circuit as dielectric material and completes the pottery of one or more functions, in modern communication, be widely used as the 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, at aspects such as portable mobile phone, automobile telephone, cordless telephone, telestar susceptor and military radars, there is very important application, in the miniaturization of modern communication instrument, integrated process, just bringing into play increasing effect.

Be applied to the dielectric ceramic of microwave frequency band, should meet the requirement of following dielectric characteristics: (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 are to reduce noise, general requirement Qf>=3000 GHz; (3) the temperature factor τ of resonant frequency _?the as far as possible little thermostability to guarantee that device has had, general requirement-10/ ℃≤τ _?≤+10 ppm/ ℃.From late 1930s, just someone attempts dielectric substance to be applied to microwave technology in the world.

According to relative permittivity ε _rsize from use the different of frequency range, conventionally the microwave dielectric ceramic being developed He 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 _?≤ 10 ppm/ ° C.Be mainly used in microwave base plate and high-end microwave device.

(2) low ε _rwith the microwave dielectric ceramic of high Q value, be mainly 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 the GHz of f>=10), τ _?≈ 0.Be mainly used in the microwave communication equipments such as direct broadcasting satellite of f >=8 GHz as dielectric resonance device.

(3) medium ε _rwith the microwave dielectric ceramic of Q value, be mainly 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(under f=3～-4GHz), τ _?≤ 5 ppm/ ° C.Be mainly used in microwave military radar in 4～8 GHz range of frequency and communication system as 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, this is also the emphasis of microwave dielectric ceramic research.Since the eighties, the 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.

The sintering temperature of these material systems is generally higher than 1300 ° of C above, can not be directly and the low melting point metal such as Ag and Cu burn altogether formation laminated ceramic capacitor.In recent years, along with LTCC Technology (Low Temperature Co-fired Ceramics, the requirement of development LTCC) and the development of microwave multilayer device, researchist both domestic and external has carried out exploring widely and studying to some low fever's system materials, mainly to adopt devitrified glass or glass-ceramic composite system, because low melting glass has relatively high dielectric loss mutually, the existence of glassy phase has improved the dielectric loss of material greatly.Therefore development is the emphasis of current research without the low temperature sintering microwave dielectric ceramic of glassy phase.We are to consisting of BiNbW ₂o ₁₀tungstate ceramics carried out sintering characteristic and Study on microwave dielectric property, found that BiNbW ₂o ₁₀pottery but has excellent comprehensive microwave dielectric property while sintering temperature lower than 930 °c, can be widely used in the manufacture of the microwave devices such as various resonators and wave filter, can meet the needs of low temperature co-fired technology and microwave multilayer device.

Summary of the invention

The object of this invention is to provide a kind of have low-loss and good thermostability, sintering temperature is low, microwave dielectric ceramic that can be low temperature co-fired with Ag and preparation method thereof.

The chemical constitution of the low temperature sintering microwave dielectric ceramic the present invention relates to is: BiNbW ₂o ₁₀.

Preparation method's concrete steps of described low temperature sintering microwave dielectric ceramic are:

(1) by purity, be more than 99.9% Bi ₂o ₃, Nb ₂o ₅and WO ₃starting powder press BiNbW ₂o ₁₀chemical formula weigh batching.

(2) by step (1) raw material mixing wet ball-milling 12 hours, solvent was distilled water, pre-burning 6 hours in 850 ℃ of air atmosphere after oven dry.

(3) in the powder making in step (2), add after binding agent granulation, then compression moulding, finally sintering 4 hours in 900 ~ 930 ℃ of air atmosphere; Described binding agent adopts the polyvinyl alcohol solution that mass concentration is 5%, and dosage accounts for 3% of powder total mass.

Pottery prepared by the present invention is good at 900-930 ℃ of sintering, and its specific inductivity reaches 17～18, and quality factor q f value is up to 86000-98000GHz, and temperature coefficient of resonance frequency is little, can be low temperature co-fired with Ag electrode, industrial, there is a great using value.

Embodiment

Embodiment:

Table 1 shows 4 specific embodiments and the microwave dielectric property thereof that forms different sintering temperatures of the present invention.Its preparation method as mentioned above, carries out the evaluation of microwave dielectric property by cylindrical dielectric resonator method.By BiNbW ₂o ₁₀powder mixes with the Ag powder that accounts for powder quality 20%, after compression moulding, at 930 ℃, sintering is 4 hours; X ray diffraction material phase analysis and scanning electron microscopic observation all show BiNbW ₂o ₁₀there is not chemical reaction, i.e. BiNbW with Ag ₂o ₁₀can be low temperature co-fired with Ag electrode.

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

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

Table 1:

Claims

1. A low-temperature sinterable microwave dielectric ceramic, characterized in that the chemical composition formula of the low-temperature sinterable microwave dielectric ceramic is: BiNbW ₂ O ₁₀ ;

The specific steps of the preparation method of the low-temperature sinterable microwave dielectric ceramic are:

(1) Weigh the original powders of Bi ₂ O ₃ , Nb ₂ O ₅ and WO ₃ with a purity of more than 99.9% according to the chemical formula of BiNbW ₂ O ₁₀ ;

(2) Mix the raw materials of step (1) by wet ball milling for 12 hours, the solvent is distilled water, and after drying, pre-fire in the atmosphere at 850°C for 6 hours;

(3) Add a binder to the powder prepared in step (2) and granulate it, then press it into shape, and finally sinter it in the atmosphere at 900-930°C for 4 hours; the binder is used at a mass concentration of 5 % polyvinyl alcohol solution, the dosage accounts for 3% of the total mass of the powder.