CN102285796A - Ytterbia-added anti-ferroelectric lead zirconate-titanate dielectric ceramic - Google Patents

Abstract

The invention discloses ytterbia-added anti-ferroelectric lead zirconate-titanate dielectric ceramic which is a powder body with the molar-percentage content of raw-material components being Pb(1-x)Yb(x)(Zr0.95Ti0.05)O3, wherein x=0.0067-0.0267. The invention provides the dielectric ceramic with stable dielectric performance and good comprehensive performance by adopting a traditional solid-phase synthesizing preparation method, and the dielectric ceramic has the advantages of simple component, simple process step, easiness in operation, good repeatability and high finished-product rate. The dielectric ceramic is mainly applied to temperature-compensating capacitors, thermally-stable type capacitors, microwave dielectric ceramic and the like.

Description

Add the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of ytterbium oxide

Technical field

The invention relates to the composition is the ceramic composition of feature, relates in particular to antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics.

Background technology

Dielectric substance is meant that resistivity is greater than 10 ¹⁰The material of Ω cm, with respect to metallic substance and semiconductor material and distinguish, dielectric medium in electric field, do not stablize conduction current by and in the induced mode corresponding disturbance material is made in the outfield.The kind of dielectric substance is a lot, comprises insulating material, capacitor material and piezoelectric etc.Dielectric feature is to transmit, store or write down the role and influence of electricity in the electropolarization mode that positive and negative electric charge center of gravity does not overlap, but what wherein play a major role is bound charge.It is mainly used and comprises thermo-compensation capacitor, thermostable type capacitor ceramic material and microwave dielectric ceramic etc.

Along with the development of the miniaturized intelligentization of electronic impulse technology, High-Voltage Technology and electronic devices and components, require dielectric substance to develop in recent years towards large vol, low-loss, high resistance, high withstand voltage direction.

C Kittle has described the basic structural feature of antiferroelectric crystal with the Shuangzi crystal model, the same with ferroelectric crystal, there is the ion displacement spontaneous polarization in the antiferroelectric crystal sublattice equally, but the direction of adjacent sublattice intermediate ion spontaneous polarization is opposite, so macroscopical spontaneous polarization strength of antiferroelectric crystal is zero.Ferroelectrics is more superior energy storage material, does not have residual polarization, and the energy storage capacitor made from it has the high and energy storage of energy storage density and discharges sufficient advantage.In addition, antiferroelectric materials has the characteristic of high dielectric constant and the further increase of specific inductivity under certain high pressure, and the loss of antiferroelectric materials is little, and resistivity is bigger, breaking down field strength is also very high, so the antiferroelectric ceramic dielectric material has wide application space.

Along with the hyundai electronics fast development of information technology, exploitation and exploration for the excellent performance dielectric substance have become the hot issue that various countries are studied, at present, mainly adopt 2 kinds of methods aspect improvement in performance: a kind of is doping vario-property, and certain modification ion promptly mixes; Another kind is to improve preparation technology.

Because unadulterated antiferroelectric Pb (Zr _0.95Ti _0.05) O ₃Dielectric substance is when Curie temperature is above, and its dielectric properties change greatly, can not be stabilized in certain temperature range, so, by adding Yb ₂O ₃, form Pb _(1-x)Yb _(x)(Zr _0.95Ti _0.05) O ₃Multi-element compounds changes Yb again ₂O ₃Content, seek the good dielectric substance of a kind of dielectric properties.

Summary of the invention

The objective of the invention is, provide a kind of dielectric properties better dielectric ceramics on the basis of existing technology, make it meet large vol, low-loss, high resistance, high withstand voltage developing direction.

The present invention is achieved by the following technical programs:

Add the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of ytterbium oxide, its feed composition and mole percent level thereof are Pb _(1-x)Yb _(x)(Zr _0.95Ti _0.05) O ₃, x=0.0067～0.0267 wherein.

Described raw material is Pb ₃O ₄, ZrO ₂, TiO ₂And Yb ₂O ₃

Described dielectric ceramics is single perovskite structure.

Described dielectric ceramics is incubated 2h in 1210 ℃～1290 ℃ sintering, and heat-up rate is 6 ℃/minute.

The preparation method of described dielectric ceramics adopts traditional solid phase synthesis process.

Described dielectric ceramics relative permittivity in reaching 200 ℃ temperature range is stablized constant, has excellent temperature stability.

The invention has the beneficial effects as follows, provide a kind of dielectric properties stable, the good antiferroelectric PZT dielectric ceramics of over-all properties.The present invention adopts the method for traditional solid phase synthesis, and (PZT) is matrix with antiferroelectric Pb-based lanthanumdoped zirconate titanates, is that doping agent has obtained zirconium metatitanic acid ytterbium lead (PYZT) with Yb.Obtained a kind ofly having the dielectric ceramics of excellent temperature stability reaching 200 ℃ temperature range relative permittivity about 7000, its resistivity reaches 710 ¹³Ω cm, the super 10KV/mm of breaking down field strength.Composition of the present invention and processing step are simple, easy handling, good reproducibility, yield rate height.

Description of drawings

Fig. 1 is the X ray collection of illustrative plates and the standard diagram contrast mutually of antiferroelectric quadrature of the sample of the embodiment of the invention 3;

Fig. 2 is the scanning electronic microscope SEM picture of the embodiment of the invention 3;

Fig. 3 is the dielectric thermogram of the PYZT system of the embodiment of the invention 1,2,3,4, and is that 95/5 PZT is a reference with Zr and Ti proportioning.

Embodiment

The present invention adopts commercially available chemical pure raw material (purity 〉=99%), is Pb ₃O ₄, ZrO ₂, TiO ₂And Yb ₂O ₃

The present invention adopts the method for traditional solid phase synthesis, and concrete preparation process is:

(1) batching is synthetic

Press Pb _(1-x)Yb _(x)(Zr _0.95Ti _0.05) O ₃Stoichiometric ratio (x=0.006 in the formula～0.03) take by weighing raw material Pb ₃O ₄, ZrO ₂, TiO ₂And Yb ₂O ₃, mixing, in the nylon jar of packing into, ball-milling medium is water and agate ball, ball: material: the weight ratio of water is 2: 1: 0.6, and ball milling 4h, rotational speed of ball-mill are 750 rev/mins, and compound is put into 80 ℃ of oven dry of baking oven, puts into mortar again and grinds, and crosses 80 mesh sieves;

(2) pre-burning

Powder after grinding sieved is put into crucible, with the compacting of agate rod, adds a cover, and sealing, 900 ℃ of insulation 2h naturally cool to room temperature in retort furnace, come out of the stove;

(3) secondary ball milling

The powder of oven dry in the step (2) is ground in mortar, cross 80 mesh sieves, the ball grinder of packing into, ball: material: the weight ratio of water is 2: 1: 0.6, and ball milling 4h, rotational speed of ball-mill are 750 rev/mins, and powder is put into 80 ℃ of oven dry of baking oven;

(4) granulation

Powder porphyrize in mortar with step (3) oven dry sieves, and the adding weight concentration is 5%～10% polyvinyl alcohol (PVA), fully stir, sieve, powder is put into the stainless steel mould that diameter is 35mm, depress to cylindric blank at 100～120Mpa pressure.

(5) moulding

Powder after the granulation is left standstill 24h, again powder is put into the stainless steel mould that diameter is 12mm, depress to cylindric blank at 200～250Mpa pressure;

(6) binder removal

Blank is put into retort furnace, and 400 ℃ of insulation 1h carry out organism and get rid of;

(7) sintering

The binder removal blank is put into crucible, seal, do to bury with similar powder and expect to bury burning, heat-up rate is 6 ℃/minute, at 1210 ℃～1290 ℃ insulation 2h, naturally cools to room temperature with stove;

(8) burn electrode

The ceramic plate polishing that sinters is thick to 0.9～1.1mm, dry naturally, lower surface applies the silver slurry thereon, places 735 ℃ of insulations of stove 10min, naturally cools to room temperature;

(9) test dielectric properties.

Specific embodiment sees table 1 for details.

Press Pb _(1-x)Yb _(x)(Zr _0.95Ti _0.05) O ₃Stoichiometric ratio (x=0.0067 in the formula～0.0267) take by weighing raw material Pb ₃O ₄, ZrO ₂, TiO ₂And Yb ₂O ₃

Means of testing is: use the WAYNEKERR4225 type LCR automatic measuring instrument of Tianjin City, China wireless six factories, at room temperature measure the loss tangent tan δ and the capacitor C of sample, survey frequency is 1kHz, relative permittivity ε _rValue is calculated by following formula:

${\mathrm{\ϵ}}_r=\frac{{\mathrm{\ϵ}}_{33}^T}{{\mathrm{\ϵ}}_0}=\frac{4C\×h}{{\mathrm{\ϵ}}_0\×\mathrm{\π}{D}^2}$

In the formula: ε ₀-permittivity of vacuum, its value are 8.854 * 10 ^-12F/m; C-electric capacity, unit are the F:h-sample thickness, the m of unit; π-pi; Here get 3.1416; The D-specimen finish, the m of unit.

(Tokyo.TOA.Electronics Ltd.Japan), directly measures the insulation resistance of sample to adopt SM-5E type megohmmeter.Test voltage is direct current 500V, adds test voltage reading after a minute.

At room temperature, directly insert the breaking down field strength of direct supply test sample.Direct supply adopts the powerstat of magnificent prestige electrical equipment group company, and sample is immersed in the silicone oil.The maximum output voltage of this transformer is 12.6KV.

Table 1

The dielectric properties test result of the foregoing description sees table 2 for details:

Table 2

By performance shown in Figure 1 as can be known, gains process and the standard spectrogram contrast mutually of antiferroelectric quadrature mutually behind the interpolation Yb, both are identical substantially, do not have tangible further feature peak, are antiferroelectric quadrature phase so can infer the principal crystalline phase of sample.At least there is not the obvious characteristics peak to show the existence of other phase.The SEM picture of Fig. 2 shows, the density height of pottery, and pore is few, and institute is so that volume specific resistance and disruptive strength are all higher.By the dielectric temperature collection of illustrative plates of Fig. 3 as can be known, the adding of Yb has reduced the Curie temperature of system, but Curie temperature changes with the content of Yb hardly.Relative permittivity sharply descends after surpassing Curie temperature, and near 260 ℃, along with temperature raises, relative permittivity no longer includes significant variation, fluctuates in a small range, has reasonable temperature stability.And we see, when Yb content is that its specific inductivity of sample of 2.67mol% is stabilized in about 7000, institute's value is higher, compares with niobium, the adulterated antiferroelectric system of magnesium, though the adding of Yb has reduced ceramic specific inductivity, specific inductivity has obtained better temperature stability.So being its antiferroelectric ceramics of forming the place of sample of 2.67mol%, Yb content is fit to very much as dielectric ceramics.

Claims (6)

1. antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics that adds ytterbium oxide, its feed composition and mole percent level thereof are Pb _(1-x)Yb _(x)(Zr _0.95Ti _0.05) O ₃, x=0.0067～0.0267 wherein.

2. according to the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of the interpolation ytterbium oxide of claim 1, it is characterized in that described raw material is Pb ₃O ₄, ZrO ₂, TiO ₂And Yb ₂O ₃

3. according to the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of the interpolation ytterbium oxide of claim 1, it is characterized in that described dielectric ceramics is single perovskite structure.

4. according to the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of the interpolation ytterbium oxide of claim 1, it is characterized in that described dielectric ceramics is in 1210 ℃～1290 ℃ sintering, insulation 2h, heat-up rate is 6 ℃/minute.

5. according to the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of the interpolation ytterbium oxide of claim 1, it is characterized in that the preparation method of described dielectric ceramics adopts traditional solid phase synthesis process.

6. according to the antiferroelectric Pb-based lanthanumdoped zirconate titanates dielectric ceramics of the interpolation ytterbium oxide of claim 1, it is characterized in that described dielectric ceramics relative permittivity in reaching 200 ℃ temperature range is stablized constant, has excellent temperature stability.

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