CN105130424A - BiYO3-doped BaTiO3-based relaxor ferroelectric and preparation method therefor - Google Patents

Abstract

The invention discloses a BiYO3-doped BaTiO3-based relaxor ferroelectric and a preparation method therefor. The preparation method comprises: firstly preparing pure phase BaTiO3 powder and pure phase BiYO3 powder; then mixing the BaTiO3 powder and the BiYO3 powder according to BaTiO3+xmol%BiYO3 and mixing with zirconium balls and deionized water, and sequentially ball-milling, drying, prilling and screening the mixture to form a granulated material, wherein x is 2-30, and xmol% represents mol percentage; preparing a test sample by the granulated material at a pressure of 120MPa and then carrying out primary sintering; and polishing and cleaning the primarily sintered test sample, and uniformly coating silver electrode slurry on the front and back faces of the test sample for secondary sintering so as to obtain the BiYO3-doped BaTiO3-based relaxor ferroelectric. The lead-free dielectric material prepared by the preparation method disclosed by the invention meets the most important two characteristics: a diffused phase transition characteristic and a frequency dispersion characteristic in the aspect of dielectric property of the relaxor ferroelectric. The relaxor ferroelectric is simple in preparation method, low in cost and environmental-friendly.

Description

A kind of BiYO 3doping BaTiO 3base relaxation ferroelectric and preparation method thereof

Technical field

The present invention relates to ceramic dielectric material field, be specifically related to a kind of BiYO ₃doping BaTiO ₃base relaxation ferroelectric and preparation method thereof.

Background technology

Ferroelectrics is the special dielectric medium of a class, and the feature of its specific inductivity is that numerical value is large, non-linear effect strong, has significant temperature dependency and frequency dependence.But due to its structure, a lot of ferroelectric Curie temperature is higher, makes its specific inductivity just have maximum value when comparatively high temps, and at room temperature specific inductivity, much smaller than the specific inductivity of Curie temperature, thus greatly limit its use properties.Therefore must change ferroelectric structure makes the temperature range that its Curie temperature reduces, specific inductivity increases, be suitable for broaden, and thus proposes the concept of relaxation ferroelectric (RFE).Perovskite structure ferroelectrics studies a class ferroelectrics the most widely at present, and its skeleton symbol is ABO ₃.Because the distinctive geometry free-running property of perovskite structure can hold the dopant ion of different size, so different A position or B position and A position and B position recombination energy access much complex perovskite structure sosoloid and compound, this compounds becomes the object that many scholars competitively study naturally.Wherein, the former Russian scholar etc. synthesize the New Wave that the lead magnoniobate with Relaxivity has started relaxation ferroelectric research first.Be different from independent relaxation phenomena and ferroelectricity, traditional sense is thought that both break mutual unrelated saying by unique relaxation behavior, and both perfect adaptations are called Relaxation Ferroelectrics by people together.Compared with common ferroelectrics, topmost two the feature Diffuse phase transition in relaxation ferroelectric dielectric properties aspect and frequency dispersion.

At present, many scholars have been had to BaTiO ₃(BT) the unleaded relaxation ferroelectric ceramic material of base conducts extensive research.The working range of current BT material is narrow, is not suitable for industrial demand, and therefore, development relaxation ferroelectric is very important.Henan ferroelectrics not only has high dielectric properties, relatively low firing temperature, also has the low temperature coefficient of capacitance caused by " Diffuse phase transition ".No matter be therefore preparation technology aspect or aspect with low cost, be all considered to the only choosing of alternative laminated ceramic capacitor.

Summary of the invention

The object of the present invention is to provide a kind of BiYO ₃doping BaTiO ₃base relaxation ferroelectric and preparation method thereof, to overcome the defect that above-mentioned prior art exists, preparation technology of the present invention is simple, and the cost of material is low, and obtained relaxation ferroelectric has higher specific inductivity, low dielectric loss, likely becomes alternative unleaded BaTiO ₃the important candidate material that base relaxation type stupalith is double excellent technically and economically.

For achieving the above object, the present invention adopts following technical scheme:

A kind of BiYO ₃doping BaTiO ₃base relaxation ferroelectric, it is prepared material and comprises BaTiO ₃+ xmol%BiYO ₃, wherein x=2 ~ 30, xmol% represents molar percentage.

A kind of BiYO ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, comprises the following steps:

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, in 1120 ~ 1150 DEG C of insulations 2 ~ 3 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, in 920 ~ 940 DEG C of insulations 2 ~ 3 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ xmol%BiYO ₃form mixture C after mixing, wherein x=2 ~ 30, xmol% represents molar percentage, by mixture C and zirconium ballstone and deionized water, is carry out ball milling, oven dry, granulation successively after 1:1:1 mixing, sieve, forms granulation material according to mass ratio;

Step 4: step 3 gained granulation material is made sample under the pressure of 110 ~ 120MPa, then carries out once sintered;

Step 5: in polishing, cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, carry out double sintering, obtain BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Further, in step 3, mixture C mixes with zirconium ballstone and deionized water, ball milling, formed to dry after oven dry and expect, by mass concentration be 4 ~ 6% tackiness agent be added into dry material in carry out granulation, tackiness agent accounts for dries 8 ~ 10% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material.

Further, described tackiness agent is polyvinyl alcohol water solution.

Further, in step 3, Ball-milling Time is 4 ~ 6 hours.

Further, in step 4, once sintered condition is: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, be incubated 3 hours, afterwards, after being cooled to 500 DEG C, cool to room temperature with the furnace with 5 DEG C/min when being warming up to 1250 ~ 1300 DEG C with 5 DEG C/min.

Further, in step 5, the condition of double sintering is: temperature is 600 ~ 620 DEG C, and the time is 20 ~ 30 minutes.

A kind of BiYO ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, comprises the following steps:

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1150 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 940 DEG C of insulations 2 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 30mol%BiYO ₃mixed in molar ratio after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 4h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 6% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 10% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of double sinterings 20 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Compared with prior art, the present invention has following useful technique effect:

Relaxor Ferroelectric Materials of the present invention, (during x=2, specific inductivity is 7737 to have higher specific inductivity, during x=30, specific inductivity is 425), large, the good temperature stability of low dielectric loss (tan δ≤0.01), body resistivity, likely becoming alternative lead base stupalith becomes laminated ceramic capacitor and to hold concurrently technically and economically excellent important candidate material.

The present invention is by BiYO ₃be doped to BaTiO ₃the inside, Bi replaces BaTiO ₃a position, Y replaces BaTiO ₃b position, by doping realize BaTiO ₃the broadening at Curie peak, realize relaxation diffusing phenomenon, thus reach the requirement of Relaxor Ferroelectric Materials.The inventive method adopts conventional solid-state method preparation, technical maturity, is applicable to industrialization and produces, adopt BiYO ₃adulterate, realize the Diffuse phase transition that valence compensation is conducive to realizing barium titanate ceramics, not only preparation technology is simple for the Relaxor Ferroelectric Materials prepared of the inventive method, the cost of material is low, and have compared with high specific inductivity, low dielectric loss, body resistivity is large, temperature stability good, laminated ceramic capacitor is become to alternative lead base stupalith and to hold concurrently technically and economically excellent important candidate material.The present invention passes through BiYO ₃doping BaTiO ₃base pottery, obtain Relaxation Ferroelectrics, there is wide operation temperature area, there is frequency dispersion and Diffuse phase transition characteristic that relaxation ferroelectric possesses, specific inductivity is high, dielectric loss is less, can be applied in the preparation process of laminated ceramic capacitor, is applicable in ask for something much higher layer ceramic condenser field.

Accompanying drawing explanation

Fig. 1 is the rational curve of the dielectric constant with temperature change of the sample that blank case study on implementation obtains;

Fig. 2 is the rational curve of the dielectric constant with temperature change of the sample that embodiment 1 obtains;

Fig. 3 is the rational curve of the dielectric constant with temperature change of the sample that embodiment 2 obtains;

Fig. 4 is the rational curve of the dielectric constant with temperature change of the sample that embodiment 3 obtains;

Fig. 5 is the rational curve of the dielectric constant with temperature change of the sample that embodiment 4 obtains;

Fig. 6 is the rational curve of the dielectric constant with temperature change of the sample that embodiment 5 obtains;

Fig. 7 is the lnf ~ T of the sample that blank Example and embodiment 1-2 obtain _mcurve;

Fig. 8 is the lnf ~ T of the sample that embodiment 3-5 obtains _mcurve;

Fig. 9 is ln (1/ ε-1/ ε of the sample that blank Example and embodiment 1-2 obtain _m) ~ ln (T-T _m) curve;

Figure 10 is ln (1/ ε-1/ ε of the sample that embodiment 3-5 obtains _m) ~ ln (T-T _m) curve.

Embodiment

Below embodiments of the present invention are described in further detail:

A kind of BiYO ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, comprises the following steps:

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1120 ~ 1150 DEG C of insulations 2 ~ 3 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 920 ~ 940 DEG C of insulations 2 ~ 3 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ xmol%BiYO ₃mixture C is formed, i.e. BaTiO after mixing ₃molar percentage be (100-x) mol%, BiYO ₃molar percentage be xmol%, BaTiO ₃mole number and BiYO ₃mole number sum equal the mole number of mixture C, wherein x=2 ~ 30, xmol% represents molar percentage, by mixture C and zirconium ballstone and deionized water, according to mass ratio be 1:1:1 mixing after ball milling 4 ~ 6h, then dry formed dry material, by mass concentration be 4 ~ 6% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution account for dry material quality 8 ~ 10%, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 110 ~ 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1250 ~ 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 ~ 620 DEG C of double sinterings 20 ~ 30 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Below in conjunction with embodiment, the present invention is described in further detail:

Blank Example

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace respectively at 1120 ~ 1150 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: the BaTiO that step one is obtained ₃powder and zirconium ballstone and deionized water, be carry out ball milling, oven dry, granulation successively after 1:1:1 mixing, sieve according to mass ratio, form granulation material;

Step 3: step 2 gained granulation material is made sample under the pressure of 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered, 500 DEG C of insulation 60min are warming up to 2 DEG C/min, 3 hours are incubated when being warming up to 1250 ~ 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, room temperature is cooled to the furnace;

Step 4: polishing, in cleaning step three after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of double sinterings 20 minutes, obtains blank sample.

Embodiment 1

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1120 DEG C of insulations 3 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 920 DEG C of insulations 3 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 2mol%BiYO ₃mol ratio mixing after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 6h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 4% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 8% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 110MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1250 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 620 DEG C of double sinterings 30 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Embodiment 2

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1130 DEG C of insulations 2.5 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 930 DEG C of insulations 2.5 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 4mol%BiYO ₃mixed in molar ratio after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 5h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 5% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 9% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 115MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1280 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 610 DEG C of double sinterings 25 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Embodiment 3

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1150 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 940 DEG C of insulations 2 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 10mol%BiYO ₃mixed in molar ratio after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 4h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 6% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 10% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of double sinterings 20 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Embodiment 4

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1120 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 920 DEG C of insulations 3 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 20mol%BiYO ₃mol ratio mixing after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 4h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 4% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 8% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1250 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of double sinterings 30 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

Embodiment 5

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1130 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 930 DEG C of insulations 2 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 30mol%BiYO ₃mixed in molar ratio after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 6h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 5% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 9% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 110MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1280 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 610 DEG C of double sinterings 20 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

As shown in Figures 1 to 10, dielectric properties test shows: blank Example and the ceramic medium material prepared by embodiment 1 to embodiment 5 all meet Relaxation Ferroelectrics, and concrete parameters is as shown in table 1.

Table 1BaTiO ₃+ xmol%BiYO ₃the T of (x=0 ~ 30) pottery _m, T _c, T _cw, △ T _m, ε _m, γ, △ T _difwith △ T _relax

T _mit is specific inductivity maximum value corresponding temperature; T _cit is Curie-point temperature; T _cwit is the temperature that change in dielectric constant starts to follow corresponding to Curie-Weiss law; △ T _m=T _cw-T _m; ε _m-specific inductivity maximum value; γ is disperse index; △ T _difthe parameter △ T of exosyndrome material Phase Transformation Diffusion degree _difbe defined as T _dif1kHz=T _{0.9 ε m1kHz}-T _{ε m1kHz}; △ T _relaxbe the parameter describing frequency dispersion degree under 1kHz ~ 1000kHz, be defined as T _relax=T _m1000kHz-T _m1kHz.

By doping BiYO ₃, and and BaTiO ₃form sosoloid, Curie peak is moved to low temperature direction, can also sintering temperature be reduced; Along with BiYO ₃the increase of content, can make grain refining.Meanwhile, form the fluctuating of micro components, composition fluctuation theory proposes based on compound ion stochastic distribution phenomenon.Think that different ions such as to occupy at random at the isomorphous position, produce microscopic concentration and the different microcell of integral macroscopic concentration, form different microcell and there is slightly different Curie temperature, macroscopically produce the transition temperature area of broadening, even if the average component of microcell is identical, also may form the different microcell of structure due to cell configuration difference, thus produce Diffuse phase transition.By adulterating or changing the scantlings of the structure of crystal grain, the Curie temperature of ferroelectric ceramic(s) can be made to change, the specific inductivity of peak value both sides rises, namely the warm curve that is situated between becomes more extensive, smooth, this by adulterating or changing the effect that crystalline-granular texture size improves the temperature stability of ceramic dielectric constant, be called broadening effect.BaTiO prepared by the present invention ₃base unleaded relaxation type ceramic dielectric material, not only preparation technology is simple, the cost of material is low, and have higher specific inductivity, low dielectric loss, and being expected to alternative lead base stupalith becomes one of laminated ceramic capacitor important candidate material double excellent technically and economically.

Claims (8)

1. a BiYO ₃doping BaTiO ₃base relaxation ferroelectric, is characterized in that, it is prepared material and comprises BaTiO ₃+ xmol%BiYO ₃, wherein x=2 ~ 30, xmol% represents molar percentage.

2. a BiYO ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, comprises the following steps:

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, in 1120 ~ 1150 DEG C of insulations 2 ~ 3 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, in 920 ~ 940 DEG C of insulations 2 ~ 3 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ xmol%BiYO ₃form mixture C after mixing, wherein x=2 ~ 30, x is molar percentage, by mixture C and zirconium ballstone and deionized water, is carry out ball milling, oven dry, granulation successively after 1:1:1 mixing, sieve, forms granulation material according to mass ratio;

Step 4: step 3 gained granulation material is made sample under the pressure of 110 ~ 120MPa, then carries out once sintered;

Step 5: in polishing, cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, carry out double sintering, obtain BiYO ₃doping BaTiO ₃base relaxation ferroelectric.

3. a kind of BiYO according to claim 2 ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, it is characterized in that, in step 3, mixture C mixes with zirconium ballstone and deionized water, ball milling, formed to dry after oven dry and expect, by mass concentration be 4 ~ 6% tackiness agent be added into dry material in carry out granulation, tackiness agent accounts for dries 8 ~ 10% of material quality, crosses 40 orders and 80 mesh sieves respectively and gets middle material, form granulation material after granulation.

4. a kind of BiYO according to claim 3 ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, described tackiness agent is polyvinyl alcohol water solution.

5. a kind of BiYO according to claim 2 ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, in step 3, Ball-milling Time is 4 ~ 6 hours.

6. a kind of BiYO according to claim 2 ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, in step 4, once sintered condition is: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1250 ~ 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, room temperature is cooled to the furnace.

7. a kind of BiYO according to claim 2 ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, in step 5, the condition of double sintering is: temperature is 600 ~ 620 DEG C, and the time is 20 ~ 30 minutes.

8. a BiYO ₃doping BaTiO ₃the preparation method of base relaxation ferroelectric, is characterized in that, comprises the following steps:

Step one: take BaCO according to mol ratio 1:1 ₃and TiO ₂be mixed to form mixture A, after mixture A is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 1150 DEG C of insulations 2 hours, form the BaTiO of pure phase ₃powder, for subsequent use;

Step 2: take Bi according to mol ratio 1:1 ₂o ₃and Y ₂o ₃be mixed to form mixture B, after mixture B is carried out ball milling, oven dry, briquetting, be placed in box-type furnace in 940 DEG C of insulations 2 hours, form the BiYO of pure phase ₃powder, for subsequent use;

Step 3: the BaTiO that step one is obtained ₃the BiYO that powder and step 2 obtain ₃powder is according to BaTiO ₃+ 30mol%BiYO ₃mixed in molar ratio after form mixture C, by mixture C and zirconium ballstone and deionized water, be the rear ball milling 4h of 1:1:1 mixing according to mass ratio, then dry formation oven dry material, by mass concentration be 6% polyvinyl alcohol water solution be added into dry material in carry out granulation, polyvinyl alcohol water solution accounts for dries 10% of material quality, after granulation, 40 orders and 80 mesh sieves get middle material excessively respectively, form granulation material;

Step 4: step 3 gained granulation material is made sample under the pressure of 120MPa, then, be placed in zirconium white be backing plate the inherent high temperature box furnace of aluminum oxide saggar in carry out once sintered: be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, 3 hours are incubated when being warming up to 1300 DEG C with 5 DEG C/min, afterwards, after being cooled to 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace;

Step 5: polishing, in cleaning step four after once sintered good sample, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of double sinterings 20 minutes, obtains BiYO ₃doping BaTiO ₃base relaxation ferroelectric.