CN104030678A - BaTiO3 based lead-free relaxation-type ceramic dielectric material and preparation method thereof - Google Patents

Abstract

The invention discloses a BaTiO3 based lead-free relaxation-type ceramic dielectric material and a preparation method thereof. The preparation method comprises the following steps: weighting and mixing BaCO3 and TiO2 so as to form a mixture; after the mixture is ball-milled, dried and briquetted, putting the obtained product into a box-type furnace to carry out heat preservation, so that pure-phase BaTiO3 powder is formed; adding Bi2O3 and Al2O3 into the pure-phase BaTiO3 powder so as to form a complete ingredient, and ball-milling, drying, granulating and sieving the complete ingredient so as to form a granulating material; preparing the granulating material into a sample, sintering the sample, coating a silver electrode liquid material on the sample, and then sintering the obtained product. The dielectric material disclosed by the invention is prepared by using a traditional solid phase method, so that the dielectric material is mature in process, and suitable for industrialized production. Due to the co-doping of Bi2O3 and Al2O3, electrovalence compensation is realized, thereby facilitating the implementation of diffuse phase transition of BaTiO3 ceramics. The dielectric material is simple in preparation process, low in material coat and environment-friendly, and the prepared lead-free relaxation-type ceramic dielectric material has relatively high dielectric constant and low dielectric loss.

Description

A kind of BaTiO 3the unleaded relaxation type of base ceramic dielectric material and preparation method thereof

Technical field

The invention belongs to ceramic dielectric material field, particularly a kind of BaTiO ₃the unleaded relaxation type of base ceramic dielectric material and preparation method thereof.

Background technology

Perovskite structure ferroelectrics is to study at present a class ferroelectrics the most widely, and its skeleton symbol is ABO ₃.Because distinctive how much free-running properties of perovskite structure can be held 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. synthesizes the lead magnoniobate with Relaxivity and has started the New Wave of relaxation ferroelectric research first.Be different from independent relaxation phenomena and ferroelectricity, unique relaxation behavior thinks that by traditional sense both break mutual unrelated saying, are called Relaxation Ferroelectrics by people by both perfect adaptations together.Compared with common ferroelectrics, topmost two the feature disperse phase transformations in relaxation ferroelectric dielectric properties aspect and frequency dispersion.

At present, there have been many scholars to BaTiO ₃the unleaded relaxation ferroelectric ceramic material of base conducts extensive research.Henan ferroelectrics not only has high dielectric properties, and relatively low firing temperature also has the low temperature coefficient of capacitance being caused by " disperse phase transformation ".No matter be therefore preparation technology aspect or aspect with low cost, be all considered to substitute the only choosing of laminated ceramic capacitor.

Summary of the invention

The object of the present invention is to provide a kind of BaTiO ₃base lead-free ceramics dielectric substance and preparation method thereof, not only preparation technology is simple, and the cost of material is low, and have higher specific inductivity, low dielectric loss.

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

A kind of BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture;

Step 2: mixture is carried out after ball milling, oven dry, briquetting, be placed in box-type furnace in 1130-1170 DEG C of insulation 2-3 hour, form the BaTiO of pure phase ₃powder;

Step 3: with the BaTiO of pure phase ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃with x mol%Al ₂o ₃be added into the BaTiO of pure phase ₃in powder, form batching entirely, will entirely prepare burden and carry out ball milling, oven dry, granulation, sieve, form granulation material; Wherein, x=0.00～3.00;

Step 4: granulation material is made to sample, then be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1230～1290 DEG C with 5 DEG C/min, be incubated 2-3 hour, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: after the sample sintering is polished, cleaned, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20-30 minute, obtain BaTiO ₃the unleaded relaxation type of base ceramic dielectric material.

In described step 3, ball milling specifically will be prepared burden and zirconium ballstone, deionized water entirely, be to carry out after 1:1:1 mixes according to mass ratio.

In described step 3, Ball-milling Time is 3-4 hour.

In described step 3, after full batching, zirconium ballstone and deionized water mixing, ball milling, oven dry, form oven dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for and dries 8～10% of material quality.

Described tackiness agent is that mass concentration is 4～6% polyvinyl alcohol water solution.

In described step 3, x is 0,0.25,0.75,1.00,2.00 or 3.00.

In described step 4, granulation material is to make sample under the pressure of 120MPa.

The BaTiO being made by aforesaid method ₃base lead-free ceramics dielectric substance, described BaTiO ₃the major ingredient of base lead-free ceramics dielectric substance is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃; According to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the xmol% of major ingredient, wherein, x=0.00～3.00.

According to molar percentage meter, described x is 0,0.25,0.75,1.00,2.00 or 3.00.

Compared with prior art, the beneficial effect that the present invention has: doping Bi ³⁺replace Ba ²⁺the relaxation behavior that can strengthen, at BaTiO ₃b position doped with Al ³⁺can reduce T _m.At BaTiO ₃a position doping Bi ³⁺can cause not mating of ionic radius, the Al of B position doping ³⁺can cause valence fluctuation and local heterogeneous.In order to obtain relaxation behavior when the low temperature, the present invention is at BaTiO ₃a position doping Bi ³⁺, simultaneously in B position doped with Al ³⁺.By to prepared ceramic dielectric performance analysis, it there is relaxation phenomena in digital proof, meets topmost two the feature disperse phase change characteristics in relaxation ferroelectric dielectric properties aspect and frequency dispersion characteristic, in actual applications alternative non-plumbum ferroelectric body.The present invention also has the following advantages: 1. adopt conventional solid-state method preparation, technical maturity, is applicable to industrialization and produces.2. adopt Bi ₂o ₃and Al ₂o ₃carry out codoped, realize electricity price compensation and be conducive to realize BaTiO ₃the disperse phase transformation of pottery.3. not only preparation technology is simple for method of the present invention, the cost of material is low and environmental protection, and preparation unleaded relaxation type ceramic dielectric material there is higher specific inductivity, low dielectric loss, to substitute lead base stupalith become laminated ceramic capacitor technically and economically hold concurrently excellent important candidate material.

Brief description of the drawings

Fig. 1 (a) is the rational curve that the dielectric constant with temperature of embodiment 1 sample changes, and Fig. 1 (b) is that embodiment 1 sample is at the contrary dielectric constant with temperature change curve for ceramic under 1kHz;

Fig. 2 (a) is the temperature variant rational curve of temperature coefficient of capacitance of embodiment 2 samples, and Fig. 2 (b) is that embodiment 2 samples are at the contrary dielectric constant with temperature change curve for pottery under 1kHz;

Fig. 3 (a) is the rational curve that the dielectric constant with temperature of embodiment 3 samples changes, and Fig. 3 (b) is that embodiment 3 samples are at the contrary dielectric constant with temperature change curve for ceramic under 1kHz;

Fig. 4 (a) is the temperature variant rational curve of temperature coefficient of capacitance of embodiment 4 samples, and Fig. 4 (b) is that embodiment 4 samples are at the contrary dielectric constant with temperature change curve for pottery under 1kHz;

Fig. 5 (a) is the rational curve that the dielectric constant with temperature of embodiment 5 samples changes, and Fig. 5 (b) is that embodiment 5 samples are at the contrary dielectric constant with temperature change curve for ceramic under 1kHz;

Fig. 6 (a) is the temperature variant rational curve of temperature coefficient of capacitance of embodiment 6 samples, and Fig. 6 (b) is that embodiment 6 samples are at the contrary dielectric constant with temperature change curve for pottery under 1kHz;

Fig. 7 is ln (1/ ε-1/ ε of embodiment 1～6 sample _m)～ln (T-T _m) curve;

Fig. 8 is the lnf～T of embodiment 6 samples _mcurve.

Embodiment

Below in conjunction with accompanying drawing, by embodiment, the present invention is described in detail.

Embodiment 1

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃, Bi ₂o ₃account for the 0.5mol% of major ingredient.

Above-mentioned BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material is as follows:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching;

To entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dries and form oven dry material, tackiness agent is added into dry in material and carries out granulation, then crosses respectively 40 orders and 80 mesh sieves and get middle material, obtains granulation material; Wherein, tackiness agent accounts for dries 8% of material quality, and tackiness agent is that mass concentration is 4% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1290 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 2

BaTiO of the present invention ₃basic ring is protected relaxation type ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃, according to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 0.25mol% of major ingredient.

BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 0.25mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching, to entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 9% of material quality, and tackiness agent is that mass concentration is 6% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1270 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 3

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃, according to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 0.75mol% of major ingredient.

BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃, for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 0.75mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching, to entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 10% of material quality, and tackiness agent is that mass concentration is 5% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1250 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 4

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃, according to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 1.00mol% of major ingredient.

BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 1.00mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching, to entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 9% of material quality, and tackiness agent is that mass concentration is 6% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1250 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 5

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃, according to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 2.00mol% of major ingredient.

BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 2.00mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching, to entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 9% of material quality, and tackiness agent is that mass concentration is 4% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1230 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: after polishing, the sample that sinters of cleaning step five, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 6

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃, according to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 3.00mol% of major ingredient.

BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, comprises the following steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1150 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 3.00mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching, to entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 8% of material quality, and tackiness agent is that mass concentration is 5% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1230 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Refer to shown in Fig. 1 to Fig. 8, dielectric properties test shows: embodiment 1 to embodiment 6 prepared ceramic medium material all meets Relaxation Ferroelectrics, and concrete parameters is as shown in table 1.

The T of the prepared stupalith of table 1 embodiment 1-6 _m, T _c, T _cw, △ T _m, ε _m, γ, △ T _difwith △ T _relax

In table, T _mit is specific inductivity maximum value corresponding temperature; T _cit is Curie-point temperature; T _cwthat change in dielectric constant starts to follow the corresponding temperature of 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 of describing frequency dispersion degree under 1kHz～1000kHz, be defined as T _relax=T _m1000kHz-T _m1kHz.

As can be seen from Figure 7, ferroelectric-para-electric phase transformation diffusion parameter has departed from concrete Curie-Weiss law, but still follows general Curie-weiss relational expression:

$\frac{1}{\mathrm{\ϵ}}-\frac{1}{{\mathrm{\ϵ}}_m}=\frac{{(T-T_m)}^{\mathrm{\γ}}}{C},(1\≤\mathrm{\γ}\≤2)---(1-1)$

In formula: ε _m-specific inductivity maximum value, ε-specific inductivity, T _m-transformation temperature, C-Curie-Weiss constant, γ-disperse index, by carrying out matching with formula, the straight slope obtaining is γ.

Fig. 8 is 1000/T _m～lnf curve and formula (1-2) matched curve, carries out matching by experiment the data obtained and Vogel-Fulcher equation, by calculating the E of prepared stupalith _afor 0.0678eV, T _ffor 382.28K, f ₀be 1.76 × 1018Hz.From Fig. 8, also can find out that experiment the data obtained conforms to substantially with Vogel-Fulcher matched curve, the process of stupalith frequency of occurrences dispersion meets vitreous state model.

Vogel-Fulcher equation is:

$f-f_0\exp \left(\frac{-E_a}{k_B(T_m-T_f)}\right)---(1-2)$

In formula: f ₀-pre-exponent, E _a-intensity of activation, k _b-Boltzmann constant, T _f-freezing temperature.

As can be seen from the above table by doping Bi ₂o ₃and Al ₂o ₃, and and BaTiO ₃form sosoloid, can effectively improve Curie temperature, Curie peak is moved to high temperature direction, can also reduce sintering temperature; Along with Al ₂o 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 occupies at random at the isomorphous position, produce the different microcell of microscopic concentration and integral macroscopic concentration, form different microcell and there is slightly different Curie temperature, in macroscopic view, produce the transition temperature area of broadening, even if the average component of microcell is identical, also may form because cell configuration is different the different microcell of structure, thereby produce disperse phase transformation.By adulterating or changing the scantlings of the structure of crystal grain, can make the Curie temperature of ferroelectric ceramic(s) change, the specific inductivity of peak value both sides rises, the warm curve that is situated between becomes more extensive, smooth, this by adulterating or changing crystalline-granular texture size and improve the effect of the temperature stability of ceramic dielectric constant, be called broadening effect.The BaTiO that the present invention is prepared ₃the unleaded relaxation type of base 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 substitute lead base stupalith becomes one of double excellent technically and economically important candidate material of laminated ceramic capacitor.

Embodiment 7

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃, Bi ₂o ₃account for the 0.5mol% of major ingredient.

Above-mentioned BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material is as follows:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1130 DEG C of insulations 2 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching;

To entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 3h after 1:1:1 mixes according to mass ratio, then dries and form oven dry material, tackiness agent is added into dry in material and carries out granulation, then crosses respectively 40 orders and 80 mesh sieves and get middle material, obtains granulation material; Wherein, tackiness agent accounts for dries 8% of material quality, and tackiness agent is that mass concentration is 6% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1240 DEG C with 5 DEG C/min, be incubated 3 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 30 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 8

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 2.5mol% of major ingredient.

Above-mentioned BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material is as follows:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1170 DEG C of insulations 2.5 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 2.5mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching;

To entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 3.5h after 1:1:1 mixes according to mass ratio, then dry to form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for dries 9% of material quality, and tackiness agent is that mass concentration is 5% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1280 DEG C with 5 DEG C/min, be incubated 2.5 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 25 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Embodiment 9

BaTiO of the present invention ₃the unleaded relaxation type of base ceramic dielectric material, comprises major ingredient and auxiliary material, and major ingredient is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the 1.5mol% of major ingredient.

Above-mentioned BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material is as follows:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture.

Step 2: getting mixture and zirconium ballstone and deionized water, is to carry out successively after ball milling, oven dry, briquetting after 1:1:1 mixes according to mass ratio, is placed in box-type furnace respectively at 1160 DEG C of insulations 3 hours, forms the BaTiO of pure phase ₃powder, for subsequent use;

Step 3: with pure phase BaTiO ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃, 1.5mol%Al ₂o ₃add the BaTiO of pure phase to ₃in powder, after mixing, form full batching;

To entirely prepare burden and zirconium ballstone and deionized water, be to carry out successively ball milling 4h after 1:1:1 mixes according to mass ratio, then dries and form oven dry material, tackiness agent is added into dry in material and carries out granulation, then crosses respectively 40 orders and 80 mesh sieves and get middle material, obtains granulation material; Wherein, tackiness agent accounts for dries 10% of material quality, and tackiness agent is that mass concentration is 4% polyvinyl alcohol water solution.

Step 4: granulation material is made to sample under the pressure of 120MPa, then, be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1260 DEG C with 5 DEG C/min, be incubated 2 hours, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: polishing, clean after the sample that sinters, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20 minutes, obtain BaTiO ₃the unleaded relaxation type of base stupalith.

Claims (9)

1. a BaTiO ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: comprise the steps:

Step 1: preparation BaTiO ₃for subsequent use: according to mol ratio, 1:1 takes BaCO ₃and TiO ₂be mixed to form mixture;

Step 2: mixture is carried out after ball milling, oven dry, briquetting, be placed in box-type furnace in 1130-1170 DEG C of insulation 2-3 hour, form the BaTiO of pure phase ₃powder;

Step 3: with the BaTiO of pure phase ₃powder is 1mol meter, takes respectively 0.5mol%Bi according to molar content ₂o ₃with x mol%Al ₂o ₃be added into the BaTiO of pure phase ₃in powder, form batching entirely, will entirely prepare burden and carry out ball milling, oven dry, granulation, sieve, form granulation material; Wherein, x=0.00～3.00;

Step 4: granulation material is made to sample, then be placed in the inherent high temperature box furnace of aluminum oxide saggar taking zirconium white as backing plate, be warming up to 500 DEG C of insulation 60min with 2 DEG C/min, while being warming up to 1230～1290 DEG C with 5 DEG C/min, be incubated 2-3 hour, afterwards, be cooled to after 500 DEG C with 5 DEG C/min, cool to room temperature with the furnace, the sample that obtains sintering;

Step 5: after the sample sintering is polished, cleaned, evenly apply silver electrode paste at sample tow sides, in 600 DEG C of sintering 20-30 minute, obtain BaTiO ₃the unleaded relaxation type of base ceramic dielectric material.

2. a kind of BaTiO as claimed in claim 1 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: in described step 3, ball milling specifically will be prepared burden and zirconium ballstone, deionized water entirely, is to carry out after 1:1:1 mixes according to mass ratio.

3. a kind of BaTiO as claimed in claim 1 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: in described step 3, Ball-milling Time is 3-4 hour.

4. a kind of BaTiO as claimed in claim 1 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, it is characterized in that: in described step 3, after full batching, zirconium ballstone and deionized water mixing, ball milling, oven dry, form and dry material, tackiness agent is added into dry in material and carries out granulation, then cross respectively 40 orders and 80 mesh sieves and get middle material, obtain granulation material; Wherein, tackiness agent accounts for and dries 8～10% of material quality.

5. a kind of BaTiO as claimed in claim 4 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: described tackiness agent is that mass concentration is 4～6% polyvinyl alcohol water solution.

6. a kind of BaTiO as claimed in claim 1 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: in described step 3, x is 0,0.25,0.75,1.00,2.00 or 3.00.

7. a kind of BaTiO as claimed in claim 1 ₃the preparation method of the unleaded relaxation type of base ceramic dielectric material, is characterized in that: in described step 4, granulation material is to make sample under the pressure of 120MPa.

8. the BaTiO preparing according to the preparation method described in any one in claim 1 to 7 ₃base lead-free ceramics dielectric substance, is characterized in that: described BaTiO ₃the major ingredient of base lead-free ceramics dielectric substance is BaCO ₃and TiO ₂, its mol ratio is 1:1, auxiliary material is Bi ₂o ₃and Al ₂o ₃; According to molar percentage meter, Bi ₂o ₃account for the 0.5mol% of major ingredient, Al ₂o ₃account for the xmol% of major ingredient, wherein, x=0.00～3.00.

9. the BaTiO preparing according to preparation method claimed in claim 8 ₃base lead-free ceramics dielectric substance, is characterized in that: according to molar percentage meter, described x is 0,0.25,0.75,1.00,2.00 or 3.00.