CN1765797A - Production method of polycrystalline ceramic body - Google Patents

Abstract

To provide a production method of a polycrystalline ceramic body with excellent density, a preparation step, a mixing step, a forming step and a heat-treating step are performed. In the preparation step, a coarse particle ceramic powder, and a fine particle powder having an average particle diameter of 1/3 or less of the average particle diameter of the coarse particle ceramic powder are prepared. In the mixing step, the coarse particle ceramic powder and the fine particle powder are mixed to produce a raw material mixture. In the forming step, the raw material mixture is formed to a shaped body. In the heat-treating step, the shaped body is heated and thereby sintered to produce a polycrystalline ceramic body. In the heat-treating step, a temperature elevating process and a first holding process are performed and at the same time, a second holding process and/or a cooling process are performed. In the temperature elevating process, heating is started to elevate the temperature and in the first holding process, the shaped body is held at a temperature T1 DEG C. In the second holding process, the shaped body is held at a temperature T2 DEG C. lower than the temperature T1 DEG C. In the cooling process, the shaped body is cooled at a temperature dropping rate of 60 DEG C./h or less from the temperature T1 DEG C.

Description

The preparation method of polycrystalline ceramic body

Technical field

The present invention relates to a kind of preparation method of polycrystalline ceramic body.

Background technology

The polycrystal (polycrystalline ceramic body) that comprises pottery can be used for for example transmitter of temperature, heat, gas, ion etc., such as electronic circuit component and the light or the magnetic recording composition of electric capacity, resistance and surface-mounted integrated circuit.Especially, the polycrystalline ceramic body (hereinafter referred to as " piezoelectric ceramics ") with piezoelectric effect is because of its performance is good, shaping degree of freedom height and material design relatively simply just are being widely used in electronics or mechano-electronic field.

Piezoelectric ceramics is the direction of polarization of ferroelectric material is adjusted to a fixed-direction to make ferroelectric ceramic(s) stand so-called polarization to handle and obtain by applying electric field.In order in piezoelectric ceramics, to use polarization to handle and the fixed direction to be adjusted in spontaneous polarization, can be comparatively favourable at isotropic perovskite type crystal structure of three-dimensional space all directions spontaneous polarization.Therefore, the most of piezoelectric ceramics in the practical application are isotropic perovskite type ferroelectric ceramic.

The example of known isotropy perovskite type ferroelectric ceramic comprises Pb (Zr, Ti) O ₃(hereinafter referred to as " PZT "), by to PZT, BaTiO ₃And Bi _0.5Na _0.5TiO ₃Adding lead is the PZT ternary system (hereinafter referred to as " BNT ") that the compound uhligite is obtained.

In these examples, compare with other piezoelectric ceramics, be that the plumbous series piezoelectric ceramic of example has good piezoelectric property with PZT, it is in dominant position in the piezoelectric ceramics of practical application at present.Yet this piezoelectric ceramics contains the plumbous oxide (PbO) with high vapour pressure, and this has increased very big environmental pressure unfriendly.Therefore, need a kind of low lead or the unleaded piezoelectric ceramics suitable with the PZT piezoelectric property.

On the other hand, in leadless piezoelectric material material, a kind of BaTiO ₃Pottery has piezoelectric property relatively preferably, and is applied in systems such as sonar.Simultaneously, some BaTiO are also arranged ₃Sosoloid and another kind of unleaded type perovskite compound (as: BNT) have shown piezoelectric property relatively preferably.Yet the problem of these leadless piezoelectric ceramicss is its piezoelectric property piezoelectric properties not as PZT.

In order to address these problems, different piezoelectric ceramics has been proposed for this reason so far.

For example, the known piezoelectric ceramics that a kind of lead-free or its sosoloid are arranged, this piezoelectric ceramics comprises the potassium-sodium niobate of isotropy perovskite typed, and shows piezoelectric property (referring to Japanese unexamined patent open 2000-313664,2003-300776,2003-306479,2003-327472,2003-342069 and 2003-342071) preferably.

Yet the problem of these leadless piezoelectric ceramicss is that comparing its piezoelectric property with PZT type piezoelectric ceramics still can not be satisfactory.

In these cases, disclose a kind of piezoelectric element that comprises piezoelectric ceramics, this piezoelectric ceramics comprises a kind of ceramic crystalline grain (referring to the open 2004-7406 of Japanese unexamined patent) of the spontaneous polarization that contains anisotropic shape and be easy to be orientated in same plane.

Usually piezoelectric property that is known that the isotropy perovskite-type compounds etc. changes with crystalline axis direction.Therefore, can just can farthest utilize the anisotropy of piezoelectric property, and be expected to promote performance of piezoelectric ceramics to a fixed direction orientation if show the crystallographic axis of good piezoelectric property etc.Open 2004-7406 is disclosed as Japanese unexamined patent, by use tabular powder also particular crystal plane to be orientated according to certain method, can produce the pottery that a kind of wherein said particular crystal plane has the high-performance crystalline orientation of high-orientation as reactive template, this tabular powder of sintering and a kind of raw material powder with predetermined composition.

Yet, disadvantageously, when preparing polycrystalline ceramic body (pottery of crystalline orientation) by tabular powder with the raw material powder sintering as mentioned above, because be that tabular powder that granularity is different is with the raw material powder sintering, so can not obtain fine and close polycrystalline ceramic body.Especially, when using non-plumbous class material, very easy formation space (void) is arranged, seldom problem such as densification takes place.

The disadvantage that is formed with the polycrystalline ceramic body in space is its piezoelectric property such as piezoelectric constant d ₃₁And dielectric properties such as dielectric loss etc. can variation.In addition, it is former thereby produce problem such as break because of fatigue etc. to also have in use strength degradation and polycrystalline ceramic body to be easy to.

In general, in the sintering of pottery, along with the powder diameter as raw material diminishes, its specific surface area can become greatly, and it is higher that activity can become, and therefore, compares with the particle that particle diameter is bigger, can carry out sintering under lower temperature.Simultaneously, along with the particle diameter of the raw material powder homogeneous more that becomes, sinterability can become better, and densification also can easier acquisition.

And be intended to promote in the technology of ceramic crystal orientation above-mentioned, when sintering is used to accelerate the fine particle of raw material powder that the roughcast plate particle of crystalline orientation prepares and the auxiliary substance that is used to obtain the target pottery by fusion, because sinterability difference between fine particle and the roughcast plate particle is so sintering rate becomes inconsistent in roasting process.

For example, when raw material powder can make fine particle quicken to carry out roasting in the agglomerating temperature range, though the sintering of fine particle obtains quickening, roughcast plate particle was difficult to and fine particle carries out sintering together.Therefore, will form the space, thereby can not get fine and close sintered compact at the periphery of template particles.More specifically, at this in the case, though because the sintering process of fine particle is accelerated and can be obtained the low sintered compact of clearance gap rate (open porosity), but owing to there being fine particle around the template particles, the sintering of template particles is obstructed, so may residual closed down hole (space) in the sintered compact.Consequently, the bulk density of the sintered compact of acquisition reduces.

Otherwise when roasting is being higher than when being suitable for carrying out under the agglomerating temperature, what quicken to take place is particle growth rather than sintering, and this can cause particle growth takes place in fine particle, and between fine particle and template particles sintering and particle growth takes place.Under this temperature condition, in such as the raw material powder particle of fine powder and template powder, form firm combination, but sintering process is hindered.The clearance gap rate of the sintered compact that consequently, obtains increases.

This problem not only is present in the production of the polycrystalline ceramic body that comprises crystal oriented ceramic, also is present under the situation of many other preparation polycrystalline ceramic bodies.

In other words, so long as prepare polycrystalline ceramic body, the problem that is difficult to take place densification will be arranged by mixing and the different raw material powder of sintering particle diameter.

The present invention has considered the problem that these are traditional when carrying out, and the purpose of this invention is to provide the method that a kind of preparation has the polycrystalline ceramic body of excellent density.

Summary of the invention

The present invention is a kind of method for preparing polycrystalline ceramic body, and it comprises:

The preparation median size is the ceramic coarse particle powder of 1-20 μ m, with median size be the preparation process of 1/3 or littler particulate powders of described ceramic coarse particle powder median size, when described particulate powders and ceramic coarse particle powder sintering together, can produce polycrystalline ceramic body;

Described ceramic coarse particle powder is mixed with particulate powders producing the mixing step of raw mix,

Make described raw mix be shaped with the forming step that produces molding (a kind of powder agglomates) and

Heat described molding, described molding is shunk, the described ceramic coarse particle powder of sintering and particulate powders to be preparing the heat treatment step of polycrystalline ceramic body simultaneously,

Wherein, in described heat treatment step, implement the temperature-rise period and the first maintenance process, temperature-rise period begins to heat with elevated temperature to molding, the first maintenance process remained on 1 ℃ of temperature T following 0.1 minute or longer with molding, 600≤T1≤1 wherein, 500, implement second maintenance process and/or the process of cooling simultaneously, the second maintenance process with molding 2 ℃ of temperature T that keeps below 1 ℃ of temperature T following 10 minutes or longer, T2 〉=300 wherein, the described second maintenance process is after the first maintenance process, process of cooling begins molding is cooled off for 1 ℃ from temperature T with 60 ℃/h or lower rate of temperature fall, and described process of cooling is after the first maintenance process (claim 1).

In production method of the present invention, need to implement preparation process, mixing step, forming step and heat treatment step.

In preparation process, preparation ceramic coarse particle powder and particulate powders, the median size of wherein said ceramic coarse particle powder is 1-20 μ m, the median size of described particulate powders be ceramic coarse particle powder median size 1/3 or littler, when particulate powders can generate polycrystalline ceramic body during with ceramic coarse particle powder sintering.In mixing step, the ceramic coarse particle powder is mixed with particulate powders to produce raw mix subsequently.And then in forming step, raw mix is shaped to produce molding.Thereafter in heat treatment step, heat described molding so that its contraction, the described ceramic coarse particle powder of sintering and particulate powders are to prepare polycrystalline ceramic body simultaneously.

Like this, in the present invention, can be by molding being heated with sintering ceramic coarse particle powder and particulate powders prepare polycrystalline ceramic body thus.

Especially, in heat treatment step, need to implement the temperature-rise period and the first maintenance process, and implement second maintenance process and/or the process of cooling.More particularly, in heat treatment step, need to implement the temperature-rise period and the first maintenance process, and, the step that one of needs in the second maintenance process of implementing and the process of cooling, or implement the second maintenance process and two steps of process of cooling.

In temperature-rise period, begin to heat up by being heated into body, can begin molding is carried out sintering.In the first maintenance process, molding is remained on 1 ℃ of temperature T (condition is 600≤T1≤1,500) following 0.1 minute or longer.In the second maintenance process, molding remained below 2 ℃ of (condition are T2 〉=300) following 10 minutes or longer of temperature T of T1 ℃.In process of cooling, begin molding is cooled off from T1 ℃ with 60 ℃/h or lower rate of temperature fall.

Like this, molding begins sintering in the temperature-rise period and the first maintenance process, and meanwhile, particle growth obtains gratifying acceleration under top temperature T1 ℃, and the combination between combination between fine particle and coarse particles and fine particle can become firm thus.And then, in second incubation step and/or cooling step,, temperature can make in the scope that sintering proceeds by being rested on, can eliminate residual space.

When heating in the first maintenance process, the clearance gap rate probably increases, that is, though produce closed hole, be easy to generate many and the successive hole sintered compact external communications.Therefore, in the present invention, need to implement second maintenance process and/or the process of cooling, in the second maintenance process, with the temperature that is lower than T1 ℃ of the first insulation Heating temperature molding is heated, in process of cooling, with 60 ℃/h or lower rate of temperature fall molding is cooled off, thus, sintering can be proceeded under lower temperature, and can eliminate the hole by the agglomerating progress.

Therefore, can produce the polycrystalline ceramic body that the space is reduced and had excellent density.

As mentioned above, according to the present invention, can provide a kind of production method with polycrystalline ceramic body of excellent density.

Description of drawings

The result schematic diagram of Fig. 1 for obtaining during with ultrasonoscopy instrument observation polycrystalline ceramic body (sample E7) in the test case.

The result schematic diagram of Fig. 2 for obtaining during with ultrasonoscopy instrument observation polycrystalline ceramic body (sample C5) in the test case.

The result schematic diagram of Fig. 3 for obtaining during with ultrasonoscopy instrument observation polycrystalline ceramic body (sample C6) in the test case.

Embodiment

Embodiment of the present invention are as described below.

In production method of the present invention, need finish above-mentioned preparation process, mixing step, forming step and heat treatment step.

In preparation process, preparation ceramic coarse particle powder and particulate powders.

The ceramic coarse particle powder comprises pottery, and its median size is 1-20 μ m.

Can suitably select to constitute the pottery of described ceramic coarse particle powder, so that can obtain to comprise the polycrystalline ceramic body of required pottery.

If the median size of described ceramic coarse particle powder is less than 1 μ m, the present invention promotes the possibility of result of polycrystalline ceramic body density and can not be realized fully, if particle diameter surpasses 20 μ m, then can seriously reduce its sinterability, and behind sintering step, can not obtain the polycrystalline ceramics volume density of high sintered density.The preferred 1-13 μ of the median size of ceramic coarse particle powder m, more preferably 2-8 μ m.

Described ceramic coarse particle powder can have a kind of anisotropic shape.In the case, as hereinafter described, ceramic coarse particle powder (below be sometimes referred to as " powder of anisotropy shape ") with anisotropy shape of particular crystal plane orientation is oriented in forming step, subsequently, with this ceramic coarse particle powder as template with particulate powders sintering in heat treatment step, can produce the polycrystalline ceramic body that comprises crystal oriented ceramic thus, the certain surface that wherein constitutes the crystal grain of polycrystalline ceramic body is oriented.

The implication of " anisotropic shape " is as used herein, and laterally compares with the size of thickness direction, and size is bigger longitudinally for it.Shapes such as that its concrete preferred examples comprises is tabular, column, lamellar and needle-like.

The average aspect ratio of preferred ceramic coarse particle powder anisotropy shape is 3-100 (claim 8).

If the average aspect ratio of ceramic coarse particle powder is less than 3, when described in the back use ceramic coarse particle powder production comprises the polycrystalline ceramic body of crystal oriented ceramic, described ceramic coarse particle powder is difficult in a direction orientation, therefore may can not get comprising the polycrystalline ceramic body of required crystal oriented ceramic.On the other hand, if average aspect ratio surpasses 100, the intensity of described ceramic coarse particle powder will greatly reduce, and the ceramic coarse particle powder may break when forming step.If obtain to comprise the polycrystalline ceramic body of the crystal oriented ceramic with high-orientation, the aspect ratio of preferred ceramic coarse particle powder is 5 or higher, more preferably 10 or higher.Average aspect ratio is the mean ratio of the greatest dimension/smallest dimension of ceramic coarse particle powder.

The median size of particulate powders be the coarse grain powder median size 1/3 or littler.The median size of preferred particulate powders be coarse grain powder median size 1/5 or littler, more preferably 1/10 or littler.In the case, implementation result of the present invention can significantly be brought into play, and can obtain having the polycrystalline ceramic body of excellent density.In addition, the preferred 4 μ m or littler of the median size of particulate powders.In the case, can obtain having the polycrystalline ceramic body of more excellent plasticity.The median size of described particulate powders is 2 μ m or littler more preferably, further 1 μ m or littler more preferably.

For instance, described particulate powders can be the ceramic powder that generates polycrystalline ceramic body during with ceramic coarse particle powder sintering.Particulate powders can have with the ceramic coarse particle powder in ceramic phase with composition, perhaps have different compositions.

Be used for the composition of the polycrystalline ceramic body that the ceramic species of ceramic coarse particle powder and particulate powders can be as requested and suitably select.

Subsequently, in mixing step, the ceramic coarse particle powder is mixed with particulate powders to produce raw mix.

In mixing step, preferably the ceramic coarse particle powder is mixed with particulate powders, so that the blended ratio of ceramic coarse particle powder is per 100 weight part ceramic coarse particle powder and particulate powders total amount 0.01-70 weight part ceramic coarse particle powder (claim 2).

For instance, if the blended ratio of ceramic coarse particle powder is lower than 0.01 weight part, so, when preparation comprises the polycrystalline ceramic body of crystal oriented ceramic, the orientation degree of crystal oriented ceramic may reduce, if and, then can seriously reduce its sinterability, thereby behind heat treatment step, can not obtain the polycrystalline ceramic body of high sintered density above 70 weight parts.The preferred 0.1-50 weight part of the blended ratio of ceramic coarse particle powder, more preferably 1-10 weight part.

In forming step, raw mix is shaped to produce molding (powder agglomates)., in heat treatment step implement temperature-rise period and first maintenance process, implement second maintenance process and/or the process of cooling simultaneously thereafter, be heated into body (powder agglomates) thus so that its contraction, simultaneously, sintering ceramic coarse particle powder and particulate powders, the result has prepared polycrystalline ceramic body.

In temperature-rise period, begin to heat up by being heated into body (powder agglomates).

In temperature-rise period, preferably control contraction that temperature rise rate makes that molding (powder agglomates) causes because of being heated with 25%/or linear shrinkage speed still less (claim 6) takes place.

If linear shrinkage speed surpasses 25%/h, the very easy space that produces in the temperature-rise period in molding.The preferred 10%/h of linear shrinkage speed or lower, more preferably 5%/h or lower, further 2%/h or lower more preferably.Simultaneously, from the angle of enhancing productivity, the preferred 0.1%/h of linear shrinkage speed or higher.

Linear shrinkage speed can be measured by for example thermomechanical analyzer (TMA).

In temperature-rise period, preferred control temperature rise rate makes contraction that molding causes because of being heated with near the generation of constant linear shrinkage speed (below be sometimes referred to as " obtaining a constant speed contraction factor "), and its temperature range is (T1-50) ℃-T1 ℃ (claim 7).

For near constant linear shrinkage speed, the scope of supposing temperature is (T1-50) ℃-T1 ℃, and the ceiling for accumulation contraction rate is A, and minimum linear contraction rate is B, B/A preferred 0.6 or higher then, more preferably 0.8 or higher, further more preferably 0.9 or higher.

In the case, molding has been avoided the unexpected volumetric shrinkage in temperature-rise period, and before forming firm combining between fine particle and coarse particles, fine particle has carried out sintering to each other, has therefore suppressed the generation in space.

Subsequently, in the first maintenance process, molding kept 0.1 minute or longer down in 1 ℃ of temperature T (condition is 600≤T1≤1,500).

If T1 be lower than 600 or 1 ℃ of temperature T under hold-time be less than 0.1 minute, the roasting of molding is just carried out unsatisfactorily, may not obtain fine and close polycrystalline ceramic body, if and T1 surpasses 1500, the clearance gap rate will increase, and may can not obtain fine and close polycrystalline ceramic body like this.

In the first maintenance process, maintenance temperature T 1 (℃) preferred 1000≤T1≤1300 (claims 3).

Simultaneously, preferred 30 minutes of hold-time when 1 ℃ of temperature T or longer, more preferably 60 minutes or longer.In addition, from preventing to increase the angle of clearance gap rate, preferred 2000 minutes of the upper limit of hold-time or shorter when 1 ℃ of temperature T, more preferably 600 minutes or shorter, further more preferably 300 minutes or shorter.

In the first maintenance process, 1 ℃ of the temperature T of preferred decision and temperature T 1 ℃ of hold-time down for making when molding during in 1 ℃ of following roasting of temperature T, the clearance gap rate becomes 10% or more hour 1 ℃ of temperature T and hold-time, more preferably make the clearance gap rate become 5% or littler, further more preferably make the clearance gap rate become 3% or more hour 1 ℃ of temperature T and hold-time.

The available following method of clearance gap rate is calculated.

At first, the dry weight of the polycrystalline ceramic body that obtains after the thermal treatment and the clearance gap difference of soaking the weight behind the full water calculates the volume in polycrystalline ceramic body split shed space.Then, by Archimedes's method, measure the volume of polycrystalline ceramic body behind the volume deduct the clearance gap part that calculates.

With the volume of the clearance gap cumulative volume (volume of clearance gap and the polycrystalline ceramic body volume sum of disregarding clearance gap) divided by polycrystalline ceramic body, the number that obtains multiply by 100 again, and its value just is the clearance gap rate of trying to achieve.

After the first maintenance process, implement second maintenance process and/or the process of cooling.

In the second maintenance process, molding kept 10 minutes down or the longer time in 2 ℃ of the temperature T that is lower than 1 ℃ of temperature T (condition is T2 〉=300).

If T2＜300, the roasting of molding may not be carried out satisfactorily so, and perhaps the space that produces in the first maintenance process may not be reduced satisfactorily.Temperature T 2 is preferably T2 〉=600.

If the hold-time under the T2, the space that produces in the first maintenance process may not be reduced satisfactorily so less than 10 minutes.Simultaneously, preferred 2000 minutes of the upper limit of the hold-time during temperature T 2 or shorter, otherwise the production efficiency of polycrystalline ceramic body will reduce.

In the second maintenance process, 2 ℃ of the temperature T of preferred decision and temperature T 2 ℃ of hold-times down for making when molding during in 2 ℃ of following roastings of temperature T, the clearance gap rate becomes 3% or more hour 2 ℃ of temperature T and hold-time, more preferably make the clearance gap rate become 2% or littler, further more preferably make the clearance gap rate become 1% or more hour 2 ℃ of temperature T and hold-time.

Maintenance temperature T 1 in the first maintenance process (℃) and the second maintenance process in maintenance temperature T 2 (℃) preferably satisfy 5≤(T1-T2)≤300 (claims 4).

If (T1-T2)＜5, the space in the molding may not be reduced satisfactorily, and if (T1-T2)＞300, the roasting of molding may not be carried out satisfactorily.In either case, the polycrystalline ceramic body that obtains may all can not be satisfactory aspect density.

In process of cooling, molding is cooled off from T1 ℃ with 60 ℃/h or lower rate of temperature fall.If rate of temperature fall surpasses 60 ℃/h, the space that produces in the first maintenance process may not be reduced satisfactorily.

The preferred 40 ℃/h of rate of temperature fall in the process of cooling or lower (claim 5), 20 ℃/h or lower more preferably, further 10 ℃/h or lower more preferably, further 5 ℃/h or lower more preferably again.Simultaneously, the preferred 1 ℃/h of rate of temperature fall or higher, otherwise the production efficiency of polycrystalline ceramic body may reduce.

In process of cooling, cooling can be performed until room temperature, but in order to shorten the time of whole process, process of cooling can only be carried out in the temperature range that sintering process is quickened.Like this, described process of cooling preferably proceed to (T1-500) ℃, more preferably to (T1-300) ℃, further more preferably to the temperature of (T1-100) ℃.

In production method of the present invention, polycrystalline ceramic body can be produced by implementing above-described a plurality of step.

In the present invention, can be by suitably being chosen in ceramic coarse particle powder and the particulate powders for preparing in the preparation process, producing the polycrystalline ceramic body of characteristics such as having different compositions, crystalline structure.

Preferred polycrystalline ceramic body comprises isotropic perovskite-type compounds as principal phase (claim 13).

In the case, can though produce a kind of not leaded but still (for example: piezoelectric constant d have good piezoelectric property ₃₁, electromechanical coupling factor Kp, piezoelectricity g ₃₁Constant) and dielectric properties (for example: relative permittivity ε _33T/ ε ₀, dielectric loss tan δ) polycrystalline ceramic body.

Simultaneously, preferred described polycrystalline ceramic body comprises the pottery of crystalline orientation, and wherein the particular crystal plane A of each crystal grain is oriented (claim 9) in this crystal oriented ceramic.

Like this, just can produce the more excellent polycrystalline ceramic bodies of performance such as a kind of piezoelectric property, dielectric properties.

The example of this crystal oriented ceramic comprises by the represented isotropy perovskite-type compounds of following chemical formula (1) those potteries as principal phase:

{Li _x(K _1-yNa _y) _1-x}(Nb _1-z-wTa _zSb _w)O ₃

(wherein: 0≤x≤0.2,0≤y≤1,0≤z≤0.4,0≤w≤0.2 and x+z+w＞0)

The implication of " particular crystal plane A is oriented " can be in two kinds of situation: a kind of situation is, the arrangement of every kind of crystal grain makes and for example comprises particular crystal plane A (this state is designated hereinafter simply as " planar orientation ") parallel to each other by the crystal oriented ceramic of the represented compound of chemical formula (1); Another kind of situation is that the arrangement of every kind of crystal grain makes particular crystal plane A be parallel to an axle (this state is designated hereinafter simply as " axle orientation ") that passes polycrystalline ceramic body.

For instance, can be according to the spontaneous polarization direction that comprises by the crystal oriented ceramic of the represented compound of chemical formula (1) or other compound, or wait the kind of selecting to be orientated crystal face A according to the purposes of described crystal oriented ceramic, desired performance.That is: crystal face A can be selected from pseudo-cube (pseudo-cubic) { 100} plane, pseudo-cube of { 110} plane and pseudo-cube { 111} plane etc. according to purpose.

The implication of " pseudo-cube { HKL} " is, usually has the cubic crystal structure of distortion a little though comprise the crystal oriented ceramic of isotropy perovskite-type compounds etc., as tetragonal crystal, quadrature crystal or trigonal crystal, because distortion is smaller, therefore its structure still is considered to cubic system, and expresses with mirror image index (Mirror index).

At particular crystal plane A is under the situation of planar orientation, and the planar orientation degree can be represented with average orientation F{HKL} according to following mathematical formula 1 represented Lotgering method:

(mathematical expression 1)

$F\left(\mathrm{HKL}\right)=\frac{\frac{{\mathrm{\Σ}}^{\′}I\left(\mathrm{HKL}\right)}{\mathrm{\ΣI}\left(\mathrm{hkl}\right)}-\frac{{\mathrm{\Σ}}^{\′}{I}_0\left(\mathrm{HKL}\right)}{\mathrm{\Σ}{I}_0\left(\mathrm{hkl}\right)}}{1-\frac{{\mathrm{\Σ}}^{\′}{I}_0\left(\mathrm{HKL}\right)}{\mathrm{\Σ}{I}_0\left(\mathrm{hkl}\right)}}\×100(\%)$

In mathematical formula 1, the summation of the X-ray diffraction intensity of all crystal faces (hkl) that ∑ I (hkl) records for crystal oriented ceramic, ∑ I ₀(hkl) the X-ray diffraction intensity summation of all crystal faces (hkl) that record for the non-orientation ceramic that has with the crystal oriented ceramic same composition, ∑ ' the X-ray diffraction intensity summation of suitable particular crystal plane (HKL) on the crystallography that records for crystal oriented ceramic of I (HKL), ∑ ' I ₀(HKL) the X-ray diffraction intensity summation of suitable particular crystal plane (HKL) on the crystallography that records for the non-orientation ceramic that has with the crystal oriented ceramic same composition.

Therefore, when each crystal grain of forming polycrystalline ceramic body all is not orientated, its average orientation F (HKL) becomes 0%, and when (HKL) plane of all crystal grains of forming polycrystalline ceramic body all when being parallel to measurement plane and being orientated, its average orientation F (HKL) becomes 100%.

In crystal oriented ceramic, when the ratio of orientation crystal grain was higher, the performance of acquisition was also better.For example, under the situation to certain particular crystal plane planar orientation, in order to obtain good piezoelectric property etc., the measured average orientation F (HKL) of Lotgering method that represents according to mathematical formula 1 is preferably 30% or bigger.More preferably described average orientation is 50% or bigger.Particular crystal plane to be orientated is preferably and the vertical plane of polaxis.Under crystal type was situation as the tetragonal crystal of perovskite-type compounds, particular crystal plane A to be orientated was preferably { 100} face.

Preferably in polycrystalline ceramic body, { the 100} plane is orientated as crystal face A, and its orientation degree is 30% or bigger (claim 10) according to the puppet of Lotgering method cube.

Particular crystal plane A is being done under the situation of axle orientation, orientation degree (mathematical formula 1) when orientation degree can not be according to planar orientation is done same definition, but the axle orientation degree can be when carrying out the X-ray diffraction on perpendicular to the plane of axis of orientation Lotgering (HKL) diffraction method, expresses (hereinafter referred to as " axle orientation degree ") with average orientation.The particular crystal plane A almost completely axle orientation degree of the polycrystalline ceramic body in when orientation axle extremely approaches the orientation degree of the polycrystalline ceramics axon that particular crystal plane almost completely records during planar orientation.

Under the polycrystalline ceramic body that comprises above-mentioned crystal oriented ceramic comprises as the situation of perovskite-type compounds as principal phase, wherein use those polycrystalline ceramic bodies of non-plumbous class piezoelectric ceramics to show good piezoelectric property etc.In addition and since in the crystal oriented ceramic particular crystal plane of each crystal grain all towards direction orientation, according to comparing with having the non-orientation type sintered compact that contains same composition, described polycrystalline ceramic body can show good piezoelectric property etc.

More specifically, comprise by the forming of the crystal oriented ceramic of the represented compound of chemical formula (1), orientation degree and working condition etc., obtainable room temperature lower piezoelectric constant d by optimization ₃₁Be to have 1.1 times of polycrystalline ceramic body of the non-orientation sintered compact of same composition or higher.Simultaneously, by more optimizing these conditions, the room temperature piezoelectric constant d of the polycrystalline ceramic body of acquisition ₃₁Can reach 1.2 times of polycrystalline ceramic body with the non-orientation sintered compact of same composition or higher, or even can reach 1.3 times by continuing to optimize these conditions better.

Comprise and have the complicated polycrystalline ceramic body of forming by the pottery of each homogeny perovskite-type compounds of the represented compound of chemical formula (1) and can produce by the following method usually: the simple compounds that will contain component mixes to reach the stoichiometric ratio of target, form mixture thus, interim roasting and grinding form and mixture that sintering ground again.Yet, be difficult to produce the crystal oriented ceramic of the particular crystal plane of each crystal grain by this method to certain specific direction orientation.

Correspondingly, preferably the coarse particles that contains of ceramic coarse particle powder has the plane of orientation (orientation plane) that forms by the particular crystal plane orientation, the plane of orientation (orientation plane) in coarse particles has the lattice that is complementary with the particular crystal plane A that constitutes polycrystalline ceramic body, in forming step, form so that (claim 11) almost arranged to equidirectional in the coarse grained plane (orientation plane) that has been orientated.

In the case, can easily obtain a kind of polycrystalline ceramic body that contains the pottery of crystalline orientation, and particular crystal plane A presses orientation as described above in crystal oriented ceramic.

More specifically, the coarse particles that is comprised when ceramic coarse particle powder (following abbreviate as sometimes " the first anisotropy shape powder ") (following abbreviate as sometimes " the first orientation particle ") is when having the orientation plane that forms through the particular crystal plane orientation, having the be complementary orientation plane of lattice of particular crystal plane A with above-mentioned formation polycrystalline ceramic body is orientated in forming step, the first anisotropy shape powder becomes template or reactive template in heat treatment step, the first anisotropy shape powder so just can be produced the polycrystalline ceramic body that for example comprises by the crystal oriented ceramic of the represented compound of chemical formula (1) easily with particulate powders sintering or reaction and sintering.

The lattice match performance can be represented with the lattice match rate.

For instance, below by being that the example of metal oxide is described the lattice match performance with reference to the first orientation particle wherein.For example, if contain in the first orientation orientation of particles planar two-dimensional crystal lattice and contain the Sauerstoffatom lattice point in the two-dimensional crystal lattice of the particular crystal plane A that is orientated in Sauerstoffatom lattice point or containing metal atomic lattice point and the polycrystalline ceramic body or containing metal atomic lattice point has dependency, so just claim this two plane lattices to mate.

The value of lattice match rate for obtaining by the following method: with the absolute value of the difference of the lattice dimensions of similar position on the particular crystal plane A that is orientated in orientation planar lattice dimensions and the polycrystalline ceramic body in the first orientation particle, divided by orientation planar lattice dimensions in the first orientation particle, and recently express with percentage.

Lattice dimensions is the distance between the lattice point in the two-dimensional crystal lattice of a crystal face, and methods such as available X-ray diffraction and electron beam diffraction record by the analyzing crystal structure.In general, the lattice match rate is more little, and the lattice match of the first orientation particle and crystal face A is just good more, and it just can play better template action.

In order to obtain to have the crystal oriented ceramic of high-orientation, the first orientation particulate lattice match rate preferred 20% or littler, more preferably 10% or littler, further more preferably 5% or littler.

The orientation plane is preferably pseudo-cube { 100} plane (claim 12).

In the case, can produce a kind of polycrystalline ceramic body, this polycrystalline ceramic body is in the axis of orientation tetragonal crystal zone consistent with polaxis, and the offset table that is produced under big effect of electric field reveals excellent temperature dependency.

In the first orientation particle, the orientation plane is preferably the plane that occupies maximum area in the first orientation plane.

In the case, the first orientation plane can be the better reactive template that is used to produce the polycrystalline ceramic body that comprises crystal oriented ceramic.

Below describe the first orientation particle, promptly have the orientation planar coarse particles that forms through the particular crystal plane orientation, described orientation plane has the lattice that is complementary with the particular crystal plane A that constitutes polycrystalline ceramic body.

For instance, for the first orientation particle, can use those compounds that comprise perovskite-type compounds etc.

More specifically, can be used as the described first orientation particle with the pottery of target polycrystalline ceramic body, the compound that for example has a same composition by the represented isotropic perovskite-type compounds of chemical formula (1).

Also have, the first orientation particle not necessarily needs with the pottery of target polycrystalline ceramic body, for example has identical forming by the represented compound of chemical formula (1), if in heat treatment step, can produce a kind of pottery that comprises target isotropy perovskite-type compounds etc. during with the particulate powders sintering, just enough use.Correspondingly, the first orientation particle can all contain the compound of one or more elements and sosoloid etc. from each to be chosen, and these elements belong to the cation element that is comprised in the pottery of wanting to produce as the isotropy perovskite-type compounds.

Concerning the employed material of the first orientation particle that satisfies above-mentioned condition, for example, can use by the represented compound of following chemical formula (2), this compound is a kind of isotropic perovskite-type compounds, as: NaNbO ₃(being designated hereinafter simply as " NN "), KNbO ₃(being designated hereinafter simply as " KN ") or (K _1-yN _Ay) NbO ₃(0＜y＜1), or come from the compound that Li, Ta with predetermined amount and/or Sb substitute the dissolved solids of these compounds.

{Li _x(K _1-yNa _y) _1-x}(Nb _1-z-wTa _zSb _w)O ₃ (2)

(wherein, x, y, z and w are: 0≤x≤1,0≤y≤1,0≤z≤1 and 0≤w≤1)

The represented isotropy perovskite-type compounds of compound that chemical formula (2) is represented and chemical formula (1) has excellent lattice matching certainly.Therefore, when producing the represented crystal oriented ceramic of chemical formula (1), reacting property template action be the powder that comprises the first represented orientation particulate first anisotropy shape of chemical formula (2), the described first orientation particulate orientation plane for polycrystalline ceramic body in the plane (following this powder of special title is " powders A of anisotropy shape ") that is complementary of crystal face A lattice.Further, the powders A of anisotropy shape basically in the isotropy perovskite-type compounds by chemical formula (1) expression contained cation element constitute, therefore, when using the powders A of described anisotropy shape, can produce the significantly pottery of the crystalline orientation of minimizing of impurity element.In these particles, { 100} planar plate-like particles is preferably the orientation particle for pseudo-cube to comprise the represented compound of chemical formula (2), orientation plane.More preferably comprise NN or KN, orientation plane and be pseudo-cube { 100} planar plate-like particles.

Concerning as the material of the first anisotropy shape powder, for example, can use lamellated perovskite-type compounds, the crystal face A lattice match of the crystal face that has little surface energy in this compound and the polycrystalline ceramic body that comprises the represented compound of chemical formula (1) etc.The lattice anisotropy of layered perovskite-type compounds is bigger, therefore, can synthesize relatively easily that to comprise laminated perovskite type compound, orientation plane be the powder (following this powder of special title for " the powder B of anisotropy shape ") of anisotropy shape with crystal face of little surface energy.

First example of laminated perovskite type compound that is suitable for constituting the powder B of anisotropy shape comprises by the represented bismuth laminated perovskite type compound of following chemical formula (3):

(Bi ₂O ₂) ²⁺(Bi _0.5Me _m-1.5NbmO _3m+1) ^2- (3)

(wherein m is 2 or bigger integer, Me be selected from Li, K and Na one of at least).

The represented compound of chemical formula (3) is characterised in that, { 001} planar surface energy is lower than the surface energy of other crystal face, therefore, use the represented compound of chemical formula (3) to be easy to synthesize so that { the 001} plane is the powder B of orientation planar anisotropy shape." { 001} plane " is (a Bi with the laminated perovskite type compound of bismuth as used herein ₂O ₂) ²⁺The plane that layer is parallel.In addition, the represented compound of chemical formula (3) { cube { there is fabulous lattice match on the 001} plane to the puppet of the isotropy perovskite-type compounds that 001} plane and chemical formula (1) are represented.

Therefore, comprise the represented compound of chemical formula (3), so that { the 001} plane serves as that to be suitable for as producing the orientation plane be puppet cube { the reactive template of 100} planar crystal oriented ceramic to the powder B of orientation planar anisotropy shape, that is, be suitable for powder as the first anisotropy shape.

In addition, when using when being optimized by the represented compound of chemical formula (3) and to forming of the particulate powders described later, can produce to comprise the crystal oriented ceramic of the represented isotropy perovskite-type compounds of chemical formula (1), can be substantially free of Bi thus with as A-position element as principal phase.

Second example that is suitable for constituting the laminated perovskite type compound of anisotropy shape powder B comprises Sr ₂Nb ₂O ₇Sr ₂Nb ₂O ₇{ 010} planar surface energy is lower than the surface energy of other crystal face, and cube { there is fabulous lattice match on the 110} plane to the puppet of the isotropy perovskite-type compounds that it and chemical formula (3) are represented.Therefore, comprise Sr ₂Nb ₂O ₇, so that { the 010} plane serves as that to be suitable for as preparation orientation plane be { the reactive template of 110} planar crystal oriented ceramic to the powder of the orientation planar first anisotropy shape.

The 3rd example of laminated perovskite type compound that is suitable for constituting the powder B of anisotropy shape comprises Na _1.5Bi _2.5Nb ₃O ₁₂, Na _2.5Bi _2.5Nb ₄O ₁₅, Bi ₃TiNbO ₉, Bi ₃TiTaO ₉, K _0.5Bi _2.5Nb ₂O ₉, CaBi ₂Nb ₂O ₉, SrBi ₂Nb ₂O ₉, BaBi ₂Nb ₂O ₉, BaBi ₃Ti ₂NbO ₁₂, CaBi ₂Ta ₂O ₉, SrBi ₂Ta ₂O ₉, BaBi ₂Ta ₂O ₉, Na _0.5Bi _2.5Ta ₂O ₉, Bi ₇Ti ₄NbO ₂₁And Bi ₅Nb ₃O ₁₅These compounds { cube { there is good lattice match on the 100} plane to the puppet of the isotropy perovskite-type compounds that 001} plane and chemical formula (1) are represented, therefore, comprise this compound, so that { the 001} plane serves as that to be suitable for as producing the orientation plane be puppet cube { the reactive template of 100} planar crystal oriented ceramic to the powder of the orientation planar first anisotropy shape.

The 4th example that is suitable for constituting the laminated perovskite type compound of anisotropy shape powder B comprises Ca ₂Nb ₂O ₇And Sr ₂Ta ₂O ₇These compounds { cube { there is good lattice match on the 110} plane to the puppet of the isotropy perovskite-type compounds that 010} plane and chemical formula (1) are represented, therefore, comprise this compound, so that { the 010} plane serves as that to be suitable for as producing the orientation plane be puppet cube { the reactive template of 110} planar crystal oriented ceramic to the powder of the orientation planar first anisotropy shape.

The production method of the first anisotropy shape powder is as described below.

Oxide compound, carbonate and the nitrate (being designated hereinafter simply as " raw material of the production powder of anisotropy shape ") that contain the component that is useful on raw material by use, with the raw material of the production powder of described anisotropy shape with liquid or the material that becomes to liquid after being heated heat, just be easy to prepare the first anisotropy shape powder (that is: the powder B of anisotropy shape) that comprises laminated perovskite type compound with predetermined composition, median size and/or aspect ratio.

When the powder production raw material of anisotropy shape is heated in liquid phase so that during atomic dispersion, just can easily synthesize plane with little surface energy (for example, for the represented compound of chemical formula (3) be the 001} plane) the powder B of anisotropy shape of preferred growth.In the case, by suitable selection synthesis condition, average aspect ratio and the median size of may command anisotropy shape powder B.

The suitable example of the production method of the powder B of anisotropy shape comprises in the raw material of the production powder of anisotropy shape and (for example: the mixture of NaCl, KCl, NaCl and KCl, BaCl to add suitable flux ₂Or KF), and under preset temperature their method (flux method) of heating, and the method (hydrothermal synthesis) that in autoclave, has the aqueous solution of the amorphous powder of same composition and alkali to heat to a kind of powder B with anisotropy shape to be produced.

Otherwise, the anisotropy of the compound lattice that chemical formula (2) is represented is little, therefore, be difficult to directly syntheticly to comprise the represented compound of chemical formula (2), with the powder (that is, the powders A of anisotropy shape) of particular crystal plane as the orientation planar first anisotropy shape.Yet the powder B that the powders A of anisotropy shape can be by using the anisotropy shape is as reactive template and satisfy predetermined condition ground this powder of heating and reaction raw materials B produces (describing later on) in flux.

Synthesize as reactive template at the powder B that uses the anisotropy shape under the situation of powders A of anisotropy shape,, have only crystalline structure to change, and powder shape changes hardly if reaction conditions is optimized.

Can be easy to when being shaped towards the powders A of the anisotropy shape of a direction orientation in order to synthesize easily, the shape that is used for the powder B of synthetic anisotropy shape also should be preferably and be easy to when being shaped towards a direction orientation.

That is: still synthesize as reactive template under the situation of powders A of anisotropy shape at the powder B that uses the anisotropy shape, the average aspect ratio of the powders A of described anisotropy shape is preferably at least 3 or bigger, more preferably 5 or bigger, further more preferably 10 or bigger.Otherwise in order to prevent to break in the step of back, average aspect ratio is preferably 100 or littler.The preferred 1-20 μ of the median size m of the powder B of anisotropy shape, 1-13 μ m more preferably, further 2-8 μ m more preferably.

" reaction raw materials B " is meant that a kind of and powder B anisotropy shape reacts, generates the powders A of the anisotropy shape that comprises the represented compound of chemical formula (4) at least.In the case, reaction raw materials B can be the material that a kind of and the powder B anisotropy shape reacted, only generated the represented compound of chemical formula (2), perhaps generates the represented compound of chemical formula (2) and the material of remaining ingredient.Here used " remaining ingredient " is meant the material except the represented target compound of chemical formula (2).Powder B and reaction raw materials B in the anisotropy shape generate under the situation of remaining ingredient, and described remaining ingredient preferably comprises the easy material of removing with heat or chemical method.

For the form of reaction raw materials B, for instance, can use oxide powder, composite oxide power, such as the salt and the alkoxide of carbonate, nitrate and oxalate.In addition, can decide the composition of reaction raw materials B according to the composition of the composition of the represented compound that will generate of chemical formula (2) and anisotropy shape powder B.

For example, comprise the represented bismuth laminated perovskite type compd B i of chemical formula (3) in use _2.5Na _0.5Nb ₂O ₉The powder B (being designated hereinafter simply as " BINN2 ") of anisotropy shape come syntheticly when comprising the anisotropy shape powders A of the represented compound N N of chemical formula (2), can use the compound (as: oxide compound, oxyhydroxide, carbonate, nitrate) that contains Na as reaction raw materials B.In the case, can according to 1 mole of BINN2 add contain 1.5 moles of Na atoms contain the Na compound, with as reaction raw materials B.

When the suitable flux of 1-500wt% (for example, the mixture of NaCl, KCl and NaCl and KCl, BaCl2 or KF) join each self-contained above-mentioned composition the anisotropy shape powder B and second kind of reaction raw materials B and when being heated to the eutectic point fusing point, can generate NN and mainly by Bi ₂O ₃The remaining ingredient of forming.Bi ₂O ₃Fusing point low, resistance to acid also a little less than, therefore, when remove flux with methods such as hot washes and heating under the high temperature or with acid elution after, can obtain to comprise NN, orientation plane and be { the powders A of 100} planar anisotropy shape.

In addition, for instance, synthesize at the powder B of the anisotropy shape that comprises BINN2 by use and to contain the represented (K of chemical formula (2) _0.5Na _0.5) NbO ₃During the anisotropy shape powders A of (being designated hereinafter simply as " KNN "), can use compound (as: oxide compound, oxyhydroxide, carbonate and nitrate) that contains Na and the compound (as: oxide compound, oxyhydroxide, carbonate and nitrate) that contains K, or contain the compound of Na and K simultaneously, with as reaction raw materials B.In the case, can by 1 mole of BINN2 add the compounds containing sodium that contains 0.5 mole of Na atom, 1 mole of BINN2 add contain 1 mole of K atom contain the K compound, with as reaction raw materials B.

When the suitable flux of 1-500wt% joins the powder B and the reaction raw materials B of the anisotropy shape of each self-contained above-mentioned composition, and when being heated to the eutectic point fusing point, can generate KNN and mainly by Bi ₂O ₃Therefore the remaining ingredient of forming, is removing flux and Bi from the reaction product that obtains ₂O ₃After, can obtain to comprise KNN, orientation plane and be { the powders A of the anisotropy shape of 100}.

Same method can be applicable to by the powder B of anisotropy shape and reaction raw materials B reaction only generate by the represented compound of chemical formula (2), have the powder B of anisotropy shape of predetermined composition and the reaction raw materials B with predetermined composition and in suitable flux, heat, can in flux, generate thus have the target composition, by the represented compound of chemical formula (2).Remove flux from the reactant that obtains after, can obtain to comprise by chemical formula (4) represented compound and orientation plane is the powders A of the anisotropy shape of specific plane.

Lattice anisotropy by the represented compound of chemical formula (2) is little, therefore, is difficult to directly prepare the powders A of anisotropy shape, and also being difficult to directly preparation is the powders A of orientation planar anisotropy shape with artificial crystal face.

On the other hand, the lattice anisotropy of laminated perovskite type compound is big, therefore, directly synthesizes the powder of anisotropy shape easily.Simultaneously, in many cases, comprise laminated perovskite type compound anisotropy shape powder the orientation plane with by the particular crystal plane lattice match of the represented compound of chemical formula (2).And then, to compare with laminated perovskite type compound, the represented compound of chemical formula (2) is stablized on thermodynamics.

Therefore, when the powder B of the anisotropy shape that the particular crystal plane that comprises laminated perovskite type compound, orientation planar lattice and the represented compound of chemical formula (2) is complementary and reaction raw materials B react, the powder B of anisotropy shape can play the effect of reactive template, as a result, easily syntheticly comprise the represented compound of chemical formula (2) and be the powders A of the anisotropy shape of differently-oriented directivity with the powder B of anisotropy shape.

In addition, when the composition of the powder B of anisotropy shape and reaction raw materials B is optimized, A-position element (this element is hereinafter referred to as " residue A-position element ") contained among the powder B of anisotropy shape is discharged as remaining ingredient, simultaneously, generated the powders A that comprises the represented compound of chemical formula (2) and do not contain the anisotropy shape of residue A-position element.

Especially, when the powder B of anisotropy shape comprised the laminated perovskite type compound of the represented bismuth of chemical formula (3), Bi discharged as residual A position element, and generated mainly by Bi ₂O ₃The remaining ingredient of forming.Therefore, after this remaining ingredient is removed with heat or chemical method, can obtain to be substantially free of Bi, comprise by the represented compound of chemical formula (2), with the particular crystal plane is the powders A of orientation planar anisotropy shape.

For instance, to have with the pottery of target polycrystalline ceramic body, as by the powder of the represented isotropy perovskite-type compounds same composition of chemical formula (2) during as the ceramic coarse particle powder, can use with the ceramic coarse particle powder same composition is arranged, promptly the pottery with the target polycrystalline ceramic body has the powder of same composition as particulate powders.

For particulate powders, can react with the first anisotropy shape powder in the time of can using with ceramic coarse particle powder sintering, and can generate target polycrystalline ceramic body pottery as the represented compound of chemical formula (1).

In the case, particulate powders can perhaps can generate target pottery and remaining ingredient such as the isotropy perovskite-type compounds simultaneously by only generating the target pottery with the ceramic coarse particle powdered reaction as the isotropy perovskite-type compounds.When the reaction of ceramic coarse particle powder and particulate powders generated remaining ingredient, preferred remaining ingredient was to be easy to the material removed by heat or chemical method.

Like this, ceramic coarse particle powder and particulate powders are by different forming, and chemical reaction takes place in heat treatment step for the powder of anisotropy shape and particulate powders, can generate polycrystalline ceramic body thus, as the isotropy perovskite-type compounds.

Can be according to the composition of ceramic coarse particle powder and want the composition of the represented compound of the isotropy perovskite-type compounds that generates such as chemical formula (1) to decide the composition of particulate powders.The example that can be used as particulate powders comprises oxide powder, composite oxide power, hydroxide powder, such as the salt and the alkoxide of carbonate, nitrate and oxalate.

More specifically, for instance, when the powders A that contains the anisotropy shape of KNN or NN component in use prepares the crystal oriented ceramic that comprises by the represented isotropy perovskite-type compounds of chemical formula (1) as the ceramic coarse particle powder, can be achieved like this: will comprise Li, K, Na, Nb, the mixture of Ta and Sb element compound one of at least is as particulate powders, the powders A and the described particulate powders of anisotropy shape are blended to stoichiometric ratio, have the target composition so that it can generate, and by the represented isotropy perovskite-type compounds of chemical formula (1).

In further example, when the powder B that contains the anisotropy shape of the represented composition of chemical formula (3) in use prepares the crystal oriented ceramic that comprises as the represented isotropy perovskite-type compounds of chemical formula (1) as the ceramic coarse particle powder, can be achieved like this: will comprise Li, K, Na, Nb, the mixture of Ta and Sb element compound one of at least is as particulate powders, the powder B and the described particulate powders of anisotropy shape are blended to stoichiometric ratio so that its can generate have that target forms by the represented compound of chemical formula (1).Same method is applicable to that preparation contains the crystal oriented ceramic of other composition.

In mixing step, except that pressing the ceramic coarse particle powder and particulate powders of predetermined proportion fusion, also can add the amorphous fine powder that comprises a kind of compound, described compound and target pottery as the represented compound of chemical formula (1) by identical forming, can be by ceramic coarse particle powder and particulate powders being implemented sintering or reaction obtains (being " compound fine powder " to call this amorphous fine powder in the following text), and/or can add sintering aid such as CuO.The advantage that adds compound fine powder or sintering aid be can the acceleration of sintering body densification.

When fusion compound fine powder, if the blended ratio of compound fine powder is excessive, the shared blended ratio of ceramic coarse particle powder can reduce inevitably in the whole raw material, in the case, the orientation degree by particular crystal plane A in the polycrystalline ceramic body that uses the crystal oriented ceramic that the first anisotropy shape powder obtains as the ceramic coarse particle powder may reduce.Therefore, the best blended ratio of compound fine powder should as requested sintered density and orientation degree be carried out preferably.

Also have, when producing the represented isotropy perovskite-type compounds of chemical formula (1), the blended ratio of ceramic coarse particle powder is preferably set to and makes by ABO ₃In the compound of chemical formula (1) of expression, occupy the preferred 0.01-70at% of the ratio of one or more component elements in the ceramic coarse particle powder of A position, more preferably 0.1-50at%, further more preferably 1-10at%.Wherein " at% " refers to the ratio represented with atomic quantity per-cent.

The ceramic coarse particle powder and first particle powder and the compound fine powder that adds as required and the mixing of sintering aid can realize by dry process, or realize by the wet processing that adds suitable dispersion medium such as water or alcohol.At this moment, if necessary, also can further add caking agent and/or softening agent.

Forming step is described below:

Forming step is for by forming the step that produces molding to mixing the raw mix that obtains from ceramic coarse particle powder and particulate powders.

For instance, the manufacturing process that raw mix is shaped comprises scraping blade method, extrusion process, roll-in method, extrusion molding method and flospinning etc.

When containing the orientation planar first anisotropy shape powder and prepare the polycrystalline ceramic body that comprises with the crystal oriented ceramic of particular crystal plane A orientation as the ceramic coarse particle powder by use, can be achieved like this: in forming step, by being shaped, raw mix is prepared into body, the orientation plane is almost arranged, as previously described by equidirectional.

In the case, can be shaped, so that ceramic coarse particle powder (powder of the first anisotropy shape) carries out planar orientation or axle orientation by making raw mix.

The particularly preferred example that can make the ceramic coarse particle powder carry out the manufacturing process of planar orientation comprises scraping blade method, extrusion process and roll-in method.Also have, the particularly preferred example that can make the ceramic coarse particle powder carry out the manufacturing process of axle orientation comprises extrusion molding method and flospinning.

The ceramic coarse particle powder is the thickness or the raising orientation degree of the molding (to call " planar orientation molding " in the following text) of planar orientation in order to increase wherein, the planar orientation molding may need further processing, as stackedly press, extruding or roll-in etc. (to call " planar orientation processing " in the following text).

In the case, can use any planar orientation to the planar orientation molding and handle, but the planar orientation processing that also can use two or more.Further, can handle, perhaps repeatedly two or more planar orientations processing of repetitive administration separately a kind of planar orientation of planar orientation molding repetitive administration.

Heat treatment step is described below:

Heat treatment step makes molding shrink for being heated into body thus, and sintering ceramic coarse particle powder and particulate powders are to generate the step of polycrystalline ceramic body simultaneously.

In heat treatment step, molding is heated, and sintering is carried out as a result, can prepare the polycrystalline ceramic body such as the isotropy perovskite-type compounds that comprises as the required pottery of principal phase thus.At this moment, by ceramic coarse particle powder and particulate powders being carried out sintering or reacting and sintering, can prepare such as pottery by the represented compound of chemical formula (3).

In heat treatment step, depend on the powder of anisotropy shape and/or the composition of particulate powders, remaining ingredient produces simultaneously.

Heating temperature for heat treatment step, for example, the composition of the crystal oriented ceramic that can generate according to the composition or the expectation of ceramic coarse particle powder or particulate powders is selected optimum temps, reaction and/or sintering just can carry out effectively like this, and can generate the reaction product with target composition.

For example, have anisotropy shape powders A preparation that KNN forms when comprising with the represented compound of chemical formula (1) using as the polycrystalline ceramic body of the crystal oriented ceramic of principal phase, should make when implementing heating Heating temperature in the heating steps, the first maintenance process temperature T 1 (℃) in 1000≤T1≤1300 scopes.

In the time of in this temperature range, more excellent Heating temperature can be according to the represented compound of chemical formula (1), be that the composition of target substance decides.For warm-up time, can select the best time according to Heating temperature, so that the sintered density that can obtain requiring.

Further, when ceramic coarse particle powder and particulate powders reaction generation remaining ingredient, remaining ingredient is stayed in the sintered compact as parafacies (sub-phase), perhaps can from sintered compact, be removed remaining ingredient.For the situation of removing remaining ingredient, the example of method comprises, as described below, and hot removing method and chemical removal methods.

For instance, hot removing method is included in the method for evaporating remaining ingredient under the predetermined temperature by the heat-agglomerating body, and wherein said sintered compact contains the pottery and the remaining ingredient (hereinafter referred to as " intermediate sintering body ") of the requirement composition of the compound represented just like chemical formula (1).More specifically, preferable methods is under reduced pressure or in oxygen, long-time heating intermediate sintering body under the temperature that can cause the remaining ingredient evaporation.

Heating temperature when removing remaining ingredient for heat, the compound that pottery that can be as requested such as chemical formula (3) are represented and/or the composition of remaining ingredient are selected optimum temps, so that the evaporation of remaining ingredient can carry out effectively, and the generation of byproduct can be inhibited.

On the other hand, the example of the method for chemical scavenging remaining ingredient comprises the intermediate sintering body is immersed in the treatment soln of only corroding remaining ingredient, then the method for elimination remaining ingredient.For treatment soln as used herein, the compound that pottery that can be as requested such as chemical formula (3) are represented and/or the composition of remaining ingredient are selected optimum treatment soln.For example, when remaining ingredient is the bismuth oxide of single phase, can use acid such as nitric acid or hydrochloric acid as treatment soln.Especially, when the remaining ingredient that chemical extraction mainly is made up of bismuth oxide, nitric acid is suitable treatment soln.

The reaction of ceramic coarse particle powder and particulate powders and the removing of remaining ingredient can at any time be finished, and promptly can carry out synchronously, successively or individually.For example, by the temperature that the evaporation that molding is placed decompression down or vacuum, directly be heated the reaction that makes ceramic coarse particle powder and particulate powders and remaining ingredient can both effectively be carried out, the removing of remaining ingredient just can be carried out synchronously with reacting.

For example, also can be in air or oxygen effectively carry out and generate under the temperature of intermediate sintering body being heated into body in the reaction that can make ceramic coarse particle powder and particulate powders, then under reduced pressure or in the vacuum under the temperature that the evaporation that can make remaining ingredient is effectively carried out heating intermediate sintering body, perhaps by generating the intermediate sintering body, then in air or oxygen under the temperature that the evaporation that can make remaining ingredient is effectively carried out long-time heating intermediate sintering body, remove remaining ingredient.

This heat to remaining ingredient is removed and can for example carried out in the first maintenance process, the second maintenance process or the process of cooling.

In addition, for example can be by generating the intermediate sintering body, with intermediate sintering body cool to room temperature, then the intermediate sintering body is immersed in the treatment soln and come the chemical scavenging remaining ingredient, perhaps by generating the intermediate sintering body, with its cool to room temperature, in predetermined atmosphere, middle sintered compact is heated next heat once more then and remove remaining ingredient with predetermined temperature.

If in the molding that forming step obtains, contain caking agent, can before heat treatment step, be primarily aimed at the purpose thermal treatment of degreasing.In the case, skimming temp can be set at enough height, so that can make the caking agent thermolysis at least.

To the molding degreasing time, the orientation degree of ceramic coarse particle powder may reduce in the molding, or three-dimensional expansion may take place molding.In the case, before implementing heat treatment step, preferably the molding after the degreasing is implemented cold isostatic extrusion process (CIP).The orientation degree that this processing can avoid degreasing to cause reduces, or the sintered density that the three-dimensional expansion of molding causes reduces.

If ceramic coarse particle powder and particulate powders reaction have generated remaining ingredient and will remove remaining ingredient, then can be to carrying out the cold isostatic extrusion process, roasting again then from its intermediate sintering body of removing remaining ingredient.Equally, in order further to improve sintered density and orientation degree, can further carry out hot extrusion to sintered compact behind the heat treatment step.In addition, can be used in combination methods such as adding compound fine powder, CIP processing and hot extrusion.

In production method of the present invention, as mentioned above, also can by use help the powder B of anisotropy shape that synthetic comprises laminated perovskite type compound as reactive template, come the synthetic powders A that comprises the anisotropy shape of the represented compound of chemical formula (4), comprise the polycrystalline ceramic body of crystal oriented ceramic then as reactive template for preparing by the powders A of using described anisotropy shape.In the case, have little lattice anisotropy, also prepare the polycrystalline ceramic body that artificial high preferred orientation is wherein arranged easily at low cost even comprise the polycrystalline ceramic body of the represented compound of chemical formula (1) etc.

In addition, after the composition of the powder B of anisotropy shape and reaction raw materials B is optimized, even can synthesize the powders A of the anisotropy shape that does not contain residue A position element.Therefore, composition that can A very easy to control position element, and prepare a kind of its and form and be difficult to the polycrystalline ceramic body that comprises crystal oriented ceramic that obtains with ordinary method, wherein the principal phase of crystal oriented ceramic is by the represented compound of chemical formula (1).

Simultaneously, the above powder B that comprises the anisotropy shape of laminated perovskite type compound can be used as the ceramic coarse particle powder.In the case, by the sintering in heat treatment step, can synthesize the pottery of the crystalline orientation that comprises represented compound of chemical formula (1) etc. simultaneously.Further, when the composition of the composition of the anisotropy shape powder B that will be orientated in molding and the particulate powders that will react with it is optimized, not only can synthesize such as target pottery, can also discharge residue A position element from the powder B of anisotropy shape as remaining ingredient by the represented compound of chemical formula (1).

In addition, the powder B of the anisotropy shape that is easy to remove with heat or chemical method when use, generate remaining ingredient is during as the ceramic coarse particle powder, can obtain a kind ofly to be substantially free of residue A position element, comprises the represented compound of chemical formula (1) etc., with the crystal oriented ceramic of particular crystal plane orientation.

As mentioned above, can prepare in the present invention that to comprise as the isotropy perovskite-type compounds be the polycrystalline ceramic body of principal phase.The example that constitutes the isotropy perovskite-type compounds of polycrystalline ceramic body comprises that a kind of basic components is potassium-sodium niobate (K _1-yNa _y) NbO ₃Compound, wherein the Li of A position element part (K and Na) scheduled amount replaces, and/or B position element partly the Ta and/or the Sb of (Nb) scheduled amount replace.

It is principal phase that polycrystalline ceramic body preferably comprises the represented isotropy perovskite-type compounds of following chemical formula (1): { Li _x(K _1-yNa _y) _1-x(Nb _1-z-wTazSb _w) O ₃(wherein: 0≤x≤0.2,0≤y≤1,0≤z≤0.4,0≤w≤0.2 and x+z+w＞0) (claim 14).

In the case, the piezoelectric property of polycrystalline ceramic body, dielectric properties and temperature performance can further improve.

In chemical formula (1), the implication of " x+z+w＞0 " is that it is just enough to contain a kind of at least element of Ti, Ta and Sb in the substituted element.

In chemical formula (1), y represents the ratio of K and Na in the isotropy perovskite-type compounds.In isotropic perovskite-type compounds, A position element comprises K and Na at least, and one of them is just enough.

In chemical formula (1), the preferable range of y is 0＜y≤1.

In the case, y is the basal component in the represented compound of chemical formula (1).Correspondingly, the piezoelectric property of polycrystalline ceramic body such as piezoelectric constant g ₃₁Can further be promoted.In addition, along with increasing of the amount that adds K, molding can be at lower sintering temperature, therefore, can be more energy-conservation when producing polycrystal, cost is also lower.

In chemical formula (1), y is 0.05≤y≤0.75 more preferably, further 0.20≤y≤0.70 more preferably.In these cases, the piezoelectric constant d of crystal oriented ceramic ₃₁Can further be promoted with electromechanical coupling factor Kp.Further, preferred 0.20≤y＜0.70, more preferably 0.35≤y≤0.65, further more preferably 0.35≤y＜0.65, most preferably 0.42≤y0.60.

" x " expression replaces the replacement amount of the Li of A position element K and/or Na.When Partial K and/or Na are replaced by Li, can produce such as improving performance such as piezoelectric property, improve Curie-point temperature and/or quickening effects such as densification.

In chemical formula (1), the scope of x is preferably 0＜x≤0.2.

In the case, Li is the basal component in the represented compound of chemical formula (1).Correspondingly, easier the carrying out of roasting during not only polycrystalline ceramic body prepares, piezoelectric property also more can improve, and Curie temperature (Tc) also can be higher.This be because, when contained Li as basal component was in above-mentioned x scope, maturing temperature was reduced, simultaneously Li as ignition dope can make in the roasting room (vacancy) still less.

When the value of x surpasses 0.2, piezoelectric property (as: piezoelectric constant d ₃₁, electromechanical coupling factor Kp, piezoelectric constant g ₃₁) can variation.

Simultaneously, in the chemical formula (1), the x value can be x=0.

In the case, chemical formula (1) is expressed as (K _1-yNa _y) (Nb _1-z-wTazSb _w) O ₃, owing to do not comprise compound such as the LiCO that contains the lightest Li of weight in the raw materials for production of polycrystalline ceramic body ₃So, mixing by raw material when producing crystal oriented ceramic, can reduce because of raw material powder and separate caused performance inconsistency.And, in the case, can realize high specific inductivity and relatively large piezoelectric constant g.

In chemical formula (1), the x value is 0≤x≤0.15 more preferably, further 0≤x≤0.10 more preferably.

" z " expression replaces the replacement amount of the Ta of B position element nb.When part Nb is replaced by Ta, can produce such as the effect of suppressing liftings such as electrical property.In chemical formula (3), if the value of z surpasses 0.4, Curie-point temperature can descend, thereby is difficult to be applied on household electrical appliance or automobile as piezoelectric.

In chemical formula (1), the scope of z is preferably 0＜z≤0.4.

In the case, Ta is the basal component in the represented compound of chemical formula (1).Correspondingly, the sintering temperature step-down, Ta can make the room in the polycrystalline ceramic body tail off as sintering aid simultaneously.

Simultaneously, in the chemical formula (1), the z value can be z=0.

In the case, chemical formula (1) can be expressed as { Li _x(K _1-yNa _y) _1-x(Nb _1-wSb _w) O ₃, owing to do not contain Ta in the represented compound of chemical formula (1), so do not use expensive Ta component in producing, polycrystalline ceramic body also can show outstanding piezoelectric property.

In chemical formula (1), the z value is 0≤z≤0.35 more preferably, further 0≤z≤0.30 more preferably.

" w " expression replaces the replacement amount of the Sb of B position element nb.When part Nb is replaced by Sb, can produce effect such as piezoelectric property lifting etc.If the value of w surpasses 0.2, piezoelectric property and/or Curie-point temperature will descend, so this should not pay the utmost attention to.

In chemical formula (1), the scope of w is preferably 0＜w≤0.2.

In the case, Sb is the basal component in the represented compound of chemical formula (1), therefore, polycrystalline ceramic body sintering temperature step-down not only, sinterability is enhanced, but also can improve the stability of dielectric loss tan δ.

Simultaneously, in the chemical formula (1), the w value can be z=0.

In the case, chemical formula (1) can be expressed as { Li _x(K _1-yNa _y) _1-x(Nb _1-zTa _z) O ₃, owing to do not contain Sb in the represented compound of chemical formula (1), so polycrystalline ceramic body can show higher relatively Curie-point temperature.

In chemical formula (1), the w value is 0≤w≤0.15 more preferably, further 0≤w≤0.10 more preferably.

Polycrystalline ceramic body preferably only comprises by the represented isotropy perovskite-type compounds of chemical formula (1), as long as but can keep the crystalline structure of isotropy perovskite typed, and various performances such as sintering character and piezoelectric property do not affect adversely, and polycrystalline ceramic body just can comprise other element or other phase.

Polycrystalline ceramic body preferably contains one or more other elements of the represented isotropy perovskite-type compounds 0.0001-0.15 mole of every mole of chemical formula (1), and these elements are selected from (claims 15) such as metal, semi-metal, transition metal, precious metal and alkaline-earth metal that belongs to periodic table of elements 2-15 family.

In the case, can further improve piezoelectric property (as: the piezoelectric constant d of polycrystalline ceramic body ₃₁, electromechanical coupling factor Kp, piezoelectric constant g ₃₁), relative permittivity and dielectric loss etc.In polycrystalline ceramic body, other element can join in the represented compound of chemical formula (1) by displacement, perhaps can add from the outside and be present in the particle, or be present on the represented compound of chemical formula (1) crystal grain on every side.Also have, other element also can be used as extra single-element or as the oxide compound that contains described other element or compound and in conjunction with entering.

If the amount of other element is lower than 0.0001, the adding of element may not obtain the effect of gratifying raising piezoelectric property, and if above 0.15 mole, the piezoelectric property of polycrystalline ceramic body or dielectric properties are variation on the contrary.

The specific examples of other element comprises Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Hf, W, Re, Pd, Ag, Ru, Rh, Pt, Au, Ir, Og, B, Al, Ga, In, Si, Ge, Sn and Bi etc.

By to compound { Li represented in the following chemical formula (1) _x(K _1-yNa _y) _1-x(Nb _1-z-wTa _zSb _w) O ₃One or more elements that are selected from Li, K, Na, Nb, Ta and Sb in (wherein: 0≤x0.2,0≤y≤1,0≤z≤0.4,0≤w≤0.2 and x+z+w＞0) are replaced, and preferably the ratio with 0.01-15at% adds other element.

In the case, can further improve piezoelectric property (as: the piezoelectric constant d of polycrystalline ceramic body ₃₁, electromechanical coupling factor Kp) and dielectric properties (as: relative permittivity ε _33T/ ε ₀).

If other element ratio that adds by displacement is lower than 0.01at%, may not obtain the effect of gratifying raising polycrystalline ceramic body piezoelectric property or dielectric properties so, if and above 15at%, the piezoelectric property of polycrystalline ceramic body or dielectric properties are variation on the contrary.The ratio of other element that adds by displacement is preferably 0.01-5at%, 0.01-2at% more preferably, further 0.05-2at% more preferably.

" at% " is meant the ratio that Li, K, Na, Nb, Ta and Sb atomic quantity are represented with per-cent in the represented compound of substitutional atom quantity and chemical formula (1).

Embodiment

Embodiment 1

Embodiments of the invention are below described.

This embodiment is the example of preparation polycrystalline ceramic body.

In the preparation method of the polycrystalline ceramic body of present embodiment, implement preparation process, mixing step, forming step and heat treatment step etc.

In preparation process, the preparation median size is the ceramic coarse particle powder of 1-20 μ m and 1/3 or the littler particulate powders that median size is ceramic coarse particle powder median size, and this particulate powders generates polycrystalline ceramic body during with ceramic coarse particle powder sintering.

In mixing step, ceramic coarse particle powder and particulate powders are mixed to produce raw mix.In forming step, raw mix is shaped and the generation powder agglomates.Heat powder agglomates in heat treatment step, thereby this powder agglomates shrinks, simultaneously, sintering ceramic coarse particle powder and particulate powders are to produce polycrystalline ceramic body.

In heat treatment step, implement the temperature-rise period and the first maintenance process, and then also implement second maintenance process and/or the process of cooling.

In temperature-rise period, begin powder agglomates is heated to heat up.In the first maintenance process, powder agglomates kept 0.1 minute or longer down in 1 ℃ of temperature T (condition is 600≤T1≤1,500).

Equally, in the second maintenance process, powder agglomates kept 10 minutes or longer down in 2 ℃ of the temperature T that is lower than 1 ℃ of temperature T (wherein T2 〉=300).In process of cooling, powder agglomates cools off with 60 ℃/h or lower rate of temperature fall from 1 ℃ of beginning of temperature T.

In the present embodiment, the polycrystalline ceramic body of preparation is the polycrystalline ceramic body that comprises crystal oriented ceramic, and the particular crystal plane that wherein constitutes the crystal grain of polycrystalline ceramic body is oriented.Especially, the polycrystalline ceramic body for preparing among this embodiment comprises the serve as reasons crystal oriented ceramic of the represented isotropic perovskite-type compounds of following chemical formula (1) of principal phase: { Li _x(K _1-yNa _y) _1-x(Nb _1-z-wTa _zSb _w) O ₃(wherein: 0≤x≤0.2,0≤y≤1,0≤z≤0.4,0≤w≤0.2 and x+z+w＞0).

In the present embodiment, having prepared a plurality of comprising by the represented crystal oriented ceramic of chemical formula (1) and by different forms and the polycrystalline ceramic body of working condition.

Details are as follows for the production method of present embodiment polycrystalline ceramic body:

In the present embodiment, the principal phase that has prepared a kind of wherein crystal oriented ceramic is the polycrystalline ceramic body with isotropy perovskite-type compounds of following chemical formula (1) composition, wherein: x=0.08, y=0.5, z=0.1 and w=0.06 specifically, have prepared a kind of { Li that is expressed as _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The isotropy perovskite-type compounds.

(1) preparation of ceramic coarse particle powder

At first, preparation is as the first anisotropy shape powder of ceramic coarse particle powder by the following method, this powder comprises the orientation planar first orientation particle that forms by the particular crystal plane orientation, and this orientation plane has the lattice that is complementary with the particular crystal plane A that constitutes the target polycrystalline ceramic body.More specifically, in the present embodiment, prepared and comprised Bi _2.5Na _3.5Nb ₅O ₁₈The powder B of anisotropy shape, comprise NaNbO by using the powder B of this anisotropy shape, having prepared ₃The powder (powders A of anisotropy shape) of the first tabular anisotropy shape.

That is, with Bi ₂O ₃Powder, Na ₂CO ₃Powder and Nb ₂O ₅Powder is weighed by stoichiometric ratio, to obtain Bi _2.5Na _3.5Nb ₅O ₁₈Composition (following be called sometimes " BINN5 "), these powder are carried out wet mixing.Subsequently, the NaCl that adds 50wt% does the raw material that obtains mixed 1 hour as flux.

Pour the mixture that obtains into platinum alloy crucible, heated 1 hour down, after flux melts fully, continue heating 2 hours down, synthetic thus BINN5 at 1100 ℃ at 850 ℃.At this, temperature rise rate is 200 ℃/h, and cooling is cooled off by stove and realized.After the cooling, flux is removed from reaction product, obtained the BINN5 powder by hot wash.The BINN5 powder that obtains is that the orientation plane is { the tabular powder of 001} planar.

After this, with Na ₂CO ₃Powder (reaction raw materials) is with synthetic NaNbO ₃(following be called sometimes " NN ") required amount joins in the tabular powder that comprises BINN5, with these powder mixes, is flux thermal treatment 8 hours in platinum alloy crucible under 950 ℃ temperature then with NaCl.

In the reaction product that obtains, except NaNbO ₃Powder also contains Bi outward ₂O ₃Therefore, after therefrom removing flux, reaction product is immersed HNO ₃The aqueous solution in, to dissolve the remaining ingredient Bi of generation ₂O ₃And then, the solution that obtains is filtered to isolate NN, under 80 ℃, wash then with ion exchanged water.Like this, obtained to be used as the NN powder (powders A of anisotropy shape) of ceramic coarse particle powder.This powder is labeled as powdered sample A1.

The NaNbO that obtains ₃Powder is tabular powder, and its median size is 15 μ m, and aspect ratio is about 10-20, and the orientation plane is pseudo-cube { 100} plane.

(2) preparation of particulate powders

Next, prepare particulate powders by the following method, the median size of this particulate powders be ceramic coarse particle powder median size 1/3 or littler, when it can generate polycrystalline ceramic body during with ceramic coarse particle powder sintering.

In the present embodiment, as hereinafter described, fusion NN powder is so that at chemical formula ABO ₃Composition { the Li of represented target pottery _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The A position elements of middle 5at% is the element in NN powder (ceramic coarse particle powder) usually.

In the preparation of particulate powders, respectively be 99.99% or higher Na with purity ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅The powder fusion, resulting consisting of from the target pottery formed { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃In deduct the fusion part of NN powder and the composition that obtains, be that medium uses ZrO with the organic solvent ₂Ball was with these powder wet mixings 20 hours.

Then, the mixed powder that obtains being descended interim roastings 5 hours for 750 ℃ in temperature, further is that medium uses ZrO again with the organic solvent ₂Ball wet-milling 20 hours, can get median size thus is the interim powders calcined (particulate powders) of about 0.5 μ m.This powder is labeled as powdered sample B1.

(3) preparation of powder agglomates

Then, use the ceramic coarse particle powder (powdered sample A1) and the particulate powders (powdered sample B1) of above preparation to prepare polycrystalline ceramic body, this polycrystalline ceramic body comprises the pottery of crystalline orientation, and its principal phase is can be by { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The isotropy perovskite-type compounds of expression.

That is, powdered sample A1 and powdered sample B1 are weighed to obtain { Li by stoichiometric ratio _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃Target form, be medium with the organic solvent, use ZrO ₂Ball wet mixing 20 hours obtains the raw mix slurries.

Add in these slurries again that polyvinyl alcohol as caking agent contracts that fourth contracts (PVB) and as the dibutyl phthalate of softening agent, every kind of add-on respectively be about 10.35 gram/mole targets composition { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃, mixed subsequently 2 hours.

After having mixed caking agent and softening agent, the raw mix slurries are configured as the tape (tape) that thickness is about 100 μ m with squeegee devices, these tapes are stacked, through excess pressure combination and roll-in and obtain the thick tabular powder agglomates of 1.5mm.Tabular powder agglomates degreasing to obtaining then.Carry out in the degreasing air under the following conditions: Heating temperature is 600 ℃, and be 5 hours heat-up time, and temperature rise rate is 50 ℃/h, and rate of cooling is the stove cooling.Further making tabular powder agglomates is being to stand CIP under the 300Mpa to handle at pressure after the degreasing.The powder agglomates that obtains thus is labeled as shaping sample D1.

(4) roasting

Then, by being carried out roasting, the above powder agglomates that obtains (shaping sample D1) prepares polycrystalline ceramic body.When forming sample D1 roasting, implement temperature-rise period, first maintenance process and the process of cooling.

Promptly, after shaping sample D1 put into process furnace, temperature rise rate with 200 ℃/h rises to 1100 ℃ of temperature (temperature-rise period) with temperature, and sample is kept 1 hour (the first maintenance process) down for 1100 ℃ in temperature, and the rate of temperature fall with 5 ℃/h is cooled to 1000 ℃ (process of cooling) with it then.Further, it is cooled to room temperature, takes out polycrystalline ceramic body then with the rate of temperature fall of 200 ℃/h.

Like this, just obtain comprising principal phase and be { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body of crystal oriented ceramic.This polycrystalline ceramic body is labeled as sample E1.

In the present embodiment, change roasting condition into sample E1 different, other preparation method is the same with the maintenance of sample E1, thereby prepares a plurality of polycrystalline ceramic bodies that have with the E1 same composition, and these identified as samples are designated as sample E2 to sample E4.More specifically, prepare above-mentioned shaping sample D1 by the same way as for preparing above sample E1, roasting shaping sample D1 prepares sample E2 thus to sample E4 under the following conditions.

More specifically, when preparation sample E2, D1 puts into process furnace with the shaping sample, and temperature is risen to 1100 ℃ (temperature-rise periods).In this section the period, temperature rise rate with 200 ℃/h rises to 825 ℃ with temperature, temperature rise rate with 115 ℃/h rises to 990 ℃ with temperature, continuation rises to 1100 ℃ with the temperature rise rate of 25 ℃/h with temperature, simultaneously, in temperature-rise period, control temperature rise rate, so that the contraction of shaping sample D1 to be about 0.0005%/second or lower linear shrinkage (obtaining the contraction factor of constant rate of speed like this in the temperature range that sintering is taken place) takes place.

Thereafter, the same mode is implemented first maintenance process and the process of cooling according to production sample E1 the time, prepares thus to comprise the polycrystalline ceramic body (sample E2) that the crystal oriented ceramic of same composition is arranged with sample E1.

When production sample E3, D1 puts into process furnace with the shaping sample, and E2 is similar with sample, with the temperature rise rate of 200 ℃/h temperature is risen to 825 ℃, temperature rise rate with 115 ℃/h rises to 990 ℃ with temperature, continues with the temperature rise rate of 25 ℃/h temperature to be risen to 1100 ℃.Simultaneously, in temperature-rise period, should control temperature rise rate, so that the contraction of shaping sample D1 is to be about 0.0005%/second or lower linear shrinkage capable (obtaining the contraction factor of constant rate of speed like this in the temperature range that sintering is taken place).Thereafter, the same way as according to production sample E1 the time keeps 1 hour down to finish the first maintenance process with sample 1100 ℃ of temperature, makes sample be cooled to 1000 ℃ (process of cooling) with the rate of temperature fall of 10 ℃/h then.Further,, sample is cooled to room temperature, prepares thus and comprise the polycrystalline ceramic body (sample E3) that the crystal oriented ceramic of same composition is arranged with sample E1 with the rate of temperature fall of 200 ℃/h according to the mode the same with sample E1.

When production sample E4, D1 puts into process furnace with the shaping sample, and E2 is similar with sample, with the temperature rise rate of 200 ℃/h temperature is risen to 825 ℃, temperature rise rate with 115 ℃/h rises to 990 ℃ with temperature, continues with the temperature rise rate of 25 ℃/h temperature to be risen to 1100 ℃.Simultaneously, in temperature-rise period, control temperature rise rate, so that (obtaining the contraction factor of constant rate of speed like this in the temperature range that sintering is taken place) carried out in the contraction of shaping sample D1 to be about 0.0005%/second or lower linear shrinkage.Thereafter, the same way as according to production sample E1 the time keeps 1 hour down to finish the first maintenance process with sample at 1100 ℃, and then, sample is cooled to 1000 ℃ (process of cooling) with the rate of temperature fall of 20 ℃/h.Further, according to the mode the same with sample E1, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, prepares thus to comprise the polycrystalline ceramic body (sample E4) that the crystal oriented ceramic of same composition is arranged with sample E1.

In the present embodiment, in order to compare, only use median size to prepare the polycrystalline ceramic body that same composition is arranged with sample E1 to E4 for the interim powders calcined of about 0.5 μ m with sample E1 to E4.This polycrystalline ceramic body is labeled as sample C1.During preparation sample C1, the ceramic coarse particle powder that uses as template when not using preparation sample E1 to E4, sample C1 is non-orientation body.

In the preparation of sample C1, preparation purity respectively is 99.99% or higher Na ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder.These powder are weighed by stoichiometric ratio, obtain { Li thus _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃Composition, be that medium uses ZrO with the organic solvent ₂Ball wet mixing 20 hours.Then, the blended powder that obtains further is medium ZrO with the organic solvent 750 ℃ of following interim roastings of temperature 5 hours again ₂Ball wet-milling 20 hours, can get median size thus is the interim powders calcined of about 0.5 μ m.This powder is labeled as powdered sample B2.

Then, be that medium uses ZrO with the organic solvent ₂Ball with powdered sample B2 wet mixing 20 hours, obtains slurries.

After this, according to preparation sample E1 identical mode, in slurries, add caking agent and softening agent, with squeegee devices slurries are shaped, the powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm through excess pressure combination and roll-in.And then, according to preparation sample E1 identical mode, make this powder agglomates degreasing and the CIP that stands subsequently handles.The powder agglomates that obtains thus is labeled as shaping sample D2.

Then, shaping sample D2 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1100 ℃, sample kept 1 hour down for 1100 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature with it, took out polycrystalline ceramic body.Like this, just having obtained comprising can be by { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body (sample C1) of the non-orientation ceramic of expression.

Equally, in the present embodiment,, except roasting condition changes the preparation that is different from these samples into, prepare in the same way and comprise the polycrystalline ceramic body that the crystal oriented ceramic of same composition is arranged with sample E1 to E4 in order to compare with sample E1 to E4.This polycrystalline ceramic body is labeled as sample C2.More specifically, prepare shaping sample D1 according to the mode identical with preparation sample E1, roasting shaping sample D1 under the following conditions, thus prepare sample C2.

That is, after with the same way as of preparation sample E1 shaping sample D1 being put into process furnace, with the temperature rise rate of 200 ℃/h temperature is risen to 1100 ℃, sample kept 1 hour down for 1100 ℃ in temperature.After this, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.Like this, just obtain comprising principal phase and be { Li _0.08(K _0.5Na _0.5) _0.92(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body (sample C2) of crystal oriented ceramic.

Shown in the table 1 for the composition of the sample E1 to E4 for preparing thus and sample C 1 and C2, whether be orientated, the amount and the roasting condition of NN powder template.Mention that at will in the table of mentioning 2 and table 3, the amount of NN powder template is meant at chemical formula ABO after table 1 reaches ₃During forming, the target pottery of expression offers the amount (at%) of A position element.

Table 1

Sample number	Form				Whether be orientated	NaNbO 3The amount of template (at%)	The intensification condition	The top temperature condition		The cooling condition
											x	y	z	W	Temperature (℃)	Time (h)
	Sample E1	0.08 ?	0.50 ?	0.10 ?				0.06 ?	Orientation								5 ?	200℃/h ?	1100 ?	1 ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
Sample E2					? 0.08 ? ?	? 0.50 ? ?	? 0.10 ? ?			? 0.06 ? ?	Orientation	? 5 ? ?	200 ℃/h (to 825 ℃) → 115 ℃/h (to 990 ℃) → 25 ℃/h (to 1100 ℃)	? 1100 ? ?	? 1 ? ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
	Sample E3	? 0.08 ? ?	? 0.50 ? ?	? 0.10 ? ?				? 0.06 ? ?	Orientation								? 5 ? ?	200 ℃/h (to 825 ℃) → 115 ℃/h (to 990 ℃) → 25 ℃/h (to 1100 ℃)	? 1100 ? ?	? 1 ? ?	10 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
Sample E4					? 0.08 ? ?	? 0.50 ? ?	? 0.10 ? ?			? 0.06 ? ?	Orientation	? 5 ? ?	200 ℃/h (to 825 ℃) → 115 ℃/h (to 990 ℃) → 25 ℃/h (to 1100 ℃)	? 1100 ? ?	? 1 ? ?	20 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
	Sample C1	0.08	0.50	0.10				0.06	Non-orientation								0	200℃/h	1100	1	200℃/h
Sample C2					0.08	0.50	0.10			0.06	Orientation	5	200℃/h	1100	1	200℃/h

Embodiment 2

Present embodiment has the example of the polycrystalline ceramic body of different compositions for preparation and the polycrystalline ceramic body of embodiment 1.In the present embodiment, prepared the polycrystalline ceramic body (sample E5) that comprises crystal oriented ceramic, the principal phase of this crystal oriented ceramic is for having the isotropy perovskite-type compounds that chemical formula (1) is formed, wherein: x=0.04, y=0.54, Z=0.1 and w=0.06, that is, by { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Isotropic perovskite-type compounds of expression.

In the preparation of sample E5, at first,, grind with the powder B of dry grinding then this anisotropy shape according to preparing the powder B (BINN5) of anisotropy shape with the same way as of embodiment 1.

Then, the powder of the anisotropy shape after use grinding is prepared powders A (NN powder) as the anisotropy shape of ceramic coarse particle powder according to the mode identical with embodiment 1.This powder is labeled as powdered sample A2.

Powdered sample A2 is tabular powder, and its median size is 6 μ m, and aspect ratio is about 4-10, and the orientation plane is pseudo-cube { 100} plane.

After this, produce particulate powders according to the mode identical with embodiment 1.This powder is labeled as powdered sample B3.

Prepare powdered sample B3 according to the mode identical, except with Na with powdered sample B1 among the embodiment 1 ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes and the target pottery that obtains consist of { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Powdered sample B3 is that median size is the interim powders calcined (particulate powders) of about 0.5 μ m.

Then, similar to Example 1, powdered sample A2 and powdered sample B3 are weighed by stoichiometric ratio, obtain following target thus and form { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃, and form slurries, make this slurries shaping also generate a kind of powder agglomates (molding) after the degreasing.The implementation process of the preparation of slurries, shaping and degreasing is identical with the mode of embodiment 1.The powder agglomates that obtains thus is labeled as shaping sample D3.

After shaping sample D3 put into process furnace, temperature rise rate with 200 ℃/h rises to 1125 ℃ (temperature-rise periods) with temperature, sample is kept 1 hour (the first maintenance process) down for 1125 ℃ in this temperature, and the rate of temperature fall with 5 ℃/h is cooled to 1000 ℃ of temperature (process of cooling) then.Further, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.

Like this, just obtained polycrystalline ceramic body (sample E5), this polycrystalline ceramic body comprises principal phase and is { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Crystal oriented ceramic.

In the present embodiment, change roasting condition into sample E5 different, other preparation method is the same with the maintenance of sample E5, prepares the polycrystalline ceramic body that same composition is arranged with sample E5 thus.This polycrystalline ceramic body is labeled as sample E6.More specifically, prepare above-mentioned shaping sample D3 with the same way as of preparation E5, and roasting shaping sample D3 under the following conditions, thereby prepare sample E6.

That is, the shaping sample D3 that obtains is put into process furnace, elevated temperature to 1125 ℃.In this section the period, with the temperature rise rate of 200 ℃/h temperature is risen to 920 ℃, with the temperature rise rate of 65 ℃/h temperature is risen to 1040 ℃, continue temperature to be risen to 1125 ℃ with the temperature rise rate of 12 ℃/h.Simultaneously, control intensification speed in temperature-rise period is so that (obtaining the contraction factor of constant rate of speed like this in the temperature range that sintering is taken place) takes place to be about 0.0005%/second or lower linear shrinkage in the contraction of shaping sample D3.

After this, the same way as according to preparation sample E5 the time is finished first maintenance process and the process of cooling, is cooled to room temperature then, thus, has prepared and comprises the polycrystalline ceramic body (sample E6) that the crystal oriented ceramic of same composition is arranged with sample E5.

Equally, in the present embodiment,, only use median size to prepare the polycrystalline ceramic body that same composition is arranged with sample E5 and E6 for the interim powders calcined of about 0.5 μ m in order to compare with sample E5 and E6.This polycrystalline ceramic body is labeled as sample C3.During preparation sample C3, owing to use the ceramic coarse particle powder that uses as template when preparing sample E5 to E6, so sample C3 is non-orientation body.

That is, in the preparation of sample C3, according to embodiment 1 in the same way as of preparation sample C1 at first prepare interim powders calcined.This roasting powder is labeled as powdered sample B4.The mode of preparation powdered sample B4 is with to prepare powdered sample B2 identical, except respectively being 99.99% or higher Na with purity ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes by stoichiometric ratio, resulting target pottery consist of { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Powdered sample B4 is the interim powders calcined of the about 0.5 μ m of median size.

Further, according to the same way as of preparation sample C1, B4 prepares slurries with powdered sample, adds caking agent and softening agent and mix in slurries, makes the slurries shaping with squeegee devices again.The powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm, make this powder agglomates degreasing and the CIP that stands subsequently handles through excess pressure combination and roll-in.The powder agglomates that obtains thus is labeled as shaping sample D4.

Then, shaping sample D4 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1125 ℃, sample was kept 1 hour down for 1125 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature, take out polycrystalline ceramic body.Like this, just having obtained comprising can be by { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body (sample C3) of the non-orientation ceramic of expression.

Equally, in the present embodiment,, except roasting condition changes the preparation that is different from these samples into, prepare in the same way and comprise the polycrystalline ceramic body that the crystal oriented ceramic of same composition is arranged with E5 and E6 in order to compare with sample E5 and E6.This polycrystalline ceramic body is labeled as sample C4.More specifically, the same way as during with preparation E5 and E6 prepares shaping sample D3, roasting shaping sample D3 under the following conditions, thus prepare sample C4.

That is, with the same way as of preparation sample E5, D3 puts into process furnace with the shaping sample, with the temperature rise rate of 200 ℃/h temperature is risen to 1125 ℃, and sample was kept 1 hour down for 1125 ℃ in temperature.After this, it is cooled to room temperature, takes out polycrystalline ceramic body then with the rate of temperature fall of 200 ℃/h.Like this, just obtained comprising with { Li _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Polycrystalline ceramic body (sample C4) for the crystal oriented ceramic of principal phase.

Shown in the following table 2 for the sample E5 and the composition of E6 and sample C3 and C4 of preparation thus, whether be orientated, the amount of NN powder template and roasting condition etc.

Further, in the present embodiment, prepared the polycrystalline ceramic body (sample E7) that comprises crystal oriented ceramic, the principal phase of this crystal oriented ceramic is the isotropy perovskite-type compounds with composition of chemical formula (1), wherein x=0.04, y=0.5, z=0.1 and w=0.04, that is be to be expressed as { Li, _0.04(K _0.46Na _0.54) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Isotropic perovskite-type compounds.

In the preparation of sample E7, at first prepare the ceramic coarse particle powder (powders A of anisotropy shape; The NN powder).With regard to the ceramic coarse particle powder, the preparation with embodiment 1 in the identical powder of powdered sample A1.

Then, according to embodiment 1 in same way as prepare particulate powders.This powder is labeled as powdered sample B5.

According to embodiment 1 in the same way as of powdered sample B1 prepare powdered sample B5, except with Na ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes the composition { Li that obtains following target pottery by stoichiometric ratio _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Powdered sample B5 is the interim powders calcined (particulate powders) of the about 0.5 μ m of median size.

Then, similar to Example 1, by stoichiometric ratio weigh powdered sample A1 and powdered sample B5, obtain target and form { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃, and form slurries, these slurries are shaped also generate powder agglomates after the degreasing.The implementation process of the preparation of slurries, shaping and degreasing is identical with the mode of embodiment 1.The powder agglomates that obtains thus is labeled as shaping sample D5.

Then, the shaping sample D5 that obtains is put into process furnace, temperature is risen to 1125 ℃ (temperature-rise periods).In this section the period, with the temperature rise rate of 200 ℃/h temperature is risen to 955 ℃, with the temperature rise rate of 46 ℃/h temperature is risen to 1069 ℃, continue temperature to be risen to 1125 ℃ with the temperature rise rate of 9 ℃/h.Simultaneously, in temperature-rise period, control temperature rise rate, so that the contraction of shaping sample D1 is to be about 0.0005%/second or lower linear shrinkage generation.Further, the powder agglomates (shaping sample D5) that causes because of being heated shrinks and almost takes place with constant linear shrinkage speed, its temperature range be from temperature than top temperature T1 (1115) ℃ low 50 ℃ to T1 ℃, in the present embodiment, temperature range is 1069 ℃-1115 ℃.Therefore, sample is kept 1 hour (the first maintenance process) down for 1115 ℃ in temperature, the rate of temperature fall with 5 ℃/h is cooled to 1000 ℃ (process of cooling) then.Further, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.

Like this, just obtained polycrystalline ceramic body (sample E7), this polycrystalline ceramic body comprises principal phase and is { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Crystal oriented ceramic.

In the present embodiment, in order to compare, only use median size to prepare the polycrystalline ceramic body that same composition is arranged with sample E7 for the interim powders calcined of about 0.5 μ m with sample E7.This polycrystalline ceramic body is labeled as sample C5.The ceramic coarse particle powder that uses as template when not using preparation sample E7 during preparation sample C5 is so sample C5 is non-orientation body.

That is, in the preparation of sample C5, according to embodiment 1 in the same way as of preparation sample C1, at first prepare interim powders calcined.This roasting powder is labeled as powdered sample B6.The mode of producing powdered sample B6 is identical with powdered sample B2's, except respectively being 99.99% or higher Na with purity ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes by stoichiometric ratio, and obtains { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃Target pottery form.Powdered sample B6 is the interim powders calcined of the about 0.5 μ m of median size.

Further, according to preparation sample C1 identical mode, B6 prepares slurries with powdered sample, adds caking agent and softening agent and mix in slurries, makes the slurries shaping with squeegee devices.The powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm, make this powder agglomates degreasing and the CIP that stands subsequently handles through excess pressure combination and roll-in.The powder agglomates that obtains thus is labeled as shaping sample D6.

Then, shaping sample D6 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1115 ℃, sample kept 1 hour down for 1115 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature with it, took out polycrystalline ceramic body.Like this, just having obtained comprising can be by { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body (sample C5) of the non-orientation ceramic of expression.

Equally, in the present embodiment,, except roasting condition changes the preparation that is different from sample E7 into, prepare in the same way and comprise the polycrystalline ceramic body that the crystal oriented ceramic of same composition is arranged with E7 in order to compare with sample E7.This polycrystalline ceramic body is labeled as sample C6.More specifically, the same way as during with preparation sample E7 prepares shaping sample D5, roasting shaping sample D5 under the following conditions, thus prepare sample C6.

That is, with the same way as of preparation sample E7, shaping sample D5 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1115 ℃, sample kept 1 hour down for 1115 ℃ in temperature.After this, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.Like this, just obtain comprising principal phase and be { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.84Ta _0.1Sb _0.06) O ₃The polycrystalline ceramic body (sample C6) of crystal oriented ceramic.

Shown in the following table 2 for the sample E7 and the composition of sample C5 and C6 of preparation thus, whether be orientated, the amount and the roasting condition of NN powder template.

Table 2

Sample number	Form				Whether be orientated	NaNbO 3The amount of template (at%)	The intensification condition	The top temperature condition		The cooling condition
											x	y	z	W	Temperature (℃)	Time (h)
	Sample E5	0.04 ?	0.54 ?	0.46 ?				0.06 ?	Orientation								5 ?	200℃/h ?	1125 ?	1 ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
Sample E6					? 0.04 ? ?	? 0.54 ? ?	? 0.46 ? ?			? 0.06 ? ?	Orientation	? 5 ? ?	200 ℃/h (to 920 ℃) → 65 ℃/h (to 1040 ℃) → 12 ℃/h (to 1125 ℃)	? 1125 ? ?	? 1 ? ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
	Sample C3	0.04	0.54	0.46				0.06	Non-orientation								0	200℃/h	1125	1	200℃/h
Sample C4					0.04	0.54	0.46			0.06	Orientation	5	200℃/h	1125	1	200℃/h
	Sample E7	? 0.04 ? ?	? 0.50 ? ?	? 0.10 ? ?				? 0.04 ? ?	Orientation								? 5 ? ?	200 ℃/h (to 955 ℃) → 46 ℃/h (to 1069 ℃) → 9 ℃/h (to 1115 ℃)	? 1115 ? ?	? 1 ? ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
Sample C5					0.04	0.50	0.10			0.04	Non-orientation	0	200℃/h	1115	1	200℃/h
	Sample C6	0.04	0.50	0.10				0.04	Orientation								5	200℃/h	1115	1	200℃/h

Embodiment 3

Present embodiment is for producing the example have with the polycrystalline ceramic body of the different compositions of polycrystalline ceramic body of embodiment 1 and embodiment 2.In the present embodiment, prepared the polycrystalline ceramic body (sample E8) that comprises crystal oriented ceramic, the principal phase of this crystal oriented ceramic is for having the isotropy perovskite-type compounds that chemical formula (1) is formed, wherein: x=0.02, y=0.5, z=0 and w=0.06, that is, by { Li _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃Isotropic perovskite-type compounds of expression.

In the preparation of sample E8, at first prepare the ceramic coarse particle powder (powders A of anisotropy shape; The NN powder).For this ceramic coarse particle powder, the preparation with embodiment 1 in the identical powder of powdered sample A1.

Then, with powdered sample Al, NN powder, KN powder, LS (LiSbO ₃) powder and NS (NaSbO ₃) powder weighs by stoichiometric ratio, obtain target and form { Li _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃, and form slurries, these slurries are shaped also generate powder agglomates after the degreasing.The implementation process of the preparation of slurries, shaping and degreasing is identical with the mode of embodiment 1.The powder agglomates that obtains thus is labeled as shaping sample D7.The ten minutes coincidence, the NN powder of these uses, KN powder, LS (LiSbO ₃) powder and NS (NaSbO ₃) median size of powder all is about 0.5 μ m.

After shaping sample D7 put into process furnace, temperature rise rate with 200 ℃/h rises to 1125 ℃ (temperature-rise periods) with temperature, sample keeps 1 hour (the first maintenance process) down for 1125 ℃ in temperature, rate of temperature fall with 200 ℃/h is cooled to 1100 ℃ (process of cooling) then, keeps 5 hours (the second maintenance process) down at 1100 ℃.Further make sample be cooled to room temperature, take out polycrystalline ceramic body then with the rate of temperature fall of 200 ℃/h.

Like this, just obtained polycrystalline ceramic body (sample E8), this polycrystalline ceramic body comprises principal phase and is { Li _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃Crystal oriented ceramic.

In the present embodiment, in order to compare, only use median size to prepare the polycrystalline ceramic body that same composition is arranged with sample E8 for the interim powders calcined of about 0.5 μ m with sample E8.This polycrystalline ceramic body is labeled as sample C7.When sample C7 was produced in preparation, the ceramic coarse particle powder that uses as template when not using preparation sample E8 was so sample C7 is non-orientation body.

That is, in the preparation of sample C7, preparation purity respectively is 99.99% or above Na ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes these powder by stoichiometric ratio, obtain { the Li that consists of of target pottery _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃With the organic solvent is medium, by using ZrO ₂The ball wet mixing was implemented to mix in 20 hours.To the mixed powder that obtains according to the mode identical with embodiment 1 750 ℃ of interim roastings 5 hours down, be that medium uses ZrO in addition with the organic solvent ₂Ball wet-milling 20 hours, obtaining median size thus is the interim powders calcined (particulate powders) of about 0.5 μ m.This powder is labeled as powdered sample B8.

Further, with the same way as of preparation sample C1 among the embodiment 1, B8 prepares slurries with powdered sample, adds caking agent and softening agent and mixing in slurries, with squeegee devices slurries is shaped.The powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm, make this powder agglomates degreasing and the CIP that stands subsequently handles through excess pressure combination and roll-in.The powder agglomates that obtains thus is labeled as shaping sample D8.

Then, shaping sample D8 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1100 ℃, sample kept 1 hour down for 1100 ℃ in temperature, be cooled to room temperature with the rate of temperature fall of 200 ℃/h after, take out polycrystalline ceramic body.Like this, just having obtained comprising can be by { Li _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃The polycrystalline ceramic body (sample C7) of the non-orientation ceramic of expression.

Equally, in the present embodiment,, except roasting condition changes the preparation that is different from sample E8 into, prepare two kinds in the same way and comprise the crystal oriented ceramic polycrystalline ceramic body that same composition is arranged with E8 in order to compare with sample E8.These polycrystalline ceramic bodies are labeled as sample C8 and sample C9 respectively.More specifically, prepare shaping sample D7 with the same way as of preparation during E8, roasting shaping sample D7 under the following conditions, thus prepare sample C8 and sample C9.

That is, in the preparation of sample C8, preparation shaping sample D7, put it into then in the process furnace, with the temperature rise rate of 200 ℃/h temperature is risen to 1100 ℃, sample kept 1 hour down for 1100 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature, take out polycrystalline ceramic body.Like this, just obtained comprising with { Li _0.02(K _0.5Na _0.5) _0.98(Nb _0.94Sb _0.06) O ₃Polycrystalline ceramic body (sample C8) for the crystal oriented ceramic of principal phase.

Sample C9 with the same terms of preparation sample C8 under prepare, be to be to carry out under 1125 ℃ except roasting when the preparation sample C8 in the highest holding temperature.

Shown in the following table 3 for the sample E8 and the composition of sample C7 to C9 of preparation thus, whether be orientated, NN powder template content and roasting condition.

Equally, in the present embodiment, the polycrystalline ceramic body that the sample E7 among preparation and the embodiment 2 has same composition promptly, comprises the polycrystalline ceramic body of crystal oriented ceramic, and the principal phase of this crystal oriented ceramic is can be by { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃The isotropy perovskite-type compounds of expression, wherein this polycrystalline ceramic body is for being added with Ag ₂O is the polycrystalline ceramic body of additive.This polycrystalline ceramic body is labeled as sample E9.

In the preparation of sample E9, at first prepare the ceramic coarse particle powder (powders A of anisotropy shape; The NN powder).For this ceramic coarse particle powder, the preparation with embodiment 1 in the identical powder of powdered sample A1.

Simultaneously, preparation is used for the powdered sample B5 of sample E7 preparation, with as particulate powders.

Then, according to embodiment 1 in identical mode, powdered sample A1 and powdered sample B5 are mixed by stoichiometric ratio, obtain target and form { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃Further add additive A g ₂O also mixes, and the amount that makes the Ag of adding is that target is formed { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃1 mole of %.After this, according to embodiment 1 in same way as, make the mixed powder that obtains form slurries, slurries are shaped and degreasing after generate powder agglomates.The powder agglomates that obtains thus is labeled as shaping sample D9.

After shaping sample D9 put into process furnace, temperature rise rate with 200 ℃/h rises to 1125 ℃ (temperature-rise periods) with temperature, sample is kept 5 hours (the first maintenance process) down for 1125 ℃ in this temperature, rate of temperature fall with 200 ℃/h is cooled to 1100 ℃ (process of cooling) then, keeps 10 hours (the second maintenance process) down for 1100 ℃ in temperature.Further the rate of temperature fall with 200 ℃/h is cooled to room temperature with sample, takes out polycrystalline ceramic body then.

Like this, just obtained being added with additive A g ₂O, comprise principal phase for { Li _0.04( _K0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃The polycrystalline ceramic body (sample E9) of crystal oriented ceramic.

In the present embodiment, in order to compare, only use that median size has same composition for the interim powders calcined of about 0.5 μ m prepares with sample E9, wherein fusion has additive A g with sample E9 ₂The polycrystalline ceramic body of O.This polycrystalline ceramic body is labeled as sample C10.The ceramic coarse particle powder that uses as template when not using preparation sample E9 during preparation sample C10 is so sample C10 is non-orientation body.

That is, in the preparation of sample C10, according to embodiment 2 in the same way as of preparation sample C5, at first prepare powdered sample B6 as interim roasting powder.Then with Ag ₂O joins among the powdered sample B6 as additive and mixes, and making the amount that adds Ag is that target is formed { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃1 mole of %.

Further, according to embodiment 1 in the same way as of preparation sample C1, prepare slurries with the powdered sample B6 that is added with additive, in slurries, add caking agent and softening agent and mix, with squeegee devices slurries are shaped.The powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm, make this powder agglomates degreasing and the CIP that stands subsequently handles through excess pressure combination and roll-in.The powder agglomates mark that obtains is thus made shaping sample D10.

Then, D10 puts into process furnace with the shaping sample, with the temperature rise rate of 200 ℃/h temperature is risen to 1100 ℃, and sample kept 1 hour down for 1100 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature with sample, took out polycrystalline ceramic body.

Like this, just obtained adding additive A g has been arranged ₂O, comprising can be by { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃The polycrystalline ceramic body (sample C10) of the non-orientation ceramic of expression.

Equally, in the present embodiment, in order to compare with sample E9, except roasting condition changes the preparation that is different from sample E9 into, prepare in an identical manner two comprise with E9 same composition is arranged, wherein fusion has additive A g ₂The polycrystalline ceramic body of the crystal oriented ceramic of O.These polycrystalline ceramic bodies are labeled as sample C11 and sample C12 respectively.More specifically, the same way as when producing E9 prepares shaping sample D9, roasting shaping sample D9 under the following conditions, thus prepare sample C11 and sample C12.

That is, in the production of sample C11, preparation shaping sample D9, put it into then in the process furnace, temperature is risen to 1100 ℃, sample was kept 1 hour down for 1100 ℃ in temperature with the temperature rise rate of 200 ℃/h, after the rate of temperature fall with 200 ℃/h is cooled to room temperature with sample, take out polycrystalline ceramic body.Like this, just obtained adding additive A g has been arranged ₂O, comprise principal phase for { Li _0.04(K _0.5Na _0.5) _0.96(Nb _0.86Ta _0.1Sb _0.04) O ₃The polycrystalline ceramic body (sample C11) of crystal oriented ceramic.

Sample C12 prepares identical the accompanying under the burning condition of preparation sample C11, except preparation sample C8 (?) in, roasting is that hold-time under 1135 ℃, the highest holding temperature is to carry out under 5 hours in the highest holding temperature.

Shown in the following table 3 for the sample E9 and the composition of sample C10 to C12 of preparation thus, whether be orientated, NN powder template content and roasting condition.

Table 3

Sample number	Form				Additive	Whether be orientated	NaNbO 3The amount of template (at%)	The intensification condition	The top temperature condition		The cooling condition
												x	y	z	w	Temperature (℃)	Time (h)
	Sample E8	0.02 ?	0.50 ?	0.00 ?					0.06 ?	- ?								Orientation	5 ?	200℃/h ?	1125 ?	1 ?	5 ℃/h (to 1100 ℃) → at 1100 ℃ of following 5 hours 200 ℃/h (to room temperature)
Sample C7					0.02	0.50	0.00	0.06			-	Non-orientation	0	200℃/h	1100	1	200℃/h
	Sample C8	0.02	0.50	0.00					0.06	-								Orientation	5	200℃/h	1100	1	200℃/h
Sample C9					0.02	0.50	0.00	0.06			-	Orientation	5	200℃/h	1125	1	200℃/h
	Sample E9	0.04 ?	0.50 ?	0.10 ?					0.04 ?	Ag 2O ?								Orientation	5 ?	200℃/h ?	1125 ?	5 ?	200 ℃/h (to 1100 ℃) → at 1100 ℃ of following 10 hours → 200 ℃/h (to room temperature)
Sample C10					0.04	0.50	0.10	0.04			Ag 2O	Non-orientation	0	200℃/h	1100	1	200℃/h
	Sample C11	0.04	0.50	0.10					0.04	Ag 2O								Orientation	5	200℃/h	1100	1	200℃/h
Sample C12					0.04	0.50	0.10	0.04			Ag 2O	Orientation	5	200℃/h	1135	5	200℃/h

Embodiment 4

Present embodiment is the example that preparation and the polycrystalline ceramic body of embodiment 1 to embodiment 3 have the polycrystalline ceramic body of different compositions, and adding in this polycrystalline ceramic body has MnO ₂As additive.That is, in the present embodiment, prepared the polycrystalline ceramic body (sample E10) that comprises crystal oriented ceramic, the principal phase of this crystal oriented ceramic is for having the isotropy perovskite-type compounds that chemical formula (1) is formed, wherein: x=0.065, y=0.55, z=0.09 and w=0.08, that is, and by { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃Isotropic perovskite-type compounds of expression.

In the preparation of sample E10, at first prepare the ceramic coarse particle powder (powders A of anisotropy shape; The NN powder).For this ceramic coarse particle powder, the preparation with embodiment 1 in the identical powder of powdered sample A1.

Then, according to embodiment 1 in identical mode prepare particulate powders.This particulate powders is labeled as powdered sample B7.

According to embodiment 1 in the same way as of preparation powdered sample B1 prepare sample B7, except with Na ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes obtains { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃Target pottery form, add additive MnO ₂And mix, making the amount that adds Mn is that target is formed { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃0.05 mole of %.Powdered sample B7 is the interim powders calcined (particulate powders) of the about 0.5 μ m of median size.

Then, similar to Example 1, by stoichiometric ratio weigh powdered sample A1 and powdered sample B7, do not comprised MnO ₂{ the Li that adds part _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃Target form, and form slurries, slurries are shaped and degreasing after generate powder agglomates.The implementation process of the preparation of slurries, shaping and degreasing is identical with the mode of embodiment 1.The powder agglomates that obtains thus is labeled as type sample D11.

After shaping sample D9 put into process furnace, temperature rise rate with 200 ℃/h rises to 1105 ℃ (temperature-rise periods) with temperature, sample keeps 5 hours (the first maintenance process) down for 1105 ℃ in temperature, and the rate of temperature fall with 5 ℃/h makes it be cooled to 1000 ℃ (process of cooling) then.Further, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.

Like this, just obtained adding additive (MnO has been arranged ₂), comprise principal phase for { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃The polycrystalline ceramic body (sample E10) of crystal oriented ceramic.

In the present embodiment, roasting condition is being changed into different with the preparation of sample E10, and other preparation method and sample E10 keep preparing the polycrystalline ceramic body that has with the E10 same composition under the same condition.This identified as samples is designated as sample E11.

More specifically, prepare shaping sample D11 according to the mode identical with preparation sample E10, roasting shaping sample D11 under the following conditions, thus prepare sample E11.

That is, D11 puts into process furnace with the shaping sample, and temperature is risen to 1105 ℃.In this section the period, temperature rise rate with 200 ℃/h rises to 900 ℃ with temperature, temperature rise rate with 45 ℃/h rises to 1020 ℃ with temperature, continuation rises to 1105 ℃ with the temperature rise rate of 9 ℃/h with temperature, simultaneously, in temperature-rise period, control temperature rise rate, so that the contraction of shaping sample D11 to be about 0.0005%/second or lower linear shrinkage (obtaining the contraction factor of constant rate of speed like this in the temperature range that sintering is taken place) takes place.

After this, the same way as according to production sample E10 the time is implemented first maintenance process and the process of cooling, prepares thus to comprise the polycrystalline ceramic body (sample E11) of crystal oriented ceramic that the principal phase of same composition is arranged with E10.

Equally, in the present embodiment,, only use median size to prepare the polycrystalline ceramic body that same composition is arranged with sample E10 and E11 for the interim powders calcined of about 0.5 μ m in order to compare with sample E10 and E11.This polycrystalline ceramic body is labeled as sample C13.When preparation sample C13, the ceramic coarse particle powder that uses as template when not using preparation sample E10 and E11 is so sample C13 is non-orientation body.

That is, in the preparation of sample C13, according to embodiment 1 in the same way as of preparation sample C1 at first prepare interim powders calcined.This identified as samples is designated as powdered sample B9.

Prepare the same of powdered sample B2 among the mode of preparation powdered sample B9 and the embodiment 1, except respectively being 99.99% or above Na with purity ₂CO ₃Powder, K ₂CO ₃Powder, Li ₂CO ₃Powder, Nb ₂O ₅Powder, Ta ₂O ₅Powder and Sb ₂O ₅Powder mixes by stoichiometric ratio, obtains { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃Target pottery form and add additive MnO ₂And mix, make that the amount that adds Mn is that target is formed { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃0.05 mole of %.Powdered sample B9 is that median size is the interim powders calcined of about 0.5 μ m.

Further, according to embodiment 1 in preparation sample C1 identical mode, B9 prepares slurries with powdered sample, adds caking agent and softening agent and mix in slurries, makes the slurries shaping with squeegee devices.The powder agglomates that obtains is stacked, obtain the thick tabular powder agglomates of 1.5mm, make this powder agglomates degreasing and the CIP that stands subsequently handles through excess pressure combination and roll-in.The powder agglomates that obtains thus is labeled as shaping sample D12.

Then, shaping sample D12 put into process furnace after, with the temperature rise rate of 200 ℃/h temperature is risen to 1105 ℃, sample kept 5 hours down for 1105 ℃ in temperature, after the rate of temperature fall with 200 ℃/h is cooled to room temperature with it, took out polycrystalline ceramic body.Like this, just obtained comprising the polycrystalline ceramic body (sample C13) of non-orientation ceramic, this non-orientation ceramic has additive (MnO for adding ₂), its principal phase is can be by { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃The pottery of expression.

Equally, in the present embodiment, in order to compare, change the preparation that is different from these samples into except roasting condition with sample E10 and E11, prepare polycrystalline ceramic body in the same way, this polycrystalline ceramic body comprises the crystal oriented ceramic that same composition is arranged with E10 and E11.This polycrystalline ceramic body is labeled as sample C14.

More specifically, the same way as during with preparation E10 and E11 prepares shaping sample D11, roasting shaping sample D11 under the following conditions, thus prepare sample C14.

That is, according to the same way as of preparation sample E10, D11 puts into process furnace with the shaping sample, with the temperature rise rate of 200 ℃/h temperature is risen to 1105 ℃, sample kept 5 hours down at 1105 ℃.After this, sample is cooled to room temperature with the rate of temperature fall of 200 ℃/h, takes out polycrystalline ceramic body then.Like this, just obtain adding additive (MnO2) being arranged, comprise principal phase is { Li _0.065(K _0.45Na _0.55) _0.935(Nb _0.83Ta _0.09Sb _0.08) O ₃The polycrystalline ceramic body (sample C14) of crystal oriented ceramic.

Shown in the following table 4 for the sample E10 and the composition of E11 and sample C13 and C14 of preparation thus, whether be orientated, the amount and the roasting condition of NN powder template.

Table 4

Sample number	Form				Additive	Whether be orientated	NaNbO 3The amount of template (at%)	The intensification condition	The top temperature condition		The cooling condition
												x ?	y ?	z ?	w ?	Temperature (℃)	Time (h)
	Sample E10	0.065 ?	0.55 ?	0.09 ?					0.08 ?	MnO 2?								Orientation	5 ?	200℃/h ?	1105 ?	5 ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
Sample E11					? 0.065 ? ?	? 0.55 ? ?	? 0.09 ? ?	? 0.08 ? ?			? MnO 2? ?	Orientation	? 5 ? ?	200 ℃/h (to 900 ℃) → 65 ℃/h (to 1020 ℃) → 12 ℃/h (to 1105 ℃)	? 1105 ? ?	? 5 ? ?	5 ℃/h (to 1000 ℃) → 200 ℃/h (to room temperature)
	Sample C13	0.065	0.55	0.09					0.08	MnO 2								Non-orientation	0	200℃/h	1105	5	200℃/h
Sample C14					0.065	0.55	0.09	0.08			MnO 2	Orientation	5	200℃/h	1105	5	200℃/h

Test case

In this test case, the performance of the polycrystalline ceramic body (sample E1-E11 and sample C1-C14) for preparing among the embodiment 1-4 is tested.

[bulk density]

The bulk density of each sample (sample E1-E11 and sample C1-C14) is measured by the following method.

Weight when measuring each sample drying (dry weight).Then, each sample is immersed in water, the clearance gap part for the treatment of each sample by water retting saturating after, measure the weight (weight in wet base) of each sample.Calculate the volume of the clearance gap that exists in each sample by the difference of weight in wet base and dry weight.Simultaneously, measure volume after each sample deducts clearance gap part with Archimedes's method.Like this, by calculate the bulk density of each sample divided by whole volumes (volume of clearance gap and the volume sum of removing the clearance gap rear section) with the dry weight of each sample.

The result who obtains is as shown in table 5.

[average orientation]

According to the Lotgering method, { 100} planar average orientation F (100) is parallel to herring bone (tape) planar plane surveying to each sample (sample E1 to sample E11, sample C1 to sample C3, sample C5 to sample C10 and sample C13) and obtains.Average orientation F calculates with mathematical formula 1.

The result who obtains is as shown in table 5.

[piezoelectric property d ₃₁]

Piezoelectricity distortion constant (d ₃₁) be a piezoelectric property that each sample is all tested (sample E1, E2, E5 to E9 and E11 and sample C1, C3, C5, C7, C10 and C13).

In piezoelectric property is measured, by each sample is cut, polishing and machining make disc shaped sample, this thickness of sample is 0.4-0.7mm, diameter is 8-11mm, upper and lower plane and herring bone plane parallel.Then, form the Au electrode, after vertical direction applies the polarization processing, at room temperature record piezoelectric constant d by resonance-antiresonance method on upper and lower plane ₃₁

The result who obtains is as shown in table 5.

Table 5

Sample number	Bulk density (g/cm 3)	(100) planar orientation degree (%)	Piezoelectric property d31 (pm/V)
				Sample E1	4.70	89	75
Sample E2	4.76	86	81
				Sample E3	4.73	84
Sample E4	4.68	84
				Sample C1	4.72	0	66
Sample C2	4.55	87
				Sample E5	4.70	73	135
Sample E6	4.76	71	138
				Sample C3	4.73	0	114
Sample C4	4.59
				Sample E7	4.71	84	121
Sample C5	4.70	0	96
				Sample C6	4.48	85
Sample E8	4.51	82	99
				Sample C7	4.47	0	67
Sample C8	4.37	82
				Sample C9	4.41	82
Sample E9	4.76	93	132
				Sample C10	4.74	0	113
Sample C11	4.14
				Sample C12	4.6
Sample E10	4.69	91
				Sample E11	4.72	90	99
Sample C13	4.72	0	84
				Sample C14	4.49

Contrast from table 5 between sample C1 and sample C2, sample C3 and sample C4, sample C5 and sample C6, sample 7 and sample C8, sample C10 and sample C11 and sample C13 and the sample 14 as can be seen, the non-orientation body that obtains under identical roasting condition is very big with the density variation of orientation body, compare with the non-orientation body that obtains under the identical roasting condition, the density of orientation body is smaller.This is considered to owing to adopted ceramic coarse particle powder that median size is different each other and particulate powders as raw material when preparation orientation body.

On the other hand, for instance, between sample E1 and sample C2, sample E5 and sample C4 and sample E10 and the sample C14 more as can be seen, with at a slow speed as when 40 ℃/h or the cooling of lower rate of temperature fall, density can greatly increase in process of cooling.

Equally, the result from sample E2 to sample E4 as can be seen, when rate of temperature fall was slack-off, density can significantly increase.

Further, from between sample E1 and sample E2, sample E5 and sample E6 and sample E10 and the sample E11 more as can be seen, by the heat-up rate in the control temperature-rise period, for example, when making being contracted in linear shrinkage and being 25%/h or lower generation of powder agglomates, the density of polycrystalline ceramic body can greatly strengthen.

In addition, between sample E2 to E4 and sample C2, sample E6 and sample C4, sample E7 and sample C6 and sample E11 and the sample C14 more as can be seen, when controlling heat-up rate and cooling rate simultaneously, the density of polycrystalline ceramic body can obtain bigger lifting.

For the sample of estimating piezoelectric property, as can be seen from Table 5,, can further improve piezoelectric property by arranging crystal face.

Simultaneously, in this test case, sample E7, sample C5 and three kinds of multicrystal polycrystalline ceramic body internal voids states of sample C6 are checked by using ultrasonoscopy instrument (SAT).The result who obtains is as shown in Fig. 1 to 3.The ten minutes coincidence, the external diameter that is used for each sample of SAT observation all is 8.5mm.

As can be seen from Figures 2 and 3, (Fig. 3) compares with comprising the non-orientation body sample C5 (Fig. 2) that uses the almost consistent raw material powder of particle diameter to prepare among the different ceramic coarse particle powder of particle diameter each other and the sample C6 that comprises crystal oriented ceramic that particulate powders prepares by using, and can be observed many spaces.On the other hand, by controlling as mentioned above among the sample E7 that heat-up rate and cooling rate prepare, though having used each other as the situation among the sample C3, different ceramic coarse particle powder and the particulate powders of particle diameter prepares the crystalline ceramic body, but C2 is similar with sample, is difficult to observe the space.

Verified for several pages as described above, according to this test case, by in heat treatment step, implementing temperature control as mentioned above, the generation in space in the polycrystalline ceramic body that can suppress to obtain, and can obtain highdensity polycrystalline ceramic body.

Claims (16)

1. method for preparing polycrystalline ceramic body, it comprises:

The preparation median size is that the ceramic coarse particle powder of 1-20 μ m and median size are the preparation process of 1/3 or littler particulate powders of described ceramic coarse particle powder median size, when described particulate powders and ceramic coarse particle powder sintering together, can produce polycrystalline ceramic body

Described ceramic coarse particle powder is mixed with particulate powders producing the mixing step of raw mix,

Make described raw mix be shaped with the forming step that produces molding and

Heat described molding, described molding is shunk, the described ceramic coarse particle powder of sintering and particulate powders to be preparing the heat treatment step of polycrystalline ceramic body simultaneously,

Wherein, in described heat treatment step, implement the temperature-rise period and the first maintenance process, temperature-rise period begins to heat with elevated temperature to molding, the first maintenance process remained on 1 ℃ of temperature T following 0.1 minute or longer with molding, 600≤T1≤1 wherein, 500, implement second maintenance process and/or the process of cooling simultaneously, the second maintenance process remains below molding 2 ℃ of the temperature T following 10 minutes or longer of 1 ℃ of temperature T, T2 〉=300 wherein, and the described second maintenance process is after the first maintenance process, process of cooling begins molding is cooled off for 1 ℃ from temperature T with 60 ℃/h or lower rate of temperature fall, and described process of cooling is after the first maintenance process.

2. the method for preparing polycrystalline ceramic body of claim 1, when wherein the ceramic coarse particle powder mixed with particulate powders in described mixing step, the blended ratio of ceramic coarse particle powder was per 100 weight part ceramic coarse particle powder and particulate powders total amount 0.01-70 weight part.

3. claim 1 or 2 the method for preparing polycrystalline ceramic body, wherein in the described first maintenance process, keep temperature T 1 (℃) be 1000≤T1≤1300.

4. the method for preparing polycrystalline ceramic body of one of claim 1 to 3, wherein the maintenance temperature T 1 in the described first maintenance process (℃) and the described second maintenance process in maintenance temperature T 2 (℃) between satisfy and concern 5≤(T1-T2)≤300.

5. the method for preparing polycrystalline ceramic body of one of claim 1 to 4, wherein the rate of temperature fall in described process of cooling is 40 ℃/h or lower.

6. the method for preparing polycrystalline ceramic body of one of claim 1 to 5 wherein in described temperature-rise period, is controlled temperature rise rate so that the contraction that molding causes because of being heated takes place with 25%/h or littler linear shrinkage speed.

7. the method for preparing polycrystalline ceramic body of claim 6, wherein in described temperature-rise period, the control temperature rise rate so that the contraction that molding causes because of being heated almost with constant linear shrinkage speed, ℃ to T1 ℃ temperature range, take place at (T1-50).

8. it is 3 to 100 anisotropic shape that the method for preparing polycrystalline ceramic body of one of claim 1 to 7, wherein said ceramic coarse particle powder have average aspect ratio.

9. the method for preparing polycrystalline ceramic body of one of claim 1 to 8, wherein said polycrystalline ceramic body comprise the crystal oriented ceramic that the particular crystal plane A of each crystal grain wherein is orientated.

10. the method for preparing polycrystalline ceramic body of claim 9, wherein in described polycrystalline ceramic body, cube { the 100} planar orientation is described crystal face A, and its orientation degree is 30% or bigger according to the puppet of Lotgering method.

11. the method for preparing polycrystalline ceramic body of claim 9 or 10, wherein said ceramic coarse particle powder comprises and has the orientation planar coarse particles that forms by particular crystal plane orientation, orientation plane in described coarse particles has the lattice that is complementary with the particular crystal plane A that constitutes polycrystalline ceramic body, and in forming step, implement to be shaped so that almost arrange by same direction on coarse grained orientation plane.

12. the method for preparing polycrystalline ceramic body of claim 11, wherein said orientation plane are pseudo-cube { 100} plane.

13. the method for preparing polycrystalline ceramic body of one of claim 1 to 12, wherein said polycrystalline ceramic body comprise isotropic perovskite-type compounds as principal phase.

14. the method for preparing polycrystalline ceramic body of one of claim 1 to 13, wherein said polycrystalline ceramic body comprise following by the represented isotropic perovskite-type compounds of chemical formula (1) as principal phase: { Li _x(K _1-yNa _y) _1-x(Nb _1-z-wTa _zSb _w) O ₃, wherein 0≤x≤0.2,0≤y≤1,0≤z≤0.4,0≤w≤0.2 and x+z+w＞0.

15. the method for preparing polycrystalline ceramic body of claim 14, wherein in every mole by the represented isotropic perovskite-type compounds of chemical formula (1), described polycrystalline ceramic body contains one or more of 0.0001 to 0.15 mole and is selected from other following element: the metallic element, semimetallic elements, transition metal, precious metal element and the alkali earth metal that belong to the periodic table of elements the 2nd to 15 family.

16. the method for preparing polycrystalline ceramic body of claim 15, wherein add described other element by one or more elements that are selected from Li, K, Na, Nb, Ta and Sb in the represented isotropy perovskite-type compounds of chemical formula (1) are replaced, its additional proportion is 0.01 to 15at%.

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