CN1856885A

CN1856885A - Multilayer piezoelectric device

Info

Publication number: CN1856885A
Application number: CNA2004800276514A
Authority: CN
Inventors: 冈村健; 坂上胜伺; 近藤光央
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2003-09-25
Filing date: 2004-09-22
Publication date: 2006-11-01
Also published as: JP2005101274A; CN101540367A; JP4803956B2

Abstract

A multilayer piezoelectric device with excellent durability is disclosed wherein the amount of displacement does not vary even when the multilayer piezoelectric device is continuously driven under high-voltage, high-pressure conditions for a long time. The multilayer piezoelectric device comprises a multilayer body composed of piezoelectric layers and internal electrodes alternately stacked upon one another and external electrodes respectively formed on a first lateral surface and a second lateral surface. One of every two adjoining internal electrodes is connected to the external electrode on the first lateral surface, while the other internal electrode is connected to the external electrode on the second lateral surface. The multilayer piezoelectric device contains an alkali metal in an amount of not less than 5 ppm and not more than 300 ppm.

Description

Multi-layer piezoelectric element

Technical field

The present invention relates to multi-layer piezoelectric element and injection apparatus, for example relate to and be used in the fuel injection device of lift-launch at motor car engine, the liquid injection apparatus of ink-jet etc., driving element in the precision positioning device of Optical devices etc. or the anti-locking apparatus of vibration etc., and carry at combustion pressure sensor, knock transducer, acceleration transducer, load transducer, ultrasonic sensor, voltage sensitive sensor, sensor element in the yaw rate sensor etc., and carry at piezoelectric gyroscope, Piezoelectric switches, piezoelectric transformer, multi-layer piezoelectric element and injection apparatus in the circuit element in the piezoelectricity breaker etc.

Background technology

All the time, as multi-layer piezoelectric element, the known stack-up type piezo-activator that has alternately lamination piezoelectrics and internal electrode to form.In the stack-up type piezo-activator, be categorized as slug type simultaneously, with these 2 types on the accumulation type of alternately lamination piezoelectric ceramic and internal electrical pole plate, if consider from the aspect that lower voltage, manufacturing cost reduce, then the stack-up type piezo-activator of slug type is favourable to thin layerization simultaneously, and with respect to durability also is favourable, so shown its superiority.

Fig. 2 is the figure of the existing multi-layer piezoelectric element of expression shown in the patent documentation 1, and the laminate 200 that is formed by lamination piezoelectrics 21 alternately and internal electrode 22 constitutes with the outer electrode 23 that is formed on the opposed a pair of side mutually.Laminate 200 is by the piezoelectrics 21 that constitute it and internal electrode 22 lamination and constituting alternately, and internal electrode 22 is not to be formed on piezoelectrics 21 interareas on the whole, but becomes so-called partial electrode structure.The mode of exposing in the side of different laminate 200 every one deck ground with the internal electrode 22 of this partial electrode structure and about this partial electrode of lamination internal electrode 22 of constructing differently mutually.In addition, two interarea side laminations on the lamination direction of laminate 200 have inert layer 24,24.And, on the mutual opposed a pair of side of laminate 200, be formed with outer electrode 23, thereby can connect internal electrode 22 every one deck ground in the mode that connects above-mentioned each internal electrode 22 that exposes.

Under the situation that existing multi-layer piezoelectric element is used as piezo-activator, and then lead utilized scolding tin and be fixed on the outer electrode 23, thereby externally 23 at the electrode current potential that applies regulation drives.Particularly, in recent years, because require small-sized multi-layer piezoelectric element under bigger pressure, to guarantee bigger addendum modification, so apply higher electric field, long-time continuous drives this operation.

Multi-layer piezoelectric element is made as follows.At first, the internal electrode paste is printed onto on the ceramic green sheet of the raw material that includes piezoelectrics 21 with the pattern that becomes regulation electrode structure shown in Figure 2, the lamination formed body of making the lamination multi-disc be coated with the raw cook of this internal electrode paste and obtaining, again the lamination formed body is carried out sintering, just produce laminate 200 with this.Utilize sintering outer electrode 23 be formed at a pair of side of laminate 200 on, thereby just obtain multi-layer piezoelectric element thereafter.

When making existing laminate 200, the situation that has alkali metal to sneak into.That is, alkali metal is as the constituent of oxide, carbonate or nitrate etc. and be contained in or be blended into binder materials as unavoidable impurities and sneak in the raw material of the piezoelectrics 21 in raw cook.In order to improve agglutinating property, have and add glass powder in the raw material of piezoelectrics 21 situation, but in the glass powder of majority, all include alkali-metal oxide again.And then in manufacturing process, alkali metal is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 21, perhaps spreads from sintering atmosphere gas.

On the other hand, the situation that also has halogens to sneak into.That is, halogens is contained in or is blended in the raw material and binder materials of piezoelectrics 21 as unavoidable impurities as fluoride, chloride, bromide, iodide or astatine compound.Again, in manufacturing process, in mixing pulverizing, make water, perhaps if the raw material of long-term keeping piezoelectrics 21 then produces sneaking into of halogen etc.And halogen is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 21, perhaps spreads from sintering atmosphere gas.

And then, the situation that also has these both sides of above-mentioned alkali metal and halogens to sneak into by the compound of NaCl etc. from human body.

Again, all the time, use the alloy of silver and palladium, and then for while sintering piezoelectrics 21 and internal electrode 22, the metal of internal electrode 22 is formed to make to silver-colored 70%wt, palladium 30%wt and is used (for example, with reference to patent documentation 2) as internal electrode 22.

Like this, do not use by the metal of silver 100% and form the internal electrode that constitutes, and be to use by the metal that contains the silver palladium alloy that includes palladium form the internal electrode that constitutes be because: in the silver that does not include palladium 100% is formed, give under the situation of potential difference between to pair of opposed electrodes, the silver that can produce in the electrode moves to the so-called silver-colored transport phenomena of negative pole with the positive pole of mode from this pair of electrodes via element surface.This phenomenon produces in the atmosphere of high temperature, high humidity all the more significantly.

When making internal electrode 22, there is alkali metal to be blended into situation in the internal electrode 22.That is, alkali metal is as the constituent of oxide, carbonate or nitrate etc. and be contained in or be blended in the raw material and binder materials of internal electrode 22 as unavoidable impurities.In order to improve agglutinating property, have and add glass powder in the raw material of internal electrode 22 situation, but in the glass powder of majority, all include alkali-metal oxide again.And in manufacturing process, alkali metal is sneaked into from the crushing ball that mixes the raw material of pulverizing internal electrode 22, perhaps spreads from sintering atmosphere gas.

On the other hand, also there is halogens to be blended into situation in the internal electrode 22.That is, halogens is contained in or is blended in the raw material and binder materials of internal electrode 22 as unavoidable impurities as fluoride, chloride, bromide, iodide or astatine compound.Again, in manufacturing process, if the raw material of long-term keeping internal electrode 22 then produces sneaking into of halogens.And halogens spreads from sintering atmosphere gas.

And then, the situation that also has above-mentioned alkali metal and halogen both sides to sneak into by the compound of NaCl etc. from human body.

When making existing outer electrode 23, there is alkali metal to be blended into situation in the outer electrode 23.That is, alkali metal is as the constituent of oxide, carbonate or nitrate etc. and be contained in or be blended in the raw material and binder materials of outer electrode 23 as unavoidable impurities.In order to improve agglutinating property, have and add glass powder in the raw material of outer electrode 23 situation, but in the glass powder of majority, all include alkali-metal oxide again.And in manufacturing process, alkali metal is sneaked into from the crushing ball that mixes the raw material of pulverizing outer electrode 23, perhaps spreads from sintering atmosphere gas.

On the other hand, also there is halogens to be blended into situation in the outer electrode 23.That is, halogens is contained in or is blended in the raw material and binder materials of outer electrode 23 as unavoidable impurities as fluoride, chloride, bromide, iodide or astatine compound.Again, in manufacturing process, in mixing pulverizing, make water, perhaps if the raw material of long-term keeping outer electrode 23 then produces sneaking into of halogen etc.Again, halogens is sneaked into from the crushing ball that mixes the raw material of pulverizing outer electrode 23, perhaps spreads from sintering atmosphere gas.

Again, when making multi-layer piezoelectric element, be printed onto on the raw cook that raw material and adhesive by piezoelectrics 21 constitute and when the sheet and sintering that obtain, following situation arranged at the raw material paste that the lamination multi-disc will be made of the raw material and the adhesive of internal electrode 22: be contained in above-mentioned alkali-metal concentration in piezoelectrics 21 and the internal electrode 22 from the less side's diffusion of a bigger direction.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.Again, similarly, following situation is arranged also: the concentration that is contained in the halogen in piezoelectrics 21 and the internal electrode 22 is from the less side's diffusion of a bigger direction.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.

And then, be printed onto on a pair of side of laminate 200 at the raw material paste that will constitute and when the sintering, following situation arranged also: be contained in outer electrode 23 and spread from the less side of a bigger direction with alkali-metal concentration in the piezoelectrics 21 that outer electrode 23 contact by the raw material and the adhesive of outer electrode 23.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.Simultaneously, following situation is also arranged: be contained in outer electrode 23 and with internal electrode 22 that outer electrode 23 contacts in alkali-metal concentration from the less side's diffusion of a bigger direction.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.

Similarly, following situation is also arranged: be contained in outer electrode 23 and with piezoelectrics 21 that outer electrode 23 contacts in the concentration of halogen from the less side's diffusion of a bigger direction.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.Simultaneously, following situation is also arranged: halogen from be contained in outer electrode 23 and with internal electrode 22 that outer electrode 23 contacts the bigger less side's diffusion of a direction of concentration of halogen.At this moment, the distance of diffusion is different because of sintering temperature, sintering time and concentration ratio.

In addition, alkali metal has extraordinary effect to the sintering of pottery, thereby use as sintering adjuvant all the time, but if alkali-metal interpolation is too much, then the high-frequency dielectric loss becomes big, so be used in generation if the high-frequency dielectric loss becomes the transmission loss change IC encapsulation of this problem greatly of big then signal, perhaps produce if the high-frequency dielectric loss becomes big then quality coefficient Q value and diminish in the pottery in the capacitor etc. of problems such as this problem or self-heating, from preferential this point of high-frequency dielectric characteristic is considered, make alkali metal reduce this operation in order to reduce dielectric loss.With respect to this, in multi-layer piezoelectric element, different with these purposes, be used for considering from making with the dc high voltage driving element and with the low frequency below the 1kHz, the high-frequency dielectric loss is not preferential, in order to obtain the insulation characterisitic under high voltage in piezoelectrics 21, what pursued is to form fine and close sintered body, so use alkali metal as various sintering adjuvants.

All the time, as strong medium pottery or piezoelectric ceramic, have with PbTiO ₃-PbZrO ₃(the following PTZ that slightly is called) is the composite perofskite type compound of principal component.Its constituent of these materials almost all is a pottery, and after raw material or powders calcined were configured as the shape of regulation, at high temperature sintering was made.In these existing piezoelectric ceramic, recently make the piezoelectric ceramic of kind of specific character by the composition of selection component, thereby be used in the purposes of actuator, ceramic filter, piezoelectric buzzer etc. according to purposes.For example, piezo-activator, the existing electromagnetic actuator that forms with coiling coil on magnetic relatively has following feature: it is less to consume electric power or caloric value, and answer speed is fast, and addendum modification is big, and size, weight are little etc.But PZT is that pottery has following shortcoming: 4 bending strengths are about 100Mpa or add and be easy to generate crackle man-hour or collapse broken.

Therefore, in patent documentation 3, when suppressing grinding collapse broken or crackle is a purpose, the PZT series piezoelectric ceramic of Si that contains Al, 0.01～0.04% weight of Fe, 0.01～0.04% weight of 0.01～0.3% weight as accessory ingredient is disclosed.

In the PZT series piezoelectric ceramic shown in the patent documentation 1, Al, the Si that contains as accessory ingredient forms liquid phase easily in the sintering stage, and the grain boundary at sintered body after sintering is finished forms with PbO-Al ₂O ₃-SiO ₂Glassy phase for main body.With this, just can under than the low temperature of the piezoelectric ceramic that does not contain these accessory ingredients, make the sintered body densification, can make crystal grain-growth again.Therefore the crackle in the time of can suppressing grinding or collapse brokenly, and on this side of glassy phase, the destruction toughness value is than above-mentioned perovskite-type compounds height, so can improve the destruction toughness value of sintered body.

Again, as multi-layer piezoelectric element, the known stack-up type piezo-activator that has alternately lamination piezoelectrics and internal electrode to form.In the stack-up type piezo-activator, be categorized as slug type simultaneously, with these 2 types on the accumulation type of alternately lamination piezoelectric ceramic and internal electrical pole plate, if consider from the aspect that lower voltage, manufacturing cost reduce, then the stack-up type piezo-activator of slug type is favourable for thin layerization simultaneously, so shown its superiority.

Patent documentation 1: the spy opens clear 61-133715 communique

Patent documentation 2: open flat 1-130568 communique in fact

Patent documentation 3: the spy opens flat 14-220281 communique

Summary of the invention

But, using under the situation of multi-layer piezoelectric element under the environment of high temperature, high pressure, following problem is being arranged:, then be contained in following 2 kinds of foreign ionizations wherein if the temperature of multi-layer piezoelectric element rises, intrinsic resistance with this multi-layer piezoelectric element changes, thereby addendum modification changes.

Thereby, under the existing multi-layer piezoelectric element with above explanation is used in situation in the fuel injection device etc. of motor car engine chronically, because the addendum modification of wishing gradually changes, the problem of generation device misoperation is so pursuing the inhibition of variation of the addendum modification in the long-time continuous running and the raising of durability.

Again, the ambient temperature difference addendum modification that has because of using from piezoelectrics also changes this characteristic, and following problem is arranged: because of component temperature rises, produce the volumetric expansion of internal electrode, thereby the piezo-activator addendum modification changes.Again,, produce load fluctuation in driving, thereby produce the problem that power supply is applied burden with respect to voltage-controlled power supply because of addendum modification changes.And then, if the rate of change of addendum modification is big, following problem is arranged then: addendum modification self deterioration sharp not only, also the producing component temperature rises and causes heat dissipation capacity to strengthen this thermal runaway phenomenon, thus element destroys.

And then, in recent years,, under bigger pressure, guarantee bigger addendum modification for piezo-activator is arranged in the injection apparatus, carried out applying the operation of higher electric field, long-time continuous driving.But, if piezo-activator is applied high electric field, then the junction surface of internal electrode and outer electrode produces the significant amount of localized heat that the path because of conductivity narrows down and causes, flexible ability with this piezo-activator reduces, thereby has utilized the long-term Continuous Drive of the injection apparatus of piezo-activator to become difficult.

For the temperature that suppresses said elements rises, pursue the internal electrode littler than resistance again.But, following problem is arranged: the ratio resistance value of silver-palladium alloy because of the reason of its ratio of components, becomes the remarkable high resistance of ratio resistance value than silver or palladium monomer, in the composition of the silver-palladium alloy of silver-colored 70% weight, palladium 30% weight, become 1.5 times resistance of palladium monomer.And if the sintered density of internal electrode is low, then resistance becomes higher.

But, in patent documentation 3 described piezoelectric ceramic, have the volume intrinsic resistance through the time change to wait problem in reliability, these upper variations of durability.For example, using under the situation of piezoelectric ceramic as vehicle mounted piezo-activator etc., reliability, durability are very important key elements.

Again, following problem is arranged when the processing piezoelectric ceramic: if carry out ultrasonic washing, then causing threshing, so surface roughness descends, perhaps is not only the porcelain surface, and inner crystal grain has also produced damage, thereby durability reduces.

Therefore, the present invention has considered that just the problems referred to above make, and a kind of under the situation that long-time continuous under the environment of high voltage, high pressure drives even its purpose is to provide, addendum modification does not change yet, the multi-layer piezoelectric element of good endurance.

Again, though the object of the present invention is to provide a kind of under the situation that long-time continuous under high electric field, the high pressure drives, the also multi-layer piezoelectric element that does not produce the piezoelectric ceramic of insulation breakdown, good endurance and use this piezoelectric ceramic.

Addendum modification does not change present inventors, the multi-layer piezoelectric element of good endurance in order to provide, and discusses, and its result is as follows.

At first the first, be not in the piezoelectrics of principal component with alkali metal, ground includes under the alkali-metal situation as impurity and more than a certain amount of in piezoelectrics 21, produces the variation of above-mentioned addendum modification.Promptly, be not under the situation of principal component with alkali metal, mainly the situation that alkali metal exists as ion in piezoelectrics is more, if the outer electrode to multi-layer piezoelectric element applies voltage under such state, particularly, in high-tension DC electric field, drive multi-layer piezoelectric element, then alkali metal ion moves between internal electrode, if long-time continuous drives multi-layer piezoelectric element, then the intrinsic resistance of multi-layer piezoelectric element changes, thereby addendum modification originally reduces.

And then, under the situation that alkali metal ion is concentrated partly, following problem is arranged: produce local short circuit between internal electrode, stop thereby driving.This short circuit is easy to generate under situation about driving under the high environment of high temperature, humidity.

Containing this alkali-metal problem not only produces under the situation in being contained in piezoelectrics, under the situation in being contained in internal electrode, for example, if apply under the voltage condition at outer electrode to multi-layer piezoelectric element, particularly, drive under high-tension DC electric field, then alkali metal ion is from becoming anodal internal electrode to moving between the internal electrode that becomes negative pole by piezoelectrics, intrinsic resistance with this multi-layer piezoelectric element changes, thereby addendum modification originally reduces.And then, under situation about containing in outer electrode, if apply under the voltage condition at outer electrode to multi-layer piezoelectric element, particularly, under high-tension DC electric field, drive, then alkali metal ion moves to similarly becoming anodal internal electrode or becoming by piezoelectrics between the internal electrode of negative pole from becoming anodal outer electrode, change with the intrinsic resistance of this multi-layer piezoelectric element, thereby addendum modification originally reduces.

By these moving of alkali metal ion of producing of position arbitrarily, just have the intrinsic resistance of multi-layer piezoelectric element to change, thereby addendum modification change this problem.And, the alkali metal ion that moves through of alkali metal ion produces from the little side diffusion of the big direction concentration of alkali metal ion concentration, side by side, optionally move with respect to the voltage that applies from the outside to opposite polarity negative pole direction with alkali metal ion.

The second, in piezoelectrics, include under the situation of halogen as impurity, produce under the variation of the above-mentioned addendum modification situation that halogen exists as ion in piezoelectrics.That is, apply under the voltage condition, particularly as if outer electrode at multi-layer piezoelectric element, under high-tension DC electric field, drive, halide ionization then, metal ion moves as electrolyte ingredient, the intrinsic resistance of element originally changes, thereby addendum modification reduces.Thereby if so mobile change also has following problem at most: the migration that is contained in the metal in internal electrode or the outer electrode is quickened, and causes short circuit easily between internal electrode partly, stops thereby driving.This short circuit is easy to generate under situation about driving under the high environment of high temperature, humidity.

The problem that contains this halogen not only produces being contained under the situation of piezoelectrics, also produce under the situation in being contained in internal electrode or outer electrode, for example produce following problem: halogens such as Ionized chlorine combine with the moisture of outer gas and form electrolyte ingredient, with the equal effect ground corroding electrode of this and hydrochloric acid, perhaps in that being applied under the high-tension situation, element produces spark, the metal that perhaps constitutes electrode is dissolved in the electrolyte ingredient as ion, formation constitutes the precipitate that metal and halogen constitute by electrode, cause defective insulation, stop thereby driving.And then, containing under the situation of internal electrode, if apply under the voltage condition at outer electrode to multi-layer piezoelectric element, particularly, under high-tension DC electric field, drive, then halide ion moves to becoming between anodal internal electrode by piezoelectrics from the internal electrode that becomes negative pole, and with the intrinsic resistance variation of this multi-layer piezoelectric element, thereby addendum modification originally reduces.And then, be contained under the situation of outer electrode, if apply under the voltage condition at outer electrode to multi-layer piezoelectric element, particularly, under high-tension DC electric field, drive, then halide ion moves to becoming between anodal internal electrode to the internal electrode that similarly becomes negative pole or by piezoelectrics from the outer electrode that becomes negative pole, and with the intrinsic resistance variation of this multi-layer piezoelectric element, thereby addendum modification originally reduces.

By these moving of halide ion of producing of position arbitrarily, just produce following problem: the intrinsic resistance of multi-layer piezoelectric element changes, thereby addendum modification changes, perhaps halogen such as Ionized chlorine combines with the moisture of outer gas and forms electrolyte ingredient, in that being applied under the high-tension situation, element produces spark with this, the metal that perhaps constitutes electrode is dissolved in the electrolyte ingredient as ion, formation constitutes the precipitate that metal and halogen constitute by electrode, cause defective insulation, stop thereby driving.And the halide ion that moves through of halide ion produces from the little side diffusion of the big direction concentration of halogen ion concentration, side by side, optionally moves to the opposite polarity negative pole direction with halide ion with respect to the voltage that applies from the outside.

If containing alkali-metal problem produces simultaneously with the problem that contains halogen, then also produce following problem when separately problem side by side produces: attachment of moisture is when multi-layer piezoelectric element surperficial, form electrolyte ingredient by Ionized alkali metal, thereby in that being applied under the high-tension situation, element produces spark, perhaps if the electrolyte ingredient drying then forms salt, so corrosion internal electrode 22 and outer electrode 23 cause defective insulation, stop thereby driving.

First multi-layer piezoelectric element of the present invention comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, one side's of the internal electrode of adjacency internal electrode is connected in outer electrode in first side, and the opposing party's internal electrode is connected in outer electrode in second side; Include the following alkali metal of the above 300ppm of 5ppm.

Again, in first multi-layer piezoelectric element of the present invention, described piezoelectric body layer include below the above 500ppm of 5ppm alkali metal also can, also can at the alkali metal that described internal electrode includes below the above 500ppm of 5ppm.And then, in first multi-layer piezoelectric element of the present invention, also can at the alkali metal that described outer electrode includes below the above 500ppm of 5ppm.

In first multi-layer piezoelectric element of the present invention, described alkali metal is also can more than at least a among Na, the K.

Again, in first multi-layer piezoelectric element of the present invention, and then the above 1000ppm of 5ppm includes halogen followingly and also can.

In above first multi-layer piezoelectric element of the present invention,, then can suppress the existence of the alkali metal ion in piezoelectrics, internal electrode or the outer electrode as if being that alkali-metal amount is limited in the above-mentioned scope with the impurity in the multi-layer piezoelectric element.With this,, thereby can prevent the variation of the addendum modification of wishing even under the situation that long-time continuous under the environment of high voltage, high pressure drives, also the temperature of multi-layer piezoelectric element can be remained necessarily.Consequently, can provide high multi-layer piezoelectric element of the misoperation of restraining device and not short circuit, good endurance reliability and the injection apparatus that uses this multi-layer piezoelectric element.

Second multi-layer piezoelectric element of the present invention comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, one side's of the internal electrode of adjacency internal electrode is connected in outer electrode in first side, and the opposing party's internal electrode is connected in outer electrode in second side; Include the following halogens of the above 1000ppm of 5ppm.

In second multi-layer piezoelectric element of the present invention, described piezoelectrics include below the above 1500ppm of 5ppm halogen also can, also can at the halogens that described internal electrode includes below the above 1500ppm of 5ppm.

In second multi-layer piezoelectric element of the present invention, also can at the halogens that described outer electrode includes below the above 1500ppm of 5ppm again.

Again, in second multi-layer piezoelectric element of the present invention, described halogens is also can more than at least a among Cl, the Br.

In above second multi-layer piezoelectric element of the present invention, be restricted to the afore mentioned rules amount as if the amount that with the impurity in the multi-layer piezoelectric element is halogens, then just can suppress the halogens ionization in piezoelectrics, internal electrode or the outer electrode.With this, even under the situation that long-time continuous under the environment of high voltage, high pressure drives, the temperature of multi-layer piezoelectric element can be remained necessarily, thereby the addendum modification of wishing can not change substantially yet.Consequently, can provide high multi-layer piezoelectric element of the misoperation of restraining device and not short circuit good endurance reliability and the injection apparatus that uses this multi-layer piezoelectric element.

In addition, include at the same time under the situation of alkali metal and halogens, also can obtain effect same as described above.

The 3rd multi-layer piezoelectric element of the present invention comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, one side's of the internal electrode of adjacency internal electrode is connected in outer electrode in first side, and the opposing party's internal electrode is connected in outer electrode in second side; 1 * 10 ⁹The rate of change of the component size that the component size after the Continuous Drive more than inferior is preceding with respect to driving is in 1%.

Again, in the 3rd multi-layer piezoelectric element of the present invention, 1 * 10 ⁹The rate of change of the gauge of the described internal electrode that the gauge of the described internal electrode after the Continuous Drive more than inferior is preceding with respect to driving is in 5%.

In the 3rd multi-layer piezoelectric element of the present invention that constitutes like this, even Continuous Drive, in fact addendum modification does not change yet, thus the not misoperation of generation device, and then, have the good durability of no thermal runaway.

Again, in the 3rd multi-layer piezoelectric element of the present invention, if the rate of change of gauge of the described internal electrode before and after the Continuous Drive is in 5%, then the rate of change that can make component size in 1%, thereby can access same effect.

Again, in first to the 3rd multi-layer piezoelectric element of the present invention, be preferably and in described internal electrode, be added with metal constituent and inorganic composition, just can make the adhering to of interface of described internal electrode and described piezoelectrics connect airtight the intensity increase with this, thereby can prevent peeling off of described internal electrode and described piezoelectrics.Described inorganic composition is preferably with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component.

And then in first to the 3rd multi-layer piezoelectric element of the present invention, being preferably described piezoelectrics is principal component with the perofskite type oxide.

Again, if make described piezoelectrics with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component, then described piezoelectrics of sintering and described internal electrode simultaneously, thus can shorten sintering circuit, and can reduce the ratio resistance of described internal electrode.

And then the sintering temperature of described laminate is preferably more than 900 ℃ below 1000 ℃.

Again, and then the deviation by making the composition in the described internal electrode is below 5% before and after sintering, just can constitute to follow the flexible described internal electrode that the driving because of multi-layer piezoelectric element produces, so can suppress peeling off of described internal electrode.

Again, the 4th multi-layer piezoelectric element of the present invention is alternately lamination piezoelectric body layer and internal electrode and the multi-layer piezoelectric element that forms; Described piezoelectric body layer is with PbTiO ₃-PbZrO ₃Be principal component, the Si amount is the above and not enough 1000ppm of 5ppm.

With this PbTiO ₃-PbZrO ₃Be principal component, the piezoelectric body layer that 5ppm above and not enough 1000ppm ground contains Si does not form glassy phase in the grain boundary, thus can reduce the volume intrinsic resistance through the time variation.Therefore, even drive in long-time continuous under high electric field, the high pressure under the situation of the multi-layer piezoelectric element used described piezoelectric body layer, outer electrode and internal electrode are also and do not break.Thereby, the multi-layer piezoelectric element of good endurance can be provided.

In the 4th multi-layer piezoelectric element of the present invention, be preferably described Si in the grain boundary segregation, and the thickness of this grain boundary is below 1nm.

Again, in first to fourth multi-layer piezoelectric element of the present invention, is principal component by making the metal constituent in the described internal electrode with VIII family metal and/or Ib family metal, just can form and form described internal electrode, so be sintered into possibility with the high described piezoelectrics of sintering temperature the time with metal with high-fire resistance.

And then, in first to fourth multi-layer piezoelectric element of the present invention, the amount of the VIII family metal in making described internal electrode is that the amount of M1 (% weight), Ib family metal is when being M2 (% weight), satisfy 0＜M1≤15,85≤M2＜100, M1+M2=100 can make the ratio resistance of described internal electrode little with this, even, also can suppress the heating of described internal electrode so long-time continuous drives multi-layer piezoelectric element.And, rise because can suppress the temperature of multi-layer piezoelectric element, so can make element addendum modification stabilisation.

Again, in first to fourth multi-layer piezoelectric element of the present invention, described VIII family metal be among Ni, Pt, Pd, Rh, Ir, Ru, the Os at least a more than, Ib family metal be among Cu, Ag, the Au at least a more than, just can use the one of any of alloy raw material and mixed powder raw material with this raw material as described internal electrode.

And then, described VIII family metal be among Pt, the Pd at least a more than, Ib family metal be among Ag, the Au at least a more than, just can form the good internal electrode of thermal endurance and acid resistance with this.

Again, described Ib family metal be Cu also can, described VIII family metal is that Ni also can.

And then described VIII family metal is Ni, and Ib family metal is Cu, just can relax the stress that the displacement when driving produces with this, and can form thermal endurance and the good described internal electrode of heat conductivity.

And then, in multi-layer piezoelectric element of the present invention, be preferably described internal electrode and include the space, be 5～70% with respect to area ratio whole sectional area, that the space is occupied in the cross section of described internal electrode.If like this, just can weaken piezoelectrics because of the restraining force that because of internal electrode cause of electric field when being out of shape, thereby can increase the addendum modification of piezoelectrics.Again, following advantage is arranged: the stress that puts in the internal electrode relaxes because of the space, thereby the durability of element improves.And then, in the heat conduction in element, internal electrode plays the mastery effect, but if the space is arranged in internal electrode, then can relax the variations in temperature of the element internal that the rapid variations in temperature because of element-external causes, so can access the strong element of opposing thermal shock ability.

According to the multi-layer piezoelectric element of the present invention of above formation, just can provide can be under the environment under high voltage, the high pressure long-time continuous multi-layer piezoelectric element that drive, good endurance.

Description of drawings

Figure 1A is the stereogram of the structure of expression multi-layer piezoelectric element of the present invention;

Figure 1B is the exploded perspective view that decomposes the part of ground presentation graphs 1A;

Fig. 2 is the stereogram of the existing multi-layer piezoelectric element of expression;

Fig. 3 is the profile of expression injection apparatus of the present invention;

Fig. 4 A is the stereogram of structure of the multi-layer piezoelectric element of expression embodiments of the present invention ten;

Fig. 4 B is the profile of the A-A ' line of Fig. 4 A.

Symbol description

1,11 piezoelectrics

1a, 13 laminates

2,12 internal electrodes

3 insulators

5 leads

4,15 outer electrodes

6,14 inertia portions

7 conductivity accessories

31 accommodating containers

33 spray-holes

35 valves

43 piezo-activators

Embodiment

Below describe the multi-layer piezoelectric element of embodiments of the present invention in detail.

Figure 1A is the stereogram of structure of the multi-layer piezoelectric element of expression embodiments of the present invention.Again, Figure 1B is the exploded perspective view that decomposes the part of ground presentation graphs 1A, the lamination state of expression piezoelectric body layer 11 and interior electrode layer 12.

The multi-layer piezoelectric element of embodiments of the present invention, shown in Figure 1A, 1B, on a pair of opposed side of the laminate 13 that lamination piezoelectrics alternately 11 and internal electrode 12 form, the end of internal electrode 12 every one deck be engaged on the outer electrode 15 that conducts.

Promptly, make laminate in such a way: the internal electrode of the side in 2 internal electrodes of (1) adjacency exposes its end on a side's who is formed with outer electrode side, the opposing party's internal electrical extremely end is not exposed from a side side but is positioned at the inboard, (2) internal electrode its end on the opposing party's who is formed with another outer electrode side of the side in 2 of this adjacency internal electrodes is not exposed but is positioned at the inboard, and the opposing party's internal electrical extremely end is exposed from the opposing party's side; On a side's of this laminate side and the opposing party's side, be formed with outer electrode 15 respectively.With this, be formed with on each side of outer electrode, the end of internal electrode 12 every one deck be linked on the outer electrode 15.

Be provided with at the two ends of the lamination direction of laminate 13 that a lamination has piezoelectrics 11 and the inert layer that do not have internal electrode again.At this, under the situation that the multi-layer piezoelectric element with present embodiment uses as the stack-up type piezo-activator, utilize scolding tin that lead is connected and fixed on the outer electrode 15, described lead is connected on the external voltage supply unit gets final product again.

In the multi-layer piezoelectric element of the execution mode of above formation, the voltage of regulation puts on each piezoelectrics 11 through internal electrode 12, thereby causes the displacement that produces because of reciprocal piezoelectric effect in piezoelectrics 11.

With respect to this, because inert layer 14 is the layers that do not dispose a plurality of piezoelectrics 11 of internal electrode 12, so also do not produce displacement even apply voltage.

Below, describe the embodiments of the present invention in detail.

Execution mode one

The multi-layer piezoelectric element of embodiments of the present invention one, the alkali metal in the piezoelectrics 11 is below the above 500ppm of 5ppm.Under the situation below the 5ppm, function as sintering adjuvant reduces significantly, if do not improve the sintering that sintering temperature then can not be carried out piezoelectrics, so when forming laminate 13, can produce this problem of internal electrode metal melting, so be not preferred.Again, as if surpassing 500ppm, then under the situation of Continuous Drive multi-layer piezoelectric element, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the alkali metal that makes in the piezoelectrics 11 below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the alkali metal that makes in the piezoelectrics 11 below the above 50ppm of 5ppm.

Then, illustrate that below making alkali metal in piezoelectrics is the manufacture method of above-mentioned scope.

Promptly, for the alkali-metal one-tenth of controlling in the piezoelectrics 11 is grouped into, add alkali metal, sneak into this manufacture method of alkali metal as unavoidable impurities and just can realize by constituent in the raw material of piezoelectrics 11 and binder materials, but be not limited thereto as oxide, carbonate or nitrate etc.In addition, because in manufacturing process, alkali metal is sneaked into or is spread from sintering atmosphere gas from the crushing ball of raw material that mix to pulverize piezoelectrics 11, so under the alkali-metal situation in the control multi-layer piezoelectric element, in order to prevent that coming from the alkali-metal of manufacturing process sneaks into, following method also can: make other goods and manufacturing process independent, being grouped into the alkali-metal one-tenth that becomes unavoidable impurities in the control raw material is that the mode of amount of alkali metal oxide or alkali carbonate, nitrate makes an addition to it in raw material.

Execution mode two

The multi-layer piezoelectric element of embodiments of the present invention two, the alkali metal in the internal electrode 12 is below the above 500ppm of 5ppm.When 5ppm is following, reduce significantly as the function of sintering adjuvant, if not improving sintering temperature then can not carry out the sintering of internal electrode 12, so be not preferred.Again, if surpass 500ppm, then multi-layer piezoelectric element is being applied under the situation of high-tension DC electric field, alkali metal ion is diffused into piezoelectrics 11 from becoming anodal internal electrode 12, thereby has reduced the resistance value of piezoelectrics 11, consequently, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the alkali metal that makes in the internal electrode below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the alkali metal that makes in the internal electrode below the above 50ppm of 5ppm.

Then, illustrate that below making alkali metal in internal electrode is the manufacture method of above-mentioned scope.

Promptly, for the alkali-metal one-tenth of controlling in the internal electrode 12 is grouped into, add alkali metal, sneak into this manufacture method of alkali metal as unavoidable impurities and just can realize by constituent in the raw material of internal electrode 12 and binder materials, but be not limited thereto as oxide or carbonate, nitrate etc.In addition, because in manufacturing process, alkali metal is sneaked into or is spread from sintering atmosphere gas from the crushing ball of raw material that mix to pulverize internal electrode 12, so under the alkali-metal situation in the control multi-layer piezoelectric element, in order to prevent that coming from the alkali-metal of manufacturing process sneaks into, following method also can: making other goods and manufacturing process independent, is that the mode of amount of alkali metal oxide or alkali carbonate, nitrate makes an addition to it in raw material to suppress that the alkali-metal one-tenth that becomes unavoidable impurities in the control raw material is grouped into.

Execution mode three

The multi-layer piezoelectric element of embodiments of the present invention three, the alkali metal in the outer electrode 15 is below the above 500ppm of 5ppm.When 5ppm is following, function as sintering adjuvant reduces significantly, if do not improve the sintering that sintering temperature then can not be carried out outer electrode 15, so when sintering, can produce this problem of metal melting of internal electrode 12, and, the auxiliary power of connecting airtight of piezoelectrics 11 is reduced, so be not preferred.Again, if surpass 500ppm, then multi-layer piezoelectric element is being applied under the situation of high-tension DC electric field, alkali metal ion is diffused into piezoelectrics 11 from becoming anodal outer electrode 15, thereby has reduced the resistance value of piezoelectrics 11, consequently, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the alkali metal that makes in the outer electrode below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the alkali metal that makes in the outer electrode below the above 50ppm of 5ppm.

Then, illustrate below that externally making alkali metal in the electrode is the manufacture method of above-mentioned scope.

Promptly, for the alkali-metal one-tenth of controlling in the outer electrode 15 is grouped into, constituent as oxide or carbonate, nitrate etc. in raw material by electrode 15 externally and the binder materials adds alkali metal, sneak into this manufacture method of alkali metal as unavoidable impurities just can realize, but is not limited thereto.In addition, because in manufacturing process, alkali metal is sneaked into or is spread from sintering atmosphere gas from the crushing ball of raw material that mix to pulverize outer electrode 15, so under the alkali-metal situation in the control multi-layer piezoelectric element, in order to prevent that coming from the alkali-metal of manufacturing process sneaks into, following method also can: making other goods and manufacturing process independent, is that the mode of amount of alkali metal oxide or alkali carbonate, nitrate makes an addition to it in raw material to suppress that the alkali-metal one-tenth that becomes unavoidable impurities in the control raw material is grouped into.

Execution mode four

The multi-layer piezoelectric element of embodiments of the present invention four, the alkali metal in the multi-layer piezoelectric element is below the above 300ppm of 5ppm.When 5ppm is following, reduce significantly as the function of sintering adjuvant, if not improving sintering temperature then can not carry out the sintering of laminate 13, so be not preferred.Again, as if surpassing 300ppm, then under the situation of Continuous Drive multi-layer piezoelectric element, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.Particularly,, be preferably the alkali metal that makes in the multi-layer piezoelectric element below the above 100ppm of 5ppm, more preferably make alkali metal below the above 50ppm of 5ppm for the rate of change of the variable quantity that makes the multi-layer piezoelectric element in the Continuous Drive is little.

Then, illustrate that below making alkali metal in multi-layer piezoelectric element is the manufacture method of above-mentioned scope.

Promptly, for the alkali-metal one-tenth of controlling in the existing multi-layer piezoelectric element is grouped into, add alkali metal, sneak into this manufacture method of alkali metal as unavoidable impurities and just can realize by constituent in the raw material separately of piezoelectrics 11, internal electrode 12 and outer electrode 15 and binder materials, but be not limited thereto as oxide or carbonate, nitrate etc.In addition, because in manufacturing process, alkali metal is sneaked into or is spread from sintering atmosphere gas from the crushing ball of raw material that mix to pulverize piezoelectrics 11, so under the alkali-metal situation in the control multi-layer piezoelectric element, in order to prevent that coming from the alkali-metal of manufacturing process sneaks into, following method also can: make other goods and manufacturing process independent, being grouped into the alkali-metal one-tenth that becomes unavoidable impurities in the control raw material is that the mode of amount of alkali metal oxide or alkali carbonate, nitrate makes an addition to it in raw material.

In above execution mode one to four, alkali-metal amount can detect as follows: in piezoelectrics 11, internal electrode 12, outer electrode, cut off after the multi-layer piezoelectric element, selectivity such as use etching technique stay position separately, then with the piezoelectrics that separate, internal electrode, outer electrode as sample, detect by the ICP luminesceence analysis.When the alkali-metal amount that detects multi-layer piezoelectric element, can detect by the ICP luminesceence analysis with multi-layer piezoelectric element as sample again.Again, as detection method, being not limited to the ICP luminesceence analysis, is equal if detect the lower limit of boundary, then also can use analytical methods such as Auger spectroscopy analysis method or EPMA (electron probe micro-analysis) method.

As alkali metal of the present invention, be preferably among Na, the K at least a more than.Lithium, sodium, potassium, rubidium, caesium, francium are arranged in alkali metal, but Na, K being because be easy ionization, the easy alkali metal of migration, is preferred so reduce, reduce on the addendum modification of multi-layer piezoelectric element at the component resistance that makes multi-layer piezoelectric element.

Execution mode five

The multi-layer piezoelectric element of embodiments of the present invention five, the halogens in the piezoelectrics is below the above 1500ppm of 5ppm.When 5ppm is following, reduce significantly as the function of sintering adjuvant, if do not improve the sintering that sintering temperature then can not be carried out piezoelectrics, so when forming laminate 13, can produce this problem of internal electrode metal melting, so be not preferred.Again, if surpass 1500ppm, then under the situation of Continuous Drive multi-layer piezoelectric element, the intrinsic resistance of element changes, and just change with this addendum modification, thereby device causes misoperation, perhaps causes short circuit and drives and stop, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the halogens that makes in the piezoelectrics below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the halogens that makes in the piezoelectrics below the above 50ppm of 5ppm.

Then, illustrate that below making halogens in piezoelectrics is the manufacture method of above-mentioned scope.

Promptly, for the one-tenth of controlling the halogens in the piezoelectrics 11 is grouped into, by in the raw material of piezoelectrics 11 and binder materials, adding halogens, sneak into this manufacture method of halogens as unavoidable impurities and just can realize, but be not limited thereto as fluoride, chloride, bromide, iodide or astatine compound.On the other hand, in addition, because in manufacturing process, halogens is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 11, perhaps spread from the sintering atmosphere, so under the situation of the halogens in the control multi-layer piezoelectric element, for sneaking into of the halogens that prevents to come from manufacturing process, following method also can: make other goods and manufacturing process independent, being grouped into the one-tenth that suppresses the halogens that becomes unavoidable impurities in the control raw material is fluoride, chloride, bromide, the mode of iodide or astatine compound is controlled the amount of halogens.

Execution mode six

The multi-layer piezoelectric element of embodiments of the present invention six, the halogens in the internal electrode is below the above 1500ppm of 5ppm.When 5ppm is following, reduce significantly as the function of sintering adjuvant, if not improving sintering temperature then can not carry out the sintering of internal electrode, so be not preferred.Again, if surpass 1500ppm, then multi-layer piezoelectric element is being applied under the situation of high-tension DC electric field, the halogens ion is diffused into piezoelectrics 11 from the internal electrode 12 that becomes negative pole, thereby has reduced the resistance value of piezoelectrics 11, consequently, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the halogens that makes in the internal electrode below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the halogens that makes in the internal electrode below the above 50ppm of 5ppm.

Then, illustrate that below making halogens in internal electrode is the manufacture method of above-mentioned scope.

Promptly, for the one-tenth of controlling the halogens in the internal electrode 12 is grouped into, by in the raw material of internal electrode 12 and binder materials, adding halogens, sneak into this manufacture method of halogens as unavoidable impurities and just can realize, but be not limited thereto as fluoride, chloride, bromide, iodide or astatine compound.On the other hand, in addition, because in manufacturing process, halogens is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 11, perhaps from sintering atmosphere gas, spread, so under the situation of the halogens in the control multi-layer piezoelectric element, for sneaking into of the halogens that prevents to come from manufacturing process, following method also can: make other goods and manufacturing process independent, being grouped into the one-tenth that suppresses the halogens that becomes unavoidable impurities in the control raw material is fluoride, chloride, bromide, the mode of iodide or astatine compound is controlled the amount of halogens.

Execution mode seven

The multi-layer piezoelectric element of embodiments of the present invention seven, the halogens in the outer electrode is below the above 500ppm of 5ppm.Below 5ppm, reduce significantly as the function of sintering adjuvant, if do not improve the sintering that sintering temperature then can not be carried out outer electrode, thus when sintering, can produce this problem of internal electrode metal melting, so be not preferred.And then, because connecting airtight power, diminish adhering on piezoelectrics 11, so be not preferred.Again, if surpass 500ppm, then multi-layer piezoelectric element is being applied under the situation of high-tension DC electric field, halide ion is diffused into piezoelectrics 11 from the outer electrode 15 that becomes negative pole, thereby has reduced the resistance value of piezoelectrics 11, consequently, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.

Particularly, for the rate of change that makes the component variation amount in the Continuous Drive is little, be preferably the halogens that makes in the outer electrode below the above 100ppm of 5ppm.

And then, for the rate of change that makes the component variation amount is little, be preferably the halogens that makes in the outer electrode below the above 50ppm of 5ppm.

Then, illustrate below that externally making halogens in the electrode is the manufacture method of above-mentioned scope.

Promptly, for the one-tenth of controlling the halogens in the outer electrode 15 is grouped into, add halogens, sneak into this manufacture method of halogens as unavoidable impurities and just can realize as fluoride, chloride, bromide, iodide or astatine compound in raw material by electrode 15 externally and the binder materials, but be not limited thereto.On the other hand, in addition, because in manufacturing process, halogens is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 11, perhaps spread from the sintering atmosphere, so under the situation of the halogens in the control multi-layer piezoelectric element, for sneaking into of the halogens that prevents to come from manufacturing process, following method also can: make other goods and manufacturing process independent, being grouped into the one-tenth that suppresses the halogens that becomes unavoidable impurities in the control raw material is fluoride, chloride, bromide, the mode of iodide or astatine compound is controlled the amount of halogens.

Execution mode eight

The multi-layer piezoelectric element of embodiments of the present invention eight, the halogens in the multi-layer piezoelectric element is below the above 300ppm of 5ppm.When 5ppm is following, reduce significantly as the function of sintering adjuvant, if not improving sintering temperature then can not carry out the sintering of laminate 13, so be not preferred.Again, as if surpassing 300ppm, then under the situation of Continuous Drive multi-layer piezoelectric element, the intrinsic resistance of element changes, just change with this addendum modification, thus the error action of device work, so be not preferred.Particularly,, be preferably the halogens that makes in the multi-layer piezoelectric element below the above 100ppm of 5ppm, more preferably make alkali metal below the above 50ppm of 5ppm for the rate of change of the variable quantity that makes the multi-layer piezoelectric element in the Continuous Drive is little.

Then, illustrate that below making alkali metal in multi-layer piezoelectric element is the manufacture method of above-mentioned scope.Promptly, for the one-tenth of controlling the halogens in the existing multi-layer piezoelectric element is grouped into, by in the raw material separately of piezoelectrics 11, internal electrode 12 and outer electrode 13 and binder materials, adding halogens, sneak into this manufacture method of halogens as unavoidable impurities and just can realize, but be not limited thereto as fluoride, chloride, bromide, iodide or astatine compound.On the other hand, in addition, because in manufacturing process, halogens is sneaked into from the crushing ball that mixes the raw material of pulverizing piezoelectrics 11, perhaps from sintering atmosphere gas, spread, so under the situation of the halogens in the control multi-layer piezoelectric element, for sneaking into of the halogens that prevents to come from manufacturing process, following method also can: make other goods and manufacturing process independent, being grouped into the one-tenth that suppresses the halogens that becomes unavoidable impurities in the control raw material is fluoride, chloride, bromide, the mode of iodide or astatine compound is controlled the amount of halogens.

In above execution mode five to eight, the amount of halogens can detect as follows: in piezoelectrics, internal electrode, outer electrode, cut off after the multi-layer piezoelectric element, use etching technique etc. in the mode that separately position selectively stays, then with the piezoelectrics that separate, internal electrode, outer electrode as sample, detect by the chromatography of ions.When the amount of the halogens that detects multi-layer piezoelectric element, can detect by the chromatography of ions with multi-layer piezoelectric element as sample again.Again, as detection method, being not limited to the chromatography of ions, is ad eundem if detect the lower limit of boundary, then also can use the analytical method of Auger spectroscopy analysis method or EPMA (electron probe micro-analysis) method etc.

Again, more preferably to make alkali metal in multi-layer piezoelectric element be below the above 300ppm of 5ppm and make halogens is below the above 1000ppm of 5ppm.With this, different with above-mentioned effect, can prevent with the silver migration to be the diffusion of the electrode formation metallic element of representative.

In addition, as the halogens that is used among the present invention, be preferably use among Cl, the Br at least a more than.Fluorine, chlorine, bromine, iodine, astatine are arranged in halogens, but Cl, Br being because be easy ionization, the easy alkali metal of migration, is preferred so reduce, reduce on the addendum modification of multi-layer piezoelectric element at the component resistance that makes multi-layer piezoelectric element.

By making the alkali metal that is contained in the multi-layer piezoelectric element of the present invention or halogens in above-mentioned scope, just can make the heat that produces in Continuous Drive is uniform temperature, and addendum modification is remained necessarily.

Like this, in order to suppress heating,, also must reduce the dielectric loss (tan δ) of piezoelectrics 11, perhaps reduce component resistance except stipulating the containing the scope of above-mentioned impurity because of the multi-layer piezoelectric element self that drive to produce.

Execution mode nine

In the multi-layer piezoelectric element of embodiment of the present invention nine, the rate of change of the component size before and after the Continuous Drive of multi-layer piezoelectric element is in 1%.This be because, if the rate of change of the component size before and after the Continuous Drive of multi-layer piezoelectric element surpasses 1%, then the variation of the addendum modification of multi-layer piezoelectric element increases, thus multi-layer piezoelectric element destroys because of thermal runaway.

At this, the rate of change of the component size before and after the Continuous Drive is represented: multi-layer piezoelectric element is being applied alternating voltage, 1 * 10 arbitrarily ⁹Size on the lamination direction of the multi-layer piezoelectric element after the Continuous Drive of the inferior left and right sides is with respect to the size of the multi-layer piezoelectric element before the Continuous Drive and the ratio that changes.

Again, in multi-layer piezoelectric element of the present invention, the rate of change of the gauge of the internal electrode 12 before and after the Continuous Drive of multi-layer piezoelectric element is in 5%.This be because, if the rate of change of the gauge of the internal electrode 12 before and after the Continuous Drive of multi-layer piezoelectric element surpasses 5%, then the deterioration of the multi-layer piezoelectric element of representing with the rate of change of the addendum modification of multi-layer piezoelectric element increases, thereby the durability of multi-layer piezoelectric element significantly reduces.

At this, the rate of change of the gauge of the internal electrode before and after the Continuous Drive is represented: multi-layer piezoelectric element is being applied alternating voltage, 1 * 10 arbitrarily ⁹The gauge of the internal electrode on the lamination direction of the multi-layer piezoelectric element after the Continuous Drive of the inferior left and right sides is with respect to the gauge of the internal electrode before the Continuous Drive and the ratio that changes.In addition, in multi-layer piezoelectric element, dispose under the situation of 5 above internal electrodes 12, the gauge of internal electrode is following to be obtained: with SEM measure the internal electrode 12 (2 positions) that joins with inert layer 14, the internal electrode 12 (1 position) of the centre of the lamination direction that is positioned at multi-layer piezoelectric element, in addition be disposed at the internal electrode 12 that is positioned at this centre with and the internal electrode 12 that joins of described inert layer 14 in the middle of the gauge of internal electrode arbitrarily 12 (2 positions), get its mean value then.During 5 of internal electrode 12 less thaies on being disposed at multi-layer piezoelectric element, measure the gauge of all internal electrodes 12, with the gauge of its mean value as internal electrode.

In the multi-layer piezoelectric element of execution mode nine,, must prevent the volumetric expansion that the oxidation because of internal electrode 12 causes for the rate of change of the gauge of controlling component size before and after the Continuous Drive or internal electrode 12.At this, make with the following method and get final product in order to suppress described volumetric expansion.

Up to the present, as the method for the variation of the gauge that suppresses component size before and after the Continuous Drive or internal electrode, can use the component temperature in the Continuous Drive is remained certain method or comes controlling and driving voltage method meticulously corresponding to component temperature.Particularly, while monitor component temperature controlling and driving voltage, perhaps the radiator that dispels the heat on one's own initiative is installed for the control element peripheral temperature.

With respect to this, in present embodiment nine,, control the component temperature in the Continuous Drive by the heating of the element self that suppresses to produce because of driving.In order to control described component temperature, must reduce the dielectric loss (tan δ) of piezoelectrics 11, perhaps reduce component resistance.

For the dielectric loss (tan δ) that reduces piezoelectrics 11, with PbZrO ₃-PbTiO ₃Deng perofskite type oxide is that principal component forms under the situation of piezoelectrics 11, and the method for sintering laminate 13 under the excessive atmosphere gas of oxygen is arranged, and perhaps in the processing behind the sintering of laminate 13, makes from the slower method of the cooling rate of maximum sintering temperature.Particularly, making cooling rate is to get final product below 600 ℃/hour, is preferably below 300 ℃/hour.Again, as the value of dielectric loss (tan δ), less than 1.5% gets final product, and is preferably below 0.5%.

Again, in order to reduce component resistance, in internal electrode 12, use the material of the composition littler, and the structure of doing to become the densification in the path of guaranteeing conductivity gets final product than resistance value.

And then, because it is irrelevant and certain to be preferably the temperature characterisitic of the addendum modification that constituent material had and the serviceability temperature of piezoelectrics 11, so preferably change the little piezoelectrics material of addendum modification with respect to the component temperature in the Continuous Drive.

For the heat with element internal is discharged into outside the element efficiently, is preferably the internal electrode 12 that makes heat transfer and is the good composition of heat conductivity again.

And then the metal constituent that is preferably in the internal electrode 12 is a principal component with VIII family metal and/or Ib family metal.This is because above-mentioned metal constituent has high-fire resistance, so also can the high piezoelectrics 11 and internal electrode 12 of while sintering sintering temperature.

And then, the metal constituent that is preferably in internal electrode 12 is a principal component with following metal constituent: at the amount of VIII family metal is that the amount of M1 (% weight), Ib family metal is when being M2 (% weight), satisfy 0＜M1≤15,85≤M2＜100, M1+M2=100.This is because if VIII family metal surpasses 15% weight, then the ratio resistance of internal electrode 12 becomes big, thereby under the situation of Continuous Drive multi-layer piezoelectric element, the situation of internal electrode 12 heatings is arranged.In order to suppress the migration of Ib family metal on piezoelectrics 11 in the internal electrode 2, be preferably VIII family metal below 15% weight more than 0.001% weight again.On the durability this point that improves multi-layer piezoelectric element, be preferably below above 10% weight of 0.1% weight again.Again, under good, the higher durability of heat conductivity is necessary situation, more preferably below above 9.5% weight of 0.5% weight.Again, under the situation of pursuing higher durability, more preferably below above 8% weight of 2% weight.

At this, because if Ib family metal less than 85% weight, then the ratio resistance of internal electrode 12 becomes big, under the situation of Continuous Drive multi-layer piezoelectric element, the situation of internal electrode 12 heatings is arranged.In order to suppress the migration of Ib family metal on piezoelectrics 11 in the internal electrode 12, be preferably Ib family metal below 99.999% weight more than 85% weight again.On the durability this point that improves multi-layer piezoelectric element, be preferably below above 99.9% weight of 90% weight again.Under higher durability is necessary situation, be preferably below above 99.5% weight of 90.5% weight again.Again, under the situation of pursuing higher durability, more preferably below above 98% weight of 92% weight.

The VIII family metal of the % weight of the expression metal ingredient in the above-mentioned internal electrode 12, Ib family metal can use the analytical method of EPMA (electron probe micro-analysis) method etc. to come specific.

And then, the metal ingredient in the internal electrode 12 of the present invention be preferably VIII family metal be among Ni, Pt, Pd, Rh, Ir, Ru, the Os at least a more than, Ib family metal be among Cu, Ag, the Au at least a more than.This is because they are to form at the good metal of alloy powder synthetic technology medium quantity batch processing in recent years.

And then, the metal ingredient in the internal electrode 12 be preferably VIII family metal be among Pt, the Pd at least a more than, Ib family metal be among Ag, the Au at least a more than.With this, the possibility that can form good heat resistance, the internal electrode 12 littler than resistance is just arranged.

And then it is Ni that the metal ingredient in the internal electrode 12 is preferably VIII family metal, and Ib family metal is Cu.With this, just can form the good internal electrode of thermal endurance and heat conductivity 12.

And then, be preferably and in internal electrode 12, add metal constituent and inorganic composition.With this, just connecting inner electrode 12 and piezoelectrics 11 securely, described inorganic composition are preferably with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component.

And then being preferably piezoelectrics 11 is principal component with the perofskite type oxide.This be because, for example, if in order to barium titanate (BaTiO ₃) be the formation piezoelectrics 11 such as Ca-Ti ore type piezoceramic material of representative, then represent the piezoelectricity distortion constant d of its piezoelectric property ₃₃Height, thus can make addendum modification big, and then, side by side sintering piezoelectrics 11 and internal electrode 12.Be preferably with piezoelectricity distortion constant d as the piezoelectrics 11 shown in above-mentioned ₃₃Than higher, by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component.

And then, be preferably sintering temperature more than 900 ℃ below 1000 ℃.This be because, sintering temperature below 900 ℃ the time, so because the low sintering of sintering temperature is insufficient, thereby be difficult to make fine and close piezoelectrics 11.Again, if sintering temperature surpasses 1000 ℃, the deviation of the contraction of the internal electrode 12 during then by sintering and the contraction of the piezoelectrics 11 and stress that causes becomes greatly, thus the possibility that cracks when the Continuous Drive of multi-layer piezoelectric element is arranged.

Again, the deviation that is preferably the composition in the internal electrode 12 is below 5% before and after sintering.This be because, if the deviation of the composition in the internal electrode 12 surpasses 5% before and after sintering, then the migration of the metal material in the internal electrode 12 on piezoelectrics 11 becomes many, thereby has internal electrode 12 can not follow the flexible possibility that the driving because of multi-layer piezoelectric element causes.

At this, the rate of change that the element that the deviation of the composition in the internal electrode 12 represents to constitute internal electrode 12 evaporates by sintering or the composition of internal electrode 12 changes by diffusion on piezoelectrics 11.

Again, be preferably, the internal electrode 12 that does not expose internal electrode 12 and the end that expose on the side of multi-layer piezoelectric element end of the present invention alternately constitutes, be formed with groove on internal electrode 12 that does not expose in described end and the part of the piezoelectrics between the outer electrode 15, in this groove, be formed with than the low insulator of piezoelectrics 11 Young's moduluss.With this, in such multi-layer piezoelectric element, because can relax the stress that produces because of the displacement in driving, so even Continuous Drive also can suppress the heating of internal electrode 12.

The manufacture method of the multi-layer piezoelectric element of present embodiment one to nine then, is described.

In this manufacture method, at first, mix by PbZrO ₃-PbTiO ₃Deng the powders calcined of the piezoelectric ceramic of the perofskite type oxide that constitutes, with the adhesive that constitutes by organic polymers such as propylene system, butyral systems, and DBP (dibutyl phthalate), DOP plasticizer such as (dioctyl phthalates), make slurry, utilize the well-known band methods of forming such as the skill in using a kitchen knife in cookery or stack method of scraping this slurry to be made as the ceramic green sheet that constitutes piezoelectrics 11.

Then, in the metal dust of formation internal electrodes such as silver-palladium, add mixed adhesive, plasticizer, make conductive paste, it is printed the thickness of 1～40 μ m on the upper surface of described each raw cook by screen printing etc.

And the lamination multi-disc is printed with the raw cook of conductive paste on upper surface, and after under the temperature of regulation, this laminate being carried out the unsticking mixture, by making laminate 13 at 900～1200 ℃ of following sintering.Be preferably as described above, in 900～1000 ℃ scope, carry out sintering.

In addition, laminate 13 is not limited to by the said method manufacturing, if can make alternately lamination multi-disc piezoelectrics 11 and the laminate 13 that multi-disc internal electrode 12 forms, then forms by arbitrary method and all can.

Thereafter, alternately be formed on the internal electrode 12 that does not expose the internal electrode 12 that the upper end, side of multi-layer piezoelectric element exposes and end, form groove on internal electrode 12 that does not expose in the end and the part of the piezoelectrics between the outer electrode 15, in this groove, form than piezoelectrics 11 Young's moduluss low, insulators such as resin or rubber.At this, described groove is formed at the side of laminate 13 with inner cutter sweep etc.

Outer electrode 15 absorbs the flexible stress this point consideration that produces because of actuator fully from the electric conducting material that constitutes, and it is preferably the low silver of Young's modulus or is the alloy of principal component with silver.

In glass powder, add adhesive and make silver-colored glass conductive paste, this conductive paste is formed tabular, and the green density of the dry plate that (solvent is dispersed) is controlled to be 6～9g/cm ³This plate is transferred on the outer electrode formation face of column laminate 13, and the temperature higher and the temperature below the silver point (965 ℃) and sintering temperature than the softening point of glass (℃) the temperature below 4/5 under carry out sintering, use the disappearance of just dispersing of adhesive ingredients in the plate that silver-colored glass conductive paste is made into this, thereby can form the outer electrode 15 that constitutes by the porous matter electric conductor that constitutes the three-dimensional network structure.

In addition, thereby silver and internal electrode 12 from form neck diffusion bond silver glass conductive paste effectively, space in the residual effectively again outer electrode 15 and then partly engage outer electrode 15 and column laminate 13 sides these are put and consider that the sintering temperature of described silver-colored glass conductive paste is preferably 550～700 ℃.Again, the softening point of the glass ingredient in the silver-colored glass conductive paste is preferably 500～700 ℃.

Sintering temperature than 700 ℃ of high situations under, exceedingly carried out the sintering of the silver powder of silver-colored glass conductive paste, can not form the porous matter electric conductor that constitutes effective three-dimensional network structure, it is too fine and close that thereby outer electrode 15 becomes, consequently the Young's modulus of outer electrode 15 becomes too high, can not absorb the stress when driving fully, thereby the possibility of outer electrode 15 broken strings is arranged.Be preferably at the softening point of glass 1.2 times and carry out sintering under with interior temperature.

On the other hand, sintering temperature than 550 ℃ of low situations under, because can not between internal electrode 12 and outer electrode 15, form diffusion bond fully, thus neck can not be formed, thus the possibility that causes spark when driving between internal electrode 12 and outer electrode 15 is arranged.

In addition, the thickness of the plate of silver-colored glass conductive paste is preferably the thin thickness than piezoelectrics 11.Consider from the flexible this point of following actuator, more preferably below the 50 μ m.

Then, the laminate 13 that will be formed with outer electrode 15 impregnated in the silicone rubber solution, and silicone rubber solution is carried out vacuum degassing, silicon rubber filling is arrived the groove inside of laminate 13 with this, from silicone rubber solution pull out laminate 13, at the side of laminate 13 coating silicon rubber thereafter.Thereafter, solidify by making the described silicon rubber on the side that is filled in groove inside and is coated on column laminate 13, multi-layer piezoelectric element of the present invention has just been finished.

Then, lead is connected on the outer electrode 15, utilize this lead pair of external electrodes 15 to be applied the direct voltage of 0.1～3kV/mm, to laminate 13 processing that polarizes, utilized the stack-up type piezo-activator of multi-layer piezoelectric element of the present invention just to finish with this, if lead is connected on the outside voltage supply unit, utilize lead and outer electrode 15 to come internal electrode 12 is applied voltage, then each piezoelectrics 11 utilizes reciprocal piezoelectric effect to come displacement significantly, just for example is supplied in the automotive fuel injection valve of engine and brings into play its function as fuel is sprayed with this.

And then, externally be formed with the conductivity accessory that the conductive adhesive by net that is embedded with metal or cancellous metallic plate constitutes on the outer surface of electrode 15 and also can.Under this situation, by the outer surface of electrode 15 externally the conductivity accessory is set, even in actuator, have high input under electric current, the situation with high-speed driving, electric current is flow in the conductivity accessory, thereby can reduce the electric current that flow in the outer electrode 15, thereby consider from this reason, thereby can prevent that outer electrode 15 from causing the local overheating broken string, thus durability can be improved significantly.And then, because in conductive adhesive, be embedded with the net or the cancellous metallic plate of metal, can prevent from described conductive adhesive, to crack.

The net of metal is braided metal line and the net that obtains, and cancellous metallic plate is to form the hole on metallic plate, make to become cancellous metallic plate.

And then the conductive adhesive that constitutes described conductivity accessory is preferably by the polyimide resin that is dispersed with silver powder and constitutes.That is, be scattered in the high polyimide resin of thermal endurance,, also can form lower and kept the conductivity accessory of high-adhesive-strength than resistance even when the use at high temperature by making the silver powder lower than resistance.More preferably, described electroconductive particle is lamellar or nonspherical particle such as needle-like.This is because by making aspheric particle such as the lamellar or needle-like of being shaped as of electroconductive particle, just can make the polymerization between this electroconductive particle firm, thereby can further improve the shear strength of this conductive adhesive.

Multi-layer piezoelectric element of the present invention is not limited to above-mentioned each multi-layer piezoelectric element, can carry out all changes in the scope that does not break away from main idea of the present invention.

Again, the example that forms outer electrode 15 on the opposed side of laminate 13 has been described above, but in the present invention, for example also can in formation pair of external electrodes 15 on the side that is provided with.

Execution mode ten

Fig. 4 A is the stereogram of the multi-layer piezoelectric element (stack-up type piezo-activator) of embodiment of the present invention ten.Again, Fig. 4 B is the profile of the A-A ' line of Fig. 4 A.

As shown in Figure 4, the stack-up type piezo-activator of present embodiment ten is following structure: on the side of the column laminate 1a of the square column that lamination multi-disc piezoelectrics alternately 1 and multi-disc internal electrode 2 form, coat the end of internal electrode 2 with insulator 3 every one deck ground, engaging on the end of the internal electrode 2 that does not coat with insulator 3 has by by being that the electric conducting material of principal component constitutes and constitute the outer electrode 4 that porous matter electric conductor that three-dimensional network constructs constitutes with glass with silver, is fixedly connected with lead 5 on each outer electrode 4.In addition, symbol 6 is inert layers.

And piezoelectrics 1 form with the PZT series piezoelectric ceramic material that describes in detail later.This piezoelectric ceramic is preferably the piezoelectricity distortion constant d of its piezoelectric property of expression ₃₃High.

Again, the thickness of piezoelectrics 1 is that the distance of 2 of internal electrodes is preferably 50～250 μ m.With this, though in order to apply voltage so that the stack-up type piezo-activator obtains bigger addendum modification and increases the lamination number, also can realize miniaturization, the low level of actuator, and can prevent the insulation breakdown of piezoelectrics 1.

Configuration internal electrode 2 between piezoelectrics 1, the metal constituent of this internal electrode 2 is made of the periodic table of elements the 8th family's metal and Ib family metal.Being preferably described the 8th family's metal is to be made of at least a among Pt, the Pd, and Ib family metal is to be made of at least a among Au, the Ag.As example, can exemplify the Ag-Pd alloy.

When being M2 (%) as if the amount that at the amount that makes the 8th family's metal is M1 (%), Ib family metal, satisfy 0＜M1＜15,85＜M2＜100, cheap multi-layer piezoelectric element then can reduce the i.e. amount of Ib family metal of expensive material, so can be provided.But, if reduce the then fusing point reduction of alloying metal of amount of Ib family metal, so if not then can not use at the low sintering porcelain below 1000 ℃.The Si of not enough 1000ppm if in porcelain is formed, contain more than the 5ppm, then the crystal of porcelain is grown up easily, thus sintering under low temperature more easily.Again, if the Si amount of described scope does not then bring harmful effect to piezoelectric property.

Again, on the side of column laminate 1a, form the groove of width 30～200 μ n of the degree of depth 30～500 μ n, lamination direction every one deck ground, the glass that packing ratio piezoelectrics 1 Young's modulus is low in this groove, epoxy resin, polyimide resin, polyamide-imide resin, silicon rubber etc. form insulator 3.Firm with engaging of column laminate 1a in order to make, this insulator 3 is preferably by formations such as material, the particularly silicon rubber displacement of following column laminate 1a, that modulus of elasticity is low.

Engaging on the opposed side of column laminate 1a has outer electrode 4, on this outer electrode 4 every one deck be electrically connected with the internal electrode 2 of lamination.This outer electrode 4 functions as follows: will the necessary voltage common land of piezoelectrics 1 displacement be supplied on each internal electrode 2 that is connected for utilizing reciprocal piezoelectric effect.

And then, externally utilize scolding tin to be fixedly connected with lead 5 on the electrode 4.This lead 5 functions as follows: outer electrode 4 is connected to outside voltage supply unit.

And in the present invention, piezoelectric ceramic is characterised in that the piezoelectric ceramic that constitutes described piezoelectrics 1 is with PbTiO ₃-PbZrO ₃Be principal component, the Si amount is not enough 100ppm more than 5ppm.Si has the effect that improves porcelain intensity, if the Si amount of described scope, then Si is in the grain boundary segregation, thereby intercrystalline in conjunction with grow, so be difficult to threshing when adding man-hour or ultrasonic washing etc.Again, utilize the deterioration mechanism of volume intrinsic resistance, the deterioration that makes the grain boundary of bringing out because of DC electric field is known corresponding to the deterioration of porcelain.To have the resistivity higher than the inside of crystal grain be known in the grain boundary in piezoelectric ceramic, applying under the situation of DC electric field, and being polarized in of Maxwell-Wagner type produces highfield on the grain boundary.This electric field brings local insulation breakdown, with the volume intrinsic resistance deterioration of this porcelain.From above that consideration, if the Si amount more than 100ppm, then forms glassy phase in the grain boundary, so the resistivity on the grain boundary uprises, on the grain boundary, produce highfield, cause local destruction, so cause the deterioration of volume intrinsic resistance easily.If not enough 100ppm then can not form clear and definite glassy phase in the grain boundary, but as the SiO of unimolecule degree ₂And exist.Therefore, the resistivity step-down on the grain boundary, thus be difficult to cause local insulation breakdown.On the other hand, if the not enough 5ppm of the amount of Si, it is little then to improve this effect of intercrystalline adhesion, so easy threshing when adding man-hour or ultrasonic washing.

Again, piezoelectric ceramic of the present invention is following sintered body: the composition remainder in addition that is made of Si is made of perovskite-type compounds substantially; Constitute by perovskite-type compounds substantially at this remainder and to be meant, initiatively do not contain other composition in addition, beyond the impurity is perovskite-type compounds, if the composition (except the Si) that includes as impurity is in the scope of not enough 100ppm, even comprise also passable.

In the present invention, be preferably Si, and the thickness of the grain boundary layer of porcelain is below 1nm in the grain boundary segregation again.If the not enough 100ppm of Si amount, then Si is in the grain boundary segregation, and the thickness of grain boundary layer is below 1nm.With this, improved the intensity of porcelain, and then also hardly the characteristic of piezoelectricity distortion constant etc. exerted one's influence, thereby can make the volume intrinsic resistance through the time diminish.This is because if in the intragranular solid solution, then piezoelectric property significantly reduces as if Si, but in the grain boundary segregation, then can make for the influence of piezoelectricity distortion performance less.If the thickness of grain boundary layer surpasses 1nm, then on the grain boundary, form tangible glassy phase.If glassy phase is arranged on the grain boundary, then the resistance of grain boundary uprises, so cause small insulation breakdown easily on the grain boundary.Therefore, exist as glassy phase on the grain boundary with Si and to compare, should exist for the unimolecule degree by Si.

In order to improve mechanical strength, be preferably, the average crystal grain diameter A of piezoelectric ceramic is 0.5～5 μ m, when its standard deviation was B, B/A was below 0.5, and average aperture diameter C is 0.5～5 μ m, when its standard deviation is D, D/C is below 0.25, and is 5% when following in voidage, and opposing comes from outside impact or tired repeatedly ability grow.Again, leakage current increases sharp and reaches the breakdown mode of puncture, be well known that avalanche breakdown mode, but its reason is owing to the structure defective in crackle, space etc., so if the micro-structure of porcelain is even, then for example under situation about using as actuator, the volume intrinsic resistance during Continuous Drive through the time diminish, so can access high reliability.

If the change of the particle diameter of porcelain is greatly, the tendency that then has bending strength to reduce, if the average crystal grain diameter of porcelain surpasses 5 μ m, then easy impact or tired repeatedly destruction or the easy deterioration of volume intrinsic resistance because of coming from the outside, thus reliability reduces.On the contrary, consider, make the average crystal grain footpath less than 0.5 μ m of porcelain can cause difficulty on method for making from the micronize of raw material or the problem of sintering temperature.Therefore, the average crystal grain of porcelain directly is preferably 1～3 μ m.

Again, if the ratio B/A of the average crystal grain of porcelain footpath A and standard deviation B surpasses 0.5, then the micro-structure of porcelain is inhomogeneous, has bigger defective or crystal grain.Therefore, easily because of coming from outside impact or tired repeatedly destruction, the perhaps easy deterioration of volume intrinsic resistance.Because the average crystal grain of porcelain directly is 0.5～5 μ m, so the average diameter C in the space in the porcelain also becomes 0.5～5 μ m of equal extent.The more little opposing of defective come from outside impact or tired repeatedly ability just strong more, the volume intrinsic resistance just is difficult to deterioration more, so reliability improves.If the average grain diameter in space surpasses 5 μ m, then easily because of coming from outside impact or tired repeatedly destruction, so the perhaps easy deterioration of volume intrinsic resistance is the reliability reduction.On the other hand, consider, make the average diameter less than 0.5 μ m in space can cause being difficult to make at an easy rate from the micronize of raw material or the problem of sintering temperature.

Again,, then in porcelain, have bigger defective if the ratio D/C of average diameter C and its standard deviation D in the space in the porcelain surpasses 0.25, thus easily because of come from outside impact or repeatedly fatigue destroy.And then, too much if voidage surpasses 5% defective, so easily because of coming from outside impact or tired repeatedly destruction, so the perhaps easy deterioration of volume intrinsic resistance is the reliability reduction.Again, consider that it is preferred not having the space, but difficult on making from the aspect of characteristic or reliability.

The method for making of multi-layer piezoelectric element of the present invention is described.At first, make column laminate 1a.At first, as the material powder of PZT, highly purified PbO, the ZrO of weighing ormal weight ₂, TiO ₂, ZnO, Nb ₂O ₅, WO ₃, BaCO ₃, SrCO ₃, Yb ₂O ₃And SiO ₂Deng each material powder, with wet mixed such as ball mill 10～24 hours, then, after this mixture dehydration, drying, 800～900 ℃ of following roastings 1～3 hour, and then with ball mill etc. with particle size distribution D ₅₀Be 0.5 ± 0.2 μ m, D ₉₀This calcining matter of mode case of wet attrition for less than 0.8 μ m.The powders calcined of the piezoelectric ceramic of the PZT that mix to pulverize etc., the adhesive that constitutes with organic polymer, and the plasticizer of DBP (dibutyl phthalate), DOP (dioctyl phthalate) etc. by propylene system, butyral system etc., make slurry, utilize the well-known band methods of forming such as the skill in using a kitchen knife in cookery or stack method of scraping this slurry to be made as the ceramic green sheet that constitutes piezoelectrics 1.

Then, in Ag-Pd or Pt powder, add mixed adhesive, plasticizer etc., make conductive paste, and this conductive paste is printed the thickness of 1～40 μ m by screen printing etc. on the upper surface of described each raw cook.

Then, lamination is printed with the raw cook of conductive paste on upper surface, and after under the temperature of regulation, this laminate being carried out the unsticking mixture, by making column laminate 1a at 900～1200 ℃ of following sintering.

In addition, column laminate 1a is not limited to by the said method manufacturing, if can make the column laminate 1a that alternately lamination multi-disc piezoelectrics and multi-disc internal electrode form, then forms by arbitrary method and all can.

Utilize cutter sweep etc. every one deck in the side of column laminate 1a form groove thereafter.

At 550～700 ℃ following sintering silver glass conductive pastes etc., just can form outer electrode 4 thereafter.

Then, the column laminate 1a that will be formed with outer electrode 4 impregnated in the silicone rubber solution, and silicone rubber solution is carried out vacuum degassing, with the inner filled silicon rubber of this groove at column laminate 1a, from silicone rubber solution pull out column laminate 1a, silicon rubber is coated on the side of column laminate 1a thereafter.The described silicon rubber side that be filled in groove inside and be coated on column laminate 1a on solidified thereafter.

Thereafter, by lead 6 is connected on the outer electrode 4, multi-layer piezoelectric element of the present invention has just been finished.

And, utilize 5 pairs of pair of external electrodes 4 of lead to apply the direct voltage of 0.1～3kV/mm, to the column laminate 1a processing that polarizes, just finished with this stack-up type piezo-activator as goods, if lead 5 is connected on the outside voltage supply unit, utilize lead 5 and outer electrode 4 to come internal electrode 2 is applied voltage, then each piezoelectrics 1 utilizes reciprocal piezoelectric effect to come displacement significantly, just for example is supplied in the automotive fuel injection valve of engine and brings into play its function as fuel is sprayed with this.

In above execution mode one to ten, be preferably, internal electrode 2 has the space, is 5～70% with respect to the area whole sectional area, that the space is occupied in the cross section of internal electrode 2 than (below, be called voidage).

Like this, the internal electrode 2 that includes the space by use constitutes the stack-up type piezoelectric element, just can access the high multi-layer piezoelectric element of durability.If the voidage in the internal electrode 2 is littler than 5%, then with respect to the restraining force grow of the displacement of piezoelectrics, thereby the effect that produces because of the existence of voidage diminishes.Again, if the voidage in the internal electrode 2 is bigger than 70%, then the conductivity of internal electrode 2 diminishes and the intensity reduction, so be not preferred.In order to improve the durability of element, the voidage that is preferably internal electrode 2 is 7～70%, and more preferably the voidage of internal electrode 2 is 10～60%, just can guarantee high addendum modification and obtain high-durability with this.

At this, as above-mentioned, the voidage of internal electrode 2 is meant the whole sectional area with respect to the cross section of internal electrode 2, the area ratio that the space is occupied, and can followingly try to achieve particularly.

That is, cut off multi-layer piezoelectric element abreast with the lamination direction, for example, the space occupied area that whole sectional area in the internal electrode 2 that utilizes microscopic examination to obtain to expose on its longitudinal section and space are occupied.And, recently calculate the voidage ((space occupied area/whole sectional area) * 100) of internal electrode 2 from its area.

Again, the internal electrode 2 that includes the space can followingly be made.

At first, as the metal dust that constitutes internal electrode 2, can in internal electrode 2, interstitial mode use the different material more than 2 kinds of fusing point behind the sintering.At this moment, as required, also can use alloy as metal material.

And, more than the fusing point of the metal that fusing point is minimum in constituting the metal dust of internal electrode 2 and the temperature roasting below the fusing point of the highest metal of fusing point.If at such roasting temperature, then constitute in the metal dust of internal electrode 2 because of its more than fusing point melt metal or alloy just move in the gap of melt metal not by capillarity, thereby in formation space, the residing place of melt metal.In the method, can the voidage of internal electrode 2 be set at the ratio of hope by adjusting the blending ratio and the temperature of the metal dust more than two kinds that constitutes internal electrode 2.

In addition, the space of internal electrode 2 for example utilizes the minim gap that forms when the conductive paste that uses in order to form internal electrode 2 adjusting between metal dust, perhaps be contained in adhesive in the conductive paste and burn gap that the back produces and wait to form and also can.

Again, also can be by making an addition to the material of the material wetting quality difference that constitutes internal electrode 2 in the conductive paste that internal electrode uses, perhaps be printed with internal electrode with the surface of the piezoelectrics raw cook of conductive paste on the material of coating and the material wetting quality difference that constitutes internal electrode 2, in internal electrode 2, form the space.At this, as with the material of the material wetting quality difference that constitutes internal electrode 2, for example can exemplify BN.

In above execution mode one to ten, the multi-layer piezoelectric element of specific structure has been described respectively, but in the present invention, that can make up above explanation to usually constitute all multi-layer piezoelectric elements allly.For example, on the element of the structure shown in Fig. 4 A, 4B, be combined in the execution mode one to nine piezoelectric body layer of explanation and inside or outer electrode also can, the piezoelectrics pottery that is applied in explanation in the execution mode ten on the element of the structure shown in Figure 1A also can.

Execution mode 11

Fig. 3 is the figure of injection apparatus of expression embodiments of the present invention 11, is provided with spray-hole 33 at an end of accommodating container 31, contains the needle valve 35 that can open and close spray-hole 33 again in accommodating container 31.

Can be communicated with spray-hole 33 ground and be provided with fuel passage 37, this fuel passage 37 is linked on the outside fuel supply source, and fuel is supplying in the fuel passage 37 under the constant high pressure always.Thereby be formed as follows: if needle valve 35 open spray-holes 33, the fuel that then supplies in the fuel passage 37 is ejected under certain high pressure in the not shown fuel chambers of internal combustion engine.

Again, the upper end of needle valve 35, it is big that its diameter becomes, and becomes the piston 41 that can slide with the cylinder 39 that is formed in the accepting container 31.And, in accommodating container 31, taken in above-mentioned piezo-activator 43.

In such injection apparatus, if piezo-activator 43 is applied in voltage and extends, then piston 41 is pressed, needle valve 35 inaccessible spray-holes 33, thus the supply of fuel stops.Again, if voltage application stops, then piezo-activator 43 shrinks, disk spring 45 back-pressure pistons 41, and spray-hole 33 is communicated with fuel passage 37, thereby carries out the injection of fuel.

Again, the present invention relates to multi-layer piezoelectric element and injection apparatus, but be not limited to the foregoing description, for example, even be not the fuel injection device that carries at motor car engine, liquid injection apparatus such as ink-jet, driving element in precision positioning device such as Optical devices or the anti-locking apparatus of vibration etc., perhaps carry at combustion pressure sensor, knock transducer, acceleration transducer, load transducer, ultrasonic sensor, voltage sensitive sensor, sensor element in the yaw rate sensor etc., and carry at piezoelectric gyroscope, Piezoelectric switches, piezoelectric transformer, circuit element in the piezoelectricity breaker etc., but so long as used the element of piezoelectric property, certainly also can implement, this point is self-evident.

Embodiment

(embodiment one)

The following manufacturing of stack-up type piezo-activator that constitutes by multi-layer piezoelectric element of the present invention.

At first, mix with lead zirconate titanate (PbZrO ₃-PbTiO ₃) make slurry for powders calcined, adhesive and the plasticizer of the piezoelectric ceramic of principal component, make the ceramic green sheet of the formation piezoelectrics 11 of thickness 150 μ m with the scraper legal system.

300 of laminations are formed on the plate that the single face of this ceramic green sheet on obtain with the thickness of 3 μ m with add the conductive paste that adhesive forms in the silver-palladium alloy that ratio of components forms arbitrarily by utilizing screen printing, at 1000 ℃ of following sintering.In addition, in the raw material of piezoelectrics 11, internal electrode 12 and outer electrode 15, add K ₂CO ₃Perhaps Na ₂CO ₃Powder.

The alkali metal that is contained in multi-layer piezoelectric element, piezoelectrics, internal electrode and the outer electrode of the sintered body that obtains uses icp analysis to detect.

Utilize cutter sweep in the end of the internal electrode of the side of laminate every one deck ground form the groove of the degree of depth 50 μ ms, width 50 μ ms thereafter.

Then, laminar silver powder 90% volume of average grain diameter 2 μ m, with average grain diameter 2 μ m, that with silicon be principal component, softening point be in 640 ℃ the mixture of amorphous glass powder 10% volume, the adhesive that adds 8 mass parts with respect to silver powder with total weight 100 mass parts of glass powder also mixes fully, thereby makes silver-colored glass conductive paste.The silver-colored glass conductivity glass paste that utilizes screen printing to make like this is formed on the mould release film, after the drying, peels off from mould release film, thereby obtains the plate of silver-colored glass conductive paste.The green density of measuring this plate with Archimedes's method is 6.5g/cm as can be known ³

Then, the plate of silver-colored glass paste is transferred on the external electric pole-face of laminate, under 650 ℃, carries out 30 minutes sintering, thereby form the outer electrode that constitutes by the porous matter electric conductor that constitutes the three-dimensional network structure.In addition, the voidage of the outer electrode of this moment utilizes the image analysis apparatus of the cross-section photograph of outer electrode to measure, and is 40% as can be known.

, lead be connected in outer electrode on, utilize lead that the outer electrode of positive pole and negative pole is applied the DC electric field of 15 minutes 3kV/mm thereafter, the processing that polarizes, thus make the stack-up type piezo-activator that has used multi-layer piezoelectric element as shown in Figure 1.

The multi-layer piezoelectric element that obtains is applied the direct voltage of 170V, consequently, on the lamination direction, obtain the addendum modification of 45 μ m.And then, at room temperature with the frequency of 150Hz to this multi-layer piezoelectric element apply 0～+ alternating voltage of 170V, drive test.

Then, measure this multi-layer piezoelectric element and reach driving number of times 1 * 10 ⁹Addendum modification when inferior (μ m), with the addendum modification of the multi-layer piezoelectric element initial condition of beginning before the Continuous Drive relatively, the degradation of addendum modification and multi-layer piezoelectric element is calculated as the rate of change (%) of addendum modification, shown in table 1～4.In addition, table 1 is the table that the alkali metal in the multi-layer piezoelectric element is changed, and table 2 is tables that the alkali metal in the piezoelectrics is changed, and table 3 is tables that the alkali metal in the internal electrode is changed, and table 4 is tables that the alkali metal in the outer electrode is changed.

Table 1

Table 1-1

No	Alkali metal amount (ppm) in the piezoelectrics	Alkali-metal kind	The addendum modification of initial condition (μ m)=A
No	Alkali metal amount (ppm) in the piezoelectrics	Alkali-metal kind	The addendum modification of initial condition (μ m)=A	^*1-1	2	Na	Sintering piezoelectrics not
1-2	5	Na	45.0	^*1-1	2	Na	Sintering piezoelectrics not
1-2	5	Na	45.0	1-3	30	Na	45.0
1-4	50	Na	45.0	1-3	30	Na	45.0
1-4	50	Na	45.0	1-5	70	Na	45.0
1-6	100	Na	45.0	1-5	70	Na	45.0
1-6	100	Na	45.0	1-7	250	Na	45.0
1-8	500	Na	45.0	1-7	250	Na	45.0
1-8	500	Na	45.0	^*1-9	750	Na	45.0
1-10	5	K	45.0	^*1-9	750	Na	45.0
1-10	5	K	45.0	1-11	30	K	45.0
1-12	50	K	45.0	1-11	30	K	45.0
1-12	50	K	45.0	1-13	70	K	45.0
1-14	100	K	45.0	1-13	70	K	45.0
1-14	100	K	45.0	1-15	250	K	45.0
1-16	500	K	45.0	1-15	250	K	45.0
1-16	500	K	45.0	^*1-17	750	K	45.0

Table 1-2

No	Continuous Drive (1 * 10 ⁹) addendum modification (μ m)=B after inferior	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*1-1	-	-
1-2	45.0	0.0	^*1-1	-	-
1-2	45.0	0.0	1-3	44.9	0.2
1-4	44.8	0.4	1-3	44.9	0.2
1-4	44.8	0.4	1-5	44.6	0.9
1-6	44.6	0.9	1-5	44.6	0.9
1-6	44.6	0.9	1-7	44.5	1.1
1-8	44.4	1.3	1-7	44.5	1.1
1-8	44.4	1.3	^*1-9	44.0	2.2
1-10	45.0	0.0	^*1-9	44.0	2.2
1-10	45.0	0.0	1-11	44.9	0.2
1-12	44.8	0.4	1-11	44.9	0.2
1-12	44.8	0.4	1-13	44.6	0.9
1-14	44.6	0.9	1-13	44.6	0.9
1-14	44.6	0.9	1-15	44.5	1.1
1-16	44.4	1.3	1-15	44.5	1.1
1-16	44.4	1.3	^*1-17	44.0	2.2

^*Outside the scope of invention

Table 2

Table 2-1

No	Alkali metal amount (ppm) in the internal electrode	Alkali-metal kind	The addendum modification of initial condition (μ m)=A
No	Alkali metal amount (ppm) in the internal electrode	Alkali-metal kind	The addendum modification of initial condition (μ m)=A	^*1-18	2	Na	Sintering piezoelectrics not
1-19	5	Na	45.0	^*1-18	2	Na	Sintering piezoelectrics not
1-19	5	Na	45.0	1-20	30	Na	45.0
1-21	50	Na	45.0	1-20	30	Na	45.0
1-21	50	Na	45.0	1-22	70	Na	45.0
1-23	100	Na	45.0	1-22	70	Na	45.0
1-23	100	Na	45.0	1-24	250	Na	45.0
1-25	500	Na	45.0	1-24	250	Na	45.0
1-25	500	Na	45.0	^*1-26	750	Na	45.0
1-27	5	K	45.0	^*1-26	750	Na	45.0
1-27	5	K	45.0	1-28	30	K	45.0
1-29	50	K	45.0	1-28	30	K	45.0
1-29	50	K	45.0	1-30	70	K	45.0
1-31	100	K	45.0	1-30	70	K	45.0
1-31	100	K	45.0	1-32	250	K	45.0
1-33	500	K	45.0	1-32	250	K	45.0
1-33	500	K	45.0	^**1-34	750	K	45.0

Table 2-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*1-18	-	-
1-19	45.0	0.0	^*1-18	-	-
1-19	45.0	0.0	1-20	44.9	0.2
1-21	44.8	0.4	1-20	44.9	0.2
1-21	44.8	0.4	1-22	44.6	0.9
1-23	44.6	0.9	1-22	44.6	0.9
1-23	44.6	0.9	1-24	44.5	1.1
1-25	44.4	1.3	1-24	44.5	1.1
1-25	44.4	1.3	^*1-26	44.0	2.2
1-27	45.0	0.0	^*1-26	44.0	2.2
1-27	45.0	0.0	1-28	44.9	0.2
1-29	44.8	0.4	1-28	44.9	0.2
1-29	44.8	0.4	1-30	44.6	0.9
1-31	44.6	0.9	1-30	44.6	0.9
1-31	44.6	0.9	1-32	44.5	1.1
1-33	44.4	1.3	1-32	44.5	1.1
1-33	44.4	1.3	^*1-34	44.0	2.2

Table 3

Table 3-1

No	Alkali metal amount (ppm) in the outer electrode	Alkali-metal kind	The addendum modification of initial condition (μ m)=A
No	Alkali metal amount (ppm) in the outer electrode	Alkali-metal kind	The addendum modification of initial condition (μ m)=A	^*1-35	2	Na	Sintering piezoelectrics not
1-36	5	Na	45.0	^*1-35	2	Na	Sintering piezoelectrics not
1-36	5	Na	45.0	1-37	30	Na	45.0
1-38	50	Na	45.0	1-37	30	Na	45.0
1-38	50	Na	45.0	1-39	70	Na	45.0
1-40	100	Na	45.0	1-39	70	Na	45.0
1-40	100	Na	45.0	1-41	250	Na	45.0
1-42	500	Na	45.0	1-41	250	Na	45.0
1-42	500	Na	45.0	^*1-43	750	Na	45.0
1-44	5	K	45.0	^*1-43	750	Na	45.0
1-44	5	K	45.0	1-45	30	K	45.0
1-46	50	K	45.0	1-45	30	K	45.0
1-46	50	K	45.0	1-47	70	K	45.0
1-48	100	K	45.0	1-47	70	K	45.0
1-48	100	K	45.0	1-49	250	K	45.0
1-50	500	K	45.0	1-49	250	K	45.0
1-50	500	K	45.0	^*1-51	750	K	45.0

Table 3-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*1-35	-	-
1-36	45.0	0.0	^*1-35	-	-
1-36	45.0	0.0	1-37	44.9	0.2
1-38	44.8	0.4	1-37	44.9	0.2
1-38	44.8	0.4	1-39	44.6	0.9
1-40	44.6	0.9	1-39	44.6	0.9
1-40	44.6	0.9	1-41	44.5	1.1
1-42	44.4	1.3	1-41	44.5	1.1
1-42	44.4	1.3	^*1-43	44.0	2.2
1-44	45.0	0.0	^*1-43	44.0	2.2
1-44	45.0	0.0	1-45	44.9	0.2
1-46	44.8	0.4	1-45	44.9	0.2
1-46	44.8	0.4	1-47	44.6	0.9
1-48	44.6	0.9	1-47	44.6	0.9
1-48	44.6	0.9	1-49	44.5	1.1
1-50	44.4	1.3	1-49	44.5	1.1
1-50	44.4	1.3	^*1-51	44.0	2.2

Table 4

Table 4-1

No	Alkali metal amount (ppm) in the element	Alkali-metal kind	The addendum modification of initial condition (μ m)=A
No	Alkali metal amount (ppm) in the element	Alkali-metal kind	The addendum modification of initial condition (μ m)=A	^*1-52	2	Na	Sintering piezoelectrics not
1-53	5	Na	45.0	^*1-52	2	Na	Sintering piezoelectrics not
1-53	5	Na	45.0	1-54	30	Na	45.0
1-55	50	Na	45.0	1-54	30	Na	45.0
1-55	50	Na	45.0	1-56	70	Na	45.0
1-57	100	Na	45.0	1-56	70	Na	45.0
1-57	100	Na	45.0	1-58	250	Na	45.0
1-59	500	Na	45.0	1-58	250	Na	45.0
1-59	500	Na	45.0	^*1-60	750	Na	45.0
1-61	5	K	45.0	^*1-60	750	Na	45.0
1-61	5	K	45.0	1-62	30	K	45.0
1-63	50	K	45.0	1-62	30	K	45.0
1-63	50	K	45.0	1-64	70	K	45.0
1-65	100	K	45.0	1-64	70	K	45.0
1-65	100	K	45.0	1-66	250	K	45.0
1-67	500	K	45.0	1-66	250	K	45.0
1-67	500	K	45.0	^*1-68	750	K	45.0

Table 4-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*1-52	-	-
1-53	45.0	0.0	^*1-52	-	-
1-53	45.0	0.0	1-54	44.9	0.2
1-55	44.8	0.4	1-54	44.9	0.2
1-55	44.8	0.4	1-56	44.6	0.9
1-57	44.6	0.9	1-56	44.6	0.9
1-57	44.6	0.9	1-58	44.5	1.1
1-59	44.4	1.3	1-58	44.5	1.1
1-59	44.4	1.3	^*1-60	44.0	2.2
1-61	45.0	0.0	^*1-60	44.0	2.2
1-61	45.0	0.0	1-62	44.9	0.2
1-63	44.8	0.4	1-62	44.9	0.2
1-63	44.8	0.4	1-64	44.6	0.9
1-65	44.6	0.9	1-64	44.6	0.9
1-65	44.6	0.9	1-66	44.5	1.1
1-67	44.4	1.3	1-66	44.5	1.1
1-67	44.4	1.3	^*1-68	44.0	2.2

^*Outside the scope of invention

From as can be known with table, surpass 300ppm as if the alkali metal in the multi-layer piezoelectric element, then rate of change (%) uprises sharp, thus deterioration increases.If lower, then can not carry out the sintering of piezoelectrics, thereby not have function as piezoelectrics than 5ppm again.Thereby by making alkali metal in the multi-layer piezoelectric element below the above 300ppm of 5ppm, even long-term the driving, in fact the addendum modification of hope does not change yet, thus install not misoperation, thus the piezo-activator of the high reliability of good endurance can be provided.

With regard to the alkali-metal amount in being contained in piezoelectrics, internal electrode, outer electrode, also be same.

(embodiment two)

In piezoelectrics, add titanium chloride, in the raw material of internal electrode, outer electrode, add AgCl, in addition, carry out identical experiment with embodiment one.In addition, the halogens that is contained in piezoelectrics, internal electrode and the outer electrode of the multi-layer piezoelectric element that obtains uses ion chromatography to detect.Experimental result is shown in table 5～8.

Table 5

Table 5-1

No	Halogens amount (ppm) in the piezoelectrics	The kind of halogens	The addendum modification of initial condition (μ m)=A
No	Halogens amount (ppm) in the piezoelectrics	The kind of halogens	The addendum modification of initial condition (μ m)=A	^*2-1	2	Cl	Sintering piezoelectrics not
2-2	5	Cl	45.0	^*2-1	2	Cl	Sintering piezoelectrics not
2-2	5	Cl	45.0	2-3	20	Cl	45.0
2-4	50	Cl	45.0	2-3	20	Cl	45.0
2-4	50	Cl	45.0	2-5	70	Cl	45.0
2-6	100	Cl	45.0	2-5	70	Cl	45.0
2-6	100	Cl	45.0	2-7	500	Cl	45.0
2-8	1500	Cl	45.0	2-7	500	Cl	45.0
2-8	1500	Cl	45.0	^*2-9	2000	Cl	45.0
2-10	5	Br	45.0	^*2-9	2000	Cl	45.0
2-10	5	Br	45.0	2-11	20	Br	45.0
2-12	50	Br	45.0	2-11	20	Br	45.0
2-12	50	Br	45.0	2-13	70	Br	45.0
2-14	100	Br	45.0	2-13	70	Br	45.0
2-14	100	Br	45.0	2-15	500	Br	45.0
2-16	1500	Br	45.0	2-15	500	Br	45.0
2-16	1500	Br	45.0	^*2-17	2000	Br	45.0

Table 5-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*2-1	-	-
2-2	45.0	0.0	^*2-1	-	-
2-2	45.0	0.0	2-3	44.9	0.2
2-4	44.8	0.4	2-3	44.9	0.2
2-4	44.8	0.4	2-5	44.6	0.9
2-6	44.6	0.9	2-5	44.6	0.9
2-6	44.6	0.9	2-7	44.5	1.1
2-8	44.4	1.3	2-7	44.5	1.1
2-8	44.4	1.3	^*2-9	44.0	2.2
2-10	45.0	0.0	^*2-9	44.0	2.2
2-10	45.0	0.0	2-11	44.9	0.2
2-12	44.8	0.4	2-11	44.9	0.2
2-12	44.8	0.4	2-13	44.6	0.9
2-14	44.6	0.9	2-13	44.6	0.9
2-14	44.6	0.9	2-15	44.5	1.1
2-16	44.4	1.3	2-15	44.5	1.1
2-16	44.4	1.3	^*2-17	44.0	2.2

^*Outside the scope of invention

Table 6

Table 6-1

No	Halogens amount (ppm) in the internal electrode	The kind of halogens	The addendum modification of initial condition (μ m)=A
No	Halogens amount (ppm) in the internal electrode	The kind of halogens	The addendum modification of initial condition (μ m)=A	^*2-18	2	Cl	Sintering piezoelectrics not
2-19	5	Cl	45.0	^*2-18	2	Cl	Sintering piezoelectrics not
2-19	5	Cl	45.0	2-20	20	Cl	45.0
2-21	50	Cl	45.0	2-20	20	Cl	45.0
2-21	50	Cl	45.0	2-22	70	Cl	45.0
2-23	100	Cl	45.0	2-22	70	Cl	45.0
2-23	100	Cl	45.0	2-24	500	Cl	45.0
2-25	1500	Cl	45.0	2-24	500	Cl	45.0
2-25	1500	Cl	45.0	^*2-26	2000	Cl	45.0
2-27	5	Br	45.0	^*2-26	2000	Cl	45.0
2-27	5	Br	45.0	2-28	20	Br	45.0
2-29	50	Br	45.0	2-28	20	Br	45.0
2-29	50	Br	45.0	2-30	70	Br	45.0
2-31	100	Br	45.0	2-30	70	Br	45.0
2-31	100	Br	45.0	2-32	500	Br	45.0
2-33	1500	Br	45.0	2-32	500	Br	45.0
2-33	1500	Br	45.0	^*2-34	2000	Br	45.0

^*Outside the scope of invention

Table 6-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*2-18	-	-
2-19	45.0	0.0	^*2-18	-	-
2-19	45.0	0.0	2-20	44.9	0.2
2-21	44.8	0.4	2-20	44.9	0.2
2-21	44.8	0.4	2-22	44.6	0.9
2-23	44.6	0.9	2-22	44.6	0.9
2-23	44.6	0.9	2-24	44.5	1.1
2-25	44.4	1.3	2-24	44.5	1.1
2-25	44.4	1.3	^*2-26	44.0	2.2
2-27	45.0	0.0	^*2-26	44.0	2.2
2-27	45.0	0.0	2-28	44.9	0.2
2-29	44.8	0.4	2-28	44.9	0.2
2-29	44.8	0.4	2-30	44.6	0.9
2-31	44.6	0.9	2-30	44.6	0.9
2-31	44.6	0.9	2-32	44.5	1.1
2-33	44.4	1.3	2-32	44.5	1.1
2-33	44.4	1.3	^*2-34	44.0	2.2

Table 7

Table 7-1

No	Halogens amount (ppm) in the outer electrode	The kind of halogens	The addendum modification of initial condition (μ m)=A
No	Halogens amount (ppm) in the outer electrode	The kind of halogens	The addendum modification of initial condition (μ m)=A	^*2-35	2	Cl	Sintering piezoelectrics not
2-36	5	Cl	45.0	^*2-35	2	Cl	Sintering piezoelectrics not
2-36	5	Cl	45.0	2-37	20	Cl	45.0
2-38	50	Cl	45.0	2-37	20	Cl	45.0
2-38	50	Cl	45.0	2-39	70	Cl	45.0
2-40	100	Cl	45.0	2-39	70	Cl	45.0
2-40	100	Cl	45.0	2-41	500	Cl	45.0
2-42	1500	Cl	45.0	2-41	500	Cl	45.0
2-42	1500	Cl	45.0	^*2-43	2000	Cl	45.0
2-44	5	Br	45.0	^*2-43	2000	Cl	45.0
2-44	5	Br	45.0	2-45	20	Br	45.0
2-46	50	Br	45.0	2-45	20	Br	45.0
2-46	50	Br	45.0	2-47	70	Br	45.0
2-48	100	Br	45.0	2-47	70	Br	45.0
2-48	100	Br	45.0	2-49	500	Br	45.0
2-50	1500	Br	45.0	2-49	500	Br	45.0
2-50	1500	Br	45.0	^*2-51	2000	Br	45.0

Table 7-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*2-35	-	-
2-36	45.0	0.0	^*2-35	-	-
2-36	45.0	0.0	2-37	44.9	0.2
2-38	44.8	0.4	2-37	44.9	0.2
2-38	44.8	0.4	2-39	44.6	0.9
2-40	44.6	0.9	2-39	44.6	0.9
2-40	44.6	0.9	2-41	44.5	1.1
2-42	44.4	1.3	2-41	44.5	1.1
2-42	44.4	1.3	^*2-43	44.0	2.2
2-44	45.0	0.0	^*2-43	44.0	2.2
2-44	45.0	0.0	2-45	44.9	0.2
2-46	44.8	0.4	2-45	44.9	0.2
2-46	44.8	0.4	2-47	44.6	0.9
2-48	44.6	0.9	2-47	44.6	0.9
2-48	44.6	0.9	2-49	44.5	1.1
2-50	44.4	1.3	2-49	44.5	1.1
2-50	44.4	1.3	^*2-51	44.0	2.2

Table 8

Table 8-1

No	Halogens amount (ppm) in the element	The kind of halogens	The addendum modification of initial condition (μ m)=A
No	Halogens amount (ppm) in the element	The kind of halogens	The addendum modification of initial condition (μ m)=A	^*2-52	2	Cl	Sintering piezoelectrics not
2-53	5	Cl	45.0	^*2-52	2	Cl	Sintering piezoelectrics not
2-53	5	Cl	45.0	2-54	20	Cl	45.0
2-55	50	Cl	45.0	2-54	20	Cl	45.0
2-55	50	Cl	45.0	2-56	70	Cl	45.0
2-57	100	Cl	45.0	2-56	70	Cl	45.0
2-57	100	Cl	45.0	2-58	500	Cl	45.0
2-59	1000	Cl	45.0	2-58	500	Cl	45.0
2-59	1000	Cl	45.0	^*2-60	1500	Cl	45.0
2-61	5	Br	45.0	^*2-60	1500	Cl	45.0
2-61	5	Br	45.0	2-62	20	Br	45.0
2-63	50	Br	45.0	2-62	20	Br	45.0
2-63	50	Br	45.0	2-64	70	Br	45.0
2-65	100	Br	45.0	2-64	70	Br	45.0
2-65	100	Br	45.0	2-66	500	Br	45.0
2-67	1000	Br	45.0	2-66	500	Br	45.0
2-67	1000	Br	45.0	^*2-68	1500	Br	45.0

Table 8-2

No	Continuous Drive (1 * 10 ⁹) after addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/A * 100\|
No			^*2-52	-	-
2-53	45.0	0.0	^*2-52	-	-
2-53	45.0	0.0	2-54	44.9	0.2
2-55	44.8	0.4	2-54	44.9	0.2
2-55	44.8	0.4	2-56	44.6	0.9
2-57	44.6	0.9	2-56	44.6	0.9
2-57	44.6	0.9	2-58	44.5	1.1
2-59	44.4	1.3	2-58	44.5	1.1
2-59	44.4	1.3	^*2-60	44.0	2.2
2-61	45.0	0.0	^*2-60	44.0	2.2
2-61	45.0	0.0	2-62	44.9	0.2
2-63	44.8	0.4	2-62	44.9	0.2
2-63	44.8	0.4	2-64	44.6	0.9
2-65	44.6	0.9	2-64	44.6	0.9
2-65	44.6	0.9	2-66	44.5	1.1
2-67	44.4	1.3	2-66	44.5	1.1
2-67	44.4	1.3	^*2-68	44.0	2.2

From as can be known with table, surpass 1000ppm as if the halogens in the multi-layer piezoelectric element, then rate of change (%) uprises sharp, thus the deterioration aggravation.If lower, then can not carry out the sintering of piezoelectrics, thereby not have function as piezoelectrics than 5ppm again.Thereby, by making halogens in the multi-layer piezoelectric element below the above 300ppm of 5ppm, even long-term the driving, in fact the addendum modification of hope does not change yet, so install not misoperation, thereby the piezo-activator of the high reliability of good endurance can be provided.

With regard to the amount of the halogens in being contained in piezoelectrics, internal electrode, outer electrode, also be same.

(embodiment three)

In embodiment three, use and to form the multi-layer piezoelectric element that constitutes by the material of different internal electrodes, carry out the experiment same with embodiment one.Its result is as shown in table 9.

Table 9

Table 9-1

No	Pd in the internal electrode metal (% weight)	Pt in the internal electrode metal (% weight)	Ag in the internal electrode metal (% weight)	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition
No	Pd in the internal electrode metal (% weight)	Pt in the internal electrode metal (% weight)	Ag in the internal electrode metal (% weight)		3-1	0	0	100	Because of the migration breakage
3-2	0.001	0	99.999	0.7	3-1	0	0	100	Because of the migration breakage
3-2	0.001	0	99.999	0.7	3-3	0.01	0	99.99	0.7
3-4	0.1	0	99.9	0.4	3-3	0.01	0	99.99	0.7
3-4	0.1	0	99.9	0.4	3-5	0.5	0	99.5	0.2
3-6	1	0	99	0.2	3-5	0.5	0	99.5	0.2
3-6	1	0	99	0.2	3-7	2	0	98	0
3-8	4	1	95	0	3-7	2	0	98	0
3-8	4	1	95	0	3-9	5	0	95	0
3-10	8	0	92	0	3-9	5	0	95	0
3-10	8	0	92	0	3-11	9	0	91	0.2
3-12	9.5	0	90.5	0.2	3-11	9	0	91	0.2
3-12	9.5	0	90.5	0.2	3-13	10	0	90	0.4
3-14	15	0	85	0.7	3-13	10	0	90	0.4
3-14	15	0	85	0.7	3-15	20	0	80	0.9
3-16	30	0	70	0.9	3-15	20	0	80	0.9

Table 9-2

No	Other internal electrode metal (% weight)	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition
No	Other internal electrode metal (% weight)		3-17	Cu 100％	0.2
3-18	Cu 99.99％	0.1	3-17	Cu 100％	0.2
3-18	Cu 99.99％	0.1	3-19	Ni 100％	0.4

From with table as can be known, making under internal electrode 12 situation for silver 100% of No.3-1, multi-layer piezoelectric element is damaged because of the silver migration, thereby can not Continuous Drive.Again, in No.3-15, the 3-16 metal constituent in internal electrode 12, because the amount of VIII family metal surpasses 15% weight, again, the amount less than 85% of Ib family metal, thus deterioration increase because of Continuous Drive, so the durability of stack-up type piezo-activator reduces.

With respect to this, metal constituent in No.3-2～No.3-14 internal electrode is that the amount of M1% quality, Ib family metal is when being the M2% quality with the amount at VIII family metal, the metal constituent that satisfies 0≤M1≤15,85≤M2≤100, M1+M2=100% quality is a principal component, so can make the ratio resistance of internal electrode little, even Continuous Drive also can be suppressed at the heating that produces in the internal electrode, so can make the stable stack-up type piezo-activator of element addendum modification.

In addition, the present invention is not limited to the foregoing description, and it is also harmless to carry out all changes in the scope that does not break away from purport of the present invention.

Embodiment four to six

In embodiments of the invention four to six, the following making of stack-up type piezo-activator that constitutes by multi-layer piezoelectric element.

300 of laminations are formed on the plate that the single face of this ceramic green sheet on obtain with the thickness of 3 μ m with add the conductive paste that adhesive forms in the silver-palladium alloy that ratio of components forms arbitrarily by utilizing screen printing, at 1000 ℃ of following sintering.

Then, utilize cutter sweep to form the groove of the degree of depth 50 μ m, width 50 μ m every one deck ground in the end of the internal electrode of the side of laminate.

Then, laminar silver powder 90% volume of average grain diameter 2 μ m, with remainder be that average grain diameter 2 μ m, that be principal component, softening point is in 640 ℃ the mixture of amorphous glass powder 10% volume with silicon, the adhesive that adds 8 mass parts with respect to silver powder with total weight 100 mass parts of glass powder also mixes fully, thereby makes silver-colored glass conductive paste.The silver-colored glass conductivity glass paste that utilizes screen printing to make like this is formed on the mould release film, after the drying, peels off from mould release film, thereby obtains the plate of silver-colored glass conductive paste.The green density of measuring this plate with Archimedes's method is 6.5g/cm as can be known ³

Then, the plate of described silver-colored glass paste is transferred on 15 of the outer electrodes of laminate 13, under 650 ℃, carries out 30 minutes sintering, thereby form the outer electrode 15 that constitutes by the porous matter electric conductor that constitutes the three-dimensional network structure.In addition, the voidage of outer electrode 15 of this moment, utilizing the image analysis apparatus of the cross-section photograph of outer electrode 15 to measure is 40% as can be known.

Thereafter, lead is connected on the outer electrode 15, utilize lead that the outer electrode 15 of positive pole and negative pole is applied the DC electric field of 15 minutes 3kV/mm, the processing that polarizes, thus make the stack-up type piezo-activator that has used multi-layer piezoelectric element as shown in Figure 1.

(embodiment four)

Except above-mentioned method for making, in the resistance value of control element resistance or the dielectric loss of piezoelectrics 11 (tan δ) and in the stack-up type piezo-activator of making of the present invention, measure the component size before and after the Continuous Drive of stack-up type piezo-activator and the rate of change of component temperature, verify they with the Continuous Drive of stack-up type piezo-activator after the element addendum modification between related.

Again, as a comparative example, the rate of change that is produced on the component size before and after the Continuous Drive of above-mentioned stack-up type piezo-activator surpasses the sample that forms in 1% the scope.

With respect to the direct voltage that applies 170V as the above-mentioned stack-up type piezo-activator that obtains as can be known, in all stack-up type piezo-activators, on the lamination direction, can both obtain the addendum modification of 45 μ m.And then, at room temperature this stack-up type piezo-activator is applied the alternating voltage of 0～170V with the frequency of 150Hz, carry out Continuous Drive 1 * 10 ⁹Inferior test.The result is as shown in table 10.

Table 10

Table 10-1

No.	With silver 100% resistance as 1 and standardized internal electrode resistance	The addendum modification of initial condition (μ m)=A
No.		The addendum modification of initial condition (μ m)=A	4-1	2	45.0
4-2	3	45.0	4-1	2	45.0
4-2	3	45.0	4-3	4	45.0
4-4	5	45.0	4-3	4	45.0
4-4	5	45.0	4-5	8	45.0
4-6	10	45.0	4-5	8	45.0
4-6	10	45.0	4-7	5	45.0
^*4-8	10	45.0	4-7	5	45.0

Table 10-2

No.	Continuous Drive front and back (1 * 10 ⁹Inferior) component temperature rate of change (%)	Continuous Drive front and back (1 * 10 ⁹Inferior) component size rate of change (%)	Continuous Drive front and back (1 * 10 ⁹Inferior) element addendum modification (μ m)=B
No.				4-1	0.0	0.0	45.0
4-2	0.5	0.1	44.9	4-1	0.0	0.0	45.0
4-2	0.5	0.1	44.9	4-3	0.9	0.2	44.8
4-4	1.4	0.3	44.7	4-3	0.9	0.2	44.8
4-4	1.4	0.3	44.7	4-5	2.3	0.5	44.5
4-6	3.2	0.7	44.1	4-5	2.3	0.5	44.5
4-6	3.2	0.7	44.1	4-7	4.5	1.0	43.5
^*4-8	9.0	2.0	Because of thermal runaway is destroyed	4-7	4.5	1.0	43.5

As known from Table 10, because being the rate of change of the component size before and after the sample number 4-8 Continuous Drive, comparative example surpasses 1%, so the element addendum modification after the Continuous Drive significantly reduces, and then, because on the junction surface of internal electrode 12 and outer electrode 15, produce the amount of localized heat of high temperature, so the stack-up type piezo-activator causes thermal runaway and destroys.

With respect to this, be among sample number 4-1～4-7 at embodiments of the invention because be before and after the Continuous Drive the rate of change of component size be the 1% stack-up type piezo-activator that forms in interior scope, so even Continuous Drive 1 * 10 ⁹Inferior, the element addendum modification after the Continuous Drive reduces also and indistinctively, has as the stack-up type piezo-activator and the addendum modification of necessary reality does not produce multi-layer piezoelectric element thermal runaway or misoperation, that have good durability thereby can make.

(embodiment five)

Except above-mentioned method for making, in the resistance value of control element resistance or the dielectric loss of piezoelectrics 11 (tan δ) and in the stack-up type piezo-activator of making of the present invention, measure the rate of change and the rate of change of component temperature of the gauge of the internal electrode 12 after the Continuous Drive of stack-up type piezo-activator, verify they with the degradation of representing with the rate of change of the addendum modification of the Continuous Drive front and back of stack-up type piezo-activator between related.

At this, mensuration drives element addendum modification (the element addendum modification after the Continuous Drive) after the stack-up type piezo-activator with number of times arbitrarily, then with the element addendum modification after the described Continuous Drive before with respect to Continuous Drive element addendum modification (addendum modification of initial condition) and the ratio that changes is represented is exactly the degree of degeneration.With this, just can confirm the state of the deterioration that causes because of stipulated number Continuous Drive stack-up type piezo-activator.

Again, as a comparative example, the rate of change that is produced on the gauge of the internal electrode 12 before and after the Continuous Drive of above-mentioned stack-up type piezo-activator surpasses the sample that forms in 5% the scope.

With respect to the direct voltage that applies 170V as the above-mentioned stack-up type piezo-activator that obtains as can be known, in all stack-up type piezo-activators, on the lamination direction, can both obtain the addendum modification of 45 μ m.And then, at room temperature with the frequency of 150Hz to this stack-up type piezo-activator apply 0～+ alternating voltage of 170V, carry out Continuous Drive 1 * 10 ⁹Inferior test.The result is as shown in table 11.

Table 11

Table 11-1

No	With silver 100% resistance as 1 and standardized internal electrode resistance	The dielectric loss tan δ (%) of piezoelectrics	The addendum modification of initial condition (μ m)=A	Continuous Drive front and back (1 * 10 ⁹Inferior) component temperature rate of change (%)
No		The dielectric loss tan δ (%) of piezoelectrics	The addendum modification of initial condition (μ m)=A		5-1	2	0.5	45.0	0.0
5-2	3	0.5	45.0	0.5	5-1	2	0.5	45.0	0.0
5-2	3	0.5	45.0	0.5	5-3	4	0.5	45.0	0.9
5-4	5	0.5	45.0	1.4	5-3	4	0.5	45.0	0.9
5-4	5	0.5	45.0	1.4	5-5	8	0.5	45.0	2.3
5-6	10	0.5	45.0	3.2	5-5	8	0.5	45.0	2.3
5-6	10	0.5	45.0	3.2	5-7	5	1.5	45.0	4.5
^*5-8	8	1.5	45.0	5.4	5-7	5	1.5	45.0	4.5
^*5-8	8	1.5	45.0	5.4	^*5-9	10	2.5	45.0	9.0

Table 11-2

No	Continuous Drive front and back (1 * 10 ⁹Inferior) internal electrode gauge rate of change (%)	Continuous Drive front and back (1 * 10 ⁹Inferior) element addendum modification (μ m)=B	With respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=\| (A-B)/degree (%) of A * 100\|=deterioration
No				5-1	0.0	45.0	0
5-2	0.5	44.9	0.2	5-1	0.0	45.0	0
5-2	0.5	44.9	0.2	5-3	1.0	44.8	0.4
5-4	1.5	44.7	0.7	5-3	1.0	44.8	0.4
5-4	1.5	44.7	0.7	5-5	2.5	44.5	1.1
5-6	3.5	44.1	2.0	5-5	2.5	44.5	1.1
5-6	3.5	44.1	2.0	5-7	5.0	43.5	3.3
^*5-8	6.0	41.4	8.0	5-7	5.0	43.5	3.3
^*5-8	6.0	41.4	8.0	^*5-9	10.0	Because of thermal runaway is destroyed	-

From this table 11 as can be known, surpass 5% because comparative example is the rate of change of the gauge of the internal electrode 12 before and after sample number 5-8 and the 5-9 Continuous Drive, thus the element addendum modification after the Continuous Drive reduce significantly, thereby the degree of deterioration increases.Again, sample number 5-9 oxidation expansion is promoted because of the remarkable heating of internal electrode 12, thereby the stack-up type piezo-activator causes thermal runaway and destroys.

With respect to this, be among sample number 5-1～5-7 at embodiments of the invention because be before and after the Continuous Drive the rate of change of gauge of internal electrode 12 be the 5% stack-up type piezo-activator that forms in interior scope, so even Continuous Drive 1 * 10 ⁹Inferior, the element addendum modification after the Continuous Drive reduces also and indistinctively, has as the stack-up type piezo-activator and the addendum modification of necessary reality does not produce multi-layer piezoelectric element thermal runaway or misoperation, that have good durability thereby can make.

(embodiment six)

In above-mentioned method for making, in having the stack-up type piezo-activator of forming the internal electrode 12 that forms with various electrode materials, measure the maximum rate of change of the element addendum modification in the Continuous Drive of stack-up type piezo-activator, the electrode material of checking internal electrode 12 is formed related between the degree of the deterioration that causes with Continuous Drive because of the stack-up type piezo-activator.

With respect to the direct voltage that applies 170V as the above-mentioned stack-up type piezo-activator that obtains as can be known, in all stack-up type piezo-activators, on the lamination direction, can both obtain the addendum modification of 45 μ m.And then, at room temperature this stack-up type piezo-activator is applied the alternating voltage of 0～170V with the frequency of 150Hz, carry out Continuous Drive 1 * 10 ⁹Inferior test.The result is as shown in table 12.

Table 12

Table 12-1

No	Pd in the internal electrode metal (% weight)	Pt in the internal electrode metal (% weight)	Ag in the internal electrode metal (% weight)
No	Pd in the internal electrode metal (% weight)	Pt in the internal electrode metal (% weight)	Ag in the internal electrode metal (% weight)	6-1	0	0	100
6-2	0.001	0	99.999	6-1	0	0	100
6-2	0.001	0	99.999	6-3	0.01	0	99.99
6-4	0.1	0	99.9	6-3	0.01	0	99.99
6-4	0.1	0	99.9	6-5	0.5	0	99.5
6-6	1	0	99	6-5	0.5	0	99.5
6-6	1	0	99	6-7	2	0	98
6-8	4	1	95	6-7	2	0	98
6-8	4	1	95	6-9	5	0	95
6-10	8	0	92	6-9	5	0	95
6-10	8	0	92	6-11	9	0	91
6-12	9.5	0	90.5	6-11	9	0	91
6-12	9.5	0	90.5	6-13	10	0	90
6-14	15	0	85	6-13	10	0	90
6-14	15	0	85	6-15	0	0	0
6-16	0	0	0	6-15	0	0	0
6-16	0	0	0	6-17	0	0	0
6-18	20	0	80	6-17	0	0	0
6-18	20	0	80	6-19	30	0	70

Table 12-2

No	Cu in the internal electrode metal (% weight)	Ni in the internal electrode metal (% weight)	Degree (%) with respect to the addendum modification rate of change (%) after the Continuous Drive of initial condition=degeneration
No	Cu in the internal electrode metal (% weight)	Ni in the internal electrode metal (% weight)		6-1	0	0	Because of the migration breakage
6-2	0	0	0.70	6-1	0	0	Because of the migration breakage
6-2	0	0	0.70	6-3	0	0	0.70
6-4	0	0	0.40	6-3	0	0	0.70
6-4	0	0	0.40	6-5	0	0	0.20
6-6	0	0	0.20	6-5	0	0	0.20
6-6	0	0	0.20	6-7	0	0	0.00
6-8	0	0	0.00	6-7	0	0	0.00
6-8	0	0	0.00	6-9	0	0	0.00
6-10	0	0	0.00	6-9	0	0	0.00
6-10	0	0	0.00	6-11	0	0	0.20
6-12	0	0	0.20	6-11	0	0	0.20
6-12	0	0	0.20	6-13	0	0	0.40
6-14	0	0	0.70	6-13	0	0	0.40
6-14	0	0	0.70	6-15	99.9	0.1	0.00
6-16	100	0	0.20	6-15	99.9	0.1	0.00
6-16	100	0	0.20	6-17	0	100	0.40
6-18	0	0	1.10	6-17	0	100	0.40
6-18	0	0	1.10	6-19	0	0	1.10

As known from Table 12, because sample number 6-1 forms internal electrode 12 with silver 100%, so cause the silver migration, so the breakage that produces the stack-up type piezo-activator is the Continuous Drive difficulty.

Again, because in the metal constituent in sample number 6-18,6-19 internal electrode 12, the amount of VIII family metal surpasses 15%, again, the amount less than 85% of Ib family metal, thus deterioration increase because of Continuous Drive, so the durability of stack-up type piezo-activator reduces.

With respect to this, the metal constituent of internal electrode 12 is that the amount of M1 (% weight), Ib family metal is when being M2 (% weight) with the amount at VIII family metal among sample number 6-2～6-15, the metal constituent that satisfies 0＜M1≤15,85≤M2＜100, M1+M2=100 is a principal component, so can make the ratio resistance of internal electrode 12 little, even Continuous Drive also can be suppressed in the internal electrode 12 heating that produces, so can make the stable stack-up type actuator of element addendum modification after the Continuous Drive of regulation.

Again, because sample number 6-15～6-17 does to become so that the VIII family metal in the internal electrode 12 is Ni or to make Ib family metal be that the metal group of Cu becomes principal component, so can make the ratio resistance of internal electrode 12 little, even Continuous Drive also can be suppressed in the internal electrode 12 heating that produces, so can make the stable stack-up type actuator of element addendum modification after the Continuous Drive of regulation.

In addition, the present invention is not limited to the foregoing description, and it is also harmless to carry out all changes in the scope that does not break away from the center of the present invention meaning.

Embodiment seven

Sintered body is to become Pb _1-xBa _x(Zn _1/3Nb _2/3) _a(Yb _1/2Nb _1/2) _b(Co _1/3Nb _2/3) _c(Fe _2/3W _1/3) _dNb _e[Zr _0.48Ti _0.52] _1-a-b-c-d-eO ₃The mode weighing ormal weight of (is than 1 little value at this x, a, b, c, d, e), and then the SiO of weighing ormal weight ₂Use includes SiO as impurity in raw material ₂, but the least possible raw material of amount.After with ball mill wet mixed 18 hours, then in this mixture of 900 ℃ of following roastings 2 hours, and then with this calcining matter of case of wet attrition such as ball mill.

Thereafter, mixing organic bond and plasticizer are made slurry in this crushed material, make the raw cook of thickness 150 μ m by the slip-casting method.The conductive paste that is made of the ratio of Ag90% weight, Pd10% weight with the thickness screen printing of 4 μ m on this raw cook, 20 of dry back-set beds (are being measured piezoelectricity distortion constant d ₃₃When be 200 layers) be formed with the raw cook of electrode film, 10 of laminations uncoated on the both ends of the lamination direction of this laminate has the raw cook of conductive paste.

Then, pressurize, make laminate integrated Yi Bian this laminate heated under 100 ℃ on one side, be cut to after vertical 10mm * horizontal 10mm, under 800 ℃, carry out 10 hours unsticking mixture, under 1000 ℃, carry out sintering, thereby make the column laminate shown in 1a.Thereafter, on 2 sides of multi-layer piezoelectric element, with the end of the piezoelectric ceramic that includes electrode tip on this 2 side different mutually mode every the groove of the width 50 μ n of one deck ground formation degree of depth 100 μ n, lamination direction, in this slot part as insulator and filled silicon rubber.

On the opposing party's of uninsulated electrode end face as outer electrode bandedly form thermosetting electric conductor, and carry out 200 ℃ heat treatment thereafter.Thereafter, lead is connected in anodal with outer electrode, negative pole with outer electrode on, and after being coated on silicon rubber on the outer peripheral face of multi-layer piezoelectric element by dipping, apply the polarizing voltage of 1kV, to the processing that polarizes of multi-layer piezoelectric element integral body, thereby obtain as shown in Figure 4 multi-layer piezoelectric element of the present invention.Addendum modification when mensuration applies the voltage of 0～200V to the multi-layer piezoelectric element that obtains, and measure piezoelectricity distortion constant d ₃₃The mensuration of addendum modification is as follows: will be fixed on the vibrationproof platform at the sample that upper surface is puted up aluminium foil, sample is applied the voltage of 0～200V, on the central part of element and 3 positions of periphery, measure the mean value of the value that obtains then to utilize the laser extensometer and estimate.Piezoelectricity distortion constant d ₃₃, use lamination to count n=200 and addendum modification Δ L and apply voltage V=200V, utilize d ₃₃The formula of=Δ L/nV is calculated.

Again, with regard to the amount of Si, utilization can be carried out the quantitative ICP mass analysis of ppm level and carry out quantitatively.With regard to the thickness of grain boundary layer, utilize the TEM image to calculate again.

Again, with regard to the easness of threshing, in pure water, carry out 10 minutes ultrasonic washing, utilize metal microstructure sem observation surface thereafter.

With regard to insulation resistance through the time mensuration that changes with regard to, carry out HALT test (high quicken life cycle test).Mensuration increases and the time of insulation breakdown until leakage current.Condition is to test under 300 ℃ of atmosphere temperature degree, electric field 2kV/mm.

The result is as shown in table 13.

Table 13

Table 13-1

Sample No.	Form
	Form								1-x (mol)	x(mol)	a(mol)	b(mol)	c(mol)	d(mol)	e(mol)	1-a-b- c-d-e (mol)
	^*7-1	0.95	0.05	0.08	0.04	0.04	0.03	0.005	1-x (mol)	x(mol)	a(mol)	b(mol)	c(mol)	d(mol)	e(mol)	1-a-b- c-d-e (mol)	0.805
7-2	^*7-1	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
7-2	7-3	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
7-4	7-3	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
7-4	7-5	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
7-6	7-5	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
7-6	7-7	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
^*7-8	7-7	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
^*7-8	^*7-9	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.805	0.805
^*7-10	^*7-9	0.95	0.05	0.08	0.04	0.04	0.03	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.805
^*7-10	^*7-11	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.795
7-12	^*7-11	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.795
7-12	7-13	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.795
7-14	7-13	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.795
7-14	^*7-15	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.955	0.045	0.085	0.04	0.05	0.025	0.005	0.795	0.795

Table 13-2

No.	Si amount (ppm)	d ₃₃(pm/V)	The time of insulation breakdown (Hr)	Anti-threshing	Grain boundary layer thickness (nm)
No.	Si amount (ppm)	d ₃₃(pm/V)	The time of insulation breakdown (Hr)	Anti-threshing	Grain boundary layer thickness (nm)	^*7-1	150	802	63	○	1.1
7-2	90	810	110	○	0.8	^*7-1	150	802	63	○	1.1
7-2	90	810	110	○	0.8	7-3	70	814	114	○	0
7-4	50	806	123	○	0	7-3	70	814	114	○	0
7-4	50	806	123	○	0	7-5	30	812	130	○	0
7-6	10	801	126	○	0	7-5	30	812	130	○	0
7-6	10	801	126	○	0	7-7	5	793	129	○	0
^*7-8	3	790	124	×	0	7-7	5	793	129	○	0
^*7-8	3	790	124	×	0	^*7-9	0	790	118	×	0
^*7-10	200	760	32	○	1.4	^*7-9	0	790	118	×	0
^*7-10	200	760	32	○	1.4	^*7-11	100	755	56	○	1.1
7-12	90	758	102	○	0.4	^*7-11	100	755	56	○	1.1
7-12	90	758	102	○	0.4	7-13	50	753	100	○	0
7-14	10	740	106	○	0	7-13	50	753	100	○	0
7-14	10	740	106	○	0	^*7-15	0	734	103	×	0

Judge as can be known that from table 13 with regard to sample 7-1,7-10 more than the Si amount 100ppm, 7-11, the grain boundary layer thickness surpasses 1nm, thus until time of insulation breakdown also early.On the other hand, at sample 7-8,7-9, the 7-15 of the not enough 5ppm of Si amount, anti-threshing is low, can see threshing behind processing back or the ultrasonic washing.At Si amount of the present invention is in the scope of not enough 100ppm more than the 5ppm, and the grain boundary layer is below the 1nm, does not change for a long time even apply voltage volume intrinsic resistance, thereby is difficult to cause insulation breakdown.

Again, in above-mentioned manufacture method, consider, add the SiO of ormal weight from the control this point of forming easily ₂, but, then do not adding SiO on one's own initiative if can make in the scope of Si amount not enough 100ppm more than 5ppm of the piezoelectric ceramic behind the sintering ₂Prerequisite under, use to include SiO as impurity morely ₂Also harmless from the beginning of raw material.

Industrial applicibility

As described in above detailed description, multi-layer piezoelectric element of the present invention can long-time continuous drive and good endurance under the environment of high voltage, high pressure, so can be applied in the environment for use fuel injection device strict, for example automobile-use, thereby very high in industrial value.

Claims

1. multi-layer piezoelectric element, it comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, a side internal electrode is connected with outer electrode in first side in the internal electrode of adjacency, and the opposing party's internal electrode is connected with outer electrode in second side; It is characterized in that,

It includes the following alkali metal of the above 300ppm of 5ppm.

2. multi-layer piezoelectric element as claimed in claim 1 is characterized in that, includes the alkali metal below the above 500ppm of 5ppm in described piezoelectric body layer.

3. multi-layer piezoelectric element as claimed in claim 1 is characterized in that, includes the alkali metal below the above 500ppm of 5ppm in described internal electrode.

4. multi-layer piezoelectric element as claimed in claim 1 is characterized in that, includes the alkali metal below the above 500ppm of 5ppm in described outer electrode.

5. as any described multi-layer piezoelectric element in the claim 1～4, it is characterized in that described alkali metal is more than at least a among Na, the K.

6. as any described multi-layer piezoelectric element in the claim 1～5, it is characterized in that, in described multi-layer piezoelectric element, also include the halogens below the above 1000ppm of 5ppm.

7. multi-layer piezoelectric element, it comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, a side internal electrode is connected with outer electrode in first side in the internal electrode of adjacency, and the opposing party's internal electrode is connected with outer electrode in second side; It is characterized in that,

It includes the following halogens of the above 1000ppm of 5ppm.

8. multi-layer piezoelectric element as claimed in claim 7 is characterized in that, includes the halogens below the above 1500ppm of 5ppm in described piezoelectric body layer.

9. multi-layer piezoelectric element as claimed in claim 7 is characterized in that, includes the halogens below the above 1500ppm of 5ppm in described internal electrode.

10. multi-layer piezoelectric element as claimed in claim 7 is characterized in that, includes the halogens below the above 1500ppm of 5ppm in described outer electrode.

11. any described multi-layer piezoelectric element as in the claim 7～10 is characterized in that, described halogens is more than at least a among Cl, the Br.

12. multi-layer piezoelectric element, it comprise piezoelectric body layer and internal electrode alternately the laminate that forms of lamination, be formed at first side of this laminate and the outer electrode on second side respectively, a side internal electrode is connected with outer electrode in first side in the internal electrode of adjacency, and the opposing party's internal electrode is connected with outer electrode in second side; It is characterized in that,

Continuous Drive 1 * 10 ⁹The rate of change of the component size that the component size after more than inferior is preceding with respect to driving is in 1%.

13. multi-layer piezoelectric element as claimed in claim 12 is characterized in that, Continuous Drive 1 * 10 ⁹The rate of change of the gauge of the described internal electrode that the gauge of the described internal electrode after more than inferior is preceding with respect to driving is in 5%.

14. any described multi-layer piezoelectric element as in the claim 1～13 is characterized in that, is added with metal constituent and inorganic composition in described internal electrode.

15. multi-layer piezoelectric element as claimed in claim 14 is characterized in that, described inorganic composition is with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component.

16. any described multi-layer piezoelectric element as in the claim 1～15 is characterized in that described piezoelectrics are principal component with the perofskite type oxide.

17. multi-layer piezoelectric element as claimed in claim 16 is characterized in that, described piezoelectrics are with by PbZrO ₃-PbTiO ₃The perofskite type oxide that constitutes is a principal component.

18. any described multi-layer piezoelectric element as in the claim 1～17 is characterized in that, the sintering temperature of described laminate is more than 900 ℃ below 1000 ℃.

19. any described multi-layer piezoelectric element as in the claim 1～18 is characterized in that, the deviation of the composition in the described internal electrode is below 5% before and after sintering.

20. a multi-layer piezoelectric element, it is lamination piezoelectric body layer and interior electrode layer and constitute alternately; It is characterized in that,

Described piezoelectric body layer is with PbTiO ₃-PbZrO ₃Be principal component, the Si amount is the above and not enough 100ppm of 5ppm.

21. multi-layer piezoelectric element as claimed in claim 20 is characterized in that, described Si is to the segregation of crystallographic grain border, and the thickness on this crystallographic grain border is below 1nm.

22. any described multi-layer piezoelectric element as in the claim 1～21 is characterized in that the metal constituent in the described internal electrode is a principal component with VIII family metal and/or Ib family metal.

23. multi-layer piezoelectric element as claimed in claim 22, it is characterized in that, the amount of the VIII family metal in establishing described internal electrode is the amount of M1 (% quality), Ib family metal when being M2 (% quality), satisfies 0＜M1≤15,85≤M2＜100, M1+M2=100.

24., it is characterized in that described VIII family metal is more than at least a among Ni, Pt, Pd, Rh, Ir, Ru, the Os as claim 22 or 23 described multi-layer piezoelectric elements, Ib family metal is more than at least a among Cu, Ag, the Au.

25. any described multi-layer piezoelectric element as in the claim 22～24 is characterized in that, described VIII family metal is more than at least a among Pt, the Pd, and Ib family metal is more than at least a among Ag, the Au.

26. any described multi-layer piezoelectric element as in the claim 22～25 is characterized in that, described Ib family metal is Cu.

27. any described multi-layer piezoelectric element as in the claim 22～25 is characterized in that, described VIII family metal is Ni.

28. any described multi-layer piezoelectric element as in the claim 1～27 is characterized in that described internal electrode includes the space, is 5～70% with respect to the area ratio whole sectional area, that the space is occupied in the cross section of described internal electrode.

29. as any described multi-layer piezoelectric element in the claim 1～27, it is characterized in that, on described first side, between the end of described the opposing party's internal electrode and described outer electrode, be formed with groove, in this groove, be provided with insulator, on described second side, between the end of a described side's internal electrode and described outer electrode, be formed with groove, be provided with insulator in this groove, described insulator is lower than described piezoelectrics Young's modulus.