JPS6242472A - Electrostriction element - Google Patents

Abstract

PURPOSE:To obtain a low-hysteresis electrostriction element for ultra-precision positioning by substituting Ba for part of the lead atoms of a porcelain composition which generates a large field-induced strain. CONSTITUTION:A porucelain material expressed by Pb[(Mgl/3Nb2/3)1-xTix]03 (0.05<=x<=0.15) generates a large field-induced strain and is suitable as an electrostriction element. If, in Pb[(Mgl/3Nb2/3)1-xTix]03, x is less than 0.05, the field-induced strain is small, and it is thus not suitable as an electrostriction element. Further, if x exceeds 0.15, the hysteresis becomes large. In order to make this hysteresis small, Ba is substituted for part of the Pb atoms. The amount of Ba to be substituted for Pb is preferably on the order of 2atm% of the Pb atoms. If it exceeds 4atm%, the field-induced strain becomes small. Although even a small amount of Ba substitution is effective, it is to be 1atm% or more for practival use. By adopting a porcelain material of large field- induced strain and small hysteresis, an electrostriction element for ultra-precision positioning can be obtained.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an electrostrictive element.

[Technical background of the invention and its problems]

Conventionally, Pb has been used as an actuator for ultra-precision positioning.
(Mgl/3Nb2/3)An electrostrictive element is known that utilizes electric field-induced strain in a ceramic material having Oat as its main component.

Especially Pb (Mg 1/3Nb 2/3) 050T
The electric field induced strain of lo, 1o)03 is.

It is known to have a size comparable to that of Pb(Zrt-1Tiz)03-based piezoelectric materials.

However, Pb [(Mg1/3Nb2/3) Osjo
The electric field-induced strain of Tlo10]03 had a large hysteresis in the relationship with the electric field strain, and it was difficult to precisely control the amount of displacement using voltage.

[Purpose of the invention]

An object of the present invention is to provide an electrostrictive element with small hysteresis in the pressure-displacement relationship.

[Summary of the invention]

The present invention is a porcelain that generates large electric field-induced strain*
Pb [(Mg1/3Nb2/3)1-x'rtx)o
3 co, os ≦ This is an electrostrictive element that achieves the above objectives by employing the above-mentioned method.

Pb [(Mg1/3Nb2/3) 1-xTlK)03
If X in Ilc is less than 0.05, the electric field induced strain will be small, making it unsuitable for use as an electrostrictive element. Moreover, when X exceeds 0.15, the hysteresis increases, so the Ba according to the present invention
Even with the substitution of , it is difficult to remove this hysteresis.

Also, regarding the amount of BaO to replace Pb, the za of the Pb atom
It is desirable that the thickness be around tm. If it exceeds 4 atm, the electric field induced strain will become small. Although a small amount of Ba is effective when substituted, it is practically preferable to use 11 Ltm or more.

Typical examples of the electrostrictive element include a laminated electrostrictive element that utilizes the longitudinal electrostrictive effect of the above-mentioned ceramic composition and a bimorph electrostrictive element that utilizes the transverse electrostrictive effect of the ceramic composition.

〔Effect of the invention〕

According to the present invention, by employing a ceramic material having large electric field-induced strain and small hysteresis, it is possible to provide an electrostrictive element for ultra-precision positioning that can be made smaller in element shape and does not require a feedback mechanism. .

[Embodiments of the invention]

The present invention will be explained in detail below.

The porcelain material employed in the present invention was manufactured by a common powder metallurgy method. That is, PbO, TiO2゜MgO,
Raw materials such as Nb2O5 and BaCO3 were accurately weighed onto a predetermined mesh, and mixed well using a ball mill.

Next, the mixture was preliminarily calcined at a diopter of 800 to 850°C, and further pulverized using a ball mill to obtain a prepared powder.

After that, water or a binder such as polyvinyl alcohol was added to this powder to form a powder with a diameter of 251 m and a thickness of 2 r.
Pressure molded into a disc shape of about t + ra, 1150 ~ 125
It was fired at a temperature change of about 0'O. The sintered sample has a diameter of 2
It was polished to a thickness of 0.0 mm and a thickness of 0.5 mm, and 1 pole was baked on both sides. Twenty of these disks were laminated with a conductive adhesive, and positive and negative lead wires were taken out alternately from the electrodes of every other layer. The laminated electrostrictive cable produced as described above is shown in FIG. 2.

Figure 1 shows the displacement characteristics when a 0.1 Hz ±500 V triangular wave voltage was applied to this element. A non-contact linear displacement potentiometer was used to detect displacement. X in the diagram
The value of (Pb 1-xBaz) of the adopted porcelain material [
(Mg1/3Nb2/3) ogoTlo, to] represents the Ba1iffi transition in o3.

From FIG. 1, it is clear that as the Bafi conversion amount increases, the hysteresis decreases and decreases to an almost negligible bond at x-0.02. If the Batft exchange amount is increased too much, the displacement position tends to become smaller, and it gradually becomes unsuitable as an electrostrictive rope.

[Brief explanation of the drawing]

The f$1 diagram is (Pb 1-zBaz ) ((Mg 1/
3Nb 2/3 )o, 9oTio, to )03 A diagram showing voltage-displacement characteristics of a product/1ffl electrostrictive element using a ceramic material in which X is varied in the composition. FIG. 2 was used to measure the characteristics shown in FIG. FIG. 3 is a diagram showing the structure of a stacked electrostrictive element. Agent Patent Attorney Nori Chika Yudo Kikuo Takehana

Claims (2)

[Claims] (1) Pb [(Mg_1_/_3Nb_2_/_3)_
1_-_xTi_x)O_3 (0.05≦0.15)
An electrostrictive element characterized in that it uses a porcelain material in which atm% or less is replaced with Ba. (2) The electrostrictive element according to claim 1, wherein the amount of Ba is 1 atm% or more.