JPS6086884A - Manufacture of electrostrictive-effect element - Google Patents

Abstract

PURPOSE:To obtain a favorable insulating coated film by a method wherein, when glass powder is made to stick to the exposed parts of internal electrode layers by an electrophoresis method, inactive gas is made to ventilate in a suspension before DC voltage is impressed or/and during a time when the DC voltage is being impressed. CONSTITUTION:A laminated body constituted by laminating alternarly internal electrodes 3 and 4 and electrostrictive material 1 and 2 is manufactured in such a way that the internal electrodes 3 and 4 are made to expose at the surface of the laminated body and the back surface thereof. The electrodes 3 and 4 are made to connect alternately with temporary electrodes 5 and 6 provided on the sides of the laminated body every one layer. One side of the laminated body is covered with an adhesive tape and the laminated bdy is installed in an electrified glass powder-containing suspension along with an opposed electrode plate (not shown in the diagram). DC voltage is impressed in between the temporary electrode 5 and the opposed electrode plate, and glass powder 7 is made to stick to the internal electrodes 3 and the electrostriction material in the vicinities thereof. Before the voltage impression is performed or/and during a time when the voltage impression is being performed, inactive gas is made to ventilate in the suspension. When the laminated body obtained in such a way is baked, a dense glass coated film having high insulating withstand voltage can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an electrostrictive element using longitudinal effect.

In the structure of an electrostrictive element that utilizes the longitudinal effect, it is necessary to have internal electrodes that are the same size as the entire cross section of the element in order to prevent stress concentration when strain occurs by generating an electric field throughout the electrostrictive material. be. In addition, in order to generate a high electric field at low voltage and obtain large strain, the distance between the internal electrodes should be set to 100 mm.
It is necessary to reduce the thickness to about microns. For the above two reasons, it is very difficult to electrically connect an electrostrictive element having an internal electrode having the same area as the cross section of the element.

Therefore, the present inventors first developed an electrical connection method characterized by forming an insulator every other layer on the internal electrode layer exposed on the end face of the electrostrictive material laminate and the ceramic in its vicinity by electrophoresis. proposed.

FIG. 1 is an external view of an electrostrictive effect element connected by this method. An insulator 7 is formed every other layer by electrophoresis on the internal electrode layer exposed on the end face and the ceramic in the vicinity thereof. An insulator 8 is also formed on the inner electrode shifted by one layer on the end face on the back side. A band-shaped external electrode 11 is formed across this insulator and the exposed internal electrode 4. By similarly forming external electrodes for the internal electrodes 3 on the back side, a large number of internal electrodes are connected to the positive side terminal 13 or the negative side terminal 12 at every other layer. By applying a DC voltage between these external terminals, a uniform electric field is generated throughout the electrostrictive material 2 except for the protective film portion 1, and the element is expanded in parallel to the stacking direction. Since there is no stress concentration, the element will not be destroyed even if voltage is applied repeatedly, and since the distance between internal electrodes is as short as about 100 microns, it can be driven at a low voltage of 100 V or less.

A method for manufacturing this element will be briefly explained.

First, the internal electrode 3.4 and the electrostrictive material 1 as shown in FIG.
．． A laminate in which 2 and 2 are alternately stacked is manufactured by applying manufacturing technology for multilayer ceramic capacitors.

A large number of internal electrodes 3, 4 are exposed on the front and back end surfaces, and are alternately connected to two temporary external electrodes 5.6 formed on the side surfaces at every other layer. This laminate and a metal plate for a counter electrode were placed in the suspension.

When a DC voltage is applied from this counter electrode plate toward the temporary external electrode 5, the positively charged glass powder in the suspension adheres to the internal electrode 3 and the electrostrictive material in its vicinity by electrophoresis.

FIG. 3 is an external view of a laminate with glass powder adhered to the front end face. In the figure, numeral 1 indicates an electrostrictive material that functions as a protective film, and numeral 2 indicates an electrostrictive material in a portion where an electric field is generated to cause distortion. 4 indicates exposed internal electrodes, and the internal electrodes present between them are covered with a band-shaped glass powder deposit 7. After the glass powder is baked and fixed, the glass powder is also attached to the end face of the back side in the same manner, and the glass powder is baked and fixed to form a glass coating. The laminated body with the glass coating formed thereon is cut at the position shown by the broken line in FIG. 4, and when the external electrodes 11 are formed on several pieces 1o excluding the pieces 9 at both ends, the electrodes shown in FIG. 1(a) are formed. A distortion effect element is obtained.

The problem with this method is that sometimes suspensions with very poor adhesion are obtained, and suspensions that initially had good adhesion quickly become adhesive in a short period of time after use. The problem is that the adhesive will not adhere at all, or that the adhesive will only have a lot of cuts and constrictions. The reason is thought to be that oxygen in the air dissolves into the suspension and changes the charging state of the glass powder. Since the suspension is prepared by mixing and dispersing using a high-speed homomixer, oxygen in the air is taken in and easily dissolved. Furthermore, during electrophoretic deposition work, samples and jigs are taken in and out while exposed to the outside air, so oxygen in the air is likely to be trapped.

An object of the present invention is to provide a method for manufacturing an electrostrictive element that solves the above-mentioned drawbacks.

In the present invention, in a suspension containing charged glass powder,
All or part of the internal electrode layer of the laminate of the electrostrictive material and the internal electrode is used as one electrode, and the counter electrode plate is used as the other electrode, and a DC voltage is applied between both electrodes. In the method for manufacturing an electrostrictive element, the method includes the step of depositing the charged glass powder on all or a portion of the exposed portion of the internal electrode layer on the surface of the laminate and the electrostrictive material in the vicinity, wherein a direct current is applied during the step. The preamble to the application of tonnage pressure is/and a method for manufacturing an electrostrictive element in which an inert gas such as nitrogen is passed through the suspension during application. This makes it possible to obtain a good belt-like adhesion that has sufficient width and thickness and is free from cuts and constrictions.

The method is simple; all you need to do is blow out an inert gas such as nitrogen from a pipe installed in the suspension. 200 before applying voltage
A suspension with good adhesion is obtained by bubbling at liters per hour for 1 hour.

Also, 150 when voltage is applied! By flowing inert gas at a rate of about J liters per hour, good results can always be obtained even if non-adherence is performed continuously for about 6 hours. When a voltage is applied, a steady flow occurs in the suspension due to mass transfer accompanying an electrochemical reaction, creating a region with a weak electric field, which may cause partial adhesion to occur. In order to prevent this and obtain good adhesion to the entire end face of the laminate, it is necessary to stir the suspension, but there is a problem in that the mixing deteriorates the adhesion due to the dissolution of oxygen.

By applying the method of the present invention and bubbling nitrogen gas at the same time as the suspension when voltage is applied, fatigue of the suspension is eliminated and good adhesion can be obtained during long-term work.

Hereinafter, the present invention will be explained in detail according to examples.

First, an electrostrictive material laminate having a structure as shown in FIG. 2 and having a large number of internal electrodes and a set of temporary external electrodes is manufactured by the following method.

Magnesium lead niobate (Pb(Mg%NbX)Os
) and lead titanate (PbTi0. ) and lead titanate (PbTi0. ) as the main components.

A slurry was prepared by dispersing this in an organic solvent. This slurry was coated onto a Mylar film to a thickness of 100 microns using a casting film-forming device used in the production of conventional multilayer ceramic capacitors and dried. This was peeled off from the film to obtain an electrostrictive material green sheet.

Some of the green sheets were further screen-printed with platinum paste as internal electrodes. After stacking several dozen of these green sheets and pressing them together using a heat press, 12
It was fired at 50°C to obtain an electrostrictive material laminate. This was cut at a position where the internal electrodes were exposed on the surface every other layer, temporary external electrodes were applied and baked, and the sides were cut to obtain a laminate with exposed internal electrodes as shown in Figure 2. . Electrophoresis is applied to the electrostrictive material laminate thus obtained. In FIG. 2, reference numeral 1 indicates the electrostrictive material of the protective film portion, and reference numeral 2 indicates the electrostrictive material that causes strain. The inner electrodes 3, 4 are connected to temporary outer electrodes indicated at 5 and 6, respectively, and the other inner electrodes are connected to two temporary outer electrodes alternately in every other layer.

Next, a suspension containing glass powder as deposits is prepared by the following method. Zinc borosilicate crystallized glass powder 30g
, ethanol 290mA! , 10 ml of the 54 El element ethanol solution is mixed with a high-speed homogenizer.

Iodine acts as an electrolyte, and the glass powder is positively charged. After applying ultrasonic waves for 30 minutes, the mixture was allowed to stand for a minute to remove the precipitate. Six such suspensions were prepared and used in the experiments described below.

For comparison, the three suspensions were pretreated with nitrogen gas bubbling at 2007/hr for 1 hour. Then, for each of the untreated and pretreated suspensions, the suspension was heated at 20 V aoo seconds under three conditions: ∎ static state, ∎ stirring, and ∎ bubbling nitrogen gas at 1,501 times per hour while stirring. Deposition was performed by applying a direct current voltage.

FIGS. 5 to 8 are external views showing how to assemble and connect an electrophoresis device when bubbling nitrogen gas and nitrogen gas. FIG. 5 shows the arrangement of the electrostrictive material laminate 22, which is arranged with the end surface to be attached inside the cylindrical container 21 facing outward. Cover the edges that you do not want to stick with adhesive tape to protect them. Attach the conductor portion to the temporary external electrode made up of the internal electrodes to be attached. FIG. 6 shows the electrical connection method.

After the conductive wires are collected in a ring 25, they are connected to the negative terminal of the DC power supply path. A cylindrical counter electrode is installed between the end face of the laminate and the container, and is connected to the positive terminal 27 of the DC power source. FIG. 7 shows the method of kakuhan and bubbling. A stainless steel tube blade with an inner diameter of 5 m is introduced into the suspension 29 and is used to bubble nitrogen gas. The rotation is performed by rotating the stainless steel blade 31. FIG. 8 shows an electrophoresis device in which all of these components are assembled and connected. The stainless steel vanes are rotated by a motor 32 to agitate the suspension.

Using the above apparatus, electrophoretic deposition was repeatedly performed using a large number of electrostrictive material laminates, and the uniformity of the deposition within the end face was improved.
Adhesion was comprehensively investigated with respect to four items: breakage and constriction, fatigue of the suspension, and settling of glass powder. The table summarizes the results. An X mark indicates that the product is defective, a Δ mark indicates that the condition is sometimes deteriorated, a ◯ mark indicates that the condition is generally good, and a ◎ mark indicates that the condition is very good.

Looking at these results, it is clear that it is necessary to constantly bubble nitrogen gas during voltage application, and that bubbling nitrogen gas is also effective as a pretreatment.

In order to form band-shaped glass powder accurately and stably on the end face of an electrostrictive material laminate by electrophoresis, it is necessary to maintain a good electrical charge state of the glass powder in the suspension, and to create a turbulent flow to form a uniform band-shaped glass powder. Two important points are that the adhesion be formed on the entire end surface, and bubbling of the suspension with an inert gas such as nitrogen gas has a great effect. By using this method,
An excellent insulating film can be formed, and electrostrictive elements with high dielectric strength and good electrical connections can be stably manufactured.

[Brief explanation of the drawing]

FIG. 1 is an external view of an electrostrictive effect element in which electrical connections are made using an insulating film using an electrophoresis method. Number 1 in the diagram
2 indicates the electrostrictive material of the protective film portion, 2 indicates the electrostrictive material of the portion where strain is generated, 3.4 indicates the internal electrode, and 7.8 indicates the insulating film formed by electrophoresis. 11 is an external electrode, 12.1
3 indicates external connection terminals on the negative side and the positive side, respectively. FIG. 2 is an external view of an electrostrictive material laminate with temporary external electrodes for applying the electrophoresis method. Number 5.6 in the figure indicates a temporary external electrode in which 4tl of internal electrodes are connected to each other at every other layer. FIG. 3 shows an electrostrictive material laminate in which glass powder is deposited every other layer on the internal electrode exposed portion, its periphery, and one ceramic layer. Number 7 in the figure indicates the attached glass powder. FIG. 4 is an external view showing an electrostrictive material laminate with 1.11 bales of glass formed on both end faces and its cutting position. In the figure, numeral 9 indicates the unusable small piece %lO at both ends which can be used as an electrostrictive effect element. FIG. 5 is an external view showing a method of installing an electrostrictive material laminate. In the figure, numeral 21 represents a container, 22 represents a laminate, and numeral 21 represents a conductive wire. FIG. 6 is an external view showing the electrical connection method. In the figure, the number B indicates a counter electrode plate, A indicates a connecting ring, 26 indicates a negative terminal, 27 indicates a positive terminal, and A indicates a DC power supply. FIG. 7 is an external view showing the method of stirring and bubbling. In the figure, number 29 indicates a suspension % of 30, a stainless steel tube, and 31 indicates a stainless steel blade. FIG. 8 is an external view showing the entire assembled and connected electrophoresis device. Number 32 in the figure indicates a motor. Figure 1 13 Figure 2 Figure 53 Figure L/- Figure 5? ? Figure 1111 Figure 7 Figure 3

Claims (1)

[Claims] In a suspension containing charged glass powder, all or part of the internal electrode layer of the laminate of electrostrictive material and internal electrodes is used as one electrode, and the counter electrode plate is used as the other electrode, and a direct current is applied between both electrodes. An electrostrictive effect element comprising the step of applying a voltage and depositing the charged glass powder on all or part of the exposed portion of the internal electrode layer on the surface of the laminate and the electrostrictive material around it by electrophoresis. A method for manufacturing an electrostrictive element, characterized in that an inert gas such as nitrogen is passed through the suspension before and/or during the application of a DC voltage during the step.