JPH03280479A - Manufacturing method of multilayer ceramic electrostrictive element - Google Patents

Abstract

PURPOSE:To remove organic contaminants attached to the rugged side face of an element so as to prevent a discharge from starting in an atmosphere of high humidity by a method wherein a laminated ceramic sintered body on which an external electrode has been formed is cut off, and the separated sintered ceramic body is subjected to ultrasonic cleaning by the use of organic solvent, which is thermally treated. CONSTITUTION:Conductive paste is printed on a ceramic body vertical to an insulating layer 7, which is burned at a maximum temperature of 590 deg.C for 10 minutes to form an outer electrode 8, and thus a laminated ceramic sintered body 6 is manufactured. The laminated ceramic sintered body 6 is cut in a direction vertical to the insulating layer 7 or in the direction of Y1-Y2 conforming to the width of an element to serve as a laminated ceramic electrostrictive element 9. The laminated ceramic electrostrictive element 9 is subjected to ultrasonic cleaning in trichloroethane for 30 minutes, then thermally treated at a maximum temperature of 590 deg.C for 15 minutes to completely remove organic substances such as oil and others, and in succession sheathed with epoxy resin to finish the formation of a laminated ceramic electrostrictive element.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a multilayer ceramic electrostrictive element.

(Prior art) Conventional multilayer ceramic electrostrictive elements are produced by firing a laminate made by alternately stacking sheet-like electrostrictive ceramic members and internal electrode conductors and pressurizing them at high heat. A sintered body is provided with an insulating layer that insulates one end surface of the internal electrode conductor exposed on each side surface every other layer on each side surface, and the other exposed end surface of the internal electrode conductor is electrically insulated. A pair of external electrodes that are connected to form two comb-shaped electrodes is formed for each laminated ceramic electrostrictive element, and then each element is cut, washed, dried, and then covered with resin. It was manufactured.

(Problems to be Solved by the Invention) The conventional method for manufacturing the multilayer ceramic electrostrictive element described above is as follows:
During the process from cutting the multilayer ceramic sintered body with external electrodes formed to applying the exterior resin, ultrasonic cleaning is performed in an organic solvent to remove the adhesive, oil, and abrasive grains used during cutting. However, cleaning alone does not completely remove dirt, and in particular, dirt is difficult to remove from the side surface of the multilayer ceramic electrostrictive element where the external electrodes are formed due to unevenness along the insulating layer. Furthermore, the internal electrodes exposed on the cut surface of the laminated ceramic electrostrictive element immediately after cutting are chemically active, so when a voltage is applied to the laminated ceramic electrostrictive element coated with resin in a high humidity atmosphere, Hydrolyzable chlorine ions in the resin are likely to be liberated, and as a result, the multilayer ceramic electrostrictive element has a disadvantage in that its surface resistance decreases and discharge is likely to occur on its side surfaces.

(Means for Solving the Problems) In the method for manufacturing a laminated ceramic electrostrictive element of the present invention, after the step of cleaning the laminated ceramic electrostrictive element divided into individual elements, the laminated ceramic electrostrictive element is cleaned. This process includes a heat treatment process to remove organic contaminants and to inactivate the end surfaces of the internal electrode conductors exposed on the sides of the board.

[Function] Therefore, ultrasonic cleaning removes organic stains that cannot be completely removed, and also prevents the release of hydrolyzable chlorine ions in the resin by the end surfaces of the internal electrode conductors exposed on the sides. It can be prevented.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing an internal electrode conductor and a laminated structure of an embodiment of the method for manufacturing a laminated ceramic electrostrictive element of the present invention;
Fig. 2 is a perspective view of a laminated ceramic sintered body laminated with the piezoelectric sheet 1a with an internal electrode conductor formed with the internal electrode conductor of Fig. 1, and Fig. 3 is a perspective view of the laminated ceramic sintered body of Fig. 2. 4 is a perspective view showing a state in which a temporary electrode is formed; FIG. 4 is a perspective view showing a state in which the laminated ceramic sintered body of FIG. 3 is cut with the length of the element as the width; FIG. FIG. 6 is a perspective view showing a state in which an insulating layer and an external electrode are formed on a multilayer ceramic sintered body, and FIG. 6 is a perspective view of a multilayer ceramic electrostrictive element.

In the manufacturing process of the laminate, a piezoelectric sheet 1a with internal electrode conductors 2 formed thereon is created by printing a conductive paste on one side of the surface of the piezoelectric sheet 1, leaving a part of a band-shaped portion. A piezoelectric sheet 1a with an internal electrode conductor is placed under the piezoelectric sheet 1 that is not formed with an internal electrode conductor, and further the internal electrode is placed so that the strip-shaped part that is not formed with an internal electrode conductor is located on the opposite end surface. Piezoelectric sheets 1a with conductors are arranged and laminated (FIG. 1). This laminate was heated at a pressure of 290 kg/cm2. After thermocompression bonding at a temperature of 110° C. for 1 hour and 70 minutes, sintering is performed at a maximum holding temperature of 1120° C. and a holding time of 2 hours to produce a multilayer ceramic sintered body 3 (FIG. 2). A conductive paste is printed on the surface of the laminated ceramic sintered body 3 where the internal electrodes are exposed every other layer and fired at a temperature of 500°C for 1 hour to form temporary electrodes to form an insulating layer. 4 to form a laminated ceramic sintered body 3a (FIG. 3). Next, this sintered body 3a is cut in the X and -X directions to match the length of the electric element r, to obtain a multilayer ceramic sintered body 5 (fourth
[Ne1). This laminated ceramic sintered body 5 is immersed in an ethanol solution of glass powder dispersed with a stirrer, and the glass powder is electrodeposited on every other layer on the internal electrodes by electrophoresis under the conditions of 20 x 1 hour and 3 minutes of DC current. After that, the insulating layer 7 is baked under the conditions of a maximum holding temperature of 615°C and a holding time of 15 minutes.
form. Next, a conductive paste is printed orthogonally to the insulating layer 7, and is fired at a maximum holding temperature of 590° C. and a holding time of 10 minutes to form an external conductor Nj8 to produce a multilayer ceramic sintered body 6 ( Figure 5). This multilayer ceramic sintered body 6 is aligned with the element width in a direction perpendicular to the insulating layer 7 (YI
(Y2 direction) to obtain a multilayer ceramic electrostrictive element 9 (FIG. 6). This laminated ceramic electrostrictive element 9 was ultrasonically cleaned in trichloroethane for 30 minutes, and then heat treated in air at a maximum holding temperature of 590°C and a holding time of 15 minutes to completely remove oil and other organic substances. Next, the exterior is covered with epoxy resin to complete the multilayer ceramic electrostrictive element.

Next, a method of manufacturing a multilayer ceramic electrostrictive element having a capacitor structure using another internal electrode conductor forming method will be described.

FIG. 7 is a diagram showing a method for forming internal electrode conductors of a laminated ceramic electrostrictive element having a capacitor structure, and FIG. 8 is a piezoelectric sheet 12a with internal electrode conductors shown in FIG. 7.

Internal electrode conductor 1 of multilayer ceramic sintered body consisting of 12b
2a, a vertical cross-sectional view in the direction perpendicular to 12b, FIG.
FIG. 2 is a longitudinal cross-sectional view in a direction perpendicular to the internal electrodes of a multilayer ceramic electrostrictive element having a capacitor structure in which external electrodes are formed on the multilayer ceramic sintered body shown in the figure.

In the laminate manufacturing process, as shown in FIG.
The side end surfaces of the internal electrode conductors are intermittently exposed on both sides in the p and -p2 directions of the conductor, and the conductive paste is printed in a plurality of rectangular patterns having sides corresponding to the vicinity of the center line, thereby forming a plurality of internal electrodes. A piezoelectric sheet 1b with an internal electrode conductor on which the conductor 12a is formed, and a rectangular sheet that is not exposed on all sides of the piezoelectric sheet 1b, is long in the p and -p2 directions, and has the same width as the internal electrode conductor 12a in the Q1Q2 direction. , a piezoelectric sheet IC with a plurality of internal electrode conductors +2b is formed by printing a conductive paste on a plurality of rectangular patterns arranged so as to overlap in a vertical plane. Stack them alternately on the bottom (Figure 7). This laminate is thermocompressed and sintered to produce a sintered body in the same manner as in the manufacturing process of the laminated ceramic sintered body 3. This sintered body is placed perpendicularly to the internal electrode conductor.
Cut in the P and -P2 directions at the center line in the Q and -Q2 directions shown in FIG. A multilayer ceramic sintered body IO is produced (FIG. 8). Internal electrode conductors 12a, 12b are provided on each side surface of the sintered body IO where the side end surfaces of the internal electrode conductors 12a, 12b are exposed.
External electrode 1 was formed by printing a conductive paste orthogonally to +2b and baking it at a maximum holding temperature of 590°C and a holding time of 10 minutes.
3 to form a multilayer ceramic electrostrictive element 11 having a capacitor structure (FIG. 9). This multilayer ceramic electrostrictive element 1
1 is cleaned and heat treated in the same manner as for the laminated ceramic electrostrictive element 9 to complete the laminated ceramic electrostrictive element 11 having a capacitor structure.

The multilayer ceramic electrostrictive element produced in this way was
0°C, 90-95 RH (7)” CDCI
50V17) Hals (frequency 250Hz) load 50
Even when the voltage is applied for 0 hours, there is no decrease in the insulation resistance between the external electrodes and no discharge occurs.

〔Effect of the invention〕

As explained above, in the present invention, an insulating layer that was not removed even after cleaning is formed by cutting a multilayer ceramic sintered body on which external electrodes are formed, ultrasonically cleaning it with an organic solvent, and then heat-treating it. Organic stains on the uneven side surfaces of the element are removed, and the activity of the exposed end faces of the internal electrodes is significantly reduced, which has the effect of preventing discharge from occurring in a high humidity atmosphere.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an internal electrode conductor and a laminated structure of an embodiment of the method for manufacturing a laminated ceramic electrostrictive element of the present invention;
FIG. 2 is a perspective view of a multilayer ceramic sintered body in which piezoelectric sheets 1-1a with internal electrode conductors are laminated, and FIG. 3 is a multilayer ceramic sintered body of FIG. A perspective view showing a state in which temporary electrodes are formed on the structure, and FIG.
Fig. 5 is a perspective view showing the multilayer ceramic sintered body shown in Fig. 4 cut with the length of the element as its width; FIG. 6 is a perspective view of a multilayer ceramic electrostrictive element, FIG. 7 is a diagram showing a method for forming internal electrode conductors of a multilayer ceramic electrostrictive element with a capacitor structure, and FIG. 8 is a diagram showing the inside of a multilayer ceramic sintered body. Longitudinal cross-sectional view perpendicular to the electrode conductor, 'f,
FIG. 9 is a vertical cross-sectional view of a multilayer ceramic element having a capacitor structure in which external electrodes are formed on the multilayer ceramic sintered body of FIG. 8 in a direction perpendicular to the internal electrodes. 1...Piezoelectric sheet, 1 a, 1
b, 1 c...piezoelectric sheet with internal electrode conductor, +2
a, +2b...Inner electrode conductor, 3.3a, 5.
6... Multilayer ceramic sintered body, 4......
...Temporary electrode, 7...Insulating layer, 8.13...External mold rod,

Claims (1)

[Scope of Claims] 1) A laminated ceramic sintered body in which sheet-like piezoelectric ceramic members and internal electrode conductors are alternately stacked, internal electrodes each exposed on a pair of opposing sides of the laminated ceramic sintered body. After forming an external electrode that electrically connects an insulating layer that insulates every other layer on one end surface of the conductor and the other exposed end surface of the internal electrode conductor to constitute two comb-shaped electrodes, the laminated ceramic sintered In a method for manufacturing a multilayer ceramic electrostrictive element, the structure is divided into individual elements including a pair of external electrodes, the plurality of divided elements are cleaned at once, and then each element is covered with resin. Next to the step of cleaning the multilayer ceramic electrostrictive element that has been divided into elements, organic stains adhering to the multilayer ceramic electrostrictive element are removed, and the end surfaces of the internal electrode conductors exposed on the sides of the element are cleaned. A method for manufacturing a multilayer ceramic electrostrictive element, comprising a heat treatment step for activating it.