JP5146332B2 - Degreasing method - Google Patents

Description

  The present invention relates to a degreasing method and a degreasing jig for degreasing a degreased body such as a ceramic molded body.

  A multilayer ceramic element used for an electronic component or the like is generally manufactured by placing a ceramic molded body produced using a press molding method or the like on a plate called a setter and performing degreasing and firing. At this time, it is desirable to remove a binder, a solvent and the like in the ceramic molded body as much as possible by degreasing. However, it is difficult to degrease the setter mounting surface in the degreasing process, and there is a tendency that a large amount of carbon component remains. When the residual carbon increases, the residual carbon evaporates in the firing process after the degreasing process, and thus the sinterability of the ceramic is suppressed, and the shrinkage difference occurs due to friction with the setter, causing deformation and cracks. There is.

  In order to solve these problems, a method of increasing the center line surface roughness of the setter mounting surface has been proposed (see, for example, Patent Document 1). By increasing the roughness of the center line surface of the setter mounting surface, the mounting surface can be easily degreased and carbon can be removed uniformly.

  On the other hand, in the case of a multilayer ceramic element constituted by using a base metal such as copper (Cu) or nickel (Ni) as an internal electrode for cost reduction, degreasing of the multilayer molded body is a reduction in order to prevent oxidation of the base metal. Performed in an atmosphere. In this case, unlike the degreasing in the atmosphere, since the oxidation reaction of the organic matter is unlikely to occur, the organic matter is removed by applying as much water vapor as possible to the reducing gas to the molded body. For example, a 9 × 9 × 40 mm size or the like In the case of this large shaped molded body, as shown in Patent Document 1, even when a setter having a rough center line surface is used, it is difficult to degrease the mounting surface. In particular, in the case of a piezoelectric multilayer ceramic element or the like containing PbO in the ceramic layer and Cu in the electrode layer, in addition to the above problems, the organic matter (residual carbon) remaining without being degreased has a controlled reducing atmosphere. Further reduction causes PbO in the ceramic layer to become Pb, and this Pb causes a eutectic reaction with Cu in the electrode layer to cause melting.

  In order to solve these problems, as shown in the plan view of FIG. 10 and the front view of FIG. 11, the mounting surface of the setter 101 is formed in a corrugated shape by unevenness, and the ceramic molded body 102 to be placed is There is a proposed example of improving the degreasing property by providing the gas permeability of the degreasing gas (see, for example, Patent Document 2).

JP 2006-8497 A JP 2007-227482 A

  However, in the case of the method of Patent Document 2, since the large-sized ceramic molded body 102 is laid and placed on the setter 101, the number of placements per area is small and productivity is lowered. Therefore, in accordance with the method disclosed in Patent Document 1, as shown in FIG. 12, if a plurality of setters 101 on which ceramic molded bodies 102 are mounted are stacked in the height direction via spacers 103, productivity is increased. Can be improved. However, in such a method, there is a problem that as the lower side is reached, the reducing gas does not spread uniformly over the ceramic molded body 102 and the degreasing property is lowered.

  The present invention has been made in view of the above, and provides a degreasing method and a degreasing jig capable of satisfactorily performing degreasing on a plurality of degreased bodies capable of ensuring productivity. With the goal.

In order to solve the above-described problems and achieve the object, the degreasing method according to the present invention includes a plurality of degreased bodies having the same shape and formed in the shape of a rectangular parallelepiped having a uniform thickness in the longitudinal direction. Parallel and perpendicularly arranged in a two-dimensional plane perpendicular to the longitudinal direction, and with a gas permeability through the longitudinal direction of each degreased body with respect to the degreased gas, insertion and removal in the longitudinal direction A degreasing jig comprising a first support member and a second support member that are partially supported in at least two locations in the longitudinal direction and a spacer so as to be freely used, and the first support member is placed vertically is the having said end face is placed face which gave gas permeable penetrating in a direction perpendicular to the end face while supporting partially contacts touch state of each of the degreased body, the second supporting member , Disposed above the first support member, and In a state where the fat bodies are vertically placed on the placement surface, the longitudinal directions are parallel to each other, and are formed in a lattice shape so as to be supported evenly arranged in a horizontal plane so that the respective degreased bodies can be inserted and removed. The spacer has a plurality of openings, and the spacer is disposed on one surface side of the first support member and the second support member, and the first support member is provided at a predetermined height position from the installation surface. is intended to provide a second support member to a predetermined height position above the first support member, a plurality of the object to be degreased body, respective adjacent for imparting gas permeability in the longitudinal direction parallel to each other A supporting step of uniformly arranging and supporting in a two-dimensional plane orthogonal to the longitudinal direction of the degreased body so that the space is uniform, and the degreased body supported by the degreasing jig Along the longitudinal direction from one end to the other end A degreasing step of flowing a degreasing gas degreased of the object to be degreased body to said adjacent space to characterized in that it comprises a.

  The degreasing method according to the present invention is characterized in that, in the above invention, the step of degreasing the degreased body is performed in a reducing atmosphere.

  The degreasing method according to the present invention is characterized in that, in the above-mentioned invention, the degreased body contains a lead-based piezoelectric material.

  The degreasing method according to the present invention is characterized in that, in the above invention, the degreased body is a laminated piezoelectric body including an internal electrode made of copper.

The degreasing method according to the present invention is characterized in that, in the above-described invention, each opening of the second support member is formed to be larger by a predetermined dimension than the size of the horizontal cross section of the degreased body placed vertically. And

  According to the degreasing method and the degreasing jig of the present invention, for a plurality of degreased bodies, the degreasing gas is distributed so that the flow resistance distribution is uniform along each longitudinal direction and penetrates from one end side to the other end side. Since it flows, degreasing gas spreads uniformly with respect to each degreased body, and there is an effect that a plurality of degreased bodies that can ensure productivity can be degreased with good uniformity.

FIG. 1 is a schematic perspective view showing an example of a multilayer ceramic element which is an object of the manufacturing method of the present invention. FIG. 2 is a longitudinal side view showing an example of a laminated state of the piezoelectric layer and the internal electrode layer of the multilayer ceramic element. FIG. 3 is a perspective view showing a configuration example of the degreasing jig according to the first embodiment used in the degreasing step. FIG. 4 is a perspective view showing the degreasing jig in a state where the laminated body is arranged. FIG. 5 is a diagram showing oxygen dissociation curves of copper and lead. FIG. 6 is a partial perspective view showing a modification of the degreasing jig. FIG. 7 is a perspective view showing a configuration example of the degreasing jig of the second embodiment used in the degreasing step. FIG. 8 is a perspective view showing the degreasing jig in a state where the laminated body is arranged. FIG. 9 is an enlarged front view showing the support state of the laminated body. FIG. 10 is a plan view showing a conventional example. FIG. 11 is a front view of FIG. FIG. 12 is a front view showing an improved example of the conventional example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out a degreasing method according to the present invention and a degreasing jig used therein will be described with reference to the drawings. In each embodiment, an example of a degreasing method applied to a degreasing process in the method of manufacturing a multilayer ceramic element will be described, but it goes without saying that the present invention is not limited to this.

(Embodiment 1)
FIG. 1 is a schematic perspective view showing an example of a multilayer ceramic element (here, a multilayer piezoelectric element) that is a target of the manufacturing method of the present invention, and FIG. 2 is a diagram showing a laminated state of the piezoelectric layer and the internal electrode layer. It is a vertical side view which shows an example. As shown in FIG. 1, the multilayer piezoelectric element 1 includes a multilayer body 4 in which an internal electrode layer 3 is inserted between a plurality of ceramic layers (piezoelectric layer 2). The multilayer body 4 serves as an active portion. Contributes to displacement. Although the thickness per layer of the piezoelectric layer 2 can be set arbitrarily, it is usually set to about 1 μm to 100 μm, for example. On both sides of the laminate 4, there are inactive piezoelectric layer regions 5 in which the internal electrode layer 3 is not formed as inactive regions. In some cases, the thickness of the piezoelectric layer in the inactive piezoelectric layer region 5 is set to be larger than the thickness of the piezoelectric layer 2 between the internal electrode layers 3.

  As shown in FIG. 2, the internal electrode layers 3 are alternately extended in opposite directions, and terminal electrodes (not shown) are electrically connected to the internal electrode layers 3 at the ends in the respective extension directions. .) Is provided. The terminal electrode may be formed, for example, by sputtering a metal such as Au, or may be formed by baking an electrode paste. The thickness of the terminal electrode is appropriately set depending on the application, the size of the laminated piezoelectric element 1 and the like, but is usually about 10 to 50 μm.

  In the laminated piezoelectric element 1, the internal electrode layer 3 has a function as an electrode for applying a voltage to each piezoelectric layer 2 and is made of a conductive material. In this case, a noble metal such as Ag, Au, Pt, or Pd can be used as the conductive material. However, in the first embodiment, it is preferable to use a base metal such as Cu for cost reduction. When Cu is used as the conductive material, the internal electrode layer 3 is formed by applying and baking a Cu paste.

On the other hand, a piezoelectric ceramic composition is used for the piezoelectric layer 2, and the piezoelectric ceramic composition to be used is mainly composed of a composite oxide having Pb, Ti, and Zr as constituent elements, for example. Here, the composite oxide includes, for example, lead zirconate titanate (PZT), lead titanate (PbTiO ₃ ), lead zirconate (PbZrO ₃ ), and zinc niobate [Pb (Zn _1/3 Nb _2/3 ) O ₃ ], or a composite oxide in which a part of Pb is substituted with Sr, Ba, Ca, etc. in a ternary composite oxide. it can.

  Such a laminated piezoelectric element 1 includes a laminating step in which a ceramic precursor (piezoelectric layer 2) or internal electrode layer 3 after firing is alternately laminated with a ceramic precursor layer and an internal electrode precursor layer to form a laminate. It is produced by a degreasing process for degreasing the laminate as a degreased body and a firing step for firing the degreased laminate. Hereinafter, a method for manufacturing the multilayer piezoelectric element 1 will be described.

In order to produce the laminated piezoelectric element 1, first, a lamination process is performed. In this lamination process, the raw material of the piezoelectric layer 2 is prepared, weighed according to the target composition, mixed, calcined, and pulverized to obtain a ceramic precursor powder. The raw material for the piezoelectric layer 2 includes oxides, carbonates, oxalates, hydroxides, and the like of elements constituting the piezoelectric layer 2. For example, the piezoelectric layer 2 is lead zirconate titanate. In this case, lead oxide (PbO), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO ₂ ) are used as raw materials. Next, a binder or the like is added to the obtained ceramic precursor powder to form a ceramic raw material mixture, and the ceramic raw material mixture is formed into a sheet shape to form a ceramic precursor layer.

  Similarly, a base metal that is a raw material of the internal electrode layer 3, such as metallic copper, is prepared, and a binder or the like is added to form an internal electrode raw material mixture. As a raw material for the internal electrode layer 3, metallic copper may be used alone or in combination with other materials. In this case, examples of the other material include a copper oxide or an organic copper compound which becomes metal copper after firing, and a metal other than metal copper, a metal oxide, an organic metal compound, or the like. Moreover, you may add additives, such as a dispersing agent, a plasticizer, a dielectric material, an insulator material, to an internal electrode raw material mixture as needed.

  The internal electrode precursor layer is formed by, for example, screen printing the internal electrode raw material mixture on the ceramic precursor layer. As described above, a plurality of ceramic precursor layers on which the internal electrode precursor layers are formed are stacked to obtain a stacked body in which the ceramic precursor layers and the internal electrode precursor layers are alternately stacked. The laminated body to be the degreased body is a comparatively large shape formed in a rectangular parallelepiped shape, for example, a 9 × 9 × 40 mm size as an example of a long columnar shape having a uniform thickness.

  After such a lamination process, a degreasing process is performed with respect to the obtained laminated body by a degreasing process. The degreasing step is a step of decomposing and removing the ceramic precursor layers and the binders contained in the internal electrode precursor layers constituting the laminate by heating. FIG. 3 is a perspective view illustrating a configuration example of the degreasing jig according to the first embodiment used in the degreasing process, and FIG. 4 is a perspective view illustrating the degreasing jig in a state where the laminate is disposed. .

  The degreasing jig 10 according to the first embodiment is configured to be capable of supporting a plurality of, for example, 121 laminates 6 having the same shape in a vertically placed state, and includes a first support member 11 and a second support member. 12 and spacers 13 and 14.

  The 1st support member 11 is a flat plate-shaped thing formed in the square shape as a whole, and has the mounting surface 11a in which the end surface 6a by the side of the bottom face of each laminated body 6 mounted vertically is mounted. . The mounting surface 11a forms a plurality of, for example, 121 receiving portions 11c having a cross shape smaller than the size (area) of the end surface 6a by a plurality of openings 11b arranged two-dimensionally in a grid pattern. It is comprised by doing. That is, the mounting surface 11a supports the end surface 6a of each stacked body 6 placed vertically on the receiving portion 11c in a state of being in partial contact with each other, and the upper and lower surfaces orthogonal to the end surface 6a through the surrounding opening 11b. It has gas permeability that penetrates in the direction (longitudinal direction of the laminate 6). The spacer 13 is configured to support the first support member 11 at a predetermined height position from the installation surface at the installation position of the degreasing jig 10 so as to ensure gas permeability through the opening 11b. belongs to.

  Similar to the first support member 11, the second support member 12 is a flat plate having a generally square shape. By interposing spacers 14 at the four corners, the second support member 12 is located above the first support member 11. Are disposed at predetermined height positions. The second support member 12 has a plurality of, for example, supports for supporting each stacked body 6 in a state where the stacked bodies 6 are vertically placed on the placement surface 11a (receiving portion 11c) (the longitudinal direction of the stacked body 6 is a vertical direction). 121 openings 12a are provided. These openings 12a are formed in the second support member 12 in a two-dimensional and orderly arrangement, so that the longitudinal directions are parallel to each other in a state in which each laminate 6 is vertically placed on the receiving portion 11c. In order to support by being evenly arranged at equal intervals in the horizontal plane. Moreover, the opening 12a is formed with an opening ratio that does not cause the arrangement of the stacked bodies 6 supported by the second support member 12 to be too honey and the strength of the second support member 12 does not decrease.

  Furthermore, each opening 12a in the second support member 12 is formed slightly larger by a predetermined dimension than the size of the horizontal section of the stacked body 6 placed vertically, thereby providing gas permeability and the stacked body 6. It can be inserted and removed in the vertical direction (longitudinal direction). The gap is set to a predetermined size because if the gap with respect to the laminated body 6 is too large, the effect of preventing the falling of the laminated body 6 is reduced, and if the gap is too small, the insertion / removal workability of the laminated body 6 with respect to the opening 12a is lowered. This is because the gas permeability of the degreasing gas is reduced when the laminate 6 is degreased. Further, the arrangement position of the second support member 12 is set by the spacer 14 so as to be on the upper side from the center in the longitudinal direction of the stacked body 6 placed vertically on the receiving portion 11c. When the arrangement position of the second support member 12 is below the center in the longitudinal direction of the laminate 6, the support in the vertically placed state of the laminate 6 tends to become unstable, whereas it is set to the upper side. This is because it becomes easy to support the laminate 6 straightly. Moreover, since the handleability of the laminated body 6 will be impaired if the arrangement | positioning position of the 2nd support member 12 is too much on the upper end side of the laminated body 6, it is set as the position where the upper end side of the laminated body 6 protrudes on the 2nd support member 12. It is preferable.

  Further, the first support member 11 and the second support member 12 constituting the degreasing jig 10 are made of a material having high heat resistance and high thermal conductivity, including the spacers 13 and 14. Specifically, a metal such as Inconel (trade name) having high thermal conductivity and high heat resistance, or ceramics is used.

  When degreasing the laminated body 6, first, a degreasing jig 10 as shown in FIG. 3 and a plurality of, for example, 121 laminated bodies 6 are prepared, and each laminated body 6 is vertically placed on the degreasing jig 10. Place with. That is, as shown in FIG. 4, each laminated body 6 is horizontally leveled by the degreasing jig 10 so that the adjacent spaces 7 for providing gas permeability are parallel to each other in the longitudinal direction. It is evenly arranged and supported in a two-dimensional plane of directions. The degreasing jig 10 on which the plurality of laminated bodies 6 are arranged in this manner is inserted and set in a degreasing tubular furnace.

  Next, in FIG. 4 with respect to each adjacent space 7 so as to penetrate from one end (upper end) side to the other end (lower end) side along the longitudinal direction of each laminate 6 supported by the degreasing jig 10. Degreasing each laminated body 6 is performed by flowing a degreasing gas as indicated by an arrow. This degreasing step is preferably performed in a reducing atmosphere in order to suppress oxidation of the metal contained as the raw material of the internal electrode layer 3. When performing a degreasing treatment in a reducing atmosphere, cracks and internal electrode elution are a major problem because decomposition of the binder or the like is difficult to occur, but by using the degreasing jig 10 of the first embodiment, these The advantage of performing the degreasing treatment in a reducing atmosphere while solving the problem can be obtained.

Specifically, the reducing atmosphere means that the oxide that the ceramic precursor layer contains as a raw material for the ceramic layer (piezoelectric layer 2) and the metal that the internal electrode precursor layer contains as a raw material for the internal electrode layer 3 can coexist. It is an atmospheric gas having an oxygen partial pressure. For example, when the piezoelectric layer 2 contains lead oxide (PbO) as an oxide and the internal electrode layer 3 contains copper (Cu) as a metal, degreasing is performed in an atmospheric gas having an oxygen partial pressure in which Cu and PbO can coexist. It is preferable to perform a process. As shown in the oxygen dissociation curve of copper and lead in FIG. 5, the atmospheric gas having an oxygen partial pressure in which the metal and the oxide can coexist is not oxidized by the metal (for example, Cu) and the oxide (for example, , PbO) refers to an atmospheric gas having an oxygen partial pressure that is not reduced. It is also preferable to perform the degreasing step in an oxygen partial pressure atmosphere in which an inert gas such as nitrogen (N ₂ ) or argon (Ar), water vapor, and if necessary, an atmosphere gas containing hydrogen is introduced into the furnace. It is.

  In the degreasing step, the temperature during the degreasing treatment is preferably 600 ° C. or less. This is because if the degreasing temperature exceeds 600 ° C., the lead-based ceramic material starts to sinter, so that the densification may occur and the ventilation holes may be blocked, and decomposition and volatilization of the binder may be hindered.

  After the degreasing step, in the firing step, the degreasing jig 10 in which a plurality of degreased laminates 6 are arranged is placed in a mortar and used for firing, and inserted into a tubular furnace. The laminated piezoelectric element 1 is obtained by setting and firing the laminated body 6. The firing temperature is set to be higher than the degreasing temperature, for example, 900 ° C. to 1000 ° C. The firing step is also preferably performed in a reducing atmosphere. As in the case of the degreasing step, the reducing atmosphere is an oxide that the ceramic precursor layer includes as a raw material for the ceramic layer (piezoelectric layer 2), a metal that the internal electrode precursor layer includes as a raw material for the internal electrode layer 3, and Refers to an atmospheric gas having an oxygen partial pressure that can coexist.

  Further, in the firing step, when the temperature in the furnace exceeds 100 ° C., the firing atmosphere may be controlled to be a reducing atmosphere by introducing a predetermined atmospheric gas whose oxygen partial pressure is adjusted. The predetermined atmospheric gas contains, for example, an inert gas (such as nitrogen or Ar), hydrogen, and water vapor. By introducing the atmospheric gas when the temperature in the furnace exceeds 100 ° C. in the firing step, oxidation and elution of the internal electrode layer 3 can be suppressed without complicated control.

  According to the degreasing method as described above, the plurality of laminated bodies 6 are partially supported by the degreasing jig 10 so as to reduce the contact area, and the flow path resistance along each longitudinal direction. Since the degreasing gas flows through the adjacent space 7 so that the distribution is uniform and penetrates from one end side to the other end side, even in the reducing atmosphere, the degreasing gas spreads uniformly and uniformly with respect to each laminate 6, and the productivity It is possible to satisfactorily perform degreasing with respect to a large number of laminated bodies 6 that can ensure the above. Therefore, since a binder etc. can fully be removed from the laminated body 6, generation | occurrence | production of malfunctions, such as generation | occurrence | production of a crack and a metal used for an internal electrode layer in a subsequent baking process, can be suppressed reliably. .

  In addition, about the receiving part 11c of the 1st support member 11 which comprises the jig | tool 10 for degreasing, although it formed in flat shape by forming the opening 11b in the plate-shaped 1st support member 11, in such a shape, Not exclusively. For example, the mounting surface 11a is formed in a triangular or linear cross section so that there is substantially no flat portion, or by using a wire-like member, the end surface 6a of the laminate 6 is supported so as to be in line contact. May be. According to this, the contact part of the laminated body 6 and the 1st supporting member 11 can be reduced as much as possible, and the degreasing property in a reducing atmosphere can be improved further.

  Further, in place of the first support member 11, as shown in FIG. 6, a first support member 21 having a mounting surface 21a formed in a bottom-up network structure may be used. The net-like first support member 21 is formed in a grill net shape using a plurality of wire-like metal wires, and supports the end face 6a of the rectangular parallelepiped laminated body 6. In this case, the aperture ratio in the mounting surface 21 a is set to about 50% with respect to the mounting area S of the end surface 6 a of the stacked body 6. This reduces the contact area of the mounting surface 21a to the end surface 6a of the stacked body 6 as much as possible and secures gas permeability while ensuring that the stacked body 6 is in a reticulated space regardless of the position on the mounting surface 21a. This is to avoid falling into the inside. Such a first support member 21 is formed with a strength capable of maintaining the flatness of the mounting surface 21a, and is placed at a predetermined height position from the installation surface by a spacer 13 (not shown in FIG. 6). By supporting in the raised state, the gas permeability that penetrates through the mesh portion is ensured.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. FIG. 7 is a perspective view showing a configuration example of a degreasing jig according to the second embodiment used in the degreasing process, and FIG. 8 is a perspective view showing the degreasing jig in a state where a laminated body is arranged. FIG. 9 is an enlarged front view showing a support state of the laminated body. The degreasing jig 30 of the second embodiment is configured to be able to support a plurality of, for example, 121 laminates 6 having the same shape in a horizontally placed state, and includes a first support member 31 and a second support member. 32, a spacer 34, and a leg member 35. The leg member 35 is for preventing the degreasing jig 30 that supports the laminated body 6 in the horizontal position from falling down.

  The first support member 31 has a flat plate shape that is formed in a square shape as a whole. The first support member 31 has a rectangular shape corresponding to a plurality of, for example, 121 pieces, for partially supporting a part of the side surface 6b on one end side in the longitudinal direction of each stacked body 6 as a bottom surface. It has the 1st opening 31a. These first openings 31a are formed in the first support member 31 in a two-dimensional and orderly arrayed manner.

  The second support member 32 is a flat plate having a generally square shape, and is basically formed in the same shape as the first support member 31 and separated by a predetermined distance by a spacer 34. . Therefore, a plurality of, for example, 121 pieces of the second support members 32 are provided for supporting by partially contacting a part of the side surface 6b on the other end side in the longitudinal direction of each laminated body 6 placed horizontally as a bottom surface. A rectangular second opening 32a is provided. These second openings 32a are formed in the second support member 32 in a two-dimensional and orderly arrayed manner.

  In addition, the first and second openings 31a and 32a are arranged so that the arrangement of the laminated body 6 supported by the first and second support members 31 and 32 is not too honey and the first and second support members. 31 and 32 are formed with an aperture ratio that does not lower the strength. Furthermore, each 1st, 2nd opening 31a, 32a in the 1st, 2nd support members 31 and 32 is slightly larger by the predetermined dimension than the magnitude | size of the cross section of the laminated body 6 placed horizontally, The laminated body 6 can be inserted and removed in the front-rear direction (longitudinal direction) with gas permeability. The gap is set to a predetermined dimension. If the gap with respect to the laminate 6 is too large, it becomes difficult to arrange the laminate 6 uniformly. If the gap is too small, the laminate 6 with respect to the first and second openings 31a and 32a. This is because the gas permeability of the degreasing gas is lowered when the laminated body 6 is degreased.

  Further, in these first and second openings 31a and 32a, as shown in the enlarged view of FIG. 9, a plurality of protrusions for supporting with a reduced contact portion with respect to the side surface 6b serving as the bottom surface of the laminate 6 31b and 32b are formed (not shown in FIGS. 7 and 8). In the second embodiment, a plurality of protrusions 31b and 32b are formed uniformly on all four sides of the inner wall in the first and second openings 31a and 32a, and the degreasing gas flows as evenly as possible around the laminate 6. However, the plurality of protrusions 31b and 32b may be formed only on the bottom portion that receives the side surface 6b serving as the bottom surface, and the protrusions on the left and right sides and the upper side may be omitted. Moreover, although the example of the shape of the protrusions 31b and 32b shows a triangular shape, any shape may be used as long as it does not have a flat portion at the upper end.

  Therefore, the degreasing jig 30 according to the second embodiment has the first and second openings 31a and 32a to uniformly arrange the stacked bodies 6 in a vertical plane in which the longitudinal directions are parallel to each other and perpendicular to the longitudinal direction. It is comprised so that it may be supported. Further, the first support member 31 and the second support member 32 constituting the degreasing jig 30 are made of a material having high heat resistance and high thermal conductivity, including the spacer 34 and the leg member 35. Specifically, a metal such as Inconel (trade name) having high thermal conductivity and high heat resistance, or ceramics is used.

  When degreasing the laminated body 6, first, a degreasing jig 30 and a plurality of, for example, 121 laminated bodies 6 as shown in FIG. 7 are prepared, and each laminated body 6 is placed in the degreasing jig 30 horizontally. Place with. That is, as shown in FIG. 8 and FIG. 9, the degreasing jig is configured so that each laminated body 6 has a parallel in the longitudinal direction and the adjacent spaces 7 for providing gas permeability are substantially uniform at equal intervals. 30 are arranged and supported evenly in a two-dimensional plane in the vertical direction. The degreasing jig 30 on which the plurality of laminated bodies 6 are arranged in this way is inserted and set in a degreasing tubular furnace.

  Next, an arrow in FIG. 8 indicates the adjacent space 7 so as to penetrate from the one end (front end) side to the other end (rear end) side along the longitudinal direction of each laminated body 6 supported by the degreasing jig 30. The degreasing gas is allowed to flow as shown in FIG. This degreasing step is preferably performed in a reducing atmosphere in order to suppress oxidation of the metal contained as the raw material of the internal electrode layer 3. When the degreasing treatment is performed in a reducing atmosphere, cracks and internal electrode elution are serious problems because decomposition of the binder or the like is difficult to occur. However, these problems can be solved by using the degreasing jig 30 of the second embodiment. The advantage of performing the degreasing treatment in a reducing atmosphere while eliminating the above can be obtained. The reducing atmosphere, the temperature during the degreasing process, and the like are the same as in the first embodiment.

  After the degreasing step, in the firing step, the degreasing jig 30 in which a plurality of degreased laminates 6 are arranged is placed in a mortar and used for firing, and inserted into a tubular furnace. The laminated piezoelectric element 1 is obtained by setting and firing the laminated body 6. When firing, another firing jig may be used instead of the degreasing jig 30.

  According to the degreasing method as described above, the plurality of laminated bodies 6 are partially supported by the degreasing jig 30 so as to reduce the contact area, and the flow path resistance along each longitudinal direction. Since the degreasing gas flows through the adjacent space 7 so that the distribution is uniform and penetrates from one end side to the other end side, even in the reducing atmosphere, the degreasing gas spreads uniformly and uniformly with respect to each laminate 6, and the productivity It is possible to satisfactorily perform degreasing with respect to a large number of laminated bodies 6 that can ensure the above. Therefore, since a binder etc. can fully be removed from the laminated body 6, generation | occurrence | production of malfunctions, such as generation | occurrence | production of a crack and a metal used for an internal electrode layer in a subsequent baking process, can be suppressed reliably. .

Examples to which the present invention is applied will be described below.
(Lamination process: Production of laminate)
PbO, ZrO ₂ , TiO ₂ , SrCO ₃ , ZnO, Nb ₂ O ₅ , Ta ₂ O ₅ raw material powders are weighed in predetermined amounts, wet mixed by a ball mill for 16 hours, dried, and then 700 to 900 in an air atmosphere. Calcination was carried out at 2 ° C. for 2 hours. Thereafter, the powder was wet pulverized by a ball mill for 16 hours and dried to obtain a ceramic powder. This ceramic powder was mixed with an acrylic binder, a solvent and the like to form a slurry, and a green sheet was formed by a doctor blade method. Also, after mixing with copper powder and ethyl cellulose binder, solvent, etc. to make a paste and printing on a green sheet to a thickness of less than 1 to 2 μm, 300 layers of the sheet are laminated to 80 ° C., 1 ton / cm. ^The laminate 6 was obtained by thermocompression bonding with ² and cut into 9 × 9 mm.

(Degreasing process)
The 121 laminates 6 produced in this way are placed in a vertically placed state on a degreasing jig (vertical placing jig) 10 as described in Embodiment 1, inserted into a tubular furnace, and at 550 ° C. Degreasing was carried out by holding for 32 hours. At this time, a mixed gas containing H ₂ O in N ₂ and H ₂ was introduced from above so that the oxygen partial pressure at which the metallic copper and lead oxide can coexist at the degreasing temperature was obtained.

  For comparison, 121 laminates 6 are placed on a setter having a center line average surface roughness as shown in Patent Document 1, and the height is as shown in FIG. Degreasing was carried out in the same manner by stacking in two directions via spacers in the direction.

  After each degreasing, 20 laminates 6 were extracted, and the amount of residual carbon after the degreasing was analyzed using a combustion / infrared absorption method in an oxygen stream.

(Baking process)
The remaining 101 laminated bodies 6 were placed in a mortar as they were together with the degreasing jig 10 and a two-stage setter, inserted into a tubular furnace, and fired by holding at 950 ° C. for 8 hours. At this time, a mixed gas containing H ₂ O in N ₂ and H ₂ was introduced from above so that the oxygen partial pressure at which the metal copper and lead oxide can coexist at the firing temperature was obtained. Further, the inside of the mortar was not completely sealed, and a gap was provided in the lid with a spacer having a thickness of 0.5 mm so that gas replacement could be performed. And the external appearance of the laminated body 6 was observed visually after each baking, and the elution and the crack of Cu were confirmed. These analysis and observation results are shown in Table 1.

  When the appearance of the laminate 6 after degreasing was observed, when a two-stage setter was used, only the setter mounting surface was black in the upper laminate, whereas the entire laminate was blackened in the lower laminate In the laminated body 6 of this example using the degreasing jig (vertical placing jig) 10, black was not seen as a whole. In addition, the residual carbon amount was 320 ppm for the upper laminate when the two-stage setter was used, and 850 ppm for the lower laminate, whereas the degreasing jig (vertical jig) 10 In the laminated body 6 of the present example using this, it is 250 ppm, which is a target value of 300 ppm or less. Moreover, according to the appearance observation after firing, when a two-stage setter was used, Cu was eluted uniformly for all the laminated bodies regardless of the upper and lower stages, whereas the degreasing jig ( In the laminated body 6 of this example using the vertically placed jig 10, no appearance defect was observed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first and second embodiments, the rectangular parallelepiped laminated body 6 is a degreased body to be degreased, but is not limited to such a shape. As the degreased body, what is essential is that it is formed in a long column shape with a uniform thickness, and may be, for example, a cylindrical shape.

  In the first and second embodiments, the laminate 6 is partially supported by the degreasing jigs 10, 20, and 30 at two locations. You may make it support. That is, a plurality of second support members 12 and 32 may be provided.

6 Laminated body 6a End surface 6b Side surface 7 Adjacent space 10 Degreasing jig 11 First support member 11a Placement surface 12 Second support member 12a Opening 21 First support member 21a Placement surface 31 First support member 31a First opening 32 Second support member 32a Second opening

Claims (5)

A plurality of degreased bodies of the same shape formed in a rectangular column shape having a uniform thickness and a uniform thickness are evenly arranged in a two-dimensional plane whose longitudinal directions are parallel to each other and perpendicular to the longitudinal direction, and degreasing gas The first support that partially supports at least two locations in the longitudinal direction so that each of the degreased bodies has gas permeability that penetrates in the longitudinal direction and is detachable in the longitudinal direction. Using a degreasing jig comprising a member and a second support member, and a spacer,
Said first support member is vertically and is the end surface of each of the degreased body is to have a gas permeability which penetrates in a direction perpendicular to the end face while supporting partially contacts touch state placed face Have
The second support member is disposed above the first support member, and in a state where the degreased bodies are vertically placed on the placement surface, the longitudinal directions are parallel to each other and are evenly arranged in a horizontal plane. And has a plurality of openings that are formed in a lattice shape so as to support and each of the degreased bodies can be inserted and removed,
The spacer is disposed on one surface side of the first support member and the second support member, the first support member is provided at a predetermined height position from the installation surface, and the second support member is disposed on the first support member. It is provided to be at a predetermined height position above the support member,
A plurality of said object to be degreased body, a longitudinal direction is the evenly in a two-dimensional plane orthogonal to the longitudinal direction of the degreased body so that respective adjacent spaces for imparting parallel gas permeability from each other is uniform A support process for arranging and supporting;
Degreasing the degreased body by flowing a degreasing gas to the adjacent space so as to penetrate from one end side to the other end side along the longitudinal direction of each degreased body supported by the degreasing jig. A degreasing process to be performed;
A degreasing method comprising:   The degreasing method according to claim 1, wherein the step of degreasing the degreased body is performed in a reducing atmosphere. The object to be degreased body, degreasing method according to claim 1 or 2, characterized in that it comprises a lead-based piezoelectric material. The object to be degreased body, degreasing method according to any one of claims 1 to 3, characterized in that a laminated piezoelectric element including an internal electrode of copper. Each opening of the said 2nd supporting member is formed larger by the predetermined dimension than the magnitude | size of the horizontal cross section of the said to-be-degreased body placed vertically, The Claim 1 characterized by the above-mentioned. Degreasing method.

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