JP2007088448A - Film and fabrication process of inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a film while avoiding the occurrence of a defect in the film or breakage of the film during annealing, and to provide ceramic particles suitable for producing such a film. <P>SOLUTION: After material particles M are prepared and before depositing a film, the material particles M are subjected to heat treatment. Consequently, moisture and additives causing gasification in the subsequent anneal process are evaporated beforehand and removed and thereby defect and breakage of a piezoelectric film 3 can be avoided in the anneal process. Consequently, an actuator plate 1 for an inkjet head 10 having good piezoelectric characteristics can be provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film and a method for manufacturing an inkjet head.

For example, there is a method called an aerosol deposition method (AD method) as a manufacturing method of a piezoelectric actuator used for an ink jet head or the like. In Patent Document 1 (Japanese Patent Laid-Open No. 2001-152360), piezoelectric material fine particles such as lead zirconate titanate (PZT) dispersed in a gas (aerosol) are jetted toward the substrate surface, and the fine particles are ejected. A method of forming a piezoelectric film by colliding and depositing on a substrate is disclosed.
JP 2001-152360 A

  Here, the piezoelectric film formed by the AD method as described above needs to be annealed in order to obtain the piezoelectric characteristics necessary for sufficiently bending the substrate.

  However, according to experiments conducted by the present inventors, if annealing is performed at a high temperature in order to obtain sufficient piezoelectric characteristics, defects may occur in the film, and in extreme cases, the film may be destroyed. It was. If such a situation occurs, it will lead to a decrease in insulation and, in turn, a decrease in piezoelectric characteristics, and so improvement is necessary.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a film manufacturing method capable of avoiding the generation and destruction of a film defect during annealing, and an ink jet head manufacturing method using the film. Is to provide.

  The inventors of the present invention have intensively studied to develop a film manufacturing method capable of avoiding film breakage during annealing, and have found the following knowledge.

  The components that cause gasification and cause defects in the film in the annealing process are considered to be moisture mixed in the process of preparing ceramic particles, additives to be added, or decomposition products thereof.

  That is, in order to prepare the ceramic particles used in the AD method, usually, the raw material is pulverized and classified to obtain a fine powder having an appropriate particle size. Moreover, if it is a ceramic material synthesize | combined from multiple types of raw material, it will pass through the procedure of grind | pulverizing, after mixing raw material powder, pre-sintering. At this time, if it is wet mixing, water may be mixed in the solvent used. In addition, a sintering aid for assisting the sintering may be added to the raw material powder. Furthermore, a dispersing agent or a coating agent for preventing aggregation of particles may be added after pulverization. In addition, when the raw material powder itself is easy to form a hydrate, it is considered that it contains water and volatile components at the time of the raw material ore before being pulverized. Of these moisture and additives, components that decompose and vaporize below the annealing temperature cause film defects. In addition, about water | moisture content, it mixed by physical adsorption (physical adsorption water) etc. which adsorb | suck to the pore of the powder surface, and it mixed by chemical adsorption (chemical adsorption, such as being contained as crystal water at the time of manufacture). Water).

  Therefore, it is possible to avoid the generation and destruction of film defects in the annealing process by preheating the ceramic particles prior to film formation and preliminarily vaporizing and removing the contained moisture and additives. It can be done. The present invention has been made based on such novel findings.

  That is, according to the first aspect of the present invention, a film is formed by applying a heat treatment step of heat-treating ceramic particles and spraying an aerosol containing the ceramic particles after the heat treatment step onto a substrate to attach the ceramic powder. There is provided a method of manufacturing a film, including a film forming process for forming a film and an annealing process for annealing the film.

  According to the second aspect of the present invention, an ink flow path forming body provided with a plurality of pressure chambers communicating with an ink discharge nozzle for discharging ink and having an opening opening on one side, and the ink A method of manufacturing an ink jet head comprising: a diaphragm provided on one surface side of a flow path forming body so as to close the opening; and a piezoelectric actuator comprising a piezoelectric film laminated on the diaphragm, Forming a piezoelectric film by heat-treating the piezoelectric material particles and spraying the aerosol containing the piezoelectric material particles after the heat-treatment step onto the diaphragm and attaching the piezoelectric material particles to the diaphragm A piezoelectric film forming step, an annealing process step for annealing the piezoelectric film, and an electrode layer forming step for forming an electrode layer on the piezoelectric film. Granulation method is provided.

  The heating temperature in the heat treatment step may be appropriately set in consideration of the type of component to be removed. For example, moisture (physically adsorbed water) adhering in the pores on the surface of the ceramic particles can be removed at about 150 ° C. or higher. Moreover, the gasification component contained in additives, such as a dispersing agent and a sintering auxiliary agent normally used for preparation of ceramic particle | grains, can be removed at about 200-400 degreeC or more. In particular, when the material constituting the ceramic particles contains chemically adsorbed moisture (chemically adsorbed water), it is preferable to heat at a temperature at which the moisture is released (about 600 ° C.) or higher.

  Further, if the heating temperature is set to be equal to or higher than the annealing temperature in the annealing step, all components that are gasified at the annealing temperature are removed in advance, which is extremely preferable. Furthermore, the heating time may be of a length that can remove components easily contained in the ceramic particles that are easily gasified, and is preferably 30 minutes or longer. Furthermore, in order to prevent particles from aggregating due to static electricity or intermolecular force acting on the powder surface due to heating, it is preferable to perform a dry pulverization step.

  In the film of the present invention and the method for manufacturing an inkjet head, the heating temperature in the heat treatment step may be 450 ° C. to 850 ° C. In this case, the volume resistivity is increased and good insulation is ensured.

  The ceramic particles of the present invention are not particularly limited as long as they are usually used for forming a film, and examples thereof include α-alumina, zirconia, and partially stabilized zirconia. In addition, the production method of the present invention can be preferably used for forming a piezoelectric film in a piezoelectric actuator used in, for example, an inkjet head. In this case, as ceramic particles, lead zirconate titanate (PZT), Particles of a material having a perovskite structure that is usually used as a piezoelectric material, such as lead magnesium niobate (PMN), can be used.

  If the ceramic particles are particles made of a single material such as α-alumina, for example, the ceramic particles can be obtained by pulverizing the raw material followed by heat treatment. Moreover, in the case of ceramics synthesized from a plurality of types of raw materials such as PZT, target ceramic particles can be obtained by heat-treating the fine powder obtained by mixing and firing the raw material powder and then pulverizing it. it can.

  The ceramic particles of the present invention preferably have a weight reduction rate of 0.2% by weight or less when heated from room temperature to 900 ° C. by thermogravimetry, and the weight reduction rate when heated to 600 ° C. is 0. More preferably, it is 18% by weight or less. Here, the weight reduction due to heating can be considered to be gasification components such as moisture (physically adsorbed water, chemically adsorbed water) and additives contained in the ceramic particles. Thus, if the film is formed using ceramic particles with very little gasification component, that is, the weight loss due to heating, the gas generation during the annealing process can be made extremely small, and the destruction of the film can be prevented. Can do.

  Further, it is more preferable that the weight reduction rate when the temperature is raised to 180 ° C. is 0.15% by weight or less. The weight loss at this temperature is physically adsorbed water adhering to the particle surface and volatile components contained in additives such as dispersants, but by removing these from the particle surface in advance, It is possible to prevent the newly active surface having high activity caused by the collision and destruction of particles with the substrate during film formation from being contaminated with these components, and to improve the film forming property and the quality of the formed film.

  The ceramic particles of the present invention preferably have a specific surface area of 10 m2 / g or less. If the particles have such a small specific surface area, the amount of moisture that can adhere to the surface is small, so that the amount of gas generated during annealing can be reduced.

  In addition, since the ceramic particles have higher hardness and compressive fracture strength as the amount of crystal water is smaller, the hardness and compressive fracture strength can be used as an index of the content of crystal water. From such a viewpoint, the ceramic particles of the present invention have a hardness measured using a nanoindenter in a range of 50 Hv to 800 Hv in terms of Vickers hardness, and a compressive fracture strength in a range of 0.5 GPa to 8 GPa. It is preferable that. Since such ceramic particles contain a very small amount of crystal water, even if annealing is performed at a high temperature, the amount of gas generated can be kept to a minimum and the destruction of the film can be prevented.

  Furthermore, the crystallinity of the ceramic particles measured by the X-ray diffraction method can also be used as an index of the content of crystal water. From such a viewpoint, it is preferable that the ceramic particles of the present invention have a crystallinity of 80% or more by an X-ray diffraction method. Since such ceramic particles contain a very small amount of crystal water, even if annealing is performed at a high temperature, the amount of gas generated can be kept to a minimum and the destruction of the film can be prevented.

  According to the present invention, since the ceramic particles are heated after the ceramic particles are prepared and before film formation, moisture and additives that cause gasification are vaporized in advance in the subsequent annealing step. By removing it, it is possible to avoid film defects and destruction in the annealing process. This makes it possible to form a high quality film having excellent insulation properties. Further, by applying the manufacturing method of the present invention to the formation of a piezoelectric film in a piezoelectric actuator, it is possible to avoid a decrease in piezoelectric characteristics due to a defect or breakage of the piezoelectric film and to obtain a piezoelectric actuator having good piezoelectric characteristics. it can.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to FIGS. In the present embodiment, an example in which the present invention is applied to manufacture of a piezoelectric actuator for an inkjet head will be described.

  FIG. 1 shows an inkjet head 10 according to this embodiment. The inkjet head 10 includes a flow path unit 11 (ink flow path forming body) having a plurality of pressure chambers 16 in which ink 20 is accommodated, and an actuator joined on the flow path unit 11 so as to close the pressure chambers 16. Plate 1 (piezoelectric actuator).

  The flow path unit 11 has a flat plate shape as a whole, and the nozzle plate 12, the manifold plate 13, the flow path plate 14, and the pressure chamber plate 15 are sequentially stacked, and the plates 12, 13, 14, 15 are mutually connected. It is configured to be joined with an epoxy thermosetting adhesive.

  The nozzle plate 12 is formed of a polyimide-based synthetic resin material, and a plurality of ink discharge nozzles 19 for ejecting the ink 20 are formed in an array therein. The manifold plate 13 is formed of a metal material such as stainless steel, and a plurality of nozzle channels 18 connected to the ink discharge nozzles 19 are provided therein. The flow path plate 14 is also formed of a metal material such as stainless steel, and a plurality of pressure flow paths 17 communicating with the nozzle flow paths 18 are provided therein. The pressure chamber plate 15 is also made of a metal material such as stainless steel, and a plurality of pressure chambers 16 communicating with the pressure channel 17 are provided therein. The pressure chamber 16 is connected to an ink tank through a flow path plate 14, a manifold flow path (not shown) provided in the manifold plate 13, and a common ink chamber. In this way, a path is formed from the common ink chamber connected to the ink tank to the ink discharge nozzle 19 via the manifold channel, the pressure chamber 16, the pressure channel 17, and the nozzle channel 18.

  The actuator plate 1 stacked on the flow path unit 11 includes a diaphragm 2 that also serves as a lower electrode that constitutes a part of the wall surface of the pressure chamber 16, a piezoelectric film 3 formed on the diaphragm 2, The upper electrode 4 is provided on the piezoelectric film 3.

  The diaphragm 2 is formed in a rectangular shape with a metal material such as stainless steel (SUS430, SUS304), and an epoxy-based thermosetting adhesive applied to the upper surface of the flow path unit 11 or the diaphragm 2. And the flow path unit 11 are joined by heat diffusion so as to cover the entire upper surface of the flow path unit 11.

  A piezoelectric film 3 is provided on the surface of the diaphragm 2 opposite to the surface in contact with the flow path unit 11. The piezoelectric film 3 is made of a ferroelectric piezoelectric ceramic material such as lead zirconate titanate (PZT), and is laminated on the surface of the diaphragm 2 with a uniform thickness. The piezoelectric film 3 is formed by an aerosol deposition method, and is subjected to polarization processing so as to be polarized in the thickness direction.

  A plurality of upper electrodes 4 are provided on the surface of the piezoelectric film 3 opposite to the side in close contact with the diaphragm 2. The upper electrode 4 is provided in a region corresponding to the opening 16A of each pressure chamber 16, and is connected to the drive circuit IC.

  When printing, when a predetermined drive signal is issued from the drive circuit IC, the potential of the upper electrode 4 is set higher than that of the diaphragm 2 used as the lower electrode, and the polarization direction (thickness) of the piezoelectric film 3 is increased. Direction). Then, the piezoelectric film 3 expands in the thickness direction and contracts in the surface direction. Thereby, the piezoelectric film 3 and the diaphragm 2 (that is, the actuator plate 1) are locally deformed so as to protrude toward the pressure chamber 16 (unimorph deformation). For this reason, the volume of the pressure chamber 16 decreases, the pressure of the ink 20 increases, and the ink 20 is ejected from the ink discharge nozzle 19. Thereafter, when the upper electrode 4 is returned to the same potential as the lower electrode (vibrating plate 2), the piezoelectric film 3 and the vibrating plate 2 have the original shape, and the volume of the pressure chamber 16 returns to the original volume. 20 is sucked from the manifold flow path communicating with the ink tank. The diaphragm 2 is not limited to a metal material, and may be composed of a polyimide resin material or the like. In this case, a lower electrode is formed on the diaphragm 2 by screen printing or the like, a piezoelectric film 3 is formed on the lower electrode, and the piezoelectric film 3 is laminated on the diaphragm 2 via the lower electrode. Configure as follows.

  Next, a method for manufacturing the actuator plate 1 for the ink jet head 10 configured as described above will be described.

  First, as shown in FIG. 2A, the diaphragm 2 made of stainless steel is overlapped and joined to the upper surface of the pressure chamber plate 15 in the flow path unit 11, and each pressure chamber 16 is closed by the diaphragm 2. To do.

  Next, as shown in FIG. 2B, the piezoelectric film 3 is formed by an aerosol deposition method (AD method). FIG. 3 shows a schematic diagram of a film forming apparatus 30 for forming the piezoelectric film 3. The film forming apparatus 30 includes an aerosol generator 31 for forming an aerosol Z by dispersing material particles M (ceramic particles) in a carrier gas, and a film for discharging the aerosol Z from an injection nozzle 37 and attaching it to a substrate. A chamber 35 is provided.

  The aerosol generator 31 includes an aerosol chamber 32 in which the material particles M can be accommodated, and a vibration device 33 that is attached to the aerosol chamber 32 and vibrates the aerosol chamber 32. A gas cylinder B for introducing a carrier gas is connected to the aerosol chamber 32 via an introduction pipe 34. The distal end of the introduction tube 34 is located near the bottom surface in the aerosol chamber 32 and is buried in the material particles M. As the carrier gas, for example, an inert gas such as helium, argon, or nitrogen, air, oxygen, or the like can be used.

  The film forming chamber 35 is provided with a stage 36 for attaching a substrate on which a piezoelectric film is to be formed, and an injection nozzle 37 provided below the stage 36. The injection nozzle 37 is connected to the aerosol chamber 32 via an aerosol supply pipe 38, and the aerosol Z in the aerosol chamber 32 is supplied to the injection nozzle 37 through the aerosol supply pipe 38. In addition, a vacuum pump P is connected to the film forming chamber 35 via a powder recovery device 39 so that the inside thereof can be depressurized.

  A procedure for forming the piezoelectric film 3 using the film forming apparatus 30 will be described with reference to FIG. First, material particles M to be used are synthesized. As the material particles M, for example, particles of lead zirconate titanate (PZT), which are particles of a piezoelectric material, can be used. A method for synthesizing the material particles M is, for example, as follows.

  Lead oxide (PbO), titanium oxide (TiO2), and zirconium oxide (ZrO2) are used as raw materials, and these raw material powders are weighed based on the composition of the target material particles M. The weighed raw material powders are mixed while being pulverized with a ball mill using ethanol as a solvent (mixed powder generation step S1). The obtained mixed powder is temporarily fired in an air atmosphere to obtain a temporary sintered body of lead zirconate titanate (PZT) (sintered body generation step S2). The temporary sintered body can be pulverized while adding a sintering aid such as LiBiO2 to obtain a fine powder of PZT (powder generation step S3). This fine powder is used as material particles M.

  Next, the obtained material particles M are placed in an electric furnace set at a predetermined temperature, for example, 450 ° C. to 850 ° C., and heated for a predetermined time (heat treatment step S4). As a result, the water contained in the material particles M, the adhering water adhering to the surface of the material particles M, and the components contained in the additives such as the solvent, sintering aid and dispersant used during the synthesis are decomposed and vaporized in advance. To remove. Note that after the heat treatment, the material particles M may be pulverized (dry pulverization step) using a dry ball mill apparatus. This is performed by putting a ball made of high-purity zirconia or alumina and material particles M into a pot made of high-purity zirconia or alumina and rotating the pot. Although the heated material particles M may be aggregated due to static electricity or intermolecular force on the surface, the aggregated material particles M can be pulverized by performing a dry pulverization step. This pulverization step may be performed as necessary. Here, when many fine powders adhere around the material particles M after pulverization, the piezoelectric film 3 formed in the piezoelectric film forming process described later is formed in a state including these fine powders. At this time, when the fine powder collides with the diaphragm 2, it is difficult to receive the collision energy, and therefore, it is difficult to deform. Therefore, a void is generated around the fine powder contained in the piezoelectric film 3, and the piezoelectric characteristics of the piezoelectric film 3 are deteriorated. It can be a cause. Therefore, it is desirable to further perform a heat treatment at about 850 ° C. after the pulverization step to restore the piezoelectric characteristics.

  When the preparation of the material particles M and the heat treatment are completed, a film is formed (piezoelectric film forming step S5). First, the diaphragm 2 is set on the stage 36 of the film forming apparatus 30. Next, the material particles M subjected to the heat treatment are put into the aerosol chamber 32.

  And carrier gas is introduce | transduced from the gas cylinder B, and the material particle M is made to soar by the gas pressure. At the same time, the aerosol chamber 32 is vibrated by the vibration device 33, whereby the material particles M and the carrier gas are mixed to generate the aerosol Z. Then, by depressurizing the inside of the film forming chamber 35 with the vacuum pump P, the aerosol Z in the aerosol chamber 32 is accelerated from the injection nozzle 37 while being accelerated at a high speed by the differential pressure between the aerosol chamber 32 and the film forming chamber 35. Erupt. The material particles M contained in the ejected aerosol Z collide with the diaphragm 2 and deposit to form the piezoelectric film 3.

Subsequently, the formed piezoelectric film 3 is annealed (annealing step S6). Here, when film formation is performed using material particles M that are not subjected to heat treatment, annealing is performed at a high temperature (600 ° C. or higher, preferably 850 ° C. or higher) in order to obtain sufficient piezoelectric characteristics. Then, a part of the components contained in the piezoelectric film 3 is abruptly gasified and expands, which may cause defects in the film and destroy the film (FIG. 4A). However, in this embodiment, since the components that cause gasification contained in the material particles M are previously removed in the heat treatment step, defects and destruction of the film can be avoided, and as a result, the piezoelectric characteristics are excellent. A piezoelectric film 3 can be obtained (FIG. 4B).
Next, as shown in FIG. 2C, the upper electrode 4 and a plurality of lead portions (not shown) connected to the upper electrodes 4 are formed on the upper surface of the piezoelectric film 3 (electrode formation step S7). In order to form the upper electrode 4 and the lead portion, for example, a conductor film may be formed over the entire area of the piezoelectric film 3 and then formed into a predetermined pattern using a photolithography etching method. Alternatively, the piezoelectric film may be formed. A pattern may be formed directly on the upper surface of 3 by screen printing.

  Thereafter, an electric field stronger than that in the normal ink ejection operation is applied between the upper electrode 4 and the lower electrode (diaphragm 2) to polarize the piezoelectric film 3 between both electrodes in the thickness direction (polarization process step S8). . Thus, the actuator plate 1 is completed.

  As described above, according to the present embodiment, after the material particles M are synthesized, the material particles M are subjected to heat treatment before film formation. Thus, moisture and additives that cause gasification in the subsequent annealing process can be vaporized and removed in advance, and defects and destruction of the piezoelectric film 3 in the annealing process can be avoided. Thereby, it is possible to provide the actuator plate 1 for the ink jet head 10 having good piezoelectric characteristics.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Examples for investigating the effect of heat treatment on material particles on film]
<Example 1-1>
1. Formation of Film 1) Preparation of Ceramic Particles α-alumina (obtained from Showa Denko), which is a raw material, is pulverized by a ball mill and has an average particle size of about 1 μm and a particle size distribution as shown in FIG. A fine powder was obtained. The particle size distribution was measured using a dry particle size distribution measuring apparatus (HELOS & RODOS manufactured by Nippon Laser). This fine powder was put into a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.), and the temperature in the furnace was raised to 600 ° C. over 1 hour. After maintaining at 600 ° C. for 1 hour, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. FIG. 10 also shows the particle size distribution of α-alumina after the heat treatment.
2) Film formation A stainless steel (SUS430) plate was used as the substrate, and alumina powder prepared in 1) was used as the material particles. On the substrate, the nozzle opening 0.4 mm × 10 mm, the deposition chamber pressure 400 Pa, the aerosol chamber pressure 30000 Pa, the carrier gas type He, the gas flow rate is 6.0 liter / min, and the nozzle-substrate distance is 10-20 mm. Was sprayed to form an insulating film. The thickness of the film was approximately 3 μm as measured by a step using a surface roughness meter.
3) Annealing treatment Subsequently, the formed insulating film was annealed. The temperature of the muffle furnace was raised to 850 ° C., the substrate on which a film was formed was placed, and the substrate was held at 850 ° C. for 10 minutes. Thereafter, the substrate was taken out of the furnace and cooled to room temperature by natural cooling.
2. Test A 2 mm square upper electrode was formed on the insulating film by sputtering using an Au target. A voltage of 50 V was applied using the substrate as the lower electrode, and the volume resistivity was measured.

<Example 1-2>
Except that the thickness of the insulating film was 1 μm, α-alumina particles were prepared in the same manner as in Example 1-1, a film was formed, and the test was performed.

<Comparative Example 1-1>
Except that the alumina powder was not heat-treated, α-alumina particles were prepared in the same manner as in Example 1-1, an insulating film was formed, and the test was performed.

<Comparative Example 1-2>
Except that the alumina powder was not heat-treated, α-alumina particles were prepared in the same manner as in Example 1-2, an insulating film was formed, and the test was performed.

[Measurement result]
Table 1 shows the experimental results for Examples 1-1 and 1-2 and Comparative Examples 1-1 and 1-2.

From Table 1, it was found that when the alumina powder was not subjected to heat treatment, the volume resistivity was greatly reduced and the insulating property was lowered. This is considered to indicate that a component contained in the insulating film is gasified to cause a defect in the insulating film. On the other hand, it was found that when the alumina powder was heat-treated, the volume resistivity was large and the insulation was maintained.

Therefore, by subjecting the material particles before film formation to heat treatment in advance, it is possible to avoid the components contained in the insulating film from being gasified during the annealing process and causing the insulating film to be defective and broken. It can be said that it can be secured.
[Examples for examining the effect of heating temperature on material particles on film]
<Example 2-1>
The fine powder of α-alumina pulverized in the same manner as in Example 1-1 was placed in a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.) and heated to 150 ° C. over 90 minutes. After holding at 150 ° C. for 300 minutes, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated fine powder as material particles, an insulating film was formed and tested in the same manner as in Example 1-1. However, in the annealing treatment, the temperature of the muffle furnace was raised to 850 ° C., the substrate on which the film was formed was placed, and the substrate was held at 850 ° C. for 30 minutes.

<Example 2-2>
The α-alumina fine powder pulverized in the same manner as in Example 1-1 was placed in a muffle furnace and heated to 450 ° C. over 120 minutes. After maintaining at 450 ° C. for 60 minutes, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, an insulating film was formed and tested in the same manner as in Example 1-1. However, in the annealing treatment, the temperature of the muffle furnace was raised to 850 ° C., the substrate on which the film was formed was placed, and the substrate was held at 850 ° C. for 30 minutes.

<Example 2-3>
The fine powder of α-alumina pulverized in the same manner as in Example 1-1 was placed in a muffle furnace and heated to 600 ° C. over 120 minutes. After holding at 600 ° C. for 60 minutes, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, an insulating film was formed and tested in the same manner as in Example 2-2.

<Example 2-4>
The α-alumina fine powder pulverized in the same manner as in Example 1-1 was placed in a muffle furnace and heated to 850 ° C. over 120 minutes. After holding at 850 ° C. for 60 minutes, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, an insulating film was formed and tested in the same manner as in Example 2-2. However, the film thickness was 2 μm.

[Measurement result]
The measurement results for Examples 2-1 to 2-4 are shown in Table 2.

From Table 2, it was found that when the heating temperature of the alumina powder was 150 ° C. (Example 2-1), the volume resistivity was greatly reduced and the insulating property was lowered. This is because at this temperature, only the physically adsorbed water adhering to the surface of the alumina powder is removed, and the additive and crystal water are not removed. This is thought to be due to the occurrence of defects.

  It was found that when the heating temperature of the alumina powder was 450 ° C. (Example 2-2), the volume resistivity was slightly increased, and the insulation was maintained to some extent. At this temperature, in addition to physically adsorbed water, additives such as dispersants and sintering aids contained in the alumina powder are also decomposed and removed, so the degree of occurrence of defects during annealing is reduced. Conceivable. Furthermore, when the heating temperature of the alumina powder was 600 ° C. (Example 2-3), the volume resistivity was further increased, and good insulation was ensured. At this temperature, chemically adsorbed water such as crystal water contained in the alumina powder is also removed, so that it is considered that almost no film defects occurred during annealing.

  Further, when the heating temperature of the alumina powder was increased to 850 ° C. (Example 2-4), although high volume resistivity was shown, it was slightly lower than that at the heating temperature of 600 ° C. The reason is considered as follows. That is, when heated at a high temperature of about 800 ° C., moisture existing between the particles is completely eliminated, and the particles are directly fixed to become large particles. When aerosol containing these large particles is sprayed onto the substrate, the weight of the particles is so great that the particles adhering later damage the particles previously deposited on the substrate surface or collide with the substrate. In other words, a part of the collision energy is consumed because the particles aggregated with each other are separated, and the adhesion of the particles to the substrate is lowered. For this reason, the insulation of a film | membrane deteriorates.

As described above, not only moisture adhering to the surface of the particles, but also additives such as dispersants and sintering aids, and chemically adsorbed water such as crystallization water were better removed and defects were suppressed. It was found that a film having characteristics can be obtained.
[Examples and comparative examples for investigating the influence of piezoelectric material particles on the piezoelectric film due to heat treatment]
<Example 3-1>
1. Formation of Piezoelectric Film 1) Preparation of Piezoelectric Material Particles PZT (obtained from Sakai Chemical Industry), which is a raw material, is pulverized by a ball mill, and a fine powder of PZT having an average particle diameter of about 1 μm and a particle size distribution as shown in FIG. Got. The particle size distribution was measured using a dry particle size distribution measuring apparatus (HELOS & RODOS manufactured by Nippon Laser). This fine powder was put into a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.), and the temperature in the furnace was increased to 800 ° C. at 400 ° C./1 h. After holding at 800 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. The particle size distribution after heating at 800 ° C. and the particle size distribution when heated at other heating temperatures are also shown in FIG.
2) Film formation A stainless SUS430 plate is used as a substrate, an alumina insulating layer is formed thereon by AD method, and a Ti / Pt lower electrode layer is formed thereon by sputtering method, and then 1) is formed thereon. A piezoelectric film was formed by the AD method using the prepared PZT powder. The film forming conditions of the PZT piezoelectric film by the AD method are: nozzle opening 0.4 mm × 10 mm, film forming chamber pressure 300 Pa, aerosol chamber pressure 40000 Pa, carrier gas type He, gas flow rate 4.0 liter / min, nozzle-substrate Aerosol was sprayed at a distance of 10 to 30 mm to form an insulating film. The thickness of the film was approximately 8 μm as measured by a step using a surface roughness meter.
3) Annealing treatment Subsequently, an annealing treatment of the PZT piezoelectric film was performed. The temperature of the muffle furnace was raised to 850 ° C. at 400 ° C./1 h, the substrate on which the piezoelectric film was formed was put, and held at 850 ° C. for 30 minutes. Thereafter, the inside of the furnace was cooled by natural cooling.
2. Test Ten substrates on which PZT piezoelectric films were formed as described above were prepared, and the dielectric constant and dielectric loss were measured for ten substrates using an impedance analyzer HP-4194A manufactured by Hewlett-Packard.

<Comparative Example 3-1>
In the adjustment of the PZT piezoelectric material particles, a PZT piezoelectric film was formed and tested in the same manner as in Example 3-1, except that the PZT powder was not heat-treated.

[Measurement result]
Table 3 shows the relative dielectric constants measured in Example 3-1 and Comparative Example 3-1, and the average value of dielectric loss.

From Table 3, when the PZT powder was heat-treated, the average value of the relative dielectric constant was higher than when the PZT powder was not heat-treated, and the average value of the dielectric loss was low.

From this, it can be seen that better ferroelectric properties can be obtained when the PZT powder is heat-treated than when it is not heat-treated.
[Examples for examining the effect of heating temperature on piezoelectric material particles on piezoelectric film]
<Example 4-1>
1. Formation of Piezoelectric Film 1) Preparation of Piezoelectric Material Particles PZT (obtained from Sakai Chemical Industry Co., Ltd.), a raw material, is pulverized with a ball mill, and an average particle diameter of about 1 μm and PZT having a particle size distribution as shown in FIG. A fine powder was obtained. This fine powder was put into a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.), and the temperature in the furnace was increased to 500 ° C. at 400 ° C./1 h. After holding at 500 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. The particle size distribution after heating at 500 ° C. and the particle size distribution when heated at other temperatures are also shown in FIG. The particle size distribution was measured using a dry particle size distribution measuring device (HELOS & RODOS manufactured by Nippon Laser).
2) Film formation A glass plate was used as the substrate, and the PZT powder prepared in 1) was used as the material particles. On the substrate, the nozzle opening is 0.4 mm × 10 mm, the deposition chamber pressure is 300 Pa, the aerosol chamber pressure is 40000 Pa, the carrier gas type He, the gas flow rate is 4.0 liters / min, and the nozzle-substrate distance is 10 to 30 mm. Was applied to form a piezoelectric film. The thickness of the film was approximately 2 to 3 μm as measured by a step using a surface roughness meter.
3) Annealing treatment Subsequently, an annealing treatment of the PZT piezoelectric film was performed. The temperature of the muffle furnace was raised to 850 ° C. at 400 ° C./1 h, the substrate on which the piezoelectric film was formed was put, and held at 850 ° C. for 30 minutes. Thereafter, the inside of the furnace was cooled by natural cooling.
2. Observation of Piezoelectric Film Cross Section The substrate on which the PZT piezoelectric film was formed as described above was cut in the thickness direction, and the cross section was photographed and observed with a FE-SEM: field emission type operation electron microscope.

<Example 4-2>
In adjusting the PZT piezoelectric material particles, the PZT piezoelectric film was formed in the same manner as in Example 4-1, except that the muffle furnace was heated to 700 ° C. and held at 700 ° C. for 3 hours, and the cross section of the piezoelectric film was observed. did.

[Observation results]
The piezoelectric film states in Examples 4-1 and 4-2 are shown in FIGS. 6A and 6B. It shows a state in which a PZT piezoelectric film is formed on the lower glass plate.

  6A and 6B, it can be seen that when heat treatment is performed at 700 ° C., fewer voids are generated in the piezoelectric film than when heat treatment is performed at 500 ° C.

This is presumably because the powder resin that did not evaporate at the time of heat treatment at 500 ° C. was evaporated by heat treatment at 700 ° C. In addition, it is thought that the space | gap which has arisen in 700 degreeC is based on chemical adsorption water.
[Examples for investigating the relationship between heat treatment and crystallization of piezoelectric material particles]
<Example 5-1>
1. Preparation of Piezoelectric Material Particles PZT (obtained from Sakai Chemical Industry Co., Ltd.) as a raw material was pulverized with a ball mill to obtain PZT fine powder having an average particle diameter of about 1 μm and a particle size distribution as shown in FIG. This fine powder was put into a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.), and the temperature in the furnace was increased to 600 ° C. at 400 ° C./1 h. After holding at 600 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out.
2. X-ray diffraction measurement The PZT fine powder heat-treated in 1 was subjected to X-ray diffraction measurement by RINT2000 manufactured by Rigaku Corporation. Measurement conditions: Goniometer: RINT2000 vertical goniometer, Attachment: thin film, standard multipurpose sample stand, Monochromator: fixed monochromator, ScanningMode: 2Theta / Theta, ScanningType: Continuos Scanning, X-Ray: Cu excitation source 40kV / 40mA, divergence Slit: 1 °, divergence length limiting slit: 10 mm, scattering slit: 1 °, light receiving slit: 0.15 mm, monochrome light receiving slit: 0.6 mm.

<Example 5-2>
PZT piezoelectric material particles were prepared in the same manner as in Example 5-1, except that the muffle furnace was heated to 800 ° C. and maintained at 800 ° C. for 3 hours in the adjustment of the PZT piezoelectric material particles. went.

<Comparative Example 5-1>
PZT piezoelectric material particles were prepared in the same manner as in Example 5-1, except that the PZT powder was not heat-treated in the adjustment of the PZT piezoelectric material particles, and X-ray diffraction measurement was performed.

[Measurement result]
The change in the X-ray diffraction measurement values in Examples 5-1 and 5-2 and Comparative Example 5-1 is shown in the graph of FIG.

  In the graph of FIG. 7, the half-value widths (widths of waveforms having peaks) in Examples 5-1 and 5-2 and Comparative Example 5-1 are 0.5 °, 0.45 °, and 0.6 °, respectively. Met. Moreover, the peak became high in order of Comparative Example 5-1, Example 5-1, and Example 5-2.

In general, it can be said that crystallization progresses as the peak rises and the half-value width decreases. Therefore, crystallization progresses more when heat treatment is performed than when heat treatment is not performed, and heat treatment is performed at 600 ° C. When compared with the case of heat treatment at 800 ° C., it can be said that the heat treatment at 800 ° C. is more advanced than the case of heat treatment at 600 ° C. In other words, the amount of water of crystallization is lower when heat treatment is performed than when heat treatment is not performed, so even if annealing is performed at a high temperature, the amount of gas generated can be reduced and the film can be destroyed. Leads to prevention.
[Example of examining heat treatment and thermogravimetric change of piezoelectric material particles]
<Example 6>
A PZT powder of 165.750 mg was measured using a differential thermobalance measuring device (TG-8120, manufactured by Rigaku). The atmosphere was heated at 200 ml / min air, room temperature from 25 ° C. to 10 ° C./min, and the sampling time was 1 s. Weight (TG) and differential heat (DTA) were measured.

[Measurement result]
The measurement results of thermogravimetry and differential heat are shown in the graph of FIG.

From the graph of FIG. 8, the weight reduction rate at 180 ° C. by thermogravimetry is 0.08%, which is 0.15% or less. Further, it is 0.113% at 600 ° C. and 0.116% at 900 ° C., which are 0.18% and 0.2% or less, respectively.
[Example of examining the relationship between heat treatment of piezoelectric material particles and electrical characteristics]
<Example 7-1>
1. Formation of Piezoelectric Film 1) Preparation of Piezoelectric Material Particles PZT (obtained from Sakai Chemical Industry), which is a raw material, is pulverized by a ball mill, and a fine powder of PZT having an average particle diameter of about 1 μm and a particle size distribution as shown in FIG. Got. The particle size distribution was measured using a dry particle size distribution measuring apparatus (HELOS & RODOS manufactured by Nippon Laser). This fine powder was put into a muffle furnace (FP100 manufactured by Yamato Kogyo Co., Ltd.), and the temperature in the furnace was increased to 600 ° C. at 400 ° C./1 h. After holding at 600 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out.
2) Film formation An alumina substrate was used as a substrate, and a piezoelectric film was formed thereon by the AD method using the PZT powder prepared in 1), and a Ti / Pt electrode layer was formed thereon by a sputtering method. The film forming conditions of the PZT piezoelectric film by the AD method are: nozzle opening 0.4 mm × 10 mm, film forming chamber pressure 300 Pa, aerosol chamber pressure 40000 Pa, carrier gas type He, gas flow rate 4.0 liter / min, nozzle-substrate Aerosol was sprayed at a distance of 10 to 30 mm to form an insulating film. The thickness of the film was approximately 8 μm as measured by a step using a surface roughness meter.
3) Annealing treatment Subsequently, an annealing treatment of the PZT piezoelectric film was performed. The temperature of the muffle furnace was raised to 850 ° C. at 400 ° C./1 h, the substrate on which the piezoelectric film was formed was put, and held at 850 ° C. for 30 minutes. Thereafter, the inside of the furnace was cooled by natural cooling.
2. Test On the substrate on which the PZT piezoelectric film and the Ti / Pt electrode were formed as described above, an upper electrode of 125 μm × 200 μm was formed with an Au coater, and the relative dielectric constant and capacitance were measured. Both the dielectric constant and the capacitance were measured with an impedance analyzer HP-4194A manufactured by Hewlett-Packard Company.

<Example 7-2>
PZT fine powder pulverized in the same manner as in Example 7-1 was placed in a muffle furnace, and the temperature in the furnace was increased to 700 ° C. at 400 ° C./1 h. After maintaining at 700 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, a PZT piezoelectric film and a Ti / Pt electrode were formed on an alumina substrate in the same manner as in Example 7-1, annealed, and then tested.

<Example 7-3>
PZT fine powder pulverized in the same manner as in Example 7-1 was placed in a muffle furnace, and the temperature in the furnace was increased to 800 ° C. at 400 ° C./1 h. After holding at 800 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, a PZT piezoelectric film and a Ti / Pt electrode were formed on an alumina substrate in the same manner as in Example 7-1, annealed, and then tested.

<Example 7-4>
PZT fine powder pulverized in the same manner as in Example 7-1 was placed in a muffle furnace, and the temperature in the furnace was increased to 900 ° C. at 400 ° C./1 h. After holding at 900 ° C. for 3 hours, the inside of the furnace was cooled by natural cooling, and the fine powder was taken out. Using the treated particles, a PZT piezoelectric film and a Ti / Pt electrode were formed on an alumina substrate in the same manner as in Example 7-1, annealed, and then tested.

[Measurement result]
About Example 7-1 to 7-4, the squareness ratio which is the electrostatic capacitance with respect to a voltage is shown in FIG. 12 with a dielectric constant.

From FIG. 12, it can be seen that as the annealing temperature of the powder increases, the squareness ratio, which is the ratio of the applied voltage when the polarization direction changes with respect to the remanent polarization, increases, and the ferroelectric characteristics increase. This is the maximum around 800 ° C. If the temperature is higher than this, the range of particles suitable for film formation is exceeded, and the density of the film is reduced. On the other hand, the squareness ratio is deteriorated, so that the ferroelectric characteristics are deteriorated.
Manufacturing Method of Inkjet Head A method of manufacturing an inkjet head using the piezoelectric film of the present invention described above will be briefly described with reference to FIGS.

  First, the nozzle plate 12, the manifold plate 13, the flow path plate 14, the pressure chamber plate 15, and the vibration plate 2 having the structure described above with reference to FIG. 1 are manufactured (S11).

  Next, as shown in FIG. 1, the manifold plate 13 is joined to the upper surface of the nozzle plate 12, and the flow path plate 14 is joined to the upper surface of the manifold plate 13 (S12). These are joined together by an epoxy-based thermosetting adhesive.

  Next, as shown in FIG. 2, the diaphragm 2 is joined to the upper surface of the pressure chamber plate 15 (S13). Thereafter, the piezoelectric film 3 of the present invention is formed on the upper surface of the diaphragm 2 by the aerosol deposition method (AD method) using the apparatus described in relation to FIG. 3 (S14).

  Next, the electrodes 4 and lead portions are formed on the formed piezoelectric film 3 by photolithography / etching, screen printing, or the like (S15). Thereafter, a strong electric field is applied between the upper electrode 4 and the diaphragm 2 to polarize the piezoelectric film 3 (S16).

  Finally, the pressure chamber plate 15 is joined to the upper surface of the flow path plate 14 (S17). Thereby, the ink flow path forming body 11 as shown in FIG. 1 and the ink jet head 10 including the actuator plate 1 are completed.

  The technical scope of the present invention is not limited by the above-described embodiments, and, for example, those described below are also included in the technical scope of the present invention. In addition, the technical scope of the present invention extends to an equivalent range.

  In the above embodiment, the case where the piezoelectric film 3 is directly formed on the vibration plate 2 has been described. However, an intermediate layer such as a lower electrode is separately provided on the vibration plate, and the piezoelectric film is formed thereon. Even if it is a case, the manufacturing method of this invention is applicable similarly.

  In the above embodiment, the case where the present invention is applied to the formation of the piezoelectric film 3 in the actuator plate 1 has been described. For example, an insulating layer having various functions such as a diffusion prevention layer is provided between the piezoelectric film and the diaphragm. In the case of forming with ceramics, the manufacturing method of the present invention can be applied in the same manner.

It is a sectional side view of the inkjet head of this embodiment. 2A is a side sectional view showing a state in which the diaphragm is joined to the pressure chamber plate in the manufacturing process of the actuator plate, FIG. 2B is a side sectional view showing a state in which the piezoelectric film is formed, and FIG. 2C is a state in which the upper electrode is formed. It is a sectional side view shown. It is the schematic of a film-forming apparatus. FIG. 4A is a side sectional view showing the state of the piezoelectric film in the annealing step when using material particles that are not subjected to heat treatment, and FIG. 4B is the state of the piezoelectric film in the annealing step when using material particles that have been subjected to heat treatment. FIG. 3 is a flowchart schematically showing a procedure for manufacturing a piezoelectric film. 6A is a photograph of a cross section of the substrate when heat-treated at 500 ° C., and FIG. 6B is a photograph of a cross-section of the substrate when heat-treated at 700 ° C. It is a graph which shows the result of a X-ray-diffraction measurement about the case where a piezoelectric material particle is heated and it is not. It is a graph which shows the measurement result of the thermogravimetric and differential heat of a piezoelectric material particle. It is a flowchart which shows the manufacture procedure of an inkjet head roughly. It is a figure which shows the particle size distribution before and behind heat processing of an alumina powder. It is a figure which shows the particle size distribution before and behind heat processing of PZT powder. It is a figure which shows the relationship between the heat processing with respect to PZT powder, and an electrical property.

Explanation of symbols

1 ... Actuator plate (piezoelectric actuator)
2 ... Diaphragm (substrate)
3. Piezoelectric film (film)
4 ... Upper electrode (electrode layer)
10: Inkjet head 11: Channel unit (ink channel forming body)
16 ... Pressure chamber 16A ... Opening 19 ... Ink discharge nozzle 20 ... Ink M ... Material particles (ceramic particles, piezoelectric material particles)
Z ... Aerosol

Claims (18)

A heat treatment step of heat treating the ceramic particles;
A film forming step of forming a film by spraying an aerosol containing the ceramic particles after the heat treatment step on a substrate and attaching the ceramic powder;
An annealing process for annealing the film;
The manufacturing method of the film | membrane containing this.   The method for producing a film according to claim 1, wherein a heating temperature in the heat treatment step is equal to or higher than a temperature at which chemically adsorbed water contained in the ceramic particles is released.   The film manufacturing method according to claim 1, wherein a heating temperature in the heat treatment step is equal to or higher than an annealing temperature in the annealing treatment step.   The film manufacturing method according to claim 1, wherein a heating temperature in the heat treatment step is 450 ° C. to 850 ° C.   The method for producing a film according to claim 1, wherein the heating time in the heat treatment step is 30 minutes or more.   The manufacturing method of the film | membrane of Claim 1 which performs a dry-type grinding | pulverization process after the said heat processing process.   The method for producing a film according to claim 1, wherein the ceramic particles are particles of a piezoelectric material.   Furthermore, the ceramic particles, a mixed powder generation step of mixing a plurality of raw material powders to obtain a mixed powder, a sintered body generation step of obtaining a sintered body to be the ceramic material by firing the mixed powder, The method for producing a film according to claim 1, comprising: obtaining a ceramic material powder by pulverizing the sintered body.   The method for producing a film according to claim 1, wherein the ceramic particles are α-alumina particles.   The method for producing a film according to claim 1, wherein the ceramic particles are particles of lead zirconate titanate. An ink flow path forming body provided with a plurality of pressure chambers that communicate with an ink discharge nozzle for discharging ink and that has an opening that opens on one side;
A piezoelectric actuator comprising: a diaphragm provided on one surface side of the ink flow path forming body so as to close the opening; and a piezoelectric film laminated on the diaphragm;
A method of manufacturing an inkjet head comprising:
A heat treatment step of heat treating the particles of the piezoelectric material;
A piezoelectric film forming step of forming a piezoelectric film by spraying an aerosol containing particles of the piezoelectric material after the heat treatment step on the diaphragm and attaching the particles of the piezoelectric material;
An annealing process for annealing the piezoelectric film;
An electrode layer forming step of forming an electrode layer on the piezoelectric film;
A method for manufacturing an ink-jet head comprising:   The method of manufacturing an ink jet head according to claim 11, wherein a heating temperature in the heat treatment step is equal to or higher than a temperature at which chemically adsorbed water contained in the particles of the piezoelectric material is released.   The method of manufacturing an ink jet head according to claim 11, wherein a heating temperature in the heat treatment step is equal to or higher than an annealing temperature in the annealing step.   The method of manufacturing an ink jet head according to claim 11, wherein a heating temperature in the heat treatment step is 450 ° C. to 850 ° C.   The method for manufacturing an ink jet head according to claim 11, wherein the heating time in the heat treatment step is 30 minutes or more.   The manufacturing method of the inkjet head of Claim 11 which performs a dry-type grinding | pulverization process after the said heat processing process.   Furthermore, a mixed powder generating step for obtaining a mixed powder by mixing plural kinds of raw material powders with the particles of the piezoelectric material, and a sintered compact generating step for obtaining a sintered body to be the piezoelectric material by firing the mixed powder And a powder generating step of pulverizing the sintered body to obtain a powder of a piezoelectric material.   The method of manufacturing an ink jet head according to claim 11, wherein the particles of the piezoelectric material are particles of lead zirconate titanate.