KR100307769B1 - Long-term preserving method of piezoelectric/electrostrictive ceramic paste processed at a low temperature - Google Patents

Abstract

The present invention is prepared by a non-explosive oxidation-reduction combustion reaction at a low temperature of 100-500 ℃, the particle size is 5㎛ or less, ceramic oxide powder based on lead (Pb), titanium (Ti) and water or Preparation of a piezoelectric / electric warp ceramic paste precursor by adding an organic solvent for controlling physical properties to the ceramic oxide powder prepared on the basis of an organic solvent, and dissolving a ceramic component based on water or an organic solvent to separately prepare a ceramic sol solution The present invention relates to a method for securing long-term preservation of piezoelectric / electrical-distortion ceramic pastes by minimizing the deterioration of properties of the piezoelectric / electrical-distortion ceramic pastes by long-term preservation. Changes can be minimized to ensure quality stabilization and to prevent piezoelectric / electrical distortion The production cost can be reduced by preventing the waste paste from being discarded and producing only the required amount.

Description

Long-term preserving method of piezoelectric / electrostrictive ceramic paste processed at a low temperature}

The present invention relates to a method for ensuring long-term storage of piezoelectric / distortion ceramic pastes, and more particularly, piezoelectric / electrically-distorted ceramics according to long-term storage by separately preparing piezoelectric / electric-distortion ceramic paste precursors and ceramic sol solutions. The present invention relates to a method of minimizing a change in physical properties of a paste.

Ceramic oxide powder, which is used as a raw material in the manufacture of various devices using ceramics such as inkjet heads, memory chips, and piezoelectric materials, has an emphasis on miniaturization of unit particles and uniformity of particle size distribution. This is because the reactivity and applicability can be improved by reducing or charging the particles.

In manufacturing various film-type devices using ceramics, a method of manufacturing ceramic paste using ceramic oxide powder, printing or molding the same on a substrate, and then performing heat treatment has been mainly used.

In order to manufacture the ceramic paste, conventionally, as shown in Figure 1, a binder (binder) to secure the intrinsic properties as a paste, uniformly dispersing the ceramic particles to uniform the paste and suitable fluidity for applying to printing or molding A ceramic particle having an average particle diameter of 1 μm manufactured by a solid phase method was added to a solution in which a vehicle to be imparted, a plasticizer to enable fine molding, a dispersant to impart homogeneity to a paste, and the like were dissolved in a solvent. Then mixing and stirring have been used.

In this case, a cellulose fiber such as ethyl cellulose is used as the binder, phthalate is used as a plasticizer, and terpeneol is mainly used as a solvent.

In the case of using the ceramic oxide powder prepared by the conventional solid state method, the above organic substances must be added. If the organic substances are not added, the viscosity of the ceramic paste is not controlled, and the coating is made when the ceramic paste is coated on the substrate. There is a problem.

In addition, the ceramic paste prepared by this method is impossible to form at low temperatures because of the large size of the ceramic particles, the dispersant has a disadvantage that one-sided must be dependent on the supplier without any information on the composition or the manufacturing method.

In order to manufacture a ceramic film using the ceramic paste prepared by the above method, the ceramic paste is printed on a substrate and dried at 130 ° C. and heat treated at 1000 ° C. or higher. There is a problem that a separate additional heat treatment should be performed at 500 ° C. or higher for the binder removal operation.

In addition, there is a problem that the range of the selectable substrate is limited because the heat treatment at 1000 ℃ or more.

In order to solve the above problems, the applicant is prepared by non-explosive redox combustion reaction at a low temperature of 100-500 ℃ as shown in Figure 2 and the particle size is 5㎛ or less, lead (Pb), titanium ( A method of preparing a piezoelectric / electric warp ceramic paste by mixing a ceramic oxide powder having Ti as a basic component and a ceramic sol solution having the same or similar components as the ceramic oxide powder prepared based on water or an organic solvent is presented. .

These piezoelectric / electric warp ceramic pastes can be made without heat treatment at low temperatures due to the excellent physical properties of the fine ceramic oxide powder and the surface activity by sol coating. There are many advantages, such as no need for a separate heat treatment process.

When the piezoelectric / electric warp ceramic paste is manufactured in a small amount and used for a short time, deterioration of physical properties due to storage is not a big problem.

However, in order to uniformize the quality of the manufactured device, it is preferable to manufacture and use a large amount of piezoelectric / distortion ceramic pastes, and in the case of long-term manufacturing and use in large quantities, it is possible to minimize the physical properties of organic materials. Since the solvent is used, the physical properties may be degraded due to the deterioration of the dispersibility and the viscosity change due to the evaporation of the solvent.

In order to solve the above problems, the present invention manufactures piezoelectric / electric warp ceramic paste precursors which ensure the dispersibility of piezoelectric / electric warp ceramic paste, and if necessary, only a necessary amount is mixed with sol for a short time to prepare piezoelectric / electric warp ceramic paste manufacturing time. By minimizing the quality change by supplying the required amount of fresh piezoelectric / distortion ceramic paste at all times, and the method of minimizing the deterioration of properties due to long-term storage or the amount of piezoelectric / distortion ceramic paste discarded without being used. The purpose is to provide.

1 schematically illustrates a method of manufacturing a conventional piezoelectric / distortion ceramic paste,

Figure 2 schematically shows a general method for manufacturing a low temperature forming piezoelectric / electrostrictive ceramic paste,

Figure 3 schematically shows the process of the long-term storage stability method of the low-temperature molding piezoelectric / distortion ceramic paste.

The present invention for achieving the above object is produced by non-explosive oxidation-reduction combustion reaction at a low temperature of 100-500 ℃, the particle size is 5㎛ or less, and lead (Pb), titanium (Ti) as a basic element A piezoelectric / electric warp ceramic paste precursor is prepared by adding a ceramic oxide powder and an organic solvent for controlling physical properties to the ceramic oxide powder prepared on the basis of water or an organic solvent, and dissolving the ceramic component based on water or an organic solvent. By separately preparing a ceramic sol solution, and by mixing only the necessary amount if necessary, there is a feature of the long-term preservation of the piezoelectric / electrostrictive ceramic paste that can minimize the deterioration of physical properties of the piezoelectric / electrostrictive ceramic paste.

Hereinafter, the present invention will be described in detail.

Piezoelectric / electric warp ceramic paste precursors are prepared by adding an organic solvent for controlling physical properties to ceramic oxide powder, and a small amount of organic material may be added.

In the present invention, the ceramic oxide powder used as a raw material of the piezoelectric / electric warp material is prepared by dissolving or uniformly dispersing the ceramic component material in a solvent or a dispersion medium to prepare a solution or dispersion mixture containing the ceramic component. Preparing a mixed solution by adding citric acid or an amount or more necessary to cause an oxidation-reduction combustion reaction with the anion of the ceramic component to a solution or dispersion mixture in which the components are dissolved or dispersed, and heat-treating the mixed solution at 100-500 ° C. It is prepared, including the step, may further comprise the step of further heat treatment at 700-900 ℃ to increase the crystallinity.

The raw material containing the ceramic component is selected from a ceramic component such as an oxide, carbonate or nitrate of the ceramic component, a salt of an organic or inorganic substance, or a complex of ceramic components.

As the ceramic component, it is preferable to use a piezoelectric / electrically distorted ceramic element having lead (Pb) and titanium (Ti) as a basic component, and in particular, the ceramic component may include lead (Pb), zirconium (Zr), or titanium (Ti). ) Or a component composed of lead (Pb), magnesium (Mg) and niobium (Nb).

As a solvent or dispersion medium for dissolving or dispersing the ceramic component raw material, one or more selected from among those capable of dissolving or dispersing the raw material containing the ceramic component in water or an organic solvent is used. Among the organic solvents, dimethyl formamide, methoxyethanol, acetic acid, alcohols and glycols are mainly used.

As a combustion aid, citric acid, an organic compound that can cause a combustion reaction, is used. In the conventional method, citric acid has been used to impart homogeneity of the reaction as a complexing agent, not as a combustion aid, and has been applied in processes such as the Pechini process. By using can cause a controlled combustion reaction rate.

Citric acid is added to a solution or dispersion mixture in which ceramic components are dissolved or dispersed to prepare a mixed solution. The amount of citric acid to be added is added to the amount or more necessary to cause an oxidation-reduction combustion reaction with the anion of the ceramic element. The rate of progress of the reaction can be controlled depending on the amount of citric acid added.

The mixed solution mixed with citric acid is heat-treated at 100-500 ° C. As the temperature of the heat treatment increases, the crystallinity of the ceramic phase increases, but when the heat treatment temperature is 100 ° C. or higher, the combustion reaction of citric acid can be sufficiently initiated. The reaction may occur even when the heat treatment is performed above 500 ° C., but the heat treatment is performed at a higher temperature. Is meaningless compared to conventional methods.

More preferably, the heat treatment is carried out at 150-300 ° C., and the temperature range can adequately secure the crystallinity of the ceramic phase even at a very low temperature.

Citric acid is removed during the combustion reaction, and ceramic oxide is formed without scattering by the heat of reaction of citric acid generated at this time.

In this reaction, components other than the ceramic component are removed by a combustion reaction for a sufficient time, thereby forming a ceramic oxide powder in a pure form in which impurities do not remain.

The ceramic oxide powder prepared by the above method is an extremely fine and uniform particle size distribution having a particle size of 5 μm or less, especially 0.5 μm or less, and the primary particles are in the form of an individual or a soft aggregate. It is a fully burned ceramic phase, so the weight is not reduced by further heat treatment.

In addition, since the surface is excellent in reactivity and can be formed only by heat treatment at low temperature, the degree of freedom of the diaphragm is high, and various methods of printing or coating the diaphragm can be applied.

In order to increase the crystallinity of the ceramic oxide powder prepared, the ceramic oxide powder prepared may be further heat treated at 700-900 ° C.

It is preferable to use PZT, PMN or their solid solution (PZT-PMN) composite oxide as the ceramic oxide.

In addition, the ceramic oxide is nickel (Ni), lanthanum (La), barium (Ba), zinc (Zn), lithium (Li), cobalt (Co), cadmium (Cd), cerium (Ce), chromium (Cr), Antimony (Sb), iron (Fe), yttrium (Y), tantalum (Ta), tungsten (W), strontium (Sr), calcium (Ca), bismuth (Bi), tin (Sn), manganese (Mn) It may further comprise one or more elements.

In order to secure the stability of the piezoelectric / electric warp ceramic paste and the fluidity necessary for molding, an organic solvent for controlling physical properties is added to the ceramic oxide powder. Various physical solvents may be used as the organic solvent for controlling physical properties, but it is preferable to use glycols, alcohols or ketones having a certain viscosity and low vapor pressure at room temperature.

In the case of adding an organic solvent for controlling physical properties to the ceramic oxide powder, the amount of the organic solvent for controlling physical properties is preferably 1-100 parts by weight based on the ceramic oxide powder. This is because if the amount of the organic solvent for controlling physical properties is less than 1 part by weight, the effect of adding the organic solvent for controlling physical properties is not effective, and if the amount is more than 100 parts by weight, the mixture does not maintain viscosity and is too diluted to deteriorate moldability during molding.

The addition amount of the organic solvent for controlling the physical properties is particularly preferably 10 to 40 parts by weight based on the ceramic oxide powder. In this range, the organic solvent for controlling the physical properties can be added while maintaining the viscosity of the mixture as appropriate.

In addition, a small amount of organic matter may be added to improve the dispersibility and homogeneity of the mixture in which the solvent for controlling physical properties is added to the ceramic oxide powder. At this time, it is preferable to use long-chain alcohols or polar organic solvents to add.

Of the long chain alcohols, it is preferable to use pentanol or hexanol, and it is preferable to use acetylacetone or methoxyethanol as the polar organic solvent.

It is preferable that the addition amount of an organic substance shall be 1-100 weight part with respect to a ceramic oxide powder. This is because if the added amount of the organic substance is less than 1 part by weight, there is no effect of adding the organic substance. If the added amount is more than 100 parts by weight, the mixture does not maintain the viscosity and is too diluted, resulting in poor moldability.

The addition amount of the organic material is particularly preferably 10 to 40 parts by weight based on the ceramic oxide powder. In this range, the addition of the organic material can be effected while maintaining the viscosity of the mixture as appropriate.

A piezoelectric / electric distortion ceramic paste precursor is produced by the above method. Since the prepared piezoelectric / electric warp ceramic paste precursor uses only an organic solvent having little volatileness, evaporation of the solvent over a long period of time is suppressed, and long-term dispersibility can be maintained due to the characteristics of the fine powder.

The prepared piezoelectric / electric warp ceramic paste precursor may be used as it is or may be used by treating with a 3-roll mill or a ball mill.

When the dispersibility is low due to a long retention period of the piezoelectric / electric warp ceramic paste precursor, stirring, shaking, and ultrasonic dispersion are performed. By such a simple treatment, the piezoelectric / electric warp ceramic paste precursor may restore initial dispersibility.

Ceramic sol solutions of the same or similar components having affinity with the ceramic oxide powder for mixing with the ceramic oxide powder are prepared separately.

Ceramic sol solutions are prepared by dissolving ceramic components based on water or organic solvents. Various organic solvents can be used as the base, but it is preferable to use mainly selected from acetic acid, dimethylformamide, methoxyethanol, alcohols, and glycols.

The ceramic component used in the manufacture of the ceramic sol solution is preferably a component containing lead (Pb), zirconium (Zr), titanium (Ti), the concentration of the ceramic sol solution to be used is 0.1-5M It is preferable.

The piezoelectric / electric warp ceramic paste precursor and the ceramic sol separately prepared by the above methods are stored separately, and when necessary, only the necessary amount is mixed for a short time to prepare the piezoelectric / electric warp ceramic paste.

When the ceramic oxide powder and the ceramic sol solution are mixed, the content of the ceramic sol solution is preferably 1-200 parts by weight based on the ceramic oxide powder. This is because when the content of the ceramic sol solution is 200 parts by weight or more, the ceramic oxide powder is diluted too much, so that the viscosity of the mixture is low, and when the content of the ceramic sol solution is less than 1 part by weight, the amount of the ceramic oxide powder is too large and the viscosity becomes too high.

The method of the present invention as described above is schematically shown in FIG. 3, by separately preparing a ceramic paste precursor and a ceramic sol solution, and using only a necessary amount when necessary to minimize deterioration of physical properties due to long-term storage.

(Comparative Example 1)

5 g of PZT-PMN fine powder was mixed with 0.7 g of trimethylene glycol and 0.5 g of methoxyethanol and stirred for 5 hours in an automatic induction. 2.0 M PZT-acetic acid sol 2.0g was added to the obtained liquid mixture, and it stirred further for 30 minutes, and completed the piezoelectric / electric distortion ceramic paste.

After storing the finished piezoelectric / distortion ceramic paste for 10 days, the physical properties of the piezoelectric / distortion ceramic paste were observed to confirm that the dispersibility was lowered and the viscosity changed considerably.

(Example 1)

5 g of PZT-PMN fine powder was mixed with 0.7 g of trimethylene glycol and 0.5 g of methoxyethanol and stirred for 5 hours in an auto-induction to prepare a piezoelectric / electric warp ceramic paste precursor. The prepared piezoelectric / electric warp ceramic paste precursors were stored for 10 days and then redispersed in an ultrasonic generator.

The paste was completed by adding 2.0 g of 2.0 M PZT-acetic acid sol to the redispersed piezoelectric / electric distortion ceramic paste precursor and stirring for 30 minutes.

As a result of observing the physical properties of the completed piezoelectric / distortion ceramic paste, it was confirmed that there was no change in physical properties even after long-term storage.

In the present invention as described above, by manufacturing a large amount of piezoelectric / electric warp ceramic paste precursor and ceramic sol separately and using only the required amount, the production time of the piezoelectric / electric warp ceramic paste can be shortened if necessary, so that smooth supply is possible, thereby improving productivity. Let's do it.

In addition, it is possible to prevent the piezoelectric / distortion ceramic paste from being discarded due to deterioration of properties during long-term storage and to reduce the production cost by producing only the required amount.

In addition, fresh piezoelectric / distortion ceramic pastes can always be supplied in the required amount, minimizing the change in quality, thereby stabilizing the quality.

Claims (11)

Prepared by non-explosive oxidation-reduction combustion reaction at a low temperature of 100-500 ℃, the particle size is 5㎛ or less, ceramic oxide powder with lead (Pb), titanium (Ti) as a basic element, water or organic solvent A piezoelectric / electric warp ceramic paste precursor was prepared by adding an organic solvent for controlling physical properties to the ceramic oxide powder prepared as a base. The ceramic sol solution is prepared separately by dissolving the ceramic component based on water or an organic solvent. A method of securing long-term preservation of piezoelectric / electric distortion ceramic pastes which can minimize the deterioration of properties of piezoelectric / electric distortion ceramic pastes due to long-term preservation by mixing only the necessary amount when necessary. The method of claim 1, wherein glycol, alcohols or ketones are used as the organic solvent for controlling physical properties. The method of claim 1, wherein the amount of the organic solvent for controlling physical properties is 1-100 parts by weight based on the ceramic oxide powder. The method of claim 1, wherein a long chain alcohol or a polar organic solvent is added to the piezoelectric / electric distortion ceramic paste precursor to improve dispersibility and homogeneity. 5. The method of claim 4, wherein the addition amount of the long chain alcohol or the polar organic solvent is 1-100 parts by weight based on the ceramic oxide powder. The method of claim 1, further comprising the step of preparing the piezoelectric / electrostrictive ceramic paste precursor and then treating it with a 3-roll mill or a ball mill. Long-term preservation of paste. 2. The method of claim 1, wherein the piezoelectric / distortion ceramic paste precursor is re-dispersed by stirring, shaking, or ultrasonic dispersion when the dispersibility is low due to a long shelf life of the piezoelectric / distortion ceramic paste precursor. The method of claim 1, wherein acetic acid, dimethylformamide, methoxyethanol, alcohols, or glycols are used as the organic solvent serving as the base of the ceramic sol solution. The method of claim 1, wherein the ceramic component used in the preparation of the ceramic sol solution is a component of lead (Pb), zirconium (Zr), titanium (Ti), characterized in that the long-term How to ensure preservation. The method of claim 1, wherein the ceramic sol solution is used at a concentration of 0.1-5M. The method of claim 1, wherein the content of the ceramic sol solution is 1-200 parts by weight based on the ceramic oxide powder when the ceramic oxide powder is mixed with the ceramic sol solution.