KR20130102222A - Piezoelectric material and it's fabrication method for haptic device using multi-layer actuator - Google Patents

Abstract

PURPOSE: A piezoelectric material for a multilayer actuator in a haptic device and a fabrication method thereof are provided to minimize power consumption by performing a sintering process at a low temperature. CONSTITUTION: Copper oxide of 0.1 to 10 mole% is added to a compound. The compound is indicated as a chemical formula 1. A haptic device is laminated by using a piezoelectric material. A mixture is manufactured by a wet mixing process (S110). A first powder is formed by drying the mixture (S120). [Reference numerals] (S110) Step where a below-mentioned compound is produced by wet-mixing raw powder including PbO,ZrO_2,TiO_2,NiO,ZnO, and Nb_2O_5 according to a mol rate; (S120) Step where the compound is dried and calcined at around 700-1,000 °C in order to create a first powder; (S130) Step where copper oxide of 0.1 to 10 mole % is added to the first powder and the powder is wet-mixed and dried to produce a second powder; (S140) Step where the second powder is pressed and sintered at around 700-1,000 °C in order to create a piezoelectric body

Description

Piezoelectric material for multilayer actuator and its manufacturing method for haptic device application {Piezoelectric material and it`s fabrication method for haptic device using multi-layer actuator}

The present invention relates to a piezoelectric body for a laminated actuator having a high piezoelectric strain constant and low dielectric constant, which can be sintered at a low temperature of 1000 ° C. or lower using an oxide, and a method of manufacturing the same.

Piezoelectric material is a material that can convert the electrical energy and mechanical energy applied to each other, piezoelectric transformers, ultrasonic vibrators, electromechanical ultrasonics widely applied to ultrasonic devices, imaging equipment, audio equipment, sensors, communication equipment It is widely used as a material for components such as transducers, ultrasonic motors, actuators, filters, and resonators.

In general, in order to apply a piezoelectric body to an actuator, the piezoelectric strain constant, the electromechanical coupling coefficient, and the dielectric constant must be low. In addition, in order to use the multilayer actuator, it is required to have excellent dielectric and piezoelectric properties, that is, high piezoelectric strain constant and low dielectric constant, even though the piezoelectric material is sintered at a low temperature of 1000 ° C. or less depending on the metal type of the electrode.

Conventional piezoelectric materials based on Pb (Zr, Ti) O ₃ [PZT] can significantly change the electromechanical coupling coefficient, mechanical quality coefficient, relative dielectric constant, etc. according to the combination of Zr and Ti and the addition of impurities. Because of the small change, many studies have been conducted by the researchers.

The PZT ceramics have a sintering temperature of 1200 ° C. or more, and Pb (Ni, Nb) O ₃ [PNN], Pb (Zn, Nb) O ₃ [PZN], Pb (Mn, Nb) O ₃ [PMN] Piezoelectric and dielectric properties are dramatically increased when a new phase co-existence region is employed by employing a relaxor material such as the back.

Particularly, in the case of the piezoelectric strain constant d ₃₃ , a high value of about 650 pC / N or more can be obtained, but as the piezoelectric strain constant increases, the dielectric constant also increases. When a piezoelectric material having a high dielectric constant is applied to a stacked actuator, the capacitance of the laminate on which the piezoelectric material is laminated increases, which increases the power consumption of the entire actuator element.

In addition, since the capacitance of the laminate increases in proportion to the number of laminated layers of the piezoelectric body, the number of laminated layers of the piezoelectric body should be limited in order to reduce the capacitance. However, when the number of laminated layers is limited, it is difficult to obtain a high piezoelectric strain.

Therefore, there is a need for a piezoelectric body that sinters at a low temperature of 1000 DEG C or lower and has a high piezoelectric strain constant and low dielectric constant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric body for laminated actuators capable of sintering at a low temperature of 1000 ° C. or less and having a high piezoelectric strain constant and low dielectric constant.

Another object of the present invention is to provide a method of manufacturing the piezoelectric body.

In addition, another object of the present invention to provide a haptic device manufactured using the piezoelectric material.

In order to achieve the above object, the piezoelectric body for a multilayer actuator of the present invention is a copper oxide (CuO) added to the compound represented by the following Chemical Formula 1 at 0.1 to 10 mol%;

[Formula 1]

(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3

(Where x is 0.1 <x <0.5 and y is an integer of 0.1 <y ≦ 0.9).

Preferably x is 0.31 and y is an integer of 0.4.

In addition, the haptic actuator element of the present invention for achieving the above-described other object is laminated using the piezoelectric element for the laminated actuator.

In addition, the method of manufacturing a piezoelectric body for a multilayer actuator of the present invention for achieving the above another object is a molten raw material powder containing PbO, ZrO ₂ , TiO ₂ , NiO, ZnO and Nb ₂ O ₅ preparing a mixture by mixing according to the (mol) fraction and then wet mixing, drying the mixture and calcining at 700 to 1000 ° C. to form a first powder represented by Chemical Formula 1 below, oxidizing the first powder. Adding 0.1 to 10 mol% of copper (CuO), wet mixing, and drying to form a second powder, and sintering the second powder at 700 to 1000 ° C. after pressure molding to form a piezoelectric body;

[Formula 1]

(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3

(Where x is 0.1 <x <0.5 and y is an integer of 0.1 <y ≦ 0.9).

Preferably x is 0.31 and y is an integer of 0.4.

In the step of preparing the mixture, the raw powder is wet mixed with one solvent selected from the group consisting of methanol, ethanol, isopropanol and distilled water.

The method may further include polishing the piezoelectric material prepared in the forming of the piezoelectric body and applying an electrode material, and then polling at DC 3 to 5 kV / mm in a silicon oil bath at 120 ° C.

The electrode material is at least one selected from the group consisting of silver (Ag), copper (Cu), palladium (Pd), and nickel (Ni).

Since the piezoelectric body of the present invention can be sintered at a low temperature of 1000 ° C. or lower, any electrode material having a higher melting point than the sintering temperature can be used, so that an electrode material suitable for the purpose can be selected and used. Particularly, if a low-cost electrode material is used, a low-cost device can be provided.

In addition, the piezoelectric body of the present invention has a high piezoelectric strain constant and low dielectric constant even when sintered at a low temperature of 1000 ° C. or less, so that the number of laminated layers for providing a stacked actuator element is limited. That is, even if the number of stacked layers increases, power consumption of the entire device can be minimized. In addition, since the constraint of the number of laminated layers is small, it is possible to maximize the piezoelectric strain of the entire device.

In addition, since the piezoelectric body of the present invention can minimize the power consumption of the entire device, it can be applied to a haptic device for a mobile phone that requires low power consumption.

1 is a flowchart illustrating a method of manufacturing a piezoelectric body for a multilayer actuator according to an embodiment of the present invention.
2 is a diagram illustrating a device for a mobile phone haptic to which the piezoelectric body of the present invention is applied.
3 is a graph measuring XRD according to the amount of copper oxide added according to Examples 1 to 6 of the present invention.
4 is a graph measuring relative density, piezoelectric strain constant, dielectric constant, electromechanical coupling coefficient, and mechanical quality coefficient according to the Examples and Comparative Examples of the present invention.

The present invention relates to a piezoelectric body for a laminated actuator having a high piezoelectric strain constant and low dielectric constant and capable of sintering at a low temperature of 1000 ° C. or lower, and a method of manufacturing the same.

Hereinafter, the present invention will be described in detail.

In the piezoelectric body of the present invention, copper oxide (CuO) is added in an amount of 0.1 to 10 mol%, preferably 1 to 5 mol%, to the compound represented by the following Chemical Formula 1 (PZT-PZNN). For example, when copper oxide is added to Formula 1, it may be represented by the following Formula 2.

[Formula 1]

(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3

X is 0.1 <x <0.5, y is an integer of 0.1 <y ≦ 0.9, preferably x is 0.31, and y is an integer of 0.4.

[Formula 2]

(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3 + z mol% CuO

Z is an integer of 0.1 to 10.

The compound represented by Chemical Formula 1 is referred to as a PZT-PZNN compound because it consists of (Pb, Zr, Ti)-(Pb, Ni, Zn, Nb).

The piezoelectric body (PZT-PZNN + CuO) of the present invention, in which 0.1 to 10 mol% of copper oxide is added to the PZT-PZNN compound, has a low temperature of 1000 ° C or lower, preferably 900 ° C or lower, and more preferably 700 to 900 ° C. It can be sintered at, showing high piezoelectric strain constant (d ₃₃ ) and low dielectric constant.

When the copper oxide is added below the lower limit, the piezoelectric body cannot be sintered at a low temperature. When the copper oxide is added above the upper limit, a secondary phase associated with CuO is precipitated, and sintering proceeds excessively, causing a problem of melting during sintering.

The PZT-PZNN compound is made of a raw material powder containing PbO, ZrO ₂ , TiO ₂ , NiO, ZnO and Nb ₂ O ₅ .

Specifically, the compound is against PbO 1 mole (mol) ZrO ₂ 0.1 to 1 mole (mol), TiO ₂ 0.1 to 1 mole (mol), NiO 0.01 to 0.5 mole (mol) represented by Formula 1, ZnO 0.01 to 0.5 mol and 0.1 to 1 mol of Nb ₂ O ₅ .

When the raw powder is mixed in an amount outside the above range, a compound other than the compound represented by Chemical Formula 1 may be prepared.

The PZT-PZNN compound without the copper oxide may be used as a piezoelectric body alone, but the PZT-PZNN compound may be sintered when sintered at a high temperature of 1100 ° C. or higher, thereby causing various problems.

As a first problem, Pb is volatilized at a high sintering temperature to cause an imbalance in the composition of the PZT-PZNN compound. The compositional unbalance not only deteriorates the piezoelectric properties, but also causes the PZT-PZNN compound The yield of the product may be reduced during manufacture.

Also, as a second problem, there are limited electrode materials that can be used when applying the PZT-PZNN compound having a high sintering temperature to the lamination process. For example, since the melting point of silver used as an internal electrode is about 960 ° C, it can not be sintered at the same time as a PZT-PZNN compound capable of sintering at 1100 ° C or more. Therefore, Pd or the like having a high melting point can be used to overcome this problem. However, since the Pd and the like are expensive electrode materials, the unit price of the device using the PZT-PZNN compound may increase.

The piezoelectric material preferably has a high piezoelectric strain constant (d ₃₃ ) and a low dielectric constant in order to be applied to an actuator. The PZT-PZNN compound exhibits a high piezoelectric strain constant (d ₃₃ ) and a low dielectric constant. However, when the x value of Chemical Formula 1 is out of the range, the piezoelectric strain constant is lowered, so the x value should satisfy the above range. Lower piezoelectric strain constants mean lower piezoelectric properties.

Therefore, the piezoelectric material of the present invention can be sintered at 1000 ° C. or lower by adding copper oxide to the PZT-PZNN compound, so that an electrode material having low melting point and low melting point can be used. The electrode material may be one selected from the group consisting of silver (Ag), copper (Cu), palladium (Pd), and nickel (Ni)

In addition, the piezoelectric body of the present invention exhibits a high piezoelectric strain constant (d ₃₃ ) and a low dielectric constant similar to the PZT-PZNN compound to which copper oxide is not added.

In addition, the present invention provides a method of manufacturing a piezoelectric body for a laminated actuator, which will be described with reference to FIG.

In the piezoelectric method of the present invention, a raw powder including PbO, ZrO ₂ , TiO ₂ , NiO, ZnO, and Nb ₂ O ₅ is mixed according to a mole fraction according to Formula 1, followed by wet mixing to prepare a mixture. Step (S110), drying the mixture and calcining (calcination) at 700 to 1000 ° C to form a first powder (S120), to add a copper oxide (CuO) in 0.1 to 10 mol% to the first powder After wet mixing and drying to form a second powder (S130) and the second powder after pressure molding to form a piezoelectric by sintering at 700 to 1000 ℃ (S140).

In addition, after the step S140, the piezoelectric material prepared in step S140 is polished and the electrode material is applied, followed by polling for 40 to 80 minutes at a DC 3 to 5 kV / mm in a silicon onil bath at 120 ° C. (S150) It may further include. The electrode material is one or a combination of two materials selected from the group consisting of silver (Ag), copper (Cu), palladium (Pd), and nickel (Ni).

First, in step S110, the raw material powder containing PbO, ZrO ₂ , TiO ₂ , NiO, ZnO, and Nb ₂ O ₅ is mixed according to the mole fraction according to Chemical Formula 1 and placed in a nylon jar to nylon jar. Wet mix with ball and solvent for 4 to 36 hours.

In the step S110 it is possible to have a high piezoelectric strain constant and low dielectric constant by optimally design the composition of the PZT-PZNN compound by adjusting the mole fraction of the raw material powder.

The purity of the raw material powders does not affect the properties such as the piezoelectric strain constant, the dielectric constant, and the sintering temperature, but the preferable purity is 98% or more.

The solvent is not particularly limited as long as it can be wet-mixed with the raw material powder, but is preferably one selected from the group consisting of methanol, ethanol, isopropanol and distilled water.

Next, in step S120 to dry the solvent of the mixture ground by wet mixing in step S110 and then dried at 50 to 100 ℃ calcined for 1 to 10 hours at 700 to 1000 ℃ the first powder represented by the formula (1) To form. In Formula 1, x is 0.1 <x <0.5, y is an integer of 0.1 <y≤0.9, preferably x is 0.31, and y is an integer of 0.4.

Next, in step S130, 0.1 to 10 mol% of copper oxide (CuO) is added to the first powder formed in step S120, wet mixed with a solvent for 4 to 36 hours, and then dried at 50 to 100 ° C. to a second powder. To form a chemical formula 1 + CuO ((1-x) Pb (Zr _0.47 Ti _0.53 ) O ₃ -xPb ((Ni _1-y Zn _y ) _1/3 Nb _2/3 ) O ₃ + CuO).

In addition, in step S130, the process of wet mixing and drying the first powder to which the copper oxide is added may be repeatedly performed 1 to 6 times so that the copper oxide and the first powder may be well mixed and the size of the powder may be minimized.

Next, in step S140, the second powder prepared in step S130 is pressurized to a desired shape and then sintered at 700 to 1000 ° C. for 1 to 10 hours to form a piezoelectric body. The formed piezoelectric body can be sintered at 1000 ° C. or less by adding copper oxide, and exhibits high piezoelectric strain constant and low dielectric constant.

2 shows a device for a mobile phone haptic to which the piezoelectric body of the present invention is applied.

As shown in FIG. 2, the cell phone haptic element includes an internal electrode 11, an external electrode 12, a piezoelectric element 13, and an insulating layer 14, and the piezoelectric element 13 includes a plurality of layers.

Since the piezoelectric element 13 of the present invention exhibits a high piezoelectric strain constant and low dielectric constant, there is little restriction on the number of stacked layers, and the power consumption of the device in which the piezoelectric material is stacked can be minimized, thereby requiring low power consumption. Applicable to The haptic device is not limited to the haptic device shown in FIG. 2 and may be a conventional haptic device.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example 1.

0.3243 mol of ZrO _2, 0.3657 mol of TiO _2, 0.0413 mol of NiO, 0.0413 mol of ZnO and 0.2067 mol of Nb ₂ O ₅ with zirconia ball in nylon ego for 24 hours with ethanol using wet ethanol for 1 mol of Pb with purity over 98% To prepare a mixture. The wet mixing a _{0.69Pb (Zr 0 .47 Ti 0 .53} ) of the pulverized mixture was dried and calcined at 100 ℃ for 30 minutes at 850 ℃ for 4 hours chemically synthesized by O ₃ -0.31Pb ((Ni _{0. 6} Zn _{0 .4)} represented by _1/3 Nb _2/3) O ₃ The first powder was synthesized. After adding 0.5 mol% of copper oxide (CuO) corresponding to 1 mol of the first powder, wet mixing with ethanol for 48 hours and drying at 100 ° C. for 30 minutes was repeated 4 times to average particle size. A second powder of 0.69 Pb (Zr _0.47 Ti _0.53 ) O ₃ −0.31 Pb ((Ni _0.6 Zn _0.4 ) _1/3 Nb _2/3 ) O ₃ + 0.5 mol% CuO having a μm or less was prepared. The second powder was placed in a cylindrical shaped body having a diameter of 16 mm and a height of 1.2 mm, molded by applying a pressure of 100 kg / cm 2, and then sintered at 900 ° C. for 4 hours to prepare a piezoelectric body.

Examples 2-6.

In the same manner as in Example 1, each of the piezoelectric bodies was prepared by adding 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, and 5 mol% of the copper oxide to be added.

Example 7.

In the same manner as in Example 1, the piezoelectric material was prepared by sintering the second powder at 875 ° C.

Examples 8-12.

Example 3 was carried out in the same manner, each of the piezoelectric material was prepared by adding 1 mol%, 1.5 mol%, 2 mol%, 3 mol% and 5 mol% of copper oxide.

Example 13.

In the same manner as in Example 1, but the second powder was sintered at 925 ℃ to prepare a piezoelectric body.

Examples 14-18.

Each piezoelectric body was prepared in the same manner as in Example 13 except that the amounts of copper oxide added were 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, and 5 mol%, respectively.

Comparative Example 1

In the same manner as in Example 13, but without the addition of copper oxide to form a second powder was molded and sintered at 1100 ℃ to prepare a piezoelectric body.

Experimental Example 1. XRD measurement of Examples 1 to 6

Referring to FIG. 3 in which XRD was measured according to the amount of copper oxide (CuO) added, it was confirmed that a uniform PZT-PZNN phase was maintained without forming a secondary phase according to the amount of copper oxide added.

Therefore, it can be seen that addition of copper oxide does not affect the phase formation of the piezoelectric body.

Experimental Example 2. Measurement of relative density, piezoelectric strain constant (d ₃₃ ), permittivity (ε ₃₃ ^T _/ ε ₀ ), electromechanical coupling coefficient (k _p ), mechanical quality coefficient (Qm)

After polishing the piezoelectric materials prepared in Examples and Comparative Examples and applying silver with an electrode material, DC 3 to 5 kV / mm was provided for 60 minutes in a silicon oil bath at 120 ° C. and the characteristics of the piezoelectric body were passed after 24 hours. It measured, and it is shown in FIG.

Referring to FIG. 4, it was confirmed that when the amount of copper oxide added was 0.5 mol% or more, all except Example 7 had a high relative density of 96% or more. Since the relative density is used as a criterion for determining the sintering of the piezoelectric body, it was confirmed that the sintering was performed well regardless of the small amount of copper oxide when sintering at 900 ° C. or higher.

The piezoelectric strain constant, dielectric constant and electromechanical coupling coefficient increased as the relative density increased, and Examples 1 to 6 and 8 to 18 except Example 7 were sintered at 1100 ° C. without addition of copper oxide. It was found that similar piezoelectric strain constants = 600 pC / N (high piezoelectric strain constants) and dielectric constant = 1500 (low dielectric constants).

Therefore, it can be seen that the piezoelectric body of the present invention can be sintered at 900 ° C. or less without deterioration of properties as compared with PZT-PZNN (Comparative Example 1) compound having high piezoelectric strain constant and low dielectric constant.

11: internal electrode 12: external electrode
13: piezoelectric body 14: insulating layer

Claims (8)

Copper oxide (CuO) is added to the compound represented by the formula (1) to the piezoelectric laminate actuator, characterized in that 0.1 to 10 mol%;
[Formula 1]
(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3
(Where x is 0.1 <x <0.5 and y is an integer of 0.1 <y ≦ 0.9). The piezoelectric body for a multilayer actuator according to claim 1, wherein x is 0.31 and y is an integer of 0.4. A device for haptic, which is laminated using the piezoelectric body for the multilayer actuator according to claim 1. Preparing a mixture by mixing raw material powder including PbO, ZrO ₂ , TiO ₂ , NiO, ZnO, and Nb ₂ O ₅ according to a mole fraction according to Chemical Formula 1, followed by wet mixing;
Drying the mixture and calcining at 700 to 1000 ° C. to form a first powder represented by Formula 1 below;
Adding 0.1 to 10 mol% of copper oxide (CuO) to the first powder, wet mixing, and drying to form a second powder; and
A method for producing a piezoelectric laminate actuator, characterized in that it comprises a step of sintering the second powder at 700 to 1000 ° C. to form a piezoelectric body.
[Formula 1]
(1-x) Pb (Zr 0 .47 Ti 0 .53) O 3 -xPb ((Ni 1 - y Zn y) 1/3 Nb 2/3) O 3
(Where x is 0.1 <x <0.5 and y is an integer of 0.1 <y ≦ 0.9). The method of manufacturing a piezoelectric body for a multilayer actuator according to claim 4, wherein x is 0.31 and y is an integer of 0.4. The method of claim 4, wherein in the preparing of the mixture, the raw powder is wet mixed with one solvent selected from the group consisting of methanol, ethanol, isopropanol and distilled water. 5. The method of claim 4, further comprising polishing the piezoelectric material prepared in the step of forming the piezoelectric material and applying an electrode material, followed by polling at DC 3 to 5 kV / mm in a silicon oil bath at 120 ° C. The manufacturing method of the piezoelectric body for laminated actuators which are used. 8. The method of claim 7, wherein the electrode material is one or a combination of two selected from the group consisting of silver (Ag), copper (Cu), palladium (Pd), and nickel (Ni). Way.

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