JPH0959060A - Piezoelectric porcelain composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a piezoelectric porcelain material having a low inner energy loss and capable of being driven at high vibration level. SOLUTION: This porcelain composition consists of three components of Pb(Mg1/3 Nb2/3 )O3 , Pb(Mn1/3 Sb2/3 )O3 and PbTiO3 , and has composition ratios expressed by the slant lined part. Than is, when the composition is expressed by the formula [(Pb(Mg1/3 Nb2/3 )O3 ]x [Pb(Mn1/3 Sb2/3 )O3 ]y [PbTiO3 ]z (x+y+z=1), the porcelain composition exists inside the quadrilateral formed by connecting the four points of the following A, B, C and D in a three-component composition diagram. A: (x=0.01, y=0.75, z=0.42). B: (x=0.01, v=0.71, z=0.28). C: (x=0.15, v=0.43, z=0.42). D: (x=0.15, v=0.57, z=0.28).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric ceramic composition, and more particularly to a piezoelectric ceramic composition capable of driving a high vibration level or a large amplitude.

[0002]

2. Description of the Related Art Piezoelectric materials capable of converting electrical energy into mechanical vibration energy have been applied to the field of power such as piezoelectric actuators and ultrasonic motors. Due to the extremely high mechanical output required for these applications, the piezoelectric material will be driven with large amplitude or high vibration levels. Therefore, for these applications, piezoelectric materials can be suppressed from increasing internal energy loss even when driven at high vibration levels:
It is required to have limits at high vibration levels.

Heretofore, lead-based composite perovskite compounds have been widely known as piezoelectric ceramic compositions, and some compositions have been put to practical use. Among them, lead magnesium niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ] are two typical composition materials suitable for large-amplitude driving because of their large dielectric constant. Component compound (hereinafter PMN-PT
However, this material increases heat generation due to internal energy loss as the operating vibration level increases,
Eventually dielectric breakdown of the material occurs.

Here, it is assumed that the vibration level is given by an effective vibration velocity v ₀ which can be calculated from the measurement of the maximum tip amplitude ξ _m of the vibrator and the resonance frequency f ₀ of the vibrator obtained from the optical displacement measuring device. To do. v ₀ can be expressed by the following equation. v ₀ = (√2) πf ₀ ξ _m (1) When the vibration level is expressed by the vibration speed in this way, the limit of the vibration level (speed) that can be stably used in the conventional material is 0.1 m / s. It stayed.

[0005]

Since the conventional PMN-PT material is limited to driving at a low vibration level (speed) with an upper limit of about 0.1 m / s, a large mechanical output is required. Application to power devices was difficult. Further, various measures were taken to increase the output of PMN-PT, but the effect of improving the material performance was not found.

In the present invention, the vibration level (speed) limit v _0max , which has been difficult in the past, becomes three times or more than that in the conventional v _0max ≧
It was made for the purpose of providing a piezoelectric ceramic composition having a characteristic of 0.3 m / s.

[0007]

The piezoelectric ceramic composition according to the present invention for achieving the above object is a lead magnesium niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], manganese antimony. It is composed of three components, lead acid [Pb (Mn _1/3 Sb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ], and particularly magnesium lead niobate [Pb (Mg
_1/3 Nb _2/3 ) O ₃ ], manganese / lead antimonate [P
b (Mn _1/3 Sb _2/3 ) O ₃ ] and lead titanate [Pb
A three-component composition consisting of [TiO ₃ ] [Pb (Mg _1/3 N
b _2/3 ) O ₃ ] _x [Pb (Mn _1/3 Sb _2/3 ) O ₃ ] _y
When expressed as [PbTiO ₃ ] _z (however, x + y + z = 1), in the three-component composition diagram of this three-component composition, the following four points A, B, C and D, A: (x = 0.01 , Y = 0.57, z = 0.42) B: (x = 0.01, y = 0.71, z = 0.28) C: (x = 0.15, y = 0.43, z = 0.42) D: of the composition ratio defined by the points on the line connecting (x = 0.15, y = 0.57, z = 0.28) and the points included in the quadrangle formed thereby. It is a thing.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. The piezoelectric ceramic composition according to the present invention is a lead magnesium niobate [Pb (Mg _1/3 Nb
_2/3 ) O ₃ ], manganese / lead antimonate [Pb (Mn
_1/3 Sb _2/3 ) O ₃ ] and lead titanate [PbTiO 3
_[3 ]] and is a porcelain composition having a perovskite structure.

The preferable composition ratio is shown by the hatched portion in the three-component composition diagram of FIG. That is, lead magnesium niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], lead manganese antimonate [Pb (Mn _1/3 Sb _2/3 ) O
₃ ] and lead titanate [PbTiO ₃ ] are added to the three-component composition [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] _x [Pb
When expressed as (Mn _1/3 Sb _2/3 ) O ₃ ] _y [PbTiO ₃ ] _z (where x + y + z = 1), in the three-component composition diagram of this three-component composition, the following A, B, C , D 4
Point, A: (x = 0.01, y = 0.57, z = 0.42) B: (x = 0.01, y = 0.71, z = 0.28) C: (x = 0 .15, y = 0.43, z = 0.42) D: a point on a line connecting (x = 0.15, y = 0.57, z = 0.28) and a quadrangle formed thereby. The composition ratio is determined by the points included in.

[0010]

Next, an embodiment of the present invention will be described. As starting materials for obtaining the material of the present invention, lead oxide (PbO), titanium oxide (TiO ₂ ), magnesium oxide (MgO),
Niobium oxide (Nb ₂ O ₅ ) and manganese carbonate (Mn
CO ₃ ) and antimony oxide (Sb ₂ O ₃ ) powders were used. Here, MnCO ₃ was converted to MnO to obtain the required amount.

A predetermined amount of each raw material powder was weighed for each example, wet-mixed with a ball mill, and the mixed powder was 850 ° C. for 2 minutes.
h, calcined in the atmosphere. After calcination of the calcined powder, granulation and molding, firing at 1200 ° C. for 2 hours in the air, length 6
A sintered block having a width of 0 mm, a width of 30 mm and a thickness of 10 mm was obtained. 43 × 7 × 1mm by cutting and polishing this block
After processing into a rectangular plate of ^t , silver electrodes were baked on both main surfaces facing each other, and a direct current electric field of 4 kV / mm was applied in insulating oil at 100 ° C. for 1 hour to perform polarization treatment.

After being left at room temperature for 24 hours, a constant current drive circuit excites the basic mode of piezoelectric transverse effect length longitudinal vibration.
The vibration level limit was measured. The vibration level was obtained by the effective vibration velocity v ₀ that can be calculated from the measurement of the maximum tip vibration amplitude ξ _m of the vibrator and the resonance frequency f ₀ of the vibrator obtained from the optical displacement measuring device. v ₀ = (√2) πf ₀ ξ _m (1) The vibration level (velocity) limit is the temperature rise (vibrator temperature and room temperature) measured by measuring the temperature of a thermocouple installed at the vibration node of the piezoelectric vibrator. Difference) ΔT is 20 ° C
_It was expressed as _0max, and this was set as the vibration level limit. Table 1 and Table 2 show the composition ratio and vibration level limit of each example.

[0013]

[Table 1]

FIG. 2 shows the correlation between the vibration level (speed) and the temperature increase ΔT in the embodiment of the present invention. In the example of the present invention, the temperature rise remains at about 10 ° C. even when the vibration level reaches 0.3 m / s, and the temperature rise is gentle even if it exceeds this range.

[0015]

[Table 2]

[Comparative Example] For comparison, the present invention was conducted using only lead oxide (PbO), titanium oxide (TiO ₂ ), magnesium oxide (MgO) and niobium oxide (Nb ₂ O ₅ ) powders as starting materials. A similar device was formed by the same method as in the above example. The obtained device was measured in the same manner as in the example, and the results shown in Table 3 were obtained. Further, the correlation between the vibration level (speed) and the temperature increase ΔT in the comparative example is shown in FIG.

[0017]

[Table 3]

From the comparison between Table 3 and Table 1 and Table 2, PMN-PT of the conventional example was prepared according to the present invention with Pb (Mn _1/3 Sb).
It can be seen that the vibration level limit is more than tripled by adding _2/3 ) O ₃ . Further, as shown in FIG. 2, the vibration level (speed) of the conventional material is 0.05 m /
When it exceeds s, a rapid temperature rise occurs and the vibration level cannot be increased to 0.1 m / s or more. This is because even if electric power is applied to the vibrator in order to make it have a large amplitude, heat dissipation is increased due to internal energy loss of the vibrator, and there is a high risk of thermal destruction. On the other hand, since the composition according to the present invention has a small internal energy loss, the applied power is converted into vibration energy with high efficiency and can be driven at a high vibration level.

[0019]

As described above, the porcelain composition according to the present invention composed of the three components magnesium lead niobate, manganese lead antimonate, and lead titanate has a small internal energy loss, and therefore has a high vibration. It becomes possible to drive at the level. Therefore, according to the present invention, it is possible to provide an excellent material for manufacturing a power piezoelectric device driven at a high vibration level or a large amplitude.

[Brief description of drawings]

FIG. 1 is a three-component composition diagram for explaining an embodiment of the present invention.

FIG. 2 is a graph showing vibration level-temperature rise characteristics of an element manufactured using the material of the example of the present invention and an element using the conventional example material.

Claims (2)

[Claims] 1. Magnesium lead niobate [Pb (Mg
_1/3 Nb _2/3 ) O ₃ ], manganese / lead antimonate [P
b (Mn _1/3 Sb _2/3 ) O ₃ ] and lead titanate [Pb
TiO ₃ ], a piezoelectric ceramic composition comprising three components. 2. Magnesium lead niobate [Pb (Mg
_1/3 Nb _2/3 ) O ₃ ], manganese / lead antimonate [P
b (Mn _1/3 Sb _2/3 ) O ₃ ] and lead titanate [Pb
A three-component composition consisting of [TiO ₃ ] [Pb (Mg _1/3 N
b _2/3 ) O ₃ ] _x [Pb (Mn _1/3 Sb _2/3 ) O ₃ ] _y
When expressed as [PbTiO ₃ ] _z (however, x + y + z = 1), in the three-component composition diagram of this composition, the following A,
4 points of B, C, and D, A: (x = 0.01, y = 0.57, z = 0.42) B: (x = 0.01, y = 0.71, z = 0.28) ) C: (x = 0.15, y = 0.43, z = 0.42) D: (x = 0.15, y = 0.57, z = 0.28) A point on the line connecting this and this A piezoelectric porcelain composition having a composition ratio defined by points contained in a quadrangle formed by.