KR19990056604A - Piezoelectric ceramic composition - Google Patents

Abstract

The present invention basically has a Samsung system represented by Pb (Sb _2/3 W _1/3 ) O ₃ -PbTiO ₃ -PbZrO ₃ , substitutes Sr and La at A site, and adds a small amount of MnO ₂ . The mechanical quality factor (Qm) and the electromechanical coupling factor (Kp) have high values and enable sintering at low temperatures, thereby providing a piezoelectric magnetic composition that can be widely used in piezoelectric transformers, actuators, ultrasonic vibrators, etc. will be.

Description

Piezoelectric ceramic composition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piezoelectric ceramic compositions, and to piezoelectric ceramic compositions having a high mechanical quality factor (Qm) and a high electromechanical coefficient (Kp) that can be used in piezoelectric transformers.

As a conventional piezoelectric ceramic composition, lead zirconate titanate (PZT) is widely known, but it does not completely exhibit various properties satisfying various electronic products. For this reason, the properties are realized by substituting various elements in the A site or B site of lead zirconate titanate (PZT), or the lead magnesium neobate (Pb (Mg _1/3 Nb _2/3 ) O ₃ ) ), Lead Manganese Nebate (Pb (Mn _1/2 Nb _2/3 ) O ₃ ), Lead Zinc Nebate (Pb (Zn _1/3 Nb _2/3 ) O ₃ ), Lead Nickel Nebate (Pb (Ni _A composition with addition of _1/3 Nb _2/3 ) O ₃ ) was used. However, since they have a high sintering temperature in common, there is a difficulty in manufacturing a stacked device, and there is a problem that it is difficult to realize stable characteristics due to volatilization of lead oxide (PbO).

The present invention has been drawn to solve the problems described above, and replace Sr, La at the A site of the Samsung system represented by Pb (Sb _2/3 W _1/3 ) O ₃ -PbTiO ₃ -PbZrO ₃ A small amount of MnO ₂ is added to provide a piezoelectric ceramic composition having a high mechanical quality factor (Qm) and an electromechanical coupling coefficient (Kp).

The present invention for achieving the above technical problem is αPb _1-x A _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (0.01≤α≤0.10mol%, 0.01≤x A piezoelectric ceramic composition composed of? 0.05 mol%, 0.4? Y? 0.5 mol%, 0.3? K? 1.0 wt%, and A = Sr, La).

The piezoelectric ceramic composition is substituted with Sr and La at the A site of the Samsung system represented by Pb (Sb _2/3 W _1/3 ) O ₃ -PbTiO ₃ -PbZrO ₃ , and a small amount of MnO ₂ is added to the piezoelectric transformer. It implements the required properties.

In general, when Pb (Sb _2/3 W _1/3 ) O ₃ is added to lead zirconate titanate (PZT), it has the advantage of low sintering temperature and high electromechanical coupling coefficient. The addition of manganese oxide (MnO ₂ ) not only improves the mechanical quality factor, but also has the advantage of high mechanical strength due to the small and dense particle size after sintering, which results in higher density. . In addition, when Sr is substituted for A site, the capacitance and mechanical quality factor are increased. If La is substituted for A site, the electromechanical coefficient increases.

An embodiment of the present invention will be described as follows.

Lead oxide (PbO), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), Sb ₂ O ₃ , WO ₃ , manganese oxide (MnO ₂ ), SrCO ₃ (or La ₂ O ₃ ) It is weighed to obtain the composition of the example, wet mixed and dried, and then calcined and ground at 800 to 1,000 ° C. for 2 hours. PVA (Poly Vinyl Alcohol) binder was added to the pulverized material, and then formed into a circular pellet having a diameter of 24 mm and a thickness of 1.5 mm, and sintered at 1100 ° C. for 2 hours. The silver (Ag) electrode is formed on both surfaces of the sintered body as described above, and a DC voltage of 2 to 3 kVmm is applied for 10 to 30 minutes in silicone oil, and then each method is used in the art. The density, electromechanical coupling factor (Kp), mechanical quality factor (Qm) and capacitance of the examples were measured and the results were obtained. As can be seen in the following <Example 2>, <Example 3>, <Example 7> and <Example 8>, the piezoelectric composition is applicable because it satisfies the characteristics required in the piezoelectric transformer.

<Example 1>

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.01mol%, y = 0.45mol%, z = 0.50mol %, k = 0.30wt%), the density was 7.63g / cm ³ , the electromechanical coefficient (Kp) was 56%, and the mechanical quality factor (Qm) was 895, dielectric constant (ε _r ) has a characteristic of 1250.

<Example 2>

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.02mol%, y = 0.45mol%, z = 0.50mol %, k = 0.50 wt%), the density was 7.79 g / cm ³ , the electromechanical coefficient (Kp) was 62%, and the mechanical quality factor (Qm) was obtained. The dielectric constant (ε _r ) is 1300 and the characteristic is 1430.

<Example 3>

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.04mol%, y = 0.45mol%, z = 0.50mol %, k = 0.70wt%), the density was 7.83g / cm ³ , the electromechanical coefficient (Kp) was 58%, and the mechanical quality factor (Qm) was 1430, dielectric constant (ε _r ) has a characteristic of 1720.

<Example 4>

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.05mol%, y = 0.45mol%, z = 0.50mol %, k = 1.00 wt%) was prepared by the above method to have a piezoelectric ceramic composition, the density is 7.89g / cm ³ , the electromechanical coefficient (Kp) is 48%, the mechanical quality factor (Qm) is 1050, dielectric constant (ε _r ) has a characteristic of 1690.

Example 5

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.10mol%, x = 0.01mol%, y = 0.45mol%, z = 0.45mol %, k = 0.50 wt%), the density was 7.78 g / cm ³ , the electromechanical coefficient (Kp) was 51%, and the mechanical quality factor (Qm) was obtained. 1270, dielectric constant (ε _r ) has a characteristic of 980.

<Example 6>

αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.10mol%, x = 0.02mol%, y = 0.45mol%, z = 0.45mol %, k = 1.00 wt%) to have a piezoelectric ceramic composition composed of the above method, the density is 7.85g / cm ³ , the electromechanical coefficient (Kp) 53%, the mechanical quality factor (Qm) is The dielectric constant (ε _r ) is 1100 and 1050.

<Example 7>

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.01mol%, y = 0.45mol%, z = 0.50mol %, k = 0.50wt%), the density was 7.75 g / cm ³ , the electromechanical coefficient (Kp) was 62%, and the mechanical quality factor (Qm) was 1450, dielectric constant (ε _r ) has a characteristic of 1300.

<Example 8>

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.02mol%, y = 0.45mol%, z = 0.50mol %, k = 0.50 wt%), the density was 7.70 g / cm ³ , the electromechanical coefficient (Kp) was 59%, and the mechanical quality factor (Qm) was obtained. 1430, dielectric constant (ε _r ) has a characteristic of 1545.

Example 9

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.04mol%, y = 0.45mol%, z = 0.50mol %, k = 0.70 wt%), the density was 7.91 g / cm ³ , the electromechanical coefficient (Kp) was 53%, and the mechanical quality factor (Qm) was 1200, dielectric constant (ε _r ) has a characteristic of 1320.

<Example 10>

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.05mol%, x = 0.05mol%, y = 0.45mol%, z = 0.50mol %, k = 1.00 wt%) was prepared by the above method to have a piezoelectric ceramic composition, the density is 7.85g / cm ³ , the electromechanical coefficient (Kp) is 45%, the mechanical quality factor (Qm) is The dielectric constant (ε _r ) was 1000 and 1150.

<Example 11>

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.10mol%, x = 0.02mol%, y = 0.45mol%, z = 0.45mol %, k = 0.50 wt%), the density was 7.74 g / cm ³ , the electromechanical coefficient (Kp) was 52%, and the mechanical quality factor (Qm) was 1370, dielectric constant (ε _r ) has a characteristic of 1060.

<Example 12>

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.10mol%, x = 0.04mol%, y = 0.45mol%, z = 0.45mol %, k = 0.70wt%), the density was 7.82g / cm ³ , the electromechanical coefficient (Kp) was 49%, and the mechanical quality factor (Qm) was The dielectric constant (ε _r ) is 1100 and the characteristic is 1100.

Example 13

αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ (α = 0.10mol%, x = 0.05mol%, y = 0.45mol%, z = 0.45mol %, k = 1.00 wt%) was prepared by the above method to have a piezoelectric ceramic composition, the density is 7.78g / cm ³ , the electromechanical coefficient (Kp) is 45%, the mechanical quality factor (Qm) is 975, dielectric constant (ε _r ) has a characteristic of 1125.

Example mol% k (wt%) Density (g / cm ³ ) Electromechanical Coupling Factor Kp (%) Mechanical Quality Factor Q _m ε _r α x y z One 0.05 0.01 0.45 0.50 0.30 7.63 66 895 1250 2 0.05 0.02 0.45 0.50 0.50 7.79 62 1300 1430 3 0.05 0.04 0.45 0.50 0.70 7.83 58 1400 1720 4 0.05 0.05 0.45 0.50 1.00 7.89 48 1050 1690 5 0.10 0.01 0.45 0.45 0.50 7.78 51 1270 980 6 0.10 0.02 0.45 0.45 1.00 7.85 53 1100 1050 7 0.05 0.01 0.45 0.50 0.50 7.75 62 1450 1300 8 0.05 0.02 0.45 0.50 0.50 7.70 59 1430 1545 9 0.05 0.04 0.45 0.50 0.70 7.91 53 1200 1320 10 0.05 0.05 0.45 0.50 1.00 7.85 45 1000 1150 11 0.10 0.02 0.455 0.45 0.50 7.74 52 1370 1060 12 0.10 0.04 0.45 0.45 0.70 7.82 49 1100 1100 13 0.10 0.05 0.45 0.45 1.00 7.78 45 975 1125

The piezoelectric composition according to the present invention has a high electromechanical coupling factor (Kp) and a mechanical quality factor (Qm), and can be sintered at low temperatures, thereby enabling applications of piezoelectric transformers, actuators, and ultrasonic vibrators. Do.

Claims (2)

A piezoelectric ceramic composition, wherein the composition component and the ratio are represented by the following formula. αPb _1-x Sr _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ In the above, 0.01≤α≤0.10mol%, 0.01≤x≤0.05mol%, 0.4≤y≤0.5mol%, 0.3≤k≤1.0wt%. A piezoelectric ceramic composition, wherein the composition component and the ratio are represented by the following formula. αPb _1-x La _x (Sb _2/3 W _1/3 ) O ₃ -yPbTiO ₃ -zPbZrO ₃ + kMnO ₂ In the above, 0.01≤α≤0.10mol%, 0.01≤x≤0.05mol%, 0.4≤y≤0.5mol%, 0.3≤k≤1.0wt%.