Piezoelectric ceramic material

FIELD: chemistry.

SUBSTANCE: piezoceramic material based on a solid solution system aNaNbO3+bKNbO3+cCuNb2O6 (a+b+c=100%) contains sodium, potassium, niobium and copper oxides, with the following ratio of components, wt %: Na2O 13.87-14.87; K2O 4.24-5.62; Nb2O5 79.32-79.70; CuO 1.19. The material is characterised by high relative permittivity ( ε З З T / ε 0 = 300 ) , while maintaining a sufficiently high mechanical Q-factor (Qm=1050) and piezoelectric properties. This is possible owing to formation, during sintering, of intermediate Cu-containing compounds with a low melting point, with which formation of liquid phases is associated, where said liquid phases enable to form an improved microcrystalline (granular) structure.

EFFECT: improved characteristics.

2 tbl

 

The invention relates to piezoelectric ceramic materials based on sodium niobate and can be used in power and RF ultrasonic devices, in particular ultrasonic piezophiles and industrial shredders.

For these applications, piezoelectric ceramic material should have high values of the mechanical quality factor, Qm, (more than 1000), the Electromechanical coupling coefficient of the planar oscillation modes, Kp(over 0.15), piezoelectric coefficient d33(more than 50), the piezoelectric coefficient |d31| (over 10), relative dielectric constant,ε33Tε0, (300 to 500).

Known piezoelectric ceramic material based on barium titanate, comprising the oxides of HLW, ILW, TiO2, SnO, ZrO. The material is for the best structures of Qm=1126, |d31|=61.1 PC/N [1].

This material has a low value of the Curie temperature (TWith=110°C), making it unsuitable for these applications.

Known piezoelectric ceramic material based on sodium niobate, including carbonates of Na2CO3, K2CO3Li2CO3and oxides of Nb2O Bi2O3, TiO2. The material is for the best structures ofε33Tε0=717, d33=80 PC/N, Kp=0.24,2, Qm=88 [2].

For these applications the material has a too low Qm values.

Known piezoelectric ceramic material based on sodium niobate, comprising the oxides of K2O, Na2O, Nb2O5, CdO. The material hasε33Tε0=1360Top=0.12, |d31|=28 PC/N, Qm=1000 [3].

For these applications the material has a high enough value of Kpand too large a value ofε33Tε0.

The closest to the claimed material according to technical essence and the achieved result is a piezoelectric ceramic material based on sodium niobate, including carbonates of Na2CO3, K2CO3and oxides of Nb2O5, CuO. The material has a Qm=1408.2, |d31|=29.2 PC/N, d33=96.2 PC/N, Ksub> p=0.389,ε33Tε0=237[4] (prototype).

For these applications the material has a high enough valueε33Tε0and too large a value of Qm.

The object of the invention is to increase the relative dielectric constant toε33Tε0=300while maintaining sufficiently high values of Qm, Kp, d33, |d31|. The material shall be obtained by conventional ceramic technology that allows mass production.

These results are achieved by the fact that the piezoelectric ceramic material based on sodium niobate, including Na2O, K2O, Nb2O5, CuO in the following ratio of components, wt.%:

Na2O 13.87-14.87

K2O 4.24-5.62

Nb2O579.32-79.70

CuO 1.19-1.19.

The composition of the material corresponds to the formula:

aNaNbO3+bKNbO3+cCuNb2O6where a=75.00-8000 (mol. %), b=15.00-20.00 (in mol. %), with a=2.5 (mol. %), a+b+C=100%.

Introduction to the material on the basis of Na2O, K2O and Nb2O5copper oxide CuO leads to the formation during sintering of the intermediate Cu-containing compounds, in particular, K4CuNb8O23with low melting temperature (1050°C [5]), which is associated with the formation of liquid phases, contributing to the formation of more advanced micro-crystalline (grain) structure. With an increase in the average size of crystallites (in the formation of a more perfect microcrystalline structure) reduces the area of grain boundaries, which are centers of pining domain walls. It promotes the growth ofε33Tε0.

In table.1 shows the values of electrophysical parameters of the piezoelectric ceramic material depending on the composition.

In table.2 shows comparative electrophysical parameters of the prototype and the optimal composition of the inventive piezoelectric ceramic material.

As initial reagents were used oxides of the following qualifications: K2O - "h", Na2O - "C. D. A.", Nb2O5- "TBO-Fri, CuO - "chemically pure".

Piezoelectric ceramic material and�be compiled by a conventional ceramic technique as follows. The synthesis is carried out by means of a single firing mixtures previously obtained niobates NaNbO3and KNbO3and columbite CuNb2O6. As initial reagents were oxides, wt.%: Na2O 13.87-14.87, K2O 4.24-5.62, Nb2O579.32-79.70, CuO 1.19-1.19. Firing temperature TSint.=(750-1050)°C, duration isothermally τ=5 h. the Sintered samples in the form of columns ⌀12 mm, height 15÷18 mm is carried out at TSP.=(1050-1130)°C, the duration of isothermal holding τ=2 h. the Metallization (applying electrodes) is made by coating the flat surface of the pre-zashlifovannym to a thickness of 1 mm samples containing silver paste and its subsequent brazing at a temperature Twig.=1070 K for 0.5 h. the Samples polarize in polyethyleneoxide liquid at a temperature of 410 K for 40 min in a constant electric field of 3 kV/cm.

In accordance with OST 11.0444-87 was determined electrical characteristics: relative permittivity polarized(ε33Tε0)samples, pesumably - (|d31for | and d33), the Electromechanical coupling coefficient of a planar fashion �of Albany (K p), mechanical quality factor (Qm).

The obtained experimental data (table.1, examples 2-4) indicate that the piezoelectric ceramic material of the proposed composition has a combination of electro-physical parameters corresponding to the invention (300<ε33Tε0, d33≥50 PC/N, |d31|≥10 PC/N, Kp>0.15, Qm>1000). Going beyond the stated concentrations of the components leads to a significant reduction of the target parameters, in particular, Qm,ε33Tε0and Kp.

The data given in table.2, confirm the benefits proposed piezoelectric ceramic material compared with the material - the prototype, namely the increase ofε33Tε0mwhile maintaining high values of Qm, Kp, d33and |d31|, 1050, 0.17, 50 PC/N and 15 PC/N, respectively.

The effect of increasing elektrofizicheskie� is achieved essentially an introduction to the material, including Na2O, K2O and Nb2O5a larger amount of copper oxide CuO.

High values ofε33Tε0, Qmand Kpmaterial determine its main purpose is use in power and high-frequency ultrasonic devices, in particular in the ultrasonic piezophiles and industrial shredders.

Subject to the approval of the Converter to the load (Ri=RH) (usually implemented in a commercially available electronic equipment output resistance RH~ 50 Ω for high frequencies), using the formula for capacitive impedance Converter: Ri=1/ωC, where Ri- capacitance Converter (Ω); ω - circular frequency, Hz; C - capacitance, f; can roughly estimate the range of values of capacitance C=1/2πfRifor the specified ranges of frequencies, and, consequently, the relative dielectric constant of the polarized elements ofε33Tεm=kCwhere k - coefficient depending on the size of elements, ε0=8.85·1 -12F is the permittivity of vacuum; for k=1,ε33Tε0=C. Thus, increasing values ofε33Tε0allows to reduce the operating frequency of the target ultrasonic devices for their more efficient use.

Sources of information

1. US 2013/0278681 A1, IPC G02B 27/00, H01l 41/43, H01l 41/047, publication date 24.10.2013.

2. CN 102180670 (A), IPC SW 35/495, SW 35/622, publication date 14.09.2011.

3. EN 2498960, IPC SW 35/49, publication date 20.11.2013.

4. EP 1032057(A1), IPC H01L 41/187, publication date 23.02.2000.

5. Matsubara, M., Yamaguchi, T., Sakamoto, W., Kikuta K., Yogo, T., Hirano, S.-I. Processing and Piezoelectric Properties of Lead-Free (K, Na) (Nb, Ta) O3Ceramics // J. Am. Ceram. Soc. 2005. V. 88. No. 5. P. 1190-1196.

Table 1
The dependence of electrophysical parameters of the inventive piezoelectric ceramic material between the concentration of components
№ p/pComposition, wt.%E�astrofizicheskie
Na2OK2ONb2O5CuOε33T/ε0KpQmd33, PC/N|d31|, PC/N
113.386.3179.131.182600.148754512
213.875.6279.321.193000.1710505013
314.374.9379.511.193050.171045 5314
414.874.2479.71.193000.1610305013
515.373.5379.91.22800.15903510

Table 2

Piezoelectric ceramic material containing Na2O, K2O, Nb2O5, characterized in that it further comprises CuO in the following ratio of components, wt.%:
Na2O 13,87-14,07
K2O 5,34-to 5.62
Nb2O579,32-our 79.40
CuO 1,19
or
Na2O 14,47-14,87
K2O a 4.24 4,79
Nb2O579,55-79,70
CuO 1,19.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: piezoelectric ceramic material contains the following components, wt %: Na2O 9.41-9.51; K2O 12.25-12.42; CdO 0.75-1.12; Nb2O5 77.22-77.32.

EFFECT: low relative permittivity and mechanical Q factor, high piezoelectric sensitivity, electromechanical coupling factor of the planar oscillation mode and speed of sound.

3 ex, 3 tbl

FIELD: chemistry.

SUBSTANCE: piezoelectric ceramic material contains the following components, wt %: Na2O 8.61-8.70; K2O 11.15-11.26; Li2O 0.49-0.50; Ta2O5 11.37-11.49; Nb2O3 61.59-62.19; Bi2O3 0.37-1.10; Fe2O3 0.13-0.38; Sb2O5 5.31-5.37.

EFFECT: high electromechanical coupling factor of the planar oscillation mode and low relative permittivity.

3 ex, 3 tbl

FIELD: chemistry.

SUBSTANCE: piezoelectric ceramic material contains the following elements, wt %: Na2O 8.77-8.84; K2O 11.36-11.44; Li2O 0.32-0.33; Ta2O5 11.58-11.67; Sb2O5 3.53-3.56; Nb2O5 62.71-63.17; NiO 0.99-1.73.

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3 tbl, 3 ex

FIELD: chemistry.

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2 ex, 3 tbl

FIELD: chemistry.

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EFFECT: high mobility of domain walls and, as a result, high permittivity ε33 Tε0, piezoelectric modulus d33, hydrostatic piezoelectric modulus dh and hydrostatic Q-factor dh·gh, and low mechanical Q-factor Qm due to higher internal friction with high mobility of domain walls.

2 tbl

FIELD: construction.

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EFFECT: creation of morphotropic structure at the border of material phase interface having improved piezoelectric properties.

13 cl

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4 tbl

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2 tbl, 2 ex

FIELD: chemistry.

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2 ex, 2 tbl

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8 cl, 10 ex

FIELD: chemistry.

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2 tbl

FIELD: chemistry.

SUBSTANCE: piezoelectric ceramic material contains the following components, wt %: Na2O 9.41-9.51; K2O 12.25-12.42; CdO 0.75-1.12; Nb2O5 77.22-77.32.

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3 ex, 3 tbl

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EFFECT: high electromechanical coupling factor of the planar oscillation mode and low relative permittivity.

3 ex, 3 tbl

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EFFECT: low mechanical Q factor, relative permittivity of polarised samples, high piezoelectric modulus, piezoelectric sensitivity, specific sensitivity and electromechanical coupling factor of the planar oscillation mode.

3 tbl, 3 ex

FIELD: chemistry.

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EFFECT: low mechanical Q-factor, high piezoelectric modulus, piezoelectric sensitivity, specific sensitivity and electromechanical coupling factor.

3 ex, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to piezoelectric ceramic materials based on sodium niobate and can be used in making low-frequency receivers - hydrophones, microphones, hydro receivers, as well as in making low-frequency electromechanical transducers, which excite metallic resonators with high sound speed. The piezoelectric ceramic material contains sodium, potassium, cadmium and niobium oxides, with the following ratio of components, wt %: Na2O 8.75-9.72, K2O 5.31-5.38, CdO 9.15-10.88, Nb2O5 75.05-75.77. The material is produced using conventional ceramic processing.

EFFECT: material has high relative permittivity of polarised samples, sound speed and mechanical Q-factor.

3 ex, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to production of piezoelectric ceramic materials and can be used in making high-frequency electromechanical transducers particularly used in ultrasonic delay lines (used in the 20-30 MHz range), highly sensitive single-response crystals operating on thickness vibrations; in devices where weight characteristics are decisive. The piezoelectric ceramic material based on sodium niobate contains sodium, niobium, lithium, strontium, aluminium and manganese oxides, with the following ratio of components, wt %: Na2O 16.28-16.50, Nb2O5 79.61-80.71, Li2O 1.12-1.14, SrO 0.63-0.64, Al2O3 0.31-0.32, MnO2 0.69-2.05. The material is produced using conventional ceramic processing. The firing temperature during synthesis is equal to 1133 K.

EFFECT: material has low relative permittivity of polarised samples, high piezoelectric sensitivity on the thickness vibration mode, sufficiently high mechanical Q-factor, as well as high sound speed, low density and high piezo-anisotropy.

3 ex, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in manufacturing organic light-emitting diodes, liquid-crystal displays, plasma display panel, thin-film solar cell and other electronic and semi-conductor devices. Claimed is element, including target of ionic dispersion, where said target includes processed MoO2 plate of high purity. Method of such plate manufacturing includes isostatic pressing of component consisting of more than 99% of stoichiometric MoO2 powder into workpiece, sintering of said workpiece under conditions of supporting more than 99% of MoO2 stoichiometry and formation of plate which includes more than 99% of stoichiometric MoO2. In other version of said plate manufacturing component, consisting of powder, which contains more than 99% of stoichiometric MoO2, is processed under conditions of hot pressing with formation of plate. Method of thin film manufacturing includes stages of sputtering of plate, which contains more than 99% of stoichiometric MoO2, removal of MoO2 molecules from plate and application of MoO2 molecules on substrate. Also claimed is MoO2 powder and method of said plate sputtering with application of magnetron sputtering, pulse laser sputtering, ionic-beam sputtering, triode sputtering and their combination.

EFFECT: invention allows to increase work of output of electron of ionic sputtering target material in organic light-emitting diodes.

16 cl, 5 ex

FIELD: chemistry.

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EFFECT: improved mechanical properties and chemical stability of the material.

8 cl, 1 ex

FIELD: construction.

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EFFECT: lower level of vibration noises due to increased ratio of pyrocoefficient to piezomodule.

1 tbl

FIELD: chemistry.

SUBSTANCE: present invention can be used in devices for defectoscopy of equipment of atomic reactors, working at high temperatures. The piezoelectric ceramic material based on lithium metaniobate contains oxides of lithium, niobium and strontium at the following ratio of components, wt %: Li2O - 9.02÷9.17; Nb2O5 - 86.27÷86.77; SrO - 4.71÷4.06. The material is made using traditional ceramic processing technology.

EFFECT: attaining upper limit of working temperature, electromechanical coupling coefficient of the width of oscillation mode, piezoelectric modulus; ratio of electromechanical coupling coefficient of the width and planar oscillation mode and piezoelectric modulus approach infinity, which enables suppression of parasitic oscillations, distorting the operational signal.

2 ex, 2 tbl

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