SU833836A1 - Piezoelectric ceramic material - Google Patents

Description

(54) PIEZOELECTRIC CERAMIC MATERIAL

The invention relates to radio engineering and can be used in the manufacture of converters operating at high temperature. Optically transparent single crystals grown from melts of alkaline-alkaline-earth niobates with the structure of css-tartar-tungsten bronze, possessing piezo-properties, as well as transparent ferroelectric ceramics based on alkaline-alkaline-earth nyobates with the structure of potassium-tungsten bronze, and piezoelectric ceramis in the form of a n-acte nyobate known as niobates with a potassium-tungsten-bronze structure, are known. dielectric constant (100–200), a high Curie point (580–620 ° C), maintaining piezo activity to a temperature 500–550 ° C, but not high piezo properties (piezomodule d is (9–12), the electromechanical coupling coefficient is Kp (0.1–0.2). The main drawback of such materials is high dielectric loss (0.001–0.002) and The firing temperature is rather high (1000-1300s). Ma Wa 5 71 Especially we will charge them - 20 25 30 and the most favorable to the proposed rial in the system (3-22 wt.%) - N65.05 (32 (18-60 wt.%) Ac.%) 2. Ezoceramic materials for this solid solutions of this solid solution for 4 hours at 1000-1050 ° C, crushed to pass through 10,000 spores / cm, after which the pre-preparation of the size mm mm iem 1,000 kg / cm2. Burn 1280-1300 ° С for 1-2 h, the following physical and chemical characteristics are observed: Density 10 kg / m 5.00-5.01 0.007-0.008 Water absorption,% Dielectric 111-129 permeability, g Tangent of dielectric loss angle, tg d Curie point, ° C 610-620 Piezomodul, d-lO, C / N Electromechanical coefficient 0.23-0.25 of communication, Cr

The material retains the piezoactivity up to C, the spread of values.

f (T).

uh

Said piezoceramic materials have relatively high first and second calcination temperatures and high dielectric loss tangent values.

The purpose of the invention is to reduce the firing temperature and dielectric loss while maintaining a high Curie point.

The goal is achieved by the fact that the known piezoelectric ceramic material, including, Ba O, N82.0, additionally contains LigO and the following ratio of components, wt.%:

51.7-69.8

N52% BaO 22.3-31.1 0.7-3.5

NajO 2.8-10.9

0.7-3.5

LijiO 1.0-2.0

Biio

The lithium, sodium and barium compounds are introduced into the mixture as anhydrous carbonates. The mixture is ground in an agate or corundum lining mill and with the same balls in an absolute alcohol medium.

After drying at 200-250 ° C, the material is subjected to the first firing in a powdered state at 850-900 ° C for 4 hours, then crushed to pass through a sieve of 10,000 holes / cm, and then pressed blanks of 14flO 2 mm under pressure of 1000 kg / cm2 . Secondary calcination takes place at 1090-1200 seconds for 1-2 hours.

Electrodes are applied by vacuum deposition of aluminum. The samples are polarized in silicon oil at a voltage of 1540 kV / cm for 8 hours with cooling under the field for 2 hours. Measurements are made after 1 day.

Example 1. Piezoelectric ceramic material composition, wt.%: Li / iO 1,6,; 3.3; BaO 24.7 Bi-jOj 1.1; NbjOj- 58.5; 10.8 obtained by the previously mentioned technology and has the following properties:

Synthesis temperature, ° С

Baking temperature, С

Density, kg / m Water absorption,% Dielectric permeability, 6 Tangent of dielectric loss angle, tg cf.

Curie point, C Piezomodul, lO-, Kl / N Electromechanical coupling coefficient Кр Material retains piezo activity up to, ° С The spread of values,

f (T),%.

Example 2. Piezoelectric ceramic material composition, wt.%: 2.2; NagO 1,2; BaO25.1 1.7; NbgOg- 59.0; TasOj-10.8 obtained by the above technology and has the following properties:

Synthesis temperature., Sintering temperature, Density, kg / m Water absorption,% Dielectric constant, 6 Tangences of dielectric loss angle, tgcf Curie point, C Piezomodul, .d3-i- 10, C / H Electromechanical coupling coefficient, Cr retains piezoactivity up to, ° C

 f (T),%

31

Example 3. Piezoelectric ceramic material composition, wt.%: L 1,0 0,7; 1.4; BAO 30.1; 2.0; Nb205- 63.0; 2.8 obtained by the above technology and has the following properties:

Synthesis temperature, C Sintering temperature, C Density, kg / m Water absorption,% Dielectric constant; The tangent of the angle of electric loss, tgcT Curie point, c Piezomodul, d 3 -10, C / H Electromechanical coupling coefficient, К р. The material retains piezoactivity up to, ° C. Scatter of values, d3i f (T),% 583383 claims Piezoelectric ceramic material, including BaO, NajO, characterized in that) in order to reduce the Roasting temperature and dielectric loss while maintaining a high Curie point, it additionally contains, and in the following ratio of components, wt.%: | MbOe 51.7-69.8 BaO 22.3-31.1 6 6 0.7-3.5 Ta Oy2.8-10.9 Lf O , 0.7-3.5 Bij-O l., 0-2; ft sources of information taken into account during the examination. 1. US patent No. 2805165, class; 252-629, publ. 1957. 2.-The author's certificate of the USSR 560409, cl. From 04 to 35/00, 1975.

Claims (2)

Claim The piezoelectric ceramic material, including Nb ^ Og ·, BaO, Na ₂ 0, is noteworthy in that, in order to reduce the firing temperature and dielectric loss while maintaining a high Curie point, it additionally contains Ta ^ O ^, Li ^ O and B ^{in the} following ratio of components, May.%: Nb ₂ 0 _? 51.7-69.8 Bao 22.3-31.1 Ma _r 0. 0.7-3.5 ^{T a} a ° 5 2.8-10.9 1 * - 0.7-3.5 In 1 * 0, 1,0-2; ft ' 5 Sources of information taken into account in the examination 1. US patent No. 2805165, ·. cells; 252-629, published. 1957. 2. Copyright certificate of the USSR No. 560409, cl. C 04 V 35/00, 1975.