SU897759A1 - Method of producing piezoceramic materials based on lead zirconate-titanate - Google Patents

Description

(METHOD FOR OBTAINING PIECO-CERAMIC MATERIALS BASED ON LEAD CIRCONATATE TITANATE

I

The invention relates to methods for producing piezoceramic materials doped with Zn, Bi, Mn or Zn, Bi, Mn, Sr solid solutions of lead zirconate titanate (PZT) used in piezoelectric engineering.

A method is known for producing Zn, Bi, Mn or Zn, Bi, Mn, Sr alloyed solid solutions of lead zirconato-titanate, which consists in mixing powdered lead carbonate with oxides of titanium, zirconium and alloying metals, followed by calcining the resulting mixture during grinding and sintering the finished product 1 and 2.

Ceramics from powders prepared in this way are sintered at high temperature (1100 + 20 ° C), while it has low values of electro-mechanical coupling coefficients (0.25 - 0.42).

The closest in technical essence and the achieved result

is a method for producing PTS-based piezoceramic materials by calcining a mixture prepared by precipitating from aqueous solutions of lead compounds and alloying additives on the solid phase of titanium and zirconium compounds at pH 8.5. A mixture of solutions of concentrated ammonia (20-25%) and ammonium carbonate in the ratio of 1: 8-1: 10 is used as a precipitant according to this method.

3

The disadvantage of this method is the low values of the electrophysical parameters.

15

The purpose of the invention is to increase the electromechanical coupling coefficient of ceramics while maintaining the stability of the remaining electrophysical parameters of lead zirconate titanate

20 Zn, Bi, Mn or Zn, Bi, Mn, Sr.

This goal is achieved in that according to the method of producing piezoceramic materials based on lead zirconate titanate, precipitating lead compounds and alloying metals with ammonium carbonate from solutions of their salts onto powdered zirconium and titanium compounds followed by calcining the grinding and sintering the precipitation is carried out at pH 7 , 8 - 8.2. In addition, precipitation leads to crystal-like carbonized titanium hydroxide and basic zirconium carbonate, previously dried in a thin layer at 80 - When the pH deviates from the indicated limits during the precipitation of all components of the components, the precipitation of alloying metals is not achieved, which leads to a shift in the chemical composition materials. A sharp is observed. deterioration of the value of the electromechanical coupling coefficient. When replacing titanium and zirconium oxide (ferrous raw materials for oxides or other compounds or for heat treatment conditions), the sintering temperature of ceramics increases by 170 - 250 Example. In the precipitator equipped with an agitator, the calculated volumes of solutions of nitrate salts are poured. Before introducing bismuth nitrate to avoid its hydrolysis is added with 1.32 l of nitric acid (d 1.35). Then, crystal-like carbonized hydroxide, tannane and basic zirconium carbonate are loaded into the reactor. The mixture is stirred for 30–0 minutes, and then an ammonium carbonate solution is added at a rate of 15–20 l / h to a pH of 7.8–8.2. The suspension is kept under stirring for 2–3 hours. After that, the precipitate is separated on the NUTCH filter from the mother liquor and calcined in the form of a paste for 5 hours. The synthesized powders are subjected to vibratory milling to a total specific surface of 7 / A500 cm / g, after which they are sintered in the form of 020 x 1 mm discs and the electrophysical properties are measured. The volumes of solutions of nitric acid salts and the amount of powdered compounds to obtain 20 kg of piezoceramic materials based on doped solid solutions of lead zirconate titanate are presented in Table. 1 and 2 respectively. In tab. Figure 3 shows the values of the electromechanical coupling coefficient (Kp) of the material as a function of pH during the precipitation stage. In tab. Figure 4 shows the dependence of the sintering temperature of powders from doped lead zirconate titanate on the titanium and zirconium raw materials used. In tab. 5 shows the electrophysical properties of ceramics made from alloyed solid solutions of PZT. The proposed method allows reducing the sintering temperature of ceramics to 930 4 20 ° С, increasing the values of the electromechanical coupling coefficient to 0.5 (for PZT-35) to 0.32 (for PZT-3 and for PZT-33) while maintaining high stability all other parameters. Table 1

Lead nitrate

Strontium nitrate

56,36

56.09

Claims (3)

1.51 Manganese nitrate Zinc nitrate Bismuth nitrate TsTS-35 TsTS-3 TsTS-33 Carbonized titanium hydroxide Basic zirconium carbonate Continued tabl, 1 3J7 3.17 5.61 5.61 1.81 1.83 table 2 , 31 C, C 3.77 6.52 6.39 7.56 0.98 (Pbo) 9 To SO, - 0.02Zr {B1i, 5 Нп, Д) 0 0.98 (-1 SI ° 5- 0.02Zr () 0, 0.98Pb (Znj, 2 0% 0.02Zr ( 0.92. 0.330 0.331 0.507 0, + 96 0.326 0.489 0.319 0.328 0.507 0.378 0.250 0, 0.365 0, 0.230 Basic zirconium carbonate after spray drying Dioxide titanium TC Anatase Zirconia Basic zirconium carbonate after spray drying Basic zirconium carbonate, dried at B-120 in a thin layer Continuation of table 3 The solution in solution is manganese, bismuth and zinc ions (the latter in significant quantities). Table k For 1100 + 20 1100 + 20 930 + 20 Foomul of the Invention 1. A method for producing piezoceramic materials based on lead zirconato-titanate by precipitating lead compounds and ammonium carbonates from ammonium carbonate with ammonium carbonate from a solution of their salts onto a powder-like compound of titanium and zirconium followed by calcination, grinding and sintering operations, , in order to increase the electromechanical coupling coefficient while maintaining the stability of other electrophysical parameters of lead zirconate-titanate doped with zinc, bismuth, manganese or zinc com, bismuth, manganese or strontium, precipitation is carried out at a pH of 7.8-8.2. Table 5 2. The method according to claim 1, characterized by the fact that, in order to reduce the sintering temperature, the precipitation leads to crystal-like carbonized titanium hydroxide and basic zirconium carbonate, previously dried in a thin layer with . 8P Sources of information taken into account in the examination 1. USSR author's certificate N 286012, cl. H 01 B 3/00, 1968, 2. USSR author's certificate N, cl. H 01 L 21/32, 1970. 3. Authors certificate of the USSR f 509553, cl. C 04 B 35/00, 137.