RU2487849C2 - Method of producing powder of phases of layered titanates of s- and p-elements - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods of producing powder of phases of layered titanates of s- and p-elements, which are a base for piezoelectric materials that are widely used in modern aerospace industry. The disclosed method of producing phases of layered titanates of the type Bi₂A_n-1B_nO_3n+3 (A= Na, Ca, Cr, Bi) and (B=Ti) consists of three steps: a) synthesis, during acid hydrolysis of sodium titanates, of starting nano-clusters of polymer hydroxides of titanium (IV) at temperatures less than or equal to 370 K, peptisation of the hydrolysis product in a 60% nitric acid solution, and precipitating the nano-clusters from 0.1-0.3M (with respect to TiO₂) colloidal solutions at pH=8±0.5 using 5-10% ammonia solution at temperature below 280°K, b) reaction of the nano-clusters at temperature below 280°K with saturated Bi(NO₃)₃ solution while stirring, c) reaction of the primary intermediate product with a suspension of bismuth (III) hydroxide at standard conditions and thermal decomposition of the intermediate phase at temperature of 600-700°K; isothermal processing time ranges from 20 to 30 minutes. In order to dope with Cr³⁺ ions, a calculated amount of chromium acetate is added to the colloidal solution of titanium (IV) hydroxides at step a); in order to dope bismuth titanate with Na¹⁺ Ca²⁺ ions, sodium and calcium hydroxides are added to the suspension of bismuth nitrate.

EFFECT: low synthesis temperature of titanate phases and improved piezoelectric parameters of materials based thereon.

7 ex, 2 tbl

Description

The invention relates to a method for producing phase powders of layered titanates of the type Bi ₂ A _n-1 B _n O _{3n + 3} (A = Ca, Na, Cr, Bi) and (B = Ti), in which the perovskite-like sublattice B is a set of EO octahedra ₆ (E - cations of s-, p-, d- and f-elements with a charge from +1 to +7) connected by vertices, and type A cations fill the cuboctahedral voids of this sublattice. Layers with a perovskite-type structure are separated by (Bi ₂ O ₂ ) _z layers consisting of square BiO ₄ pyramids. The phase powders of layered titanates of a number of s- and p-elements (HSS) are the basis of piezomaterials widely used in modern aerospace industry. This is explained by the fact that they are characterized by record high stability of piezoelectric and dielectric parameters over a wide range of temperatures (70–900 K) and pressures (0.001 Pa – 300 mPa), due to the fact that the Curie point (Te) of layered titanates Bi ₂ A _{n– 1} B _n O _{3n + 3} (A = Ca, Na, Cr, Bi) and (B = Ti) lies above 900K, which significantly exceeds the values of Those, which are currently most widely used, of the phases of the lead titanate-zirconate system. The ferroelectric properties are possessed by the HSS phases with n = 2, 3, 4, 5.

Known methods for producing phase powders of layered titanates of a number of s- and p-elements can be divided into two types: high-temperature and low-temperature.

The first of them is carried out in the process of interaction between crystalline bismuth oxide or salts of its oxygen acids with titanium oxide (IV) at temperatures above 1000K for several hours to several days - the method of solid-phase reactions (hereinafter referred to as MTFR) [4, 5, 10 ]. As alloying additives, which are introduced into the initial mixture in the form of oxides or carbonates, compounds of sodium, chromium, niobium, calcium, boron and some others are used [1-3]. Functional materials made using layered piezophase powders synthesized in the framework of MTFR are characterized by a number of disadvantages, the main ones of which are: a) relatively low reproducibility of the electron phase transitions; b) a significant dependence of these parameters on temperature; c) change in parameter values over time (aging). The main reason for these shortcomings is the inability to accurately reproduce the macro- and microstructure of this type of ceramic, manufactured in the framework of traditional high-temperature technologies. In particular, the MTFR used in the synthesis of phases of layered titanates leads to a violation of the quantitative composition of the target reaction products due to evaporation of Bi ₂ O ₃ , sodium, potassium, and lead compounds from thermal preparations and sintering, as well as thermal decomposition of a number of alloying oxides of p- and d-elements. As a result of this, within the framework of this method, reaction products are formed that have high and uncontrolled nonequilibrium imperfection, both in the cationic and anionic sublattices. In turn, an increase in the concentration of nonequilibrium defects in powder particles promotes the production of ceramics and films with lower values of piezoelectric parameters and Curie points, as well as an increase in their electrical conductivity. The latter fact does not allow for an effective polarization of products, which leads to a further decrease in their electrophysical parameters (hereinafter referred to as the EFP). In addition, the technology of synthesis of piezophase powders based on MTFR does not provide their monodispersity. This stimulates an increase in the degree of uncontrolled secondary recrystallization of press preparations during sintering and, consequently, to obtain samples with a different combination of mechanical characteristics.

An attempt to eliminate certain disadvantages of MTFR is the use of active precursors, which can slightly reduce the activation energy of solid-phase reactions and, therefore, reduce the synthesis time of the target phase, and, sometimes, reduce the temperature of the process. The most promising achievements in this direction are: the method of thermal decomposition of salts [6] the cryochemical method [7, 8] and the method of co-precipitation [15, 17-19], which (with more or less success) are used for the synthesis of phases with a perovskite-type structure . However, attempts to use these technologies for the synthesis of phases of layered titanates have not yielded positive results. This is due to the fact that several phases with different numbers of perovskite-like layers, that is, with different numbers n, are simultaneously formed in the Bi ₂ O ₃ - TiO ₂ - A _x O _{y system} [20]. For example [21], in the Bi ₂ O ₃ - TiO ₂ - Fe ₂ O _{3 system} , phases of the composition Bi _{m + 1} Fe _m-3 Ti ₃ O _{3n + 3 are formed} (m can have both integer and fractional values in the range from 3 to 12). In this case, the temperature stability of phases rapidly decreases with increasing values of m. The decomposition of bismuth ferrotitanates is accompanied by the formation of iron oxides or system phases (TiO ₂ - Fe ₂ O ₃ ) along with Aurivillius phases with a smaller number m.

In addition, the disadvantages of these methods include significant energy costs, multi-stage, and in some cases environmental problems associated with the disposal of solvents or reaction by-products. In addition, the use of active precursors, solving some problems of MTFR (lowering the temperature and synthesis time), creates others associated with a high concentration of nonequilibrium defectiveness in the reaction products. The latter fact is related to the fact that the reaction product in this case is formed under conditions of a highly defective reaction zone, i.e. largely retains the type and high nonequilibrium concentration of the starting phases. Moreover, as was shown in a number of works [6, 7], the influence of the prehistory of the precursors on the nonequilibrium defectiveness of the reaction products can be manifested not only in the first, but also in the second “generation”.

At present, methods for the synthesis of layered titanates of the type Bi ₂ A _n-1 B _n O _{3n + 3} (A = Ca, Na, Cr, Bi) and (B = Ti,), alternative to MTFR, are not known.

One of the ways to solve these problems may be a technology based on the “chemical assembly” method, which involves reducing the activation energy of the synthesis process of piezophases of this type, as well as obtaining their powders with a given band and dispersion value. The method is based on the use of multinuclear polymer complexes of titanium (IV) as precursors having a similar structure with the sublattice (B) of the target product. In the synthesis process, these complexes play the role of matrices filled with cations forming the sublattice (A) of the layered phase. Both the synthesis of precursors and their filling, proceeding due to the processes of exchange or implementation, can be carried out under standard conditions (s.u.). This allows you to lower the temperature of the formation of the target reaction product by an average of 450-500 ° K and reduce the time of firing the mixture by 3-5 times. Reducing the activation energy of the process under discussion allows us to maintain the quantitative composition of the target products, which is almost impossible to do in the framework of traditional technologies based on the solid-phase reaction method. By changing the synthesis conditions of the initial matrices, the nature and concentration of the precursors interacting with them, as well as the heat treatment conditions of the primary intermediate phases, it is possible to purposefully change the average particle size of the synthesized powders from 15-30 nm to 1500 nm, and also, depending on the tasks, to vary the band their dispersion from 150 to 1200 nm. The manufacture of a mixture of a given particle size distribution allows you to control the processes of primary and secondary recrystallization, directly, in the process of sintering press preparations and, therefore, to form the optimal (for a certain combination of EPP) microstructure of the ceramic frame.

The closest in essence the totality of the features to the claimed invention is a method for producing barium titanate [23], which includes mixing titanium alkoxide and water (with the possible addition of other metals alkoxides to the system, for example bismuth), precipitation of titanium oxides from solutions at temperatures below 370K, their interaction with barium hydroxide, followed by thermal decomposition of the intermediate phase. As a result of these technological operations, the target phase powder with an average particle size of less than 0.45 microns is obtained. These powders have a narrow particle size distribution range and are sintered into dense ceramic.

The disadvantage of this method is the total time of the synthesis process, which is 1.5-3 hours, the process temperature is 60-80 ° C, which is 333-353K. As well as the use of a precursor (titanium alkoxide) that reduces the yield of Bi ₄ Ti ₃ O ₁₂ and Na _0,5 Bi _4,5 Ti ₄ O ₁₅ , which leads to the formation of impurity phases and a decrease in the value of piezoelectric parameters of materials created on the basis of this type of powder.

The inventive method allows to reduce the temperature of the synthesis of phases of this type by an average of 500K, to increase the piezoelectric parameters of materials based on them.

The technical result is achieved by the fact that the phase necessary in composition and structure is formed at a temperature below 280 K due to time-separated chemical processes, the first of which consists in the interaction of saturated solutions of nitrates of elements forming the sublattice A of the target phase with previously synthesized nanoclusters having similar structure and composition with a sublattice of the target phase. At the second stage, the obtained intermediate product, in the required quantitative ratio, is mixed with a saturated solution of bismuth (III) hydroxide with vigorous mechanical stirring of the mixture. Excellent signs are that, as precursors (nanoclusters) in this process, polymer forms of titanium hydroxides are used, formed by chains of a given number of titanium-oxygen octahedra, which can be obtained by hydrolysis of sodium titanates of different compositions at T≤370K, the degree of which increase due to the introduction of a 5 M solution of nitric acid into the system. Peptization of hydrolysis products is carried out using a 60% aqueous solution of HNO ₃ . To obtain polymeric forms of titanium hydroxides of the optimal structure, their deposition is carried out from 0.1-0.3 M (in TiO ₂ ) colloidal solution at a temperature of 270-280K with a 5-10% ammonia solution to a pH of 8 ± 0.5, and, for doping with Cr ³⁺ ions at the first stage, the calculated amount of chromium acetate is introduced into the colloidal solution of Ti (IV) hydroxides. At the second stage, the obtained nanoclusters are introduced into interaction with saturated solutions of nitrates of various elements of the composition MeNO ₃ , Me (NO ₃ ) ₂ and Me (NO ₃ ) ₃ at temperatures below 280K. At the end of the process, a saturated bismuth (III) hydroxide solution is introduced into the obtained intermediate product at a temperature of 280-298 K and atmospheric pressure, while stirring, where, for doping of bismuth titanate with Na ⁺ and Ca ^{2+ ions} , a bismuth nitrate suspension is added to the second stage of the process, sodium and calcium hydroxides are introduced. The amorphous phase formed in the system at a temperature of 600-700K, the isothermal treatment time of 20-30 minutes, decomposes with the formation of the target reaction product.

In example 7, it will be shown that the use of the precursor proposed in the prototype reduces the yield of Bi ₄ Ti ₃ O ₁₂ and Na _0,5 Bi _4,5 Ti ₄ O ₁₅ , leads to the formation of impurity phases and reduces the values of the piezoelectric parameters of materials based on powders of this type.

The invention is illustrated by examples 1-7 and table 1 - Parameters of the synthesis process of the phase Bi ₄ Ti ₃ O ₁₂ , as well as table 2 - EFP piezoceramics made from a mixture synthesized using various precursors.

Example 1. At the first stage, the powder of Na ₂ Ti ₃ O ₇ obtained by fusion of crystalline Na ₂ CO ₃ and TiO ₂ , without removing from the crucible, is treated with a 5M solution of nitric acid for 2-3 hours at T≤370K. The resulting suspension is separated by filtration and washed with distilled water until a negative reaction to sodium ions (flame photometry method). An excess of 60% HNO _{3 is} added to the resulting precipitate, which causes its peptization. In the obtained colloidal solution, the concentration of titanium compounds (in terms of TiO ₂ ) was determined by the gravimetric method. 100 ml of 0.3 M (TiO ₂ ) of this solution was neutralized at a temperature of 270-280K with 5% ammonia solution to pH 8. The resulting Ti (IV) hydroxide was separated from the mother liquor by centrifugation and transferred to a reactor cooled to 270K.

In a second step, a saturated solution containing 7.9 g of Bi (NO ₃ ) ₃ in 10 ml of a 3% HNO ₃ solution is added to the Ti (IV) hydroxide. The resulting mixture was stirred for 30 minutes using a high speed paddle mixer.

At the third stage of the process, a suspension containing 0.02 moles of bismuth (III) hydroxide is introduced into the system, the pH of the system is adjusted to a value of about 8 and the mixing process is repeated.

After delamination of the system, the primary reaction product of composition Bi ₄ Ti ₃ O _{12 is} separated from the liquid phase by centrifugation followed by decantation. The primary product is dried at a temperature of ≈ 330K for 30 minutes and then, to activate the primary recrystallization process, it is calcined at 600-700K (isothermal treatment time 20-30 minutes). The yield of crystalline Bi ₄ Ti ₃ O _{12 is} 11.54 g (more than 98% of theoretically possible). The synthesis time, taking into account the drying and stages of separation of precipitation from the liquid phase, is 3.5-4.5 hours.

Example 2. At the first stage, the powder Na ₁₀ Ti ₁₈ O ₄₁ (Na _2,2 Ti ₄ O ₉ ) obtained by fusion of crystalline Na ₂ CO ₃ and TiO ₂ , without removing from the crucible, is treated with a 5 M solution of nitric acid for 2 -3 hours at T≤370K. The resulting suspension is separated by filtration and washed with distilled water until a negative reaction to sodium ions (flame photometry method). An excess of 60% HMO _{3 is} added to the resulting precipitate, which causes its peptization. In the obtained colloidal solution, the concentration of titanium compounds (in terms of TiO ₂ ) was determined by the gravimetric method. 134 ml of a 0.3 M (TiO ₂ ) colloidal solution was neutralized at a temperature of 270-280K with a 10% ammonia solution to pH 8. The resulting Ti (IV) hydroxide was separated from the mother liquor by centrifugation and transferred to a reactor cooled to 270K.

In a second step, a saturated solution prepared by mixing 9.875 g of Bi (NO ₃ ) ₃ and 10 ml of a 0.5 M NaOH solution is added to Ti (IV) hydroxide. The resulting mixture was altered for 30 minutes using a high speed paddle mixer.

At the third stage of the process, a suspension containing 0.02 moles of bismuth (III) hydroxide is introduced into the system, the pH of the system is adjusted to a value of about 8 and the mixing process is repeated.

After delamination of the system, the primary reaction product of the composition Na _0.5 Bi _4,5 Ti ₄ O _{15 is} separated from the liquid phase by centrifugation, followed by decantation. The primary product is dried at a temperature of ≈330K for 30 minutes and then, to activate the primary recrystallization process, it is calcined at 600-700K (isothermal treatment time 20-30 minutes). The yield of crystalline Na _0.5 Bi _4.5 Ti ₄ O ₁₅ 13.66 g (more than 98% of theoretically possible). The synthesis time, taking into account the drying and stages of separation of precipitation from the liquid phase, is 3.5-4.5 hours.

Example 3. At the first stage, the powder of Na ₁₀ Ti ₁₈ O ₄₁ (Na _2,2 Ti ₄ O ₉ ) obtained by fusion of crystalline Na ₂ CO ₃ and TiO ₂ , without removing from the crucible, is treated with a 5M solution of nitric acid for 2- 3 hours at T≤370K. The resulting suspension is separated by filtration and washed with distilled water until a negative reaction to sodium ions (flame photometry method). An excess of 60% HNO _{3 is} added to the resulting precipitate, which causes its peptization. In the obtained colloidal solution, the concentration of titanium compounds (in terms of TiO ₂ ) was determined by the gravimetric method. To 134 ml of 0.3 M (TiO ₂ ) of this solution was added 5 ml of a 0.2 M solution of chromium (III) acetate and the system was neutralized at a temperature of 270-280K with 8% ammonia solution to pH 8. The resulting form of mixed Ti hydroxides (IV) and Cr (III) were separated from the mother liquor by centrifugation and transferred to a reactor cooled to 270K.

In a second step, a saturated solution prepared by mixing 9.48 g of Bi (NO ₃ ) ₃ and 10 ml of solution: 0.4 M in NaOH and 0.05 M in Ca (OH) _{2 is} added to Ti (IV) hydroxide. The resulting mixture was altered for 30 minutes using a high speed paddle mixer.

At the third stage of the process, a suspension containing 0.02 moles of bismuth (III) hydroxide is introduced into the system, the pH of the system is adjusted to a value of about 8 and the mixing process is repeated.

After delamination of the system, the primary reaction product of the composition Na _0.4 Ca _0.05 Bi _4.4 Cr _0.1 Ti ₄ O _{15 is} separated from the liquid phase by centrifugation followed by decantation. The primary product is dried at a temperature of ≈330K for 30 minutes and then, to activate the primary recrystallization process, it is calcined at 600-700K (isothermal treatment time 20-30 minutes). The yield of crystalline Na _0.4 Ca _0.05 B _4.4 Cr _0.1 Ti ₄ O ₁₅ 13.54 g (more than 97% of theoretically possible). The synthesis time, taking into account the drying and stages of separation of precipitation from the liquid phase, is 3.5-4.5 hours.

In examples 4 and 5, the synthesis of the Bi ₄ Ti ₃ O ₁₂ phase was carried out in a manner analogous to example 1, but with modified concentrations of the initial colloidal solution.

In examples 6 and 7, compared with example 1, the forms of titanium hydroxide precipitated from 0.3 M solutions of H ₂ [Ti (NO ₃ ) ₆ ] at 280K and formed during the hydrolysis of tetrabutylate Ti (VI), respectively, were used.

The use of the precursor proposed in the prototype reduces the yield of Bi ₄ Ti ₃ O ₁₂ and Na _0,5 Bi _4,5 Ti ₄ O ₁₅ , leads to the formation of impurity phases and reduces the values of the piezoelectric parameters of materials based on powders of this type.

Piezophase powders synthesized by the proposed method were used for the manufacture of piezoceramics using traditional ceramic technology (sintering of press preparations at standard pressure, temperatures of 1100-1050 ° for 2 hours). The sintering conditions of press preparations based on the phase of a fixed qualitative and quantitative composition were determined experimentally by constructing density curves - sintering modes. The density of the studied samples, having the form of disks with a diameter of 10 mm and a height of 1 mm, was not less than 92% of theoretically possible. Silver electrodes were applied to the parallel surfaces of the samples by incineration, the piezoelectric transducers were polarized in silicone oil at 430-450 K (polarizing field strength up to 6 kV / mm). The polarization conditions of the samples depended on their composition, and their optimal values were determined by analyzing standard curves: polarization parameters — properties. The piezoelectric and dielectric parameters of piezoceramics, as well as its Curie point, were determined according to GOST 12379-80.

The conditions for the process of synthesis of the piezophase, the composition of the impurity phases and the yield of the reaction product are shown in table 1.

Table 1 The parameters of the process of synthesis of the phase Bi ₄ Ti ₃ O ₁₂ Example Precursor shape S _m (according to TiO ₂ ) T ¹ process, K Ti hydroxide _{precipitation} pH % yield of the target phase Impurity phases one Na ₂ Ti ₃ O ₇ 0.3 270 8 99.6 - four Na ₂ Ti ₃ O ₇ 0.5 270 8 90.1 NaBiTi ₂ O ₆ 5 Na ₂ Ti ₃ O ₇ 0.1 270 8 94.8 Bi ₂ Ti ₂ O ₇ 6 H ₂ [Ti (NO ₃ ) ₆ ] 0.3 270 8 79.7 Bi ₂ Ti ₂ O ₇ 7 Ti (C ₄ H ₉ O) ₄ 0.3 270 8 88.1 Bi ₂ Ti ₂ O ₇

The electrophysical properties of piezoelectric ceramics made from a mixture obtained with the same system parameters using various precursors are presented in table 2.

table 2 EFP of piezoceramics made from a mixture synthesized using various precursors Way Phase composition E cf. charge particles (nm) D cf. grains of ceramic (nm) d ₃₃ · 10 ¹² (C / N) ε ^T ₃₃ / ε ₀ one Bi ₄ Ti ₃ O ₁₂ 28 820 10-12 85-90 2 Bi ₄ Ti ₃ O ₁₂ 46 630 14-16 120-140 3 Bi ₄ Ti ₃ O ₁₂ 87 490 17-19 150-160 one Na _0.5 Bi _4.5 Ti ₄ O ₁₅ 22 980 22-24 110-130 2 Na _0.5 Bi _4.5 Ti ₄ O ₁₅ 35 690 24-27 120-140 3 Na _0.5 Bi _4.5 Ti ₄ O ₁₅ 79 510 33-38 160-190 MTFR [3, 22] Na _0.5 Bi _4.5 Ti ₄ O ₁₅ + Cr ₂ O ₃ - - 28-29 106-110

(1) - precipitated from a 0.3 M solution of H ₂ [TiCl ₆ ]; (2) - formed during the hydrolysis of tetrabutylate Ti (VI); (3) - precipitated from a colloidal solution formed during the acid hydrolysis of sodium titanates.

The method proposed as an invention allows to reduce the temperature of the synthesis of phases of the indicated type by an average of 500K and to increase the piezoelectric parameters of materials based on them

Information sources

1. SU No. 1390223 of 07/30/1986, Piezoelectric ceramic material. Shitsa D.A., Rivkin V.I., Borisova I.S., Freidenfeld E.Zh., Kochetigov V.V., Novikova Z.P.

2. RU No. 93030132 dated 06/10/92, “Piezoelectric Ceramic Material” / Panich A.E., Minchina M.G., Smotrikov V.G., Faynrider D.E., Polonskaya A.M.

3. RU No. 98102096/03 dated 01/26/1998. Piezoelectric ceramic material / Vusevker Yu.A., Feinrider D.E., Panich A.E., Gorish A.V., Zlotnikov V.A.

4. Tretyakov Yu.D. Solid phase reactions. - M.: “Chemistry”, 1978. 360 p.

5. Kingery U.D. Introduction to ceramics. - M.: Publishing House for Construction, 1967.500 p.

6. Limar T.O., Borsch A.N., Slatinskaya I.G., Mudrolyubova L.P., Nenasheva E.A. Chemical methods for producing modern ceramic capacitor materials. M .: NIITEKHIM. 1998.62 p.

7. Levin B.E., Tretyakov Yu.D., Letiuk L.M. Physico-chemical bases of production, properties and application of ferrites. - M.: Metallurgy, 1979. - 470 p.

8. Tretyakov Yu.D., Oleinikov NN, Mozhaev A.P. Fundamentals of cryochemical technology. M., "Higher School", 1987. 211 p.

9. Knotko A.V., Presnyakov I.A., Tretyakov Yu.D. Solid State Chemistry. M.: Academy, 2006 .-- 304 s

10. Okazaki K. Technology of ceramic dielectrics. / Per. with japan. M .: Energy. 1976. P.336.

11. Limar T.F., Drummer P.M., Savoskina A.I., Velichko Yu.N. Comparative evaluation of barium titanate obtained in different ways. // Electronic equipment. Ser. 8. "Radio components." 1971. Issue 2. (23). - S.33-41.

12. Bauer A., Buhling D., Gesemann H.-J., Heike G., Screckenbach W. Technologie und Anwendungen von Ferroelectrica. // Leipzig .: Academie Ferlagssgesellschaft Geest & Portig K.-G. 1976. S.548

13. Ovramenko N.A., Shvets L.I., Ovcharenko F.D., Kornilovich B.Yu. Kinetics of hydrothermal synthesis of barium metatitanate. / Izv. USSR Academy of Sciences. Inorg. Mater. 1979.V.15, No. 11. - S.1982-1985.

14. Venigalla S., Clancy D.J., Miller D.V., Kerchner J.A., Costantino S.A. Hydrothermal BaTiO3 - based aqueous slurries. // Amer. Cer. Soc. Bull. V.78, No. 10. 1999. R. 51-54.

15. Belyaev I.N., Artamonova S.M. Study of titanium and zirconium hydroxides and co-precipitated titanium and lead, zirconium and lead hydroxides // Zh. nonorgan, chemistry. 1966. 11. No. 3. - S. 464-467.

16. Nesterov A.A., Lupeyko T.G., Nesterov A.A. / Proceedings of the international scientific-practical conference "Fundamental problems of piezoelectric instrumentation." 1999. - S.254-261

17. Nesterov A.A., Lupeyko T.G., Nesterov A.A., Pustoval L.E. The influence of the synthesis method on the electrophysical properties of ceramics of the composition Pb _0.76 Ca _0.24 Ti _0.94 (Cd _0.5 W _0.5 ) _0.06 O ₃ Inorganic materials. - 2004. - T. 40., No. 12. S.1530-1534

18. Zabelina A.E., Prilipko Yu.S. Features of the synthesis of manganite lanthanum perovskites. // Collection of scientific papers "Bulletin of the Donbass National Academy of Construction and Architecture". Donbas. 2007.16 s.

19. Rodionova Yu.M., Slyusarenko E.M., Lunin V.V. Prospects for the use of alkoxotechnology in heterogeneous catalysis // Advances in Chemistry. 1996. 65. No. 9. - S.865-879.

20. Phanichphant S., Heimann R.B. Hydrothermal Synthesis of Submicron- to Nano-Sized Ferroelectric Powders: Properties and Characterization. CMU Journal 2004). V.3 (2). p.113 132

21. Lomanova N.A., Ugolkov V.L., Gusarov V.V. Thermal properties of Aurivillius phases in the Bi ₄ Ti ₃ O ₁₂ - BiFeO _{3 system} . Phase transitions, ordered states, and new materials. 2006.05.09. c.1-4

22. Eknadiosyants E.I., Proskuryakov L.M. Domain structure, microstructure, electrophysical properties of ferroceramics based on Bi ₄ Ti ₃ O ₁₂ . Piezoelectric materials and piezoelectric transducers. Rostov-on-Don. 1989. Iss. 8. S.19-26.

23. RU 2039024, from 01.26.1994 A method for producing barium titanate, LLC Soliton. Authors: Golubko L.A., Ivanova N.V., Vakhlyueva V.B., Glushkova A.A., Rumyantseva L.M., Yanovskaya M.I., Kovsman E.P.

Claims (1)

A method for producing phase powders of layered titanates of the type Bi ₂ A _n-1 B _n C _{3n + 3} (A = Na, Ca, Cr, Bi) and (B = Ti), including a) synthesis of polymer starting nanoclusters during the acid hydrolysis of sodium titanates titanium (IV) hydroxides at temperatures <370 K, peptization of the hydrolysis product in a 60% solution of nitric acid, and also the deposition of nanoclusters from 0.1-0.3 M (according to TiO ₂ ) colloidal solutions at pH 8 ± 0.5 using 5-10% solution of ammonia at a temperature below 280 K, and for the doping of Cr ³⁺ ions in the colloidal solution of hydroxides of Ti (IV) is introduced calculated amount aij chromium acetate; b) the interaction of nanoclusters at temperatures below 280 K with a saturated solution of Bi (NO ₃ ) ₃ with stirring; for doping of bismuth titanate with Na ¹⁺ Ca ^{2+ ions} , sodium and calcium hydroxides are introduced into the bismuth nitrate suspension; c) the interaction of the primary intermediate product with a suspension of bismuth (III) hydroxide under standard conditions and the thermal decomposition of the intermediate phase at a temperature of 600-700 K, the isothermal treatment time is from 20 to 30 minutes, where titanium hydroxides formed during the acid process are used as initial components hydrolysis of sodium titanates, as well as a suspension of bismuth nitrate and hydroxide, which sequentially (in two stages) interact with titanium hydroxide nanoclusters with stirring of the system in st under standard conditions, which ensures the production of bismuth titanates of a given composition and structure.