MODIFYING AGENT AND METHOD OF ALTERING THE ELECTROPHYSICAL AND MAGNETIC PROPERTIES OF A CERAMIC

Abstract

The invention lies within the field of ceramic technology, in particular ceramic production technology. Namely, it refers to modifier that alters the electrophysical and magnetic properties of ceramics, which is a product of technological processing of one or more batch mix components of the specified ceramic sample, the relevant ceramic sample, an intermediate product obtained after baking of the relevant ceramic sample, a known alloying agent, or a combination thereof. It also refers to the method for altering the electrical and magnetic properties of ceramics, according to which the dry batch mix is saturated with the claimed modifier, followed by baking and sintering according to the relevant ceramic sample production technology. The invention provides for the production of modified ceramics with improved electrical and magnetic properties, without the formation of impurity defects in the crystalline structure of the resulting ceramics.

Claims

1. A modifier that alters electrical and magnetic properties of ceramics, which presents a technology-processed product of one or several components of the batch mix of a ceramic sample, the modifier comprising: the ceramic sample, an intermediate product obtained after baking of the ceramic sample, an alloying agent, or a combination thereof.

2. The modifier according to claim 1, wherein the technology-processed product is an aqueous or aqueous-alcoholic solution obtained by resulting from multiple serial dilutions of a stock substance of a parent substance in combination with external mechanical actionrepeated shaking of each dilution, where the parent substance is selected from one or several components of the batch mix used to make ceramics, the relevant ceramic sample, the intermediate product obtained after the baking during the production of the ceramic sample, or the alloying agent.

3. The modifier according to claim 1, wherein the batch mix components are the components used for the making of the ceramic sample, including the alloying agents.

4. The modifier according to claim 1, wherein the ceramic sample is a high-temperature superconductor (HTSC), or a piezoelectric material.

5. The modifier according to claim 4, wherein the batch mix components used to obtain superconducting ceramics (HTSC) are chosen from powdered oxides, carbonates, peroxides, hydroxides, or salts of the components used to produce ceramics under conventional technology.

6. The modifier according to claim 5, wherein the superconducting ceramics is YBa.sub.2Cu.sub.3O.sub.7.

7. The modifier according to claim 4, wherein the batch mix components used to obtain piezoelectric ceramics is chosen from oxides of titanium, zirconium and lead, bismuth titanate, or barium titanate.

8. The modifier according to claim 7, wherein the piezoelectric matter is Bi.sub.3TiNbO.sub.9.

9. The modifier according to claim 3, wherein the alloying agents used for the production of superconducting ceramics are Ag and AgNO.sub.3.

10. The modifier according to claim 3, wherein the alloying agents used for the production of piezoelectric ceramics are Fe.sub.2O.sub.3 and Cr.sub.2O.sub.3.

11. A method of alteration of the electric and magnetic properties of ceramics, the method comprising the steps of: a) a dry mixture of the parent components of the batch mix of the relevant ceramics is homogenized; b) the dry mixture is saturated with modifier of claim 1; c) the modifier saturated mixture is baked; d) plasticizer is added, and the final modified ceramic sample is molded; e) the modifier saturated mixture is sintered according to the relevant ceramic sample production technology.

12. The modifier according to claim 11, further including a modifier admixture stage of claim 1 after baking but before sintering.

13. The modifier according to claim 11, wherein the plasticizer is an organic polymer, chosen from polyvinyl alcohol, castor oil, wood resin, paraffin, wax, or sulfite alcohol stillage.

14. A method of alteration of the electric and magnetic properties of ceramics, the method comprising the steps of: a) a dry mixture of the parent components of the batch mix of the relevant ceramics is homogenized; b) the dry mixture is baked; c) the dry mixture is saturated with modifier of claim 1; d) plasticizer is added and the resulting modified ceramic sample is molded; e) the modifier saturated mix is sintered according to the relevant ceramic sample production technology.

15. The modifier according to claim 14, wherein the plasticizer is organic polymer, chosen from polyvinyl alcohol, castor oil, wood resin, paraffin, wax, or sulfite alcohol stillage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The present invention is illustrated by the following examples, together with the accompanying drawings:

[0075] FIG. 1a: Diffraction patterns of the synthesized samples Nos. 1-6 with the admixture of Ge crystal powder as an internal standard (on the right side of the diffraction patterns, the batch numbers of the samples and the baking temperature T.sub.s are given; above the reflections, the Miller indices of the corresponding crystallographic planes are given).

[0076] FIG. 1b. Diffraction patterns of the synthesized samples Nos. 7-13 with the admixture of Ge crystal powder as an internal standard (the numbers on the right side of the diffraction patterns indicate the batch number of the samples; the baking temperature T.sub.s=960? C.).

[0077] FIG. 2. Rhombic cell a, b, c of YBa.sub.2Cu.sub.3O.sub.7 phase with Y, Ba, Cu, and O atoms.

[0078] FIG. 3. Dimensions of the rhombic cell of the HTSC phase YBa.sub.2Cu.sub.3O.sub.y in samples of batches Nos. 1-13: black dots denoting the samples after baking and prior to pressing into tablets and sintering; red dots denoting the samples pressed into tablets and sintered; empty dots denoting the samples obtained at an intermediate stage of their synthesis at a temperature lower than the final synthesis temperature.

[0079] FIG. 4. Diffraction patterns taken in ?-2? geometry from the powder obtained by grinding hot-pressed Bi.sub.3TiNbO.sub.9 samples and from the sections perpendicular (cut 2) and parallel (cuts 1 and 3) to the ceramic pressing axis (with the admixture of Ge crystal powder as an internal standard) and the results of their indexing. The Miller indices of the appropriate crystallographic planes are indicated above the reflections.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Modifier Preparation

[0080] Below is an example of obtaining a modifier by trituration with subsequent dilution of the resulting trituration in aqueous or aqueous-alcoholic solution to obtain a release-active form of silver nitrate (RA AgNO.sub.3) in the form of a mixture of centesimal dilutions C12C30C50. For parent substance, dry silver nitrate powder (AgNO.sub.3) is used. Lactose monohydrate is used as a neutral carrier in trituration.

[0081] To obtain successive triturations C1-C3 (centesimal scale, 1 unit of the parent substance or the previous trituration (C1 or C2) and 99 units of lactose monohydrate is taken), the following procedure is observed. The required amount of lactose monohydrate is divided into 3 equal portions. The first portion of lactose monohydrate is placed in a porcelain mortar and ground to close the pores of the mortar. Then the entire amount of the dry powdered silver nitrate is added, and the resulting mixture is ground with effort, after which the powder is raked with a spatula and scraped off the walls of the mortar; this operation is repeated once more. Then the second and the third portions of the neutral carrier are added sequentially. Thus, trituration C1 is obtained. Then, similar to the above process, C2 trituration is obtained (adding 1 unit of C1 trituration to 99 units of lactose) and C3 trituration (adding 1 unit of C2 trituration to 99 units of lactose).

[0082] The subsequent dilution C4 is obtained from 1 unit of the trituration of C3 and 99 units (centesimal scale) of 25% aqueous solution of ethyl alcohol. These components are thoroughly mixed until smooth, shaking the closed bottle vertically. C5 dilution is obtained from 1 unit of C4 dilution and 99 parts of 25% aqueous solution of ethyl alcohol, thoroughly mixing the indicated components until smooth, shaking vertically. The required degree of dilution is obtained by repeating the previous steps as appropriate.

[0083] Further, to obtain release-active silver nitrate in the form of a mixture of dilutions, according to this example, C12C30C50, centesimal dilutions are prepared according to the above-described technology until dilution which is 3 steps of centesimal dilutions less than the final solution of C12C30C50. For this dilution, C9, C27 and C47, one unit of each dilution (in this example, the volume ratio is 1:1:1) are put into one container containing 97 units of a 70% aqueous solution of ethyl alcohol (for centesimal dilution). The resulting mixture is then sequentially diluted twice in a ratio of 1 to 100, using 70% aqueous solution of ethyl alcohol at the penultimate stage, and 36% aqueous solution of ethyl alcohol at the last stage, thoroughly mixing these components until smooth, shaking the closed bottle with the resulting solution vertically after each dilution. At the last stage, modifier is obtained, a release-active form of silver nitrate (RA AgNO.sub.3), by diluting silver nitrate by 100.sup.12, 100.sup.30, 100.sup.50 times, which in terms of homeopathic technology corresponds to a mixture of centesimal dilutions C12, C30 and C50.

[0084] The above-described method of obtaining modifier in the form of release-active dilutions of silver nitrate is one of the embodiments of this invention. To obtain a modifier according to the present invention, decimal, hundredth, thousandth aqueous or aqueous-alcoholic dilutions of the starting substance can be used, starting with C2 (i.e., with a dilution of the starting substance by 100.sup.2 times), as well as any combinations thereof (e.g. C2+D34+M45, D20+C4, etc.) and their ratio in the mixture (for example, 1:1:2, 2:3, etc.).

Example 2

Obtaining a Modified HTSC Using the RA AgNO.SUB.3 .Modifier

[0085] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 400-800? C. before weighing.

[0086] For further synthesis of pure HTSC phase Y-123, mixtures of composition Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill. As a result, the size of the component particles decreased to a few micrometers.

[0087] The homogenized batch mixture was further saturated with a modifier, release-active silver nitrate (RA AgNO.sub.3) in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to Example 1. For this, 30 ml of RA AgNO.sub.3 solution was added to 80 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0088] The samples treated with the modifier based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, seven incinerations were carried out.

[0089] Taking into account the data on low melting temperatures (T.sub.m) of AgNO.sub.3 (T.sub.m=210? C.) and decomposition temperatures (T.sub.dec) of BaO.sub.2 (T.sub.dec?500? C.), the first baking was carried out with an intermediate exposure at 240? C. for five hours, and with slow heating to the maximum baking temperature. The latter was relatively low (870? C.). Such first baking scheme is due to the need to ensure smooth entry of Ag and Ba atoms into the Y-123 crystal lattice formed during the baking, in order to obtain samples with a uniform distribution of chemical components over the volume.

[0090] The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders.

[0091] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0092] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA from the samples). Then the samples underwent a 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and the long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y?6.8-7.0).

[0093] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 3

[0094] Obtaining a Modified HTSC Containing Alloying Agent AgNO.sub.3 Using the RA AgNO.sub.3 Modifier.

[0095] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) and silver nitrate AgNO.sub.3 (chemically pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 400-800? C. before weighing.

[0096] For further synthesis of HTSC phase Y-123 with admixtures of silver atoms, 200 g of mixture of Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO+5 wt % of AgNO.sub.3 were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill.

[0097] The homogenized batch mixture was further saturated with a modifier, release-active silver nitrate (RA AgNO.sub.3) in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to Example 1. For this, 30 ml of RA AgNO.sub.3 solution was added to 80 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0098] The samples treated with the modifier based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, seven incinerations were carried out. The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders.

[0099] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0100] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA and its decomposition products from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y 6.8-7.0).

[0101] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 4

Obtaining a Modified HTSC Using the RA CuO Modifier (Double Modifier Treatment)

[0102] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 400-800? C. before weighing.

[0103] For further synthesis of pure HTSC phase Y-123, mixtures with composition Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill.

[0104] The homogenized batch mixture was further saturated with a modifier, release-active copper oxide (RA CuO) in the form of a mixture of dilutions of D50D20, obtained according to Example 1. For this, 22.5 ml of RA CuO solution was added to 60 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0105] The samples treated with release-active copper oxide dilutions based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, three incinerations were carried out. The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders.

[0106] After the baking, the resulting powder was re-saturated with modifier, i.e. release-active form of copper oxide (RA CuO) in the form of a mixture of dilutions D50D200 in a ratio of 1:2, according to the method disclosed in Example 1. For this, 30 ml of RA solution was added to 80 g of the CuO powder, and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0107] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0108] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA and its decomposition products from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2CusO.sub.y, y?6.8-7.0), optimal from the point of view of superconducting properties.

[0109] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 5

[0110] Obtaining a Modified HTSC Using the RA HTSC Modifier of the YBa.sub.2Cu.sub.3O.sub.7-y Phase Obtained after the Sintering Stage

[0111] To obtain the modified HTSC of YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), previously obtained HTSC of Y-123 phase was used for initial component. The resulting powder was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill.

[0112] The homogenized powder was further saturated with modifier, release-active HTSC of YBa.sub.2Cu.sub.3O.sub.7-y phase obtained after the sintering stage (PA YBa.sub.2Cu.sub.3O.sub.7-y) in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to the procedure described in Example 1. For this, 22.5 ml of RA YBa.sub.2Cu.sub.3O.sub.7-y solution was added to 60 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0113] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0114] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA and its decomposition products from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y?6.8-7.0), optimal from the point of view of superconducting properties.

[0115] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 6

[0116] Obtaining a Modified HTSC Using the Batch Mix of RA HTSC Modifier of the YBa.sub.2Cu.sub.3O.sub.7-y Phase

[0117] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 800? C. before weighing.

[0118] For further synthesis of pure HTSC phase Y-123, batch mixtures with composition Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill. As a result, the size of the component particles decreased to a few micrometers.

[0119] The homogenized batch mixture was further saturated with a modifier, release-active form of Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO batch mix in the form of a mixture of dilutions of C12C30C50, obtained according to Example 1. For this, 30 ml of Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO release-active batch mix solution was added to 80 g of the homogenized batch mix and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0120] The samples treated with release-active form of Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO batch mix based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, seven incinerations were carried out. The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders.

[0121] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0122] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y?6.8-7.0), optimal from the point of view of superconducting properties.

[0123] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 7

[0124] Obtaining a Modified HTSC Using the RA Powder Modifier of the YBa.sub.2Cu.sub.3O.sub.7-y Phase Obtained after the First Baking

[0125] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 800? C. before weighing.

[0126] For further synthesis of pure HTSC phase Y-123, batch mixtures with composition Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill. As a result, the size of the component particles decreased to a few micrometers.

[0127] The samples based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, seven incinerations were carried out. The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders with already formed HTSC structure.

[0128] The powder samples (after baking) were further saturated with a modifier, release-active YBa.sub.2Cu.sub.3O.sub.7-y, obtained after the baking, in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to Example 1. For this, 22.5 ml of RA YBa.sub.2Cu.sub.3O.sub.7-y solution was added to 60 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0129] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0130] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y?6.8-7.0), optimal from the point of view of superconducting properties.

[0131] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 8

[0132] Obtaining a Modified HTSC Using the Modifier of the RA Batch Mix of Y.sub.2O.sub.3, BaO.sub.2, CuO Before the Primary Baking and the RA Phase of YBa.sub.2Cu.sub.3O.sub.7-y (after Baking) Before Sintering

[0133] To obtain the modified HTSC of the YBa.sub.2Cu.sub.3O.sub.7-y phase (Y-123), oxides Y.sub.2O.sub.3 (grade ITO-2), CuO (extra pure grade 9-2), BaO.sub.2 (pure grade) were used for initial components. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 800? C. before weighing.

[0134] For further synthesis of pure HTSC phase Y-123, batch mixtures with composition Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO were prepared. The mix of components was then homogenized by stirring for an hour in ethanol in a Pulverisette-6 centrifugal ball mill. As a result, the size of the component particles decreased to a few micrometers.

[0135] The homogenized batch mixture was further saturated with a modifier, release-active form of Y.sub.2O.sub.3.Math.4BaO.sub.2.Math.6CuO batch mix in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to Example 1. For this, 30 ml of release-active solution of the same batch mix was added to 80 g of the homogenized batch mix and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0136] The modifier-treated samples based on the Y-123 HTSC phase were synthesized via solid-phase reactions in an SNOL 12/16 furnace, in air. The batch mixes were repeatedly baked, sequentially increasing the maximum temperature from 870? C. to 960? C. The resulting products were subject to intermediate grinding, and their phase composition was controlled by X-ray phase analysis method. In total, seven incinerations were carried out. The synthesis yielded polycrystalline samples in the form of black homogeneous-looking powders.

[0137] The powder samples (after baking) were once more saturated with another modifier, release-active HTSC form of YBa.sub.2Cu.sub.3O.sub.7-y, obtained after the baking, in the form of a mixture of centesimal dilutions of C12C30C50, obtained according to Example 1. For this, 22.5 ml of the same batch mix solution was added to 60 g of the homogenized mixture and stirred with a spatula to obtain a homogeneous moist mixture. Then the resulting moist powder was dried at +35? C. for 6 hours until the liquid evaporated.

[0138] Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed using a Shimadzu hydraulic press and a set of appropriate molds.

[0139] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 960? C. First, the samples underwent a 5-hour heating to 150? C., and then were kept at this temperature for an hour (in order to achieve smooth removal of PVA from the samples). Then the samples underwent a linear 5-hour temperature increase from 150? C. to 960? C. and were kept at 960? C. for 3 hours (ceramic sintering). Then the furnace temperature was slowly lowered to 300? C. (over 40 hours) and the samples were kept at 300? C. for 30 hours, after which the samples were removed from the furnace. The slow cooling from 960? C. to 300? C. and long exposure at 300? C. was employed to ensure the entry of oxygen from the surrounding atmosphere into the Y-123 HTSC phase and to achieve the y oxygen index of the Y-123 phase (YBa.sub.2Cu.sub.3O.sub.y, y?6.8-7.0), optimal from the point of view of superconducting properties.

[0140] After the final sintering, the structure of the samples was analyzed on an X-ray diffraction meter. The diffraction patterns of the samples correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase in terms of the position and reflections intensities [see Example 9].

Example 9

Results of X-Ray Phase Analysis of all Obtained Samples

[0141] The following samples of superconducting ceramics were analyzed: [0142] Sample 1: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking, and a mixture of powders after the first baking, treated with RA YBa.sub.2Cu.sub.3O.sub.7-y (C12C30C50) before sintering; [0143] Sample 2: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking, and a mixture of powders after the first baking, treated with in-process monitoring before sintering, in-process monitoring; [0144] Sample 3: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking, and a mixture of powders after the first baking, treated with 36.7% ethanol before sintering, monitoring (without SVR components); [0145] Sample 4: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking; [0146] Sample 5: A mixture of powders (batch mix) treated with in-process monitoring, release-active lactose; [0147] Sample 6: A mixture of powders (batch mix) treated with 36.7% ethanol, monitoring (without RA components); [0148] Sample 7: Powder with already formed HTSC structure YBa.sub.2Cu.sub.3O.sub.7-y before its sintering into ceramics, treated with RA powder of YBa.sub.2Cu.sub.3O.sub.7-y phase (C12C30C50) obtained before the first sintering; [0149] Sample 8: Powder with already formed HTSC structure YBa.sub.2Cu.sub.3O.sub.7-y before its sintering into ceramics, treated with in-process monitoring; [0150] Sample 9: Powder with already formed HTSC structure YBa.sub.2Cu.sub.3O.sub.7-y before its sintering into ceramics, treated with 36.7% ethanol, monitoring (without RA components); [0151] Sample 10: A mixture of powders (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0152] Sample 11: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0153] Sample 12: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with in-process monitoring; [0154] Sample 13: Intact mixture of Y.sub.2O.sub.3, BaO.sub.2, CuO powders (batch mix) without additives and treatments, prepared according to standard procedure (general control).

[0155] X-ray phase analysis (XPA) of all samples after their synthesis and after sintering was performed on an automated DRON-4 X-ray diffraction meter using filtered copper radiation and Ge crystal powder as an internal standard.

[0156] Diffraction patterns of the samples (FIGS. 1a and 1b), by their positions and reflection intensities correspond to the literature data on the YBa.sub.2Cu.sub.3O.sub.7-y phase [Powder Diffraction files of the International Center for Diffraction Data (ICDD). Accessed 7 Dec. 2020. https://www.icdd.com/pdfsearch/, Bush A. A. Synthesis of metal oxide superconductors. High-temperature superconductivity, intersectoral scientific and technical almanac. Moscow: VIMI, 1989, issue 1, pp. 57-67. Bush A. A. Technology of ceramic materials, peculiarities of obtaining ceramics of HTSC phase YBa.sub.2Cu.sub.3O.sub.7-y phase. Moscow: MIREA, 2000, p. 79]. All reflections of diffraction patterns of the samples baked at 960? C., as well as the sintered samples, refer to the Y-123 based phase, with no significant impurity reflections observed. In this regard, it can be concluded that the synthesized samples are practically single-phase, they consist of an HTSC phase based on Y-123.

[0157] The diffraction pattern of sample No. 1 (FIG. 1a) obtained after baking at 880? C. contains many reflections that are not indicated on the basis of the HTSC unit cell parameters of Y-123 phase, which indicates the multiphase nature of this sample and the insufficiency of baking temperature of 880? C. to obtain the Y-123 phase by the solid-phase reactions method.

[0158] Using the data of precision measurements of the Bragg angles of X-ray reflections 2? (the measurement error not exceeding 0.02?) and the special-purpose software CELREF for unit cell refinement [http://www.ccp14.ac.uk/tutorial/lmgp/celref.htm (CELREF for unit cell refinement)], all the diffraction patterns obtained from samples 1 to 13 (FIG. 1a,b) were indexed on the basis of a rhombic unit cell where a=3.82, b=3.88 and c=11.66 ? (FIG. 2). As a result of the indexing, data were obtained on the refined unit cell dimensions for the Y-123 high-temperature superconducting phase in all synthesized and sintered samples No. 1-13 (FIG. 3).

[0159] It can be noted that, in a first approximation, the unit cell dimensions of the Y-123 HTSC phase correspond to the known literature data on this phase. However, a precise comparison of the unit cell sizes shows a scatter of their Y-123 phase values in different batches of synthesized samples, and also in the samples obtained after their synthesis and after sintering, respectively (FIG. 3). This data variability is most likely caused by uncontrolled variations in the oxygen index y of the samples under consideration, caused by the effect of RA treatment.

Example 10

Assessment of the Temperature Dependence of Electrical Resistance

[0160] Electrical resistance R of the samples was measured using the four-probe method; the survey current in all cases was 50 mA. An RHTS-100 platinum thermometer (Honeywell, USA) was used for temperature sensor; its resistance was measured with a GOM 802 DC milliohm meter (GW-Instek, Taiwan), and the voltage across the potential contacts of the sample was measured with a V7-78/1 voltmeter (AKIP, Russia). The data yielded by these devices were fed into a computer and recorded into a file for further processing.

[0161] A sharp drop in resistance is observed on R(T) dependences upon transition to the SC state, while three characteristic sections can be distinguished on R(T) dependence: (a) an almost horizontal high-temperature section in the normal state of the sample; (b) a section with a sharp drop in resistance, with co-existent normal and LF phases caused by LF transition; (c) a low-temperature section with low resistance determined by the motion of LF vortices (flux flow region, FF). Five temperatures are usually distinguished as the temperatures characterizing the SP transition: the temperature of the beginning of the transition T1, at which the resistance decreases to 0.9 R.sub.n (R.sub.n being the resistance in the normal state near T.sub.c); the temperature of the end of the transition T3, at which the resistance decreases to 0.1 R.sub.n; the temperature of the beginning of the SC fluctuations T2, determined by the onset of the deviation of the dependence R(T) from the linear law; the temperature of the middle of the transition T4, at which R=0.5R.sub.n; FF is the temperature of the end of the SP transition, below which the resistance is determined by the motion of the SP vortices.

[0162] The following samples were used for the analysis: [0163] Sample 1: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking; [0164] Sample 2: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0165] Sample 3: Intact mixture of powdered Y.sub.2O.sub.3, BaO.sub.2, CuO (batch mix) without admixtures, un-processed, prepared according to standard procedure (general supervision).

[0166] The results of the obtained measurements are presented in Table 1 (Typical temperatures of the SC transition determined according to R(T) dependences).

TABLE-US-00001 TABLE 1 Typical temperatures of the SC transition determined according to R(T) dependences # T1, K T3, K T.sub.FF, K 1 89.0 85.9 83.3 2 89.3 88.2 87.0 3 86.3 83.9 82.9

[0167] An increase in FF temperature was manifest upon addition of a ligand, together with a modifier in the form of the RA AgNO.sub.3.

Conclusion

[0168] Even a slight increase in the T.sub.FF temperature makes it possible to stabilize the magnetic state of the superconductor and to eliminate the danger of magnetic flux jumps at the temperature of liquid nitrogen, which simplifies the formation of magnetic systems using this material.

Example 11

Measurement of the Real Part of the Magnetic Susceptibility (Meissner Effect)

[0169] In a superconducting transition, the real part of the magnetic susceptibility ?(?) in an alternating magnetic field of small amplitude changes from 0 in the normal value to the minimum value ?.sub.min in the SC state. This is due to the expulsion of the magnetic field from the bulk of the sample during the SC transition. At low frequencies (<10 kHz) and for constant external magnetic field, this behavior is called Meissner effect.

[0170] For an ideal type I superconductor, the magnetic susceptibility takes on the value of ?1. In mixed state, the value ? can take values of the range [?1; 0], whi?h is determined by the fraction of the superconducting phase in the sample.

[0171] If an inductance coil (L.sub.0) is available where the sample under analysis is used as the core, then, in the course of SC transition, its inductance will decrease to L.sub.1, which is determined by the fraction of the SC phase volume in the core. Thus, ?L=L.sub.1?L.sub.0 turns out to be proportional to the real part of the magnetic susceptibility ?(?).

[0172] The temperature values typical for the SC transition can be obtained from the graphs of the temperature dependences of the real part of the magnetic susceptibility ? and its temperature derivative: [0173] temperature of the onset of the superconducting transition T.sub.max, at which a sufficient amount of the superconducting phase emerges, forming a closed loop with a ?urr?nt in th? s?mpl?; [0174] temperature of the end of the superconducting transition T.sub.min, at which almost the entire sample goes over into the SC state, and the field is pushed out of the bulk (Meissner ?ff?t); [0175] temperature T.sub.01, at which almost the entire sample remains in a mixed state, th?m?gn?ti?f?ld p?n?tr?ting ?th? ?ntir?v?lum?; [0176] temperature T.sub.m at which the maximum of the derivative d?(T)/dT is ?bs ?rv ?d; [0177] temperature T.sub.d ?t whi?h th? first S? flu?tu?ti?ns ?pp ??r in th? s?npl?; ?s ?rule, there is still no closed conducting loop.

[0178] Thus, from the ? (T) diagrams show the onset T.sub.max and the end T.sub.min temperatures of the transition to the SC state, and also the temperatures T.sub.01, T.sub.m and T.sub.d, the width of the SC transition (T.sub.max?T.sub.min), and the magnitude of the Meissner effect in percent with respect to the reference sample.

[0179] The following samples were used for the analysis: [0180] Sample 1: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking; [0181] Sample 2: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0182] Sample 3: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with in-process monitoring; [0183] Sample 4: Intact mixture of powdered Y.sub.2O.sub.3, BaO.sub.2, CuO (batch mix) without admixtures, un-processed, prepared according to standard procedure (general supervision).

[0184] The measurements were carried out on specimens in the shape of cylindrical disks 10 mm in diameter and 2 mm thick. The temperature was measured with an RHTS-100 platinum thermometer (Honeywell, USA). The inductance of the measuring coil was measured by an E7-20 LCR meter manufactured by MNIPI (Minsk, Belarus).

TABLE-US-00002 TABLE 2 Superconducting transition temperatures obtained from magnetic measurements # T.sub.min T.sub.max T.sub.01 ?? % T.sub.m T.sub.d Notes 1 84.3 90.5 88.5 92 87.5 91.0 2 82.3 89.6 88.4 96 87.7 91 2 SC transitions 3 82.5 90.2 89.5 88 87.9 90.9 2 SC transitions 4 86.0 91.2 89.8 85 89.2 92

[0185] Addition of a ligand led to an increase in the magnitude of the Meissner effect, while the use of a modifier in the form of release-active AgNO.sub.3 together with the ligand gave an even greater increase in this indicator compared to the reference values.

Conclusion

[0186] An increase in the proportion of the superconducting phase in the sample volume improves the properties of superconducting screens and magnetic suspensions made on its basis. The stability of the trapped magnetic flux increases, the shielding time constant increases, etc.

Example 12

Measurement of the Imaginary Part of Magnetic Susceptibility

[0187] The absorption of the energy of the electromagnetic field by substance at a given frequency can be characterized by the imaginary part of magnetic susceptibility ?(?). For a coil with a core made of the material under test, the following simple relationship can be introduced:

[00001]$1/Q=1/Q_0+1/Q_s,$

[0188] where 1/Q is the overall loss in the inductor with a core, 1/Q.sub.0 is the loss in the inductor without a core, 1/Qs is the loss in the core, Q.sub.o,s is the Q factor of the measuring coil without (0) and with the sample (s).

[0189] For the operational frequencies of the coil (such that radiation losses and inter-turn capacitance can be neglected, f=?/2?=1-100 kHz) Q.sub.0=L.Math.?/R. Where the quality factor of the coil with the core is large (Q>>1), it can be demonstrated that the value of 1/Qs is proportional to the imaginary part of magnetic susceptibility ?(?) and the fraction of the internal volume of the coil occupied by the core material. In the event when the superconductor is placed in the inductance coil, losses will increase in the zone of the superconducting transition (point FF), where an important role is played by the motion of Abrikosov vortices and fluctuations in the superconducting phase fraction, reaching a maximum (point RF, where the length of the electromagnetic wave in the substance becomes comparable to the size of the sample) and then drop sharply (point CR where an external alternating magnetic field is pushed out of the sample).

[0190] The following samples were used for the analysis: [0191] Sample 1: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking, and a mixture of powders after the first baking treated by in-process monitoring before sintering, in-process monitoring; [0192] Sample 2: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking; [0193] Sample 3: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0194] Sample 4: Intact mixture of powdered Y.sub.2O.sub.3, BaO.sub.2, CuO (batch mix) without admixtures, un-processed, prepared according to standard procedure (general supervision).

TABLE-US-00003 TABLE 3 Temperatures characterizing the SC transition obtained from graphs X (T). SC transition # T.sub.CR, K T.sub.RF0, K T.sub.FF, K width, K 1 85.4 87 90.7 5.3 2 85 88 89.7 4.7 3 84.7 88.5 90.4 5.7 4 82.1 86.5 88.3 6.2

Conclusion

[0195] According to the data obtained, in comparison with the reference value (Sample 4), the use of the announced modifier led to an increase in the T.sub.CR T.sub.RF0 T.sub.FF values, while Sample 2 demonstrated the minimum width of the SC transition, which characterizes the required abrupt SC transition.

[0196] An increase in the superconducting transition temperature and a decrease in its width have a beneficial effect on practically all possible applications of this superconductor.

Example 13

Measurement of the Critical Current Density

[0197] Measurement of the Critical Current Density of Samples by their Current-Voltage Characteristics

[0198] The following samples were used for the analysis: [0199] Sample 1: A mixture of powders (batch mix) treated with RA mix batch of Y.sub.2O.sub.3, BaO.sub.2, CuO composition (C12C30C50) before the primary baking; [0200] Sample 2: A mixture of powders (batch mix) treated with RA AgNO.sub.3 (C12C30C50); [0201] Sample 3: A mixture of powders with admixture of AgNO.sub.3 (batch mix) treated with RA AgNO.sub.3 (C12C30C50);

[0202] Sample 4: Intact mixture of powdered Y.sub.2O.sub.3, BaO.sub.2, CuO (batch mix) without admixtures, un-processed, prepared according to standard procedure (general supervision).

[0203] The density of the intergranular critical current j.sub.ce of the samples was measured according to the results of the assessment of their current-voltage characteristics in liquid nitrogen. In this case, the j.sub.ce value was measured according to the criterion of 1 ?V/cm. According to this criterion, the current density at which a sample displays a voltage of 1 ?V/cm, is taken as j.sub.ce. To expand the range of the measured j.sub.ce in the middle part of the sample under examination, it was narrowed by grinding with a diamond file. The research results are shown in Table 4.

TABLE-US-00004 TABLE 4 Critical current density j.sub.ce measured based on current-voltage characteristic (CVC) according to the criterion of 1 ?V/cm Sample number j.sub.ce, A/cm.sup.2 1 61.5 2 53 3 36 4 43

[0204] The experiment has confirmed an increase in the critical current density j.sub.e with the use of the announced modifier.

Conclusion

[0205] Increasing the critical current is one of the most important factors in the field of obtaining superconducting materials with desired properties. This makes it possible, on the one hand, to reduce the mass of the superconductor in finished products, and on the other hand, to provide large magnetic fields with the same mass of the superconducting material.

Example 14

[0206] Obtaining the RA Modifier Bi.sub.3TiNbO.sub.9
Preparation of Bi.sub.3TiNbO.sub.9 Powder

[0207] To obtain a modified high-temperature piezoelectric of the Bi.sub.3TiNbO.sub.9 (BTN) phase, Bi.sub.2O.sub.3 oxides of chemically pure grade, corresponding to official standard GOST 10210-75 were used for initial components, together with TiO.sub.2 PRETIOX AV1 FG, and Nb.sub.2O.sub.5 of grade 2 corresponding to TU 1763-019-00545484-2000 standard. To purify the reagents from the hygroscopic moisture oxides and impurities, such as carbon dioxide and others, adsorbed during storage, the reagents underwent incineration at 400-800? C. before weighing.

[0208] Mixtures of the composition 3Bi.sub.2O.sub.3.Math.2TiO.sub.2.Math.Nb.sub.2O.sub.5 were prepared for further synthesis of the pure phase of Bi.sub.3TiNbO.sub.9. Then, the mixture was homogenized in distilled water using an Union Process HD/01 attritor. As a result, the size of the component particles decreased to a few micrometers.

[0209] The synthesis of the BTN phase powder from the ready mixture was carried out via solid-phase reactions in an SNOL 12/16 furnace, in air. Homogenized mixtures of Bi.sub.3TiNbO.sub.9 compositions were baked at 1273 K for 6 hours. Two such baking sessions were carried out with intermediate grinding of the resulting synthesis products.

[0210] The procedure yielded polycrystalline samples of Bi.sub.3TiNbO.sub.9 of yellow-brown color, uniform to sight. The synthesized material was ground in an attritor and then dried. The resulting powder had a specific surface area S.sub.sp of 3500 to 6000 cm.sup.2/g.

Obtaining Modifier from Bi.sub.3TiNbO.sub.9 Phase Powder after Baking (p. 1)

[0211] The modifier was obtained via y trituration followed by dilution of the resulting trituration in an aqueous or aqueous-alcoholic solution to obtain a release-active form of Bi.sub.3TiNbO.sub.9 powder after firing, in the form of a mixture of centesimal dilutions C12C30C50. A dry powder of the Bi.sub.3TiNbO.sub.9 phase obtained via firing was used for initial component. Lactose monohydrate was used as neutral carrier in trituration.

[0212] To obtain successive triturations C1-C3 (centesimal scale, 1 unit of the parent substance or the previous trituration (C1 or C2) and 99 units of lactose monohydrate is taken), the following procedure is observed. The required amount of lactose monohydrate is divided into 3 equal portions. The first portion of lactose monohydrate is placed in a porcelain mortar and ground to close the pores of the mortar. Then the entire amount of the dry powdered parent substance is added, and the resulting mixture is ground with effort, after which the powder is raked with a spatula and scraped off the walls of the mortar; this operation is repeated once more. Then the second and the third portions of lactose monohydrate are added sequentially, repeating the above actions with each portion. Thus, trituration C1 is obtained. Then, similar to the above process, C2 trituration is obtained (adding 1 unit of C1 trituration to 99 units of lactose) and C3 trituration (adding 1 unit of C2 trituration to 99 units of lactose).

[0213] The subsequent dilution C4 is obtained from 1 unit of the trituration of C3 and 99 units (centesimal scale) of 25% aqueous solution of ethyl alcohol. These components are thoroughly mixed until smooth, shaking the closed bottle vertically. C5 dilution is obtained from 1 unit of C4 dilution and 99 parts of 25% aqueous solution of ethyl alcohol, thoroughly mixing the indicated components until smooth, shaking vertically. The required degree of dilution is obtained by repeating the previous steps as appropriate.

[0214] Further, to obtain release-active Bi.sub.3TiNbO.sub.9 powder after baking, in the form of a mixture of dilutions, according to this example, C12C30C50, centesimal dilutions are prepared according to the above-described technology until dilution which is 3 steps of centesimal dilutions less than the final solution of C12C30C50. For this dilution, C9, C27 and C47, one unit of each dilution (in this example, the volume ratio is 1:1:1) are put into one container containing 97 units of a 70% aqueous solution of ethyl alcohol (for centesimal dilution). The resulting mixture is then sequentially diluted twice in a ratio of 1 to 100, using 70% aqueous solution of ethyl alcohol at the penultimate stage, and 36% aqueous solution of ethyl alcohol at the last stage, thoroughly mixing these components until smooth, shaking the closed bottle with the resulting solution vertically after each dilution. At the last stage, modifier is obtained, a release-active form of Bi.sub.3TiNbO.sub.9, by diluting the mentioned parent substance by 100.sup.12, 100.sup.30, 100.sup.50 times, which in terms of homeopathic technology corresponds to a mixture of centesimal dilutions C12, C30 and C50.

Example 15

[0215] Obtaining Modified Bi.sub.3TiNbO.sub.9 Piezoceramics Using Conventional Ceramic Processing Technology

[0216] Polycrystalline powders of Bi.sub.3TiNbO.sub.9 phase (80 g) obtained according to p. 1 of Example 14 were further moistened with modifier (25 ml), a release-active form of a piezoelectric material of the Bi.sub.3TiNbO.sub.9 phase obtained after baking, in the form of a mixture of centesimal dilutions C12C30C50, obtained according to p. 1.2 of Example 14. A solution was prepared and the powder was moistened in a laminar flow chamber in a clean environment taking all appropriate measures to prevent the risk of sample contamination. The obtained wetted powders were dried at +35? C. for at least 6 hours until the liquid visibly evaporated.

[0217] The resulting modifier-moistened Bi.sub.3TiNbO.sub.9 phase powders were molded into cylindrical billets 10 mm in diameter and 1 to 2 mm thick. Before molding, the powders were ground in mortars together with ?1 wt % of 5% aqueous solution of polyvinyl alcohol (PVA) for better homogenization. Molding was performed under single-axis 200 kg/cm.sup.2 pressure, using a Shimadzu hydraulic press and a set of appropriate molds.

[0218] The billets obtained after molding were sintered in air in a SNOL 12/16 furnace at 1413K for 4 hours.

[0219] The procedure yielded ceramic samples in the form of ?10?(1-2) mm cylindrical discs. The density of the resulting ceramics measured by dividing the mass of the tablet by its volume, was ? 80(5)% of the maximum possible density (non-porous ceramics), also called X-ray density.

Example 16

[0220] Obtaining Modified Bi.sub.3TiNbO.sub.9 Piezoceramics Using Hot Extrusion

[0221] Polycrystalline powders of Bi.sub.3TiNbO.sub.9 phase (80 g) obtained according to p. 1 of Example 14 were further moistened with modifier (25 ml), a release-active form of a piezoelectric material of the Bi.sub.3TiNbO.sub.9 phase obtained after baking, in the form of a mixture of centesimal dilutions C12C30C50, obtained according to p. 2 of Example 14. A solution was prepared and the powder was moistened in a laminar flow chamber in a clean environment, taking all appropriate measures to prevent the risk of sample contamination.

[0222] The resulting wetted Bi.sub.3TiNbO.sub.9 powders were dried at 150? C. for 4 hours after which they were sieved through a 700 ?m sieve. Next, press powders were prepared from the powders by introducing 5 mass percent of 5% aqueous PVA solution, thorough mixing and sifting through a sieve.

[0223] The resulting press powder was loaded into PG-10 press-form to form briquettes under the pressure of 150 MPa. Cylindrical billets ?50?10 mm were obtained.

[0224] Then the resulting billet was sintered under pressure on a UGP-2 hot pressing unit using an aluminum oxide filling at a temperature of 1423 K and a pressure of 250-300 kg/cm.sup.2 for 1 to 4 hours to obtain modified high-temperature piezoceramic phase of Bi.sub.3TiNbO.sub.9.

[0225] The density of the synthesized ceramic billet measured by the Archimedes method on a high-accuracy balance was 97 to 99% of its X-ray density.

[0226] The samples used in further studies were obtained as described above: [0227] 1) Samples of Bi.sub.3TiNbO.sub.9 phase powder (Example 14, p. 1), treated with RA phase of Bi.sub.3TiNbO.sub.9 obtained after baking (Example 14, p. 2); [0228] 2) Samples of Bi.sub.3TiNbO.sub.9 phase powder treated with RA lactose; [0229] 3) Samples of Bi.sub.3TiNbO.sub.9 phase powder treated with 36.7% aqueous ethanol solution.

[0230] Un-treated Bi.sub.3TiNbO.sub.9 powder was used for control samples in the research.

[0231] For the electrophysical measurements described in Examples 17 and 18, plates were cut out from the cylindrical billets obtained after hot pressing perpendicular to the basal planes (or, similarly, parallel to the direction of the pressure). The size of the resulting plates was 0.5?5?5 mm. After cutting, they were washed in an ultrasonic bath in distilled water and dried at a temperature of 673 K. On the BTN plates, circular conductive electrodes ?2.5 mm in diameter were imposed by burning on Ag/Pd conductive paste (70/30%) at 1023 to 1223K.

Example 17

Results of X-Ray Phase Analysis of all Obtained Samples

[0232] Bi.sub.3TiNbO.sub.9 samples after their hot-pressing synthesis were subject to X-ray phase analysis (XPA), on an automated X-ray diffractometer DRON-4 using filtered copper radiation and Ge crystal powder as an internal standard (FIG. 4). Repeated measurements of the diffraction patterns showed that the positions of the corresponding Bragg reflection angles 2? coincide, with an accuracy of ?(0.01-0.02).

[0233] Diffraction patterns of the samples, by their positions and reflection intensities, correspond to the literature data on the Bi.sub.3TiNbO.sub.9 phase [Powder Diffraction files of the International Centre for Diffraction Data (ICDD) (1999)]. All reflections of diffraction patterns of the sintered samples refer to Bi.sub.3TiNbO.sub.9 phase with a layered perovskite-like structure, with no significant impurity reflections observed. In this regard, it can be concluded that the synthesized samples are practically single-phase, they consist of a double-layered (n=2) Aurrivillius phase of Bi.sub.3TiNbO.sub.9.

[0234] The parameters of the rhombic unit cell of the phase obtained during the indication correspond to the literature data on this phase. The manifestation of intense reflections from the (001) planes from the cuts perpendicular to the hot pressing axis, and a significant weakening (or absence) of these reflections on the cuts perpendicular to them indicates that the hot pressed samples are planar textures in which the (001) planes of crystallites are oriented parallel the basal planes of the tablets (perpendicular to the pressure direction during hot pressing).

Example 18

Results of Measurements of the d.SUB.33 .Piezoelectric Coefficient

Sample Polarization

[0235] Polarization was performed in a compressed air installation by applying a 10 kV/mm electric field to the samples at a temperature of 200? C., for 15 to 30 minutes, and cooling to 50-60? C. under the field. This mode turned out to be optimal for polarization of Bi.sub.3TiNbO.sub.9 ceramics.

Measurement of d.SUB.33 .Piezoelectric Modulus

[0236] The d.sub.33 piezoelectric module was measured by the method of oscillating mechanical load on a d.sub.33 meter YE2730A (APC, USA) at a frequency of 110 Hz, under room temperature, on pre-polarized ceramic samples.

[0237] The results of the measurements are presented in Table 6. In addition, each value given in the table is an average of 10 measurements performed on the same sample.

TABLE-US-00005 TABLE 6 Values of d.sub.33 piezoelectric coefficient for sections 1 of hot-pressed Bi.sub.3TiNbO.sub.9 samples of different series (n) Series 2 Series 3 Series 4 Series 1 Bi.sub.3TiNbO.sub.9 Bi.sub.3TiNbO.sub.9 Bi.sub.3TiNbO.sub.9 Un-treated powder powder powder (un- treated treated with treated modified) with RA with RA Bi.sub.3TiNbO.sub.9 36.7% Bi.sub.3TiNbO.sub.9 lactose powder ethanol (C12C30C50) (C12C30C50) d.sub.33 piezoelectric 10.1(?0.2) 10.6(?0.4) 12.7(?1.1) 10.7(?0.2) coefficient, pC/N (? value of the last character)

[0238] It is worth pointing out that the average d.sub.33 values of the samples of series 3 (12.7 pC/N) are 25% higher than the average d.sub.33 values of the unmodified samples.

[0239] Thus, the use of the declared modifier leads to an increase in one of the main parameters characterizing the piezoelectric activity of the sample under analysis.

Conclusion

[0240] An increase in the piezoelectric coefficient of a substance can significantly improve all the main characteristics of a piezoelectric transducer based on it, that is, to reduce the mass and, accordingly, the response delay of the transducer, and to increase its sensitivity and dynamic range. This is especially important in the case of high-temperature piezoelectrics like Bi.sub.3TiNbO.sub.9 used to manufacture sensors for monitoring the parameters of propulsion systems.

Example 19

Measurement of Pyroelectric Coefficient

[0241] Pyroelectric coefficient p.sup.(X)=(?P.sub.s/?T)x (where P.sub.s is spontaneous polarization and X is mechanical tension) was determined by the quasi-static method, basing on the results of the temperature dependence measurements of pyroelectric current I.sub.p induced by alterations of sample temperature dT/dt:

[00002]$I_p=\mathrm{dq}/\mathrm{dt}=d\left(S?\right)/\mathrm{dt}={\mathrm{SdP}}_s/\mathrm{dt}=S\left(d{P}_s/\mathrm{dT}\right)/\left(\mathrm{dT}/\mathrm{dt}\right)=S{p}^{\left(X\right)}/\left(\mathrm{dT}/\mathrm{dt}\right),$

[0242] q is pyroelectric charge arising on the electrodes upon variation of the temperature of the sample, and Q is the surface density of this charge, equal to P.sub.s.

[0243] Pyroelectric currents were measured with a V7-30 electrometer; the temperature variation rate was set equal to 0.3 K/s with a temperature meter regulating the ITR 2523 (OOO NPP Dana-Term, Russia).

[0244] For measurements, we used personal Pentium-based computers, a modular data acquisition system of LTR type by L-CARD Company, under the control of the LabView software package.

[0245] The findings are presented in Table 7. Each value given in the table is the average of 10 measurements of the same sample.

TABLE-US-00006 TABLE 7 Values of the pyroelectric coefficient p.sup.? of different series of BTN samples Un-treated Bi.sub.3TiNbO.sub.9 powder treated (un-modified) with RA Bi.sub.3TiNbO.sub.9 Bi.sub.3TiNbO.sub.9 powder (C12C30C50) Pyroelectric coefficient p.sup.? 0.75(?3) 0.96(?6) pC/(cm.sup.2 .Math. K) (?value of the last character)

[0246] Bi.sub.3TiNbO.sub.9 modified according to the present invention demonstrates a 28% change in pyroelectric coefficient in comparison with the unmodified sample.

Conclusion

[0247] An increase in the pyroelectric coefficient enables nearly proportional increase of the output signal (electrical voltage), without changing the design of the pyroreceiver, or proportional reduction of the pyroreceiver area at a given level of the output signal. In the first case, there is increase in the transducer sensitivity, and in the second case, there is decrease in its dimensions and mass.

[0248] According to the findings, modified ceramics has certain promising potential for high-temperature applications, in particular, as electro-acoustic transducers and sensors to be used under high temperatures. The application of the claimed invention, therefore, makes it possible to expand the field of application of ceramics. Its relative ease of implementation makes it attractive for use in various fields of science and technology.