A flaky template with ferromagnetic properties, its preparation method and application

Abstract

The present invention discloses a sheet template with ferromagnetic properties, its preparation method and applications. The chemical formula of the sheet template is AB 1‑ x B1 4x / 3 O3 or AB 1‑x (B1B2) x O3, 0

Description

Technical Field

[0001] The present invention belongs to the fields of magnetism, nanometer and topochemical materials, and relates to a flaky template with ferromagnetic properties, a preparation method thereof and an application thereof. Background Art

[0002] The existing methods for preparing ceramic templates are as follows: (1) Topochemical template growth technology: The topochemical method is also called crystal conversion method or ion coordination chemistry method. Generally, the nature of a chemical reaction depends on the chemical properties of reactants, that is, by designing a reaction route, a precursor crystal with an easily obtained flaky structure is first prepared, and then based on the structure and shape of the precursor crystal, the ions in the crystal are replaced to obtain a specific flaky compound;

[0003] (2) Molten salt technology: Since a low melting point salt is used as a reaction medium and there is a liquid phase in the synthesis process, the reactants have a certain solubility in it, greatly accelerating the diffusion rate of ions and enabling the reactants to achieve atomic-scale mixing in the liquid phase, so that the reaction is transformed from a solid-solid reaction to a solid-liquid reaction. Compared with the conventional solid-phase method, this method has the advantages of simple process, low synthesis temperature, short heat preservation time, uniform chemical composition of the synthesized powder, good crystal morphology, high phase purity, etc. In addition, the salt is easy to separate and can also be reused;

[0004] (3) Hydrothermal reaction technology: A synthesis reaction is carried out by using the properties of water as a reaction medium in the supercritical state and the special properties of reactants under high temperature and high pressure hydrothermal conditions. Under hydrothermal conditions, water can act as a chemical component and participate in the reaction, being both a solvent and a mineralizer and also a pressure transmission medium; by participating in dialysis reactions and controlling physical and chemical factors, etc., the formation and modification of inorganic compounds are realized. It can prepare single-component microcrystals and can also prepare special compound powders of two-component or multi-component. It overcomes the inevitable hard agglomeration in some high-temperature preparations, and has the characteristics of fine powder (nanometer level), high purity, good dispersibility, uniformity, narrow distribution, no agglomeration, good crystal form, controllable shape and beneficial to environmental purification, etc.

[0005] The prior art can also prepare flaky barium titanate, strontium titanate templates, sodium potassium niobate templates, lead titanate templates, etc., but almost all of the existing templates do not show ferromagnetic properties and cannot be regulated by a magnetic field, which limits the application of the templates in ferromagnetism. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a flaky template with ferromagnetic properties, and the chemical formula is AB 1-x B1 4x / 3 O3 or AB 1-x (B1B2) xO3, where 0 < x < 1, A is barium, strontium, lead, calcium or magnesium, B is titanium or zirconium, B1 is at least one of iron, cobalt and nickel elements, and B2 is at least one of niobium, tantalum and vanadium; a flaky template with ferromagnetic properties is obtained.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a flaky template with ferromagnetic properties, the chemical formula of which is AB 1-x B1 4x / 3 O3 or AB 1-x (B1B2) x O3, where 0 < x < 1, A is barium, strontium, lead, calcium or magnesium, B is titanium or zirconium, B1 is at least one of iron, cobalt and nickel elements, and B2 is at least one of niobium, tantalum and vanadium;

[0008] Weigh the B-site element compound, bismuth source, B1-site element compound, and B2-site element compound according to the stoichiometric ratio, and weigh 0.5 - 10 times the total weight of the above raw materials of KCl or NaCl for mixing to obtain mixture I.

[0009] Keep the mixture I in a high-temperature environment of 800 - 1200 °C for 1 - 8 h to obtain the molten salt mixed product II. Wash the molten salt mixed product II with water to obtain the precursor, and then mix the precursor with the A-site element compound and 1 times the weight of KCl or NaCl to obtain mixture III. Calcinate mixture III at 800 - 1200 °C for 1 - 8 hours to obtain the molten salt mixed product IV. Wash and acid-soak the molten salt mixed product IV to obtain a flaky template containing elements such as iron, cobalt, and nickel.

[0010] The A-site element compound is a barium source compound, a strontium source compound, a magnesium source compound, a calcium source compound or a lead source compound. The barium source compound is Ba(OH)2, BaCO3, Ba(NO3)2 or BaO; the strontium source compound is Sr(OH)2, SrCO3, Sr(NO3)2 or SrO; the magnesium source compound is Mg(OH)2, MgCO3, Mg(NO3)2 or MgO; the calcium source compound is Ca(OH)2, CaCO3, Ca(NO3)2 or CaO; the lead source is Pb(OH)2, PbCO3, Pb(NO3)2 or PbO.

[0011] The compound of the B-site element is titanium dioxide or zirconium dioxide.

[0012] The B1-site element compound is an iron source compound, a cobalt source compound or a nickel source compound; the iron source compound is Fe(OH)3, Fe2(CO3)3, Fe(NO3)3, Fe2O3 or Fe3O4, the nickel source compound is Ni(OH)3, Ni2(CO3)3, Ni(NO3)3, Ni2O3 or Ni3O4, and the cobalt source compound is Co(OH)3, Co2(CO3)3, Co(NO3)3, Co2O3 or Co3O4.

[0013] The B2-site element compound includes niobium pentoxide, tantalum pentoxide and vanadium pentoxide.

[0014] The B-site element compound, bismuth source, M-site element compound, N-site element compound and salt are mixed evenly by wet ball milling and dried, and after drying, they are sieved through a 40-mesh sieve.

[0015] A ferromagnetic flake template is obtained based on the preparation method described in the present invention. The length of the template is between 3 and 25 microns, the thickness is 0.2 ± 2 microns, and the aspect ratio is greater than 8.

[0016] Regarding the application of the ferromagnetic flake template described in the present invention, when it is used to prepare piezoelectric textured ceramics, the ferromagnetic flake template is arranged directionally by applying an external magnetic field.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] (1) The template has ferromagnetic properties. By introducing elements such as iron, cobalt, and nickel, the template that originally did not have ferromagnetic properties shows ferromagnetic properties. In addition, the elements at the A-site can be changed, making this template more versatile;

[0019] (2) The magnetic strength of the template is controllable. By changing the types and contents of elements such as iron, cobalt, and nickel at the B-site, the control of magnetic strength can be achieved;

[0020] (3) The arrangement of the template is controllable. By regulating the external magnetic field, the direction and displacement of the template are controlled. In textured ceramics, by controlling the direction of the electric field, the orientation of the magnetic template is controlled, so as to obtain a perfectly oriented textured ceramic, and then higher performance is obtained. In addition, the number of templates used in textured ceramics can be reduced. Description of the Drawings

[0021] Figure 1 For Bi4Ti 2.1 Ni 1.2 O 12 XRD pattern of the precursor.

[0022] Figure 2 For Bi4Ti 2.1 Ni 1.2 O12 SEM images of the precursor

[0023] Figure 3 For BaTi 0.7 Ni 0.4 XRD patterns of the BaTi

[0024] Figure 4 For BaTi 0.7 Ni 0.4 SEM images of the BaTi

[0025] Figure 5 For CaTi 0.8 (Fe 1 / 2 Nb 1 / 2 ) 0.2 XRD patterns of the CaTi Specific embodiments

[0026] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] In the present invention, if there is no special description, all the embodiments and preferred implementation methods mentioned in the present invention can be combined with each other to form a new technical solution.

[0028] In the present invention, if there is no special description, all the technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0029] Example 1 The preparation method of the BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template includes the following steps:

[0030] The first step: Preparation of the precursor powder

[0031] (1) Using high-purity Bi2O3, TiO2, Fe2O3, Nb2O5 as raw materials, according to the chemical stoichiometric ratio of Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Weigh the materials, where x can take non-zero values from 0 to 1, and here it is 0.1;

[0032] (2) Mix the above raw materials with an equal mass of salt by wet ball milling, and then dry them. The salt is a mixture of NaCl and KCl with equal molar amounts, and the total mass of the salt is 1.5 times that of the raw materials.

[0033] (3) Pass the dried powder in step (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 800 °C for 5 hours.

[0034] (4) Wash the salt in the molten salt reactant in (3) repeatedly with hot deionized water until it is washed clean to obtain Bi4Ti with good dispersibility and uniform size. 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 precursor powder.

[0035] The second step: Preparation of BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template

[0036] (1) Wet-mix the Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 precursor powder obtained in the second step with BaCO3 and salt with a total mass equivalent to the sum of the masses of the former two for 2 hours. The salt is a mixture of NaCl and KCl with equal molar amounts, and the total mass of the salt is 1.5 times that of the raw materials.

[0037] (2) Dry the mixture in (1) in an oven, and then carry out a molten salt reaction in a muffle furnace. The reaction conditions are 4 hours at 1000 °C.

[0038] (3) Wash the molten salt reactant in (2) repeatedly with hot ultrapure water. After the salt is washed clean, a mixture of BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 and Bi2O3 is obtained.

[0039] (4) Wash the mixture in (3) alternately with a dilute acid solution and ultrapure water until Bi2O3 in the mixture is completely removed to obtain a BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template.

[0040] This template contains Fe elements and has magnetism. In addition, the x value in the template can be adjusted to control the content of Fe elements, thereby controlling the strength of the magnetism of the template.

[0041] Example 2 The BaTi with ferromagnetic properties described in the present invention 1-x (Fe 1 / 2 Nb 1 / 2 ) x The preparation method of the O3 flake template includes the following steps:

[0042] The first step: Preparation of precursor powder

[0043] (1) Using high-purity Bi2O3, TiO2, Fe2O3, and Nb2O5 as raw materials, according to Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Weigh the materials according to the stoichiometric ratio, where x can take non-zero values between 0 and 1, and here it is 0.1;

[0044] (2) Wet ball mill and mix the above raw materials with an equal mass of salt, and then dry them. The salt is KCl, and the mass of the salt is 1 time that of the raw materials;

[0045] (3) Pass the dried powder in step (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 1050 °C for 5 hours;

[0046] (4) Repeatedly wash the salt in the molten salt reactant in (3) with hot deionized water until it is washed clean, and obtain Bi4Ti with good dispersibility and uniform size 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Precursor powder.

[0047] The second step: Preparation of the BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template

[0048] (1) Wet-mix the Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Precursor powder obtained in the second step, BaCO3, and a salt equivalent to the total mass of the first two for 2 - 5 hours. The salt is one or both of NaCl and KCl;

[0049] (2) Dry the mixture in (1) in an oven, and then conduct a molten salt reaction in a muffle furnace. The reaction conditions are 5 hours at 1020 °C;

[0050] (3) Wash the molten salt reactants in (2) repeatedly with hot ultrapure water. After the salt is cleaned, obtain a mixture of BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 and Bi2O3;

[0051] (4) Wash the mixture in (3) alternately with dilute acid solution and ultrapure water until Bi2O3 in the mixture is completely removed, obtaining a BaTi 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template.

[0052] This kind of template contains Fe element and has magnetism. In addition, the x value in the template can be adjusted to control the content of Fe element, so as to control the strength of the template magnetism.

[0053] Example 3 The preparation method of the Ba 1-y Sr y Ti 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template with ferromagnetic properties includes the following steps:

[0054] The first step: Preparation of precursor powder

[0055] (1) Using high-purity Bi2O3, TiO2, Fe2O3, Nb2O5 as raw materials, according to the stoichiometric ratio of Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Weigh the materials. Here, x can take non-zero values from 0 to 1, and here it is 0.25;

[0056] (2) Mix the above raw materials with an equal mass of salt by wet ball milling, and then dry them. The salt is a mixture of equimolar amounts of NaCl and KCl, and the total mass of the salt is 5 times that of the raw materials;

[0057] (3) Pass the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and conduct a molten salt reaction at 1150 °C for 2 hours;

[0058] (4) Wash the salt in the molten salt reactants in (3) repeatedly with hot deionized water until it is cleaned, obtaining a well-dispersed and uniform-sized Bi4Ti3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 Precursor powder.

[0059] Step 2: Ba 1-y Sr y Ti 1-x (Fe 1 / 2 Nb 1 / 2 ) x Preparation of Ba

[0060] (1) Wet-mix the Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 precursor powder obtained in Step 2, SrCO3, BaCO3, and salts with a total mass equivalent to the sum of the first two for 2 hours, where the equimolar mixture of NaCl and KCl has a total salt mass 5 times that of the raw materials;

[0061] (2) Dry the mixture obtained in (1) in an oven and then perform a molten salt reaction in a muffle furnace under the reaction conditions of 1100 °C for 2 hours;

[0062] (3) Repeatedly wash the molten salt reactant in (2) with hot ultrapure water until the salt is cleaned, obtaining a mixture of Ba 1- y Sr y Ti 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 and Bi2O3;

[0063] (4) Wash the mixture in (3) alternately with dilute acid solution and ultrapure water until the Bi2O3 in the mixture is completely removed, obtaining a Ba 1-y Sr y Ti 1-x (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template, y = 0.5;

[0064] This template contains Fe elements and has ferromagnetic properties. In addition, the x value in the template can be adjusted to control the content of Fe elements, thereby controlling the strength of the template's magnetism.

[0065] Example 4 The ferromagnetic BaTi (1-x-y) (Fe 1 / 2 Nb 1 / 2 ) x (Co1 / 2 Nb 1 / 2 ) y The preparation method of the NbO3 flake template comprises the following steps:

[0066] The first step: Preparation of the precursor powder

[0067] (1) Using Bi2O3, TiO2, Co2O3, Fe2O3, Nb2O5 as raw materials, according to Bi4Ti 3(1-x-y) (Fe 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2Nb 1 / 2 ) 3y O 12 Weigh the materials according to the stoichiometric ratio, where x and y can take non-zero values between 0 and 1, and x + y ≤ 1. Here, x is 0.15 and y is 0.1;

[0068] (2) Mix the above raw materials with an equal mass of salt by wet ball milling, and then dry them. The salt is NaCl, and the mass of the salt is 6 times that of the raw materials;

[0069] (3) Pass the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 1000 °C for 2 hours;

[0070] (4) Wash the salt in the molten salt reactant in (3) repeatedly with hot deionized water until it is washed clean to obtain a well-dispersed and uniform-sized Bi4Ti 3(1-x-y) (Fe 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2 Nb 1 / 2 ) 3y O 12 precursor powder.

[0071] The second step: Preparation of the BaTi (1-x-y) (Fe 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 flake template

[0072] (1) The Bi4Ti finally obtained in the second step 3(1-x-y) (Fe 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2 Nb 1 / 2 ) 3y O 12The precursor powder is wet-mixed with BaCO3 and a salt having a total mass equivalent to that of the first two for 4 hours. The salt is a mixture of equimolar amounts of NaCl and KCl, and the total mass of the salt is 10 times that of the raw materials.

[0073] (2) The mixture in (1) is dried in an oven and then subjected to a molten salt reaction in a muffle furnace under the reaction conditions of 1100 °C for 7 hours.

[0074] (3) The molten salt reactant in (2) is repeatedly washed with hot ultrapure water, and after the salt is washed clean, a mixture of BaTi (1-x-y) (Fe 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 and Bi2O3 is obtained.

[0075] (4) The mixture in (3) is alternately washed with a dilute acid solution and ultrapure water until the Bi2O3 in the mixture is completely removed, and a BaTi (1-x-y) (Fe 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 flake template is obtained.

[0076] This kind of template contains Fe and Co elements and has magnetism. The x and y values in the template can be regulated to control the contents of Fe and Co elements, thereby achieving the control of the magnetic strength of the template.

[0077] Example 5 The preparation method of the BaTi (1-x-y) (Ni 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 flake template with ferromagnetic properties includes the following steps:

[0078] The first step: Preparation of the precursor powder

[0079] (1) Using Bi2O3, TiO2, Co2O3, Ni2O3, Nb2O5 as raw materials, according to Bi4Ti 3(1-x-y) (Ni 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2Nb 1 / 2 ) 3y O 12Stoichiometric weighing of materials, where x and y can take non-zero values between 0 and 1, and x + y ≤ 1. Here, x = 0.2 and y = 0.15;

[0080] (2) Wet ball mill the above raw materials with an equal mass of salt, and then dry them. The salt is a mixture of NaCl and KCl in equal molar amounts, and the total mass of the salt is 6 times that of the raw materials;

[0081] (3) Sieve the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 980 °C for 6 hours;

[0082] (4) Repeatedly wash the salt in the molten salt reactant in (3) with hot deionized water until it is clean, to obtain a well-dispersed and uniform-sized Bi4Ti 3(1-x-y) (Ni 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2 Nb 1 / 2 ) 3y O 12 precursor powder.

[0083] The second step: Preparation of BaTi (1-x-y) (Ni 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 flake template

[0084] (1) Wet mix the Bi4Ti 3(1-x-y) (Ni 1 / 2 Nb 1 / 2 ) 3x (Co 1 / 2 Nb 1 / 2 ) 3y O 12 precursor powder obtained in the second step with BaCO3 and a salt with a total mass equivalent to the sum of the previous two. The salt is a mixture of NaCl and KCl in equal molar amounts, and the total mass of the salt is 6 times that of the raw materials;

[0085] (2) Dry the mixture in (1) in an oven, and then carry out a molten salt reaction in a muffle furnace. The reaction conditions are 930 °C for 6 hours;

[0086] (3) Repeatedly wash the molten salt reactant in (2) with hot ultrapure water. After the salt is washed clean, obtain BaTi (1-x-y) (Ni 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb1 / 2 ) y Mixture of O3 and Bi2O3;

[0087] (4) Wash the mixture in (3) alternately with dilute acid solution and ultrapure water until Bi2O3 in the mixture is completely removed, obtaining BaTi (1-x-y) (Ni 1 / 2 Nb 1 / 2 ) x (Co 1 / 2 Nb 1 / 2 ) y O3 flake template.

[0088] This kind of template contains Ni and Co elements and has ferromagnetic properties. In addition, the x and y values in the template can be adjusted to control the content of Ni and Co elements, thereby controlling the strength of the template magnetism.

[0089] Example 6 Preparation method of the CaTi (1-x) (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template includes the following steps:

[0090] First step: Preparation of precursor powder

[0091] (1) Using Bi2O3, TiO2, Fe2O3, Nb2O5 as raw materials, weighing according to the chemical stoichiometric ratio of Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 , where x is 0.2;

[0092] (2) Mix the above raw materials with an equal mass of salt by wet ball milling, and then dry, where the salt is a mixture of equimolar amounts of NaCl and KCl, and the total mass of the salt is 3 times that of the raw materials;

[0093] (3) Pass the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 1100 °C for 5 hours;

[0094] (4) Wash the salt in the molten salt reactant in (3) repeatedly with hot deionized water until it is washed clean, obtaining Bi4Ti with good dispersibility and uniform size 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 precursor powder.

[0095] Second step: CaTi (1-x) (Fe1 / 2 Nb 1 / 2 ) x Preparation of O3 Flake Template

[0096] (1) Wet-mix the Bi4Ti 3(1-x) (Fe 1 / 2 Nb 1 / 2 ) 3x O 12 precursor powder with CaCO3 and a salt with a total mass equivalent to the sum of the masses of the former two for 5 hours, where the salt is a mixture of equimolar amounts of NaCl and KCl, and the total mass of the salt is 3 times that of the raw materials;

[0097] (2) Dry the mixture in (1) in an oven and then carry out a molten salt reaction in a muffle furnace under the reaction conditions of 1150 °C for 2 hours;

[0098] (3) Wash the molten salt reactant in (2) repeatedly with hot ultrapure water. After the salt is washed clean, a mixture of CaTi (1-x) (Fe 1 / 2 Nb 1 / 2 ) x O3 and Bi2O3 is obtained;

[0099] (4) Wash the mixture in (3) alternately with a dilute acid solution and ultrapure water until the Bi2O3 in the mixture is completely removed, obtaining a CaTi (1-x) (Fe 1 / 2 Nb 1 / 2 ) x O3 flake template.

[0100] This template contains Fe elements and has ferromagnetic properties. In addition, the x value in the template can be adjusted to control the content of Fe elements, thereby achieving control of the magnetic strength of the template. Refer to Figure 5 , the XRD pattern of the CaTi 0.8 (Fe 1 / 2 Nb 1 / 2 ) 0.2 O3 magnetic template. It can be seen from the figure that the powder shows a pure perovskite phase structure, and from the orientation result, the surface of the template has a strong <001> orientation.

[0101] Example 7 The preparation method of the MgTi (1-x-y) Fe 4x / 3 Ni 4y / 3 O3 flake template with ferromagnetic properties of the present invention includes the following steps:

[0102] The first step: Preparation of precursor powder

[0103] (1) Using Bi2O3, TiO2, Ni2O3, and Fe2O3 as raw materials, weigh the materials according to the stoichiometric ratio of Bi4Ti 3(1-x-y) Fe 4x Ni 4y O 12 , where x and y can take non-zero values between 0 and 1. Here, x is 0.2 and y is 0.5;

[0104] (2) Mix the above raw materials with an equal mass of salt by wet ball milling, and then dry them. The salt is KCl, and the mass of the salt is 4 times that of the raw materials;

[0105] (3) Sieve the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and carry out a molten salt reaction at 1020 °C for 2 hours;

[0106] (4) Repeatedly wash the salt in the molten salt reactant in (3) with hot deionized water until it is clean, to obtain a well-dispersed and uniform-sized Bi4Ti 3(1-x-y) Fe 4x Ni 4y O 12 precursor powder.

[0107] Second step: Preparation of MgTi (1-x-y) Fe 4x / 3 Ni 4y / 3 O3 flake template

[0108] (1) Wet-mix the Bi4Ti 3(1-x) Ni 4x O 12 precursor powder obtained in the second step, MgCO3, and a salt with a total mass equivalent to the sum of the first two for 3 hours. The salt is KCl, and the mass of the salt is 4 times that of the raw materials;

[0109] (2) Dry the mixture in (1) in an oven, and then carry out a molten salt reaction in a muffle furnace. The reaction conditions are 2 hours at 1100 °C;

[0110] (3) Repeatedly wash the molten salt reactant in (2) with hot ultrapure water. After the salt is washed clean, obtain a mixture of MgTi (1-x-y) Fe 4x / 3 Ni 4y / 3 O3 and Bi2O3;

[0111] (4) Alternately wash the mixture in (3) with a dilute acid solution and ultrapure water until the Bi2O3 in the mixture is completely removed, to obtain a MgTi (1-x-y) Fe 4x / 3 Ni 4y / 3 O3 flake template.

[0112] This kind of template contains Ni and Fe elements and has ferromagnetic properties. In addition, the x and y values in the template can be adjusted to control the contents of Ni and Fe elements, thereby controlling the strength of the magnetism of the template.

[0113] Example 8 The BaTi with ferromagnetic properties described in the present invention (1-x) Ni 4x / 3 The preparation method of the O3 flake template includes the following steps:

[0114] The first step: Preparation of precursor powder

[0115] (1) Using Bi2O3, TiO2, and Ni2O3 as raw materials, weighing according to the stoichiometric ratio of Bi4Ti 3(1-x) Ni 4x O 12 where x is 0.3;

[0116] (2) Wet ball-milling and mixing the above raw materials with an equal mass of salt, and then drying, where the salt is an equimolar mixture of NaCl and KCl, and the mass of the salt is 1 time that of the raw materials;

[0117] (3) Passing the dried powder in (2) through a 40-mesh sieve to obtain a uniform and well-dispersed powder, and performing a molten salt reaction at 1090 °C for 6 hours;

[0118] (4) Repeatedly washing the salt in the molten salt reactant in (3) with hot deionized water until it is washed clean, to obtain a Bi4Ti with good dispersibility and uniform size 3(1-x) Ni 4x O 12 precursor powder.

[0119] The second step: Preparation of the BaTi (1-x) Ni 4x O3 flake template

[0120] (1) Wet-mixing the Bi4Ti finally obtained in the second step 3(1-x) Ni 4x O 12 precursor powder, BaCO3, and a salt with a total mass equivalent to the sum of the masses of the former two for 3 hours, where the salt is an equimolar mixture of NaCl and KCl, and the mass of the salt is 1 time that of the raw materials;

[0121] (2) Drying the mixture in (1) in an oven, and then performing a molten salt reaction in a muffle furnace, with the reaction conditions being 2 hours at 990 °C;

[0122] (3) Repeatedly washing the molten salt reactant in (2) with hot ultrapure water, and obtaining a mixture of BaTi (1-x) Ni 4x O3 and Bi2O3 after the salt is washed clean;

[0123] (4) Wash the mixture in (3) alternately with dilute acid solution and ultrapure water until the Bi2O3 in the mixture is completely removed, obtaining BaTi (1-x) Ni 4x O3 flake template.

[0124] Reference Figure 1 , the precursor Bi4Ti 2.1 Ni 1.2 O 12 XRD pattern of, it can be seen from the figure that the powder shows a pure bismuth titanate phase structure and there is no second-phase structure, indicating that the Ni element has been well solid-solved into the lattice of bismuth titanate; reference Figure 3 , BaTi 0.7 Ni 0.4 O3 magnetic template's oriented XRD pattern, it can be seen from the figure that the powder shows a pure perovskite phase structure, and from the orientation result, the surface of this template has a strong <001> orientation, reference Figure 2 , the precursor Bi4Ti 2.1 Ni 1.2 O 12 SEM photograph of, it can be seen from the figure that the powder shows a flaky structure, similar to the layered structure of bismuth titanate, and the diameter of this powder flake is between 10 - 30 μm, reference Figure 4 , BaTi 0.7 Ni 0.4 SEM photograph of O3 magnetic template, it can be seen from the figure that the powder shows a flaky structure, and the radial size is between 5 - 15 μm,

[0125] This kind of template contains Ni element and has ferromagnetic properties. In addition, the x value in the template can be adjusted to control the content of Ni element, thereby achieving the control of the magnetic strength of the template.

[0126] (1) Introduce elements such as iron, cobalt, and nickel at the B site, making the template have ferromagnetic properties;

[0127] (2) Introduce elements such as barium, strontium, lead, calcium, and magnesium at the A site to broaden the applicable range of this magnetic template;

[0128] (3) By regulating the types and contents of elements such as iron, cobalt, and nickel at the B site, the purpose of controlling the magnetic strength of the template can be achieved;

[0129] (4) By regulating the externally applied magnetic field, the direction of the template can be controlled.

[0130] (5)Among the A-site elements, the barium source is Ba(OH)2, BaCO3, Ba(NO3)2 or BaO; the strontium source is Sr(OH)2, SrCO3, Sr(NO3)2 or SrO; the magnesium source is Mg(OH)2, MgCO3, Mg(NO3)2 or MgO; the calcium source is Ca(OH)2, CaCO3, Ca(NO3)2 or CaO; the lead source is Pb(OH)2, PbCO3, Pb(NO3)2 or PbO;

[0131] (6)Among the B-site elements, the iron source is Fe(OH)3, Fe2(CO3)3, Fe(NO3)3, Fe2O3 or Fe3O4, the nickel source is Ni(OH)3, Ni2(CO3)3, Ni(NO3)3, Ni2O3; or Ni3O4, the cobalt source is Co(OH)3, Co2(CO3)3, Co(NO3)3, Co2O3 or Co3O4;

[0132] A preparation method of a flaky template with ferromagnetic properties, with the chemical formula AB 1-x B1 4x / 3 O3 or AB 1-x (B1B2) x O3, 0

Claims

1. A preparation method of a sheet template with ferromagnetic properties, characterized in that, The chemical formula of the flaky template is AB 1-x (B1B2) x O3, where 0 < x < 1, A is barium, strontium, lead, calcium or magnesium, B is titanium or zirconium, B1 is at least one of iron, cobalt and nickel elements, and B2 is at least one of niobium, tantalum and vanadium; Weigh the B-site element compound, bismuth source, B1-site element compound, and B2-site element compound according to the stoichiometric ratio, and weigh KCl or NaCl with a weight 0.5 - 10 times the total weight of the above raw materials for mixing to obtain mixture I. The mixture Ⅰ is kept at a high temperature of 800~1200 °C for 1~8 h to obtain a molten salt mixed product Ⅱ. The molten salt mixed product Ⅱ is washed with water to obtain a precursor. Then, the precursor is mixed with an A-site element compound and 1-fold weight of KCl or NaCl to obtain a mixture Ⅲ. The mixture Ⅲ is calcined at 800-1200 o °C for 1-8 h to obtain a molten salt mixed product Ⅳ. The molten salt mixed product Ⅳ is washed with water and pickled and soaked to obtain a flaky template containing B1 element.

2. The preparation method of the sheet template with ferromagnetic properties according to claim 1, characterized in that The A-site element compound is a barium source compound, strontium source compound, magnesium source compound, calcium source compound, or lead source compound. The barium source compound is Ba(OH)2, BaCO3, Ba(NO3)2, or BaO; the strontium source compound is Sr(OH)2, SrCO3, Sr(NO3)2, or SrO; the magnesium source compound is Mg(OH)2, MgCO3, Mg(NO3)2, or MgO; the calcium source compound is Ca(OH)2, CaCO3, Ca(NO3)2, or CaO; the lead source is Pb(OH)2, PbCO3, Pb(NO3)2, or PbO.

3. The preparation method of the sheet template with ferromagnetic properties according to claim 1, characterized in that, The compound of the B-site element is titanium dioxide or zirconium dioxide.

4. The preparation method of the sheet template with ferromagnetic properties according to claim 1, characterized in that, The B1-site element compound is an iron source compound, cobalt source compound, or nickel source compound; the iron source compound is Fe(OH)3, Fe2(CO3)3, Fe(NO3)3, Fe2O3, or Fe3O4, the nickel source compound is Ni(OH)3, Ni2(CO3)3, Ni(NO3)3, Ni2O3, or Ni3O4, and the cobalt source compound is Co(OH)3, Co2(CO3)3, Co(NO3)3, Co2O3, or Co3O4.

5. The preparation method of the sheet template with ferromagnetic properties according to claim 1, characterized in that, The B2-site element compound includes niobium pentoxide, tantalum pentoxide, or vanadium pentoxide.

6. The preparation method of the sheet template with ferromagnetic properties according to claim 1, characterized in that, The B-site element compound, bismuth source, B1-site element compound, B2-site element compound, and salt are mixed evenly by wet ball milling and dried, and after drying, they are sieved through a 40-mesh sieve.

7. A flaky template with ferromagnetic properties, characterized in that, Based on the preparation method described in any one of claims 1 to 6, the template length is between 3 and 25 microns, the thickness is 0.2 ± 2 microns, and the aspect ratio is greater than 8.

8. Use of the sheet-like template with ferromagnetic properties according to claim 7, characterized in that, When using the ferromagnetic sheet template for preparing the piezoelectric textured ceramic, the ferromagnetic sheet template is oriented by applying an external magnetic field.

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