阅读说明：本技术 一种多物理场对晶体转化和生长定向调控的方法 (Method for directionally regulating and controlling crystal transformation and growth by multiple physical fields ) 是由 瞿广飞 吴丰辉 赵晨阳 任远川 李军燕 刘亮亮 王晨朋 于 2020-11-06 设计创作，主要内容包括：本发明公开了多物理场对晶体转化和生长定向调控的方法,该方法是将晶体基元置于在转晶介质溶液中,以1~5℃/min的升温速率升温至50℃,同时施加20~36V电场和100~600转/min搅拌,温度升到50℃后继续在50℃、搅拌、电场作用下处理10~30min后；在20~100转/min搅拌、0.6~15V电场作用下,将温度以0.05~1℃/min的升温速率上升至80~100℃；停止加热,在0.04~1mT磁场作用下,以1~5℃/min的降温速率降温至室温,最后取出结晶干燥即得晶体；该方法合成的晶体具有较高的完整性,晶体形状、结构和生长方向易于控制,该方法成本较低并且切实可行。(The invention discloses a method for directionally regulating and controlling crystal transformation and growth by multiple physical fields, which comprises the steps of placing crystal elements in a crystal transformation medium solution, heating to 50 ℃ at a heating rate of 1-5 ℃/min, applying a 20-36V electric field and stirring at 100-600 rpm, and continuously treating for 10-30 min at 50 ℃ under the action of the stirring and electric field after the temperature is raised to 50 ℃; under the action of stirring at 20-100 rpm and an electric field of 0.6-15V, raising the temperature to 80-100 ℃ at a temperature rise rate of 0.05-1 ℃/min; stopping heating, cooling to room temperature at a cooling rate of 1-5 ℃/min under the action of a 0.04-1 mT magnetic field, and finally taking out crystals and drying to obtain crystals; the crystal synthesized by the method has higher integrity, the shape, the structure and the growth direction of the crystal are easy to control, and the method has lower cost and is feasible.)

1. A method for directionally regulating and controlling crystal transformation and growth by multiple physical fields is characterized by comprising the following steps:

(1) putting the crystal element into a crystal transfer medium solution with the mass concentration of 1-5%, heating to 50 ℃ at the heating rate of 1-5 ℃/min, applying an electric field of 20-36V and stirring at 100-600 rpm, and continuously processing for 10-30 min at 50 ℃ under the action of the stirring and the electric field after the temperature is raised to 50 ℃;

(2) under the action of stirring at 20-100 rpm and an electric field of 0.6-15V, raising the temperature to 80-100 ℃ at a temperature rise rate of 0.05-1 ℃/min;

(3) stopping heating, cooling to room temperature at a cooling rate of 1-5 ℃/min under the action of a 0.04-1 mT magnetic field, wherein the direction and the size of the magnetic field can change the formation and the growth of crystal nuclei, and finally taking out crystals and drying to obtain the crystals.

2. The method for multi-physical-field oriented control of crystal transformation and growth according to claim 1, wherein: the crystal transformation medium is sodium dodecyl sulfate, potassium tartrate and CuCl₂、CaCl₂Sodium hexametaphosphate-silica mixture, ethylene glycol, H₂SO₄-NaCl-H₂O, disodium hydrogen phosphate dodecahydrate, calcium dihydrogen phosphate, sodium phosphate and/or sodium oleate.

3. The method for multi-physical-field oriented control of crystal transformation and growth according to claim 1, wherein: the crystal unit is a raw material of a crystal to be synthesized.

4. The method for multi-physical-field oriented control of crystal transformation and growth according to claim 2, characterized in that: the sodium hexametaphosphate-silicon dioxide mixture is prepared by mixing sodium hexametaphosphate and silicon dioxide according to the mass ratio of 1: 1-5, and H₂SO₄-NaCl-H₂And O is obtained by adding 1-5 mg of NaCl into 1-5% of dilute sulfuric acid.

5. The method for multi-physical-field oriented control of crystal transformation and growth according to claim 1, wherein: the drying temperature is 45-60 ℃.

Technical Field

The invention belongs to the technical field of crystal material research, and particularly relates to a method for directionally regulating and controlling crystal transformation and growth by multiple physical fields.

Background

At present, crystal materials are not widely applied in industry, but have wide application prospects in the aspects of sintering, catalysis, sensing and the like of magnetic materials, electronic materials, optical materials and high-strength and high-density materials on the basis of excellent performance. Such as 100nmAl manufactured in the united states₂O₃The ceramic has a high strength of 2.4 GNm-2 and is useful as a part such as a high efficiency gas turbine, an aircraft, an automobile, etc. The large surface area, high surface activity, sensitivity to the surrounding environment, etc. of crystalline materials make them the most promising materials in the sensor manufacturing industry. The crystal material has the characteristics of light absorption, light emission and optical nonlinearity, so that the crystal material has wide application prospect in the future daily life and high technical field. For example, the strong absorption capacity of the nano oxide crystal to ultraviolet light can improve daily lighting equipment, prolong the lighting life and reduce the damage to human body;

nano SiO₂The low loss of the crystal material in the light transmission can greatly improve the light transmission efficiency; the excellent optical performance of the nano material enables the nano material to have application prospects in the aspects of optical storage and the like. The electric and magnetic properties of the crystal material are also widely applied in industry, for example, the giant magnetoresistance crystal material can be used as the next generation information storage read-write head material; soft magnetic crystalline materials are useful as high frequency transducers, magnetic heads. The use of nanocrystalline materials as magnetic recording materials can improve signal-to-noise ratios and improve image quality. Size-general ratio of nanocrystalline materialsThe cells and red blood cells in organisms are much smaller, which provides a research approach for biology, namely, cell separation and cell staining are carried out by using nano crystal materials, and special medicines or novel antibodies are prepared by using nano materials for local directional treatment and the like. Nanocrystalline materials thus have important applications in biology and medicine. The crystal material has unique physical characteristics, and can realize the interaction and conversion of different energy forms such as electricity, light, sound, heat, magnetism, force and the like, thereby being a basic material of photoelectric technology, laser technology and microelectronic technology. So far, most of the functional crystal materials belong to inorganic non-metallic materials, which are characterized by multiple functions and stable performance, and the application of the materials is spread in various fields of industry, agriculture, medicine, military affairs and scientific technology.

The existing crystal growth and control methods mainly comprise a melt method, a solution method and a vapor phase method, and the methods have the advantages of high cost, difficulty in control, low growth speed, long period, high requirement on condition stability, weak basic research on crystal growth and crystal materials, and lack of long-term and basic research work. Crystal growth and transformation control techniques fall behind. At present, the crystal growth in China depends on the skills of operators, but the advantage cannot be maintained for a long time, and compared with the situation that a microcomputer is generally adopted abroad to accurately control the growth process, the method has obvious difference, so that the invention is imperative to invent the method capable of accurately regulating and controlling the crystal transformation and growth.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for directionally regulating and controlling the crystal transformation and growth by multiple physical fields, which ensures that the synthesized crystal has higher integrity in structure and composition, the shape, structure and growth direction of the crystal are easy to control, the controllability is stronger in the growth and transformation processes of the crystal, the synthesized crystal can meet higher practical value and specific use requirements, and the method has lower cost and is practical and feasible.

The method for directionally regulating and controlling the crystal transformation and growth by multiple physical fields comprises the steps of dissolving crystal elements in a crystal transformation medium solution with the mass concentration of 1-5%, heating to 50 ℃ at the heating rate of 1-5 ℃/min, applying an electric field of 20-36V and stirring at 100-600 rpm, heating to 50 ℃, continuing to process for 10-30 min at 50 ℃ under the action of the stirring and the electric field; under the action of stirring at 20-100 rpm and an electric field of 0.6-15V, raising the temperature to 80-100 ℃ at a temperature rise rate of 0.05-1 ℃/min; stopping heating, cooling to room temperature at a cooling rate of 1-5 ℃/min under the action of a 0.04-1 mT magnetic field, wherein the direction and the size of the magnetic field can change the formation and the growth of crystal nuclei, and finally taking out crystals and drying to obtain the crystals.

The crystal transformation medium is sodium dodecyl sulfate, potassium tartrate and CuCl₂、CaCl₂Sodium hexametaphosphate-silicon dioxide mixture (mass ratio is 1: 1-5), ethylene glycol and H₂SO₄-NaCl-H₂O (1-5 mg of NaCl is added into 1-5% of dilute sulfuric acid), one or more of disodium hydrogen phosphate dodecahydrate, calcium dihydrogen phosphate, sodium phosphate and sodium oleate, and the main function of the crystal is to selectively adsorb on a certain crystal face of the crystal or change the specific surface free energy of the crystal face; the growth of the crystal face is hindered, and the growth and development of other crystal face directions are normal; the different adsorption of different crystal transformation agents on each crystal face of the crystal can cause obvious difference between the crystal form and the crystal size.

The crystal unit is a raw material for synthesizing crystals, is the most basic structural unit for synthesizing the crystals, and can be molecules, atoms, ions or (atomic) molecular aggregates with certain geometrical configurations.

The multi-physical field conditions in the method are an electric field, a magnetic field, a temperature field and a flow velocity field; wherein the electric field voltage is 0.6-36V, and the electrode material is stainless steel, graphite or carbon; the magnetic field is generated by a Helmholtz coil in the pulsed magnetic field generator, the voltage applied to the coil is 0.6-360V, the number of turns of the Helmholtz coil is 50-1000, and the magnetic field intensity is 0.04-1 mT; the temperature field is in the range of room temperature to 100 ℃; the flow velocity of the flow velocity field is 20-600 r/min.

The drying temperature is 45-60 ℃.

The regulation mechanism of crystal transformation and growth by multiple physical fields is as follows:

the transformation and growth of the crystal mainly relate to momentum, mass and heat transport, and the essence is to change the relationship among the internal structure, defects, growth conditions and crystal form of the crystal, wherein, the multi-physical field is the external condition of the crystal growth and plays the role of momentum, mass and heat transport, and the solution of the crystal transformation medium selectively adsorbs or changes the specific surface free energy of a crystal face on a certain crystal face of the crystal; the growth of the crystal face is hindered, and the growth and development of other crystal face directions are normal; the different adsorption effects of different crystal transformation agents on each crystal face of the crystal can cause obvious difference between the crystal form and the crystal size; under the action of an ultrasonic field and a moderate temperature field, dissolving a medium solution to ensure that a crystal transfer agent in the solution is uniformly distributed in the solution, gradually dissolving the prepared elementary crystal material under the condition of a plurality of physical fields, and gradually increasing the temperature to a high temperature state; under the action of the electric field, the crystal elements respectively move towards the cathode and the anode of the electric field due to different electrical properties, so that the intensity of the electric field can be controlled to adjust the motion condition of the charged elements; under the action of a magnetic field, because the diamagnetism, paramagnetism, ferromagnetism and the like of the crystal elements are directionally distributed or fixed under the condition of the magnetic field, the combined action of the electric field and the magnetic field can enhance the degree of order in the crystal forming process, change the strength of the electric field and the magnetic field and further change the structure and the form of the crystal; under the action of the optical field, the crystal growth direction can be induced; while the pressure effect changes the crystal shape and the temperature field provides primarily the momentum and heat for crystal transformation and growth.

In the process of crystal growth, continuous growth is carried out on the rough interface of the crystal surface, the rough interface is a growth position everywhere, and the atoms in the solution almost continuously enter the crystallization position on the interface, so the growth of the rough interface is called as 'continuous growth'. After stable crystal nucleus is formed, under the condition of certain temperature and supersaturation degree, the crystal grows according to a certain speed. Crystal growth resembles a diffusion process, which depends on the ability of molecules or atoms to diffuse away from the melt (liquid phase) towards the interface. The free energy of one atom or molecule on the liquid side of the interface is Gl, the free energy of one atom or molecule on the crystal side is Gc, and the change of the free energy when one atom is transferred to the solid phase is as follows: Gl-Gc = V Δ GV; here, V is the volume of the formed crystal nuclei; the activation energy when an atom or molecule moves from a liquid to a crystal through an interface is Δ Ga, and multiple physical fields simultaneously affect the activation energy.

The method has the advantages and the technical effects that:

(1) the synthesized crystal has higher integrity in structure and composition;

(2) a new crystal growth control method is proposed;

(3) the shape, the structure and the growth direction of the crystal are easy to control, and the controllability is strong in the crystal conversion and growth processes;

(4) the synthesized crystal can meet higher practical value and specific use requirements;

(5) the cost is low, the growth speed is high, the period is short, and the method is easy to control;

(6) the method is low in cost and feasible.

Drawings

FIG. 1 is a schematic enlarged view of the crystal obtained in example 1;

FIG. 2 is a schematic diagram of the structure of the crystal obtained in example 2 after enlargement;

FIG. 3 is a schematic diagram of the structure of the crystal obtained in example 3.

Detailed Description

The technical solution of the present invention is further described below with reference to specific examples, but the scope of the present invention is not limited to the description.

Example 1: the method for directionally regulating and controlling the transformation and growth of the gypsum crystal by multiple physical fields comprises the following steps:

(1) preparing a crystal transformation medium solution, and preparing a sodium dodecyl sulfate solution with the mass concentration of 1%;

(2) putting gypsum into 1% sodium dodecyl sulfate solution, increasing the temperature to 50 deg.C at a rate of 1 deg.C/min, simultaneously applying 20V electric field and stirring at 100 rpm, and after the temperature is increased to 50 deg.C, continuously treating at 50 deg.C under the action of stirring and electric field for 10 min; wherein the anode used for applying the electric field is a stainless steel electrode, and the cathode is a graphite electrode;

(3) under the stirring of 20 revolutions per minute and the action of a 0.6V electric field, the temperature of 50 ℃ is increased by 85 ℃ at the heating rate of 0.05 ℃/min;

(4) stopping heating after the temperature reaches 85 ℃, applying a magnetic field of 0.04mT (generated by a Helmholtz coil, the number of turns of the Helmholtz coil is 500 turns), cooling to room temperature at the speed of 5 ℃/min with the direction of the magnetic field being horizontal, and finally taking out crystals to be dried at 60 ℃ to obtain crystals; the formed crystal structure is shown in figure 1, the gypsum crystal has various crystal structures in shape, alpha gypsum crystal with large length-diameter ratio of hexagonal prism crystal form is formed, and the length-diameter ratio is 150-180; the flaky beta gypsum crystal has smooth crystal surface, so that the crystal grows horizontally due to the horizontal placement of the magnetic field, and has high purity and regular shape.

Example 2: multiple physical field pair SiO₂The method for crystal transformation and growth directional control comprises the following steps:

(1) preparing a crystal transition medium solution, and preparing a sodium hexametaphosphate-silicon dioxide mixture solution with the mass concentration of 5% (the mass ratio of the sodium hexametaphosphate to the silicon dioxide is 1: 1);

(2) putting amorphous silicon dioxide powder into a sodium hexametaphosphate-silicon dioxide mixture solution, firstly increasing the temperature to 50 ℃ at the rate of 5 ℃/min, simultaneously applying a 36V electric field and stirring at 600 revolutions per minute, and continuously treating for 30min at 50 ℃ under the action of the stirring and the electric field after the temperature is increased to 50 ℃; wherein the positive electrode and the negative electrode used for applying the electric field are both graphite electrodes;

(3) under the stirring of 100 r/min and the action of a 15V electric field, the temperature of 50 ℃ is increased by 100 ℃ at the heating rate of 1 ℃/min;

(4) stopping heating after the temperature reaches 100 ℃, applying a magnetic field of 1mT (generated by a Helmholtz coil, the number of turns of the Helmholtz coil is 1000 turns), wherein the direction of the magnetic field is horizontal and vertical, cooling to room temperature at the speed of 1 ℃/min, and finally taking out crystals to be dried at 45 ℃ to obtain crystals; the resulting crystal structure is shown in FIG. 2, SiO₂The crystal structure is relatively complete, the crystal form is relatively regular under the control of multiple physical fields, the crystal is mostly of an octahedral structure, the texture is relatively good, and the whole process time for forming the crystal is shortShorter.

Example 3: this multi-physical field is to Al₂O₃The method for crystal transformation and growth directional control comprises the following steps:

(1) preparing a crystal transformation medium solution, and preparing a monocalcium phosphate solution with the mass concentration of 2.5%;

(2) mixing Al₂O₃Putting the powder into calcium dihydrogen phosphate solution, increasing the temperature to 50 deg.C at a rate of 2.5 deg.C/min, simultaneously applying 25V electric field and stirring at 400 rpm, heating to 50 deg.C, and continuously treating at 50 deg.C under the action of stirring and electric field for 20 min; wherein the anode electrode and the anode electrode used for applying the electric field are both stainless steel electrodes;

(3) under the stirring of 50 revolutions per minute and the action of a 10V electric field, the temperature of 50 ℃ is raised by 95 ℃ at the heating rate of 0.5 ℃/min;

(4) stopping heating after the temperature reaches 95 ℃, applying a magnetic field of 0.5mT (generated by a Helmholtz coil, the number of turns of the Helmholtz coil is 500 turns), cooling to room temperature at the speed of 2.5 ℃/min with the direction of the magnetic field being horizontal and vertical, and finally taking out crystals to be dried at 50 ℃ to obtain the crystals; the crystal structure formed is as shown in FIG. 3, Al formed under the control of multiple physical fields₂O₃The crystal shape is regular, the crystal size is uniform, and the texture is good.