CN2715885Y - Gradient strong magnetic field unidirectional solidification crystallization apparatus - Google Patents

Abstract

The utility model relates to a unidirectional solidification and crystallization device with a strong gradient magnetic field, which belongs to the technical field of crystal preparation in which crystal growth is controlled by a magnetic field. The utility model comprises a crucible or a model for containing molten materials, and a heating element, a thermal insulation layer, a heat insulating jacket, a superconducting coil are arranged on the side thereof, and the superconducting coil is placed in a Dewar tank, and the crucible or the model is under the A cooler that can be fed into the coolant is provided; a guide rail and a platform are provided on the pull-out device at the bottom of the device, and the pull-out device can make the cooler on the platform move forward along the guide rail, and drive the upper crucible or model to move synchronously. The superconducting coil is fed with direct current up to 1000A, the magnetic induction intensity B of the generated magnetic field is in the range of 1-40T, and the value of Bz (dBz/dz) is in the range of 200-3400T ² /m. The device of the utility model can prepare crystalline crystal materials with uniform composition and properties.

Description

Gradient strong magnetic field unidirectional solidification and crystallization device

technical field

The utility model relates to a unidirectional solidification and crystallization device with a strong gradient magnetic field, which belongs to the technical field of crystal preparation in which crystal growth is controlled by a magnetic field.

Background technique

In the past, there were some technical defects and deficiencies in the methods and devices for unidirectional solidification and growth of crystal materials under the action of a magnetic field. Therefore, it is easy to produce segregation of solute, that is, segregation, which will lead to a decrease in the performance and homogeneity of the crystal material. Therefore, in order to alleviate this segregation, people have used the method of growing crystals in a space microgravity environment or in a drop tube, but the cost of growing crystal materials in a space environment is expensive, and in addition, the time for growing crystals in a drop tube is too short to grow Practical materials, so it is necessary to find a new method to prepare perfect and uniform crystal materials.

Contents of the invention

The object of the present invention is to provide a device for unidirectional solidification and crystallization under the control of a strong gradient magnetic field.

The purpose of this utility model is achieved through the following technical solutions.

The gradient strong magnetic field unidirectional solidification and crystallization device of the utility model includes a superconducting magnet equipped with a superconducting coil, a heating element, a thermal insulation layer, a controllable pulling device, etc. The crucible or model of the material has a heating element on its side, an insulation layer on the outside of the heating element, and an insulating water jacket on the outer side close to the insulation layer. A superconducting coil is installed on the outermost side, and the superconducting coil is placed in the Dewar In the tank, a thermal insulation sealing cover is provided above the container crucible or model, and a heat insulation pad is provided at the lower part; in the crucible or model, there is a gap between the molten material in the upper part and the solidification crystal part that will be formed in the lower part during operation A solidified crystallization interface is formed between them; a cooler that can be fed into the coolant is provided under the crucible or the model; a guide rail and a platform are provided on the upper part of the pull-out device at the lower part of the device, and the pull-out device can make the cooler on the platform move along the guide rail. Move forward and drive the upper crucible or model to move synchronously.

The superconducting coil is fed with direct current up to 1000A, the magnetic induction intensity B of the generated magnetic field is in the range of 1-40T, and the value of Bz (dBz/dz) is in the range of 200-3400T ² /m.

The utility model is designed according to the following principles: any substance has magnetism, and a magnetizing force is generated in a strong gradient magnetic field, and its magnetizing force can be expressed as:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&chi;</span>}}{{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; (</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&dtri;</span><span\; class="notranslate">\; )</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; B</span>}}$

Wherein, F—magnetizing force, N/Kg; χ—mass magnetic susceptibility; μ ₀ =4π×10 ^-7 Wb/m·A; B—magnetic field intensity, T. The direction of the force depends on χ( B · ) B, which can counteract the gravity when it is opposite to the gravity, thereby inhibiting the occurrence of segregation. At the same time, the strong static magnetic field can also generate a reverse Lorentz force to the convection in the conductive liquid to suppress it. Now the strong gradient magnetic field can be economically obtained for a long time, so the growth of crystal materials and other materials can be carried out on the ground for a long time, and the cost is greatly reduced.

The superconducting solenoid coil is in a superconducting state at low temperature, and a strong magnetic field greater than 1 Tesla is generated after the current is passed through, and according to the magnetic properties of the crystal material, χ( B·) The direction and size of B make it offset with gravity; the solid/liquid interface of the crystal material to be grown is kept at χ( B·) Near the maximum B value, the crystallized part can be continuously pulled out to crystallize a uniform crystal material.

Advantages of the present invention:

The device of the utility model has the advantages of simple structure and convenient operation, can prevent segregation from reducing crystal uniformity and affect the performance of crystal materials, and can prepare perfect and uniform crystal materials. The device of the utility model can realize solidification and crystallization in a microgravity environment on the ground, control solute distribution in one-way solidification crystallization, and produce materials with uniform composition and properties.

Description of drawings

Fig. 1 is a schematic structural diagram of a unidirectional solidification and crystallization device under a strong magnetic field of the present invention.

Figure 2 is a graph showing the relationship between the solidified crystal interface and the magnetic field parameter Bz (dBz/dz)

Detailed ways

Now in conjunction with accompanying drawing and embodiment, the utility model device is further described in the following.

Embodiment 1: Referring to Fig. 1 and Fig. 2, the gradient strong magnetic field unidirectional solidification and crystallization device of the present utility model includes a superconducting magnet equipped with a superconducting coil, a heating element, an insulating layer, a controllable pulling device, etc., the present invention The center of the device is provided with a crucible or model 3 containing molten material 4, a heating element 2 is provided on its side, an insulation layer 8 is provided on the outside of the heating element 2, and an insulating water jacket 5 is provided on the outside close to the insulation layer 8 , a superconducting coil 7 is arranged on the outermost side, and the superconducting coil 7 is placed in the Dewar tank 6, and a heat-insulation sealing cover 1 is arranged above the container crucible or the model 3, and a heat-insulation backing plate 10 is arranged at the bottom; the crucible or the model 3, a solidification crystallization interface 15 is formed between the upper molten material 4 and the lower solidification crystallization part 9 that will be formed during the operation; the crucible or the mold 3 is provided with a cooler 11 that can pass through the coolant Guide rail 13 and platform 12 are provided above the pull-out device 14 at the bottom of the device, pull-out device 14 can make cooler 11 on the platform 12 move forward along guide rail 13, and drive the upper crucible or model 3 to move synchronously.

When the superconducting coil in the superconducting magnet is in the low-temperature superconducting state, direct current can be applied, up to 1000A, which can generate a strong magnetic field above 10T, and increase the value of Bz (dBz/dz) as much as possible, where Bz is the axis Magnetic induction intensity, dBz/dz is the magnetic field gradient (see Figure 2).

In the course of operation, first determine the solidification crystal interface position 15 according to the magnetic properties and solidification properties of the material, then melt the material 4 in the crucible or model 3 under the heating of the heating element 2 without a magnetic field and keep it warm for a sufficient time, and then send it to the superconducting coil 7. Feed in an electric current to generate a predetermined intensity magnetic field; secondly, feed a coolant into the cooler 16 for cooling or control the heating power of the heating element 2, so that the solidified crystallization interface 15 is at the previously determined position; after a certain period of time, then Start the pull-out device 14 to make the condenser 11 and the platform 12 move forward along the guide rail 13, thereby driving the crucible or the model 3 to move synchronously, and pull out the solidified part 9 at a predetermined speed (keep the position of the solidified crystallization interface 15 relative to the magnetic field unchanged ), until the melt is completely solidified and crystallized.

The superconducting coil is fed with a direct current of up to 1000A, and the magnetic induction B of the generated magnetic field is in the range of 1-40T, and the value of Bz (dBz/dz) is in the range of 200-3400T ² /m, which varies according to the material.

The materials used can be rare earth metals, metal copper, metal aluminum and alloy steel and so on.

Claims (2)

1. A gradient strong magnetic field unidirectional solidification and crystallization device, comprising superconducting magnets equipped with superconducting coils, heating elements, insulation layers, controllable pulling devices, etc., is characterized in that the center of the device is provided with a molten state The crucible or model (3) of the material (4) is provided with a heating element (2) on its side, an insulation layer (8) is arranged on the outside of the heating element (2), and a heat insulation layer is arranged on the outside close to the insulation layer (8) The water jacket (5) is provided with superconducting coils (7) on the outermost side, and the superconducting coils (7) are placed in the Dewar tank (6), and an insulating sealing cover (1) is provided above the container crucible or model (3). ), the lower part is provided with a thermal insulation backing plate (10); in the crucible or the model (3), the molten state material (4) at the upper part and the solidified crystalline part (9) at the lower part that will be formed during the operation process are formed A solidified crystal interface (15); the crucible or model (3) is provided with a cooler (11) that can feed into the coolant; the pull-out device (14) at the bottom of the device is provided with a guide rail (13) and a platform ( 12), the pull-out device (14) can make the cooler (11) on the platform (12) move forward along the guide rail (13), and drive the upper crucible or model (3) to move synchronously. 2. the gradient strong magnetic field unidirectional solidification crystallization device according to claim 1, is characterized in that, described superconducting coil feeds direct current and is up to 1000A, and the magnetic induction intensity B of the magnetic field that produces is in the scope of 1-40T, and Bz (dBz/dz) values are in the range of 200-3400T ² /m.

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