A method for preparing Cr (23-x) Fe x C6 single crystal method and prepared crystal material

Abstract

The present invention belongs to the technical field of crystal preparation, and specifically relates to a method for preparing Cr (23‑x) Fe x The preparation method comprises the following steps: 1) preparing a mixed metal ingot of Cr, Fe and C, wherein the molar ratio of Cr, Fe and C is (23-x):x:1; 2) placing the mixed metal ingot obtained in step 1) into a four-arc single crystal pulling furnace; 3) evacuating the four-arc single crystal pulling furnace to 10 ‑4 After torr, it was protected by protective gas and then Cr was prepared by Czochralski method at a current of 13-15A. (23‑x) Fe x C6 single crystal. The present invention uses a four-arc single crystal pulling furnace to prepare high-purity Cr (23‑x) Fe x C6 single crystal, can obtain large pieces of high-quality single crystal samples.

Description

Technical Field

[0001] The present invention belongs to the technical field of crystal preparation, and specifically relates to a method for preparing Cr (23-x) Fe x Method for preparing C6 single crystal and the crystal material obtained. Background Art

[0002] Magnetic field, like chemical composition, temperature and pressure, is an important factor affecting phase transition. It is generally believed that carbides exhibit paramagnetism under high temperature and strong magnetic field, and the magnetic field has no effect on them. Experimental results show that stable alloy carbides will precipitate prematurely under the action of strong magnetic field. This result completely challenges the traditional view. For example, heat-resistant steel was tempered in a steady strong magnetic field of 12 Tesla, and the precipitation of alloy carbide M7C3 induced by strong magnetic field was observed and analyzed using transmission electron microscopy (Materials&Design 221(2022)111023). Carbide M 23 C6 has a giant magnetic moment because the magnetic moment of Fe atoms is 27% higher than that of pure iron. 23 C6 will have a strong response to the magnetic field, which will affect the creep performance of heat-resistant steel under high temperature and strong magnetic field. This response has two meanings: first, the 3d orbital electronic structure (including charge, spin and orbit) and lattice structure of Fe atoms in carbide and the rebalance of their interactions all produce microscopic responses to the external field; second, the carbide M 23 Response of C6 precipitation characteristics such as size, content, and distribution to strong magnetic fields.

[0003] Traditional single crystal growth methods include solid-phase reaction method, flux method, optical floating zone method, etc. Although the thermal sintering process can improve the quality of single crystals by adjusting the reactant ratio, the use of traditional processes to achieve gradient doping of samples has the disadvantages of low growth efficiency and complicated operation. It is also difficult to ensure the growth conditions of each gradient single crystal, and the process reproducibility is low. Summary of the Invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a method for preparing Cr (23-x) Fe x The present invention uses a four-arc single crystal pulling furnace to prepare high-purity Cr (23-x) Fe x C6 single crystal, can obtain large pieces of high-quality single crystal samples.

[0005] The technical solutions provided by the present invention are as follows:

[0006] A method for preparing Cr (23-x) Fe x C6 single crystal method, using four arc single crystal pulling furnace to prepare Cr (23-x)Fe x C6 single crystal, wherein x=0, 1, 2 or 3.

[0007] The present invention adopts a four-arc single crystal pulling furnace to produce large pieces of high-quality Cr (23-x) Fe x C6 single crystal sample.

[0008] Preparation of Cr (23-x) Fe x The method for C6 single crystal specifically comprises the following steps:

[0009] 1) preparing a mixed metal ingot of Cr, Fe and C, wherein the molar ratio of Cr, Fe and C is (23-x):x:1;

[0010] 2) placing the mixed metal ingot obtained in step 1) into a four-arc single crystal pulling furnace;

[0011] 3) Evacuate the four-arc single crystal pulling furnace to 10 -4 After torr, it was protected by protective gas, and then Cr was prepared by Czochralski method at a current of 13-15A. (23-x) Fe x C6 single crystal.

[0012] Based on the above technical solution, Cr, Fe and C can be used as raw materials to prepare Cr (23-x) Fe x C6 single crystal sample.

[0013] Preferably, the current in step 3) is 14A, or about 14A.

[0014] Specifically, the step 1) includes the following steps:

[0015] a) weighing Cr, Fe and C raw materials in a molar ratio of (23-x):x:1;

[0016] b) placing the raw material obtained in step a) into a vacuum arc melting furnace;

[0017] c) The vacuum arc melting furnace is evacuated and filled with protective gas, and then current is applied to melt the raw materials into ingots, and finally cooled to room temperature.

[0018] Specifically, in step a): weigh out elemental raw materials of Cr, Fe and C in a glove box filled with argon.

[0019] Based on the above technical solution, the risk of raw material oxidation can be avoided.

[0020] Specifically, in step b), the elemental raw material weighed in step a) is taken out by isolating it from the air with tin foil, and then placed in a vacuum arc melting furnace.

[0021] Based on the above technical solution, the risk of raw material oxidation can be avoided.

[0022] Specifically, in step c), the front and back sides are melted multiple times; and annealed by furnace cooling.

[0023] Based on the above technical solution, multiple melting on both sides of the ingot is performed in a vacuum arc melting furnace to ensure the uniformity of the ingot; after melting, an annealing treatment is required to reduce internal stress to prevent explosion during pulling.

[0024] Specifically, in step 3), the lifting needle has a rising rate of 3.5-4.5 mm / h, preferably 4 mm / h, or about 4 mm / h.

[0025] Based on the above technical solution, a crystalline material with large grains can be obtained.

[0026] The present invention also provides Cr prepared by the above method (23-x) Fe x C6 crystal material.

[0027] Prepared Cr (23-x) Fe x C6 can reach crystal rods 6-8cm long.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses high-purity iron powder, chromium powder, and carbon powder in different proportions as single-element raw materials, fully sintering them in a vacuum arc melting furnace, and repeatedly and fully fusing the front and back sides of the alloy ingot to form a uniform alloy ingot. The alloy ingot formed by multiple arc melting has uniform composition, low internal stress, and is not easy to break when stimulated by instantaneous local high temperature. Before melting in the vacuum arc melting furnace and the four-arc single crystal melting furnace, the method of using arc needles to heat the metal ingot is used to eliminate oxygen that may exist in the device, further reduce impurities that may appear in the growing single crystal, and improve the purity of the target product.

[0030] The single crystals of the components obtained by the present invention are of higher quality and larger overall volume, and compared with the flux method, the time for producing the single crystals is greatly reduced.

[0031] The Cr obtained by the present invention (23-x) Fe x C6 can be used as a material for magnetic research. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the XRD pattern of each embodiment.

[0033] Figure 2 These are optical photographs of various embodiments. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] Example 1

[0036] The single crystal Cr prepared in this embodiment 23 The C6 method is as follows:

[0037] In a glove box filled with argon protection, 8.4889 g of chromium particles and 0.5111 g of carbon blocks were weighed according to the molar ratio, wrapped tightly with tin foil, and after the gas inside was pressed out, they were moved out of the glove box and placed in a vacuum arc melting furnace.

[0038] Preparation of Cr 23 C6 alloy ingot

[0039] After wiping the inner wall of the vacuum arc melting furnace with alcohol, pour in the weighed powder element, adjust the position of the arc needle, and then evacuate the arc melting furnace, first using a mechanical pump and then a molecular pump, until the appropriate vacuum degree is reached (the reading is about 10 -3 (After pa, stop vacuuming and fill with argon until the pressure is slightly above 0, then turn on the power to start the arc. Use the arc needle to aim at the center of the titanium ingot and melt it for about 7 minutes to deoxidize it. Then move the arc needle to the sample to be melted and melt it. For the first melt, first circle the sample and melt it, then focus on heating and melting the center. Be careful not to bring the arc needle too close to the sample to prevent sample particles from being blown away. After uniform droplets are formed, turn the alloy ingot over and continue melting the second side. Each side should be fully and evenly heated. Finally, cool it to room temperature with the furnace and remove the single crystal ingot.

[0040] Preparation of Cr 23 C6 single crystal

[0041] Use alcohol to wipe the inner wall of the four-arc single crystal pulling furnace and the sample stage, grind the pulling needle to a suitable degree, install five tungsten needles (arc needles) and pulling needles used for melting; 23 Place the C6 alloy ingot on the sample stage of the four-arc single crystal pulling furnace, adjust the sample stage, arc needle and pulling needle to the appropriate position; vacuum to 10 -4torr, fill with argon until the pressure is slightly above 0, turn on the arc needle for melting the titanium ingot, and melt for about 7 minutes to deoxidize; then turn on the other four arc needles to heat and melt the four sides of the alloy ingot until the current is about 14A. At this time, the alloy ingot is in a liquid molten state. Slowly insert the pulling needle into the center of the alloy ingot, fine-tune the current to a stable state, set the pulling needle to move slowly upward, turn on the rotation of the sample stage and the pulling needle, and continuously adjust the angle of the arc needle during the pulling process so that the sample adheres to the solid single crystal on the pulling needle, and the entire alloy ingot is in a liquid molten state. The whole process needs to last for more than 5 hours until a crystal rod of about 6 cm is grown; break the crystal rod in a mortar to obtain a large piece of crystal. This crystal is as Figure 2 As shown in part (1).

[0042] Example 2

[0043] The single crystal Cr prepared in this embodiment 22 The method of FeC6 is as follows:

[0044] In a glove box filled with argon protection, 8.0312 g of chromium particles, 0.3930 g of iron particles, and 0.5049 g of carbon blocks were weighed according to the molar ratio, tightly wrapped with tin foil, and after the gas inside was pressed out, they were moved out of the glove box and placed in a vacuum arc melting furnace.

[0045] Preparation of Cr 22 FeC6 alloy ingot

[0046] After wiping the inner wall of the vacuum arc melting furnace with alcohol, pour in the weighed powder element, adjust the position of the arc needle, and then evacuate the arc melting furnace, first using a mechanical pump and then a molecular pump, until the appropriate vacuum degree is reached (the reading is about 10 -3 (After pa, stop vacuuming and fill with argon until the pressure is slightly above 0, then turn on the power to start the arc. Use the arc needle to aim at the center of the titanium ingot and melt it for about 7 minutes to deoxidize it. Then move the arc needle to the sample to be melted and melt it. For the first melt, first circle the sample and melt it, then focus on heating and melting the center. Be careful not to bring the arc needle too close to the sample to prevent sample particles from being blown away. After uniform droplets are formed, turn the alloy ingot over and continue melting the second side. Each side should be fully and evenly heated. Finally, cool it to room temperature with the furnace and remove the single crystal ingot.

[0047] Preparation of Cr 22 FeC6 single crystal

[0048] Use alcohol to wipe the inner wall of the four-arc single crystal pulling furnace and the sample stage, grind the pulling needle to a suitable degree, install five tungsten needles (arc needles) and pulling needles used for melting; 22Place the FeC6 alloy ingot on the sample stage of the four-arc single crystal pulling furnace, adjust the sample stage, arc needle and pulling needle to the appropriate position; vacuum to 10 -4 torr, fill with argon until the pressure is slightly above 0, turn on the arc needle for melting the metal ingot, and melt for 7 minutes to deoxidize; then turn on the other four arc needles to heat and melt the four sides of the alloy ingot until the current is about 14A. At this time, the alloy ingot is in a liquid molten state. Slowly insert the pulling needle into the center of the alloy ingot, fine-tune the current to a stable state, set the pulling needle to move slowly upward, turn on the rotation of the sample stage and the pulling needle, and continuously adjust the angle of the arc needle during the pulling process so that the sample adheres to the solid single crystal on the pulling needle, and the entire alloy ingot is in a liquid molten state. The whole process needs to last for more than 5 hours until a crystal rod of about 7 cm is grown; break the crystal rod in a mortar to obtain a large piece of crystal. This crystal is like Figure 2 As shown in part (2).

[0049] Example 3

[0050] The single crystal Cr prepared in this embodiment 21 The method of Fe2C6 is as follows:

[0051] In a glove box filled with argon protection, 7.5651 g of chromium particles, 0.7748 g of iron particles, and 0.4981 g of carbon blocks were weighed according to the molar ratio, wrapped tightly with tin foil, and after the gas inside was pressed out, they were moved out of the glove box and placed in a vacuum arc melting furnace.

[0052] Preparation of Cr 21 Fe2C6 alloy ingot

[0053] After wiping the inner wall of the vacuum arc melting furnace with alcohol, pour in the weighed powder element, adjust the position of the arc needle, and then evacuate the arc melting furnace, first using a mechanical pump and then a molecular pump, until the appropriate vacuum degree is reached (the reading is about 10 -3 (After pa, stop vacuuming and fill with argon until the pressure is slightly above 0, then turn on the power to start the arc. Use the arc needle to aim at the center of the titanium ingot and melt it for about 7 minutes to deoxidize it. Then move the arc needle to the sample to be melted and melt it. For the first melt, first circle the sample and melt it, then focus on heating and melting the center. Be careful not to bring the arc needle too close to the sample to prevent sample particles from being blown away. After uniform droplets are formed, turn the alloy ingot over and continue melting the second side. Each side should be fully and evenly heated. Finally, cool it to room temperature with the furnace and remove the single crystal ingot.

[0054] Preparation of Cr 21 Fe2C6 single crystal

[0055] Use alcohol to wipe the inner wall of the four-arc single crystal pulling furnace and the sample stage, grind the pulling needle to a suitable degree, install five tungsten needles (arc needles) and pulling needles used for melting; 21 Place the Fe2C6 alloy ingot on the sample stage of the four-arc single crystal pulling furnace, adjust the sample stage, arc needle and pulling needle to the appropriate position; vacuum to 10 -4 torr, fill with argon until the pressure is slightly above 0, turn on the arc needle for melting the titanium ingot, and melt for 7 minutes to deoxidize; then turn on the other four arc needles to heat and melt the four sides of the alloy ingot until the current is about 14A. At this time, the alloy ingot is in a liquid molten state. Slowly insert the pulling needle into the center of the alloy ingot, fine-tune the current to a stable state, set the pulling needle to move slowly upward, turn on the rotation of the sample stage and the pulling needle, and continuously adjust the angle of the arc needle during the pulling process so that the sample adheres to the solid single crystal on the pulling needle, and the entire alloy ingot is in a liquid molten state. The whole process needs to last for more than 5 hours until a crystal rod of about 6 cm is grown; break the crystal rod in a mortar to obtain a large piece of crystal. This crystal is as Figure 2 As shown in part (3).

[0056] Example 4

[0057] The single crystal Cr prepared in this embodiment 20 The method of Fe3C6 is as follows:

[0058] In a glove box filled with argon protection, 7.3531 g of chromium particles, 1.1866 g of iron particles, and 0.5085 g of carbon blocks were weighed according to the molar ratio, tightly wrapped with tin foil, and after the gas inside was pressed out, they were moved out of the glove box and placed in a vacuum arc melting furnace.

[0059] Preparation of Cr 20 Fe3C6 alloy ingot

[0060] After wiping the inner wall of the vacuum arc melting furnace with alcohol, pour in the weighed powder element, adjust the position of the arc needle, and then evacuate the arc melting furnace, first using a mechanical pump and then a molecular pump, until the appropriate vacuum degree is reached (the reading is about 10 -3 (After pa, stop vacuuming and fill with argon until the pressure is slightly above 0, then turn on the power to start the arc. Use the arc needle to aim at the center of the titanium ingot and melt it for 7 minutes to deoxidize it. Then move the arc needle to the sample to be melted and melt it. For the first melt, first circle the sample and melt it, then focus on heating and melting the center. Be careful not to bring the arc needle too close to the sample to prevent particles from being blown away. After uniform droplets are formed, turn the alloy ingot over and continue melting the second side. Each side should be fully and evenly heated. Finally, cool it to room temperature with the furnace and remove the single crystal ingot.

[0061] Preparation of Cr 20 Fe3C6 single crystal

[0062] Use alcohol to wipe the inner wall of the four-arc single crystal pulling furnace and the sample stage, grind the pulling needle to a suitable degree, install five tungsten needles (arc needles) and pulling needles used for melting; 20 Place the Fe3C6 alloy ingot on the sample stage of the four-arc single crystal pulling furnace, adjust the sample stage, arc needle and pulling needle to the appropriate position; vacuum to 10 -4 torr, fill with argon until the pressure is slightly above 0, turn on the arc needle for melting the titanium ingot, and melt for about 7 minutes to deoxidize; then turn on the other four arc needles to heat and melt the four sides of the alloy ingot until the current is about 14A. At this time, the alloy ingot is in a liquid molten state. Slowly insert the pulling needle into the center of the alloy ingot, fine-tune the current to a stable state, set the pulling needle to move slowly upward, turn on the rotation of the sample stage and the pulling needle, and continuously adjust the angle of the arc needle during the pulling process so that the sample adheres to the solid single crystal on the pulling needle, and the entire alloy ingot is in a liquid molten state. The whole process needs to last for more than 5 hours until a crystal rod of about 6 cm is grown; break the crystal rod in a mortar to obtain a large piece of crystal. This crystal is as Figure 2 As shown in part (4).

[0063] Test Case

[0064] like Figure 1 As shown in FIG, are XRD patterns of the crystalline materials of Examples 1 to 4. It can be seen from the figure that the spectra of the materials of each example have basically no impurity peaks and the purity is greater than 99%.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing Cr (23-x) Fe x The method for C6 single crystal is characterized by: The following steps are involved: 1) preparing a mixed metal ingot of Cr, Fe and C, wherein the molar ratio of Cr, Fe and C is (23-x):x:1; 2) placing the mixed metal ingot obtained in step 1) into a four-arc single crystal pulling furnace; 3) Evacuate the four-arc single crystal pulling furnace to 10 -4 After torr, it was protected by protective gas, and then Cr was prepared by Czochralski method at a current of 13-15A. (23-x) Fe x C6 single crystal, where x = 0, 1, 2 or 3, and the lifting rate of the pulling needle is 3.5-4.5 mm / h.

2. Preparation of Cr according to claim 1 (23-x) Fe x The method for C6 single crystal is characterized in that The step 1) includes the following steps: a) Weigh Cr, Fe and C raw materials in a molar ratio of (23-x):x:1; b) placing the raw materials obtained in step a) into a vacuum arc melting furnace; c) The vacuum arc melting furnace is evacuated and filled with protective gas, and then current is applied to melt the raw materials into ingots, and finally cooled to room temperature.

3. Preparation of Cr according to claim 2 (23-x) Fe x The method for C6 single crystal is characterized in that In step a), elemental raw materials of Cr, Fe and C were weighed in a glove box filled with argon.

4. Preparation of Cr according to claim 2 (23-x) Fe x The method for C6 single crystal is characterized in that In step b), the elemental raw materials weighed in step a) are taken out by isolating them from air with tin foil and placed in a vacuum arc melting furnace.

5. Preparation of Cr according to claim 2 (23-x) Fe x The method for C6 single crystal is characterized in that In step c), the front and back sides are melted multiple times; and annealing is performed by furnace cooling.

6. A Cr prepared by the method according to any one of claims 1 to 5 (23-x) Fe x C6 single crystal material.

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