A method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction

Abstract

The invention discloses a method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction, the method comprising: preparing AlCl3&KCl eutectic salt from anhydrous AlCl3 powder and KCl powder, then mixing a reducing agent and TiO2, and preparing TiAl alloy powder by magnesium thermal reduction reaction at high temperature. The invention prepares TiAl alloy by magnesium thermal reduction assisted by AlCl3&KCl molten salt, uses AlCl3&KCl molten salt as a reaction medium, improves the mass transfer efficiency of TiO2 in the low-temperature reduction process, completes the reduction of TiO2 and the combination of TiAl alloy, realizes the process of preparing TiAl alloy by reducing TiO2 in one step, provides a method for preparing TiAl master alloy powder with low energy consumption, short process and mature technology, and solves the problem of complex and high energy consumption of existing TiAl alloy powder preparation process.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to a method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction. Background Art

[0002] Titanium aluminum alloys are widely used in aerospace, submarine engineering and biomedical fields due to their excellent properties such as high specific strength, low density, corrosion resistance and good biocompatibility. However, due to the high price of titanium metal, the use of titanium and titanium alloys has been limited to high-end military and aerospace manufacturing, and has not been expanded in the civilian field. So far, the mainstream method of producing titanium metal is still based on the Kroll method, which is the process of preparing sponge titanium by high-temperature chlorination of titanium ore and then magnesium thermal reduction. The Kroll method is an energy-intensive industry, and the process of producing sponge titanium is long, polluting and energy-intensive. Therefore, the titanium industry needs to develop new preparation technologies to reduce energy consumption and reduce the price of titanium alloys.

[0003] At present, the preparation of titanium aluminum alloy powder is mainly carried out by single metal smelting, which requires a lot of raw materials and consumes a lot of energy. Moreover, the TiAl alloy after high-temperature smelting is a solid metal ingot, which needs to be granulated and balled at high temperature to form TiAl alloy powder. With the gradual development of 3D printing, the demand for titanium alloy powder will gradually increase in the future. Therefore, the present invention proposes to prepare titanium aluminum alloy powder in a short process by molten salt-assisted method to reduce energy loss and increase industrial efficiency. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction in view of the deficiencies of the above-mentioned prior art. The method prepares TiAl alloy by eutectic melting of anhydrous AlCl3 powder and KCl powder to obtain AlCl3&KCl eutectic salt, and then prepares TiAl alloy by assisted magnesium thermal reduction of AlCl3&KCl molten salt, thereby improving the mass transfer efficiency of TiO2 in the low-temperature reduction process, completing the reduction of TiO2 and the combination of TiAl alloy in the low-temperature reduction reaction, realizing the one-step process of preparing TiAl alloy from TiO2 reduction, providing a method for preparing TiAl intermediate alloy powder with low energy consumption, short process and mature technology, and solving the problem of complex and high energy consumption of existing TiAl alloy powder preparation process.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction, characterized in that the method comprises the following steps:

[0006] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder and Mg particles as raw material powders;

[0007] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed in a mass ratio of 0.5-0.85:1 of the mass of the anhydrous AlCl3 powder to the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0008] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at a temperature of 300°C to 600°C for 72 hours under an argon atmosphere, and then the temperature is raised to 700°C to 800°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0009] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 700°C~900°C under the condition of passing argon gas for 30min~180min to obtain a mixture of slag and metal;

[0010] Step 5, pickling: the mixture of slag and metal obtained in step 4 is put into a hydrochloric acid solution for pickling, and then filtered to obtain metal powder;

[0011] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling and flotation to obtain TiAl alloy powder.

[0012] The present invention comprises the following steps: mixing anhydrous AlCl3 powder and KCl powder, heating the mixture under an argon atmosphere, then heating the mixture and introducing HCl gas to remove moisture and oxygen impurities, so that the two salts undergo a eutectic reaction to obtain an AlCl3&KCl eutectic salt, thereby reducing the volatilization of AlCl3 in a later reaction; mixing the AlCl3&KCl eutectic salt with TiO2 powder and Mg particles, and heating the mixture under an argon atmosphere, namely, preparing a TiAl alloy by assisted magnesium thermal reduction through an AlCl3&KCl molten salt; a reduction reaction at a low temperature completes the reduction of TiO2 and the combination of the TiAl alloy, thereby realizing a one-step process of preparing a TiAl alloy through reduction of TiO2; finally, pickling in a hydrochloric acid solution and ball milling and flotation are performed to remove excess Al2O3 powder and other impurities, and purifying the mixture to obtain a TiAl alloy powder; strictly controlling the preparation process to ensure that the impurity content of the TiAl master alloy powder is controlled at an extremely low level; and the prepared TiAl master alloy powder has uniform composition and high yield, thereby providing a reliable raw material supply for the preparation of downstream material Ti-based high-temperature alloys or 3D-printed products.

[0013] In the preparation of TiAl alloy by AlCl3&KCl molten salt assisted magnesium thermal reduction in the present invention, Mg will react with AlCl3 first, and then the generated Al will be immediately added to the process of reducing TiO2. The whole process is actually that magnesium and aluminum act as reducing agents to reduce TiO2. At low temperatures, the alloy reaction of Al and Ti is mainly a liquid-solid reaction. TiAl alloy can also be formed by solid phase diffusion at low temperatures. In addition, magnesium reduction of AlCl3 will also release a large amount of heat, which also has a certain driving effect on the formation of TiAl alloy.

[0014] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the mass purity of the anhydrous AlCl3 powder, KCl powder, TiO2 powder and Mg particles in step 1 is greater than 99.5%, the particle size of the TiO2 powder is 200 mesh to 300 mesh, and the particle size of the Mg particles is 2mm to 3mm. The present invention effectively reduces the impurity content of the TiAl master alloy powder by strictly controlling the purity of the raw materials AlCl3, KCl, TiO2 and Mg particles, ensures the purity of the final product TiAl master alloy, and controls the particle size of the reducing agent to achieve safe and effective maximum reduction rate for reduction, thereby improving the yield of the TiAl alloy powder.

[0015] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the mass ratio of the mass of the anhydrous AlCl3 powder described in step 2 to the total mass of the anhydrous AlCl3 powder and the KCl powder is 0.65 to 0.7. The present invention calculates the eutectic region of the reaction medium AlCl3 & KCl by thermodynamic software Factsage, thereby obtaining the mass ratio of the mass of the anhydrous AlCl3 powder to the total mass of the anhydrous AlCl3 powder and the KCl powder, ensuring that a large amount of volatilization of the eutectic salt is avoided during the metal thermal reduction process, and ensuring the effectiveness of the AlCl3 & KCl medium during the reaction process.

[0016] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the heating temperature under the argon atmosphere in step 3 is 300° C. to 400° C. The present invention effectively reduces the volatilization of AlCl3 by controlling the heating temperature.

[0017] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the heating temperature in step 4 is 750°C to 800°C. The present invention ensures the reduction reaction at low temperature through the heating temperature, completes the reduction of TiO2 and the combination of TiAl alloy, and realizes the process of preparing TiAl alloy from TiO2 reduction in one step. As the reaction temperature increases and the reaction time prolongs, the oxygen content of the product will gradually increase. The route of the entire reaction process is clarified through thermodynamic calculations and experiments, and a TiAl3 alloy powder with an oxygen content of 3.91wt% is obtained by reacting at 750°C for 2h, and the particle size of the alloy powder is concentrated in the range of 450μm.

[0018] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the mass fraction of the hydrochloric acid solution in step 5 is 3% to 5%, and the pickling time is 1h to 2h. The present invention removes the molten salt and unreacted metallic magnesium in the slag by acid leaching the reaction product, and the recovered MgCl2 and KCl can be dried, purified and reused, and the impurities are fully removed by controlling the mass fraction of the hydrochloric acid solution and the pickling time.

[0019] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the mass ratio of the ball, material and water in the ball milling flotation described in step 6 is 2:1:5. The present invention removes impurities in the alloy by ball milling flotation, controls the enrichment of impurity elements such as oxygen and nitrogen in the powder during the ball milling process, and at the same time, argon gas is introduced into the ball milling tank during the ball milling process to ensure the minimum final impurity content, avoid oxidation of the TiAl alloy powder, and ensure the quality of the TiAl master alloy. In addition, the present invention performs pickling and rinsing surface decontamination treatment after ball milling to avoid the influence of surface stains on the finished product during the ball milling process.

[0020] The above-mentioned method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction is characterized in that the TiAl alloy powder in step 6 is composed of the following elements in mass percentage: Ti 40% to 70%, and the balance is Al and inevitable impurities. The present invention ensures the high temperature performance of the TiAl alloy powder by controlling the component content of the TiAl alloy powder, wherein the appropriate titanium content can provide the necessary strength of the alloy in a high temperature environment without sacrificing too much the lightweight characteristics of the material, and Al easily forms a dense aluminum oxide layer at high temperature, which can protect the substrate from oxidation corrosion, and helps to improve the corrosion resistance and oxidation resistance of the alloy.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention prepares TiAl alloy by eutecticizing anhydrous AlCl3 powder and KCl powder to obtain AlCl3&KCl eutectic salt, and then preparing TiAl alloy by AlCl3&KCl molten salt-assisted magnesium thermal reduction, thereby improving the mass transfer efficiency of TiO2 in the low-temperature reduction process. The reduction reaction at low temperature completes the reduction of TiO2 and the combination of TiAl alloy, realizing the one-step process of preparing TiAl alloy from TiO2 reduction, providing a preparation method of TiAl master alloy powder with low energy consumption, short process and mature technology, and solving the problem of complex and high energy consumption of existing TiAl alloy powder preparation process.

[0023] 2. The TiAl master alloy powder of the present invention has uniform element distribution, no segregation and high melting point phase, and very low impurity content. It has the characteristics of high purity, good powder dispersibility, uniform composition and organization. Compared with the traditional process of adding metal aluminum and sponge titanium to smelt and prepare TiAl alloy powder, the smelting temperature required is lower, the cost is less, and the energy consumption is effectively reduced, providing a more reasonable solution for the development of TiAl alloy powder.

[0024] 3. The preparation method of the present invention uses TiO2 and Mg powder, AlCl3 as raw materials, which can be mixed in proportion according to the requirements of the TiAl master alloy grade. At the same time, TiAl alloy powders with different Ti contents can be obtained by controlling the reaction time, thereby ensuring that the composition of the TiAl master alloy powder is controllable. The TiAl alloy powder preparation process is carried out under an argon atmosphere, and the contents of impurity elements such as carbon, oxygen, and nitrogen during the powder reaction process are strictly controlled to achieve pollution-free preparation. The prepared TiAl alloy powder has high purity, uniform element distribution, no segregation, and no metallurgical defects.

[0025] 4. The present invention ensures that the impurity content of the TiAl master alloy powder is controlled at an extremely low level by strictly controlling the preparation process and parameters, and the prepared TiAl master alloy powder has uniform composition and high yield, providing a reliable raw material supply for the preparation of downstream materials Ti-based high-temperature alloys or 3D printed products. Compared with the process of preparing TiAl alloys by the traditional element method, the one-step method of the present invention prepares TiAl alloy powder with controllable composition, low impurity content, uniform composition, and is not easy to segregate. Compared with the preparation of TiAl alloys by mechanical alloying, the present invention requires lower temperature, less energy consumption, and low cost.

[0026] 5. The present invention combines a high-temperature thermal reduction process with a pickling process to achieve environmentally friendly and economical preparation of TiAl alloy powder.

[0027] 6. The method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction of the present invention is simple and effective, and is suitable for large-scale industrial production.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a process flow chart for preparing TiAl alloy powder by molten salt assisted metal thermal reduction.

[0030] Figure 2 is the XRD pattern of the TiAl alloy powder prepared in Example 1 of the present invention.

[0031] Figure 3 is a SEM image of the TiAl alloy powder prepared in Example 1 of the present invention.

[0032] Figure 4 This is an EDS graph of Ti in the TiAl alloy powder prepared in Example 1 of the present invention.

[0033] Figure 5 This is an EDS graph of Al in the TiAl alloy powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] Figure 1 The process flow chart of the present invention for preparing TiAl alloy powder by molten salt assisted metal thermal reduction is as follows: Figure 1 It can be seen that the present invention obtains TiAl alloy powder through raw material selection, molten salt mixing, salt making, heating reaction, acid washing and flotation.

[0035] Example 1

[0036] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti 40% and the balance of Al and inevitable impurities.

[0037] This embodiment includes the following steps:

[0038] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0039] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed at a mass ratio of 0.65:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0040] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at 300°C for 72h under argon atmosphere, then the temperature is raised to 700°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0041] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 700°C and heating for 120 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0042] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 4% by mass hydrochloric acid solution for pickling for 1.5 hours, and then filtered to obtain metal powder;

[0043] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0044] The TiAl alloy powder prepared in this example was tested for composition, and the results are shown in Table 1.

[0045] Table 1

[0046]

[0047] It can be seen from Table 1 that the content of impurity elements in the TiAl alloy powder prepared in this embodiment is relatively low, which means that the TiAl alloy powder prepared in the present invention avoids pollution of the external environment.

[0048] Figure 2 is the XRD pattern of the TiAl alloy powder prepared in this embodiment. Figure 2 It can be seen that the TiAl alloy powder prepared in this embodiment is mainly TiAl3, and has a small amount of TiAl2, indicating that the product is mainly TiAl alloy.

[0049] Figure 3 is a SEM image of the TiAl alloy powder prepared in this embodiment. Figure 2 It can be seen that the TiAl alloy powder prepared in this embodiment is metal particles, and the product is distributed in the form of chips.

[0050] Figure 4 is the EDS image of Ti in the TiAl alloy powder prepared in this embodiment, Figure 5 is the EDS graph of Al in the TiAl alloy powder prepared in this embodiment. Figure 4 and Figure 5 It can be seen from the figure that titanium and aluminum are evenly distributed in the TiAl alloy powder prepared in this embodiment.

[0051] Example 2

[0052] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti 50% and the balance of Al and inevitable impurities.

[0053] This embodiment includes the following steps:

[0054] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0055] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed at a mass ratio of 0.68:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0056] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at 450°C for 72h under argon atmosphere, then the temperature is raised to 750°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0057] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 800°C and heating for 120 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0058] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 3% by mass hydrochloric acid solution for pickling for 2 hours, and then filtered to obtain metal powder;

[0059] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0060] The TiAl alloy powder prepared in this example was tested for composition, and the results are shown in Table 2.

[0061] Table 2

[0062]

[0063] It can be seen from Table 2 that the content of impurity elements in the TiAl alloy powder prepared in this embodiment is relatively low, which means that the TiAl alloy powder prepared in the present invention avoids pollution of the external environment.

[0064] Example 3

[0065] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti of 60% and the balance of Al and inevitable impurities.

[0066] This embodiment includes the following steps:

[0067] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0068] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed in a mass ratio of 0.7:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0069] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at 600°C for 72h under an argon atmosphere, then the temperature is raised to 750°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0070] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 850°C and heating for 120 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0071] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 5% by mass hydrochloric acid solution for pickling for 1 hour, and then filtered to obtain metal powder;

[0072] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0073] The TiAl alloy powder prepared in this example was tested for composition, and the results are shown in Table 3.

[0074] Table 3

[0075]

[0076] It can be seen from Table 3 that the content of impurity elements in the TiAl alloy powder prepared in this embodiment is relatively low, which means that the TiAl alloy powder prepared in the present invention avoids pollution of the external environment.

[0077] Example 4

[0078] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti of 70% and the balance of Al and inevitable impurities.

[0079] This embodiment includes the following steps:

[0080] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0081] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed at a mass ratio of 0.65:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0082] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at 500°C for 72h under an argon atmosphere, then the temperature is raised to 700°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0083] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 900°C and heating for 120 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0084] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 3% by mass hydrochloric acid solution for pickling for 2 hours, and then filtered to obtain metal powder;

[0085] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0086] The TiAl alloy powder prepared in this example was tested for composition, and the results are shown in Table 4.

[0087] Table 4

[0088]

[0089] It can be seen from Table 4 that the content of impurity elements in the TiAl alloy powder prepared in this embodiment is relatively low, which means that the TiAl alloy powder prepared in the present invention avoids pollution of the external environment.

[0090] Example 5

[0091] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti of 65% and the balance of Al and inevitable impurities.

[0092] This embodiment includes the following steps:

[0093] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0094] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed at a mass ratio of 0.50:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0095] Step 3, salt preparation: the AlCl3 and KCl mixed powder obtained in step 2 is heated at 350°C for 72h under argon atmosphere, then the temperature is raised to 700°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0096] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 750°C and heating for 180 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0097] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 3% by mass hydrochloric acid solution for pickling for 2 hours, and then filtered to obtain metal powder;

[0098] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0099] Example 6

[0100] This embodiment is to prepare TiAl alloy powder with a mass percentage of Ti 55% and the balance of Al and inevitable impurities.

[0101] This embodiment includes the following steps:

[0102] Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder with a particle size of 200-300 mesh, and Mg particles with a particle size of 2mm-3mm with a mass purity greater than 99.5% as raw material powders;

[0103] Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed at a mass ratio of 0.85:1 between the mass of the anhydrous AlCl3 powder and the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl;

[0104] Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at 400°C for 72h under an argon atmosphere, then the temperature is raised to 800°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt;

[0105] Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 780°C and heating for 30 minutes under the condition of passing argon gas to obtain a mixture of slag and metal;

[0106] Step 5, pickling: the mixture of slag and metal obtained in step 4 is placed in a 3% by mass hydrochloric acid solution for pickling for 2 hours, and then filtered to obtain metal powder;

[0107] Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling flotation at a mass ratio of balls, material, and water of 2:1:5 to obtain TiAl alloy powder.

[0108] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction, characterized in that: The method comprises the following steps: Step 1, raw material selection: select anhydrous AlCl3 powder, KCl powder, TiO2 powder and Mg particles as raw material powders; Step 2, molten salt mixing: the anhydrous AlCl3 powder and the KCl powder selected in step 1 are mixed in a mass ratio of 0.5-0.85:1 of the mass of the anhydrous AlCl3 powder to the total mass of the anhydrous AlCl3 powder and the KCl powder to obtain a mixed powder of AlCl3 and KCl; Step 3, salt preparation: the mixed powder of AlCl3 and KCl obtained in step 2 is heated at a temperature of 300°C to 600°C for 72 hours under an argon atmosphere, and then the temperature is raised to 700°C to 800°C and HCl gas is introduced to obtain AlCl3&KCl eutectic salt; Step 4, heating reaction: mixing the AlCl3&KCl eutectic salt obtained in step 3 with the TiO2 powder and Mg particles selected in step 1, and then heating to 700°C~900°C under the condition of passing argon gas for 30min~180min to obtain a mixture of slag and metal; Step 5, pickling: the mixture of slag and metal obtained in step 4 is put into a hydrochloric acid solution for pickling, and then filtered to obtain metal powder; Step 6: Flotation: The metal powder obtained in step 5 is subjected to ball milling and flotation to obtain TiAl alloy powder.

2. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: The mass purity of the anhydrous AlCl3 powder, KCl powder, TiO2 powder and Mg particles in step 1 is greater than 99.5%, the particle size of the TiO2 powder is 200 mesh to 300 mesh, and the particle size of the Mg particles is 2 mm to 3 mm.

3. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: The mass ratio of the mass of the anhydrous AlCl3 powder in step 2 to the total mass of the anhydrous AlCl3 powder and the KCl powder is 0.65-0.

7.

4. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: The heating temperature under the argon atmosphere in step 3 is 300°C to 400°C.

5. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: The heating temperature in step 4 is 750°C to 800°C.

6. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: The mass fraction of the hydrochloric acid solution in step 5 is 3% to 5%, and the pickling time is 1h to 2h.

7. The method for preparing TiAl alloy powder by molten salt assisted metal thermal reduction according to claim 1, characterized in that: In the ball mill flotation described in step six, the mass ratio of balls, materials and water is 2:1:

5.

8. The method for preparing TiAl alloy powder by molten salt-assisted metal thermal reduction according to claim 1, characterized in that: The TiAl alloy powder in step six is ​​composed of the following elements in percentage by mass: Ti 40% to 70%, and the remainder is Al and inevitable impurities.

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