Preparation method of niobium-titanium alloy

Abstract

The invention discloses a niobium-titanium alloy preparation method which comprises the following steps: S1, mixing niobium oxide powder, titanium compound powder and metal reducing agent powder according to a set proportion to obtain a mixture; s2, performing thermal reduction reaction on the mixture in a protective atmosphere, and cooling to obtain the niobium-titanium alloy containing a reduction byproduct; and S3, the niobium-titanium alloy containing the reduction by-product is subjected to acid pickling leaching, and after filtering, the niobium-titanium alloy is obtained. According to the method, the niobium compound and the titanium compound are directly used as raw materials, metal extraction and alloying are carried out at the same time, and the method has the advantage of being short in technological process; the heat effect of metal thermal reduction is utilized to promote diffusion of the two refractory metals, the alloying effect is enhanced, and the long-time high-temperature and high-pressure alloying procedure in a traditional process is avoided; the reduced niobium and titanium are rapidly alloyed along with the chemical reaction, segregation caused by the density difference of the two metal elementary substances is avoided, and the form and uniformity of the alloy can be obtained by changing technological parameters and regulating and controlling.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy smelting, and in particular relates to a method for preparing a niobium-titanium alloy. Background Art

[0002] Niobium-titanium alloy has good superconductivity in medium and low magnetic fields, electrical and thermal conductivity, high melting point, corrosion resistance, and machinability, and is widely used in superconductivity, medical treatment, target materials, and other fields. Niobium-titanium superconducting materials are currently the most widely used low-temperature superconducting materials. The application of Nb-Ti superconductors is of great significance in solving energy problems (such as the ITER International Thermonuclear Fusion Device), disease diagnosis and treatment (medical magnetic resonance imaging device MRI) and physics research (such as the LHC European Linear Superconducting Accelerator).

[0003] At present, the main method used to prepare niobium-titanium alloy is thermal reduction-powder metallurgy. First, the compounds of the two metals are reduced by aluminum heat and crushed to form metal elements. Then, the niobium powder and titanium powder are hot pressed at high temperature for a long time to make the two metals achieve alloying through diffusion. This method requires a long process to prepare niobium-titanium alloy from niobium compounds and titanium compounds, and the byproduct aluminum oxide is difficult to separate from the alloy; secondly, due to the high melting points of niobium and titanium, the solid-solid diffusion rate of the two metals during hot pressing is slow. It takes a long time to achieve full alloying, which will lead to high energy consumption of the process; and during hot pressing, niobium and titanium powders are easily oxidized at high temperatures for a long time due to their high surface activity, resulting in reduced alloy purity; in addition, the density of niobium and titanium is quite different, and the mass fractions of niobium and titanium at different positions in the alloy formed by hot pressing are significantly different. The niobium-titanium alloy obtained by this method can generally only be a block, and the organization and morphology are difficult to control. Summary of the invention

[0004] In view of this, some embodiments disclose a method for preparing a niobium-titanium alloy, comprising:

[0005] S1. Mixing niobium oxide powder, titanium compound powder and metal reducing agent powder according to a set ratio to obtain a mixture;

[0006] S2, subjecting the mixture to a thermal reduction reaction in a protective atmosphere, and cooling the mixture to obtain a niobium-titanium alloy containing reduction byproducts;

[0007] S3, pickling and leaching the niobium-titanium alloy containing the reduction by-products, filtering and obtaining the niobium-titanium alloy.

[0008] In some embodiments of the method for preparing niobium-titanium alloy, step S2 specifically includes:

[0009] Heat the mixture to 800-1200°C in a protective atmosphere and keep it warm for 2-10 hours.

[0010] In some embodiments of the method for preparing niobium-titanium alloy, step S2 specifically includes:

[0011] Adding magnesium and potassium chlorate to the mixture, wherein magnesium serves as an ignition agent and potassium chlorate serves as an exothermic agent;

[0012] The mixture is ignited in a protective atmosphere to trigger the reduction reaction.

[0013] In the preparation method of niobium-titanium alloy disclosed in some embodiments, the titanium compound powder is potassium fluorotitanate or titanium oxide.

[0014] In the preparation method of niobium-titanium alloy disclosed in some embodiments, the metal reducing agent powder is magnesium or calcium.

[0015] In the preparation method of niobium-titanium alloy disclosed in some embodiments, the amount of metal reducing agent powder added is 2 to 5 times the amount required for reducing niobium oxide powder and titanium compound powder.

[0016] In the method for preparing niobium-titanium alloy disclosed in some embodiments, the solution used for pickling in step S3 is a combination of one or more of hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid.

[0017] In the method for preparing niobium-titanium alloy disclosed in some embodiments, the niobium-titanium alloy obtained in step S3 is in the form of powder or block.

[0018] The preparation method of the niobium-titanium alloy disclosed in the embodiment of the present invention directly uses niobium compounds and titanium compounds as raw materials, and metal extraction and alloying are carried out simultaneously, which has the advantage of a short process flow; the thermal effect of metal thermal reduction is utilized to promote the diffusion of the two refractory metals, strengthen the alloying effect, avoid the long-term high-temperature and high-pressure alloying process in the traditional process, and significantly reduce energy consumption; and, due to the extremely fast thermal reduction rate, the reduced niobium and titanium are rapidly alloyed along with the progress of the chemical reaction, avoiding the segregation caused by the density difference of the two metal elements, and the morphology and uniformity of the alloy can be obtained by changing the process parameters. The alloy can be in the form of powder or block. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 SEM image of niobium-titanium alloy of Example 1;

[0020] Figure 2 Mapping diagram of niobium-titanium alloy in Example 2. DETAILED DESCRIPTION

[0021] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0022] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0023] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. The numerical data represented or presented in the range format herein are used only for convenience and brevity, and should therefore be flexibly interpreted as including not only the values ​​clearly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, the numerical range of "1-5%" should be interpreted as including not only the clearly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Therefore, independent values ​​such as 2%, 3.5% and 4% and sub-ranges such as 1%-3%, 2%-4% and 3%-5% are included in this numerical range. This principle also applies to the range of only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0024] In this document, including in the claims, transitional words such as "comprises," "includes," "with," "having," "containing," "involving," "accommodating," etc. are understood to be open-ended, i.e., meaning "including but not limited to." Only the transitional words "consisting of" and "composed of" are closed transitional words.

[0025] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0026] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be arbitrarily combined, and the obtained technical solutions belong to the contents disclosed in the embodiments of the present application. It should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like mentioned in the present application indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the technical features and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention, unless it conflicts with the context. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance, unless it conflicts with the context.

[0027] In some embodiments, a method for preparing a niobium-titanium alloy comprises:

[0028] S1. Mix niobium oxide powder, titanium compound powder and metal reducing agent powder according to a set ratio to obtain a mixture; generally, the set ratio of niobium oxide powder, titanium compound powder and metal reducing agent powder is determined according to the content of niobium and titanium in the target alloy product; for example, if the mass fraction ratio of niobium to titanium in the target alloy is 1:1, the addition amount of niobium oxide and titanium compound is calculated according to this ratio, and then the addition amount of metal reducing agent is determined according to the addition amount of niobium oxide and titanium compound;

[0029] S2. subjecting the mixed material to a thermal reduction reaction in a protective atmosphere, and cooling the mixed material to obtain a niobium-titanium alloy containing reduction byproducts; generally, the reduction reaction involved includes:

[0030] A+ TiO2=Ti+2AO (1)

[0031] 2A+ K2TiF6=Ti+2KF+2AF2 (2)

[0032] 5A+ Nb2O5=2Nb+5AO (3) In the formula, A is Mg or Ca;

[0033] S3, pickling and leaching the niobium-titanium alloy containing the reduction byproducts, filtering and obtaining the niobium-titanium alloy; wherein the reduction byproducts are AO or KF, AF2. During the pickling and leaching process, the reduction byproducts in the niobium-titanium alloy are removed from the niobium-titanium alloy and dissolved in the pickling solution; for example, when HCl solution is used as the pickling solution, AO+2HCl=H2O+ACl2.

[0034] In some embodiments, when preparing niobium-titanium alloy powder, step S2 specifically includes:

[0035] Heat the mixture to 800-1200℃ in a protective atmosphere and keep it warm for 2-10h. The heating temperature and holding time are the key to adjusting the powder morphology. If the temperature is too low, the mixture will not be completely reduced, and if it is too high, the powder will be severely sintered.

[0036] In some embodiments, when preparing a niobium-titanium alloy block, step S2 specifically includes:

[0037] Adding magnesium and potassium chlorate to the mixture, wherein magnesium is used as an ignition agent and potassium chlorate is used as an exothermic agent; the amount of magnesium added is determined according to the amount of niobium oxide and titanium compound added, and the amount of potassium chloride added is 5-15% of the mixture;

[0038] The mixture is ignited in a protective atmosphere to trigger the reduction reaction. This method does not require heating throughout the process, and relies entirely on the heat released by the combustion of magnesium and potassium chlorate to maintain the reduction reaction and alloying. Therefore, it can also be called a self-propagating method. This method avoids the long-term, high-temperature and high-pressure alloying process in traditional processes, and can significantly reduce energy consumption.

[0039] In some embodiments, the titanium compound powder is potassium fluorotitanate or titanium oxide.

[0040] In some embodiments, when the titanium compound powder is potassium fluorotitanate, the reduction byproducts KF and AF2 can also be removed by high-temperature distillation.

[0041] In some embodiments, the metal reducing agent powder is magnesium or calcium. Generally, when magnesium is used as the metal reducing agent powder, magnesium gasification is serious at high temperature, which may easily cause incomplete reduction of the compound, and sufficient magnesium needs to be added to promote deep reduction. Sufficient magnesium can effectively reduce the content of impurities such as oxygen in the product.

[0042] In some embodiments, the amount of the metal reducing agent powder added is 2 to 5 times the amount required to reduce the niobium oxide powder and the titanium compound powder.

[0043] In some embodiments, the solution used for pickling in step S3 is a combination of one or more of hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid.

[0044] In some embodiments, the niobium-titanium alloy obtained in step S3 is in the form of powder or block.

[0045] The technical details are further illustrated below in conjunction with embodiments.

[0046] Example 1

[0047] The method for preparing the niobium-titanium alloy disclosed in Example 1 comprises:

[0048] S1, Morby X Nb2O5 :X TiO2=48:93, weigh niobium pentoxide powder and titanium oxide powder, ensure that the mass ratio of niobium and titanium in the two compounds is 1:1, and then weigh magnesium powder, where the addition amount of magnesium powder is X Mg =2×(5X Nb2O5 +2X TiO2 ), mixing to obtain a mixture;

[0049] S2, heating the mixture to 1000° C. in a protective atmosphere, keeping the temperature for 3 hours, and cooling to obtain a niobium-titanium alloy containing magnesium oxide;

[0050] S3. Pickling and leaching the niobium-titanium alloy containing magnesium oxide in a hydrochloric acid solution for 2 hours to separate the magnesium oxide from the niobium-titanium alloy, and filtering to obtain niobium-titanium alloy powder.

[0051] Figure 1 This is a SEM image of the niobium-titanium alloy disclosed in Example 1. Figure 1 As shown, in the niobium-titanium alloy powder prepared in Example 1, the mass fractions of niobium and titanium elements are very similar, and an ideal niobium-titanium alloy powder is obtained.

[0052] Example 2

[0053] The method for preparing the niobium-titanium alloy disclosed in Example 2 comprises:

[0054] S1, Morby X Nb2O5 :X TiO2 =48:93, weigh niobium pentoxide powder and titanium oxide powder, ensure that the mass ratio of niobium and titanium in the two compounds is 1:1, and then weigh calcium powder, where the addition amount of calcium powder is X Ca =5×(5X Nb2O5 +2X TiO2 ), mixing to obtain a mixture;

[0055] S2, heating the mixture to 1000° C. in a protective atmosphere, keeping the temperature for 10 hours, and cooling to obtain a niobium-titanium alloy containing calcium oxide;

[0056] S3. Pickling and leaching the niobium-titanium alloy containing calcium oxide in a hydrochloric acid solution for 2 hours to separate the calcium oxide from the niobium-titanium alloy, and filtering to obtain niobium-titanium alloy powder.

[0057] Figure 2 This is the mapping diagram of the niobium-titanium alloy disclosed in Example 2. Figure 2 As shown, the distribution of niobium and titanium elements in different regions of the niobium-titanium alloy powder prepared in Example 2 is relatively uniform, and the overall distribution state of niobium and titanium elements is consistent, and the mass fractions of the two are close, which is an ideal niobium-titanium alloy powder.

[0058] The preparation method of the niobium-titanium alloy disclosed in the embodiment of the present invention directly uses niobium compounds and titanium compounds as raw materials, and metal extraction and alloying are carried out simultaneously, which has the advantage of a short process flow; the thermal effect of metal thermal reduction is utilized to promote the diffusion of the two refractory metals, strengthen the alloying effect, avoid the long-term high-temperature and high-pressure alloying process in the traditional process, and significantly reduce energy consumption; and, due to the extremely fast thermal reduction rate, the reduced niobium and titanium are rapidly alloyed along with the progress of the chemical reaction, avoiding the segregation caused by the density difference of the two metal elements, and the morphology and uniformity of the alloy can be obtained by changing the process parameters. The alloy can be in the form of powder or block.

[0059] The technical solutions disclosed in the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the present invention. Any conventional changes, substitutions or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a niobium-titanium alloy, characterized in that: include: S1. Mixing niobium oxide powder, titanium compound powder and metal reducing agent powder according to a set ratio to obtain a mixture; S2, subjecting the mixture to a thermal reduction reaction in a protective atmosphere, and cooling the mixture to obtain a niobium-titanium alloy containing reduction byproducts; S3, pickling and leaching the niobium-titanium alloy containing the reduction by-products, filtering and obtaining the niobium-titanium alloy.

2. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: Step S2 specifically includes: Heat the mixture to 800-1200°C in a protective atmosphere and keep it warm for 2-10 hours.

3. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: Step S2 specifically includes: Adding magnesium and potassium chlorate to the mixture, wherein magnesium serves as an ignition agent and potassium chlorate serves as an exothermic agent; The mixture is ignited in a protective atmosphere to trigger the reduction reaction.

4. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: The titanium compound powder is potassium fluorotitanate or titanium oxide.

5. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: The metal reducing agent powder is magnesium or calcium.

6. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: The amount of the metal reducing agent powder added is 2 to 5 times the amount required for reducing the niobium oxide powder and the titanium compound powder.

7. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: The solution used for pickling in step S3 is a combination of one or more of hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid.

8. The method for preparing niobium-titanium alloy according to claim 1, characterized in that: The niobium-titanium alloy obtained in step S3 is in the form of powder or block.

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