A nickel-niobium alloy and its preparation method

Abstract

The present invention provides a nickel-niobium alloy and a preparation method thereof, relating to the technical field of alloy materials. The preparation method of the nickel-niobium alloy provided by the present invention comprises the following steps: mixing niobium hydroxide, nickel hydroxide, and aluminum and performing vacuum roasting to obtain the nickel-niobium alloy; the mass ratio of the niobium hydroxide, nickel hydroxide, and aluminum is 3:(1.13-2.21):(1.02-1.15). The present invention uses niobium hydroxide and nickel hydroxide as raw materials. The two have similar melting points and densities and are easily decomposed, which facilitates the mixing of elemental niobium and nickel. Nickel and niobium are infinitely soluble in each other and are relatively uniform in grade compared to other materials. Furthermore, no conventional impurities (such as Fe and Si) are introduced during the preparation process of the present invention, which can improve the purity of the alloy. The present invention can produce a nickel-niobium alloy with uniform composition and high purity. The obtained nickel-niobium alloy is used in the production and smelting of high-temperature alloys, maximizing the comprehensive utilization of metallurgical resources while reducing the smelting cost of high-temperature alloys.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a nickel-niobium alloy and a preparation method thereof. Background Art

[0002] High-temperature alloys are increasingly used in the aerospace industry due to their exceptional combination of high strength and stiffness, weldability, high-temperature resistance, and corrosion resistance. Niobium, a key additive in high-temperature alloys, reduces intergranular corrosion caused by chromium carbide precipitation during heat treatment, improves resistance to pitting and crevice corrosion, and enhances high-temperature strength. However, elemental niobium is expensive and has a high melting point, making it unsuitable for industrial production. Furthermore, the product is prone to segregation. Therefore, nickel-niobium alloys with lower melting points are often used in high-temperature alloy production.

[0003] Currently, most nickel-niobium alloys are produced using the aluminothermic reduction process, using aluminum powder as a reducing agent to react with niobium pentoxide and nickel oxide. However, this method produces alloys with numerous inclusions and low purity. Some nickel-niobium alloys are also produced using elemental nickel and niobium in a vacuum induction furnace. However, due to the significant difference in density and melting point between elemental nickel and niobium, the resulting nickel-niobium alloys from this smelting method exhibit uneven composition. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a nickel-niobium alloy and a preparation method thereof. The nickel-niobium alloy prepared by the present invention has uniform composition and high purity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a nickel-niobium alloy, comprising the following steps:

[0007] Niobium hydroxide, nickel hydroxide and aluminum are mixed and calcined in vacuum to obtain a nickel-niobium alloy; the mass ratio of the niobium hydroxide, nickel hydroxide and aluminum is 3: (1.13-2.21): (1.02-1.15).

[0008] Preferably, the method for preparing niobium hydroxide comprises the following steps:

[0009] mixing niobium pentoxide with concentrated sulfuric acid and calcining the mixture to obtain a calcined product;

[0010] The calcined product is mixed with water to perform a first hydrothermal reaction to obtain niobium hydroxide.

[0011] Preferably, the mass concentration of the concentrated sulfuric acid is greater than 80%; the concentrated sulfuric acid is calculated as H2SO4, and the concentrated sulfuric acid is in excess relative to niobium pentoxide.

[0012] Preferably, the calcination temperature is 200-300° C., and the time is 2-3 hours; the first hydrothermal reaction temperature is 85-95° C., and the time is 1-2 hours.

[0013] Preferably, the method for preparing nickel hydroxide comprises the following steps:

[0014] Nickel sulfate, ammonia water and sodium hydroxide solution are mixed to carry out a second hydrothermal reaction to obtain nickel hydroxide.

[0015] Preferably, the amount of NH 3 ·H 2 O in the ammonia solution and the amount of NaOH in the sodium hydroxide solution are in excess relative to the nickel sulfate.

[0016] Preferably, the temperature of the second hydrothermal reaction is 55-65° C., and the time is 1-2 hours.

[0017] Preferably, after the second hydrothermal reaction, the method further comprises aging the obtained second hydrothermal reaction product, and the aging time is 24 to 36 hours.

[0018] Preferably, the vacuum calcination pressure is ≤10 Pa, the calcination temperature is 1650-1750° C., and the calcination time is 20-30 min.

[0019] The present invention provides a nickel-niobium alloy prepared by the preparation method described in the above technical solution, wherein the nickel-niobium alloy comprises 55.0-65.0% niobium by mass and the balance nickel.

[0020] The present invention provides a method for preparing a nickel-niobium alloy, comprising the following steps: mixing niobium hydroxide, nickel hydroxide, and aluminum and vacuum calcining the mixture to obtain a nickel-niobium alloy; the mass ratio of the niobium hydroxide, nickel hydroxide, and aluminum being 3:(1.13-2.21):(1.02-1.15). Compared with the prior art, the present invention has the following advantages: niobium hydroxide and nickel hydroxide are used as raw materials for preparing the nickel-niobium alloy. These two raw materials have similar melting points and densities and are easily decomposed, which facilitates the mixing of elemental niobium and nickel. Nickel and niobium are infinitely soluble in each other. After solidification, the alloy exhibits a microstructure consisting of a eutectic structure and a Ni6Nb7 intermetallic compound, which is relatively uniform compared to other grades. Furthermore, the preparation process of the present invention eliminates the introduction of conventional impurities (Fe, Si, etc.), thereby improving the purity of the alloy. The present invention can produce a nickel-niobium alloy with uniform composition and high purity. The resulting nickel-niobium alloy can be used in the production and smelting of high-temperature alloys, maximizing the comprehensive utilization of metallurgical resources while reducing the smelting cost of high-temperature alloys. DETAILED DESCRIPTION

[0021] The present invention provides a method for preparing a nickel-niobium alloy, comprising the following steps:

[0022] Niobium hydroxide, nickel hydroxide and aluminum are mixed and calcined in vacuum to obtain a nickel-niobium alloy; the mass ratio of the niobium hydroxide, nickel hydroxide and aluminum is 3: (1.13-2.21): (1.02-1.15).

[0023] The present invention has no particular requirements on the source of the niobium hydroxide, and it can be either commercially available or self-prepared. In an embodiment of the present invention, the preparation method of the niobium hydroxide preferably includes the following steps:

[0024] mixing niobium pentoxide with concentrated sulfuric acid and calcining the mixture to obtain a calcined product;

[0025] The calcined product is mixed with water to perform a first hydrothermal reaction to obtain niobium hydroxide.

[0026] The present invention mixes niobium pentoxide (Nb2O5) with concentrated sulfuric acid and calcines it to produce a calcined product. In the present invention, the mass concentration of the concentrated sulfuric acid is preferably greater than 80%; the concentrated sulfuric acid, calculated as H2SO4, is in excess relative to the niobium pentoxide. The method of mixing the niobium pentoxide and concentrated sulfuric acid is not particularly critical; it only requires ensuring uniform mixing. In the present invention, the calcination temperature is preferably 200-300°C, more preferably 250°C, and the calcination time is preferably 2-3 hours, more preferably 2.5 hours. The calcination is preferably carried out in a muffle furnace. In the present invention, if the calcination temperature is too low or the calcination time is too short, the reaction will be incomplete and the conversion rate of the niobium pentoxide will be low. If the calcination temperature is too high or the calcination time is too long, the material will volatilize and be wasted. In the present invention, the reaction equation involved in the calcination is: Nb2O5 + 2H2SO4 = Nb2O3(SO4)2 + 2H2O.

[0027] After obtaining the calcined product, the present invention mixes the calcined product with water to conduct a first hydrothermal reaction to produce niobium hydroxide. In the present invention, the water is preferably deionized water. The amount of water added is not particularly required, as long as it ensures the smooth progress of the hydrothermal reaction. In the present invention, the temperature of the first hydrothermal reaction is preferably 85-95°C, more preferably 90°C, and the reaction time is preferably 1-2 hours, more preferably 1.5 hours. The first hydrothermal reaction is preferably conducted in a hydrothermal reactor. In the present invention, if the temperature or time of the first hydrothermal reaction is too low, the reaction will be incomplete and the conversion rate of the calcined product will be low. If the temperature or time is too high, the material will volatilize and be wasted. In the present invention, the reaction formula involved in the first hydrothermal reaction is Nb2O3(SO4)2+7H2O=2Nb(OH)5↓+2H2SO4. After the first hydrothermal reaction, the present invention preferably cools the resulting hydrothermal reaction product, filters it, and washes it with water to produce niobium hydroxide.

[0028] The present invention has no particular requirements on the source of the nickel hydroxide, and can use commercially available products or prepare it yourself. In an embodiment of the present invention, the preparation method of the nickel hydroxide preferably includes the following steps:

[0029] Nickel sulfate, ammonia water and sodium hydroxide solution are mixed to carry out a second hydrothermal reaction to obtain nickel hydroxide.

[0030] Nickel sulfate (NiSO4) is a low-priced, but uncommon and difficult-to-utilize metallurgical resource. This invention uses nickel sulfate to extract the nickel element. The concentrations of the aqueous ammonia and sodium hydroxide solution are not particularly critical; concentrations familiar to those skilled in the art can be used. Preferably, the nickel sulfate and aqueous ammonia are added to a hydrothermal reactor, followed by the addition of the sodium hydroxide solution. In this invention, the NH3·H2O in the aqueous ammonia and the NaOH in the sodium hydroxide solution are in excess relative to the nickel sulfate.

[0031] In the present invention, the temperature of the second hydrothermal reaction is preferably 55-65°C, more preferably 60°C, and the time is preferably 1-2 hours, more preferably 1.5 hours; the second hydrothermal reaction is preferably carried out under stirring conditions. In the present invention, when the temperature of the second hydrothermal reaction is too low or the time is too short, the reaction is incomplete and the conversion rate of nickel sulfate is low. If the temperature is too high or the time is too long, the material will be volatilized and wasted. In the present invention, the reaction formula involved in the second hydrothermal reaction is: NiSO4+6NH3·H2O=[Ni(NH3)6]SO4+6H2O, [Ni(NH3)6]SO4+2NaOH=Ni(OH)2↓+6NH3+Na2SO4.

[0032] After the second hydrothermal reaction, the present invention preferably ages the obtained second hydrothermal reaction product, and the aging time is preferably 24 to 36 hours, more preferably 30 hours; if the aging time is too short, the component reaction or sedimentation will be insufficient, and if it is too long, time and energy will be wasted. After the aging, it is also preferably included that the obtained aged product is filtered, washed and dried in sequence to obtain nickel hydroxide; the drying temperature is preferably 90 to 100 ° C, more preferably 95 ° C, and the time is preferably 6 to 8 hours, more preferably 7 hours; if the drying temperature is too low or the time is too short, the water in Ni (OH) 2 is not dried sufficiently, and if the drying time is too long or the temperature is too high, waste or product decomposition will result.

[0033] After obtaining niobium hydroxide and nickel hydroxide, the present invention mixes the niobium hydroxide, nickel hydroxide, and aluminum and vacuum calcines them to produce a nickel-niobium alloy. In the present invention, the mass ratio of the niobium hydroxide, nickel hydroxide, and aluminum is 3:(1.13-2.21):(1.02-1.15). The present invention preferably crushes the niobium hydroxide and nickel hydroxide before uniformly mixing them with the aluminum. In the present invention, the vacuum degree of the vacuum calcination is preferably ≤10 Pa, more preferably 8-9 Pa, the calcination temperature is preferably 1650-1750°C, more preferably 1700°C, and the calcination time is preferably 20-30 minutes, more preferably 25 minutes. The vacuum calcination is preferably performed in a high-temperature vacuum resistance furnace. In the present invention, calcining for too short a time or at too low a temperature will result in incomplete reaction and the inclusion of moisture in the alloy, while calcining for too long a time or at too high a temperature will result in waste. In the present invention, the reaction equation involved in the vacuum calcination is: Nb(OH)5+Ni(OH)2+Al=NbNi+Al2O3+H2O↑. During the vacuum roasting process, nickel hydroxide and niobium hydroxide have low melting points and are easily melted into a liquid state. At the same time, nickel hydroxide and niobium hydroxide, as well as the nickel-niobium alloy after the reaction, have high densities and are divided into upper and lower layers with the generated Al2O3. Al2O3 is easily separated to obtain a nickel-niobium alloy. In addition, compared with the production of nickel-niobium alloy by aluminothermic reduction, the present invention adds less aluminum and generates less Al2O3.

[0034] The present invention provides a nickel-niobium alloy prepared by the preparation method described in the above technical solution. The nickel-niobium alloy comprises, by weight, 55.0-65.0% niobium and the balance nickel. The niobium content is preferably 58.0-62.0%, more preferably 60.0%. The nickel-niobium alloy provided by the present invention has a uniform composition and high purity and is suitable for the production and smelting of high-temperature alloys, maximizing the comprehensive utilization of metallurgical resources while reducing the smelting cost of high-temperature alloys.

[0035] In order to further illustrate the present invention, the nickel-niobium alloy and the preparation method thereof provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of protection of the present invention.

[0036] Example 1

[0037] (1) 30 kg of Nb2O5 was mixed with excess concentrated sulfuric acid (concentrated sulfuric acid concentration>80%) and then calcined in a muffle furnace to obtain a calcined product at a temperature of 250°C and a calcination time of 2.5 h;

[0038] (2) adding the calcined product and excess deionized water into a hydrothermal reactor for hydrothermal reaction, cooling the hydrothermal reaction product, filtering it, and washing it with water to obtain niobium hydroxide; wherein the hydrothermal temperature is 90° C., and the hydrothermal time is 1.5 h;

[0039] (3) adding 30 kg of nickel sulfate and excess ammonia water into a hydrothermal reactor, and then adding excess sodium hydroxide solution, and carrying out a hydrothermal reaction under electromagnetic stirring, wherein the hydrothermal temperature is 60 ° C, and the hydrothermal time is 1.5 hours; the hydrothermal reaction product is cooled and aged, and then filtered, washed with water, and dried to obtain nickel hydroxide, wherein the aging time is 30 hours, the drying temperature is 95 ° C, and the drying time is 7 hours;

[0040] (4) 30 kg of niobium hydroxide and 16.47 kg of nickel hydroxide were crushed, mixed evenly with 10.76 kg of aluminum, and then placed in a high-temperature vacuum resistance furnace for vacuum roasting at a vacuum of 8 Pa, a temperature of 1700°C, and a time of 25 minutes. After cooling, a nickel-niobium alloy was obtained.

[0041] Example 2

[0042] (1) 30 kg of Nb2O5 was mixed evenly with excess concentrated sulfuric acid (concentrated sulfuric acid concentration>80%), and then calcined in a muffle furnace to obtain a calcined product, wherein the calcination temperature was 200°C and the calcination time was 3 hours;

[0043] (2) adding the calcined product and excess deionized water into a hydrothermal reactor for hydrothermal reaction, cooling the hydrothermal reaction product, filtering it, and washing it with water to obtain niobium hydroxide; wherein the hydrothermal temperature is 95° C. and the hydrothermal time is 1 hour;

[0044] (3) adding 30 kg of nickel sulfate and excess ammonia water into a hydrothermal reactor, and then adding excess sodium hydroxide solution, and carrying out a hydrothermal reaction under electromagnetic stirring, wherein the hydrothermal temperature is 65 ° C, and the hydrothermal time is 1 hour; the hydrothermal reaction product is cooled and aged, and then filtered, washed with water, and dried to obtain nickel hydroxide, wherein the aging time is 36 hours, the drying temperature is 90 ° C, and the drying time is 8 hours;

[0045] (4) 30 kg of niobium hydroxide and 20.21 kg of nickel hydroxide were crushed, mixed evenly with 11.48 kg of aluminum, and then placed in a high-temperature vacuum resistance furnace for vacuum roasting at a vacuum of 10 Pa, a temperature of 1650°C, and a time of 30 minutes. After cooling, a nickel-niobium alloy was obtained.

[0046] Example 3

[0047] (1) 30 kg of Nb2O5 was mixed with excess concentrated sulfuric acid (concentrated sulfuric acid concentration>80%) and then calcined in a muffle furnace to obtain a calcined product at a temperature of 300°C and a calcination time of 2 h;

[0048] (2) adding the calcined product and excess deionized water into a hydrothermal reactor for hydrothermal reaction, cooling the hydrothermal reaction product, filtering it, and washing it with water to obtain niobium hydroxide; wherein the hydrothermal temperature is 85° C., and the hydrothermal time is 2 h;

[0049] (3) adding 30 kg of nickel sulfate and excess ammonia water into a hydrothermal reactor, then adding excess sodium hydroxide solution, and carrying out a hydrothermal reaction under electromagnetic stirring, wherein the hydrothermal temperature is 55 ° C, and the hydrothermal time is 2 h; the hydrothermal reaction product is cooled and aged, and then filtered, washed with water, and dried to obtain nickel hydroxide, wherein the aging time is 24 h, the drying temperature is 100 ° C, and the drying time is 6 h;

[0050] (4) 30 kg of niobium hydroxide and 13.30 kg of nickel hydroxide were crushed, mixed evenly with 10.15 kg of aluminum, and then placed in a high-temperature vacuum resistance furnace for vacuum roasting at a vacuum of 9 Pa, a temperature of 1750°C, and a time of 20 minutes. After cooling, a nickel-niobium alloy was obtained.

[0051] The nickel-niobium alloys prepared in Examples 1 to 3 were made into powders and chemical composition analysis was performed at different random locations. The results are shown in Tables 1 to 3 (% in Tables 1 to 3 represents mass percentage).

[0052] Table 1 Chemical composition of nickel-niobium alloy according to Example 1 of the present invention

[0053]

[0054]

[0055] Table 2 Chemical composition of nickel-niobium alloy according to Example 2 of the present invention

[0056] Location Ni% Nb% S％ H％ O％ N％ Na% Al％ 1 margin 55.00 0.0011 0.011 0.013 0.046 0.0017 0.034 2 margin 55.02 0.0011 0.012 0.012 0.046 0.0016 0.035 3 margin 55.07 0.0016 0.012 0.012 0.043 0.0016 0.031 4 margin 55.00 0.0009 0.012 0.013 0.047 0.0016 0.037 5 margin 55.06 0.0018 0.011 0.012 0.044 0.0016 0.032 6 margin 55.12 0.0020 0.012 0.011 0.046 0.0019 0.032 Extremely poor / 0.12 0.0011 0.001 0.002 0.004 0.0003 0.006

[0057] Table 3 Chemical composition of nickel-niobium alloy according to Example 3 of the present invention

[0058] Location Ni% Nb% S％ H％ O％ N％ Na% Al％ 1 margin 64.96 0.0016 0.013 0.013 0.042 0.0016 0.034 2 margin 64.99 0.0009 0.012 0.014 0.050 0.0016 0.035 3 margin 65.00 0.0014 0.012 0.012 0.043 0.0016 0.031 4 margin 65.00 0.0011 0.013 0.012 0.047 0.0018 0.032 5 margin 64.93 0.0018 0.011 0.012 0.043 0.0016 0.036 6 margin 65.00 0.0016 0.012 0.011 0.041 0.0019 0.032 Extremely poor / 0.07 0.0009 0.001 0.003 0.009 0.0003 0.005

[0059] It can be seen from the above examples that the present invention uses niobium pentoxide and nickel sulfate as basic raw materials to prepare niobium hydroxide and nickel hydroxide, and the nickel-niobium alloy prepared from niobium hydroxide and nickel hydroxide has uniform composition and high purity.

[0060] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-niobium alloy, characterized in that: The following steps are involved: Niobium hydroxide, nickel hydroxide and aluminum are mixed and calcined in vacuum to obtain a nickel-niobium alloy; the mass ratio of the niobium hydroxide, nickel hydroxide and aluminum is 3: (1.13-2.21): (1.02-1.15).

2. The preparation method according to claim 1, characterized in that The preparation method of niobium hydroxide comprises the following steps: mixing niobium pentoxide with concentrated sulfuric acid and calcining the mixture to obtain a calcined product; The calcined product is mixed with water to perform a first hydrothermal reaction to obtain niobium hydroxide.

3. The preparation method according to claim 2, characterized in that The mass concentration of the concentrated sulfuric acid is greater than 80%; the concentrated sulfuric acid is calculated as H2SO4, and the concentrated sulfuric acid is excessive relative to niobium pentoxide.

4. The preparation method according to claim 2, characterized in that The calcination temperature is 200-300° C., and the time is 2-3 hours; the first hydrothermal reaction temperature is 85-95° C., and the time is 1-2 hours.

5. The preparation method according to claim 1, characterized in that The preparation method of the nickel hydroxide comprises the following steps: Nickel sulfate, ammonia water and sodium hydroxide solution are mixed to carry out a second hydrothermal reaction to obtain nickel hydroxide.

6. The preparation method according to claim 5, characterized in that The NH 3 ·H 2 O in the ammonia solution and the NaOH in the sodium hydroxide solution are in excess relative to the nickel sulfate.

7. The preparation method according to claim 5, characterized in that The temperature of the second hydrothermal reaction is 55-65° C., and the time is 1-2 hours.

8. The preparation method according to claim 5 or 7, characterized in that After the second hydrothermal reaction, the method further includes aging the obtained second hydrothermal reaction product, wherein the aging time is 24 to 36 hours.

9. The preparation method according to claim 1, characterized in that The vacuum degree of the vacuum calcination is ≤10Pa, the calcination temperature is 1650-1750°C, and the calcination time is 20-30min.

10. The nickel-niobium alloy prepared by the preparation method according to any one of claims 1 to 9, wherein the nickel-niobium alloy comprises 55.0 to 65.0% by mass of niobium and the balance of nickel.

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