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Niobium metal original name. Application of niobium in metallurgy and industry. Alternative production methods

The production of niobium along with tantalum, as well as tantalonium-obium alloys, is of great economic importance from the point of view of the integrated use of both valuable metals.
In many cases, instead of tantalum, with the same effect, you can use niobium, which is similar in properties, or alloys of tantalum with niobium, since these metals form a continuous series of solid solutions, the properties of which are close to the properties of the original metals.
An alloy of tantalum with niobium can be obtained by mixing separately obtained tantalum and niobium powders, followed by pressing the mixture and sintering in a vacuum, as well as by simultaneous joint reduction of a mixture of tantalum and niobium compounds, for example, a mixture of complex fluorides K2TaF7 and K2NbF7, a mixture of chlorides, a mixture of oxides, etc. . P.
Typically, when using the hydrofluoric acid method for separating tantalum and niobium, the latter is separated in the form of fluoroxyniobate K2NbOF5*H2O.
This salt is not suitable for reduction with sodium for two reasons:
a) water of crystallization, which is part of the said salt, reacting with sodium can lead to an explosion,
b) oxygen, which is part of the salt and associated with niobium, is not reduced by sodium and remains in the form of an oxide impurity in the reduction product.
Therefore, potassium fluoroxyniobate must be recrystallized through a solution of hydrofluoric acid with a HF concentration above 10%, resulting in the formation of the K2NbF7 salt, suitable for reduction with sodium.
Niobium can also be produced by electrolysis under conditions similar to those described for tantalum production. A lower current efficiency is noted than in the electrolytic production of tantalum, as well as difficulties associated with the noticeable solubility of niobium compounds of different valencies in the electrolyte.
Electrolysis is also possible from a mixed bath containing a mixture of Ta2O5 + Nb2O5 as decomposing components and K2TaF7 as a solvent. In this case, an alloy of niobium with tantalum is obtained.
To obtain niobium, a method of carbon reduction of niobium pentoxide in vacuum was proposed.

Reduction of niobium pentoxide with carbon


To obtain niobium, K. Bohlke developed a method for the reduction of niobium pentoxide with niobium carbide in vacuum according to the reaction:

Essentially this process comes down to the reduction of niobium pentoxide with carbon.
Due to the high chemical strength of niobium pentoxide, reduction with carbon at atmospheric pressure requires high temperature (about 1800-1900°), which can be obtained in a graphite tube furnace. Niobium has a high affinity for carbon (free energy of formation of niobium carbide -ΔF° = 38.2 kcal ), therefore, in the presence of carbon gases in the furnace and at a high rate of diffusion in the solid phase, developing at such a high temperature, niobium turns out to be contaminated with niobium carbide, even if the charge is prepared based on the reaction

In a vacuum, the reduction reaction with carbon occurs at a lower temperature (1600-1700°),
Briquettes are prepared from a mixture of niobium pentoxide and soot, taken in stoichiometric ratios based on the reaction

Rolling is carried out at 1800-1900° in a graphite tube furnace in a protective atmosphere (hydrogen, argon) or in a vacuum at a temperature of 1600° until the evolution of CO ceases. The resulting product is slightly sintered briquettes consisting of particles of powdered gray carbide. The carbide is ground into powder in a ball mill and mixed with pentoxide in ratios corresponding to reaction (1). Briquettes of the Nb2O5 + NbC mixture are again calcined in vacuum at a temperature of about 1600°.
To ensure the removal of carbon in the form of CO, a small excess of niobium pentoxide should be added to the Nb2O5 + NbC mixture. In the subsequent operation of high-temperature sintering (welding) of bars pressed from powdered metal niobium, excess niobium pentoxide is removed, since niobium oxides (like tantalum) volatilize in a vacuum at a temperature below the melting point of the metal
Due to the inevitable time spent on creating a vacuum and cooling the product in it, the productivity of a vacuum furnace in the production of initial niobium carbide is much lower than the productivity of a graphite tube furnace operating at atmospheric pressure, in which a continuous process can be carried out by moving cartridges with briquettes of a mixture of Nb2O5 + C. Therefore, it is more expedient to obtain NbC continuously in a graphite tube furnace at atmospheric pressure, although at temperatures of 1800-1900°.
It would be possible to obtain metallic niobium in a vacuum furnace directly by reacting pentoxide with soot according to reaction (2) with a slight excess of Nb2O5 in the charge. However, when loading a mixture of Nb2O5 + 5NbC into a vacuum furnace, its productivity increases significantly compared to loading a mixture of Nb2O5 + 5C, since the Nb2O5 + SNbC mixture contains niobium (82.4%) 1.5 times more than the Nb2O5 + 5C mixture ( 57.2%) In addition, the first mixture has an additive specific gravity 1.7 times greater than the second mixture (6.25 g/cm3 and 3.7 g/cm3, respectively).
In addition, it must be taken into account that niobium carbide, which makes up the predominant part of the Nb2O5 + 5NbC mixture, is coarser-grained than dispersed Nb2O5 and soot powders, which is an additional reason for the greater bulk weight of the Nb2O5 + 5NbC mixture than the Nb2O5 + 5C mixture.
As a result of all this, a unit volume of the cartridge can accommodate 2.5-3 times more material (based on niobium content) in the form of briquettes of the Nb2O5 + 5NbC mixture than briquettes of the Nb2O5 + 5C mixture.
Bolke's work does not provide sufficiently strong evidence for the need to strictly adhere to his recommended composition of the Nb2O5 + 5NbC mixture loaded into a vacuum furnace.
By calcining a mixture of Nb2O5 + 5C in a coal-tube furnace at atmospheric pressure, a product similar in composition to metallic niobium with a small admixture of carbon can be obtained with high productivity (in a continuous process). This niobium-rich powder with high specific and bulk gravity can then be mixed with an appropriate amount of Nb2O5 (with a slight excess of Nb2O5 relative to the equivalent carbon impurity content of the niobium) and the briquetted mixture calcined in a vacuum oven to remove carbon in the form of CO.
With this option, the capacity, and therefore the productivity, of the vacuum furnace will be greatest. The small remaining excess Nb2O5 will evaporate during further high-temperature sintering of niobium, and the latter will turn into a compact malleable metal
When using low-carbon niobium instead of niobium carbide to react with pentoxide, some technological complications may arise. The fact is that when producing low-carbon niobium at atmospheric pressure in the reaction space of a graphite-tube furnace, the presence of nitrogen impurities from the air that can enter the furnace is always possible. Niobium, having a high affinity for nitrogen, actively absorbs it. When producing niobium carbide, the possibility of contamination of the product with nitrogen is much less due to the greater affinity of niobium for carbon than for nitrogen.
Therefore, the production of metallic niobium when using low-carbon niobium as a starting material is complicated by the need to create conditions that exclude the possibility of nitrogen entering the reaction space, which is difficult to achieve in a graphite tube furnace freely connected to the atmosphere. To remove nitrogen from the furnace, it is necessary to carefully fill the furnace with pure hydrogen or argon, maintain the tightness of the casing, avoid drawing air into the reaction tube when loading cartridges with a mixture of Nb2O5 + 5C into it and when unloading niobium, etc.
Therefore, the question of the advantages of the option of preliminary production of niobium carbide or low-carbon niobium at atmospheric pressure (followed by calcination of these products in a mixture with Nb2O5 in a vacuum) can be resolved by practical possibilities in each individual case.
The advantages of the niobium carbon reduction process according to one of the described options are: the use of a cheap reducing agent in the form of soot and high direct extraction of niobium into the finished metal
The similarity of the properties of tantalum and niobium oxides allows the described method to be used to obtain malleable tantalum.

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Niobium

NIOBIUM-I; m.[lat. Niobium] Chemical element (Nb), a hard, refractory and malleable metal of a grayish-white color (used in the production of chemical-resistant and heat-resistant steels).

◁ Niobium; niobium, -aya, -oe.

niobium

(lat. Niobium), chemical element of group V of the periodic table. Named after Niobe - the daughter of the mythological Tantalus (the similarity of the properties of Nb and Ta). Light gray refractory metal, density 8.57 g/cm 3, t mp 2477°C, transition temperature to the superconducting state 9.28 K. Chemically very resistant. Minerals: pyrochlore, columbite, loparite, etc. A component of chemically resistant and heat-resistant steels, from which parts of rockets, jet engines, chemical and oil refining equipment are made. Niobium and its alloys are used to coat fuel elements of nuclear reactors. Nb 3 Sn stannide, Nb 3 Ge germanide, alloys of niobium with Sn, Ti and Zr are used for the manufacture of superconducting solenoids (Nb 3 Ge is a superconductor with a transition temperature to the superconducting state of 23.2 K).

NIOBIUM

NIOBIUM (lat. Niobium, on behalf of Niobe (cm. NIOBE)), Nb (pronounced "niobium"), a chemical element with atomic number 41, atomic mass 92.9064. Natural niobium consists of one stable isotope, 93 Nb. Configuration of two outer electronic layers 4 s 2 p 6 d 4 5s 1 . Oxidation states +5, +4, +3, +2 and +1 (valences V IV, III, II and I). Located in group VB, in the 5th period of the periodic table of elements.
Atomic radius 0.145 nm, radius of Nb 5+ ion - from 0.062 nm (coordination number 4) to 0.088 nm (8), Nb 4+ ion - from 0.082 to 0.092 nm, Nb 3+ ion - 0.086 nm, Nb 2+ ion - 0.085 nm. The sequential ionization energies are 6.88, 14.32, 25.05, 38.3 and 50.6 eV. Electron work function 4.01 eV. Electronegativity according to Pauling (cm. PAULING Linus) 1,6.
History of discovery
Discovered in 1801 by C. Hatchet (cm. HATCHET Charles). While examining a black mineral sent from America, he isolated the oxide of a new element, which he called columbium, and the mineral containing it - columbite. A year later, from the same mineral A. G. Ekeberg (cm. ECKEBERG Anders Gustav) isolated another oxide, which he named tantalum (cm. TANTALUM (chemical element)). The properties of columbium and Ta were very similar, and they were considered as one element for a very long time. In 1844 G. Rose (cm. ROSE (German scientists, brothers)) proved that these are two different elements. He kept the name tantalum, and the other called niobium. It was only in 1950 that the IUPAC (World Organization of Chemists) finally assigned the name niobium to element No. 41. Metallic Nb was first obtained in 1866 by K. Blomstrand (cm. BLOMSTRAND Christian Wilhelm).
Being in nature
The content in the earth's crust is 2·10 -3% by weight. Niobium is not found in free form; it accompanies tantalum in nature. Of the ores, the most important are columbite-tantalite. (cm. COLUMBITE)(Fe,Mn)(Nb,Ta) 2 O 6, pyrochlore (cm. PYROCHLOR) and loparit (cm. LOPARIT).
Receipt
About 95% of Nb is obtained from pyrochlore, columbite-tantalite and loparite ores. Ores are enriched using gravity methods and flotation (cm. FLOTATION). Concentrates containing up to 60% Nb 2 O 5 are processed to ferroniobium (an alloy of iron and niobium), pure Nb 2 O 5 or NbCl 5 . Niobium is reduced from its oxide, fluoride or chloride by aluminum or carbothermy. Particularly pure niobium is obtained by high-temperature reduction of volatile NbCl 5 with hydrogen.
The resulting niobium powder is briquetted and sintered in vacuum in electric arc or electron beam furnaces.
Physical and chemical properties
Niobium is a shiny silver-gray metal with a body-centered cubic crystal lattice of the a-Fe type, A= 0.3294 nm. Melting point 2477°C, boiling point 4760°C, density 8.57 kg/dm3.
Chemically, niobium is quite stable. When calcined in air, it is oxidized to Nb 2 O 5 . About 10 crystal modifications have been described for this oxide. At normal pressure, the b-form of Nb 2 O 5 is stable. When Nb 2 O 5 is alloyed with various oxides, niobates are obtained: Ti 2 Nb 10 O 29, FeNb 49 O 124. Niobates can be considered as salts of hypothetical niobic acids. They are divided into metaniobates MNbO 3, orthoniobates M 3 NbO 4, pyroniobates M 4 Nb 2 O 7 or polyniobates M 2 O n Nb 2 O 5 (M is a singly charged cation, and n= 2-12). Niobates of doubly and triply charged cations are known. Niobates react with HF, melts of alkali metal hydrofluorides (KHF 2) and ammonium (cm. AMMONIUM (in chemistry)). Some niobates with a high M 2 O/Nb 2 O 5 ratio are hydrolyzed:
6Na 3 NbO 4 + 5H 2 O = Na 8 Nb 6 O 19 + 10NaOH
Niobium forms NbO 2, NbO and a number of oxides intermediate between NbO 2.42 and NbO 2.50 and close in structure to the b-form of Nb 2 O 5.
With halogens (cm. HALOGEN) Nb forms pentahalides NbHal 5, tetrahalides NbHal 4 and phases NbHal 2,67 -NbHal 3+x, in which there are Nb 3 or Nb 2 groups. Niobium pentahalides are easily hydrolyzed by water. The melting points of niobium pentachloride, pentabromide and pentaiodide are 205, 267.5 and 310°C. Above 200-250°C these pentahalides are volatile.
In the presence of water vapor and oxygen, NbCl 5 and NbBr 5 form oxyhalides NbOCl 3 (NbOBr 3) - loose cotton wool-like substances.
When Nb and graphite interact, carbides Nb 2 C and NbC, solid heat-resistant compounds, are formed. In the Nb - N system there are several phases of variable composition and nitrides Nb 2 N and NbN. Nb behaves similarly in systems with phosphorus and arsenic. When Nb interacts with sulfur, the following sulfides are obtained: NbS, NbS 2 and NbS 3. Double fluorides Nb and K (Na) - K 2 were synthesized.
Application
50% of the produced niobium is used for microalloying steels, 20-30% for the production of stainless and heat-resistant alloys. Niobium intermetallic compounds (Nb 3 Sn and Nb 3 Ge) are used in the manufacture of solenoids for superconducting devices. Niobium nitride NbN is used in the manufacture of targets for transmitting television tubes. Niobium oxides are components of refractory materials, cermets, and glasses with high refractive indices. Double fluorides - when separating niobium from natural raw materials, during the production of metallic niobium. Niobates are used in acousto- and optoelectronics, as laser materials.
Physiological action
Niobium compounds are poisonous. MPC of niobium in water is 0.01 mg/l.


encyclopedic Dictionary. 2009 .

Synonyms:

See what "niobium" is in other dictionaries:

    - (new Latin niobium). One of the rare metals found in tantalite. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. NIOBium metal, found in the form of oxides in rare minerals, has no practical significance... Dictionary of foreign words of the Russian language

    - (Niobium), Nb, chemical element of group V of the periodic system, atomic number 41, atomic mass 92.9064; metal, melting point 2477 shC. Niobium is used for alloying steels, producing heat-resistant, hard and other alloys. Niobium discovered by English... ... Modern encyclopedia

    Niobium- (Niobium), Nb, chemical element of group V of the periodic system, atomic number 41, atomic mass 92.9064; metal, melting point 2477 °C. Niobium is used for alloying steels, producing heat-resistant, hard and other alloys. Niobium discovered by English... ... Illustrated Encyclopedic Dictionary

    - (symbol Nb), shiny gray-white transition chemical element, metal. Discovered in 1801. It is found, as a rule, in pyrochlore ores. Being a soft and malleable metal, niobium is used in the production of special stainless steels and alloys... ... Scientific and technical encyclopedic dictionary

    Nb (lat. Niobium; from the name Niobe, daughter of Tantalus in other Greek mythology * a. niobium; n. Niob, Niobium; f. niobium; i. niobio), chemical. element of group V is periodic. Mendeleev system, at. n. 41, at. m. 92.9064. It has one natural isotope 93Nb.… … Geological encyclopedia

    NIOBIUM, one of the metals discovered by chemists. Dahl's Explanatory Dictionary. IN AND. Dahl. 1863 1866 … Dahl's Explanatory Dictionary

    NIOBIUM- chem. element, symbol Nb (lat. Niobium), at. n. 41, at. m. 92.90; light gray metal, density 8570 kg/m3, t = 2500 °C; has a high chemical perseverance. In nature, it is found in minerals together with tantalum, separation from which causes... ... Big Polytechnic Encyclopedia

    - (lat. Niobium) Nb, chemical element of group V of the periodic table, atomic number 41, atomic mass 92.9064. Named after Niobe, the daughter of the mythological Tantalus (the similarity of the properties of Nb and Ta). Light gray refractory metal, density 8.57... ... Big Encyclopedic Dictionary

    - (Niobium), Nb, chemical... Physical encyclopedia

    Noun, number of synonyms: 2 metal (86) element (159) ASIS Dictionary of Synonyms. V.N. Trishin. 2013… Synonym dictionary

    - (Niobium French and English, Niob German; chemical), Nb =: 94. in group V of the periodic table of elements there are two rare metals, N. itantalum, which are related to vanadium in the same way as molybdenum and tungsten are to chromium; the last three metal members... ... Encyclopedia of Brockhaus and Efron

It’s worth starting with the fact that niobium is inextricably linked with a substance such as tantalum. This is even despite the fact that these materials were not discovered at the same time.

What is niobium

What is known today about such a substance as niobium? It is a chemical element that is located in group 5 of the periodic table, having an atomic number of 41, as well as an atomic mass of 92.9. Like many other metals, this substance is characterized by a steel-gray luster.

One of the most important physical parameters of this is its refractoriness. It is thanks to this characteristic that the use of niobium has become widespread in many industries. The melting point of this substance is 2468 degrees Celsius, and the boiling point is 4927 degrees Celsius.

The chemical properties of this substance are also at a high level. It is characterized by a high level of resistance to negative temperatures, as well as to most aggressive environments.

Production

It is worth saying that the presence of ore that contains the element Nb (niobium) is much greater than that containing tantalum, but the problem lies in the scarcity of the element itself in this ore.

Most often, in order to obtain this element, a thermal reduction process is carried out, in which aluminum or silicon is involved. As a result of this operation, ferroniobium and ferrotantaloniobium compounds are obtained. It is worth noting that the metallic version of this substance is obtained from the same ore, but more complex technology is used. Niobium crucibles and other resulting materials are characterized by very high performance characteristics.

Methods for obtaining niobium

Currently, some of the most developed directions for obtaining this material are aluminothermic, sodium-thermic and carbothermic. The difference between these types also lies in the precursors that are used to reduce niobium. Let's say K2NbF7 is used in the sodium thermal method. But, for example, in the aluminothermic method, niobium pentoxide is used.

If we talk about the carbothermic method of production, then this technology involves mixing Nb with soot. This process must take place in a high temperature and hydrogen environment. As a result of this operation, niobium carbide will be obtained. The second stage is that the hydrogen environment is replaced by a vacuum, and the temperature is maintained. At this point, its oxide is added to the niobium carbide and the metal itself is obtained.

It is important to note that among the forms of metal produced, niobium in ingots is quite common. This product is intended for the production of metal-based alloys, as well as various other semi-finished products.

A stack of this material can also be produced, which is divided into several categories depending on the purity of the substance. The least amount of impurities is contained in the beaker labeled NBS-00. The NBSh-0 class is characterized by a higher presence of elements such as iron, titanium and tantalum silicon. The category that has the highest impurity indicator is NBS-1. It can be added that niobium in ingots does not have such a classification.

Alternative production methods

Alternative methods include crucibleless electron beam zone melting. This process makes it possible to obtain Nb single crystals. Niobium crucibles are produced using this method. It belongs to powder metallurgy. It is used to first obtain an alloy of this material, and then its pure sample. The presence of this method is the reason why advertisements for the purchase of niobium are quite common. This method allows you to use not the ore itself, which is quite difficult to extract, or a concentrate from it, but secondary raw materials to obtain pure metal.

Another alternative production method is niobium rolling. It is worth noting that most different companies prefer to purchase rods, wire or sheet metal.

Rolled and foil

Foil made from this material is a fairly common semi-finished product. It is the thinnest rolled sheet of this substance. Used for the production of certain products and parts. Niobium foil is obtained from pure raw materials by cold rolling of Nb ingots. The resulting products are characterized by such indicators as high resistance to corrosion, aggressive environments, and high temperatures. Rolled niobium and its ingots also provide such characteristics as wear resistance, high ductility, and good machinability.

Products obtained in this way are most often used in such fields as aircraft manufacturing, rocket science, medicine (surgery), radio engineering, electrical engineering, nuclear energy, and nuclear energy. Niobium foil is packaged in coils and stored in a dry place, protected from moisture, as well as in a place protected from mechanical influence from outside.

Applications in electrodes and alloys

The use of niobium is very widespread. It can be used, like chromium and nickel, as a material that is part of the iron alloy used to make electrodes. Due to the fact that niobium, like tantalum, is capable of forming superhard carbide, it is often used to produce superhard alloys. It can be added that they are currently trying to use this material to improve the properties of alloys obtained on the basis

Since niobium is a raw material capable of creating carbide elements, it, like tantalum, is used as an alloying mixture in the production of steel. It is worth noting that for a long time the use of niobium as an impurity in tantalum was considered a negative effect. However, today the opinion has changed. It was found that Nb can act as a substitute for tantalum, and with great success, since due to its lower atomic mass, smaller amounts of the substance can be used, while maintaining all the old capabilities and effects of the product.

Applications in electrical engineering

It is worth emphasizing that the use of niobium, like its brother tantalum, is possible in rectifiers due to the fact that they have the property of unipolar conductivity, that is, these substances pass electrical current in only one direction. It is possible to use this metal to create devices such as anodes, which are used in powerful generators and amplification tubes.

It is very important to note that the use of niobium has reached nuclear power. In this industry, products made from this substance are used as structural materials. This became possible because the presence of Nb in the parts makes them resistant to heat and also gives them high chemical resistance qualities.

The excellent physical characteristics of this metal have led to its widespread use in rocketry, jet aircraft, and gas turbines.

Niobium production in Russia

If we talk about the reserves of this ore, there are about 16 million tons in total. The largest deposit, occupying approximately 70% of the total volume, is located in Brazil. About 25% of the reserves of this ore are located in Russia. This indicator is considered a significant part of all niobium reserves. The largest deposits of this substance are located in Eastern Siberia, as well as in the Far East. Today, on the territory of the Russian Federation, the Lovozersky GOK company is engaged in the extraction and production of this substance. It can be noted that the Stalmag company was also involved in the production of niobium in Russia. It developed the Tatar deposit of this ore, but was closed in 2010.

You can also add that it is engaged in the production of niobium oxide. They obtain it by processing loparite concentrate. This enterprise produces from 400 to 450 tons of this substance, most of which is exported to countries such as the USA and Germany. Part of the remaining oxide goes to the Chepetsk Mechanical Plant, which produces both pure niobium and its alloys. There are significant capacities there, allowing the production of up to 100 tons of material per year.

Niobium metal and its cost

Despite the fact that the scope of application of this substance is quite wide, its main purpose is the space and nuclear industries. For this reason, Nb is classified as a strategic material.

The main parameters that affect the cost of niobium:

  • purity of the alloy, a large number of impurities reduces the price;
  • form of material delivery;
  • volumes of supplied material;
  • location of the ore receiving point (different regions need different amounts of the element, and therefore the price for it is different).

Approximate list of prices for materials in Moscow:

  • niobium grade NB-2 costs between 420-450 rubles per kg;
  • niobium shavings cost from 500 to 510 rubles per kg;
  • a stick of the NBSh-00 brand costs from 490 to 500 rubles per kg.

It is worth noting that, despite the enormous cost of this product, the demand for it is only increasing.

A chemical element named after the ancient Niobe, a woman who dared to laugh at the gods and paid for it with the death of her children. Niobium represents humanity's transition from industrial to digital production; from steam locomotives to rocket launchers; from coal-fired power plants to nuclear power. The global price of niobium per gram is quite high, as is the demand for it. Most of the latest scientific achievements are closely related to the use of this metal.

Niobium price per gram

Since the main uses of niobium are related to nuclear and space programs, it is classified as a strategic material. Recycling is much more financially profitable than the development and extraction of new ores, which makes niobium in demand in the secondary metal market.

The price for it is determined by several factors:

  • Metal purity. The more foreign impurities, the lower the price.
  • Delivery form.
  • Scope of delivery. Directly proportional to metal prices.
  • Location of the scrap collection point. Each region has a different need for niobium and, accordingly, its price.
  • Presence of rare metals. Alloys containing elements such as tantalum, tungsten, molybdenum are higher in price.
  • The meaning of quotes on world exchanges. These values ​​are the basis for setting prices.

Indicative overview of prices in Moscow:

  • Niobium NB-2. The price varies between 420-450 rubles. per kg.
  • Niobium shavings. 500-510 rub. per kg.
  • Niobium stack NBSh00. Differs in increased prices due to the insignificant content of impurities. 490-500 rub. per kg.
  • Niobium rod NBSh-0. 450-460 rub. per kg.
  • Niobium NB-1 in the form of a rod. The price is 450-480 rubles. per kg.

Despite the high cost, the demand for niobium in the world continues to grow. This happens due to its enormous potential for use and the shortage of metal. There are only 18 grams of niobium per 10 tons of soil.

The scientific community continues to work to find and develop a substitute for such an expensive material. But so far I have not received a concrete result in this. This means that the price of niobium is not expected to fall in the near future.

To regulate prices and increase the speed of turnover, the following categories are provided for niobium products:

  • Niobium ingots. Their size and weight are standardized by GOST 16099-70. Depending on the purity of the metal, they are divided into 3 grades: niobium NB-1, niobium NB-2 and, accordingly, niobium NB-3.
  • Niobium staff. It has a higher percentage of foreign impurities.
  • Niobium foil. Manufactured in thicknesses up to 0.01 mm.
  • Niobium rod. According to TU 48-4-241-73 it is supplied in the grades NbP1 and NbP2.

Physical properties of niobium

The metal is gray with a white tint. Belongs to the group of refractory alloys. The melting point is 2500 ºС. Boiling point 4927 ºС. Differs in the increased value of heat resistance. Does not lose its properties at operating temperatures above 900 ºС.

Mechanical characteristics are also at a high level. The density is 8570 kg/m3, with the same indicator for steel being 7850 kg/m3. Resistant to operation under both dynamic and cyclic loads. Tensile strength - 34.2 kg/mm2. Has high plasticity. The relative elongation coefficient varies between 19-21%, which makes it possible to obtain rolled niobium sheets up to 0.1 mm thick from it.

Hardness is related to the purity of the metal from harmful impurities and increases with their composition. Pure niobium has a Brinell hardness rating of 450.

Niobium lends itself well to pressure treatment at temperatures below -30 ºС and is difficult to cut.

Thermal conductivity does not change significantly with large temperature fluctuations. For example, at 20 ºС it is 51.4 W/(m K), and at 620 ºС it increases by only 4 units. Niobium competes in electrical conductivity with elements such as copper and aluminum. Electrical resistance - 153.2 nOhm m. Belongs to the category of superconducting materials. The temperature at which the alloy enters the superconductor mode is 9.171 K.

Extremely resistant to acidic environments. Such common acids as sulfuric, hydrochloric, orthophosphoric, nitric do not affect its chemical structure in any way.

At temperatures above 250 ºС, niobium begins to be actively oxidized by oxygen, and also enter into chemical reactions with hydrogen and nitrogen molecules. These processes increase the fragility of the metal, thereby reducing its strength.

  • Does not apply to allergenic materials. Introduced into the human body, it does not cause a rejection reaction by the body.
  • It is a metal of the first group of weldability. The welds are tight and do not require preparatory operations. Resistant to cracking.

Types of alloys

Based on the value of mechanical properties at elevated temperatures, niobium alloys are divided into:

  1. Low strength. They operate within the range of 1100-1150 ºС. They have a simple set of alloying elements. This mainly includes zirconium, titanium, tantalum, vanadium, hafnium. Strength is 18-24 kg/mm2. After passing the critical temperature threshold, it drops sharply and becomes similar to pure niobium. The main advantage is high plastic properties at temperatures up to 30 ºС and good workability under pressure.
  2. Medium strength. Their operating temperature is in the range of 1200-1250 ºС. In addition to the above alloying elements, they contain impurities of tungsten, molybdenum, and tantalum. The main purpose of these additives is to preserve mechanical properties with increasing temperature. They have moderate ductility and can be easily processed under pressure. A striking example of an alloy is niobium 5VMC.
  3. High strength alloys. Used at temperatures up to 1300 ºС. With short-term exposure up to 1500 ºС. They differ in their chemical composition of higher complexity. 25% consist of additives, the main share of which is tungsten and molybdenum. Some types of these alloys are characterized by a high carbon content, which has a positive effect on their heat resistance. The main disadvantage of high-strength niobium is low ductility, which makes processing difficult. And, accordingly, obtaining industrial semi-finished products.

It should be noted that the categories listed above are of a conditional nature and give only a general idea of ​​​​the method of using a particular alloy.

Also worth mentioning are compounds such as ferroniobium and niobium oxide.

Ferroniobium is a compound of niobium with iron, where the content of the latter is at the level of 50%. In addition to the main elements, it includes hundredths of titanium, sulfur, phosphorus, silicon, and carbon. The exact percentage of elements is standardized by GOST 16773-2003.

Niobium pentaxide is a white crystalline powder. Not susceptible to dissolution in acid and water. It is produced by burning niobium in an oxygen environment. Completely amorphous. Melting point 1500 ºС.

Applications of niobium

All of the above properties make the metal extremely popular in various industries. Among the many ways to use it, the following positions are distinguished:

  • Used in metallurgy as an alloying element. Moreover, both ferrous and non-ferrous alloys are alloyed with niobium. For example, adding just 0.02% of it to stainless steel 12Х18Н10Т increases its wear resistance by 50%. Aluminum improved with niobium (0.04%) becomes completely impervious to alkali. Niobium acts on copper as a hardening agent on steel, increasing its mechanical properties by an order of magnitude. Note that even uranium is doped with niobium.
  • Niobium pentoxide is the main component in the manufacture of highly refractory ceramics. It has also found application in the defense industry: armored glass of military equipment, optics with a large refractive angle, etc.
  • Ferroniobium is used to alloy steels. Its main task is to increase corrosion resistance.
  • In electrical engineering they are used for the manufacture of capacitors and current rectifiers. Such capacitors are characterized by increased capacitance and insulation resistance, and small sizes.
  • Compounds of silicon and germanium with niobium are widely used in the field of electronics. Superconducting solenoids and elements of current generators are made from them.

    • Application of niobium for metal alloying

    Niobium alloyed steel has good corrosion resistance. Chromium also increases the corrosion resistance of steel, and it is much cheaper than niobium. This reader is right and wrong at the same time. I’m wrong because I forgot about one thing.

    Chromium-nickel steel, like any other, always contains carbon. But carbon combines with chromium to form carbide, which makes the steel more brittle. Niobium has a greater affinity for carbon than chromium. Therefore, when niobium is added to steel, niobium carbide is necessarily formed. Steel alloyed with niobium acquires high anti-corrosion properties and does not lose its ductility. The desired effect is achieved when only 200 g of niobium metal is added to a ton of steel. And niobium imparts high wear resistance to chrome-manganese steel.

    Many non-ferrous metals are also alloyed with niobium. Thus, aluminum, which easily dissolves in alkalis, does not react with them if only 0.05% niobium is added to it. And copper, known for its softness, and many of its alloys seem to be hardened by niobium. It increases the strength of metals such as titanium, molybdenum, zirconium, and at the same time increases their heat resistance and heat resistance.

    Now the properties and capabilities of niobium are appreciated by aviation, mechanical engineering, radio engineering, the chemical industry, and nuclear energy. All of them became consumers of niobium.

    The unique property - the absence of noticeable interaction of niobium with uranium at temperatures up to 1100°C and, in addition, good thermal conductivity, a small effective absorption cross section of thermal neutrons - made niobium a serious competitor to metals recognized in the nuclear industry - aluminum, beryllium and zirconium. In addition, the artificial (induced) radioactivity of niobium is low. Therefore, it can be used to make containers for storing radioactive waste or installations for their use.

    The chemical industry consumes relatively little niobium, but this can only be explained by its scarcity. Equipment for the production of high-purity acids is sometimes made from niobium-containing alloys and, less commonly, from sheet niobium. Niobium's ability to influence the rate of certain chemical reactions is used, for example, in the synthesis of alcohol from butadiene.

    Rocket and space technology also became consumers of element No. 41. It is no secret that some quantities of this element are already rotating in near-Earth orbits. Some parts of rockets and on-board equipment of artificial Earth satellites are made from niobium-containing alloys and pure niobium.

    Uses of niobium in other industries

    “Hot fittings” (i.e. heated parts) are made from niobium sheets and bars - anodes, grids, indirectly heated cathodes and other parts of electronic lamps, especially powerful generator lamps.

    In addition to pure metal, tantalonium-bium alloys are used for the same purposes.

    Niobium was used to make electrolytic capacitors and current rectifiers. Here, the ability of niobium to form a stable oxide film during anodic oxidation is used. The oxide film is stable in acidic electrolytes and passes current only in the direction from the electrolyte to the metal. Niobium capacitors with solid electrolyte are characterized by high capacity with small dimensions and high insulation resistance.

    Niobium capacitor elements are made from thin foil or porous plates pressed from metal powders.

    The corrosion resistance of niobium in acids and other media, combined with high thermal conductivity and ductility, make it a valuable structural material for equipment in chemical and metallurgical industries. Niobium has a combination of properties that meet the requirements of nuclear energy for structural materials.

    Up to 900°C, niobium weakly interacts with uranium and is suitable for the manufacture of protective shells for uranium fuel elements of power reactors. In this case, it is possible to use liquid metal coolants: sodium or an alloy of sodium and potassium, with which niobium does not interact up to 600°C. To increase the survivability of uranium fuel elements, uranium is doped with niobium (~ 7% niobium). The niobium additive stabilizes the protective oxide film on uranium, which increases its resistance to water vapor.

    Niobium is a component of various heat-resistant alloys for jet engine gas turbines. Alloying molybdenum, titanium, zirconium, aluminum and copper with niobium dramatically improves the properties of these metals, as well as their alloys. There are heat-resistant alloys based on niobium as a structural material for parts of jet engines and rockets (manufacture of turbine blades, leading edges of wings, nose ends of aircraft and rockets, rocket skins). Niobium and alloys based on it can be used at operating temperatures of 1000 - 1200°C.

    Niobium carbide is a component of some grades of tungsten carbide-based carbide used for cutting steels.

    Niobium is widely used as an alloying additive in steels. The addition of niobium in an amount 6 to 10 times higher than the carbon content in steel eliminates intergranular corrosion of stainless steel and protects welds from destruction.

    Niobium is also added to various heat-resistant steels (for example, for gas turbines), as well as to tool and magnetic steels.

    Niobium is introduced into steel in an alloy with iron (ferroniobium), containing up to 60% Nb. In addition, ferrotantaloniobium is used with different ratios between tantalum and niobium in the ferroalloy.

    In organic synthesis, some niobium compounds (fluoride complex salts, oxides) are used as catalysts.

    The use and production of niobium are rapidly increasing, which is due to a combination of such properties as refractoriness, a small cross section for thermal neutron capture, the ability to form heat-resistant, superconducting and other alloys, corrosion resistance, getter properties, low electron work function, good workability under cold pressure and weldability. The main areas of application of niobium are: rocketry, aviation and space technology, radio engineering, electronics, chemical engineering, nuclear energy.

    Applications of metallic niobium
    • Aircraft parts are made from pure niobium or its alloys; claddings for uranium and plutonium fuel elements; containers and pipes; for liquid metals; parts of electrolytic capacitors; “hot” fittings for electronic (for radar installations) and powerful generator lamps (anodes, cathodes, grids, etc.); corrosion-resistant equipment in the chemical industry.
    • Other non-ferrous metals, including uranium, are alloyed with niobium.
    • Niobium is used in cryotrons - superconducting elements of computers. Niobium is also known for its use in the accelerating structures of the Large Hadron Collider.
    Intermetallic compounds and alloys of niobium
    • Nb 3 Sn stannide and alloys of niobium with titanium and zirconium are used for the manufacture of superconducting solenoids.
    • Niobium and alloys with tantalum in many cases replace tantalum, which gives a great economic effect (niobium is cheaper and almost twice as light as tantalum).
    • Ferroniobium is introduced into stainless chromium-nickel steels to prevent their intergranular corrosion and destruction and into other types of steel to improve their properties.
    • Niobium is used in the minting of collectible coins. Thus, the Bank of Latvia claims that niobium is used along with silver in 1 lat collection coins.
    Application of niobium compounds
    • Nb 2 O 5 catalyst in the chemical industry;
    • in the production of refractories, cermets, specials. glass, nitride, carbide, niobates.
    • Niobium carbide (mp 3480 °C) alloyed with zirconium carbide and uranium-235 carbide is the most important structural material for fuel rods of solid-phase nuclear jet engines.
    • Niobium nitride NbN is used to produce thin and ultra-thin superconducting films with a critical temperature of 5 to 10 K with a narrow transition of the order of 0.1 K
    Niobium in medicine

    The high corrosion resistance of niobium has made it possible to use it in medicine. Niobium threads do not cause irritation to living tissue and adhere well to it. Reconstructive surgery has successfully used such threads to stitch together torn tendons, blood vessels and even nerves.

    Application in jewelry

    Niobium not only has a set of properties necessary for technology, but also looks quite beautiful. Jewelers tried to use this white shiny metal to make watch cases. Alloys of niobium with tungsten or rhenium sometimes replace noble metals: gold, platinum, iridium. The latter is especially important, since the niobium-rhenium alloy not only looks similar to the metallic iridium, but is almost as wear-resistant. This allowed some countries to do without expensive iridium in the production of soldering tips for fountain pen nibs.

    Niobium as a first generation superconducting material

    The amazing phenomenon of superconductivity, when when the temperature of a conductor decreases, an abrupt disappearance of electrical resistance occurs in it, was first observed by the Dutch physicist G. Kamerlingh-Onnes in 1911. The first superconductor turned out to be mercury, but not it, but niobium and some intermetallic compounds of niobium were destined to become the first technically important superconducting materials.

    Two characteristics of superconductors are practically important: the value of the critical temperature at which the transition to the state of superconductivity occurs, and the critical magnetic field (Kamerlingh Onnes also observed the loss of superconductivity by a superconductor when exposed to a sufficiently strong magnetic field). In 1975, the intermetallic compound of niobium and germanium with the composition Nb 3 Ge became the record holder for the highest critical temperature. Its critical temperature is 23.2°K; This is higher than the boiling point of hydrogen. (Most known superconductors become superconductors only at the temperature of liquid helium).

    The ability to transition to a state of superconductivity is also characteristic of niobium stannide Nb 3 Sn, alloys of niobium with aluminum and germanium or with titanium and zirconium. All these alloys and compounds are already used to make superconducting solenoids, as well as some other important technical devices.

    • One of the actively used superconductors (superconducting transition temperature 9.25 K). Niobium compounds have a superconducting transition temperature of up to 23.2 K (Nb 3 Ge).
    • The most commonly used industrial superconductors are NbTi and Nb 3 Sn.
    • Niobium is also used in magnetic alloys.
    • Used as an alloying additive.
    • Niobium nitride is used to produce superconducting bolometers.

    The exceptional resistance of niobium and its alloys with tantalum in superheated cesium-133 vapor makes it one of the most preferred and cheapest structural materials for high-power thermionic generators.