Product Code Database
Niobium is a chemical element; it has chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, (1968). 9781468460667, IFI-Plenum. ISBN 9781468460667 and it has similar ductility to iron. Niobium oxidizes in Earth's atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel. Niobium is often found in the minerals pyrochlore and columbite. Its name comes from Greek mythology: Niobe, daughter of Tantalus, the namesake of tantalum. The name reflects the great similarity between the two elements in their physical and chemical properties, which makes them difficult to distinguish.Knapp, Brian (2002). Francium to Polonium. Atlantic Europe Publishing Company, p. 40. .
English chemist Charles Hatchett reported a new element similar to tantalum in 1801 and named it columbium. In 1809, English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. Niobium was officially adopted as the name of the element in 1949, but the name columbium remains in current use in metallurgy in the United States.
It was not until the early 20th century that niobium was first used commercially. Niobium is an important addition to high-strength low-alloy steels. Brazil is the leading producer of niobium and ferroniobium, an alloy of 60–70% niobium with iron. Niobium is used mostly in alloys, the largest part in special steel such as that used in gas pipelines. Although these alloys contain a maximum of 0.1%, the small percentage of niobium enhances the strength of the steel by scavenging carbide and nitride. The temperature stability of niobium-containing is important for its use in jet engine and .
Niobium is used in various superconducting materials. These alloys, also containing titanium and tin, are widely used in the superconducting magnets of MRI scanners. Other applications of niobium include welding, nuclear industries, electronics, optics, numismatics, and jewelry. In the last two applications, the low toxicity and iridescence produced by anodization are highly desired properties.
Subsequently, there was considerable confusion over the difference between columbium (niobium) and the closely related tantalum. In 1809, English chemist William Hyde Wollaston compared the oxides derived from both columbium—columbite, with a density 5.918 g/cm, and tantalum—tantalite, with a density over 8 g/cm, and concluded that the two oxides, despite the significant difference in density, were identical; thus he kept the name tantalum. This conclusion was disputed in 1846 by German chemist Heinrich Rose, who argued that there were two different elements in the tantalite sample, and named them after children of Tantalus: niobium (from Niobe) and pelopium (from Pelops). This confusion arose from the minimal observed differences between tantalum and niobium. The claimed new elements pelopium, ilmenium, and dianium were in fact identical to niobium or mixtures of niobium and tantalum.
The differences between tantalum and niobium were unequivocally demonstrated in 1864 by Christian Wilhelm Blomstrand and Henri Étienne Sainte-Claire Deville, as well as Louis J. Troost, who determined the formulas of some of the compounds in 1865 and finally by Swiss chemist Jean Charles Galissard de Marignac in 1866, who all proved that there were only two elements. Articles on ilmenium continued to appear until 1871.
Christian Wilhelm Blomstrand was the first to prepare the metal in 1866, when he redox niobium chloride by heating it in an atmosphere of hydrogen. Although de Marignac was able to produce tantalum-free niobium on a larger scale by 1866, it was not until the early 20th century that niobium was used in incandescent lamp filaments, the first commercial application. This use quickly became obsolete through the replacement of niobium with tungsten, which has a higher melting point. That niobium improves the strength of steel was first discovered in the 1920s, and this application remains its predominant use. In 1961, the American physicist Eugene Kunzler and coworkers at Bell Labs discovered that niobium–tin continues to exhibit superconductivity in the presence of strong electric currents and magnetic fields,Geballe et al. (1993) gives a critical point at currents of 150 kilo and magnetic fields of 8.8 tesla. making it the first material to support the high currents and fields necessary for useful high-power magnets and electrical power machinery. This discovery enabled—two decades later—the production of long multi-strand cables wound into coils to create large, powerful for rotating machinery, particle accelerators, and particle detectors.
| 2, 8, 11, 2 |
| 2, 8, 18, 12, 1 |
| 2, 8, 18, 32, 11, 2 |
| 2, 8, 18, 32, 32, 11, 2 |
Although it is thought to have a body-centered cubic crystal structure from absolute zero to its melting point, high-resolution measurements of the thermal expansion along the three crystallographic axes reveal anisotropies which are inconsistent with a cubic structure. Therefore, further research and discovery in this area is expected.
Niobium becomes a superconductor at cryogenics temperatures. At atmospheric pressure, it has the highest critical temperature of the elemental superconductors at 9.2 Kelvin. Niobium has the greatest magnetic penetration depth of any element. In addition, it is one of the three elemental Type II superconductors, along with vanadium and technetium. The superconductive properties are strongly dependent on the purity of the niobium metal.
When very pure, it is comparatively soft and ductile, but impurities make it harder.
The metal has a low capture cross-section for thermal ; thus it is used in the nuclear industries where neutron transparent structures are desired.
Niobium is slightly less electropositive and more compact than its predecessor in the periodic table, zirconium, whereas it is virtually identical in size to the heavier tantalum atoms, as a result of the lanthanide contraction. As a result, niobium's chemical properties are very similar to those for tantalum, which appears directly below niobium in the periodic table. Although its corrosion resistance is not as outstanding as that of tantalum, the lower price and greater availability make niobium attractive for less demanding applications, such as vat linings in chemical plants.
The most stable of isomeric state of a niobium isotope is Nb with half-life 16.12 years. The long-lived fission product 93Zr decays, mainly through this isomer, to stable niobium.
The three largest currently mined deposits of pyrochlore, two in Brazil and one in Canada, were found in the 1950s, and are still the major producers of niobium mineral concentrates. The largest deposit is hosted within a carbonatite intrusion in Araxá, state of Minas Gerais, Brazil, owned by CBMM (Companhia Brasileira de Metalurgia e Mineração); the other active Brazilian deposit is located near Catalão, state of Goiás, and owned by China Molybdenum, also hosted within a carbonatite intrusion. Together, those two mines produce about 88% of the world's supply. Brazil also has a large but still unexploited deposit near São Gabriel da Cachoeira, state of Amazonas, as well as a few smaller deposits, notably in the state of Roraima.
The third largest producer of niobium is the carbonatite-hosted Niobec mine, in Saint-Honoré, near Chicoutimi, Quebec, Canada, owned by Magris Resources. It produces between 7% and 10% of the world's supply.
The first industrial scale separation, developed by Switzerland chemist de Marignac, exploits the differing Solubility of the complex niobium and tantalum , dipotassium oxypentafluoroniobate monohydrate () and dipotassium heptafluorotantalate () in water. Newer processes use the liquid extraction of the fluorides from aqueous solution by organic solvents like cyclohexanone. The complex niobium and tantalum fluorides are extracted separately from the organic solvent with water and either precipitated by the addition of potassium fluoride to produce a potassium fluoride complex, or precipitated with ammonia as the pentoxide:
Followed by:
Several methods are used for the reduction to metallic niobium. The electrolysis of a Molten salt of and sodium chloride is one; the other is the reduction of the fluoride with sodium. With this method, a relatively high purity niobium can be obtained. In large scale production, is reduced with hydrogen or carbon. In the aluminothermic reaction, a mixture of iron oxide and niobium oxide is reacted with aluminium:
Small amounts of oxidizers like sodium nitrate are added to enhance the reaction. The result is aluminium oxide and ferroniobium, an alloy of iron and niobium used in steel production. Ferroniobium contains between 60 and 70% niobium. Without iron oxide, the aluminothermic process is used to produce niobium. Further purification is necessary to reach the grade for superconductive alloys. Electron beam melting under vacuum is the method used by the two major distributors of niobium.
, CBMM from Brazil controlled 85 percent of the world's niobium production. The United States Geological Survey estimates that the production increased from 38,700 tonnes in 2005 to 44,500 tonnes in 2006. Worldwide resources are estimated to be 4.4 million tonnes. During the ten-year period between 1995 and 2005, the production more than doubled, starting from 17,800 tonnes in 1995. Between 2009 and 2011, production was stable at 63,000 tonnes per year, Niobium (Colombium) U.S. Geological Survey, Mineral Commodity Summaries, January 2011 with a slight decrease in 2012 to only 50,000 tonnes per year. Niobium (Colombium) U.S. Geological Survey, Mineral Commodity Summaries, January 2016
| + Mine production (t) (USGS estimate) |
| 59,800 |
| 6,500 |
| ? |
| ? |
| ? |
| ? |
| ? |
| 67,700 |
Lesser amounts are found in Malawi's Kanyika Deposit (Kanyika mine).
Although niobium exhibits all of the formal oxidation states from +5 to −1, the most common compounds have niobium in the +5 state. Characteristically, compounds in oxidation states less than 5+ display Nb–Nb bonding. In aqueous solutions, niobium only exhibits the +5 oxidation state. It is also readily prone to hydrolysis and is barely soluble in dilute solutions of hydrochloric, sulfuric acid, nitric acid and due to the precipitation of hydrous Nb oxide. Nb(V) is also slightly soluble in alkaline media due to the formation of soluble polyoxoniobate species.
Materials can be coated with a thin film of niobium(V) oxide chemical vapor deposition or atomic layer deposition processes, produced by the thermal decomposition of niobium(V) ethoxide above 350 °C.
Anionic halide compounds of niobium are well known, owing in part to the of the pentahalides. The most important is NbF72−, an intermediate in the separation of Nb and Ta from the ores. This heptafluoride tends to form the oxopentafluoride more readily than does the tantalum compound. Other halide complexes include octahedral :
As with other metals with low atomic numbers, a variety of reduced halide cluster ions is known, the prime example being .
These same niobium alloys are often used in pipeline construction.
One example superalloy is inconel, consisting of roughly 50% nickel, 18.6% chromium, 18.5% iron, 5% niobium, 3.1% molybdenum, 0.9% titanium, and 0.4% aluminium.
These superalloys were used, for example, in advanced air frame systems for the Gemini program. Another niobium alloy was used for the nozzle of the Apollo Service Module. Because niobium is oxidized at temperatures above 400 °C, a protective coating is necessary for these applications to prevent the alloy from becoming Brittleness.
The reactivity of niobium with oxygen requires it to be worked in a Outgassing or Inert gas, which significantly increases the cost and difficulty of production. Vacuum arc remelting (VAR) and electron beam melting (EBM), novel processes at the time, enabled the development of niobium and other reactive metals. The project that yielded C-103 began in 1959 with as many as 256 experimental niobium alloys in the "C-series" (C arising possibly from columbium) that could be melted as buttons and rolled into Sheet metal. Wah Chang Corporation had an inventory of hafnium, refined from nuclear-grade , that it wanted to put to commercial use. The 103rd experimental composition of the C-series alloys, Nb-10Hf-1Ti, had the best combination of formability and high-temperature properties. Wah Chang fabricated the first 500 lb heat of C-103 in 1961, ingot to sheet, using EBM and VAR. The intended applications included Gas turbine and liquid metal . Competing niobium alloys from that era included FS85 (Nb-10W-28Ta-1Zr) from Fansteel., Cb129Y (Nb-10W-10Hf-0.2Y) from Wah Chang and Boeing, Cb752 (Nb-10W-2.5Zr) from Union Carbide, and Nb1Zr from Superior Tube Co.
The nozzle of the Merlin Vacuum series of engines developed by SpaceX for the upper stage of its Falcon 9 rocket is made from a C-103 niobium alloy.
Niobium-based superalloys are used to produce components to hypersonic missile systems.
The high sensitivity of superconducting niobium nitride make them an ideal detector for electromagnetic radiation in the THz frequency band. These detectors were tested at the Submillimeter Telescope, the South Pole Telescope, the Receiver Lab Telescope, and at APEX, and are now used in the HIFI instrument on board the Herschel Space Observatory.
Like titanium, tantalum, and aluminium, niobium can be heated and ("reactive metal anodizing") to produce a wide array of Iridescence colours for jewelry, where its hypoallergenic property is highly desirable.
Niobium is used in arc welding rods for some stabilized grades of stainless steel and in anodes for cathodic protection systems on some water tanks, which are then usually plated with platinum.
Niobium is used to make the high voltage wire of the solar corona particles receptor module of the Parker Solar Probe.
Niobium is a constituent of a lightfast chemically stable inorganic yellow pigment that has the trade name NTP Yellow. It is Niobium Sulfur Tin Zinc Oxide, a pyrochlore, produced via high-temperature calcination. The pigment is also known as pigment yellow 227, commonly listed as PY 227 or PY227.
Niobium is employed in the atomic energy industry for its high temperature and corrosion resistance, as well as its stability under radiation. It is used in nuclear reactors for components like fuel rods and reactor cores.
Nickel niobium alloys are used in aerospace, oil and gas, construction. They are used in components of jet engines, in ground gas turbines, elements of bridges and high-rise buildings.
Short- and long-term exposure to niobates and niobium chloride, two water-soluble chemicals, have been tested in rats. Rats treated with a single injection of niobium pentachloride or niobates show a median lethal dose (LD) between 10 and 100 mg/kg. For oral administration the toxicity is lower; a study with rats yielded a LD after seven days of 940 mg/kg.
|
|
