Niobium is a chemical element with atomic number 41 and chemical symbol Nb (formerly columbium, Cb). It is a light gray, crystalline, ductile transition metal. Pure niobium is comparable to pure titanium in terms of Mohs hardness and is ductile to iron. Niobium is used in jewelry as a hypoallergenic substitute for nickel, as it oxidizes relatively slowly in Earth's atmosphere. The old name "columbium" comes from the frequent presence of niobium in the pyrochlore and columbite minerals. Niobe, the daughter of Tantalus and the source of tantalum's name, originated in Greek mythology. The name refers to how difficult it is to distinguish the two elements due to their extreme physical and chemical similarities.
Columbium is a new element that was discovered by the English chemist Charles Hatchett in 1801 and is comparable to tantalum. British scientist William Hyde Wollaston incorrectly claimed in 1809 that tantalum and columbium could be used interchangeably. German chemist Heinrich Rose discovered the presence of the second element, niobium, in tantalum ores in 1846. Scientific discoveries made in 1864 and 1865 made it clear that niobium and columbium were the same element (as opposed to tantalum), and for a century both names were used as synonyms. Although the name columbium is still used in American metallurgy today, niobium was officially adopted as the element's name in 1949.
Niobium was not first used commercially until the early 20th century. It is very important to add niobium to high strength low alloy steels. Ferroniobium, an alloy of niobium and 60 to 70 percent niobium and iron, is mostly produced in Brazil. Most of the niobium is used in alloys, mostly in special steels used in products such as gas pipelines. Despite having a maximum niobium content of 0,1%, these alloys increase the strength of steel by removing carbide and nitride. Niobium-containing superalloys must be resistant to temperature in order to be used in jet and rocket engines.
Many superconducting materials contain niobium. These alloys, which also contain titanium and tin, are frequently used in the superconducting magnets of MRI scanners. Niobium is also used in welding, nuclear industry, electronics, optics, jewellery, numismatics and other fields. The low toxicity and iridescence produced by anodization are highly desirable qualities in the last two applications. Niobium is recognized as a very important component of technology.
History of the Element Niobium
British chemist Charles Hatchett first recognized niobium in 1801. In 1734, John Winthrop FRS, grandson of Young John Winthrop, sent a mineral sample from the United States state of Connecticut to England. This sample contained a new element discovered by him. He named the mineral columbite and the new element columbium after the country's poetic name, Columbia.
Hatchett's discovery of columbium was likely a combination of tantalum and the newly found element.
Later there was a lot of misunderstanding about the distinction between columbium (niobium) and tantalum, which is very similar. Derived from columbium and having a density of 5,918 g/cm3 derived from columbite and tantalum with a density of 8 g/cm3Tantalite, which is above , was compared in 1809 by the English chemist William Hyde Wollaston. He found that despite the significantly different densities of the two oxides, they were the same, hence retaining the name tantalum.
The German chemist Heinrich Rose disputed this conclusion in 1846 and claimed that the tantalite sample contained two different elements, which he named niobium (from Niobe) and pelopium (from Pelops), after Tantalus' offspring. The small differences observed between tantalum and niobium caused this error. In fact, the so-called new elements pelopium, ilmenium, and dianium are different forms of tantalum or niobium, respectively.
Christian Wilhelm Blomstrand and Henri Étienne Sainte-Claire Deville proved in 1864 that there are only two elements in tantalum and niobium. In 1865, Louis J. Troost determined the formulas of some compounds. Finally, the Swiss chemist Jean Charles Galissard de Marignac proved this in 1866. Articles on ilmenium continued to appear until 1871.
Use of Niobium Element
Niobium chloride was reduced by heating in hydrogen environment by De Marignac in 1864 and was the first preparation of this metal. Although de Marignac succeeded in synthesizing tantalum-free niobium on a larger scale in 1866, niobium was first used commercially in incandescent lamp filaments in the early 20th century.
Niobium was quickly replaced by tungsten, which had a higher melting point, and this use became obsolete. The ability of niobium to strengthen steel was first identified in the 1920s, and this use is still its primary use today. The discovery that niobium tin maintains its superconductivity in the presence of strong electric currents and magnetic fields was made in 1961 by the American physicist Eugene Kunzler and his colleagues at Bell Labs. This made niobium tin the first material to support the high currents and fields required for useful high-power magnets and electrical machines. Twenty years after this discovery, long stranded wires twisted into coils could be produced, allowing the creation of enormous, powerful electromagnets for spinning machines, particle accelerators, and particle detectors.
Physical Properties of Niobium Element
Niobium, a group 5 metal of the periodic table, is a shiny, gray, ductile, paramagnetic metal (see table) with an unusual electron configuration in its outermost shell. Ruthenium, rhodium, and palladium are found nearby and exhibit similar unusual structures.
It is believed to have a body-centered cubic crystal structure from absolute zero to its melting point, but high-resolution measurements of thermal expansion along the three crystallographic axes show anisotropies incompatible with a cubic structure. As a result, further research and exploration in this area is expected.
Cryogenic temperatures cause niobium to transform into a superconductor. Its critical temperature of 9,2 K at atmospheric pressure makes it the most critical of elemental superconductors. Of all the elements, niobium has the deepest magnetic penetration. Along with vanadium and technetium, it is one of the three primary Type II superconductors. The purity of niobium metal has a significant effect on its superconducting qualities.
It is quite soft and ductile when fairly pure, but impurities cause it to be harder.
Because the metal has a low thermal neurotrapping cross section, it is used in the nuclear industry to create neutron transparent structures.
Chemical Structure of Niobium Element
When the metal is left in air at room temperature for a long time, it takes on a bluish color. The basic form of this metal has a high melting point (2,468 °C), but is less dense than other refractory metals. It also forms dielectric oxide layers, shows superconductivity and is corrosion resistant.
Due to lanthanide shrinkage, niobium is nearly equal in size to the heavier tantalum atoms, whereas its predecessor in the periodic table, zirconium, is slightly less electropositive and more compact. As a result, niobium is chemically very similar to tantalum, which is located just below niobium on the periodic table. Although niobium is not as outstanding in corrosion resistance as tantalum, it is attractive for less demanding applications such as boiler coatings in chemical plants due to its lower price and higher availability.
Source: Wikipedia
📩 29/04/2023 16:20