Titanium
Titanium (lat. titanium) is a chemical element in the Periodic Table of Elements, which has the symbol Ti and proton number 22. It is a light, strong, shiny transition metal with a steel appearance, resistant to corrosion (also in seawater, acids, or in presence of chlorine). In nature, titanium occurs only in the form of compounds, the most widespread minerals are rutile and ilmenite.
Titanium is used as a component of hard and light alloys (with iron, aluminum, vanadium, molybdenum and many other elements), which have wide application in many branches of industry (in cosmonautics, military, aviation, mechanical engineering, chemical industry, medicine, etc.) . Titanium dioxide is used as a white pigment (under the name titanium white), also as a component of toothpastes and as a photocatalyst.
History
Titanium was first identified as a new element by the amateur geologist William Gregor (pastor by profession and later vicar of the parish of Creed in Cornwall) in 1791, who noticed that black sand from the alluvium in the neighboring village of Manaccan was attracted by a magnet. This sand was the mineral ilmenite, and by analyzing it, Gregor discovered that it is made up of two oxides - iron and a new, until then unidentified element (titanium dioxide). He announced his discovery to the Royal Geological Society of Cornwall (Royal Geological Society of Cornwall) and also published it in the German scientific journal Creel's Annalen.
Around the same time, Hungarian mineralogist Franz-Joseph Müller von Reichenstein prepared the same compound, but was unable to identify it. Titanium dioxide was rediscovered in 1795 by the German chemist Martin Heinrich Klaproth in rutile from Hungary (more precisely from the site near Revúca on the territory of today's Slovakia), who also proved that it is the oxide of a new element and named this element Titans after the giants from Greek mythology. Learning of Gregor's earlier discovery, he confirmed that the same element was also found in the black sands of Manaccan.
However, the actual production of pure titanium was achieved only in 1910 by Matthew Hunter, who prepared the metal with a purity of 99.9% by reducing titanium chloride with sodium at a temperature of 700 to 800 °C. Because titanium reacts with carbon at elevated temperatures, so the classic methods of reducing ores with coke failed. However, sodium reduction was very expensive and the amount of titanium produced by this process was just enough for laboratory experiments. It wasn't until 1932 that Luxembourg metallurgist William Kroll replaced sodium with calcium, and nine years later with magnesium, and titanium began to be produced industrially. Kroll's process is still used to produce titanium today, despite the fact that there are also cheaper methods of preparation
Chemical properties
The most important property of titanium is its resistance to corrosion, as well as its insolubility in most dilute acid solutions, although it dissolves in concentrated acids. With an E° value of −0.42 V, it should displace hydrogen from water, but this reaction practically does not take place. A passivation layer of titanium dioxide is formed on the surface, which prevents further corrosion.
At elevated temperatures in the air, a passivation and protective oxide layer is formed on titanium, preventing corrosion, but at room temperature it resists corrosion. If heated to 610°C or higher in air, it burns to form titanium dioxide; and is one of the few elements that burns even in a pure nitrogen atmosphere (burns at 800 °C). Titanium resists dilute sulfuric acid and hydrochloric acid, as well as chlorine gas and most organic acids.
Experiments have shown that natural titanium turns radioactive when bombarded with deuterons, emitting mainly positrons and hard gamma rays. Red-hot, it combines with oxygen, and at a temperature of 550 °C it also combines with chlorine. It also reacts with other halogens and absorbs hydrogen.
The use
The practical use of elemental titanium results primarily from its extraordinary chemical resistance and low density. It should be taken into account that the production of titanium is currently relatively financially demanding, and the operational deployment of titanium components is expedient only in cases where it is not possible to use a cheaper alternative based on aluminum and magnesium alloys - durals.
From the beginning of the industrial production of titanium metal, the focus of its use was in space technologies and special applications of the aviation industry. Titanium and its alloys are therefore the basic material in the production of skeletons or surface protective shields of space objects (satellites, space probes and space stations). In the aviation industry, they find use in the production of significantly stressed aircraft components, i.e. primarily in the construction of military fighter aircraft and today also in the construction of commercial transport aircraft.
In the chemical industry, titanium is an increasingly popular material for the production or simple lining of chemical reactors that operate in extreme conditions and require high corrosion resistance.
Titanium is increasingly used in devices that work in contact with seawater for a long time. They can be parts of ships or submarines (ship propellers), but also components of industrial units used for desalination (desalination) of seawater.
In ordinary everyday life, we can meet with titan, e.g. as with material for the production of luxury wristwatches or jewelry parts.
