Titanium is considered a common chemical element, its concentration in the earth's crust is about 0.57% by weight.Among the structural metals from the ranks fourth in prevalence concede aluminum, iron and magnesium.In free form, the metal does not occur.Most of the titanium contained in the main basalt rocks shell, least of all - in ultrabasic rocks.
among the rocks, enriched with titanium, the best known syenite and pegmatite.There are more than 100 titanium minerals, mainly of magmatic origin, the most important of them: rutile and rarer crystalline modifications - anatase and brookite, sphene, titanomagnetite, ilmenite and perovskite.In the biosphere, titanium dispersed, this chemical element is considered slightly migratory.
Titanium exists in two allotropic modifications: below 8
82 ° C it is stable shape with a hexagonal close-packed lattice, above this temperature - with a body-centered cubic.
technical titanium, which is used in industry, contains impurities of nitrogen, oxygen, iron, carbon and silicon, reducing its flexibility and increase strength.
Pure titanium - reactive transition element in the compounds it is the oxidation state of 4, 2, and 3 less.Due to the presence on the surface of the metal thin and strong oxide film is resistant to corrosion at temperatures up to 500-550 ° C with oxygen the metal begins to react at a temperature significantly above 600 ° C.
During mechanical work fine titanium chips can ignite if the environment sufficient concentration of oxygen and oxide film damaged by impact or friction.Perhaps sunbathing titanium at room temperature, even in relatively large chunks.
melting and welding of titanium is carried out in a vacuum or in an atmosphere of neutral gas, in the liquid state because the oxide film does not protect the metal from reacting with oxygen.Titanium is able to absorb hydrogen and atmospheric gases, wherein the brittle alloys are formed, which are not suitable for practical use.
Titanium is resistant to nitric acid in any concentration, with the exception of red fuming, it causes cracking of the metal, and the reaction can take place with the explosion.With titanium react following acids: hydrochloric acid, concentrated sulfuric, hydrofluoric, oxalic, formic and trichloroacetic.
commercial titanium is used for the manufacture of tanks, pipes, pumps, valves and other products that are always in harsh environments.They cover parts made of steel, is used for the manufacture of food processing equipment, as well as in reconstructive surgery.
- HiMiK.ru Titan (chem. Element)