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Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine.

Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride (TiCl3), which is used as a catalyst in the production of polypropylene.

Titanium can be alloyed with iron, aluminium, vanadium, and molybdenum, among other elements, to produce strong, lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial processes (chemicals and petrochemicals, desalination plants, pulp, and paper), automotive, agriculture (farming), medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.

The two most useful properties of the metal are corrosion resistance and strength-to-density ratio, the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels, but less dense. There are two allotropic forms and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Although they have the same number of valence electrons and are in the same group in the periodic table, titanium and zirconium differ in many chemical and physical properties.

Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density and high strength. It is highly resistant to corrosion in sea water, aqua regia and chlorine.

Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and named by Martin Heinrich Klaproth for the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, rocks, water bodies, and soils.<ref name=“EBC”/> The metal is extracted from its principal mineral ores via the Kroll process<ref name=“LANL”/> or the Hunter process. Its most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments.<ref name=“HistoryAndUse”>

</ref> Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride (TiCl3), which is used as a catalyst in the production of polypropylene.<ref name=“EBC”/>

Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial process (chemicals and petro-chemicals, desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.<ref name=“EBC”/>

The two most useful properties of the metal are corrosion resistance and the highest strength-to-density ratio of any metallic element.<ref>

</ref> In its unalloyed condition, titanium is as strong as some steels, but 45% less dense.<ref name=“Barksdale1968p738”>

</ref> There are two allotropic forms<ref name=“TICE6th”>

</ref> and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant (73.8%).<ref name=“EnvChem”>

</ref> Titanium's properties are chemically and physically similar to zirconium, as both of them have the same number of valence electrons and are in the same group in the periodic table.


Physical properties

A metallic element, titanium is recognized for its high strength-to-weight ratio.<ref name=“TICE6th”/> It is a strong metal with low density that is quite ductile (especially in an oxygen-free environment),<ref name=“EBC”>

</ref> lustrous, and metallic-white in color.<ref name=“Stwertka1998”/> The relatively high melting point (more than 1,650&nbsp;°C or 3,000&nbsp;°F) makes it useful as a refractory metal. It is paramagnetic and has fairly low electrical and thermal conductivity.<ref name=“EBC”/>

Commercial (99.2% pure) grades of titanium have ultimate tensile strength of about 434 MPa (63,000 psi), equal to that of common, low-grade steel alloys, but are 45% less dense. Titanium is 60% more dense than aluminium, but more than twice as strong<ref name=“Barksdale1968p738”/> as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys (e.g., Beta C) achieve tensile strengths of over 1400 MPa (200000 psi).<ref>

</ref> However, titanium loses strength when heated above

.<ref name=“Barksdale1968p734”>


Titanium is fairly hard (although not as hard as some grades of heat-treated steel), non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, as the material will soften and gall if sharp tools and proper cooling methods are not used. Like those made from steel, titanium structures have a fatigue limit which guarantees longevity in some applications.<ref name=“Stwertka1998”/> Titanium alloys have lower specific stiffnesses than in many other structural materials such as aluminium alloys and carbon fiber.

The metal is a dimorphic allotrope whose hexagonal alpha form changes into a body-centered cubic (lattice) β form at

.<ref name=“Barksdale1968p734”/> The specific heat of the alpha form increases dramatically as it is heated to this transition temperature but then falls and remains fairly constant for the β form regardless of temperature.<ref name=“Barksdale1968p734”/> Similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but is metastable at ambient pressures. This phase is usually hexagonal (ideal) or trigonal (distorted) and can be viewed as being due to a soft longitudinal acoustic phonon of the β phase causing collapse of (111) planes of atoms.<ref>


Chemical properties

for titanium in pure water, perchloric acid or sodium hydroxide<ref name=“medusa”>Puigdomenech, Ignasi (2004) ''Hydra/Medusa Chemical Equilibrium Database and Plotting Software'', KTH Royal Institute of Technology.</ref>]] Like aluminium and magnesium metal surfaces, titanium metal and its alloys oxidize immediately upon exposure to air. Nitrogen acts similarly to give a coating of the nitride. Titanium readily reacts with oxygen at

in air, and at

in pure oxygen, forming titanium dioxide.<ref name=“TICE6th”/> It is, however, slow to react with water and air, as it forms a passive and oxide coating that protects the bulk metal from further oxidation.<ref name=“EBC”/> When it first forms, this protective layer is only 1–2 nm thick but continues to slowly grow; reaching a thickness of 25&nbsp;nm in four years.<ref name=“Emsley2001p453”/>

Related to its tendency to form a passivating layer, titanium exhibits excellent resistance to corrosion. It is almost as resistant as platinum, capable of withstanding attack by dilute sulfuric and hydrochloric acids as well as chloride solutions, and most organic acids.<ref name=“LANL”/> However, it is attacked by concentrated acids.<ref>

</ref> As indicated by its negative redox potential, titanium is thermodynamically a very reactive metal. One indication is that the metal burns before its melting point is reached. Melting is only possible in an inert atmosphere or in a vacuum. At

, it combines with chlorine.<ref name=“LANL”/> It also reacts with the other halogens and absorbs hydrogen.<ref name=“HistoryAndUse”/>

Titanium is one of the few elements that burns in pure nitrogen gas, reacting at

to form titanium nitride, which causes embrittlement.<ref name=“titaniumindustry”>

</ref> Because of its high reactivity toward oxygen, nitrogen and many other gases, titanium filaments are applied in titanium sublimation pumps as scavengers for these gases. Such pumps are inexpensive and reliable devices for producing extremely low pressures in ultra-high vacuum systems.


2011 production of rutile and ilmenite<ref name=USGS/>
Country thousand <br>tonnes % of total
Australia 1300 19.4
South Africa 1160 17.3
Canada 700 10.4
India 574 8.6
Mozambique 516 7.7
China 500 7.5
Vietnam 490 7.3
Ukraine 357 5.3
World 6700 100

Titanium is always bonded to other elements in nature. It is the ninth-most abundant element in the Earth's crust (0.63% by mass)<ref name=“Barksdale1968p732”/> and the seventh-most abundant metal. It is present in most igneous rocks and in sediments derived from them (as well as in living things and natural bodies of water).<ref name=“EBC”/><ref name=“LANL”>

</ref> Of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium. Its proportion in soils is approximately 0.5 to 1.5%.<ref name=“Barksdale1968p732”/>

It is widely distributed and occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile and titanite (sphene).<ref name=“Emsley2001p453”>

</ref> Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of these minerals have been mined in 2011, respectively.<ref name=USGS/> Significant titanium-bearing ilmenite deposits exist in western Australia, Canada, China, India, Mozambique, New Zealand, Norway, Ukraine and South Africa.<ref name=“Emsley2001p453”/> About 186,000 tonnes of titanium metal sponge were produced in 2011, mostly in China (60,000 t), Japan (56,000 t), Russia (40,000 t), United States (32,000 t) and Kazakhstan (20,700 t). Total reserves of titanium are estimated to exceed 600 million tonnes.<ref name=USGS/>

Titanium is contained in meteorites and has been detected in the sun and in M-type stars,<ref name=“LANL”/> which are the coolest type of star, with a surface temperature of

.<ref name=“Emsley2001p451”>

</ref> Rocks brought back from the moon during the Apollo 17 mission are composed of 12.1% TiO2.<ref name=“LANL”/> It is also found in coal ash, plants, and even the human body.


Naturally occurring titanium is composed of 5 stable isotopes: 46Ti, 47Ti, 48Ti, 49Ti, and 50Ti, with 48Ti being the most abundant (73.8% natural abundance). Eleven radioisotopes have been characterized, with the most stable being 44Ti with a half-life of 63 years, 45Ti with a half-life of 184.8 minutes, 51Ti with a half-life of 5.76 minutes, and 52Ti with a half-life of 1.7 minutes. All of the remaining radioactive isotopes have half-lives that are less than 33 seconds and the majority of these have half-lives that are less than half a second.<ref name=“EnvChem”/>

The isotopes of titanium range in atomic weight from 39.99 u (40Ti) to 57.966 u (58Ti). The primary decay mode before the most abundant stable isotope, 48Ti, is electron capture and the primary mode after is beta emission. The primary decay products before 48Ti are element 21 (scandium) isotopes and the primary products after are element 23 (vanadium) isotopes.<ref name=“EnvChem”/>

Titanium becomes radioactive upon bombardment with deuterons, emitting mainly positrons and hard gamma rays.<ref name=“LANL”/>


bit]] The +4 oxidation state dominates titanium chemistry,<ref name=“Greenwood1997p958”>

</ref> but compounds in the +3 oxidation state are also common.<ref name=“Greenwood1997p970”>

</ref> Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl4 is a notable exception. Because of the high oxidation state of Ti(IV), titanium(IV) compounds exhibit a high degree of covalent bonding.

Oxides, sulfides, and alkoxides

The most important oxide is TiO2, which exists in three important polymorphs, anatase, brookite, and rutile. All of these are white diamagnetic solids, although mineral samples can appear dark (see rutile). The adopt polymeric structures in which Ti is surrounded by six oxide ligands that link to other Ti centers. Titanates usually refers to compounds made from titanium dioxide, as represented barium titanate (BaTiO3), which is produced synthetically. With a perovskite structure, this material exhibits piezoelectric properties and is used as a transducer in the interconversion of sound and electricity.<ref name=“TICE6th”/> Many minerals are titanates, e.g. illmenite (FeTiO3). Star sapphires and rubies get their asterism (star-forming shine) from the presence of titanium dioxide impurities.<ref name=“Emsley2001p453”/>

The alkoxides of titanium(IV) are useful compounds that convert to the dioxide. They are volatile, colourless compounds that are sensitive to water. Titanium ethoxide, with the molecular formula Ti4(OEt)16, reacts with water to deposit solid TiO2 via the sol-gel process. Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation.

Titanium forms a variety of sulfides, but only TiS<sub>2</sub> has attracted significant interest. It adopts a layered structure and was used as a cathode in early generation of lithium batteries. Since Ti(IV) is a "hard cation", the sulfides of titanium are unstable in the presence of moisture, tending to hydrolyze to the oxide and hydrogen sulfide.

Nitrides, carbides

Titanium nitride (TiN), having a hardness equivalent to sapphire and carborundum (9.0 on the Mohs Scale),<ref>

</ref> is often used to coat cutting tools, such as drill bits.<ref>

</ref> It also finds use as a gold-colored decorative finish, and as a barrier metal in semiconductor fabrication.<ref>

</ref> Titanium carbide, which is also very hard, is found in high-temperature cutting tools and coatings).


Titanium tetrachloride (titanium(IV) chloride, TiCl4<ref>

</ref>) is a colorless volatile liquid (commercial samples are yellowish) that in air hydrolyzes with spectacular emissoin of white clouds. Via the Kroll process, TiCl4 is produced in the conversion of titanium ores to titanium dioxide, e.g., for use in white paint.<ref>

</ref> It is widely used in organic chemistry as a Lewis acid, for example in the Mukaiyama aldol condensation.<ref>

</ref> In the van Arkel process, titanium tetraiodide (TiI4) is generated in the production of high purity titanium metal.


Titanium(III) and titanium(II) also form stable chlorides. A notable example is titanium(III) chloride (TiCl3), which is used as a catalyst for production of polyolefins (see Ziegler-Natta catalyst) and a reducing agent in organic chemistry.

Organometallic complexes

Owing to the important role of titanium compounds as polymerization catalyst, compounds with Ti-C bonds have been intensively studied. The most common organotitanium complex is titanocene dichloride ((C5H5)2TiCl2). Related compounds include Tebbe's reagent and Petasis reagent. Titanium forms carbonyl complexes, e.g. (C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>Ti(CO)<sub>2</sub>.<ref>Hartwig, J. F. Organotransition Metal Chemistry, from Bonding to Catalysis; University Science Books: New York, 2010. ISBN 189138953X</ref>


named titanium for the Titans of Greek mythology.]] Titanium was discovered included in a mineral in Cornwall, Great Britain, in 1791 by the clergyman and amateur geologist William Gregor, then vicar of Creed parish.<ref name=“Emsley2001p452” /> He recognized the presence of a new element in ilmenite<ref name=“HistoryAndUse”/> when he found black sand by a stream in the nearby parish of Manaccan and noticed the sand was attracted by a magnet.<ref name=“Emsley2001p452” /> Analysis of the sand determined the presence of two metal oxides; iron oxide (explaining the attraction to the magnet) and 45.25% of a white metallic oxide he could not identify.<ref name=“Barksdale1968p732”>

</ref> Gregor, realizing that the unidentified oxide contained a metal that did not match the properties of any known element, reported his findings to the Royal Geological Society of Cornwall and in the German science journal Crell's Annalen.<ref name=“Emsley2001p452” /><!–<ref>


Around the same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it.<ref name=“HistoryAndUse”/> The oxide was independently rediscovered in 1795 by Prussian chemist Martin Heinrich Klaproth in rutile from Boinik (German name of unknown place) village of Hungary (Now in Slovakia).<ref name=“Emsley2001p452” /> Klaproth found that it contained a new element and named it for the Titans of Greek mythology.<ref name=“Emsley2001p451”/> After hearing about Gregor's earlier discovery, he obtained a sample of manaccanite and confirmed it contained titanium.

The processes required to extract titanium from its various ores are laborious and costly; it is not possible to reduce the ore in the normal manner, by heating in the presence of carbon, as that produces titanium carbide.<ref name=“Emsley2001p452” /> Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl4 with sodium at 700–800&nbsp;°C in the Hunter process.<ref name=“LANL”/> Titanium metal was not used outside the laboratory until 1932 when William Justin Kroll proved that it could be produced by reducing titanium tetrachloride (TiCl4) with calcium.<ref name=“Greenwood1997p955”>

</ref> Eight years later he refined this process by using magnesium and even sodium in what became known as the Kroll process.<ref name=“Greenwood1997p955”/> Although research continues into more efficient and cheaper processes (e.g., FFC Cambridge), the Kroll process is still used for commercial production.<ref name=“LANL”/><ref name=“HistoryAndUse”/>


Titanium of very high purity was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide, or crystal bar, process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal.<ref>


In the 1950s and 1960s the Soviet Union pioneered the use of titanium in military and submarine applications (Alfa Class and Mike Class)<ref>

</ref> as part of programs related to the Cold War.<ref>

</ref> Starting in the early 1950s, titanium began to be used extensively for military aviation purposes, particularly in high-performance jets, starting with aircraft such as the F100 Super Sabre and Lockheed A-12.

In the USA, the Department of Defense realized the strategic importance of the metal<ref>

</ref> and supported early efforts of commercialization.<ref>


Throughout the period of the Cold War, titanium was considered a strategic material by the U.S. government, and a large stockpile of titanium sponge was maintained by the Defense National Stockpile Center, which was finally depleted in the 2000s.<ref>

</ref> According to 2006 data, the world's largest producer, Russian-based VSMPO-Avisma, was estimated to account for about 29% of the world market share.<ref>

</ref> As of 2009, titanium sponge metal was produced in six countries: China, Japan, Russia, Kazakhstan, USA and Ukraine (in order of output).<ref>“Roskill Information Services: Global Supply of Titanium is Forecast to Increase”, Titanium Metal: Market Outlook to 2015 (5th edition, 2010), October 19, 2010,, accessed 2013-05-10.</ref>

In 2006, the U.S. Defense Agency awarded $5.7 million to a two-company consortium to develop a new process for making titanium metal powder. Under heat and pressure, the powder can be used to create strong, lightweight items ranging from armor plating to components for the aerospace, transport, and chemical processing industries.<ref>

</ref> <!– DUBIOUS SOURCE In 2008, materials scientists from Afton Chemical Corporation and the National Institute of Standards and Technology (NIST) established that a titanium compound added to engine oil creates a wear-resistant nanoscale layer bound to the surface of vulnerable engine parts, making it a credible substitute for older compounds that do not coexist well with antipollution equipment.<ref>Slippery Customer: A Greener Antiwear Additive for Engine Oils Newswise, Retrieved on July 22, 2008.</ref> Titanium is one candidate replacement of poisonous phosphorus compounds found in most engine oils.–>

Production and fabrication

The processing of titanium metal occurs in 4 major steps:<ref>

</ref> reduction of titanium ore into “sponge”, a porous form; melting of sponge, or sponge plus a master alloy to form an ingot; primary fabrication, where an ingot is converted into general mill products such as billet, bar, plate, sheet, strip, and tube; and secondary fabrication of finished shapes from mill products. <!– NEED BETER SOURCE Titanium Sponge is only produced in 7 countries<ref>States / Kerala : KMML starts producing titanium sponge. The Hindu (2011-09-17). Retrieved on 2011-10-10.</ref> by 19 companies.<ref>Forbes India Magazine – India Is Seventh Nation to Process Titanium Sponge. Retrieved on 2011-10-10.</ref> –>

Because the metal reacts with oxygen at high temperatures it cannot be produced by reduction of its dioxide.<ref name=“Stwertka1998”>

</ref> Titanium metal is therefore produced commercially by the Kroll process, a complex and expensive batch process. (The relatively high market value of titanium is mainly due to its processing, which sacrifices another expensive metal, magnesium.<ref name=“Barksdale1968p733”>

</ref>) In the Kroll process, the oxide is first converted to chloride through carbochlorination, whereby chlorine gas is passed over red-hot rutile or ilmenite in the presence of carbon to make TiCl<sub>4</sub>. This is condensed and purified by fractional distillation and then reduced with 800&nbsp;°C molten magnesium in an argon atmosphere.<ref name=“TICE6th”/>

A more recently developed method, the FFC Cambridge process,<ref>

</ref><ref>The Economist magazine 16th February 2013 page 74</ref> may eventually replace the Kroll process. This method uses titanium dioxide powder (which is a refined form of rutile) as feedstock to make the end product which is either a powder or sponge. If mixed oxide powders are used, the product is an alloy manufactured at a much lower cost than the conventional multi-step melting process. The FFC Cambridge process may render titanium a less rare and expensive material for the aerospace industry and the luxury goods market, and could be seen in many products currently manufactured using aluminium and specialist grades of steel.

Common titanium alloys are made by reduction. For example, cuprotitanium (rutile with copper added is reduced), ferrocarbon titanium (ilmenite reduced with coke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced.<ref name=“TI_Encarta2005”>

</ref> :2 FeTiO3 + 7 Cl2 + 6 C → 2 TiCl4 + 2 FeCl3 + 6 CO (900&nbsp;°C) :TiCl4 + 2 Mg → 2 MgCl2 + Ti (1100&nbsp;°C)

About 50 grades of titanium and titanium alloys are designated and currently used, although only a couple of dozen are readily available commercially.<ref>

</ref> The ASTM International recognizes 31 Grades of titanium metal and alloys, of which Grades 1 through 4 are commercially pure (unalloyed). These four are distinguished by their varying degrees of tensile strength, as a function of oxygen content, with Grade 1 being the most ductile (lowest tensile strength with an oxygen content of 0.18%), and Grade 4 the least (highest tensile strength with an oxygen content of 0.40%).<ref name=“Emsley2001p453”/> The remaining grades are alloys, each designed for specific purposes, be it ductility, strength, hardness, electrical resistivity, creep resistance, resistance to corrosion from specific media, or a combination thereof.<ref>


The grades covered by ASTM and other alloys are also produced to meet Aerospace and Military specifications (SAE-AMS, MIL-T), ISO standards, and country-specific specifications, as well as proprietary end-user specifications for aerospace, military, medical, and industrial applications.<ref>


In terms of fabrication, all welding of titanium must be done in an inert atmosphere of argon or helium in order to shield it from contamination with atmospheric gases such as oxygen, nitrogen, or hydrogen.<ref name=“Barksdale1968p734”/> Contamination will cause a variety of conditions, such as embrittlement, which will reduce the integrity of the assembly welds and lead to joint failure. Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account the fact that the metal has a “memory” and tends to spring back. This is especially true of certain high-strength alloys.<ref>


</ref> Titanium cannot be soldered without first pre-plating it in a metal that is solderable.<ref>

</ref> The metal can be machined using the same equipment and via the same processes as stainless steel.<ref name=“Barksdale1968p734”/>


Titanium is used in steel as an alloying element (ferro-titanium) to reduce grain size and as a deoxidizer, and in stainless steel to reduce carbon content.<ref name=“EBC”/> Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron, manganese, molybdenum, and with other metals.<ref name=“ECE738”>

</ref> Applications for titanium mill products (sheet, plate, bar, wire, forgings, castings) can be found in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright-burning particles.

Pigments, additives and coatings

is the most commonly used compound of titanium]] About 95% of titanium ore extracted from the Earth is destined for refinement into titanium dioxide (

), an intensely white permanent pigment used in paints, paper, toothpaste, and plastics.<ref name=USGS>

</ref> It is also used in cement, in gemstones, as an optical opacifier in paper,<ref>

</ref> and a strengthening agent in graphite composite fishing rods and golf clubs.

powder is chemically inert, resists fading in sunlight, and is very opaque: this allows it to impart a pure and brilliant white color to the brown or gray chemicals that form the majority of household plastics.<ref name=“HistoryAndUse”/> In nature, this compound is found in the minerals anatase, brookite, and rutile.<ref name=“EBC”/> Paint made with titanium dioxide does well in severe temperatures, and stands up to marine environments.<ref name=“HistoryAndUse”/> Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond.<ref name=“LANL”/> In addition to being a very important pigment, titanium dioxide is also used in sunscreens due to its ability to protect skin by itself.<ref name=“Stwertka1998”/> Recently, titanium oxide has been put to use in air purifiers (as a filter coating), or in film used to coat windows on buildings so that when titanium oxide becomes exposed to UV light (either solar or artificial) and moisture in the air, reactive redox species like hydroxyl radicals are produced so that they can purify the air or keep window surfaces clean.<ref>


Aerospace and marine

Due to their high tensile strength to density ratio,<ref name=“TICE6th”/> high corrosion resistance,<ref name=“LANL”/> fatigue resistance, high crack resistance,<ref name=“Moiseyev”>

</ref> and ability to withstand moderately high temperatures without creeping, titanium alloys are used in aircraft, armor plating, naval ships, spacecraft, and missiles.<ref name=“LANL”/><ref name=“HistoryAndUse”/> For these applications titanium alloyed with aluminium, zirconium, nickel,<ref name=NYT7513 /> vanadium, and other elements is used for a variety of components including critical structural parts, fire walls, landing gear, exhaust ducts (helicopters), and hydraulic systems. In fact, about two thirds of all titanium metal produced is used in aircraft engines and frames.<ref name=“Emsley2001p454” /> The SR-71 "Blackbird" was one of the first aircraft to make extensive use of titanium within its structure, paving the way for its use in modern military and commercial aircraft. An estimated 59 metric tons (130,000 pounds) are used in the Boeing 777, 45 in the Boeing 747, 18 in the Boeing 737, 32 in the Airbus A340, 18 in the Airbus A330, and 12 in the Airbus A320. The Airbus A380 may use 77 metric tons, including about 11 tons in the engines.<ref>

</ref> In engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles. The titanium 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications.<ref>


Due to its high corrosion resistance to sea water, titanium is used to make propeller shafts and rigging and in the heat exchangers of desalination plants;<ref name=“LANL”/> in heater-chillers for salt water aquariums, fishing line and leader, and for divers' knives. Titanium is used to manufacture the housings and other components of ocean-deployed surveillance and monitoring devices for scientific and military use. The former Soviet Union developed techniques for making submarines with hulls of titanium alloys.<ref>

</ref> Techniques were developed in the Soviet Union to forge titanium in huge vacuum tubes.<ref name=NYT7513>




Welded titanium pipe and process equipment (heat exchangers, tanks, process vessels, valves) are used in the chemical and petrochemical industries primarily for corrosion resistance. Specific alloys are used in downhole and nickel hydrometallurgy applications due to their high strength (e. g.: titanium Beta C alloy), corrosion resistance, or combination of both. The pulp and paper industry uses titanium in process equipment exposed to corrosive media such as sodium hypochlorite or wet chlorine gas (in the bleachery).<ref>

</ref> Other applications include: ultrasonic welding, wave soldering,<ref>

</ref> and sputtering targets.<ref>


Titanium tetrachloride (TiCl4), a colorless liquid, is important as an intermediate in the process of making TiO2 and is also used to produce the Ziegler-Natta catalyst, and is used to iridize glass and because it fumes strongly in moist air it is also used to make smoke screens.<ref name=“Stwertka1998”/>

Consumer and architectural

Titanium metal is used in automotive applications, particularly in automobile or motorcycle racing, where weight reduction is critical while maintaining high strength and rigidity.<ref>

</ref> The metal is generally too expensive to make it marketable to the general consumer market, other than high-end products, particularly for the racing/performance market. Late model Corvettes have been available with titanium exhausts.<ref>


Titanium is used in many sporting goods: tennis rackets, golf clubs, lacrosse stick shafts; cricket, hockey, lacrosse, and football helmet grills; and bicycle frames and components. Although not a mainstream material for bicycle production, titanium bikes have been used by race teams and adventure cyclists.<ref>

</ref> Titanium alloys are also used in spectacle frames.<ref name=“Donachie2000”>

</ref> This results in a rather expensive, but highly durable and long lasting frame which is light in weight and causes no skin allergies. Many backpackers use titanium equipment, including cookware, eating utensils, lanterns, and tent stakes.<ref name=“Donachie2000” /> Though slightly more expensive than traditional steel or aluminium alternatives, these titanium products can be significantly lighter without compromising strength. Titanium is also favored for use by farriers, since it is lighter and more durable than steel when formed into horseshoes.<ref name=“Donachie2000” />

Titanium has occasionally been used in architectural applications: the 40 m (131&nbsp;foot) memorial to Yuri Gagarin, the first man to travel in space, in Moscow, is made of titanium for the metal's attractive color and association with rocketry.<ref>

</ref> The Guggenheim Museum Bilbao and the Cerritos Millennium Library were the first buildings in Europe and North America, respectively, to be sheathed in titanium panels.<ref name=“Emsley2001p454”>

</ref> Other construction uses of titanium sheathing include the Frederic C. Hamilton Building in Denver, Colorado<ref>

</ref> and the 107 m (350&nbsp;foot) Monument to the Conquerors of Space in Moscow.<ref>


Because of its superior strength and light weight when compared to other metals traditionally used in firearms (steel, stainless steel, and aluminium), and advances in metalworking techniques, the use of titanium has become more widespread in the manufacture of firearms. Primary uses include pistol frames and revolver cylinders. For these same reasons, it is also used in the body of laptop computers (for example, in Apple's PowerBook line).<ref>


Some upmarket categories of tools made to be lightweight and corrosion-resistant, such as shovels and flashlights, are made of titanium or titanium alloys as well.


Because of its durability, titanium has become more popular for designer jewelry (particularly, titanium rings).<ref name=“Donachie2000” /> Its inertness makes it a good choice for those with allergies or those who will be wearing the jewelry in environments such as swimming pools. Titanium is also alloyed with gold to produce an alloy that can be marketed as 24-carat gold, as the 1% of alloyed Ti is insufficient to require a lesser mark. The resulting alloy is roughly the hardness of 14-carat gold and thus is more durable than a pure 24-carat gold item would be.<ref>


Titanium's durability, light weight, dent- and corrosion resistance makes it useful in the production of watch cases.<ref name=“Donachie2000” /> Some artists work with titanium to produce artworks such as sculptures, decorative objects and furniture.<ref>


The inertness and ability to be attractively colored makes titanium a popular metal for use in body piercing.<ref>

</ref> Titanium may be anodized to produce various colors, which varies the thickness of the surface oxide layer and causes interference fringes.<ref>


The Gold Coast Titans, an Australian rugby league team, award a medal of pure titanium to their player of the year.<ref>



Because it is biocompatible (it is non-toxic and is not rejected by the body), titanium is used in a gamut of medical applications including surgical implements and implants, such as hip balls and sockets (joint replacement) that can stay in place for up to 20 years.<ref name=“Emsley2001p452”>

</ref> The titanium is often alloyed with about 4% aluminium<ref>

</ref> or 6% Al and 4% vanadium.

Titanium has the inherent ability to osseointegrate, enabling use in dental implants that can remain in place for over 30 years. This property is also useful for orthopedic implant applications.<ref name=“Emsley2001p452”/> These benefit from titanium's lower modulus of elasticity (Young's modulus) to more closely match that of the bone that such devices are intended to repair. As a result, skeletal loads are more evenly shared between bone and implant, leading to a lower incidence of bone degradation due to stress shielding and periprosthetic bone fractures, which occur at the boundaries of orthopedic implants. However, titanium alloys' stiffness is still more than twice that of bone, so adjacent bone bears a greatly reduced load and may deteriorate.<ref>


Since titanium is non-ferromagnetic, patients with titanium implants can be safely examined with magnetic resonance imaging (convenient for long-term implants). Preparing titanium for implantation in the body involves subjecting it to a high-temperature plasma arc which removes the surface atoms, exposing fresh titanium that is instantly oxidized.<ref name=“Emsley2001p452”/>

Titanium is also used for the surgical instruments used in image-guided surgery, as well as wheelchairs, crutches, and any other products where high strength and low weight are desirable.

Nuclear waste storage

Due to its extreme corrosion resistance, titanium containers have been studied for the long-term storage of nuclear waste (containers lasting over 100,000 years are possible under proper manufacturing conditions to reduce defects in the process).<ref>

</ref> A titanium “drip shield” could also be placed over other types of containers to further contain the waste.<ref>


<gallery> File:Titanium Piercing.JPG|A titanium body piercing. File:Titanium welds.jpg|alt= Titanium bicycle frame|Characteristic weld beads on a handmade titanium bicycle frame. File:GuggenheimBilbao.jpg|alt= Outside view of a several storey building with smooth irregular undulating walls. The largest part is coated with gray metal or made from glass|The Guggenheim Museum Bilbao is sheathed in titanium panels. File:Titanium-Rings-plain.jpg|A titanium ring. File:Titanium-spork 1.jpg|A titanium spork useful for backpackers. About 16 grams, lighter than a plastic utensil but stronger than a steel implement. File:Lateralcephplated.JPG|alt=Grayscale x-ray image of a human skull. This left lateral cephalametric radiograph shows a profile of the human skull. The maxilla and some crowned teeth make up most of the image. Above that four faint nail like structures are visible.|A fracture of the eye socket was repaired by stabilizing the fractured bones with small titanium plates and screws.</gallery>


The fungal species Marasmius oreades and Hypholoma capnoides can bio convert titanium in titanium polluted soils. <ref>



contains up to 80 parts per million of titanium.]] Titanium is non-toxic even in large doses and does not play any natural role inside the human body.<ref name=“Emsley2001p451” /> An estimated quantity of 0.8 milligrams of titanium is ingested by humans each day, but most passes through without being absorbed.<ref name=“Emsley2001p451”/> It does, however, have a tendency to bio-accumulate in tissues that contain silica. One study indicates a possible connection between titanium and yellow nail syndrome.<ref>

</ref> An unknown mechanism in plants may use titanium to stimulate the production of carbohydrates and encourage growth. This may explain why most plants contain about 1 part per million (ppm) of titanium, food plants have about 2 ppm, and horsetail and nettle contain up to 80 ppm.<ref name=“Emsley2001p451” />

As a powder or in the form of metal shavings, titanium metal poses a significant fire hazard and, when heated in air, an explosion hazard.<ref>

</ref> Water and carbon dioxide–based methods to extinguish fires are ineffective on burning titanium; Class D dry powder fire fighting agents must be used instead.<ref name=“HistoryAndUse”/>

When used in the production or handling of chlorine, care must be taken to use titanium only in locations where it will not be exposed to dry chlorine gas which can result in a titanium/chlorine fire.<ref>

</ref> A fire hazard exists even when titanium is used in wet chlorine due to possible unexpected drying brought about by extreme weather conditions.

Titanium can catch fire when a fresh, non-oxidized surface comes in contact with liquid oxygen.<ref>

</ref> Such surfaces can appear when the oxidized surface is struck with a hard object, or when a mechanical strain causes the emergence of a crack. This poses the possible limitation for its use in liquid oxygen systems, such as those found in the aerospace industry.

See also



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titanium.txt · Last modified: 2020/03/12 18:39 (external edit)