The two most useful properties of the metal are its corrosion resistance andstrength-to-density ratio, the highest of any metallic element.[15] In its unalloyed condition, titanium is as strong as somesteels, but less dense.[16] There are twoallotropic forms[17] and five naturally occurringisotopes of this element,46Ti through50Ti, with48Ti being the mostabundant (73.8%).[18]
Commercially pure (99.2% pure)grades of titanium haveultimate tensile strength of about 434 MPa (63,000 psi), equal to that of common, low-grade steel alloys, but are less dense. Titanium is 60% denser than aluminium, but more than twice as strong[16] as the most commonly used6061-T6 aluminium alloy. Certain titanium alloys (e.g.,Beta C) achieve tensile strengths of over 1,400 MPa (200,000 psi).[23] However, titanium loses strength when heated above 430 °C (806 °F).[24]
Titanium is not as hard as some grades of heat-treated steel; it is non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, because the material cangall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have afatigue limit that guarantees longevity in some applications.[19]
The metal is a dimorphicallotrope of ahexagonal close packed α form that changes into abody-centered cubic (lattice) β form at 882 °C (1,620 °F).[24][25] Thespecific heat of the α 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.[24]
Chemical properties
Pourbaix diagram for titanium in pure water, perchloric acid, or sodium hydroxide[26]
Likealuminium andmagnesium, the surface of titanium metal and its alloysoxidizes immediately upon exposure to air to form a thin non-porouspassivation layer that protects the bulk metal from further oxidation or corrosion.[11] When it first forms, this protective layer is only 1–2 nm thick but it continues to grow slowly, reaching a thickness of 25 nm in four years.[27] This layer gives titanium excellent resistance to corrosion against oxidizing acids, but it will dissolve in dilutehydrofluoric acid, hot hydrochloric acid, and hot sulfuric acid.[28]
Titanium is capable of withstanding attack by dilutesulfuric andhydrochloric acids at room temperature, chloride solutions, and most organic acids.[12] However, titanium is corroded by concentrated acids.[29] Titanium burns in normal air at temperatures lower than its melting point, so melting the metal is possible only in an inert atmosphere or vacuum.[12] At room temperature, titanium is fairly inert tohalogens, but will violently combine withchlorine andbromine at 550 °C (1,022 °F) to formtitanium tetrachloride andtitanium tetrabromide, respectively.[28]
Titanium readily reacts with oxygen at 1,200 °C (2,190 °F) in air, and at 610 °C (1,130 °F) in pure oxygen, formingtitanium dioxide.[17] This oxide is also formed by reaction between titanium and pure oxygen at room temperature and pressure of 25 bars (2,500 kPa).[28] Titanium is one of the few elements that burns in pure nitrogen gas, reacting at 800 °C (1,470 °F) to formtitanium nitride, which causes embrittlement.[30]
Occurrence
Titanium is the ninth-mostabundant element inEarth's crust (0.63% bymass)[31] and the seventh-most abundant metal. It is present as oxides in mostigneous rocks, insediments derived from them, in living things, and natural bodies of water.[11][12] Of the 801 types of igneous rocks analyzed by theUnited States Geological Survey, 784 contained titanium. Its proportion in soils is approximately 0.5–1.5%.[31]
The concentration of titanium is about 4picomolar in the ocean. At 100 °C, the concentration of titanium in water is estimated to be less than 10−7 M at pH 7. The identity of titanium species in aqueous solution remains unknown because of its low solubility and the lack of sensitive spectroscopic methods, although only the 4+ oxidation state is stable in air. No evidence exists for a biological role, although rare organisms are known to accumulate high concentrations of titanium.[33]
Titanium is contained inmeteorites, and it has been detected in theSun and inM-typestars[12] (the coolest type) with a surface temperature of 3,200 °C (5,790 °F).[34]Rocks brought back from theMoon during theApollo 17 mission are composed of 12.1% TiO2.[12]Native titanium is only found in rocks that have been exposed to pressures between roughly 2.8 to 4.0gigapascal on Earth,[35] but it has been identified innanocrystals on the Moon.[36]
Naturally occurring titanium is composed of five stableisotopes:46Ti,47Ti,48Ti,49Ti, and50Ti, with48Ti being the most abundant (73.8%natural abundance). Twenty-threeradioisotopes have been characterized,[b] the most stable of which are44Ti with ahalf-life of 63 years;45Ti, 184.8 minutes;51Ti, 5.76 minutes; and52Ti, 1.7 minutes. All otherradioactive isotopes have half-lives less than 33 seconds, with the majority less than half a second.[18][37]
The +4oxidation state dominates titanium chemistry,[40] but compounds in the +3 oxidation state are also numerous.[41] Commonly, titanium adopts anoctahedral coordination geometry in its complexes,[42][43] but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree ofcovalent bonding.[40]
Oxides, sulfides, and alkoxides
The most important oxide is TiO2, which exists in three importantpolymorphs; anatase, brookite, and rutile. All three are white diamagnetic solids, although mineral samples can appear dark, as inrutile. They adopt polymeric structures in which Ti is surrounded by sixoxide ligands that link to other Ti centers.[44]
The termtitanates usually refers to titanium(IV) compounds, as represented bybarium titanate (BaTiO3). With a perovskite structure, this material exhibitspiezoelectric properties and is used as a transducer in the interconversion ofsound andelectricity.[17] Many minerals are titanates, such as ilmenite (FeTiO3).Star sapphires andrubies get theirasterism (star-forming shine) from the presence of titanium dioxide impurities.[27]
A variety of reduced oxides (suboxides) of titanium are known, mainly reducedstoichiometries of titanium dioxide obtained byatmospheric plasma spraying. Ti3O5, described as a Ti(IV)-Ti(III) species, is a purple semiconductor produced byreduction of TiO2 with hydrogen at high temperatures,[45] and is used industrially when surfaces need to be vapor-coated with titanium dioxide: it evaporates as pure TiO, whereas TiO2 evaporates as a mixture of oxides and deposits coatings with variable refractive index.[46] Also known isTi2O3, with thecorundum structure, andTiO, with therock salt structure, although oftennonstoichiometric.[47]
Thealkoxides of titanium(IV), prepared by treating TiCl4 withalcohols, are colorless compounds that convert to the dioxide on reaction with water. They are industrially useful for depositing solid TiO2 via thesol-gel process.Titanium isopropoxide is used in the synthesis of chiral organic compounds via theSharpless epoxidation.[48]
Titanium forms a variety of sulfides, but onlyTiS2 has attracted significant interest. It adopts a layered structure and was used as a cathode in the development oflithium batteries. Because Ti(IV) is a"hard cation", the sulfides of titanium are unstable and tend to hydrolyze to the oxide with release ofhydrogen sulfide.[49]
Titanium(III) compounds are characteristically violet, illustrated by this aqueous solution oftitanium trichloride.
Titanium tetrachloride (titanium(IV) chloride, TiCl4[55]) is a colorless volatile liquid (commercial samples are yellowish) that, in air, hydrolyzes with spectacular emission of white clouds. Via theKroll process, TiCl4 is used in the conversion of titanium ores to titanium metal. Titanium tetrachloride is also used to make titanium dioxide, e.g., for use in white paint.[56] It is widely used inorganic chemistry as aLewis acid, for example in theMukaiyama aldol condensation.[57] In thevan Arkel–de Boer process,titanium tetraiodide (TiI4) is generated in the production of high purity titanium metal.[58]
Titanium wasdiscovered in 1791 by theclergyman andgeologistWilliam Gregor as aninclusion of a mineral inCornwall, Great Britain.[61] Gregor recognized the presence of a new element in ilmenite[13] when he found black sand by a stream and noticed the sand was attracted by amagnet.[61] Analyzing the sand, he 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.[31] Realizing that the unidentified oxide contained a metal that did not match any known element, in 1791 Gregor reported his findings in both German and French science journals:Crell's Annalen andObservations et Mémoires sur la Physique.[61][62][63] He named this oxidemanaccanite.[64]
Around the same time,Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it.[13] The oxide was independently rediscovered in 1795 byPrussian chemistMartin Heinrich Klaproth in rutile from Boinik (the German name of Bajmócska), a village in Hungary (nowBojničky in Slovakia).[61][c]Klaproth found that it contained a new element and named it for theTitans ofGreek mythology.[34] After hearing about Gregor's earlier discovery, he obtained a sample of manaccanite and confirmed that it contained titanium.[66]
The currently known processes for extracting titanium from its various ores are laborious and costly; it is not possible to reduce the ore by heating withcarbon (as in iron smelting) because titanium combines with the carbon to produce titanium carbide.[61] An extraction of 95% pure titanium was achieved byLars Fredrik Nilson andOtto Petterson. To achieve this they chlorinated titanium oxide in a carbon monoxide atmosphere with chlorine gas before reducing it to titanium metal by the use of sodium.[67] Pure metallic titanium (99.9%) was first prepared in 1910 byMatthew A. Hunter atRensselaer Polytechnic Institute by heating TiCl4 withsodium at 700–800 °C (1,292–1,472 °F) under great pressure[68] in abatch process known as theHunter process.[12] Titanium metal was not used outside the laboratory until 1932 whenWilliam Justin Kroll produced it by reducing titanium tetrachloride (TiCl4) withcalcium.[69] Eight years later he refined this process with magnesium and with sodium in what became known as theKroll process.[69] Although research continues to seek cheaper and more efficient routes, such as theFFC Cambridge process, the Kroll process is still predominantly used for commercial production.[12][13]
Titanium of very high purity was made in small quantities whenAnton Eduard van Arkel andJan Hendrik de Boer discovered the iodide process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal.[70]
In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications[68] (Alfa class andMike class)[71] as part of programs related to the Cold War.[72] Starting in the early 1950s, titanium came into use extensively in military aviation, particularly in high-performance jets, starting with aircraft such as theF-100 Super Sabre andLockheed A-12 andSR-71.[73]
Throughout the Cold War period, titanium was considered astrategic material by the U.S. government, and a large stockpile of titaniumsponge (a porous form of the pure metal) was maintained by theDefense National Stockpile Center, until the stockpile was dispersed in the 2000s.[74] Even so, the U.S. government annually allocates 15,000metric tons of titanium sponge as potential acquisitions for the stockpile.[75]
Titanium production is largely divided into three measured categories: manufacture of porous titanium metal "sponge", titanium oxide pigment, and titanium mineral concentrates used for the production of sponge, pigment, metal ingots, and other titanium products such as coatings. These concentrates are largely made up of the mineralilmenite, but also includeanatase, natural and syntheticrutile,tailings,slag, andleucoxene. As of 2024, the largest producers of titanium mineral concentrates wereChina,Mozambique, andSouth Africa.[75]
Most of the world's titanium is produced in China. TheUnited States Geological Survey's 2025 report on mineral commodities estimated that out of the 320,000 metric tons (310,000 long tons) of titanium sponge produced globally in 2024, 220,000 (69%) were produced in China, with the second-largest producer beingJapan (which produced 55,000metric tons in the same year, 17% of the total). Japan was the largest exporter of titanium sponge in 2024, but did not produce any titanium minerals on its own.[75] A prior report in 2021 noted that the four leading producers of titanium sponge were China (52%), Japan (24%), Russia (16%) and Kazakhstan (7%).[32] Russia remains the third-largest producer of titanium sponge[75] through the efforts of the metallurgy companyVSMPO-AVISMA, despiteinternational sanctions during the Russian invasion of Ukraine.[76] Production statistics on titanium dioxide pigment are not as clear-cut, but estimates placed the maximum capacity on global pigment production at 9,800,000 metric tons (9,600,000 long tons) in 2024.[75]
Various methods have been developed to extract and refine titanium from ore since the metal was first purified in 1910.[28][77]
Mineral beneficiation processes
Mineral concentrate of fine-grained titanium
Several processes have been developed to extract titanium and usable titanium-containing minerals from ore. TheBecher process is an industrial process used to produce synthetic rutile, a form of titanium dioxide, from the ore ilmenite by removing iron.[78] It is not used at scale.[77] Thechloride process produces titanium tetrachloride through treatment of rutile ore with chlorine and carbon at high heat,[42] then oxidizes the product with an oxygen flame or plasma to produce titanium dioxide.[79] Thesulfate process usessulfuric acid (H2SO4) to leach titanium from ilmenite ore (FeTiO3), producingtitanyl sulfate (TiOSO4). This sulfate is broken into two hydrates,TiO2 andH2SO4, through addition of water, and this water is removed by adding heat, which produces titanium dioxide as the end product.[80]
The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 byMatthew A. Hunter, achemist born in New Zealand who worked in the United States.[81] The process involves reducingtitanium tetrachloride (TiCl4) withsodium (Na) in a batch reactor with an inert atmosphere at a temperature of 1,000 °C. Dilutehydrochloric acid is then used to leach the salt from the product.[82]
TiCl4(g) + 4 Na(l) → 4 NaCl(l) + Ti(s)
Kroll process
Sample of titanium tetrachloride, a volatile liquid
The processing of titanium metal occurs in four major steps: 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 asbillet, bar,plate,sheet, strip, andtube; and secondary fabrication of finished shapes from mill products.[83]
Because it cannot be readily produced by reduction of titanium dioxide,[19] titanium metal is obtained by reduction oftitanium tetrachloride (TiCl4) with magnesium metal in the Kroll process. The complexity of this batch production in the Kroll process explains the relatively high market value of titanium,[84] despite the Kroll process being less expensive than the Hunter process.[68] To produce the TiCl4 required by the Kroll process, the dioxide is subjected tocarbothermic reduction in the presence ofchlorine. In this process, the chlorine gas is passed over a red-hot mixture of rutile or ilmenite in the presence of carbon. After extensive purification byfractional distillation, the TiCl4 is reduced with 800 °C (1,470 °F) molten magnesium in anargon atmosphere.[17]
Arkel-Boer process
Thevan Arkel–de Boer process was the first semi-industrial process developed to produce pure titanium, invented byAnton Eduard van Arkel andJan Hendrik de Boer in 1925 for the electronics companyPhilips.[85] It is a closed-loop process[86] that involves thermal decomposition oftitanium tetraiodide.[87] This same process is used to purify other metals, such as thorium, hafnium, and zirconium,[85] and a similar process using further refined iodide was used to refine chromium. A desire to develop processes that could be run continuously led to the development of commercial processes to refine titanium.[86]
Armstrong process
Titanium powder is manufactured using aflow production process known as theArmstrong process[88] that is similar to the batch productionHunter process. A stream of titanium tetrachloride gas is added to a stream of molten sodium; the products (sodium chloride salt and titanium particles) are filtered from the extra sodium. Titanium is then separated from the salt by water washing. Both the sodium and chlorine are recycled to produce and process more titanium tetrachloride.[89]
Other processes
The titanium tetrachloride used as an intermediate in both the Hunter and Kroll process is a volatile and corrosive liquid, and is thus hazardous to work with. The processes involving the tetrachloride, both its formation and the vacuum distillation processes used to purify the final material, are slow, and have prompted development of other techniques.[90]
Methods forelectrolytic production of Ti metal fromTiO2 using molten salt electrolytes have been proposed starting in the 1990s,[90] and have been researched and tested at laboratory and small pilot plant scales.[91] While some metals such asnickel andcopper can be refined byelectrowinning at room temperature, titanium must be in the molten state, which is likely to damage therefractory lining of a reaction vessel.[92] Zhang and colleagues concluded in 2017 that despite industry interests in finding new ways to manufacture titanium metal, no method had yet been developed to commercially replace the Kroll process.[93] One manufacturer in Virginia has developed a method to recycle scrap titanium metal back into powder, though their scale remains small, having the goal of producing only 125 tons of titanium per year as of 2025.[75]
One method that has been developed to potentially supplant the Kroll process is known ashydrogen-assisted magnesiothermic reduction and makes use ofmagnesium, hydrochloric acid, and a hydrogen atmosphere to directly reduce titanium dioxide to pure titanium. The reduction of titanium dioxide powder by magnesium in an atomphere of hydrogen can be followed by a leaching step with hydrochloric acid, which removes magnesium and residual non-titanium oxides. This is followed by additional reduction and leaching steps, and eventually results in pure titanium powder ortitanium hydride.[94]
Fabrication
Allwelding of titanium must be done in an inert atmosphere of argon orhelium to shield it from contamination with atmospheric gases (oxygen, nitrogen, and hydrogen).[24] Contamination causes a variety of conditions, such asembrittlement, which reduce the integrity of the assembly welds and lead to joint failure.[95]
Titanium is very difficult tosolder directly, and hence asolderable metal or alloy such as steel is coated on titanium prior to soldering.[96] Titanium metal can be machined with the same equipment and the same processes asstainless steel.[24]
Basic titanium products: plate, tube, rods, and powder
Commontitanium alloys are made by reduction. For example, cuprotitanium (rutile withcopper added), ferrocarbon titanium (ilmenite reduced withcoke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced.[97]
About fifty grades oftitanium alloys are designed and currently used, although only a couple of dozen are readily available commercially.[98] TheASTM International recognizes 31 grades of titanium metal and alloys, of which grades one through four are commercially pure (unalloyed). Those four vary in 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 ductile (highest tensile strength with an oxygen content of 0.40%).[27] The remaining grades are alloys, each designed for specific properties of ductility, strength, hardness, electrical resistivity,creep resistance, specific corrosion resistance, and combinations thereof.[99]
In addition to the ASTM specifications, titanium 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.[100]
Forming and forging
Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account of the tendency of the metal tospringback. This is especially true of certain high-strength alloys.[101][102] Exposure to the oxygen in air at the elevated temperatures used in forging results in formation of a brittle oxygen-rich metallic surface layer called "alpha case" that worsens the fatigue properties, so it must be removed by milling, etching, or electrochemical treatment.[103] The working of titanium may includefriction welding,[104]cryo-forging,[105] andvacuum arc remelting.[106]
Applications
A titanium cylinder
Titanium is used in steel as an alloying element (ferro-titanium) to reducegrain size and as adeoxidizer, and in stainless steel to reduce carbon content.[11] Titanium is often alloyed with aluminium (to refine grain size),vanadium, copper (to harden),iron,manganese,molybdenum, and other metals.[107] Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used inpyrotechnics as a source of bright-burning particles.[108]
Titanium dioxide (TiO 2) is the most common compound of the element, being the end point of 95% of the world's refined titanium. It is a widely used whitepigment.[32] It is also used in cement, in gemstones, and as an optical opacifier in paper.[109]
TiO 2 pigment is chemically inert, resists fading in sunlight, and is very opaque: it imparts a pure and brilliant white color to the brown or grey chemicals that form the majority of household plastics.[13] In nature, this compound is found in the minerals anatase, brookite, and rutile.[11] Paint made with titanium dioxide does well in severe temperatures and marine environments.[13] Pure titanium dioxide has a very highindex of refraction and anoptical dispersion higher thandiamond.[12] Titanium dioxide is used insunscreens because it reflects and absorbsUV light.[19]
Aerospace and marine
TheLockheed A-12, one of the first planes with a frame mostly made of titanium
Because titanium alloys have hightensile strength to density ratio,[17] highcorrosion resistance,[12] fatigue resistance, high crack resistance,[110] and ability to withstand moderately high temperatures without creeping, they are used in aircraft, armor plating, naval ships, spacecraft, and missiles.[12][13] For these applications, titanium is alloyed with aluminium, zirconium, nickel,[111] vanadium, and other elements to manufacture a variety of components including critical structural parts,landing gear,firewalls, exhaust ducts (helicopters), and hydraulic systems. About two thirds of all titanium metal produced is used in aircraft frames and engines.[112] Thetitanium 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications.[113]
TheLockheed A-12 and theSR-71 "Blackbird" were two of the first aircraft frames where titanium was used, paving the way for much wider use in modern military and commercial aircraft. A large amount of titanium mill products are used in the production of many aircraft, such as (following values are amount of raw mill products used, only a fraction of this ends up in the finished aircraft): 116 metric tons are used in theBoeing 787, 77 in theAirbus A380, 59 in theBoeing 777, 45 in theBoeing 747, 32 in theAirbus A340, 18 in theBoeing 737, 18 in theAirbus A330, and 12 in theAirbus A320.[114] In aero engine applications, titanium is used for rotors, compressor blades, hydraulic system components, andnacelles.[115][116] An early use in jet engines was for theOrenda Iroquois in the 1950s.[117][118][119]
Because titanium is resistant to corrosion by sea water, it is used to make propeller shafts, rigging,heat exchangers indesalination plants,[12] heater-chillers for salt water aquariums, fishing line and leader, and divers' knives. Titanium is used in the housings and components of ocean-deployed surveillance and monitoring devices for science and military. The formerSoviet Union developed techniques for making submarines with hulls of titanium alloys,[120] forging titanium in huge vacuum tubes.[111]
Industrial
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 oil and gas downhole applications andnickelhydrometallurgy for their high strength (e. g.: titanium beta C alloy), corrosion resistance, or both. Thepulp and paper industry uses titanium in process equipment exposed to corrosive media, such assodium hypochlorite or wet chlorine gas (in the bleachery).[121] Titanium is also used insputtering targets.[122]
Powdered titanium acts as a non-evaporativegetter, and is one of several gas-reactive materials used to remove gases fromultra-high vacuum systems.[123] This application manifested intitanium sublimation pumps[124] first employed in 1961,[125] though the metal was first used in vacuum systems to prevent chambers from oxidizing in a design created byRaymond Herb in 1953.[126]
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. Titanium tetrachloride is also used to iridize glass and, because it fumes strongly in moist air, it is used to make smoke screens.[19] In many industrial applications, titanium and its alloys can serve as a potential substitute for other metals, such as nickel, niobium, scandium, silver, tantalum, and tungsten.[127]
Titanium metal is used in automotive applications, particularly in automobile and motorcycle racing where low weight and high strength and rigidity are critical.[128] The metal is generally too expensive for the general consumer market, though some late modelCorvettes have been manufactured with titanium exhausts.[129]
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 racing teams andadventure cyclists.[130] Titanium is used in spectable frames, as it is durable and protect the lenses, though it may be less flexible than alternatives.[131] Itsbiocompatibility is a potential benefit over other glasses frame materials.[132] Titanium is a common material for backpacking cookware and eating utensils. Titanium horseshoes are preferred to steel byfarriers because they are lighter and more durable.[133] Some upmarket lightweight and corrosion-resistant tools, such as shovels, knife handles and flashlights, are made of titanium or titanium alloys.[134]
Because of titanium's superior strength and light weight relative to other metals (steel, stainless steel, and aluminium), and because of advances in metalworking techniques, its use has become widespread in the manufacture of firearms. Primary uses include pistol frames and revolver cylinders. For the same reasons, it is used in the body of some laptop computers (for example, inApple'sPowerBook G4)[138][134] and phones (such as theiPhone 15 Pro).[139]
Jewelry
Relation between voltage and color for anodized titanium
Because of its durability, titanium is used in some designer jewelry, such astitanium rings.[133] Its inertness makes it hypoallergenic and wearable in environments such as swimming pools. Titanium is alsoalloyed with gold to produce an alloy that can be marketed as24-karat gold, because the 1% of alloyed Ti is insufficient to require a lesser mark. The resulting alloy is roughly the hardness of 14-karat gold and is more durable than pure 24-karat gold.[140]
Titanium's durability, light weight, and dent and corrosion resistance make it useful forwatch cases.[133] Some artists work with titanium to produce sculptures, decorative objects and furniture.[141] Titanium may beanodized to vary the thickness of the surface oxide layer, causing opticalinterference fringes and a variety of bright colors.[142] With its variable coloration and chemical inertness, titanium is a popular metal forbody piercing.[143]
Titanium has a minor use in dedicated non-circulating coins and medals. In 1999, the world's first titanium coin was minted forGibraltar's millennium celebration.[144] Pobjoy Mint, the British mint that produced the coin, continued to manufacture anodized titanium coins[145] until its closure in 2023.[146] TheGold Coast Titans, an Australian rugby league team, award a medal of pure titanium to their player of the year.[147]
Because titanium isbiocompatible (non-toxic and not rejected by the body), it has many medical uses, including surgical implements and implants, such as hip balls and sockets (joint replacement) anddental implants.[61] Titanium and titanium alloy implants have been used in surgery since the 1950s, and are favored due to their low rate of corrosion, long life, and lowYoung's modulus. A titanium alloy that contains 6% aluminium and 4% vanadium commonly used in the aerospace industry is also a common material for artificial joints.[148]
Medical screws and plate used to repair wrist fractures. Scale is in centimeters.
Titanium has the inherent ability toosseointegrate, enabling use indental implants that can last for over 30 years. This property is also useful fororthopedic implant applications.[61] These benefit from titanium's lower modulus of elasticity 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 andperiprosthetic 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.[149][150] Biomedical implants coated with a combination of silver and titanium have been researched as a potential option for load-bearing implants that need antimicrobial surfaces.[148]
Modern advancements in additive manufacturing techniques have increased potential for titanium use in orthopedic implant applications.[151] Complex implant scaffold designs can be 3D-printed using titanium alloys, which allows for more patient-specific applications and increased implant osseointegration.[152] Because titanium is non-ferromagnetic, patients with titanium implants can be safely examined withmagnetic resonance imaging (convenient for long-term implants). Preparing titanium for implantation in the body involves subjecting it to a high-temperatureplasma arc which removes the surface atoms, exposing fresh titanium that is instantly oxidized.[61] Titanium is used for thesurgical instruments used inimage-guided surgery, as well as wheelchairs, crutches, and any other products where high strength and low weight are desirable.[153]
Following the success ofplatinum-based chemotherapy, titanium(IV) complexes were among the first non-platinum compounds to be tested and accepted for clinical trials in cancer treatment.[155] The advantage of titanium compounds lies in their high efficacy and low toxicityin vivo. In biological environments, hydrolysis leads to the safe and inert titanium dioxide. Despite these advantages, the first candidate compounds failed clinical trials due to insufficient efficacy to toxicity ratios and formulation complications. Further development resulted in the creation of potentially effective, selective, and stable titanium-based drugs.[156]
Nuclear waste storage
Because of its corrosion resistance, containers made of titanium have been studied for the long-term storage of nuclear waste. Containers lasting more than 100,000 years are thought possible with manufacturing conditions that minimize material defects.[157] A titanium "drip shield" has been considered for installation over containers of other types to enhance their longevity.[158]
Titanium is non-toxic, even in large doses, and does not play any natural role inside thehuman body.[34] An estimated 0.8milligrams of titanium is ingested by humans each day, but most passes through thedigestive system without being absorbed in the tissues.[34] However, it can sometimesbioaccumulate in tissues that containsilica.Yellow nail syndrome has been reported in individuals that have been exposed to titanium, though the disorder's rarity have made it difficult to determine a direct association between exposure and disorder development.[161][162]
As a powder or in the form of metal shavings, titanium metal poses a significant fire hazard and, when heated inair, an explosion hazard.[163] Water andcarbon dioxide are ineffective for extinguishing a titanium fire;Class D dry powder agents must be used instead.[13] When used in the production or handling of chlorine, titanium exposed to dry chlorine gas may result in a titanium–chlorine fire.[164] Titanium can also catch fire when a fresh, non-oxidized surface comes in contact withliquid oxygen.[165]
Function in plants
Nettles contain up to 80 parts per million of titanium.[34]
An unknown mechanism inplants may use titanium to stimulate the production ofcarbohydrates and encourage growth. This may explain why most plants contain about 1part per million (ppm) of titanium, food plants have about 2 ppm, andhorsetail andnettle contain up to 80 ppm.[34]
^The thermal expansion isanisotropic: thecoefficients for each crystal axis are (at 20 °C): αa = 9.48×10−6/K, αc = 10.06×10−6/K, and αaverage = αV/3 = 9.68×10−6/K.
^Twenty-one radioisotopes were known as of 2021 with the publication of the NUBASE2020 nuclear data library,[37] with two more radioisotopes,65Ti and66Ti being discovered in 2025.[38]
^"Diesem zufolge will ich den Namen für die gegenwärtige metallische Substanz, gleichergestalt wie bei dem Uranium geschehen, aus der Mythologie, und zwar von den Ursöhnen der Erde, den Titanen, entlehnen, und benenne also diese neue Metallgeschlecht: Titanium; ... "[65](p 244) [By virtue of this I will derive the name for the present metallic substance — as happened similarly in the case of uranium — from mythology, namely from the first sons of the Earth, the Titans, and thus [I] name this new species of metal: "titanium"; ... ]
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^Ti(-2) is known inTi(CO)2−6; seeJohn E. Ellis (2006). "Adventures with Substances Containing Metals in Negative Oxidation States".Inorganic Chemistry.45 (8):3167–3186.doi:10.1021/ic052110i.
^Jilek, Robert E.; Tripepi, Giovanna; Urnezius, Eugenijus; Brennessel, William W.; Young, Victor G. Jr.; Ellis, John E. (2007). "Zerovalent titanium–sulfur complexes. Novel dithiocarbamato derivatives ofTi(CO)6:[Ti(CO)4(S2CNR2)]−".Chem. Commun. (25):2639–2641.doi:10.1039/B700808B.PMID17579764.
^Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references".Chinese Physics C.41 (3) 030003.doi:10.1088/1674-1137/41/3/030003.
^Liu, Gang; Huang, Wan-Xia; Yi, Yong (26 June 2013). "Preparation and Optical Storage Properties of λTi3O5 Powder".Journal of Inorganic Materials.28 (4):425–430.doi:10.3724/SP.J.1077.2013.12309 (inactive 1 July 2025).{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)
^Ramón, Diego J.; Yus, Miguel (2006). "In the arena of enantioselective synthesis, titanium complexes wear the laurel wreath".Chem. Rev.106 (6):2126–2308.doi:10.1021/cr040698p.PMID16771446.
^Gregor, William (1791). "Beobachtungen und Versuche über den Menakanit, einen in Cornwall gefundenen magnetischen Sand" [Observations and experiments regarding menaccanite [i.e., ilmenite], a magnetic sand found in Cornwall].Chemische Annalen (in German).1:pp. 40–54,103–119.
^Gregor, William (1791). "Sur le menakanite, espèce de sable attirable par l'aimant, trouvé dans la province de Cornouilles" [On menaccanite, a species of magnetic sand, found in the county of Cornwall].Observations et Mémoires sur la Physique (in French).39:72–78,152–160.
^Klaproth, Martin Heinrich (1795)."Chemische Untersuchung des sogenannten hungarischen rothen Schörls" [Chemical investigation of the so-called Hungarian red tourmaline [rutile]].Beiträge zur chemischen Kenntniss der Mineralkörper [Contributions to the chemical knowledge of mineral substances].1. Berlin, DE: Heinrich August Rottmann:233–244.
^"VSMPO stronger than ever"(PDF).Stainless Steel World. KCI Publishing B.V. July–August 2001. pp. 16–19. Archived fromthe original(PDF) on 5 October 2006. Retrieved2 January 2007.
^Jasper, Adam, ed. (2020).Architecture and Anthropology. Taylor & Francis. p. 42.ISBN978-1-351-10627-6.
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