Titanium

File:Titanium products.jpg

File:Titanium in water Pourbaix diagram.png for titanium in pure water, perchloric acid, or sodium hydroxidePuigdomenech, Ignasi (2004) [https://web.archive.org/web/20130605034847/http://www.kth.se/che/medusa Hydra/Medusa Chemical Equilibrium Database and Plotting Software], KTH Royal Institute of Technology.]]

Like aluminium and magnesium, the surface of titanium metal and its alloys oxidize immediately upon exposure to air to form a thin non-porous passivation layer that protects the bulk metal from further oxidation or corrosion. 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. This layer gives titanium excellent resistance to corrosion against oxidizing acids, but it will dissolve in dilute hydrofluoric acid, hot hydrochloric acid, and hot sulfuric acid.

Titanium is capable of withstanding attack by dilute sulfuric and hydrochloric acids at room temperature, chloride solutions, and most organic acids. However, titanium is corroded by concentrated acids.{{cite journal |author1=Casillas, N. |author2=Charlebois, S. |author3=Smyrl, W.H. |author4=White, H.S. |year=1994 |title=Pitting corrosion of titanium |journal=J. Electrochem. Soc. |volume=141 |issue=3 |pages=636–642 |doi=10.1149/1.2054783 |bibcode=1994JElS..141..636C |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a274980.pdf |url-status=live |archive-url=https://web.archive.org/web/20200827231129/https://apps.dtic.mil/dtic/tr/fulltext/u2/a274980.pdf |archive-date=27 August 2020}} Titanium is a very reactive metal that burns in normal air at lower temperatures than the melting point. Melting is possible only in an inert atmosphere or vacuum. At {{convert|550|°C|°F}}, it combines with chlorine. It also reacts with the other halogens and absorbs hydrogen.

Titanium readily reacts with oxygen at {{convert|1200|°C|°F}} in air, and at {{convert|610|°C|°F}} in pure oxygen, forming titanium dioxide. Titanium is one of the few elements that burns in pure nitrogen gas, reacting at {{convert|800|°C|°F}} to form titanium nitride, which causes embrittlement.{{cite book |title=Industrial Applications of Titanium and Zirconium|chapter-url= https://books.google.com/books?id=0Adr4zleybgC&pg=PA112 |page= 112|first= A.L. |last= Forrest |chapter= Effects of Metal Chemistry on Behavior of Titanium in Industrial Applications |year=1981}} Because of its high reactivity with oxygen, nitrogen, and many other gases, titanium that is evaporated from filaments is the basis for titanium sublimation pumps, in which titanium serves as a scavenger for these gases by chemically binding to them. Such pumps inexpensively produce extremely low pressures in ultra-high vacuum systems.

Titanium is the ninth-most abundant element in Earth's crust (0.63% by mass) and the seventh-most abundant metal. It is present as oxides in most igneous rocks, in sediments derived from them, in living things, and natural bodies of water.{{RubberBible86th}} Of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium. Its proportion in soils is approximately 0.5–1.5%.

Common titanium-containing minerals are anatase, brookite, ilmenite, perovskite, rutile, and titanite (sphene).{{harvnb|Emsley|2001|p=453}} Akaogiite is an extremely rare mineral consisting of titanium dioxide. 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 those minerals were mined in 2011, respectively. Significant titanium-bearing ilmenite deposits exist in Australia, Canada, China, India, Mozambique, New Zealand, Norway, Sierra Leone, South Africa, and Ukraine. About 210,000 tonnes of titanium metal sponge were produced in 2020, mostly in China (110,000 t), Japan (50,000 t), Russia (33,000 t) and Kazakhstan (15,000 t). Total reserves of anatase, ilmenite, and rutile are estimated to exceed 2 billion tonnes.

The concentration of titanium is about 4 picomolar 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.{{cite journal |doi= 10.1021/cr1002886 |pmid= 22074443 |title= Bioinorganic Chemistry of Titanium |journal= Chemical Reviews |volume= 112 |issue= 3 |pages= 1863–81 |year= 2012 |last1= Buettner |first1= K. M. |last2= Valentine |first2= A. M.}}

Titanium is contained in meteorites, and it has been detected in the Sun and in M-type stars (the coolest type) with a surface temperature of {{convert|3200|°C|°F}}.{{harvnb|Emsley|2001|p=451}} Rocks brought back from the Moon during the Apollo 17 mission are composed of 12.1% TiO₂. Native titanium (pure metallic) is very rare.[http://www.mindat.org/min-7339.html Titanium]. Mindat

{{Main|Isotopes of titanium}}

Naturally occurring titanium is composed of five stable isotopes: ⁴⁶Ti, ⁴⁷Ti, ⁴⁸Ti, ⁴⁹Ti, and ⁵⁰Ti, with ⁴⁸Ti being the most abundant (73.8% natural abundance). At least 21 radioisotopes have been characterized, the most stable of which are ⁴⁴Ti with a half-life of 63 years; ⁴⁵Ti, 184.8 minutes; ⁵¹Ti, 5.76 minutes; and ⁵²Ti, 1.7 minutes. All other radioactive isotopes have half-lives less than 33 seconds, with the majority less than half a second.

The isotopes of titanium range in atomic weight from {{val|39.002|ul=Da}} (³⁹Ti) to {{val|63.999|u=Da}} (⁶⁴Ti).{{AME2016 II|ref}} The primary decay mode for isotopes lighter than ⁴⁶Ti is positron emission (with the exception of ⁴⁴Ti which undergoes electron capture), leading to isotopes of scandium, and the primary mode for isotopes heavier than ⁵⁰Ti is beta emission, leading to isotopes of vanadium.

Titanium becomes radioactive upon bombardment with deuterons, emitting mainly positrons and hard gamma rays.

{{Category see also|Titanium compounds|Titanium minerals}}

{{see also|Titanium alloy}}

File:Titanium nitride coating.jpg]]

The +4 oxidation state dominates titanium chemistry,{{harvnb|Greenwood|Earnshaw|1997|p=958}} but compounds in the +3 oxidation state are also numerous.{{harvnb|Greenwood|Earnshaw|1997|p=970}} Commonly, titanium adopts an octahedral coordination geometry in its complexes,{{harvnb|Greenwood|Earnshaw|1997|p=960}}{{harvnb|Greenwood|Earnshaw|1997|p=967}} but tetrahedral TiCl₄ is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.

The most important oxide is TiO₂, which exists in three important polymorphs; anatase, brookite, and rutile. All three are white diamagnetic solids, although mineral samples can appear dark (see rutile). They adopt polymeric structures in which Ti is surrounded by six oxide ligands that link to other Ti centers.{{harvnb|Greenwood|Earnshaw|1997|p=961}}

The term titanates usually refers to titanium(IV) compounds, as represented by barium titanate (BaTiO₃). With a perovskite structure, this material exhibits piezoelectric properties and is used as a transducer in the interconversion of sound and electricity. Many minerals are titanates, such as ilmenite (FeTiO₃). Star sapphires and rubies get their asterism (star-forming shine) from the presence of titanium dioxide impurities.

A variety of reduced oxides (suboxides) of titanium are known, mainly reduced stoichiometries of titanium dioxide obtained by atmospheric plasma spraying. Ti₃O₅, described as a Ti(IV)-Ti(III) species, is a purple semiconductor produced by reduction of TiO₂ with hydrogen at high temperatures,{{cite journal |last1=Liu |first1=Gang |last2=Huang |first2=Wan-Xia |last3=Yi |first3=Yong |title=Preparation and Optical Storage Properties of λTi₃O₅ Powder |journal=Journal of Inorganic Materials |date=26 June 2013 |volume=28 |issue=4 |pages=425–430|doi=10.3724/SP.J.1077.2013.12309|doi-broken-date=1 November 2024 }} 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.{{cite journal |last1=Bonardi |first1=Antonio |last2=Pühlhofer |first2=Gerd |last3=Hermanutz |first3=Stephan |last4=Santangelo |first4=Andrea |year=2014 |title=A new solution for mirror coating in {{mvar|γ}}-ray Cherenkov Astronomy |journal=Experimental Astronomy |volume=38 |issue=1–2 |pages=1–9 |doi=10.1007/s10686-014-9398-x |bibcode=2014ExA....38....1B |s2cid=119213226 |arxiv=1406.0622}} Also known is Ti₂O₃, with the corundum structure, and TiO, with the rock salt structure, although often nonstoichiometric.{{sfn|Greenwood|Earnshaw|1997|p=962}}

The alkoxides of titanium(IV), prepared by treating TiCl₄ with alcohols, are colorless compounds that convert to the dioxide on reaction with water. They are industrially useful for depositing solid TiO₂ via the sol-gel process. Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation.{{cite journal |author1=Ramón, Diego J. |author2=Yus, Miguel |year=2006 |title=In the arena of enantioselective synthesis, titanium complexes wear the laurel wreath |journal=Chem. Rev. |volume=106 |issue=6 |pages=2126–2308 |doi=10.1021/cr040698p |pmid=16771446}}

Titanium forms a variety of sulfides, but only TiS₂ has attracted significant interest. It adopts a layered structure and was used as a cathode in the development of lithium batteries. Because Ti(IV) is a "hard cation", the sulfides of titanium are unstable and tend to hydrolyze to the oxide with release of hydrogen sulfide.{{cite book | last1 = McKelvy | first1 = M.J. | last2 = Glaunsinger | first2 = W.S. | year = 1995 | title = Inorganic Syntheses | chapter = Titanium Disulfide | volume = 30 | pages = 28–32 | doi = 10.1002/9780470132616.ch7 | isbn = 978-0-470-13261-6 }}

Titanium nitride (TiN) is a refractory solid exhibiting extreme hardness, thermal/electrical conductivity, and a high melting point.{{Cite journal |last=Saha |first=Naresh |year=1992 |title=Titanium nitride oxidation chemistry: An x-ray photoelectron spectroscopy study |journal=Journal of Applied Physics |volume=72 |issue=7 |pages=3072–3079 |doi=10.1063/1.351465 |bibcode=1992JAP....72.3072S}} TiN has a hardness equivalent to sapphire and carborundum (9.0 on the Mohs scale),{{cite web |author=Schubert, E.F. |title=The hardness scale introduced by Friederich Mohs |series=Educational resources |publisher=Rensselaer Polytechnic Institute |place=Troy, NY |url=https://www.ecse.rpi.edu/~schubert/Educational-resources/Materials-Hardness.pdf |url-status=live |archive-url=https://web.archive.org/web/20100603075632/http://www.rpi.edu/~schubert/Educational-resources/Materials-Hardness.pdf |archive-date=3 June 2010}} and is often used to coat cutting tools, such as drill bits.{{cite magazine |last=Truini |first=Joseph |date=May 1988 |title=Drill bits |magazine=Popular Mechanics |volume=165 |issue=5 |page=91 |issn=0032-4558 |url=https://books.google.com/books?id=Z-QDAAAAMBAJ}} It is also used as a gold-colored decorative finish and as a barrier layer in semiconductor fabrication.{{cite book|last=Baliga |first=B. Jayant |year=2005 |title=Silicon carbide power devices |publisher=World Scientific |page=91 |isbn=978-981-256-605-8 |url=https://books.google.com/books?id=LNLVwAzhN7EC}} Titanium carbide (TiC), which is also very hard, is found in cutting tools and coatings.{{cite web |title=Titanium carbide product information |publisher=H.C. Starck |url=http://www.hcstarck.com/titanium_carbide_tic |access-date=16 November 2015 |archive-url=https://web.archive.org/web/20170922194330/https://www.hcstarck.com/titanium_carbide_tic |archive-date=22 September 2017}}

File:TiCl3.jpg.]]

Titanium tetrachloride (titanium(IV) chloride, TiCl₄{{cite report |author1=Seong, S. |author2=Younossi, O. |author3=Goldsmith, B.W. |year=2009 |title=Titanium: Industrial base, price trends, and technology initiatives |publisher=Rand Corporation |isbn=978-0-8330-4575-1 |page=10 |url=https://books.google.com/books?id=tIPFfYW304IC&pg=PA10}}) is a colorless volatile liquid (commercial samples are yellowish) that, in air, hydrolyzes with spectacular emission of white clouds. Via the Kroll 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.{{cite book |last=Johnson |first=Richard W. |year=1998 |title=The Handbook of Fluid Dynamics |publisher=Springer |pages=38–21 |isbn=978-3-540-64612-9 |url=https://books.google.com/books?id=JBTlucgGdegC}} It is widely used in organic chemistry as a Lewis acid, for example in the Mukaiyama aldol condensation.{{cite book |last=Coates |first=Robert M. |author2=Paquette, Leo A. |year=2000 |title=Handbook of Reagents for Organic Synthesis |publisher=John Wiley and Sons |page=93|isbn=978-0-470-85625-3|url=https://books.google.com/books?id=xxYjJgupBSMC}} In the van Arkel–de Boer process, titanium tetraiodide (TiI₄) is generated in the production of high purity titanium metal.{{harvnb|Greenwood|Earnshaw|1997|p=965}}

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.{{cite encyclopedia |first1=Lise-Lotte |last1=Gundersen |first2=Frode |last2=Rise |first3=Kjell |last3=Undheim |first4=José |last4=Méndez Andino |year=2007 |title=Titanium(III) Chloride |encyclopedia=Encyclopedia of Reagents for Organic Synthesis |doi=10.1002/047084289X.rt120.pub2 |isbn=978-0-471-93623-7 }}

{{Main|Organotitanium chemistry}}

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. (C₅H₅)₂Ti(CO)₂.{{cite book |author-link=John F. Hartwig |author=Hartwig, J.F. |year=2010 |title=Organotransition Metal Chemistry, from Bonding to Catalysis |publisher=University Science Books |place=New York, NY |isbn=978-1-891389-53-5}}

Following the success of platinum-based chemotherapy, titanium(IV) complexes were among the first non-platinum compounds to be tested for cancer treatment. The advantage of titanium compounds lies in their high efficacy and low toxicity in 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.{{cite book |last1=Tshuva |first1=Edit Y. |last2=Miller |first2=Maya |editor1-last=Sigel |editor1-first=Astrid |editor2-last=Sigel |editor2-first=Helmut|editor3-last=Freisinger |editor3-first=Eva |editor4-last=Sigel |editor4-first=Roland K.O. |year=2018 |title=Metallo-drugs: Development and action of anticancer agents |series=Metal Ions in Life Sciences |volume=18 |doi=10.1515/9783110470734-014 |pmid=29394027 |publisher=de Gruyter GmbH |location=Berlin, DE |chapter=Chapter 8. Coordination complexes of titanium(IV) for anticancer therapy |pages=219–250 |isbn=978-3-11-047073-4 |chapter-url=https://books.google.com/books?id=4nBLDwAAQBAJ}}

File:Martin Heinrich Klaproth.jpg named titanium for the Titans of Greek mythology.]]

Titanium was discovered in 1791 by the clergyman and geologist William Gregor as an inclusion of a mineral in Cornwall, Great Britain. Gregor recognized the presence of a new element in ilmenite when he found black sand by a stream and noticed the sand was attracted by a magnet. 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.{{harvnb|Barksdale|1968|p=732}} 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 and Observations et Mémoires sur la Physique.{{cite journal |author=Gregor, William |year=1791 |title=Beobachtungen und Versuche über den Menakanit, einen in Cornwall gefundenen magnetischen Sand |lang=de |trans-title=Observations and experiments regarding menaccanite [i.e., ilmenite], a magnetic sand found in Cornwall |journal=Chemische Annalen |volume=1 |pages=[https://books.google.com/books?id=ZFAyAQAAMAAJ&pg=PA40 pp. 40–54], [https://books.google.com/books?id=ZFAyAQAAMAAJ&pg=PA103 103–119]}}{{cite journal |author=Gregor, William |year=1791 |title=Sur le menakanite, espèce de sable attirable par l'aimant, trouvé dans la province de Cornouilles |trans-title=On menaccanite, a species of magnetic sand, found in the county of Cornwall |lang=fr |journal=Observations et Mémoires sur la Physique |volume=39 |pages=[https://archive.org/stream/journaldephysiq23unkngoog#page/n77/mode/1up 72–78], [https://archive.org/stream/journaldephysiq23unkngoog#page/n159/mode/1up 152–160]}} He named this oxide manaccanite.{{cite journal |last1=Habashi |first1=Fathi |title=Historical Introduction to Refractory Metals |journal=Mineral Processing and Extractive Metallurgy Review |date=January 2001 |volume=22 |issue=1 |pages=25–53 |doi=10.1080/08827509808962488|bibcode=2001MPEMR..22...25H |s2cid=100370649 }}

Around the same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it. The oxide was independently rediscovered in 1795 by Prussian chemist Martin Heinrich Klaproth in rutile from Boinik (the German name of Bajmócska), a village in Hungary (now Bojničky in Slovakia).{{efn|

"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; ... "{{cite journal |author=Klaproth, Martin Heinrich |year=1795 |url=https://books.google.com/books?id=5zFGAAAAYAAJ&pg=PA233 |title=Chemische Untersuchung des sogenannten hungarischen rothen Schörls |trans-title=Chemical investigation of the so-called Hungarian red tourmaline [rutile] |journal=Beiträge zur chemischen Kenntniss der Mineralkörper [Contributions to the chemical knowledge of mineral substances] |volume=1 |pages=233–244 |place=Berlin, DE |publisher=Heinrich August Rottmann}}{{rp|style=ama|p= 244}}

{{br}}

[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"; ... ]

}}

Klaproth found that it contained a new element and named it for the Titans of Greek mythology. After hearing about Gregor's earlier discovery, he obtained a sample of manaccanite and confirmed that it contained titanium.{{cite report |title=Twenty-five years of Titanium news: A concise and timely report on titanium and titanium recycling |year=1995 |publisher=Suisman Titanium Corporation |via=Pennsylvania State University / Google Books |page=37 |url=https://books.google.com/books?id=amIQAQAAMAAJ}}

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 with carbon (as in iron smelting) because titanium combines with the carbon to produce titanium carbide. An extraction of 95% pure titanium was achieved by Lars Fredrik Nilson and Otto 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.{{Citation |last1=Takeda |first1=Osamu |title=Chapter 2.7 - Rare Earth, Titanium Group Metals, and Reactive Metals Production |date=2024-01-01 |work=Treatise on Process Metallurgy (Second Edition) |pages=697–750 |editor-last=Seetharaman |editor-first=Seshadri |url=https://www.sciencedirect.com/science/article/abs/pii/B9780323853736000107 |access-date=2024-11-22 |publisher=Elsevier |isbn=978-0-323-85373-6 |last2=Uda |first2=Tetsuya |last3=Okabe |first3=Toru H. |editor2-last=Guthrie |editor2-first=Roderick |editor3-last=McLean |editor3-first=Alexander |editor4-last=Seetharaman |editor4-first=Sridhar |doi=10.1016/B978-0-323-85373-6.00010-7}} Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl₄ with sodium at {{convert|700-800|°C|°F}} under great pressure{{harvnb|Roza|2008|p=9}} in a batch process known as the Hunter process. Titanium metal was not used outside the laboratory until 1932 when William Justin Kroll produced it by reducing titanium tetrachloride (TiCl₄) with calcium.{{harvnb|Greenwood|Earnshaw|1997|p=955}} Eight years later he refined this process with magnesium and with sodium in what became known as the Kroll process. Although research continues to seek cheaper and more efficient routes, such as the FFC Cambridge process, the Kroll process is still predominantly used for commercial production.

File:Titanium metal.jpg]]

Titanium of very high purity was made in small quantities when Anton Eduard van Arkel and Jan 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.{{cite journal |author1=van Arkel, A.E. |author1-link=Anton Eduard van Arkel |author2=de Boer, J.H. |year=1925 |title=Preparation of pure titanium, zirconium, hafnium, and thorium metal |journal=Zeitschrift für anorganische und allgemeine Chemie |volume=148 |pages=345–50 |doi=10.1002/zaac.19251480133}}

In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications (Alfa class and Mike class){{cite web |last=Yanko |first=Eugene |year=2006 |title=Submarines: General information |publisher=Omsk VTTV Arms Exhibition and Military Parade JSC |url=http://warfare.be/db/catid/243/linkid/1756/ |access-date=2 February 2015 |archive-url=https://web.archive.org/web/20160406114504/http://warfare.be/db/catid/243/linkid/1756/ |archive-date=6 April 2016 }} as part of programs related to the Cold War.{{cite news |title=VSMPO stronger than ever |date=July–August 2001 |website=Stainless Steel World |pages=16–19 |publisher=KCI Publishing B.V. |url=http://www.stainless-steel-world.net/pdf/ssw0107.pdf?issueID=30 |access-date=2 January 2007 |archive-date=5 October 2006 |archive-url=https://web.archive.org/web/20061005041506/http://www.stainless-steel-world.net/pdf/ssw0107.pdf?issueID=30 }} Starting in the early 1950s, titanium came into use extensively in military aviation, particularly in high-performance jets, starting with aircraft such as the F-100 Super Sabre and Lockheed A-12 and SR-71.{{cite book |editor=Jasper, Adam |year=2020 |title=Architecture and Anthropology |isbn=978-1-351-10627-6 |publisher=Taylor & Francis |page=42}}

Throughout the Cold War period, titanium was considered a strategic material by the U.S. government, and a large stockpile of titanium sponge (a porous form of the pure metal) was maintained by the Defense National Stockpile Center, until the stockpile was dispersed in the 2000s.{{cite report |title=Strategic and Critical Materials Report to the Congress. Operations under the Strategic and Critical Materials Stock Piling Act during the Period October 2007 through September 2008 |year=2008 |publisher=United States Department of Defense |page=3304 |author=Defense National Stockpile Center |url=https://www.dnsc.dla.mil/Uploads/Materials/esolomon_5-21-2009_13-29-4_2008OpsReport.pdf |author-link=Defense National Stockpile Center |archive-url=https://web.archive.org/web/20100211093359/https://www.dnsc.dla.mil/Uploads/Materials/esolomon_5-21-2009_13-29-4_2008OpsReport.pdf |archive-date=11 February 2010 }} As of 2021, the four leading producers of titanium sponge were China (52%), Japan (24%), Russia (16%) and Kazakhstan (7%).

{{Main|Titanium production by country}}

File:TitaniumUSGOV.jpg

• The Becher process is an industrial process used to produce synthetic rutile, a form of titanium dioxide, from the ore ilmenite.
• The Chloride process.
• The Sulfate process: "relies on sulfuric acid (H2SO4) to leach titanium from ilmenite ore (FeTiO3). The resulting reaction produces titanyl sulfate (TiOSO4). A secondary hydrolysis stage is used to break the titanyl sulfate into hydrated TiO2 and H2SO4. Finally, heat is used to remove the water and create the end product - pure TiO2."{{cite news |url=https://www.barbenanalytical.com/-/media/ametekbarbenanalytical/downloads/application_notes/tio2_an_reva.pdf?la=en&revision=eee43ea5-f5e3-4167-af19-4c177cc3dcdd |title=Application Note Titanium Dioxide - Sulfate Process |publisher=Ametek |agency=Barben Analytical |date=2015}}

{{see also|Category:Titanium processes}}

{{also|Category:Titanium companies}}

The Hunter process was the first industrial process to produce pure metallic titanium. It was invented in 1910 by Matthew A. Hunter, a chemist born in New Zealand who worked in the United States.{{cite journal | last1 = Hunter | first1 = M. A. | year = 1910| title = Metallic Titanium | url = | journal = J. Am. Chem. Soc. | volume = 32| issue = | pages = 330–336| doi = 10.1021/ja01921a006 }} The process involves reducing titanium tetrachloride (TiCl₄) with sodium (Na) in a batch reactor with an inert atmosphere at a temperature of 1,000 °C. Dilute hydrochloric acid is then used to leach the salt from the product.{{Cite encyclopedia |entry=Hunter process |dictionary=A Dictionary of Chemical Engineering |date=2014 |url=http://www.oxfordreference.com/view/10.1093/acref/9780199651450.001.0001/acref-9780199651450-e-1447 |url-access=subscription |language=en|doi=10.1093/acref/9780199651450.001.0001|last1=Schaschke |first1=Carl |publisher=Oxford University Press |isbn=978-0-19-965145-0 }}

:TiCl₄(g) + 4 Na(l) → 4 NaCl(l) + Ti(s)

File:Sample of Titanium tetrachloride 01.jpg

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 as billet, bar, plate, sheet, strip, and tube; and secondary fabrication of finished shapes from mill products.{{harvnb|Donachie|1988|loc=Ch. 4}}

Because it cannot be readily produced by reduction of titanium dioxide, titanium metal is obtained by reduction of titanium 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,{{harvnb|Barksdale|1968|p=733}} despite the Kroll process being less expensive than the Hunter process. To produce the TiCl₄ required by the Kroll process, the dioxide is subjected to carbothermic reduction in the presence of chlorine. 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 by fractional distillation, the TiCl₄ is reduced with {{convert|800|C}} molten magnesium in an argon atmosphere.

:2FeTiO3 + 7Cl2 + 6C ->[900^oC] 2FeCl3 + 2TiCl4 + 6CO

:TiCl4 + 2Mg ->[1100^oC] Ti + 2MgCl2

The van Arkel–de Boer process was the first semi-industrial process for pure Titanium. It involves thermal decomposition of titanium tetraiodide.

Titanium powder is manufactured using a flow production process known as the Armstrong process{{harvnb|Roza|2008|p=25}} that is similar to the batch production Hunter process. A stream of titanium tetrachloride gas is added to a stream of molten sodium; the products (sodium chloride salt and titanium particles) is filtered from the extra sodium. Titanium is then separated from the salt by water washing. Both sodium and chlorine are recycled to produce and process more titanium tetrachloride.{{cite web |title=Titanium |date=15 January 2015 |website=The Essential Chemical Industry online |series=CIEC Promoting Science |publisher=University of York |location=York, UK |url=http://www.essentialchemicalindustry.org/metals/titanium.html}}

Methods for electrolytic production of Ti metal from {{chem2|TiO2}} using molten salt electrolytes have been researched and tested at laboratory and small pilot plant scales. The lead author of an impartial review published in 2017 considered his own process "ready for scaling up."{{cite journal |last1=Fray |first1=Derek |last2=Schwandt |first2=Carsten |title=Aspects of the Application of Electrochemistry to the Extraction of Titanium and Its Applications |journal=Materials Transactions |volume=58 |date=2017 |issue=3 |issn=1345-9678 |doi=10.2320/matertrans.MK201619 |pages=306–312}} A 2023 review "discusses the electrochemical principles involved in the recovery of metals from aqueous solutions and fused salt electrolytes", with particular attention paid to titanium. While some metals such as nickel and copper can be refined by electrowinning at room temperature, titanium must be in the molten state and "there is a strong chance of attack of the refractory lining by molten titanium."{{cite journal |doi=10.1080/25726641.2023.2255368 |title=Role of electrochemical processes in the extraction of metals and alloys – a review |date=2023 |last1=Shamsuddin |first1=Mohammad |last2=Sohn |first2=Hong Yong |journal=Mineral Processing and Extractive Metallurgy: Transactions of the Institutions of Mining and Metallurgy |volume=132 |issue=3–4 |pages=193–209 |bibcode=2023MPEM..132..193S }} Zhang et al concluded their Perspective on Thermochemical and Electrochemical Processes for Titanium Metal Production in 2017 that "Even though there are strong interests in the industry for finding a better method to produce Ti metal, and a large number of new concepts and improvements have been investigated at the laboratory or even at pilot plant scales, there is no new process to date that can replace the Kroll process commercially."{{cite journal |title=A Perspective on Thermochemical and Electrochemical Processes for Titanium Metal Production |date=2017 |doi=10.1007/s11837-017-2481-9 |last1=Zhang |first1=Ying |last2=Fang |first2=Zhigang Zak |last3=Sun |first3=Pei |last4=Zheng |first4=Shili |last5=Xia |first5=Yang |last6=Free |first6=Michael |journal=JOM |volume=69 |issue=10 |pages=1861–1868 |bibcode=2017JOM....69j1861Z }}

The Hydrogen assisted magnesiothermic reduction (HAMR) process uses titanium dihydride.

File:Evolution Ti.jpg

All welding of titanium must be done in an inert atmosphere of argon or helium to shield it from contamination with atmospheric gases (oxygen, nitrogen, and hydrogen). Contamination causes a variety of conditions, such as embrittlement, which reduce the integrity of the assembly welds and lead to joint failure.{{Cite book |year=1955 |title=Arc-welding Titanium |author1= Engel, Abraham L. |author2=Huber, R.W. |author3=Lane, I.R. |publisher=U.S. Department of the Interior, Bureau of Mines }}

Titanium is very difficult to solder directly, and hence a solderable metal or alloy such as steel is coated on titanium prior to soldering.{{cite book | title=Report on Brazing and Soldering of Titanium |year=1956 |publisher=Titanium Metallurgical Laboratory, Battelle Memorial Institute |author1=Lewis, W.J. |author2=Faulkner, G.E. |author3=Rieppel, P.J. | url=https://books.google.com/books?id=316b7CW_HOMC&dq=Titanium+soldering&pg=PA2}} Titanium metal can be machined with the same equipment and the same processes as stainless steel.

{{main|Titanium alloys}}

File:Titanium products.jpg

Common titanium alloys are made by reduction. For example, cuprotitanium (rutile with copper added), ferrocarbon titanium (ilmenite reduced with coke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced.{{cite encyclopedia |title=Titanium |year=2005 |encyclopedia=Microsoft Encarta |url=http://encarta.msn.com/encyclopedia_761569280/Titanium.html |access-date=29 December 2006 |archive-url= https://web.archive.org/web/20061027112633/http://encarta.msn.com/encyclopedia_761569280/Titanium.html |archive-date=27 October 2006}}

About fifty grades of titanium alloys are designed and currently used, although only a couple of dozen are readily available commercially.{{harvnb|Donachie|1988|p=16, Appendix J}} The ASTM 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%). The remaining grades are alloys, each designed for specific properties of ductility, strength, hardness, electrical resistivity, creep resistance, specific corrosion resistance, and combinations thereof.{{cite book |title=Annual Book of ASTM Standards |section=Volume 02.04: Non-ferrous Metals |year=2006 |publisher=ASTM International |location=West Conshohocken, PA |at=section 2 |isbn=978-0-8031-4086-8 |url=https://books.google.com/books?id=yCGIPQAACAAJ}} {{cite book |title=Annual Book of ASTM Standards |year=1998 |section=Volume 13.01: Medical Devices; Emergency Medical Services |publisher=ASTM International |location=West Conshohocken, PA |at=sections 2 & 13 |isbn=978-0-8031-2452-3}}

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.{{harvnb|Donachie|1988|pp=13–16, Appendices H and J}}

Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account of the tendency of the metal to springback. This is especially true of certain high-strength alloys.{{cite book|title=AWS G2.4/G2.4M:2007 Guide for the Fusion Welding of Titanium and Titanium Alloys |year=2006 |publisher=American Welding Society |place=Miami |url=http://pdfcast.org/pdf/titanium-design-and-fabrication-handbook-for-industrial-applications |archive-url=https://web.archive.org/web/20101210022045/http://pdfcast.org/pdf/titanium-design-and-fabrication-handbook-for-industrial-applications |archive-date=10 December 2010 }}{{cite book|title=Titanium design and fabrication handbook for industrial applications |year=1997 |publisher=Titanium Metals Corporation |location=Dallas |url=http://www.timet.com/design%26fabframe.html |author-link=Titanium Metals Corporation |archive-url=https://web.archive.org/web/20090209014255/http://www.timet.com/design%26fabframe.html |archive-date=9 February 2009 }} 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.{{cite journal |last1=Chen |first1=George Z. |last2=Fray |first2=Derek J. |last3=Farthing |first3=Tom W. |year=2001 |title=Cathodic deoxygenation of the alpha case on titanium and alloys in molten calcium chloride |journal=Metall. Mater. Trans. B |volume=32 |issue=6 |pages=1041–1052 |doi=10.1007/s11663-001-0093-8 |bibcode=2001MMTB...32.1041C |s2cid=95616531 |url=https://link.springer.com/article/10.1007/s11663-001-0093-8}} The working of titanium is very complicated,{{cite news |url=https://www.totalmateria.com/en-us/articles/fabrication-of-titanium-and-titanium-alloys/ |title=Fabrication of Titanium and Titanium Alloys | Total Materia }}{{cite news |url=https://www.titaniuminfogroup.com/forging-process-of-titanium-alloy.html |title=Forging process of Titanium alloy |publisher=Titanium Info Group |date=2020-07-24}}{{cite news |url=https://www.aubertduval.com/wp-media/uploads/2021/06/brochure-titane_2021.pdf |title=TITANIUM FOR DEMANDING MARKETS from ingots to finished parts |date=June 2021 |publisher=Aubert & Duval}} and may include Friction welding,{{cite news |url=https://blog.mtiwelding.com/linear-friction-welding-for-titanium-forgings |title=Linear Friction Welding: A Solution for Titanium Forgings }} cryo-forging,{{cite news |url=https://www.machinedesign.com/materials/article/21179098/ultra-cold-forging-makes-titanium-strong-and-ductile |title=Ultra-Cold Forging Makes Titanium Strong and Ductile |date=21 October 2021 }} and Vacuum arc remelting.

File:Titanzylinder.jpg

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. Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron, manganese, molybdenum, and other metals.{{cite book |last=Hampel |first=Clifford A. |year=1968 |title=The Encyclopedia of the Chemical Elements |page=738 |publisher=Van Nostrand Reinhold |isbn=978-0-442-15598-8}} Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright-burning particles.{{cite book |author1=Mocella, Chris |author2=Conkling, John A. |year=2019 |title=Chemistry of Pyrotechnics|publisher=CRC Press |page=86 |isbn=978-1-351-62656-9}}

File:Titanium(IV) oxide.jpg is the most commonly used compound of titanium.]]

About 95% of all titanium ore is destined for refinement into titanium dioxide ({{chem|TiO|2}}), an intensely white permanent pigment used in paints, paper, toothpaste, and plastics.{{cite web |title=Titanium |publisher=United States Geological Survey (USGS) |website=USGS Minerals Information |url=http://minerals.usgs.gov/minerals/pubs/commodity/titanium/}} It is also used in cement, in gemstones, and as an optical opacifier in paper.{{cite book |last=Smook |first=Gary A. |year=2002 |title=Handbook for Pulp & Paper Technologists |edition=3rd |publisher=Angus Wilde Publications |isbn=978-0-9694628-5-9 |page=223 |url=https://books.google.com/books?id=TgtFPgAACAAJ}}

{{chem|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. In nature, this compound is found in the minerals anatase, brookite, and rutile. Paint made with titanium dioxide does well in severe temperatures and marine environments. Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond. Titanium dioxide is used in sunscreens because it reflects and absorbs UV light.

File:A12-flying.jpg, first plane made of 93% titanium]]

Because titanium alloys have high tensile strength to density ratio, high corrosion resistance, fatigue resistance, high crack resistance,{{cite book |last=Moiseyev |first=Valentin N. |year=2006 |title=Titanium Alloys: Russian Aircraft and Aerospace Applications |publisher=Taylor and Francis, LLC |page=196 |isbn=978-0-8493-3273-9 |url=https://books.google.com/books?id=legtmQEACAAJ}} and ability to withstand moderately high temperatures without creeping, they are used in aircraft, armor plating, naval ships, spacecraft, and missiles. For these applications, titanium is alloyed with aluminium, zirconium, nickel, vanadium, and other elements to manufacture a variety of components including critical structural parts, landing gear, firewalls, exhaust ducts (helicopters), and hydraulic systems. In fact, about two thirds of all titanium metal produced is used in aircraft engines and frames. The titanium 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications.{{harvnb|Donachie|1988|p=13}}

The Lockheed A-12 and the SR-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 the Boeing 787, 77 in the Airbus A380, 59 in the Boeing 777, 45 in the Boeing 747, 32 in the Airbus A340, 18 in the Boeing 737, 18 in the Airbus A330, and 12 in the Airbus A320.{{cite book |editor=Froes, F.H. |year=2015 |title=Titanium Physical Metallurgy, Processing, and Applications |page=7 |isbn=978-1-62708-080-4 |publisher=ASM International }} In aero engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles.{{Cite web |date=2024-04-10 |title=Titanium in Aerospace – Titanium |url=https://titaniumthemetal.org/blog/titanium-in-aerospace/ |access-date=2024-05-08 |language=en}}{{Cite web |title=Titanium Metal (Ti) / Sponge / Titanium Powder |url=https://www.lb7.uscourts.gov/documents/13cr5152.pdf |access-date=May 8, 2024 |website=www.lb7.uscourts.gov}} An early use in jet engines was for the Orenda Iroquois in the 1950s.{{bcn|date=January 2022}}{{cite web |title=Iroquois |year=1957 |website=Flight Global (archive) |page=412 |url=https://www.flightglobal.com/pdfarchive/view/1957/1957%20-%201324.html |archive-url=https://web.archive.org/web/20091213041629/https://www.flightglobal.com/pdfarchive/view/1957/1957%20-%201324.html |archive-date=13 December 2009 }}

Because titanium is resistant to corrosion by sea water, it is used to make propeller shafts, rigging, heat exchangers in desalination plants, 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 former Soviet Union developed techniques for making submarines with hulls of titanium alloys,{{Cite web |date=2007 |title=Unravelling a Cold War Mystery |url=https://www.cia.gov/resources/csi/static/the-ALFA-SSN.pdf |access-date=May 8, 2024 |website=CIA}} forging titanium in huge vacuum tubes.{{cite news |author=Kramer, Andrew E. |date=5 July 2013 |title=Titanium Fills Vital Role for Boeing and Russia |newspaper=The New York Times |url=https://www.nytimes.com/2013/07/06/business/global/titanium-fills-vital-role-for-boeing-and-russia.html |access-date=6 July 2013}}

File:Titanium-stamps.jpg]]

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 and nickel hydrometallurgy for their high strength (e. g.: titanium beta C alloy), corrosion resistance, or 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).{{harvnb|Donachie|1988|pp=11–16}} Other applications include ultrasonic welding, wave soldering,{{cite book |title= Industrial Application of Titanium and Zirconium |publisher=ASTM International |editor= Kleefisch, E.W. |isbn= 978-0-8031-0745-8 |location= West Conshohocken, PA |year=1981 |url=https://books.google.com/books?id=cX2HK0osYA4C}} and sputtering targets.{{cite book |title=Handbook of Hard Coatings |publisher=William Andrew Inc. |chapter=chapter 8 |editor=Bunshah, Rointan F. |isbn=978-0-8155-1438-1 |location=Norwich, NY |chapter-url=https://books.google.com/books?id=daamnz8el2sC&pg=PA413 |year=2001}}

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.

File:Tweeter with Titanium membrane of loudspeaker box JBL TI 5000, 1990s.jpg loudspeaker driver with a membrane with 25 mm diameter made from titanium; from a JBL TI 5000 loudspeaker box, {{circa|1997}}]]

Titanium metal is used in automotive applications, particularly in automobile and motorcycle racing where low weight and high strength and rigidity are critical.{{cite conference |author=Funatani, K. |date=9–12 October 2000 |title=Recent trends in surface modification of light metals § Metal matrix composite technologies |publication-date=2001 |conference=20th ASM Heat Treating Society Conference |book-title=Heat Treating, an International ... Symposium on Residual Stresses in the Heat Treatment Industry |editor1=Funatani, Kiyoshi |editor2=Totten, George E. |place=St. Louis, MO |publisher=ASM International |volume=1 & 2 |pages=138–144, esp. 141 |isbn=978-0-87170-727-7 |url=https://books.google.com/books?id=4F1zYT4FHyMC}}{{rp|style=ama|p= 141}} The metal is generally too expensive for the general consumer market, though some late model Corvettes have been manufactured with titanium exhausts,{{cite web |title=Titanium exhausts |publisher=National Corvette Museum |year=2006 |url=http://www.iglou.com/corvette/specs/2001/exhaust.htm |access-date=26 December 2006 |archive-url=https://archive.today/20130103075117/http://www.iglou.com/corvette/specs/2001/exhaust.htm |archive-date=3 January 2013}} and a Corvette Z06's LT4 supercharged engine uses lightweight, solid titanium intake valves for greater strength and resistance to heat.{{cite press release |title=Compact powerhouse: Inside Corvette Z06's LT4 engine 650-hp supercharged 6.2L V-8 makes world-class power in more efficient package |date=20 August 2014 |publisher=General Motors |website=media.gm.com |url=http://media.gm.com/media/us/en/chevrolet/vehicles/corvette-z06/2015.detail.html/content/Pages/news/us/en/2014/Aug/0820-8speed/0820-compact-powerhouse.html}}

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 and adventure cyclists.{{cite book |last=Davis |first=Joseph R. |year=1998 |title=Metals Handbook |publisher=ASM International |isbn=978-0-87170-654-6 |page=[https://archive.org/details/metalshandbook00davi/page/584 584] |url=https://archive.org/details/metalshandbook00davi |url-access=registration |via=Internet Archive (archive.org)}}

Titanium alloys are used in spectacle frames that are rather expensive but highly durable, long lasting, light weight, and cause no skin allergies. Titanium is a common material for backpacking cookware and eating utensils. Though more expensive than traditional steel or aluminium alternatives, titanium products can be significantly lighter without compromising strength. Titanium horseshoes are preferred to steel by farriers because they are lighter and more durable.{{harvnb|Donachie|1988|pp=11, 255}}

File:El Guggenheim vizcaíno. (1454058701).jpg's Guggenheim Museum, Bilbao]]

Titanium has occasionally been used in architecture. The {{convert|42.5|m|ft|adj=on|abbr=on}} Monument to Yuri Gagarin, the first man to travel in space ({{coord|55|42|29.7|N|37|34|57.2|E|region:CN-62_type:landmark|display=inline}}), as well as the {{convert|110|m|ft|adj=on|abbr=on}} Monument to the Conquerors of Space on top of the Cosmonaut Museum in Moscow are made of titanium for the metal's attractive color and association with rocketry.{{cite book|author=Mike Gruntman|title=Blazing the Trail: The Early History of Spacecraft and Rocketry|page=457|isbn=978-1-56347-705-8|url=https://books.google.com/books?id=2XY9KXxF8OEC|publisher=American Institute of Aeronautics and Astronautics|location=Reston, VA|year=2004|author-link=Mike Gruntman}}{{cite book|chapter-url=https://books.google.com/books?id=41EqJFxjA4wC&pg=PA408|title=Titanium |chapter= Appearance Related Applications|isbn=978-3-540-71397-5|author1=Lütjering, Gerd|author2=Williams, James Case|date=12 June 2007|publisher=Springer }} 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.{{harvnb|Emsley|2001|p=454}} Titanium sheathing was used in the Frederic C. Hamilton Building in Denver, Colorado.{{cite web |url=http://www.designbuild-network.com/projects/dam/ |title=Denver Art Museum, Frederic C. Hamilton Building |access-date=26 December 2006 |publisher=SPG Media |year=2006}}

Because of titanium's superior strength and light weight relative to other metals (steel, stainless steel, and aluminium), and because of recent advances in metalworking techniques, its use has become more 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, in Apple's PowerBook G4).{{cite web|access-date=8 August 2009|url=http://www.everymac.com/systems/apple/powerbook_g4/stats/powerbook_g4_400.html|title=Apple PowerBook G4 400 (Original – Ti) Specs|work=everymac.com}}

In 2023, Apple launched the iPhone 15 Pro, which uses a titanium enclosure.{{Cite web |title=Apple Announces iPhone 15 Pro Models With Titanium Enclosure |url=https://www.cnet.com/tech/mobile/apple-announces-iphone-15-pro-models-with-titanium-enclosure/ |access-date=2023-09-19 |website=CNET |language=en}}

Some upmarket lightweight and corrosion-resistant tools, such as shovels, knife handles and flashlights, are made of titanium or titanium alloys.{{cite book |pages=7–8 |year=2019 |isbn=978-0-12-815820-3 |publisher=Elsevier Science |title=Real-World Use of Titanium |author1=Qian, Ma |author2=Niinomi, Mitsuo}}

File:Anodized titanium table.jpg

Because of its durability, titanium has become more popular for designer jewelry (particularly, titanium rings). 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-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.{{cite journal |url=http://goldbulletin.org/assets/file/goldbulletin/downloads/Gafner_4_22.pdf |title=The development of 990 Gold-Titanium: its Production, use and Properties |author=Gafner, G. |journal=Gold Bulletin |year=1989 |volume=22 |issue=4 |pages=112–122 |doi=10.1007/BF03214709 |doi-access=free |s2cid=114336550 |archive-url=https://web.archive.org/web/20101129195740/http://goldbulletin.org/assets/file/goldbulletin/downloads/Gafner_4_22.pdf |archive-date=29 November 2010 }}

Titanium's durability, light weight, and dent and corrosion resistance make it useful for watch cases. Some artists work with titanium to produce sculptures, decorative objects and furniture.{{cite web|access-date=8 August 2009 |url=http://www.titanium-arts.com/home.html |title=Fine Art and Functional Works in Titanium and Other Earth Elements |archive-url=https://web.archive.org/web/20080513171451/http://www.titanium-arts.com/home.html |archive-date=13 May 2008 }}

Titanium may be anodized to vary the thickness of the surface oxide layer, causing optical interference fringes and a variety of bright colors.{{cite web|url=http://electrochem.cwru.edu/ed/encycl/art-a02-anodizing.htm |title=Electrochemistry Encyclopedia |publisher=Chemical Engineering Department, Case Western Reserve University, U.S.|author=Alwitt, Robert S. |year=2002 |access-date=30 December 2006 |archive-url=https://web.archive.org/web/20080702001336/http://electrochem.cwru.edu/ed/encycl/art-a02-anodizing.htm |archive-date=2 July 2008}} With this coloration and chemical inertness, titanium is a popular metal for body piercing.{{cite web |url=http://www.doctorgoodskin.com/tp/bodypiercing/|work=doctorgoodskin.com |title=Body Piercing Safety |date=1 August 2006}}

Titanium has a minor use in dedicated non-circulating coins and medals. In 1999, Gibraltar released the world's first titanium coin for the millennium celebration.{{Cite web|url=https://www.pobjoy.com/us/world-firsts|title=World Firsts|publisher=British Pobjoy Mint|access-date=11 November 2017|archive-date=26 February 2015|archive-url=https://web.archive.org/web/20150226055719/https://www.pobjoy.com/us/world-firsts|url-status=dead}} The Gold Coast Titans, an Australian rugby league team, award a medal of pure titanium to their player of the year.{{cite news|last=Turgeon |first=Luke |title=Titanium Titan: Broughton immortalised |url=http://www.goldcoast.com.au/article/2007/09/20/2947_gold-coast-titans.html |newspaper=The Gold Coast Bulletin |date=20 September 2007 |archive-url=https://web.archive.org/web/20130928082012/http://www.goldcoast.com.au/article/2007/09/20/2947_gold-coast-titans.html |archive-date=28 September 2013}}

{{Main|Titanium biocompatibility}}

Because titanium is biocompatible (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) and dental implants that can stay in place for up to 20 years.{{harvnb|Emsley|2001|p=452}} The titanium is often alloyed with about 4% aluminium or 6% Al and 4% vanadium.{{cite web|url=http://www.totaljoints.info/orthopaedic_metal_alloys.htm|title=Orthopaedic Metal Alloys|publisher=Totaljoints.info|access-date=27 September 2010}}

File:Titanium plaatje voor pols.jpg

Titanium has the inherent ability to osseointegrate, enabling use in dental implants that can last for over 30 years. This property is also useful for orthopedic implant applications. 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.{{cite journal |url=http://www.fraunhofer.de/en/press/research-news/2010/09/titanium-foams-replace-injured-bones.jsp|title=Titanium foams replace injured bones|journal=Research News |date=1 September 2010|archive-url=https://web.archive.org/web/20100904045008/http://www.fraunhofer.de/en/press/research-news/2010/09/titanium-foams-replace-injured-bones.jsp|access-date=27 September 2010|archive-date=4 September 2010}}{{cite journal | last=Lavine | first=Marc S. | editor-last=Vignieri | editor-first=Sacha | editor-last2=Smith | editor-first2=Jesse | title=Make no bones about titanium | journal=Science | volume=359 | issue=6372 | date=11 January 2018 | doi=10.1126/science.359.6372.173-f | pages=173.6–174| bibcode=2018Sci...359..173L | doi-access=free }}

Because 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.

Modern advancements in additive manufacturing techniques have increased potential for titanium use in orthopedic implant applications.{{cite journal | last1=Harun | first1=W.S.W. | last2=Manam | first2=N.S. | last3=Kamariah | first3=M.S.I.N. | last4=Sharif | first4=S. | last5=Zulkifly | first5=A.H. | last6=Ahmad | first6=I. | last7=Miura | first7=H. | title=A review of powdered additive manufacturing techniques for Ti-6al-4v biomedical applications | journal=Powder Technology | volume=331 | year=2018 | doi=10.1016/j.powtec.2018.03.010 | pages=74–97| url=http://irep.iium.edu.my/64319/1/A%20review%20of%20powdered%20additive%20manufacturing%20techniques%20for%20Ti-6al-4v%20biomedical%20applications.pdf }} Complex implant scaffold designs can be 3D-printed using titanium alloys, which allows for more patient-specific applications and increased implant osseointegration.{{cite journal | last1=Trevisan | first1=Francesco | last2=Calignano | first2=Flaviana | last3=Aversa | first3=Alberta | last4=Marchese | first4=Giulio | last5=Lombardi | first5=Mariangela | last6=Biamino | first6=Sara | last7=Ugues | first7=Daniele | last8=Manfredi | first8=Diego | year=2017 | title=Additive manufacturing of titanium alloys in the biomedical field: processes, properties and applications | journal=Journal of Applied Biomaterials & Functional Materials | volume=16 | issue=2 |pmid=28967051 | doi=10.5301/jabfm.5000371 | pages=57–67| s2cid=27827821 | doi-access=free }}

Titanium is 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.{{Cite book |year=2019 |isbn=978-0-12-815820-3 |publisher=Elsevier Science |title=Real-World Use of Titanium |author1=Qian, Ma |author2=Niinomi, Mitsuo |pages=51, 128 }}

Titanium dioxide nanoparticles are widely used in electronics and the delivery of pharmaceuticals and cosmetics.{{cite journal |last1=Pinsino |first1=Annalisa |last2=Russo |first2=Roberta |last3=Bonaventura |first3=Rosa |last4=Brunelli |first4=Andrea |last5=Marcomini |first5=Antonio |last6=Matranga |first6=Valeria |date=28 September 2015 |title=Titanium dioxide nanoparticles stimulate sea urchin immune cell phagocytic activity involving TLR/p38 MAPK-mediated signalling pathway |journal=Scientific Reports |volume=5 |doi=10.1038/srep14492 |pmc=4585977 |pmid=26412401 |page=14492 |bibcode=2015NatSR...514492P}}

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.{{cite journal |doi= 10.1515/CORRREV.2000.18.4-5.331 |title= Hydrogen Absorption and the Lifetime Performance of Titanium Nuclear Waste Containers |journal= Corrosion Reviews |volume= 18 |issue= 4–5 |year= 2000 |last1= Shoesmith |first1= D. W. |last2= Noel |first2= J. J. |last3= Hardie |first3= D. |last4= Ikeda |first4= B. M.|pages= 331–360 |s2cid= 137825823 }} A titanium "drip shield" could also be installed over containers of other types to enhance their longevity.{{cite journal |title=Proof of Safety at Yucca Mountain |journal=Science |year=2005|volume= 310 |issue=5747 |pages=447–448 |author1=Carter, L.J. |author2=Pigford, T.J. |doi=10.1126/science.1112786 |pmid=16239463 |s2cid=128447596}}

Titanium is non-toxic even in large doses and does not play any natural role inside the human body. An estimated quantity of 0.8 milligrams of titanium is ingested by humans each day, but most passes through without being absorbed in the tissues. It does, however, sometimes bio-accumulate in tissues that contain silica. One study indicates a possible connection between titanium and yellow nail syndrome.{{cite journal |last1=Berglund |first1=Fredrik |author2=Carlmark, Bjorn |title=Titanium, Sinusitis, and the Yellow Nail Syndrome |journal=Biological Trace Element Research |date=October 2011 |pmc=3176400 |volume=143 |issue=1 |pages=1–7 |doi=10.1007/s12011-010-8828-5 |pmid=20809268|bibcode=2011BTER..143....1B }}

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.{{cite book |last=Cotell |first=Catherine Mary |author2=Sprague, J.A. |author3=Smidt, F.A. |title=ASM Handbook: Surface Engineering |publisher=ASM International |year=1994 |edition=10th |page=836 |isbn=978-0-87170-384-2 |url=https://books.google.com/books?id=RGtsPjqUwy0C}} Water and carbon dioxide are ineffective for extinguishing a titanium fire; Class D dry powder agents must be used instead.

When used in the production or handling of chlorine, titanium should not be exposed to dry chlorine gas because it may result in a titanium–chlorine fire.{{cite book |author=Compressed Gas Association |title=Handbook of compressed gases |publisher=Springer |year=1999 |edition=4th |page=323 |isbn=978-0-412-78230-5 |url=https://books.google.com/books?id=WSLULtCG9JgC}}

Titanium can catch fire when a fresh, non-oxidized surface comes in contact with liquid oxygen.{{cite book |last=Solomon |first=Robert E. |others=National Fire Prevention Association |title=Fire and Life Safety Inspection Manual |publisher=Jones & Bartlett Publishers |year=2002 |edition=8th |page=45 |isbn=978-0-87765-472-8 |url=https://books.google.com/books?id=2fHsoobsCNwC}}

File:Kopiva.JPG contain up to 80 parts per million of titanium.]]

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.

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• Titanium alloys
• Suboxide
• Titanium in zircon geothermometry
• Titanium Man

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• {{cite book |title=The Encyclopedia of the Chemical Elements|publisher=Reinhold Book Corporation |location=New York, NY |year=1968 |editor=Clifford A. Hampel |last=Barksdale |first=Jelks |chapter=Titanium |pages=[https://archive.org/details/encyclopediaofch00hamp/page/732 732–738] |lccn=68029938 |chapter-url=https://archive.org/details/encyclopediaofch00hamp |chapter-url-access=registration}}
• {{cite book |title=Titanium: A technical guide |year=1988 |last1=Donachie| first1=Matthew J. Jr. |publisher=ASM International |location=Metals Park, OH |page=11 |isbn=978-0-87170-309-5 |url=https://books.google.com/books?id=Ct9RAAAAMAAJ}}
• {{cite book |title=Nature's Building Blocks: An A-Z guide to the elements |last=Emsley |first=John |publisher=Oxford University Press |year=2001 |location=Oxford, England, UK |isbn=978-0-19-850340-8 |chapter=Titanium |chapter-url=https://books.google.com/books?id=j-Xu07p3cKwC|url-access=registration|url=https://archive.org/details/naturesbuildingb0000emsl}}
• {{cite journal |last=Flower |first=Harvey M.|title=Materials Science: A moving oxygen story |journal=Nature |volume=407 |year=2000 |issue=6802 |pmid=11014169 |pages=305–306 |doi=10.1038/35030266 |s2cid=4425634 }}
• {{cite book|last1=Greenwood|first1=N. N.|last2=Earnshaw|first2=A. |title=Chemistry of the Elements|edition=2nd|publisher=Butterworth-Heinemann|location=Oxford|year=1997|isbn=978-0-7506-3365-9}}
• {{cite book |last1=Roza |first1=Greg |title=Titanium |year=2008 |publisher=The Rosen Publishing Group |location=New York, NY |isbn=978-1-4042-1412-5 |edition=1st |url=https://books.google.com/books?id=rsAGRf7j7fQC}}

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{{Sister project links|titanium|b=no |n=no |q=no |s=no |v= |species=no}}

• [https://books.google.com/books?id=7iwDAAAAMBAJ&pg=RA2-PA46 "Titanium: Our Next Major Metal"] in Popular Science (October 1950), one of first general public detailed articles on Titanium
• [http://www.periodicvideos.com/videos/022.htm Titanium] at Periodic Videos (University of Nottingham)
• [https://titanium.org/ Titanium.org]: official website of the International Titanium Association, an industry association
• [https://www.phase-trans.msm.cam.ac.uk/2003/titanium.movies/titanium.html Metallurgy of Titanium and its Alloys] - slide presentations, movies, and other material from Harshad Bhadeshia and other Cambridge University metallurgists

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