Misplaced Pages

#24975

57-483: Titanium(II) oxide ( Ti O ) is an inorganic chemical compound of titanium and oxygen. It can be prepared from titanium dioxide and titanium metal at 1500 °C. It is non-stoichiometric in a range TiO 0.7 to TiO 1.3 and this is caused by vacancies of either Ti or O in the defect rock salt structure. In pure TiO 15% of both Ti and O sites are vacant, as the vacancies allow metal-metal bonding between adjacent Ti centres. Careful annealing can cause ordering of

114-631: 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. 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. Because it cannot be readily produced by reduction of titanium dioxide, titanium metal

171-464: A carbon monoxide atmosphere with chlorine gas before reducing it to titanium metal by the use of sodium. Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl 4 with sodium at 700–800 °C (1,292–1,472 °F) under great pressure in a batch process known as the Hunter process . Titanium metal was not used outside

228-687: A couple of dozen are readily available commercially. 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. In addition to

285-411: A fundamental limit on the specific strength of any material. The specific strength is bounded to be no greater than c ≈ 9 × 10   kN ⋅ m / kg , where c is the speed of light . This limit is achieved by electric and magnetic field lines, QCD flux tubes , and the fundamental strings hypothesized by string theory . Tenacity is the customary measure of strength of a fiber or yarn . It

342-438: A mixture of oxides and deposits coatings with variable refractive index. Also known is Ti 2 O 3 , with the corundum structure, and TiO , with the rock salt structure , although often nonstoichiometric . The alkoxides of titanium(IV), prepared by treating TiCl 4 with alcohols , are colorless compounds that convert to the dioxide on reaction with water. They are industrially useful for depositing solid TiO 2 via

399-434: A reducing agent in organic 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 ((C 5 H 5 ) 2 TiCl 2 ). Related compounds include Tebbe's reagent and Petasis reagent . Titanium forms carbonyl complexes , e.g. (C 5 H 5 ) 2 Ti(CO) 2 . Following

456-472: A sample of manaccanite and confirmed that it contained titanium. 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

513-725: A variety of conditions, such as embrittlement , which reduce the integrity of the assembly welds and lead to joint failure. Titanium is very difficult to solder directly, and hence a solderable metal or alloy such as steel is coated on titanium prior to soldering. Titanium metal can be machined with the same equipment and the same processes as stainless steel . 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. About fifty grades of titanium alloys are designed and currently used, although only

570-421: Is positron emission (with the exception of Ti which undergoes electron capture ), leading to isotopes of scandium , and the primary mode for isotopes heavier than Ti is beta emission , leading to isotopes of vanadium . Titanium becomes radioactive upon bombardment with deuterons , emitting mainly positrons and hard gamma rays . The +4 oxidation state dominates titanium chemistry, but compounds in

627-472: Is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy . Certain titanium alloys (e.g., Beta C ) achieve tensile strengths of over 1,400 MPa (200,000 psi). However, titanium loses strength when heated above 430 °C (806 °F). 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

SECTION 10

#1732780079025

684-473: Is about 4 picomolar in the ocean. At 100 °C, the concentration of titanium in water is estimated to be less than 10 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. Titanium

741-548: Is also considered one of the most biocompatible metals, leading to a range of medical applications including prostheses , orthopedic implants , dental implants , and surgical instruments . The two most useful properties of the metal are corrosion resistance and strength-to-density ratio , the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels , but less dense. There are two allotropic forms and five naturally occurring isotopes of this element, Ti through Ti, with Ti being

798-500: Is also very hard, is found in cutting tools and coatings. Titanium tetrachloride (titanium(IV) chloride, TiCl 4 ) is a colorless volatile liquid (commercial samples are yellowish) that, in air, hydrolyzes with spectacular emission of white clouds. Via the Kroll process , TiCl 4 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. It

855-854: 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

912-490: Is conceived to be the SI unit for yield stress (or breaking stress) per unit of density of a material under tension. One Yuri equals 1 Pa⋅m /kg or 1  N ⋅ m / kg , which is the breaking/yielding force per linear density of the cable under tension. A functional Earth space elevator would require a tether of 30–80 megaYuri (corresponding to 3100–8200 km of breaking length). The null energy condition places

969-637: 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 3,200 °C (5,790 °F). Rocks brought back from the Moon during the Apollo 17 mission are composed of 12.1% TiO 2 . Native titanium (pure metallic) is very rare. Naturally occurring titanium is composed of five stable isotopes : Ti, Ti, Ti, Ti, and Ti, with Ti being

1026-489: Is corroded by concentrated acids. 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 550 °C (1,022 °F), it combines with chlorine. It also reacts with the other halogens and absorbs hydrogen. Titanium readily reacts with oxygen at 1,200 °C (2,190 °F) in air, and at 610 °C (1,130 °F) in pure oxygen, forming titanium dioxide . Titanium

1083-897: Is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide , is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl 4 ), a component of smoke screens and catalysts ; and titanium trichloride (TiCl 3 ), which is used as a catalyst in the production of polypropylene . Titanium can be alloyed with iron , aluminium , vanadium , and molybdenum , among other elements. The resulting titanium alloys are strong, lightweight, and versatile, with applications including aerospace ( jet engines , missiles , and spacecraft ), military, industrial processes (chemicals and petrochemicals, desalination plants , pulp , and paper ), automotive, agriculture (farming), sporting goods, jewelry, and consumer electronics . Titanium

1140-406: Is heated to this transition temperature but then falls and remains fairly constant for the β form regardless of temperature. 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

1197-829: Is manufactured using a flow production process known as the Armstrong process 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. Methods for electrolytic production of Ti metal from TiO 2 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." A 2023 review "discusses

SECTION 20

#1732780079025

1254-426: Is not the case. It is paramagnetic and has fairly low electrical and thermal conductivity compared to other metals. Titanium is superconducting when cooled below its critical temperature of 0.49 K. Commercially pure (99.2% pure) grades of titanium have ultimate tensile strength of about 434  MPa (63,000  psi ), equal to that of common, low-grade steel alloys, but are less dense. Titanium

1311-565: Is obtained by reduction of titanium tetrachloride (TiCl 4 ) 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, despite the Kroll process being less expensive than the Hunter process. To produce the TiCl 4 required by the Kroll process, the dioxide is subjected to carbothermic reduction in

1368-511: Is one of the few elements that burns in pure nitrogen gas, reacting at 800 °C (1,470 °F) to form titanium nitride , which causes embrittlement. 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

1425-469: 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

1482-483: Is surrounded by six oxide ligands that link to other Ti centers. The term titanates usually refers to titanium(IV) compounds, as represented by barium titanate (BaTiO 3 ). 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 (FeTiO 3 ). Star sapphires and rubies get their asterism (star-forming shine) from

1539-547: Is the acceleration due to gravity ( ≈ 9.8 {\displaystyle \approx 9.8} m/s 2 {\displaystyle ^{2}} ) The data of this table is from best cases, and has been established for giving a rough figure. Note: Multiwalled carbon nanotubes have the highest tensile strength of any material yet measured, with labs producing them at a tensile strength of 63 GPa, still well below their theoretical limit of 300 GPa. The first nanotube ropes (20 mm long) whose tensile strength

1596-709: Is the force of gravity at the Earth's surface ( standard gravity , 9.80665 m/s ) applying to the entire length of the material, not diminishing with height. This usage is more common with certain specialty fiber or textile applications. The materials with the highest specific strengths are typically fibers such as carbon fiber , glass fiber and various polymers, and these are frequently used to make composite materials (e.g. carbon fiber-epoxy ). These materials and others such as titanium , aluminium , magnesium and high strength steel alloys are widely used in aerospace and other applications where weight savings are worth

1653-681: 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. 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). Akaogiite

1710-400: Is used in pyrotechnics as a source of bright-burning particles. Specific strength Another way to describe specific strength is breaking length , also known as self support length : the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. For this measurement, the definition of weight

1767-471: 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. Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets. Powdered titanium

Titanium(II) oxide - Misplaced Pages Continue

1824-514: Is widely used in organic chemistry as a Lewis acid , for example in the Mukaiyama aldol condensation . In the van Arkel–de Boer process , titanium tetraiodide (TiI 4 ) is generated in the production of high purity titanium metal. Titanium(III) and titanium(II) also form stable chlorides. A notable example is titanium(III) chloride (TiCl 3 ), which is used as a catalyst for production of polyolefins (see Ziegler–Natta catalyst ) and

1881-716: The Defense National Stockpile Center , until the stockpile was dispersed in the 2000s. As of 2021, the four leading producers of titanium sponge were China (52%), Japan (24%), Russia (16%) and Kazakhstan (7%). 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. The process involves reducing titanium tetrachloride (TiCl 4 ) with sodium (Na) in

1938-572: 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." 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

1995-484: The sol-gel process . Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation . Titanium forms a variety of sulfides, but only TiS 2 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

2052-540: The +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl 4 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 TiO 2 , 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

2109-464: 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. Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account of the tendency of

2166-471: The creation of potentially effective, selective, and stable titanium-based drugs. 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

2223-524: 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 . 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

2280-517: The first time; a result which is still debated in the literature. Additionally, evidence has been obtained for the presence of the diatomic molecule TiO in the interstellar medium. Titanium Titanium is a chemical element ; it has symbol Ti and atomic number 22. Found in nature only as an oxide , it can be reduced to produce a lustrous transition metal with a silver color , low density , and high strength, resistant to corrosion in sea water , aqua regia , and chlorine . Titanium

2337-424: The higher material cost. Note that strength and stiffness are distinct. Both are important in design of efficient and safe structures. where L {\displaystyle L} is the length, T s {\displaystyle T_{s}} is the tensile strength, ρ {\displaystyle \rho } is the density and g {\displaystyle \mathbf {g} }

Titanium(II) oxide - Misplaced Pages Continue

2394-558: 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." The Hydrogen assisted magnesiothermic reduction (HAMR) process uses titanium dihydride . 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

2451-522: The laboratory until 1932 when William Justin Kroll produced it by reducing titanium tetrachloride (TiCl 4 ) with calcium . 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. Titanium of very high purity

2508-431: The material can gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a fatigue limit that guarantees longevity in some applications. The metal is a dimorphic allotrope of a hexagonal close packed α form that changes into a body-centered cubic (lattice) β form at 882 °C (1,620 °F). The specific heat of the α form increases dramatically as it

2565-503: The metal to springback . This is especially true of certain high-strength alloys. 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. The working of titanium is very complicated, and may include Friction welding , cryo-forging , and Vacuum arc remelting . Titanium

2622-403: The most abundant (73.8%). As a metal , titanium is recognized for its high strength-to-weight ratio . It is a strong metal with low density that is quite ductile (especially in an oxygen -free environment), lustrous, and metallic-white in color . Due to its relatively high melting point (1,668 °C or 3,034 °F) it has sometimes been described as a refractory metal , but this

2679-507: The most abundant (73.8% natural abundance ). At least 21 radioisotopes have been characterized, the most stable of which are Ti with a half-life of 63 years; Ti, 184.8 minutes; Ti, 5.76 minutes; and Ti, 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 39.002  Da ( Ti) to 63.999 Da ( Ti). The primary decay mode for isotopes lighter than Ti

2736-530: The oxide with release of hydrogen sulfide . Titanium nitride (TiN) is a refractory solid exhibiting extreme hardness, thermal/electrical conductivity, and a high melting point. TiN has a hardness equivalent to sapphire and carborundum (9.0 on the Mohs scale ), and is often used to coat cutting tools, such as drill bits . It is also used as a gold-colored decorative finish and as a barrier layer in semiconductor fabrication . Titanium carbide (TiC), which

2793-475: 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 TiCl 4 is reduced with 800 °C (1,470 °F) molten magnesium in an argon atmosphere. The van Arkel–de Boer process was the first semi-industrial process for pure Titanium. It involves thermal decomposition of titanium tetraiodide . Titanium powder

2850-505: 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 . Ti 3 O 5 , described as a Ti(IV)-Ti(III) species, is a purple semiconductor produced by reduction of TiO 2 with hydrogen at high temperatures, and is used industrially when surfaces need to be vapor-coated with titanium dioxide: it evaporates as pure TiO, whereas TiO 2 evaporates as

2907-440: 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. 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 . He named this oxide manaccanite . Around

SECTION 50

#1732780079025

2964-760: 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). 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

3021-517: 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

3078-454: The vacancies producing a monoclinic form which has 5 TiO units in the primitive cell that exhibits lower resistivity. A high temperature form with titanium atoms with trigonal prismatic coordination is also known. Acid solutions of TiO are stable for a short time then decompose to give hydrogen: Gas-phase TiO shows strong bands in the optical spectra of cool ( M-type ) stars. In 2017, TiO was claimed to be detected in an exoplanet atmosphere for

3135-415: Was discovered in Cornwall , Great Britain , by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology . The element occurs within a number of minerals , principally rutile and ilmenite , which are widely distributed in the Earth's crust and lithosphere ; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal

3192-482: 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. In the 1950s and 1960s, the Soviet Union pioneered the use of titanium in military and submarine applications ( Alfa class and Mike class ) as part of programs related to the Cold War. Starting in

3249-439: Was published (in 2000) had a strength of 3.6 GPa, still well below their theoretical limit. The density is different depending on the manufacturing method, and the lowest value is 0.037 or 0.55 (solid). The International Space Elevator Consortium uses the "Yuri" as a name for the SI units describing specific strength. Specific strength is of fundamental importance in the description of space elevator cable materials. One Yuri

#24975