AskDefine | Define titanium

Dictionary Definition

titanium n : a light strong gray lustrous corrosion-resistant metallic element used in strong light-weight alloys (as for airplane parts); the main sources are rutile and ilmenite [syn: Ti, atomic number 22]

User Contributed Dictionary

English

Etymology

From Τιτάν, Titan

Pronunciation

Noun

(Symbol: Ti)
  1. a chemical element, atomic number 22; it is a strong, corrosion-resistant transition metal, used to make light alloys for aircraft etc .

Translations

External links

For more information refer to: http://elements.vanderkrogt.net/elem/ti.html (A lot of the translations were taken from that site with permission from the author)

Extensive Definition

Titanium () is a chemical element with the symbol Ti and atomic number 22. It is a light, strong, lustrous, corrosion-resistant (including to sea water and chlorine) transition metal with a grayish color. Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial process (chemicals and petro-chemicals, desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopaedic implants, dental endodontic instruments and files), dental implants), sporting goods, jewelry, and other applications. Titanium was discovered in England by William Gregor in 1791 and named by Martin Heinrich Klaproth for the Titans of Greek mythology.
The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, rocks, water bodies, and soils. Other compounds include titanium tetrachloride (TiCl4) (used in smoke screens/skywriting and as a catalyst) and titanium trichloride (used as a catalyst in the production of polypropylene). In its unalloyed condition, titanium is as strong as some steels, but 45% lighter. and five naturally occurring isotopes of this element; 46Ti through 50Ti with 48Ti being the most abundant (73.8%). Titanium's properties are chemically and physically similar to zirconium.

History

Titanium was discovered combined in a mineral in Cornwall, England in 1791 by amateur geologist and pastor William Gregor, the then vicar of Creed parish. He recognized the presence of a new element in ilmenite Gregor, realizing that the unidentified oxide contained a metal that did not match the properties of any known element, reported his findings to the Royal Geological Society of Cornwall and in the German science journal Crell's Annalen.
Around the same time, Franz Joseph Muller also produced a similar substance, but could not identify it. Klaproth found that it contained a new element and named it for the Titans of Greek mythology.
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 the early 1950s, Titanium began to be used extensively for military aviation purposes, particularly in high-performance jets, starting with aircraft such as the F100 Super Sabre and Lockheed A-12.
In the USA, the Department of Defense realized the strategic importance of the metal and supported early efforts of commercialization. Throughout the period of the Cold War, titanium was considered a Strategic Material by the U.S. government, and a large stockpile of titanium sponge was maintained by the Defense National Stockpile Center, which was finally depleted in 2005. Today, the world's largest producer, Russian-based VSMPO-Avisma, is estimated to account for about 29% of the world market share.
In 2006, the U.S. Defense Agency awarded $5.7 million to a two-company consortium to develop a new process for making titanium metal powder. Under heat and pressure, the powder can be used to create strong, lightweight items ranging from armor plating to components for the aerospace, transportation, and chemical processing industries.

Characteristics

Physical

A metallic element, titanium is recognized for its high strength-to-weight ratio. lustrous, and metallic-white in color. The relatively high melting point (over 1,649 °C or 3,000 °F) makes it useful as a refractory metal.
Commercial (99.2% pure) grades of titanium have ultimate tensile strength of about 63,000 psi (434 MPa), equal to that of some steel alloys, but are 45% lighter. However, titanium loses strength when heated above 430 °C (800 °F).
The metal is a dimorphic allotrope with the hexagonal alpha form changing into the body-centered cubic (lattice) beta form at 882 °C (1,619 °F).

Chemical

The most noted chemical property of titanium is its excellent resistance to corrosion; it is almost as resistant as platinum, capable of withstanding attack by acids, moist chlorine gas, and by common salt solutions.
While the following pourbaix diagram shows that titanium is thermodynamically a very reactive metal, it is slow to react with water and air.
This metal forms a passive and protective oxide coating (leading to increased corrosion-resistance) when exposed to elevated temperatures in air, but at room temperatures it resists tarnishing. Titanium is resistant to dilute sulfuric and hydrochloric acid, along with chlorine gas, chloride solutions, and most organic acids.Due to rounding, values do not sum to 100%.
Titanium is always bonded to other elements in nature. It is the ninth-most abundant element in the Earth's crust (0.63% by mass) In fact, of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium. 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 the metal reacts with oxygen at high temperatures it cannot be produced by reduction of its dioxide. Titanium metal is therefore produced commercially by the Kroll process, a complex and expensive batch process. (The relatively high market value of titanium is mainly due to its processing, which sacrifices another expensive metal, magnesium. may eventually replace the Kroll process. This method uses titanium dioxide powder (which is a refined form of rutile) as feedstock to make the end product which is either a powder or sponge. If mixed oxide powders are used, the product is an alloy manufactured at a much lower cost than the conventional multi-step melting process. The FFC Cambridge process may render titanium a less rare and expensive material for the aerospace industry and the luxury goods market, and could be seen in many products currently manufactured using aluminium and specialist grades of steel.
Common titanium alloys are made by reduction. For example, cuprotitanium (rutile with copper added is reduced), ferrocarbon titanium (ilmenite reduced with coke in an electric furnace), and manganotitanium (rutile with manganese or manganese oxides) are reduced. The ASTM International recognizes 31 Grades of titanium metal and alloys, of which Grades 1 through 4 are commercially pure (unalloyed). These four are distinguished by their varying degrees of tensile strength, as a function of oxygen content, with Grade 1 being the most ductile (lowest tensile strength with an oxygen content of 0.18%), and Grade 4 the least (highest tensile strength with an oxygen content of 0.40%).
The grades covered by ASTM and other alloys are also produced to meet Aerospace and Military specifications (SAE-AMS, MIL-T), ISO standards, and country-specific specifications, as well as proprietary end-user specifications for aerospace, military, medical, and industrial applications.
In terms of fabrication, all welding of titanium must be done in an inert atmosphere of argon or helium in order to shield it from contamination with atmospheric gases such as oxygen, nitrogen, or hydrogen. The metal can be machined using the same equipment and via the same processes as stainless steel. Applications for titanium mill products (sheet, plate, bar, wire, forgings, castings) can be found in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright-burning particles.
Titanium is used in watchmaking for the production of watch cases. Watchmakers appreciate titanium for its durability, light weight, dent- and corrosion- resistance. Titanium watches are often coated with a protective material to make the surface more scratch-resistant.

Pigments, Additives and Coatings

About 95% of titanium ore extracted from the Earth is destined for refinement into titanium dioxide (), an intensely white permanent pigment used in paints, paper, toothpaste, and plastics. It is also used in cement, in gemstones, as an optical opacifier in paper, and a strengthening agent in graphite composite fishing rods and golf clubs.
powder is chemically inert, resists fading in sunlight, and is very opaque: this allows it to impart a pure and brilliant white color to the brown or gray chemicals that form the majority of household plastics.

Aerospace and marine

Due to their high tensile strength to density ratio, In engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles. The titanium 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications.
Due to its high corrosion resistance to sea water, titanium is used to make propeller shafts and rigging and in the heat exchangers of desalination plants;
Titanium commercial aerospace requirements (including engine components [e.g., blades, discs, rings and engine cases] and airframe components [e.g., bulkheads, tail sections, landing gear, wing supports and fasteners]) for the manufacture of:
Boeing (including both the airframes and engines)
  • B787 – 295,000 pounds (133.8 tonne) of titanium
  • B777 – 130,000 pounds (59 tonne) of titanium
  • B747 – 100,000 pounds (45.4 tonne) of titanium
  • B737 – 40,000 pounds (18.1 tonne) of titanium
Airbus (including both the airframes and engines)
  • A380 – 320,000 pounds (145.1 tonne) of titanium
  • A350 – 165,000 pounds (74.8 tonne) of titanium (estimated minimal requirement)
  • A340 – 70,000 pounds (31.8 tonne) of titanium
  • A330 – 40,000 pounds (18.1 tonne) of titanium
  • A320 – 26,000 pounds (11.8 tonne) of titanium
Source: TIMET 2007 Form 10-K (converted from metric tons to pounds)

Industrial

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

Consumer and architectural

Titanium metal is used in automotive applications, particularly in automobile or motorcycle racing, where weight reduction is critical while maintaining high strength and rigidity. The metal is generally too expensive to make it marketable to the general consumer market, other than high-end products. Late model Corvettes have been available with titanium exhausts, and racing bikes are frequently outfitted with titanium mufflers. Titanium alloy is used for the connecting rods in the engine of the 2006 and later Corvette Z06. Other automotive uses include piston rods and hardware (bolts, nuts, etc.).
The Parker Pen Company used titanium to form the T-1 fountain pen, later expanded to T-1 ball pens and rollerballs. The T-1 fountain pen was introduced in 1970 and the T-1 rollerball and ball pen in 1971. Production was stopped in 1972 due to the high cost of manufacturing titanium. Parker T-1's are prized for their collectibility by collectors.
Hammer heads made of titanium were introduced in 1999. Their light weight allows for a longer handle which increases the velocity of the head and results in more energy being delivered to the nail, all while decreasing arm fatigue. Titanium also decreases the shock transferred to the user because a titanium head generates about 3% recoil compared to a steel head that generates about 27%.
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. Titanium alloys are also used in spectacle frames. This results in a rather expensive, but highly durable and long lasting frame which is light in weight and causes no skin allergies. Many backpackers use titanium equipment, including cookware, eating utensils, lanterns, and tent stakes. Though slightly more expensive than traditional steel or aluminium alternatives, these titanium products can be significantly lighter without compromising strength. Titanium is also favored for use by farriers, since it is lighter and more durable than steel when formed into horseshoes. Titanium horseshoes can be found in horse racing, and are used by many Amish horse owners, who rely entirely on horse-drawn carriages for transportation. Titanium has even become somewhat popular for use in jewelry, such as rings and body piercings.
Because of its durability, titanium has become more popular for designer jewelry in recent years, whereas until recently the metal was too difficult to work into the intricate shapes with the precision necessary for fine jewelry. Today, titanium rings — including engagement rings and wedding bands — are one of the fastest growing segments of the titanium jewelry market, in part due to the ability of the metal to be grooved, inlaid, and carved without losing strength. Some titanium jewelry also incorporates diamonds or other gemstones, typically in close settings such as bezels, flush, or tension designs. Its inertness again makes it a good choice for those with allergies or those who will be wearing the jewelry in environments such as swimming pools.
Titanium has occasionally been used in architectural applications: the 120 foot (40 m) memorial to Yuri Gagarin, the first man to travel in space, in Moscow, is made of titanium for the metal's attractive color and association with rocketry. 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. Other construction uses of titanium sheathing include the Frederic C. Hamilton Building in (Denver, Colorado) and the 350 foot (107 m) Monument to the Conquerors of Space in Moscow.
Due to its superior strength and light weight when compared to other metals traditionally used in firearms (steel, stainless steel, and aluminium), and advances in metal-working techniques, the use of titanium has become more widespread in the manufacture of firearms. Primary uses include pistol frames and revolver cylinders.

Medical

Because it is biocompatible (non-toxic and is not rejected by the body), titanium is used in a gamut of medical applications including surgical implements and implants, such as hip balls and sockets (joint replacement) that can stay in place for up to 20 years. Titanium has the inherent property to osseointegrate, enabling use in dental implants that can remain in place for over 30 years. This property is also useful for orthopedic implant applications. Titanium may be anodized to produce various colors. A number of artists work with titanium to produce artworks such as sculptures, decorative objects, and furniture.

Compounds

The +4 oxidation state dominates in titanium chemistry, but compounds in the +3 oxidation state are also common. Because of this high oxidation state, many titanium compounds have a high degree of covalent bonding.
Star sapphires and rubies get their asterism from the titanium dioxide impurities present in them. Titanates are compounds made with titanium dioxide. Barium titanate has piezoelectric properties, thus making it possible to use it as a transducer in the interconversion of sound and electricity. Esters of titanium are formed by the reaction of alcohols and titanium tetrachloride and are used to waterproof fabrics.
Titanium nitride (TiN) is often used to coat cutting tools, such as drill bits. It also finds use as a gold-coloured decorative finish, and as a barrier metal in semiconductor fabrication.
Titanium tetrachloride (titanium(IV) chloride, TiCl4, sometimes called "Tickle") is a colourless liquid which is used as an intermediate in the manufacture of titanium dioxide for paint. It is widely used in organic chemistry as a Lewis acid, for example in the Mukaiyama aldol condensation. Titanium also forms a lower chloride, titanium(III) chloride (TiCl3), which is used as a reducing agent.
Titanocene dichloride is an important catalyst for carbon-carbon bond formation. Titanium isopropoxide is used for Sharpless epoxidation. Other compounds include titanium bromide (used in metallurgy, superalloys, and high-temperature electrical wiring and coatings) and titanium carbide (found in high-temperature cutting tools and coatings).

Isotopes

Naturally occurring titanium is composed of 5 stable isotopes: 46Ti, 47Ti, 48Ti, 49Ti, and 50Ti, with 48Ti being the most abundant (73.8% natural abundance). Eleven radioisotopes have been characterized, with the most stable being 44Ti with a half-life of 63 years, 45Ti with a half-life of 184.8 minutes, 51Ti with a half-life of 5.76 minutes, and 52Ti with a half-life of 1.7 minutes. All of the remaining radioactive isotopes have half-lives that are less than 33 seconds and the majority of these have half-lives that are less than half a second.
The isotopes of titanium range in atomic weight from 39.99 u (40Ti) to 57.966 u (58Ti). The primary decay mode before the most abundant stable isotope, 48Ti, is electron capture and the primary mode after is beta emission. The primary decay products before 48Ti are element 21 (scandium) isotopes and the primary products after are element 23 (vanadium) isotopes.

Precautions

Titanium is non-toxic even in large doses and does not play any natural role inside the human body. An estimated 0.8 milligrams of titanium is ingested by humans each day but most passes through without being absorbed. It does, however, have a tendency to bio-accumulate in tissues that contain silica. 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.
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. Water and carbon dioxide-based methods to extinguish fires are ineffective on burning titanium; Class D dry powder fire fighting agents must be used instead.
Even bulk titanium metal is susceptible to fire, when it is heated to its melting point. A number of titanium fires occur during breaking down devices containing titanium parts with cutting torches.
When used in the production or handling of chlorine, care must be taken to use titanium only in locations where it will not be exposed to dry chlorine gas which can result in a titanium/chlorine fire. Care must be taken even when titanium is used in wet chlorine due to possible unexpected drying brought about by extreme weather conditions.
Titanium can catch fire when a fresh, non-oxidized surface gets in contact with liquid oxygen. Such surfaces can appear when the oxidized surface is struck with a hard object, or when a mechanical strain causes the emergence of a crack. This poses the possible limitation for its use in liquid oxygen systems, such as those found in the aerospace industry.
Salts of titanium are often considered to be relatively harmless, but its chlorine compounds, such as TiCl2, TiCl3, and TiCl4, have presented several unusual hazards. The dichloride takes the form of pyrophoric black crystals, and the tetrachloride is a volatile fuming liquid. All of titanium's chlorides are corrosive.

References

  • Guide to the Elements (Revised Edition)
  • Book of Titanium, Ehsan Ghandhari (2007)

External links

titanium in Afrikaans: Titaan
titanium in Arabic: تيتانيوم
titanium in Azerbaijani: Titan
titanium in Bengali: টাইটানিয়াম
titanium in Belarusian: Тытан
titanium in Bosnian: Titanijum
titanium in Bulgarian: Титан (елемент)
titanium in Catalan: Titani
titanium in Czech: Titan (prvek)
titanium in Corsican: Titaniu
titanium in Danish: Titan (grundstof)
titanium in German: Titan (Element)
titanium in Estonian: Titaan
titanium in Modern Greek (1453-): Τιτάνιο
titanium in Spanish: Titanio
titanium in Esperanto: Titano (elemento)
titanium in Basque: Titanio
titanium in Persian: تیتانیوم
titanium in French: Titane
titanium in Friulian: Titani
titanium in Manx: Çhitaanium
titanium in Galician: Titanio
titanium in Korean: 타이타늄
titanium in Armenian: Տիտան
titanium in Hindi: टाइटानियम
titanium in Croatian: Titanij
titanium in Ido: Titanio
titanium in Indonesian: Titanium
titanium in Icelandic: Títan
titanium in Italian: Titanio
titanium in Hebrew: טיטניום
titanium in Javanese: Titanium
titanium in Kannada: ಟೈಟೇನಿಯಮ್
titanium in Swahili (macrolanguage): Titani
titanium in Haitian: Titàn
titanium in Kurdish: Tîtanyûm
titanium in Latin: Titanium
titanium in Latvian: Titāns
titanium in Luxembourgish: Titan (Element)
titanium in Lithuanian: Titanas
titanium in Lojban: jinmrtitani
titanium in Hungarian: Titán (elem)
titanium in Malayalam: ടൈറ്റാനിയം
titanium in Marathi: टायटॅनियम
titanium in Dutch: Titanium
titanium in Japanese: チタン
titanium in Norwegian: Titan (grunnstoff)
titanium in Norwegian Nynorsk: Grunnstoffet titan
titanium in Occitan (post 1500): Titani
titanium in Uzbek: Titan (unsur)
titanium in Low German: Titan (Element)
titanium in Polish: Tytan (pierwiastek)
titanium in Portuguese: Titânio
titanium in Romanian: Titan
titanium in Quechua: Titanyu
titanium in Russian: Титан (элемент)
titanium in Sicilian: Titaniu
titanium in Simple English: Titanium
titanium in Slovak: Titán
titanium in Slovenian: Titan (element)
titanium in Serbian: Титанијум
titanium in Serbo-Croatian: Titanij
titanium in Finnish: Titaani
titanium in Swedish: Titan (grundämne)
titanium in Tamil: டைட்டேனியம்
titanium in Thai: ไทเทเนียม
titanium in Vietnamese: Titan
titanium in Turkish: Titanyum
titanium in Ukrainian: Титан (хімічний елемент)
titanium in Yiddish: טיטאניום
titanium in Chinese: 钛
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