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5 décembre 2011 1 05 /12 /décembre /2011 03:14

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant (including sea water, aqua regia and chlorine) transition metal with a silver color.

Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and named by Martin Heinrich Klaproth for theTitans of Greek mythology. HP Pavilion DV4 Battery

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. The metal is extracted from its principal mineral ores via the Kroll process or the Hunter process. HP Pavilion DV4-1000 Battery

Its most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments.[4] Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride(TiCl3), which is used as a catalyst in the production of polypropylene.HP Pavilion DV4-1000EA Battery

Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial process (chemicals and petro-chemicals,desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.HP Pavilion DV4-1000ET Battery

The two most useful properties of the metal form are corrosion resistance and the highest strength-to-weight ratio of any metal.[5] In its unalloyed condition, titanium is as strong as some steels, but 45% lighter.[6] There are two allotropicforms[7] and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant(73.8%).HP Pavilion DV4-1001 Battery

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

Physical properties

A metallic element, titanium is recognized for its high strength-to-weight ratio.HP Pavilion DV4-1001AX Battery

It is a strong metal with low densitythat is quite ductile (especially in an oxygen-free environment),[2] lustrous, and metallic-white in color.[9] The relatively high melting point (more than 1,650 °C or 3,000 °F) makes it useful as a refractory metal. It is paramagnetic and has fairly low electrical and thermal conductivity.HP Pavilion DV4-1001TU Battery

Commercial (99.2% pure) grades of titanium have ultimate tensile strength of about 63,000 psi (434 MPa), equal to that of common, low-grade steel alloys, but are 45% lighter.[6] Titanium is 60% more dense than aluminium, but more than twice as strong[6] as the most commonly used 6061-T6 aluminium alloy. HP Pavilion DV4-1001TX Battery

Certain titanium alloys (e.g., Beta C) achieve tensile strengths of over 200,000 psi (1,400 MPa).[10] However, titanium loses strength when heated above 430 °C (806 °F).[11]

It is fairly hard (although not as hard as some grades of heat-treated steel), non-magnetic and a poor conductor of heat and electricity. HP Pavilion DV4-1002 Battery

Machining requires precautions, as the material will soften and gall if sharp tools and proper cooling methods are not used. Like those made from steel, titanium structures have a fatigue limit which guarantees longevity in some applications. Titanium alloys specific stiffnesses are also usually not as good as other materials such as aluminium alloys and carbon fiber, so it is used less for structures which require high rigidity.HP Pavilion DV4-1002AX Battery

The metal is a dimorphic allotrope whose hexagonal alpha form changes into a body-centered cubic (lattice) ? form at 882 °C(1,620 °F).[11] The specific heat of the alpha form increases dramatically as it is heated to this transition temperature but then falls and remains fairly constant for the ? form regardless of temperature.HP Pavilion DV4-1002TU Battery

Similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but is metastable at ambient pressures. This phase is usually hexagonal (ideal) or trigonal (distorted) and can be viewed as being due to a soft longitudinal acoustic phonon of the ? phase causing collapse of (111) planes of atoms.HP Pavilion DV4-1002TX Battery

Chemical properties

he most noted chemical property of titanium is its excellent resistance to corrosion; it is almost as resistant as platinum, capable of withstanding attack by dilute sulfuric acidand hydrochloric acid as well as chlorine gas, chloride solutions, and most organic acids.[3] However, it is soluble in concentrated acids.HP Pavilion DV4-1003AX Battery

The Pourbaix diagram in the image shows that titanium is actually thermodynamically a very reactive metal.

However, it is slow to react with water and air, because it forms a passive and protective oxide coating that protects it from further reaction.HP Pavilion DV4-1003TU Battery

When it first forms, this protective layer is only 1–2 nm thick but continues to slowly grow; reaching a thickness of 25 nm in four years.[15]

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.

HP Pavilion DV4-1003TX Battery

As a result, the metal cannot be melted in open air since it burns before the melting point is reached. Melting is only possible in an inert atmosphere or in a vacuum. At 550 °C (1,022 °F), it combines with chlorine.[3] It also reacts with the other halogens and absorbs hydrogen.HP Pavilion DV4-1004AX Battery

Titanium 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.[16]

Experiments have shown that natural titanium becomes radioactive after it is bombarded with deuterons, emitting mainlypositrons and hard gamma rays.HP Pavilion DV4-1004TU Battery

Compounds

The +4 oxidation state dominates titanium chemistry,[17] but compounds in the +3 oxidation state are also common.[18] Because of this high oxidation state, many titanium compounds have a high degree of covalent bonding.HP Pavilion DV4-1004TX Battery

Star sapphires and rubies get their asterism from the titanium dioxide impurities present in them.[15]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.HP Pavilion DV4-1005TX Battery

Esters of titanium are formed by the reaction of alcohols and titanium tetrachloride and are used to waterprooffabrics.[7]

Titanium nitride (TiN), having a hardness equivalent to sapphire and carborundum (9.0 on the Mohs Scale),[19] is often used to coat cutting tools, such as drill bits.HP Pavilion DV4-1006TX Battery

It also finds use as a gold-colored decorative finish, and as a barrier metal in semiconductor fabrication.[21]

Titanium tetrachloride (titanium(IV) chloride, TiCl4, sometimes called "tickle"[22]) is a colorless liquid which is used as an intermediate in the manufacture of titanium dioxide for paint.HP Pavilion DV4-1007TX Battery

It is widely used in organic chemistry as a Lewis acid, for example in the Mukaiyama aldol condensation.[24] Titanium also forms a lower chloride, titanium(III) chloride (TiCl3), which is used as a reducing agent.[25]

Titanocene dichloride is an important catalyst for carbon-carbon bond formation. Titanium isopropoxide is used for Sharpless epoxidation.HP Pavilion DV4-1008TX Battery

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).[4]

Occurrence

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)[27] and the seventh-most abundant metal.HP Pavilion DV4-1009TX Battery

It is present in most igneous rocks and insediments derived from them (as well as in living things and natural bodies of water).[2][3]Of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium.[27] Its proportion in soils is approximately 0.5 to 1.5%.HP Pavilion DV4-1010TX Battery

It is widely distributed and occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile,titanite (sphene), as well in many iron ores.[15] Of these minerals, only rutile and ilmenite have any economic importance, yet even they are difficult to find in high concentrations.HP Pavilion DV4-1011TX Battery

Significant titanium-bearing ilmenite deposits exist in western Australia, Canada, China, India, Mozambique, New Zealand, Norway, and Ukraine.[15]Large quantities of rutile are also mined in North America and South Africa and help contribute to the annual production of 90,000 tonnes of the metal and 4.3 million tonnes of titanium dioxide.HP Pavilion DV4-1012TX Battery

Total reserves of titanium are estimated to exceed 600 million tonnes.[15]

Titanium is contained in meteorites and has been detected in the sun and in M-type stars;[3] the coolest type of star with a surface temperature of 3,200 °C (5,790 °F).[28] Rocks brought back from the moon during the Apollo 17 mission are composed of 12.1% TiO2.[3] It is also found in coal ash, plants, and even the human body.HP Pavilion DV4-1013TX Battery

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).HP Pavilion DV4-1014NR Battery

Elevenradioisotopes 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.HP Pavilion DV4-1014TX Battery

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, iselectron 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.HP Pavilion DV4-1015TX Battery

Titanium was discovered included in a mineral in Cornwall, United Kingdom, in 1791 by amateur geologist and pastor William Gregor, then vicar of Creed parish.[29] He recognized the presence of a new element in ilmenite[4] when he found black sand by a stream in the nearbyparish of Manaccan and noticed the sand was attracted by a magnet.HP Pavilion DV4-1015TX Battery

Analysis of the sand determined the presence of two metal oxides;iron oxide (explaining the attraction to the magnet) and 45.25% of a white metallic oxide he could not identify.[27] 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.[HP Pavilion DV4-1016TX Battery

Around the same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it.[4] The oxide was independently rediscovered in 1795 by German chemist Martin Heinrich Klaproth in rutile from Hungary.[29] Klaproth found that it contained a new element and named it for the Titans of Greek mythology.HP Pavilion DV4-1017TX Battery

After hearing about Gregor's earlier discovery, he obtained a sample of manaccanite and confirmed it contained titanium.

The processes required to extract titanium from its various ores are laborious and costly; it is not possible to reduce in the normal manner, by heating in the presence of carbon, because that produces titanium carbide.HP Pavilion DV4-1018TX Battery

Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter at Rensselaer Polytechnic Institute by heating TiCl4with sodium at 700–800 °C in the Hunter process.[3] Titanium metal was not used outside the laboratory until 1932 when William Justin Kroll proved that it could be produced by reducing titanium tetrachloride (TiCl4) with calcium.HP Pavilion DV4-1019TX Battery

Eight years later he refined this process by using magnesium and even sodium in what became known as the Kroll process.[30]Although research continues into more efficient and cheaper processes (e.g., FFC Cambridge), the Kroll process is still used for commercial production.HP Pavilion DV4-1020TX Battery

Titanium of very high purity was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide, or crystal bar, process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal.HP Pavilion DV4-1020US Battery

In the 1950s and 1960s the Soviet Union pioneered the use of titanium in military and submarine applications (Alfa Class and Mike Class)[32] as part of programs related to the Cold War.[33] 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 andLockheed A-12.HP Pavilion DV4-1021TX Battery

In the USA, the Department of Defense realized the strategic importance of the metal[34] and supported early efforts of commercialization.[35] 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.HP Pavilion DV4-1022TX Battery

Today, the world's largest producer, Russian-based VSMPO-Avisma, is estimated to account for about 29% of the world market share.[37]

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.HP Pavilion DV4-1023TX Battery

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.HP Pavilion DV4-1024TX Battery

Production and fabrication

The processing of titanium metal occurs in 4 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.HP Pavilion DV4-1025TX Battery

Titanium Sponge is only produced in 7 countries by 19 companies.

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.HP Pavilion DV4-1026TX Battery

(The relatively high market value of titanium is mainly due to its processing, which sacrifices another expensive metal, magnesium. ) In the Kroll process, the oxide is first converted to chloride through carbochlorination, whereby chlorine gas is passed over red-hot rutile or ilmenite in the presence of carbon to make TiCl4.HP Pavilion DV4-1027TX Battery

This is condensed and purified by fractional distillation and then reduced with 800 °C molten magnesium in an argon atmosphere.

A more recently developed method, the FFC Cambridge process, 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.HP Pavilion DV4-1028TX Battery

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.HP Pavilion DV4-1028US Battery

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.HP Pavilion DV4-1029TX Battery

2 FeTiO3 + 7 Cl2 + 6 C ? 2 TiCl4 + 2 FeCl3 + 6 CO (900 °C)
TiCl4 + 2 Mg ? 2 MgCl2 + Ti (1100 °C)

About 50 grades of titanium and titanium alloys are designated and currently used, although only a couple of dozen are readily available commercially.HP Pavilion DV4-1030EE Battery

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%).HP Pavilion DV4-1030EI Battery

The remaining grades are alloys, each designed for specific purposes, be it ductility, strength, hardness, electrical resistivity, creep resistance, resistance to corrosion from specific media, or a combination thereof.HP Pavilion DV4-1030EJ Battery

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.HP Pavilion DV4-1030EN Battery

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. Contamination will cause a variety of conditions, such as embrittlement, which will reduce the integrity of the assembly welds and lead to joint failure.HP Pavilion DV4-1030TX Battery

Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account the fact that the metal has a "memory" and tends to spring back. This is especially true of certain high-strength alloys. Titanium cannot be soldered without first pre-plating it in a metal that is solderable.HP Pavilion DV4-1031TX Battery

The metal can be machined using the same equipment and via the same processes as stainless steel.[11]

Applications

Titanium is used in steel as an alloying element (ferro-titanium) to reduce grain size and as a deoxidizer, and in stainless steelto reduce carbon content.HP Pavilion DV4-1032TX Battery

Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron,manganese, molybdenum, and with other metals.[51] Applications for titanium mill products (sheet, plate, bar, wire, forgings, castings) can be found in industrial, aerospace, recreational, and emerging markets.HP Pavilion DV4-1033TX Battery

Powdered titanium is used in pyrotechnics as a source of bright-burning particles.

Pigments, additives and coatings

About 95% of titanium ore extracted from the Earth is destined for refinement into titanium dioxide (TiO2), an intensely white permanent pigment used in paints, paper, toothpaste, and plastics.HP Pavilion DV4-1034TX Battery

It is also used in cement, in gemstones, as an optical opacifier in paper,[53] and a strengthening agent in graphite composite fishing rods and golf clubs.

TiO2 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.HP Pavilion DV4-1035LA Battery

In nature, this compound is found in the minerals anatase, brookite, and rutile.[2] Paint made with titanium dioxide does well in severe temperatures, is somewhat self-cleaning , and stands up to marine environments.[4] Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond.HP Pavilion DV4-1035TX Battery

In addition to being a very important pigment, titanium dioxide is also used in sunscreens due to its ability to protect skin by itself.[9] Recently, titanium oxide has been put to use in air purifiers (as a filter coating), or in film used to coat windows on buildings so that when titanium oxide becomes exposed to UV lightHP Pavilion DV4-1036TX Battery

(either solar or artificial) and moisture in the air, reactive redox species like hydroxyl radicals are produced so that they can purify the air or keep window surfaces clean.[54]

Aerospace and marine

Due to their high tensile strength to density ratio,[7] high corrosion resistance,[3] fatigue resistance, high crack resistance,[HP Pavilion DV4-1037TX Battery

and ability to withstand moderately high temperatures without creeping, titanium alloys are used in aircraft,armor plating, naval ships, spacecraft, and missiles. For these applications titanium alloyed with aluminium, vanadium, and other elements is used for a variety of components including critical structural parts,HP Pavilion DV4-1038TX Battery

fire walls, landing gear, exhaust ducts (helicopters), and hydraulic systems. In fact, about two thirds of all titanium metal produced is used in aircraft engines and frames.[56] The SR-71 "Blackbird" was one of the first aircraft to make extensive use of titanium within its structure, paving the way for its use in modern military and commercial aircraft.HP Pavilion DV4-1039TX Battery

An estimated 59 metric tons (130,000 pounds) are used in the Boeing 777, 45 in theBoeing 747, 18 in the Boeing 737, 32 in the Airbus A340, 18 in the Airbus A330, and 12 in the Airbus A320. The Airbus A380 may use 146 metric tons, including about 26 tons in the engines.HP Pavilion DV4-1040EE Battery

In engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles. The titanium 6AL-4Valloy accounts for almost 50% of all alloys used in aircraft applications.[58]

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;HP Pavilion DV4-1040EI Battery

in heater-chillers for salt water aquariums, fishing line and leader, and for divers' knives. Titanium is used to manufacture the housings and other components of ocean-deployed surveillance and monitoring devices for scientific and military use. The former Soviet Union developed techniques for making submarines largely out of titanium.[HP Pavilion DV4-1040TX Battery

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 hydrometallurgyapplications due to their high strength (e. g.: titanium Beta C alloy), corrosion resistance, or combination of both.HP Pavilion DV4-1041TX Battery

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).[60] Other applications include: ultrasonic welding, wave soldering,[61] and sputtering targets.HP Pavilion DV4-1042TX Battery

Titanium tetrachloride (TiCl4), a colorless liquid, is important as an intermediate in the process of making TiO2 and is also used to produce the Ziegler-Natta catalyst, and is used to iridize glass and because it fumes strongly in moist air it is also used to make smoke screens.HP Pavilion DV4-1043TX Battery

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.HP Pavilion DV4-1044TX Battery

The metal is generally too expensive to make it marketable to the general consumer market, other than high-end products, particularly for the racing/performance market. Late model Corvettes have been available with titanium exhausts.HP Pavilion DV4-1045TX Battery

Titanium is used in many sporting goods: tennis rackets, golf clubs, lacrosse stick shafts; cricket, hockey, lacrosse, and football helmet grills; and bicycle frames and components. Although not a mainstream material for bicycle production, titanium bikes have been used by race teams and adventure cyclists.HP Pavilion DV4-1046TX Battery

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.HP Pavilion DV4-1047TX Battery

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 byfarriers, since it is lighter and more durable than steel when formed into horseshoes.HP Pavilion DV4-1048TX Battery

A titanium spork useful for backpackers. About 16 grams, lighter than a steel utensil but stronger than a plastic implement.

Titanium has occasionally been used in architectural applications: the 40 m (131 foot) memorial to Yuri Gagarin, the first man to travel in space, in Moscow, is made of titanium for the metal's attractive color and association with rocketry.HP Pavilion DV4-1049TX Battery

The Guggenheim Museum Bilbaoand the Cerritos Millennium Library were the first buildings in Europe and North America, respectively, to be sheathed in titanium panels.[56] Other construction uses of titanium sheathing include the Frederic C. Hamilton Building in Denver, Colorado and the 107 m (350 foot) Monument to the Conquerors of Space in Moscow.HP Pavilion DV4-1050 Battery

Because of its superior strength and light weight when compared to other metals traditionally used in firearms (steel, stainless steel, and aluminium), and advances in metalworking techniques, the use of titanium has become more widespread in the manufacture of firearms. Primary uses include pistol frames and revolver cylinders.

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For these same reasons, it is also used in the body of laptop computers (for example, in Apple's PowerBook line).

Some upmarket categories of tools made to be lightweight and corrosion-resistant, such as shovels and flashlights, are made of titanium or titanium alloys as well.HP Pavilion DV4-1051TX Battery

Jewelry

Because of its durability, titanium has become more popular for designer jewelry (particularly,titanium rings).[66] 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.HP Pavilion DV4-1052 Battery

Titanium is also alloyed with gold to produce an alloy that can be marketed as 24-carat gold, as the 1% of alloyed Ti is insufficient to require a lesser mark. The resulting alloy is roughly the hardness of 14-carat gold and thus is more durable than a pure 24-carat gold item would be.HP Pavilion DV4-1052TX Battery

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

The inertness and ability to be attractively colored makes titanium a popular metal for use in body piercing.HP Pavilion DV4-1053 Battery

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

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.HP Pavilion DV4-1053TX Battery

The titanium is often alloyed with about 4% aluminium  or 6% Al and 4% vanadium.

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.HP Pavilion DV4-1054TX Battery

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.HP Pavilion DV4-1055TX Battery

However, titanium alloys' stiffness is still more than twice that of bone so adjacent bone bears a greatly reduced load and may deteriorate.

Since titanium is non-ferromagnetic, patients with titanium implants can be safely examined with magnetic resonance imaging(convenient for long-term implants).HP Pavilion DV4-1070 Battery

Preparing titanium for implantation in the body involves subjecting it to a high-temperatureplasma arc which removes the surface atoms, exposing fresh titanium that is instantly oxidized.

Titanium is also used for the surgical instruments used in image-guided surgery, as well as wheelchairs, crutches, and any other products where high strength and low weight are desirable.HP Pavilion DV4-1070EE Battery

Precautions

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.HP Pavilion DV4-1070EF Battery

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.HP Pavilion DV4-1070ER Battery

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.HP Pavilion DV4-1070ES Battery

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. A fire hazard exists even when titanium is used in wet chlorine due to possible unexpected drying brought about by extreme weather conditions.HP Pavilion DV4-1080EI Battery

Titanium can catch fire when a fresh, non-oxidized surface comes 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.HP Pavilion DV4-1080EO Battery

Titanium rings are jewelry rings or bands which have been primarily constructed from titanium. The actual compositions of titanium can vary, such as "commercial pure" (99.2% titanium) or "aircraft grade" (primarily, 90% titanium, 6% aluminum, 4% vanadium),HP Pavilion DV4-1080ES Battery

and titanium rings are often crafted in combination with other materials, such as gemstones and traditional jewelry metals. Even with these variations in composition and materials, titanium rings are commonly referred to as such if they contain any amount of titanium.HP Pavilion DV4-1090EO Battery

Rings crafted from titanium are a modern phenomenon, becoming widely available on the market around the 1990s. Titanium rings offer several unique properties: they are biocompatible (hypoallergenic), lightweight, corrosion-resistant, and have the highest strength-to-weight ratio of any metal.HP Pavilion DV4-1090ES Battery

Titanium was discovered in Cornwall, England, in 1791 by William Gregor. It was also discovered around the same time by Hungarian mineralogist Franz-Joseph Müller von Reichenstein, and later in 1795 by German chemist Martin Heinrich Klaproth – the latter of which gave titanium its name, after the Titans of Greek mythology.HP Pavilion DV4-1100 Battery

However, it was not until after 1932 that commercial use for titanium became possible, due to methods established by William Justin Kroll. Kroll devised ways of reducing titanium tetrachloride (TiCl4) into its metal form.[3] His process is still used today for commercially-produced titanium.HP Pavilion DV4-Battery

The value of titanium rings can be very high. This is ostensibly because the process of extracting titanium from its various ores is laborious and costly.[2]Although it is indeed expensive as an engineering material, it is still cheaper than the jeweller's usual precious metals, even silver.HP Pavilion DV4-1101 Battery

It is unknown who first crafted titanium into a ring or other jewelry piece. Titanium started appearing on the open market in approximately the 1990s. Since 2000, availability of titanium rings has become large-scale, with most online and bricks-and-mortar jewelry stores likely to carry titanium-based rings as part of their inventory.HP Pavilion DV4-1101TU Battery

Many outlets now specialize exclusively in the design and sale of titanium rings.

Construction

Titanium rings are constructed using solid bars, tubes or sheets of titanium, which are cut into the desired shape and size of a ring. The metal can be machined using the same equipment and via the same engineering processes as stainless steel.HP Pavilion DV4-1101TX Battery

The usual jewelry-making techniques of rolling and soldering are not practical for titanium.

Properties

Titanium has become popular as a jewelry material due to its various unique properties. Titanium is biocompatible (often referred to as hypoallergenic), or non-toxic to the human body.HP Pavilion DV4-1102 Battery

Similarly, titanium rings will not react with wearers who suffer allergies to other jewelry materials.

It is highly resistant to most causes of corrosion, including sea water, aqua regia, chlorine (in water), and some acids. It is soluble in concentrated acids, however.HP Pavilion DV4-1102TU Battery

Titanium rings are therefore practical for those who regularly swim in the ocean or chlorinated pools, for example. This is in contrast to some traditional jewelry materials, such as silver, brass and bronze, which are prone to tarnishing and other manifestations of deterioration.HP Pavilion DV4-1102TX Battery

Titanium rings, depending on composition, have varying degrees of fatigue resistance and tensile strength. However, almost all well-known compositions feature higher fatigue resistance, as well as strength-to-weight ratios, than most – if not all - known metals.

Titanium rings are almost impossible to resize.HP Pavilion DV4-1103TU Battery

They are only slightly more difficult to cut off in case of emergency than for gold rings; titanium is comparable tosteel in its resistance to sawing.

Anodization

Anodization of titanium rings is the process whereby an oxide film is formed on the surface of the titanium via an electrolytic process to create color.HP Pavilion DV4-1103TX Battery

In the case of titanium rings, this process is performed after it is machined into shape. Oxidation changes the ordinary titanium color (generally silver, depending on composition and processing) and increases corrosion-resistance. The anodization process is extremely simple to carry out:HP Pavilion DV4-1104TU Battery

the piece is immersed in an electrolyte,cola is popularly used, and a DC voltage, around 100V, is applied. The voltage controls the thickness, and thus the colour, of the anodization.

Dyes are not necessary in the anodization of titanium. The color that results on a titanium ring depends on the thickness of the oxide coating, which is determined by the anodizing voltage.HP Pavilion DV4-1104TX Battery

The image to the left shows the color spectrum range that can be achieved via anodization. The colors, which are simply different wavelengths of light, arise from constructive interferencebetween the light reflected from the surface of the oxide layer and light reflected from the metal surface below.HP Pavilion DV4-1105EF Battery

Titanium compositions

Titanium can be alloyed with many other metals to enhance or alter titanium's properties. The most common alloy partners for titanium are aluminum, vanadium, iron, molybdenum and copper. Each alters titanium's properties for various purposes – for example, copper can be used to harden titanium.HP Pavilion DV4-1105EM Battery

One of the most common compositions for titanium rings is known as "aircraft grade" (also referred to as 6AL-4V or 6-4) titanium, because the composition is famous for its use in aircraft construction (however, it is also used for medical, marine and chemical processing purposes).HP Pavilion DV4-1105TU Battery

It is a blend of 6% aluminum, 4% vanadium and 90% titanium (as well as trace amounts of iron and oxygen; max 0.25% and 0.2% respectively), and is one of the strongest and most lightweight of other known compositions. Aircraft grade titanium is often used in crafting titanium rings due to its advantageous and suitable properties (compared with other titanium compositions), as well as its wide commercial availability.HP Pavilion DV4-1105TX Battery

Inlays

Inlays are the result of combining or joining two or more metals into one ring. It is not to be confused with alloying. The process of inlaying involves crushing the metals into channels, which are then trapped under pressure. On a ring, this usually results in metals sitting side-by-side on the surface – for example, a strip of gold running through the middle of an otherwise titanium ring.HP Pavilion DV4-1106EE Battery

The purpose of inlays are to enable the various metals within a titanium ring to be visibly distinguishable.

Classic

Titanium ring styles referred to as "classic" have generally been crafted into a simple oval or circle with a smooth, shiny finish. Besides ordinary machining, no external techniques or equipment are used in its production.HP Pavilion DV4-1106EM Battery

Mokume-gane

Mokume-gane gives titanium rings the appearance of wood-grain. It is a Japanese (also early Medieval European) forging technique that was applied to Samurai swords in the 17th century. It required great skill on the part of the smith; though modern process today, such as controlled atmospheres and temperature-controlled furnaces make the technique easier to achieve.HP Pavilion DV4-1106TX Battery

Titanium nitride (TiN) (sometimes known as “Tinite” or “TiNite” or “TiN”) is an extremely hard ceramic material, often used as a coating on titanium alloys, steel, carbide, and aluminium components to improve the substrate's surface properties.HP Pavilion DV4-1107TX Battery

Applied as a thin coating, TiN is used to harden and protect cutting and sliding surfaces, for decorative purposes (due to its gold appearance), and as a non-toxic exterior for medical implants. In most applications a coating of less than 5 micrometres (0.00020 in) is applied.HP Pavilion DV4-1108TX Battery

TiN will oxidize at 800 °C at normal atmosphere. It is chemically stable at room temperature and is attacked by hot concentrated acids.[1]

TiN has excellent infrared (IR) reflectivity properties, reflecting in a spectrum similar to elemental gold (Au), which gives it a yellowish color.HP Pavilion DV4-1109TX Battery

Depending on the

substrate material and surface finish, TiN will have a coefficient of friction ranging from 0.4 to 0.9 versus itself (non-lubricated). Typical formation has a crystal structure of NaCl-type with a roughly 1:1stoichiometry; however TiNx compounds with x ranging from 0.6 to 1.2 are thermodynamically stable.HP Pavilion DV4-1110EO Battery

A thin film of titanium nitride was chilled to near absolute zero converting it into the first known superinsulator, with resistance suddenly increased by a factor of 100,000.

A well-known use for TiN coating is for edge retention and corrosion resistance on machine tooling, such asdrill bits and milling cutters, often improving their lifetime by a factor of three or more.HP Pavilion DV4-1110TX Battery

Because of TiN's metallic gold color, it is used to coat costume jewelry and automotive trim for decorative purposes. TiN is also widely used as a top-layer coating, usually with nickel (Ni) or chromium (Cr) plated substrates, on consumer plumbing fixtures and door hardware.HP Pavilion DV4-1111TX Battery

As a coating it is used in aerospace and military applications and to protect the sliding surfaces ofsuspension forks of bicycles and motorcycles as well as the shock shafts of radio controlled cars. TiN is non-toxic, meets FDAguidelines and has seen use in medical devices such as scalpel blades and orthopedic bone saw blades where sharpness and edge retention are important.HP Pavilion DV4-1112TX Battery

TiN coatings have also been used in implanted prostheses (especially hip replacement implants) and other medical implants.

Though less visible, thin films of TiN are also used in microelectronics, where they serve as conductive barrier between the active device and the metal contacts used to operate it.HP Pavilion DV4-1113TX Battery

While the film blocks diffusion of metal into the silicon, it is conductive enough (30–70 ??·cm) to allow a good electrical connection. In this context, TiN is classified as a "barrier metal", even though it is clearly a ceramic from the perspective of chemistry or mechanical behavior.HP Pavilion DV4-1114NR Battery

Recent chip design in the 45 nm technology and beyond also makes use of TiN as a metal material for improved transistor performance. In combination withgate dielectrics (e.g. HfSiO) that have a higher permittivity compared to standard SiO2 the gate length can be scaled down with low leakage, higher drive current and same or better threshold voltage.HP Pavilion DV4-1114TX Battery

Due to their high biostability, TiN layers may also be used as electrodes in bioelectronic applications [7] like in intelligentimplants or in-vivo biosensors that have to withstand the severe corrosion caused by the body fluid. TiN electrodes have already been applied in the subretinal prothesis project [8] as well as in biomedical microelectromechanical systems (BioMEMS).HP Pavilion DV4-1115EF Battery

Fabrication

The most common methods of TiN thin film creation are physical vapor deposition (PVD, usually sputter deposition, cathodic arc deposition or electron beam heating) and chemical vapor deposition (CVD). In both methods, pure titanium is sublimated and reacted with nitrogen in a high-energy, vacuum environment.HP Pavilion DV4-1115TX Battery

TiN film may also be produced on Ti workpieces by reactive growth (for example, annealing) in a nitrogen atmosphere. PVD is preferred for steel parts because the deposition temperatures exceeds the austenitizing temperature of steel. TiN layers are also sputtered on a variety of higher melting point materials such asstainless steels, titanium and titanium alloys.HP Pavilion DV4-1116TX Battery

Its high Young's modulus (values between 450 and 590 GPa have been reported in the literature [11]) means that thick coatings tend to flake away, making them much less durable than thin ones. Titanium nitride coatings can also be deposited by thermal spraying whereas TiN powders are produced by nitridation of titanium with nitrogen or ammonia at 1200 °C.HP Pavilion DV4-1117CA Battery

Bulk ceramic objects can be fabricated by packing powdered metallic titanium into the desired shape, compressing it to the proper density, then igniting it in an atmosphere of pure nitrogen. The heat released by the chemical reaction between the metal and gas is sufficient to sinter the nitride reaction product into a hard, finished item. See powder metallurgy.HP Pavilion DV4-1117TX Battery

Other commercial variants

There are several commercially-used variants of TiN that have been developed in the past decade, such as titanium carbon nitride (TiCN), titanium aluminium nitride (TiAlN or AlTiN), and titanium aluminum carbon nitride, which may be used individually or in alternating layers with TiN.HP Pavilion DV4-1118CA Battery

These coatings offer similar or superior enhancements in corrosion resistance and hardness, and additional colors ranging from light gray to nearly black, to a dark iridescent bluish-purple depending on the exact process of application. These coatings are becoming common on sporting goods, particularly knives and handguns, where they are used for both cosmetic and functional reasons.HP Pavilion DV4-1118TX Battery

As a constituent in steel making

Titanium nitride is also produced intentionally within some steels by judicious addition of titanium to the alloy. TiN forms at very high temperatures because of its very low enthalpy of formation, and even nucleates directly from the melt in secondary steelmaking.HP Pavilion DV4-1119TX Battery

It forms discrete, micrometre-sized cubic particles at grain boundaries and triple points, and prevents grain growth by Ostwald ripening up to very highhomologous temperatures. Titanium nitride has the lowest solubility product of any metal nitride or carbide in austenite, a useful attribute in microalloyed steelformulas.HP Pavilion DV4-1120BR Battery

Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO2. When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase.HP Pavilion DV4-1120TX Battery

It has a wide range of applications, from paint to sunscreen to food colouring. When used as a food colouring, it has E number E171.

Titanium dioxide occurs in nature as well-known minerals rutile, anatase and brookite, and additionally as two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic ?-PbO2-like form, both found recently at the Ries crater inBavaria.[HP Pavilion DV4-1120US Battery

The most common form is rutile,[3] which is also the equilibrium phase at all temperatures.[4] The metastableanatase and brookite phases both convert to rutile upon heating.[3][5] Rutile, anatase and brookite all contain six coordinated titanium.HP Pavilion DV4-1121BR Battery

Titanium dioxide has eight modifications – in addition to rutile, anatase and brookite there are three metastable forms produced synthetically (monoclinic, tetragonal and orthorombic), and five high pressure forms (?-PbO2-like, baddeleyite-like,cotunnite-like, orthorhombic OI, and cubic phases):HP Pavilion DV4-1121CA Battery

The cotunnite-type phase was claimed by L. Dubrovinsky and co-authors to be the hardest known oxide with the Vickers hardnessof 38 GPa and the bulk modulus of 431 GPa (i.e. close to diamond's value of 446 GPa) at atmospheric pressure.HP Pavilion DV4-1121TX Battery

However, later studies came to different conclusions with much lower values for both the hardness (7–20 GPa, which makes it softer than common oxides like corundum Al2O3 and rutile TiO2) [14] and bulk modulus (~300 GPa) .

The naturally occurring oxides can be mined and serve as a source for commercial titanium.HP Pavilion DV4-1122TX Battery

The metal can also be mined from other minerals such as ilmenite or leucoxene ores, or one of the purest forms, rutile beach sand. Star sapphires and rubiesget their asterism from rutile impurities present in them.[17]

Titanium dioxide (B) is found as a mineral in magmatic rocks and hydrothermal veins, as well as weathering rims onperovskite. TiO2also forms lamellae in other minerals.HP Pavilion DV4-1123LA Battery

Spectral lines from titanium oxide are prominent in class M stars, which are cool enough to allow molecules of this chemical to form.

Production

Crude titanium dioxide is purified via converting to titanium tetrachloride in the chloride process.HP Pavilion DV4-1123TX Battery

In this process, the crude ore (containing at least 70% TiO2) is reduced with carbon, oxidized with chlorine to give titanium tetrachloride; i.e., carbothermal chlorination. This titanium tetrachloride is distilled, and re-oxidized in a pure oxygen flame or plasma at 1500–2000 K to give pure titanium dioxide while also regenerating chlorine.HP Pavilion DV4-1123US Battery

Aluminium chloride is often added to the process as a rutile promotor; the product is mostly anatase in its absence.

Another widely used process utilizes ilmenite as the titanium dioxide source, which is digested in sulfuric acid. The by-product iron(II) sulfate is crystallized and filtered-off to yield only the titanium salt in the digestion solution, which is processed further to give pure titanium dioxide.HP Pavilion DV4-1124LA Battery

Another method for upgrading ilmenite is called the Becher Process. One method for the production of titanium dioxide with relevance to nanotechnology is solvothermal Synthesis of titanium dioxide.

Nanotubes

Anatase can be converted by hydrothermal synthesis to delaminated anatase inorganic nanotubes  and titanate nanoribbonswhich are of potential interest as catalytic supports and photocatalysts.HP Pavilion DV4-1124NR Battery

In the synthesis, anatase is mixed with 10 M sodium hydroxide and heated at 130 °C for 72 hours. The reaction product is washed with dilute hydrochloric acid and heated at 400 °C for another 15 hours. The yield of nanotubes is quantitative and the tubes have an outer diameter of 10 to 20 nm and an inner diameter of 5 to 8 nm and have a length of 1 ?m.HP Pavilion DV4-1124TX Battery

A higher reaction temperature (170 °C) and less reaction volume gives the corresponding nanowires.

Another process for synthesizing TiO2 is through Anodization in an electrolytic solution. When anodized in a 0.5 weight percent HF solution for 20 minutes, well-aligned titanium oxide nanotube arrays can be fabricated an average tube diameter of 60 nm and length of 250 nm.HP Pavilion DV4-1125BR Battery

Based on X-ray Diffraction, nanotubes grown through anodization are amorphous.

Titanium dioxide is the most widely used white pigment because of its brightness and very high refractive index (n = 2.7), in which it is surpassed only by a few other materials. Approximately 4 million tons of pigmentary TiO2 are consumed annually worldwide.HP Pavilion DV4-1125LA Battery

When deposited as a thin film, its refractive index and colour make it an excellent reflective optical coating for dielectric mirrors and some gemstones like "mystic fire topaz". TiO2 is also an effective opacifier in powder form, where it is employed as a pigment to provide whiteness and opacity to products such as paints, coatings, plastics, papers, inks, foods, medicines (i.e. pills and tablets) as well as most toothpastes.HP Pavilion DV4-1125NR Battery

In paint, it is often referred to offhandedly as "the perfect white", "the whitest white", or other similar terms. Opacity is improved by optimal sizing of the titanium dioxide particles.

In ceramic glazes titanium dioxide acts as an opacifier and seeds crystal formation.HP Pavilion DV4-1125TX Battery

Titanium dioxide is often used to whiten skimmed milk; this has been shown statistically to increase skimmed milk's palatability.[23]

Titanium dioxide is used to mark the white lines on the tennis courts of the All England Lawn Tennis and Croquet Club, best known as the venue for the annual grand slam tennis tournament The Championships, Wimbledon.HP Pavilion DV4-1126LA Battery

The exterior of the Saturn V rocket was painted with titanium dioxide; this later allowed astronomers to determine that J002E3 was the S-IVB stage from Apollo 12 and not an asteroid.

Sunscreen and UV absorber

In cosmetic and skin care products, titanium dioxide is used as a pigment, sunscreen and a thickener.HP Pavilion DV4-1126TX Battery

It is also used as a tattoo pigment and in styptic pencils. Titanium dioxide is produced in varying particle sizes, oil and water dispersible, and with varying coatings for the cosmetic industry. This pigment is used extensively in plastics and other applications for its UV resistant properties where it acts as a UV absorber, efficiently transforming destructive UV light energy into heat.HP Pavilion DV4-1127LA Battery

Titanium dioxide is found in almost every sunscreen with a physical blocker because of its high refractive index, its strong UV light absorbing capabilities and its resistance to discolouration under ultraviolet light. This advantage enhances its stability and ability to protect the skin from ultraviolet light.HP Pavilion DV4-1127TX Battery

Sunscreens designed for infants or people with sensitive skin are often based on titanium dioxide and/or zinc oxide, as these mineral UV blockers are believed to cause less skin irritation than other UV absorbing chemicals. The titanium dioxide particles used in sunscreens have to be coated with silica or alumina, because titanium dioxide creates radicals in the photocatalytic reaction.HP Pavilion DV4-1128TX Battery

These radicals are carcinogenic, and could damage the skin.

Photocatalyst

Titanium dioxide, particularly in the anatase form, is a photocatalyst under ultraviolet (UV) light. Recently it has been found that titanium dioxide, when spiked with nitrogen ions or doped with metal oxide like tungsten trioxide, is also a photocatalyst under either visible or UV light.HP Pavilion DV4-1129LA Battery

The strong oxidative potential of the positive holes oxidizes water to create hydroxyl radicals. It can also oxidize oxygen or organic materials directly. Titanium dioxide is thus added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing and anti-fouling properties and is used as a hydrolysis catalyst.HP Pavilion DV4-1129TX Battery

It is also used in dye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell).

The photocatalytic properties of titanium dioxide were discovered by Akira Fujishima in 1967 and published in 1972.  The process on the surface of the titanium dioxide was called the Honda-Fujishima effect.HP Pavilion DV4-1130BR Battery

Titanium dioxide has potential for use in energy production: as a photocatalyst, it can carry out hydrolysis; i.e., break water into hydrogen and oxygen. Were the hydrogen collected, it could be used as a fuel. The efficiency of this process can be greatly improved by doping the oxide with carbon.HP Pavilion DV4-1130TX Battery

Further efficiency and durability has been obtained by introducing disorder to the lattice structure of the surface layer of titanium dioxide nanocrystals, permitting infrared absorption.

Titanium dioxide can also produce electricity when in nanoparticle form. Research suggests that by using these nanoparticles to form the pixels of a screen, they generate electricity when transparent and under the influence of light.HP Pavilion DV4-1131BR Battery

If subjected to electricity on the other hand, the nanoparticles blacken, forming the basic characteristics of a LCD screen. According to creator Zoran Radivojevic, Nokia has already built a functional 200-by-200-pixel monochromatic screen which is energetically self-sufficient.HP Pavilion DV4-1131TX Battery

In 1995 Fujishima and his group discovered the superhydrophilicity phenomenon for titanium dioxide coated glass exposed to sun light.[26] This resulted in the development of self-cleaning glass and anti-fogging coatings.

TiO2 incorporated into outdoor building materials, such as paving stones in noxer blocks or paints, can substantially reduce concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides.HP Pavilion DV4-1132TX Battery

A photocatalytic cement that uses titanium dioxide as a primary component, produced by Italcementi Group, was included in Time's Top 50 Inventions of 2008.

TiO2 offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors.HP Pavilion DV4-1133TX Battery

  1. The process occurs under ambient conditions very slowly; direct UV light exposure increases the rate of reaction.
  2. The formation of photocyclized intermediate products, unlike direct photolysis techniques, is avoided.
  3. Oxidation of the substrates to CO2 is complete.HP Pavilion DV4-1134TX Battery
  1. The photocatalyst is inexpensive and has a high turnover.
  2. TiO2 can be supported on suitable reactor substrates.

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