7440-32-6 Usage
History, Occurrence and Uses
Titanium was discovered in 1790 by English chemist William Gregor. Five years later in 1795, Klaproth confirmed Gregor’s findings from his independent investigation and named the element titanium after the Latin name Titans, the mythical first sons of the Earth. The metal was prepared in impure form first by Nilson and Pettersson in 1887. Hunter, in 1910, prepared the metal in pure form by reducing titanium tetrachloride with sodium.
Titanium occurs in nature in the minerals rutile( TiO2), ilmenite (FeTiO3), geikielite, (MgTiO3) perovskite (CaTiO3) and titanite or sphene (CaTiSiO4(O,OH,F)). It also is found in many iron ores. Abundance of titanium in the earth’s crust is 0.565%. Titanium has been detected in moon rocks and meteorites. Titanium oxide has been detected in the spectra of M-type stars and interstellar space.
Titanium is found in plants, animals, eggs, and milk.
Many titanium alloys have wide industrial applications. Titanium forms alloys with a number of metals including iron, aluminum, manganese, and molybdenum. Its alloys are of high tensile strength, lightweight, and can withstand extreme temperatures. They are used in aircraft and missiles. The metal also has high resistance to sea water corrosion and is used to protect parts of the ships exposed to salt water. Also, titanium is used to combine with and remove traces of oxygen and nitrogen from incandescent lamps. Titanium compounds, notably the dioxide and the tetrachloride, have many uses (See Titanium Dioxide and Titanium Tetrachloride.)
Physical Properties
White lustrous metal; ductile when free of oxygen; low density high strength metal.
Titanium has two allotropic modifications: (1) alpha form and (2) beta modification. The alpha form has a close-packed hexagonal crystal structure; density 4.54 g/cm3 at 20°C and stable up to 882°C. It converts very slowly to a body-centered cubic beta form at 882°C. The density of the beta form is 4.40 g/cm3 at 900°C (estimated). The other physical properties are as follows: The metal melts at 1,610 ±10°C; vaporizes at 3,287°C; electrical resitivity 42 microhm-cm; modulus of elasticity 15.5x106 psi at 25°C; tensile strength, ultimate 34,000 psi (at 25°C); tensile strength yield 20,000 psi (at 25°C); Vickers hardness 80-100; surface tension at the melting point 1427dynes/cm3; superconductivity below 1.73°K; thermal neutron absorption cross section 5.8 barns; insoluble in water; soluble in dilute acids.
Production
The production of titanium always encounters difficulties because of a tendency to react with oxygen, nitrogen and moisture at elevated temperatures. Most high purity elemental titanium can be produced by the Kroll process from titanium tetrachloride. The tetrachloride is reduced with magnesium in a mild steel vessel at about 800°C under an inert atmosphere of helium or argon. The net reaction is as follows:
TiCl4 + 2Mg → Ti + 2 MgCl2
The reaction is highly exothermic providing heat needed to maintain high temperature required for reaction. The Kroll process is applied commercially to produce elemental titanium.
Sodium metal can be used instead of magnesium in thermally reducing titanium tetrachloride.
Titanium metal also can be produced by electrolytic methods. In electrolysis, fused mixtures of titanium tetrachloride or lower chlorides with alkaline earth metal chlorides are electrolyzed to produce metal. Also, pure titanium can be prepared from electrolysis of titanium dioxide in a fused bath of calcium-, magnesiumor alkali metal fluorides. Other alkali or alkaline metal salts can be substituted for halides in these fused baths. Other titanium compouds that have been employed successfully in electrolytic titanium production include sodium fluotitanate and potassium fluotitanate.
Very highly pure titanium metal can be prepared in small amounts by decomposition of pure titanium tetraiodide, (TiI4) vapor on a hot wire under low pressure (Van Arkel–de Boer method).
Reactions
Titanium metal is very highly resistant to corrosion. It is unaffected by atmospheric air, moisture and sea water, allowing many of its industrial applications. The metal burns in air at about 1,200°C incandescently forming titanium dioxide TiO2. The metal also burns on contact with liquid oxygen. Titanium forms four oxides, all of which have been well described. It forms a weakly basic monoxide, TiO; a basic dititanium trioxide, Ti2O3; the amphoteric dioxide, TiO2; and the acidic trioxide, TiO3.
Titanium combines with nitrogen at about 800°C forming the nitride and producing heat and light. It is one of the few elements that burns in nitrogen. Titanium reacts with all halogens at high temperatures. It reacts with fluorine at 150°C forming titanium tetrafluoride, TiF4. Reaction with chlorine occurs at 300°C giving tetrachloride TiCl4. Bromine and iodine combine with the metal at 360°C forming their tetrahalides.
Water does not react with Ti metal at ambient temperatures, but tianium reacts with steam at 700°C forming the oxide and hydrogen:
Ti + 2H2O → TiO2 + 2H2
Titanium is soluble in hot concentrated sulfuric acid, forming sulfate. It also reacts with hydrofluoric acid forming the fluoride.
Nitric acid at ordinary temperatures does not react with Ti metal, but hot concentrated nitric acid oxidizes titanium to titanium dioxide.
The metal is stable with alkalies.
Titanium combines with several metals, such as, iron, copper, aluminum, chromium, cobalt, nickel, lead and tin at elevated temperatures forming alloys.
Description
Titanium was discovered by the Reverend William Gregor in
1791, and is named after the ‘Titans’ of Greek mythology. The
metal was not isolated in a pure state until 1910, and useful
quantities were not available for industrial applications until
1946, when an economical purification process was developed.
Chemical Properties
Titanium is a silvery metal or dry, dark-gray amorphous, lustrous powder.
Physical properties
Positioned at the top of group 4 (IVB), titanium heads up a group of metals sometimesreferred to as the “titanium group.” Members of this group have some similar properties.Titanium’s density is 4.5 g/cm3, which makes it heavier than aluminum but not as heavy asiron. Its melting point is high at 1,660°C, and its boiling point is even higher at 3287°C.Titanium metal is harder than steel but much lighter and does not corrode in seawater,which makes it an excellent alloy metal for use in most environmental conditions. It is alsoparamagnetic, which means that it is not responsive to magnetic fields. It is not a very goodconductor of heat or electricity.
Isotopes
There are 23 known isotopes of titanium. All but five are radioactive, rangingfrom Ti-38 to Ti-61, and have half-lives varying from a few nanoseconds to a few hours.The percentages of the five stable isotopes found in nature are as follows: 46Ti = 8.25%,47Ti = 7.44%, 48Ti = 73.72%, 49Ti = 5.41%, and 50Ti = 5.18%.
Origin of Name
It was named after “Titans,” meaning the first sons of the Earth as
stated in Greek mythology.
Occurrence
Titanium is the ninth most abundant element found in the Earth’s crust, but not in pureform. It is found in two minerals: rutile, which is titanium dioxide (TiO2), and ilmenite(FeTiO3). It is also found in some iron ores and in the slag resulting from the productionof iron. The mineral rutile is the major source of titanium production in the United States.Although titanium is widely spread over the crust of the Earth, high concentrations of itsminerals are scarce. In the past it was separated from it ores by an expensive process ofchemical reduction that actually limited the amount of metal produced. A two-step processinvolves heating rutile with carbon and chlorine to produce titanium tetrachloride—TiO2+ C + 2Cl2 ?→ TiCl4 + CO2—which is followed by heating the titanium tetrachloridewith magnesium in an inert atmosphere: TiCl4 + 2Mg ?→ Ti + 2 MgCl2. As recently as theyear 2000, a method of electrolysis was developed using titanium tetrachloride in a bath ofrare-earth salts. This process can be used on a commercial scale that makes the productionof titanium much less expensive. Titanium was, and still is, a difficult element to extractfrom its ore.Titanium is found throughout the universe and in the stars, the sun, the moon, and themeteorites that land on Earth.
Characteristics
As the first element in group 4, titanium has characteristics similar to those of the othermembers of this group: Zr, Hf, and Rf. Titanium is a shiny, gray, malleable, and ductile metalcapable of being worked into various forms and drawn into wires.
History
In 1791 Reverend William Gregor (1761–1817), an amateur mineralogist, discoveredan odd black sandy substance in his neighborhood. Because it was somewhat magnetic, hecalculated that it was almost 50% magnetite (a form of iron ore). Most of the remainder ofthe sample was a reddish-brown powder he dissolved in acid to produce a yellow substance.Thinking he had discovered a new mineral, he named it “menachanite,” after the Menachanregion in Cornwall where he lived. During this period, Franz Joseph Muller (1740–1825) alsoproduced a similar substance that he could not identify. In 1793 Martin Heinrich Klaproth(1743–1817), who discovered several new elements and is considered the father of modernanalytical chemistry, identified the substance that Gregor called a mineral as a new element.Klaproth named it “titanium,” which means “Earth” in Latin.
Uses
Different sources of media describe the Uses of 7440-32-6 differently. You can refer to the following data:
1. Given titanium’s lightness, strength, and resistance to corrosion and high temperatures, itsmost common use is in alloys with other metals for constructing aircraft, jet engines, and missiles. Its alloys also make excellent armor plates for tanks and warships. It is the major metalused for constructing the stealth aircraft that are difficult to detect by radar.Titanium’s noncorrosive and lightweight properties make it useful in the manufacture oflaboratory and medical equipment that will withstand acid and halogen salt corrosion. Thesesame properties make it an excellent metal for surgical pins and screws in the repair of brokenbones and joints.It has many other uses as an abrasive, as an ingredient of cements, and as a paint pigmentin the oxide form and in the paper and ink industries, in batteries for space vehicles, andwherever a metal is needed to resist chlorine (seawater) corrosion.
2. As alloy with copper and iron in titanium bronze; as addition to steel to impart great tensile strength; to aluminum to impart resistance to attack by salt solutions and by organic acids; to remove traces of oxygen and nitrogen from incandescent lamps. Surgical aid (fracture fixation).
3. Titanium is added to steel and aluminumto enhance their tensile strength and acidresistance. It is alloyed with copper and ironin titanium bronze.
Production Methods
Titanium is the ninth most abundant element and accounts for about 0.63% of the Earth’s crust. Analyses of rock samples from the moon indicate that titanium is far more abundant there; some lunar rocks consist of 12% titanium by weight. World production of titanium sponge metal was estimated at 69,000 metric tons in 1991. The most important titaniumbearing minerals are ilmenite, rutile, and leucoxene. Ilmenite (FeTiO3) is found in beach sands (Australia, India, and Florida) and in rock deposits associated with iron (Norway and Finland). Ilmenite accounts for about 91%of the world’s consumption of titanium minerals and world resources of anatase, ilmenite, and rutile total more than 2 billion tons. Rutile (a form ofTiO2) is less abundant; its chief source is certain Australian beach sands. Two other less prominent forms of TiO2 exist, anatase and brookite. The ores vary around the world in TiO2 content from 39% to 96%. Anatase is used as a food color.
Definition
A silvery
transition metal that occurs in various ores
as titanium(IV) oxide and also in combination
with iron and oxygen. It is extracted
by conversion of titanium(IV) oxide to the
chloride, which is reduced to the metal by
heating with sodium. Titanium is reactive
at high temperatures. It is used in the aerospace
industry as it is strong, resistant to
corrosion, and has a low density. It forms
compounds with oxidation states +4, +3,
and +2, the +4 state being the most stable.
Symbol: Ti; m.p. 1660°C; b.p. 3287°C;
r.d. 4.54 (20°C); p.n. 22; r.a.m. 47.867.
General Description
TITANIUM is a gray lustrous powder. TITANIUM can be easily ignited and burns with an intense flame. The very finely powdered material may be ignited by sparks.
Air & Water Reactions
Highly flammable. Pyrophoric in dust form [Bretherick 1979, p. 104]. Titanium is water-reactive at 700C, releasing hydrogen, which may cause an explosion [Subref: Mellor, 1941, vol. 7, 19].
Reactivity Profile
TITANIUM reacts violently with cupric oxide and lead oxide when heated. When titanium is heated with potassium chlorate, potassium nitrate, or potassium permanganate, an explosion occurs [Mellor 7:20. 1946-47]. The residue from the reaction of titanium with red fuming nitric acid exploded violently when the flask was touched [Allison 1969]. Liquid oxygen gives a detonable mixture when combined with powdered titanium, [Kirchenbaum 1956].
Hazard
Almost all of titanium’s compounds, as well as the pure metal when in powder form, areextremely flammable and explosive. Titanium metal will ignite in air at 1200°C and willburn in an atmosphere of nitrogen. Titanium fires cannot be extinguished by using water orcarbon dioxide extinguishers. Sand, dirt, or special foams must be used to extinguish burningtitanium.
Health Hazard
Different sources of media describe the Health Hazard of 7440-32-6 differently. You can refer to the following data:
1. Inhalation of metal powder may cause coughing,irritation of the respiratory tract, anddyspnea. Intramuscular administration of titaniumin rats caused tumors in blood. Animalcarcinogenicity is not fully established.Human carcinogenicity is not known.
2. Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution.
Fire Hazard
Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated.
Flammability and Explosibility
Nonflammable
Safety Profile
Questionable
carcinogen with experimental tumorigenic
data. Experimental reproductive effects.
The dust may ignite spontaneously in air.
Flammable when exposed to heat or flame
or by chemical reaction. Titanium can burn
in an atmosphere of carbon dioxide,
nitrogen, or air. Also reacts violently with
BrF3, CuO, PbOx (Ni + KClO3), metaloxy
salts, halocarbons, halogens, CO2, metal
carbonates, Al, water, AgF, O2 , nitryl
fluoride, HNO3,O2, KClO3, KNO3 ,
KMnO4, steam @ 704°, trichloroethylene,
trichlorotrifluoroethane. Ordinary
extinguishers are often ineffective against
titanium fires. Such fires require special
extinguishers designed for metal fires. In
airtight enclosures, titanium fires can be
controlled by the use of argon or helium.
Titanium, in the absence of moisture, burns
slowly, but evolves much heat. The
application of water to burning titanium can
cause an explosion. Finely dwided titanium
dust and powders, like most metal powders,
are potential explosion hazards when
exposed to sparks, open flame, or high-heat
sources. See also TITANIUM
COMPOUNDS, POWDERED METALS,
and MAGNESIUM.
Potential Exposure
Titanium metal, because of its low weight, high strength, and heat resistance, is used in the aerospace and aircraft industry as tubing, fittings, fire walls; cowlings, skin sections; jet compressors; and it is also used in surgical appliances. It is used, too, as controlwire casings in nuclear reactors, as a protective coating for mixers in the pulp-paper industry and in other situations in which protection against chlorides or acids is required; in vacuum lamp bulbs and X-ray tubes; as an addition to carbon and tungsten in electrodes and lamp filaments; and to the powder in the pyrotechnics industry. It forms alloys with iron, aluminum, tin, and vanadium, of which ferrotitanium is especially important in the steel industry. Other titanium compounds are utilized in smoke screens, as mordants in dyeing; in the manufacture of cemented metal carbides; as thermal insulators; and in heat resistant surface coatings in paints and plastics.
Environmental Fate
Titanium is poorly absorbed by plants and animals and is
retained to only a certain extent. High levels of titanium in food
products can be detects, however, when soil is contaminated by
fly-ash fallout or titanium-containing sewage residues and
when titanium dioxide is used as a food whitener. Food, which
is considered to be the most important source of exposure to
titanium, contributes >99% of the daily intake of the element.
There are no relevant tolerable intakes for titanium against
which to compare estimated dietary intake. Typical diets may
contain approximately 0.3–0.5 mg titanium.
Titanium content of soil generally ranges from 0.3 to 6%,
high levels of which are found in the vicinity of power plants
because of combustion of coal.
Titanium concentrations in the atmosphere are comparatively
low. Annual average concentrations in urban air are
mostly <0.1 mgm-3 and they are lower still in rural air. Air
concentrations up to 0.5 mgm-3 have been reported in urban
and industrialized areas.
Shipping
UN2546 Titanium powder, dry, Hazard Class: 4.2; Labels: 4.2-Spontaneously combustible material.
Toxicity evaluation
Many data indicate that titanium is absorbed poorly from the
gastrointestinal tract in human beings. It is likely that transferrin
may act as a specific carrier of titanium ions and may play
a central role during the transport and biodistribution of
soluble titanium species throughout the organism. Titanium
concentrations found generally in urine suggest an absorption
of <5%, assuming a daily intake of at least 300 mg.
Incompatibilities
Powder and dust may ignite spontaneously in air. Violent reactions occur on contact with water, steam, halocarbons, halogens, and aluminum. The dry powder is a strong reducing agent; Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause firesor explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.
Check Digit Verification of cas no
The CAS Registry Mumber 7440-32-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,4,4 and 0 respectively; the second part has 2 digits, 3 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 7440-32:
(6*7)+(5*4)+(4*4)+(3*0)+(2*3)+(1*2)=86
86 % 10 = 6
So 7440-32-6 is a valid CAS Registry Number.
InChI:InChI=1S/Ti
7440-32-6Relevant articles and documents
Titanium powder production by preform reduction process (PRP)
Okabe, Toru H.,Oda, Takashi,Mitsuda, Yoshitaka
, p. 156 - 163 (2004)
To develop an effective process for titanium powder production, a new preform reduction process (PRP), based on the calciothermic reduction of preform containing titanium oxide (TiO2), was investigated. The feed preform was fabricated from slurry, which was made by mixing TiO2 powder, flux (e.g. CaCl2) and binder. Various types of preforms in the form of plates, spheres, or tubes were prepared using a conventional technique, and the fabricated preform was sintered at 1073 K before reduction in order to remove the binder and water. The sintered solid preform containing TiO2 was then placed in a stainless steel container, and reacted with calcium vapor at a constant temperature ranging between 1073 and 1273 K for 6 h. Titanium powder was recovered from the reduced preform by leaching it with acid. As a result, pure titanium powder with 99 mass% purity was obtained. This process was found to be suitable for producing a homogeneous fine powder when the composition of flux and the size of the preform are controlled.
Revealing dehydrogenation effect and resultant densification mechanism during pressureless sintering of TiH2 powder
Chen,Yang,Liu,Ma,Kang,Wang,Zhang,Li,Li,Li
, (2021)
The use of TiH2 powder as a sintering precursor can produce nearly full-density titanium and titanium alloys with good mechanical properties. Unfortunately, there is a lack of research on the effect of lattice defects generated during the dehydrogenation of TiH2 powder, and the underlying sintering diffusion mechanism and activation energy have yet to be determined. In this work, we report a two-step sintering strategy to reveal the dehydrogenation effect and resultant densification mechanism during the pressureless sintering of a TiH2 powder precursor. The results show that, compared with hydrogenated-dehydrogenated (HDH) Ti powder, TiH2 powder, an intermediate of HDH-Ti powder, exhibited a higher instantaneous densification rate, greater onset relative density, rapid grain growth, and thus a smaller grain size. It also showed a grain boundary diffusion mechanism below 91% relative density and half the sintering activation energy in the intermediate sintering stage. Fundamentally, this was attributed to lattice defects generated during the dehydrogenation of TiH2 powder, which was confirmed by the greater relative density of a sintered TiH2 compact due to the two-step sintering strategy designed herein. Interestingly, the sintered sample obtained from the TiH2 powder precursor has a satisfying combination of strength and ductility that is far superior to other bulk Ti materials, especially sintered bulk Ti obtained from HDH-Ti powder. The results obtained in this paper provide theoretical guidance for using pressureless sintering to produce nearly full-density Ti and Ti alloys with good mechanical properties for structural applications.
Preparation of strong and ductile pure titanium via two-step rapid sintering of TiH2 powder
Sharma, Bhupendra,Vajpai, Sanjay Kumar,Ameyama, Kei
, p. 51 - 55 (2016)
The present work demonstrates the feasibility of preparing bulk-Ti, with high strength and good ductility, via spark plasma sintering of TiH2 powders. The microstructure and mechanical properties of bulk titanium prepared under two different pr
Pelino, Mario,Gingerich, K. A.,Gupta, S. K.
, p. 1286 - 1288 (1989)
A new, energy-efficient chemical pathway for extracting ti metal from ti minerals
Fang, Zhigang Zak,Middlemas, Scott,Guo, Jun,Fan, Peng
, p. 18248 - 18251 (2013)
Titanium is the ninth most abundant element, fourth among common metals, in the Earth's crust. Apart from some high-value applications in, e.g., the aerospace, biomedicine, and defense industries, the use of titanium in industrial or civilian applications has been extremely limited because of its high embodied energy and high cost. However, employing titanium would significantly reduce energy consumption of mechanical systems such as civilian transportation vehicles, which would have a profound impact on the sustainability of a global economy and the society of the future. The root cause of the high cost of titanium is its very strong affinity for oxygen. Conventional methods for Ti extraction involve several energy-intensive processes, including upgrading ilmenite ore to Ti-slag and then to synthetic rutile, high-temperature carbo-chlorination to produce TiCl4, and batch reduction of TiCl4 using Mg or Na (Kroll or Hunter process). This Communication describes a novel chemical pathway for extracting titanium metal from the upgraded titanium minerals (Ti-slag) with 60% less energy consumption than conventional methods. The new method involves direct reduction of Ti-slag using magnesium hydride, forming titanium hydride, which is subsequently purified by a series of chemical leaching steps. By directly reducing Ti-slag in the first step, Ti is chemically separated from impurities without using high-temperature processes.
Reactions of ground state Ti atoms with NO: Insertion versus complexation. An IR matrix isolation study
Krim, Lahouari,Prot, Christophe,Alikhani, Esm? M.,Manceron, Laurent
, p. 267 - 274 (2000)
The reaction of ground state Ti atoms with NO during condensation in solid argon has been reinvestigated. The NTiO molecule, already characterized in reactions of laser-ablated Ti, is the only product observed for the reaction between one Ti atom and one nitric oxide molecule. Isotopic data on ν1, ν2, ν3, 2ν1 and 2ν2 have been measured in the mid- and far-infrared regions. This enables a complete harmonic force-field calculation based on a bent geometry, in agreement with the conclusions of the previous study. No evidence is found, however, of a metastable nitrosyl complex intermediate, as previously proposed. This study confirms that the insertion reaction proceeds directly from the ground electronic state reagents, with no or very little activation energy. (C) 2000 Published by Elsevier Science B.V.
Effects of TiCl4 purity on the sinterability of Armstrong-processed Ti powder
Weil,Hovanski,Lavender
, p. L39-L43 (2009)
The sintering behavior of titanium powder produced via the Armstrong process from two different grades of TiCl4 was investigated by a combination of thermal, chemical, and microstructural analysis techniques. It was found that the use of lower
Electrolysis of Ti2CO solid solution prepared by TiC and TiO2
Jiao, Shuqiang,Zhu, Hongmin
, p. 243 - 246 (2007)
TiO2 can be reduced by TiC at temperatures in excess of 1000 °C, under vacuum conditions. The resulting product was found to show the structures of a Ti2CO solid solution, which has excellent conductivity like a metal. A series of experiments have been performed on the possibility of titanium electrolysis, using a Ti2CO solid solution as an anode, in a NaCl-KCl melt. Carbon monoxide (CO) was monitored at the anode during electrolysis when the potential was kept constant. The product on the cathode was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that titanium powders can be prepared through electrolysis of a Ti2CO solid solution. The oxygen content of the titanium powders was measured and the result shows that it is lower than 300 ppm.
Reduction of titanium dioxide to metallic titanium conducted under the autogenic pressure of the reactants
Eshed, Michal,Irzh, Alexander,Gedanken, Aharon
, p. 7066 - 7069 (2009)
We report on a reaction to convert titanium dioxide to titanium. The reduction reaction was done under the autogenic pressure of the reactants at 750 °C for 5 h. The MgO, a by- product, was removed by acids to obtain pure metallic titanium.
Extraction of titanium from different titania precursors by the FFC Cambridge process
Ma, Meng,Wang, Dihua,Wang, Wenguang,Hu, Xiaohong,Jin, Xianbo,Chen, George Z.
, p. 37 - 45 (2006)
Cheap titania precursors including titania dust, metatitanic acid (solid) and titanium-rich slag were tested as the feeding materials in the FFC Cambridge process (laboratory scale). Porous pellets (～20 mm in diameter, 2.0-3.0 mm in thickness) of the prec
Electrodeposition of Ti from TiCl4 in the ionic liquid 1-methyl-3-butyl-imidazolium bis (trifluoro methyl sulfone) imide at room temperature: Study on phase formation by in situ electrochemical scanning tunneling microscopy
Mukhopadhyay,Aravinda,Borissov,Freyland
, p. 1275 - 1281 (2005)
Titanium was electrodeposited from a nominal 0.24 M TiCl4 in 1-methyl-3-butyl-imidazolium bis (trifluoro methyl sulfone) imide ([BMIm]BTA) at room temperature on a Au(1 1 1) substrate. The process of electrodeposition was studied by cyclic voltammetry, chrono amperometry and in situ scanning tunneling microscopy (STM). In a first step TiCl4 is reacted to TiCl2, which is subsequently reduced to metallic Ti. Two dimensional (2D) clusters form preferentially on the terraces in the under potential deposition range. 2D clusters presumably of TiCl3 precipitates grow and coalesce to cover the whole substrate with a 2D film at a substrate potential below -1.1 V versus ferricenium/ferrocene ([Fc]+/[Fc]) redox couple. At a potential of -1.8 V a dense layer of three dimensional (3D) clusters of titanium of 1-2 nm thickness is formed. The features of the I-U tunneling spectra and the relative reduction of the effective tunneling barrier by 0.8 eV with respect to gold clearly indicate the metallic character of Ti deposits. Observation of circular holes on the Au(1 1 1) substrate after dissolution of the deposited Ti indicates the formation of Au-Ti surface alloying.
Electrochemical deposition of Pd, Ti, and Ge for applications in GaAs technology
Schuessler,Statzner,Lin,Krozer,Horn,Hartnagel
, p. L73-L75 (1996)
The electrolytic deposition of Pd, Ti, and Ge is demonstrated. A process for depositing smooth surfaces of layers from 10 to 100 nm and thicker is described. Applications of this technology for Schottky and ohmic contacts are shown and the advantages to similar evaporated metallization schemes are listed.
Ultrafine-grained titanium of high interstitial contents with a good combination of strength and ductility
Xu,Wu,Sadedin,Wellwood,Xia
, (2008)
A dehydrided Ti powder of very high oxygen content was successfully consolidated using back pressure equal channel angular processing into a fully dense bulk ultrafine-grained Ti showing apparent compressive ductility as well as high true yield and ultimate strengths of 1350 and 1780 MPa, respectively. Interstitial solid solution strengthening contributed to the majority of the increase in strength with additional contribution from ultrafine grains. Significantly, the material also exhibited much improved ductility for such a high interstitial content, thanks probably to the nonequilibrium grain boundaries and bimodal grain structure introduced during severe plastic deformation.
Combustion of TiO2-Mg and TiO2-Mg-C systems in the presence of NaCl to synthesize nanocrystalline Ti and TiC powders
Nersisyan,Lee,Won
, p. 1135 - 1146 (2003)
The combustion process of TiO2-Mg and TiO2-Mg-C systems with sodium chloride as an inert diluent was investigated. The values of combustion parameters and temperature distribution on a high-temperature wave according to the amount of sodium chloride were obtained by the thermocoupling technique. The leading stages of combustion processes are found and the sizes of reactionary zones were estimated. It is shown that the introduction of NaCl in an initial mixture promotes the formation of a nanocrystalline structure of the final products. As a result, nanosized titanium, and titanium carbide powders have been successfully obtained.
Three-dimensional nanoporous TiO2 network films with excellent electrochemical capacitance performance
Zhou, Huan,Zhong, Yuan,He, Zhishun,Zhang, Liying,Wang, Jianming,Zhang, Jianqing,Cao, Chu-Nan
, p. 1 - 7 (2014)
The three-dimensional (3D) nanoporous hydrogenated TiO2 (denoted as H-TiO2) network film on titanium substrate was fabricated by a novel and controllable method. The fabrication process involved dealloying, alkaline reflux and hydrogenation. The dealloying produced the 3D nanoporous titanium film with open pores and interconnected nanoflakes nearly perpendicular to the substrate. The oxidation of the 2D titanium nanoflakes in the alkaline reflux resulted in the formation of the TiO2 nanotubes with an inner diameter of 5-10 nm and a length larger than 1.5 μm. The 3D nanoporous TiO2 network film was formed by the self assembly of these long and thin TiO2 nanotubes. Hydrogenation induced the formation of oxygen vacancies and more hydroxyl groups on the H-TiO2 surface. The 3D nanoporous H-TiO2 network film presented a capacitance of 1.05 mF cm-2 at the scanning rate of 100 mV s- 1. Furthermore, the H-TiO2 network film electrode also showed remarkable rate capability as well as excellent electrochemical cycling stability with a capacitance reduction of less than 7% after 1000 charge-discharge cycles at the current density of 100 μA cm- 2. The prominent electrochemical capacitance properties of the 3D H-TiO2 network film electrode could be attributed to its unique structural characteristics.
Investigation of the electrochemical reduction of Na2Ti3O7 in CaCl2 molten salt
Liu, Kejia,Wang, Yaowu,Di, Yuezhong,Peng, Jianping
, p. 236 - 243 (2019/06/24)
Sodium titanate (Na2Ti3O7), as an intermediate product for producing TiO2 through alkaline process, was used as precursor to prepare Ti metal successfully by FFC Cambridge Process. For the aim to gain insight into the electro-reduction mechanism, the sintered Na2Ti3O7 pellets(～1.83 mm thinkness, open porosity ～20%) were electrolysed using them as cathodes against graphite counter electrode in the molten CaCl2. The experiments were carried out at 900 °C and the applied voltage was 3.1V. Partially reduced samples were prepared by terminating the reduction process after different electrolysis times. The obtained samples were characterised by means of X-ray diffraction analysis, SEM and EDS. The results show that Na2Ti3O7 reacts easily with molten CaCl2 as 2Na2Ti3O7 + 2CaCl2 → Ca2Ti2O6 + 4TiO2 + 4NaCl and Ca2Ti2O6 → 2CaTiO3. The electrochemical reduction of sodium titanate proceeds via sequential formation of CaTiO3, titanium sub-oxides (such as Ti4O7, Ti3O5, Ti2O3 and TiO), CaTi2O4, Ti-O solid solution and Ti. The whole reduction can be divided into three stages: the first stage is that Ca2+ ions from electrolyte are inserted into Na2Ti3O7 particles leading to the formation of titanium sub-oxides and calcium titanates(CaTiO3 and CaTi2O4); the second stage is that calcium titanates are reduced into Ti-O solid solution from outside to inside of the pellets; the third stage is that the formed Ti-O solid solution is further deoxidised to form Ti metal.
