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PROPERTIES
Interesting facts about titanium that explain which it is the metal of choice for many uses, in sports, medicine, and jewelry.

The Name
The name "Titanium" was derived from the Titans of Greek mythology, symbolizing strength.

Resistance To Corrosion
Titanium is nearly as resistant to corrosion as platinum, and resists many acids, salt solutions, and even chlorine gas. Like many metals, it is not water soluble, save perhaps in concentrated acids. It is most useful for the way it combines high-strength a light-weigth. Titanium may be 60% heavier than aluminium, but it is 100% stronger. It is 45% lighter than steel, but equally strong. Thus, it is an ideal replacement for applications where a strong metal is required, light weight an advantage, and where metal fatigue an issue.

It is a passive oxide coating that leads to corrosion resistance, and resistance to tarnishing at room temperature.

Density and Strength
Titanium is a very light metal. It weighs only 4.5g/cm3, which makes it 4.5 times more dense than water. To compare, lead is much denser at 11.3 times more dense than water, and aluminium is lighter at 2.7 times the density of water. Titanium has the highest strength to density ratio it is the material of choice only for certain niche application areas because of its high price.

Density and tensile strenght
SubstanceGrams per
cubic cm
Tensile strenght
in MPa
Water1.0liquid
Aluminium2.740-50, 310 in alloy
Titanium4.5240-434
Zinc7.1110200
Nickel8.9140195
Copper8.9210
Lead11.312
Mercury13.6liquid
Gold19.3100

Characteristics of titanium and structural metals
Ti Fe Ni Al
Melting Temperature (C) 1670 1538 1455 660
Allotropic Transformation (C) β882 α γ912α - -
Crystal Structure bcc → hex fcc → bcc fcc fcc
Room Temperature E (GPa) 115 215 200 72
Yield Stress Level (MPa) 1000 1000 1000 500
Density (g/cm3) 4.5 7.9 8.9 2.7
Comparative Corrosion Resistance Very High Low Medium High
Comparative Reactivity with Oxygen Very High Low Low High
Comparative Price of Metal Very High Low High Medium


Physico-Chemical Properties
Titanium will burn to form titanium dioxide when heated at 610C in the presence of oxygen. Titanium can also burn in pure nitrogen gas at 800C with titanium nitride resulting from the chemical reaction. Titanium is only weakly attracted to magnets. It does not conduct electricity very well, or heat. This low thermal conductivity is why, unlike other metals, titanium does not feel cold upon its initial contact with the skin. At high temperatures, titanium reacts readily with oxygen and carbon, creating special challenges in the preparation of titanium metal, crystals, or powder.

Some commercial titanium alloys
Common NameAlloy Composition (wt%) T β (C)
α Alloys and CP Titanium
Grade 1 e CP-Ti (0.2Fe, 0.18O) e890
Grade 2 eCP-Ti (0.3Fe, 0.25O) e 915
Grade 3 e CP-Ti (0.3Fe, 0.35O) e920
Grade 4 eCP-Ti (0.5Fe, 0.40O) e 950
Grade 7 eTi-0.2Pd e 915
Grade 12 eTi-0.3Mo-0.8Ni e880
Ti-5-2.5 e Ti-5Al-2.5Sn e1040
Ti-3-2.5 e Ti-3Al-2.5V e 935
α + β Alloys
Ti-811 Ti-8Al-1V-1Mo 1040
IMI 685 Ti-6Al-5Zr-0.5Mo-0.25Si 1020
IMI 834 Ti-5.8Al-4Sn-3.5Zr-0.5Mo-0.7Nb-0.35Si-0.06C 1045
Ti-6242 Ti-6Al-2Sn-4Zr-2Mo-0.1Si 995
Ti-6-4 Ti-6Al-4V (0.20O) 995
Ti-6-4 ELI Ti-6Al-4V (0.13O) 975
Ti-662 Ti-6Al-6V-2Sn 945
IMI 550 Ti-4Al-2Sn-4Mo-0.5Si 975
β Alloys
Ti-6246 Ti-6Al-2Sn-4Zr-6Mo 940
Ti-17 Ti-5Al-2Sn-2Zr-4Mo-4Cr 890
SP-700 Ti-4.5Al-3V-2Mo-2Fe 900
Beta-CEZ Ti-5Al-2Sn-2Cr-4Mo-4Zr-1Fe 890
Ti-10-2-3 Ti-10V-2Fe-3Al 800
Beta 21S Ti-15Mo-2.7Nb-3Al-0.2Si 810
Ti-LCB Ti-4.5Fe-6.8Mo-1.5Al 810
Ti-15-3 Ti-15V-3Cr-3Al-3Sn 760
Beta C Ti-3Al-8V-6Cr-4Mo-4Zr 730
B120VCA Ti-13V-11Cr-3Al 700


α Titanium 8.4 20 523 0.42
Ti-6Al-4V 9.0 7 530 1.67
Ti-15-3 8.5 8 500 1.4
Fe 11.8 80 450 0.09
Ni 13.4 90 440 0.07
Al 23.1 237 900 0.03


Coloration
A rich, putty-grey color allows it to distinguish itself from the more common silver and gold used in jewelry. The metal is commonly polished in a variety of ways to produce matte or shiny surface finishes, or anodized to create all colors of the rainbow.

Radioactive Potential
Bombardment with deuterons can render titanium very radioactive. It will emit positions and hard gamma rays.

Titanium Dioxide
Most of the inudstrial application of titanium is in the form of titanium dioxide (TiO2), used as a dense, fade-resistant pigment in paints, paper, plastics, toothpaste. Titanium dioxide has excellent covering power. An interesting note is that the pigment is used by astronomers because of its ability to reflect infrared radiation. It is also especially useful in hot climates to keep interiors cooler when used in exterior paint. When used in paper or cement, the compound also imparts greater strength to the material.

Applications
Titanium's special combination of light weight, strenght, resistance to heat and corrosion make it especially useful in military applications such as aircrafts, armor plating, naval ships, spacecraft and missiles. In civilian applications is valuable in aviation, racket sports, bicycle frames, golf clubs, eyewear frames, light laptop computers, medical implants and jewelry. It is the material of choice for the 10-12% of individuals that suffer dermatitis owing to nickel sensitivity. Titanium is a non-toxic, inert biomaterial and it is ideal for dental and other implants.

Alloys
Addition of titanium to alloys will have different effects depending on the other metals involved. For instance, with steel, titanium will deoxidize and reduce grain size. In stainless steel it is useful to reduce carbon content. With aluminium, grain size is reduced; titanium will harden both copper and vanadium.

In particular, titanium vanadium alloys are widely used in aviation in the making of landing gear, hydraulic tubing, fire walls, etc.

Crystal Structure
Pure titanium exhibits an allotropic phase transformation at 882C, changing from a body-centered cubic crystal structure (β phase) at higher temperatures to a hexagonal close-packed crystal structure (α phase) at lower temperatures. crystal structure alpha phase titanium Unit cell of α phase

crystal structure beta phase titanium Unit cell of β phase

The exact transformation temperature is strongly influenced by interstitial and substitutional elements and therefore depends on the purity of the metal.

The crystal packing of titanium helps predict how titanium will give in to stretching or other deforming forces, as deformations will tend to occur along crystal planes that align and dictate the direction of the weakest planes in the material.

Extraction
Though it is the ninth most abundant element in the Earth's crust, titanium metal is always found bound to other elements. It is most commonly associated with igneous rocks and their derived sediments. It is found in rutile, anatase, ilmenite, brookite, perovskite, titanite , as well in many iron ores. Ilmenite and rutile are difficult to find in high concentrations, but they are the only commercially viable source of titanium ore at this time. Ilmenite is mined in Australia, Brazil, Russia, Canada, Sri Lanka, Norway, China, South Africa, Thailand, India, Malaysia, Sierra Leone and the United States.

Titanium is not easily extracted from the ore. As recently as 1946, William Justin Kroll discovered means to extract it commercially by reducing titanium tetrachloride with magnesium. The oxide is converted to chloride through carbochlorination, whereby chlorine gas is passed over red-hot rutile or ilmenite in the presence of carbon to make TiCl4. This is condensed and purified by fractional distillation and then reduced with 800 C molten magnesium in an argon atmosphere. Though complex and expensice, the Kroll process is still used today.

The FFC Cambridge Process is a newer method that is being increasingly favored. Because it reduces the cost of extraction, it is hoped that titanium will be used more extensively in the aerospace industry, for example.

Titanium oxide is produced commercially mixing ground mineral ore and mixing it with potassium carbonate and aqueous hydrofluoric acid. This chemical reaction product potassium fluorotitanate (K2TiF6) is extracted with hot water and decomposed with ammonia, producing a ammoniacal hydrated oxide. This in turn is ignited in a platinum vessel, which creates pure titanium dioxide.