TITANIUM (Ti, atomic number 22) Titanium is a lustrous grey metallic element used principally to make lightweight, resistant alloys. It is one of the transitional elements of the periodic table and has many desirable properties, most notably its incredible strength and durability.
Titanium is abundant in the Earth and has been detected in meteorites, in our sun and other stars, titanium oxide bands being particularly prominent in the spectra of M type stars. Titanium is also found on our moon, rocks obtained during the Apollo 17 mission showed presence of titanium oxide (TiO2).
Titanium is immune to corrosive attacks by saltwater and marine atmosphere and exhibits exceptional resistance to a broad range of corrosive gases, acids and alkalis. Titanium is immune to microbiologically influenced corrosion and is physiologically inert and hypoallergenic. Titanium is virtually non-magnetic, making it ideal for applications where electromagnetic interference must be minimized. Pure titanium is about as strong as steel yet nearly 50% lighter. When added to various alloys, its hardness, toughness and tensile strength can be increased dramatically.
Titanium is never found uncombined and occurs as an oxide in ilmenite, rutile and sphene, and is present in titanates and in many iron ores. Titanium is present in the ash of coal, in plants, and in the human body. Titanium is ductile only when it is free of oxygen and nitrogen (air), melting at 1660C (3020F) and boiling at 3287C (5949F). The complex process of converting titanium ore into metal has only been commercially viable for a little more than 50 years. The use of titanium has since then expanded by an average of 8% per year.
Titanium was first discovered in 1791 in Menachan Valley, Cornwall, England, by clergyman and amateur chemist William Gregor. Gregor analyzed gun powder-like sand and found a reddish brown calx he could not identify. Four years later in Berlin, renowned chemist Martin Heinrich Klaproth independently discovered the element in rutile. Klaproth named the element Titanium, after the mythological Titans, first sons of the earth.
But isolating titanium would remain elusive for almost a century. Many failed attemps were made by scientists such as Vauquelin, Heinrich Rose, Bezelius and Klaproth himself, and it was not until 1887 that titanium was first isolated (95% pure) by Lars Nilson and Otto Pettersson. Henri Moissan then used his electric furnace to produce 98% purity. Titanium was finally isolated at 99.9% purity in 1910 by Matthew Albert Hunter at Rensselaer Polytechnic Institute in cooperation with the General Electric Company. The metal remained a laboratory curiosity until 1946, when William Justin Kroll of Luxembourg showed that titanium could be produced commercially by reducing titanium tetrachloride (TiCl4) with magnesium. This method is widely used for titanium metal production today and Kroll is recognized as the father of this modern industry.
After the Second World War, Air Force studies concluded that titanium-based alloys were of potentially great importance. The emerging need for higher strength/weight ratios in jet aircraft structures and engines could not be satisfied efficiently by either steel or aluminum. The Department of Defense therefore provided production incentives to boost-start the titanium industry. After the impetus was provided by the aerospace industry, the ready availability of the metal gave rise to opportunities for new applications in other markets, such as chemical processing, medicine, power generation and more.
Titanium's outstanding strength-to-lightweight ratio and its incredible resistance to most forms of corrosion have been the primary historical incentives for utilizing titanium in industry, replacing stainless steels, copper alloys and other metals.
Titanium's many desirable properties have made it the metal of choice in many industries. No other engineering metal has risen so swiftly to pre-eminence in critical and demanding applications. Titanium and its alloys have proven to be technically superior in a wide variety of industrial and commercial applications in such fields as aerospace, architecture, sporting equipment, military hardware, watch making, eyewear, medical implants, dental products and more.
The physiological inertness of titanium makes it available as a replacement for bones and cartilage in a variety of surgeries. Titanium is used for heart valves, pace makers, dental implants, artificial hips and joints. Titanium is also used in surgery equipment and wheelchairs. Titanium is used in metallic alloys as a substitute for aluminum because of its strength and lightweight, along with its heat and corrosion resistance. Alloyed with aluminum and vanadium (aircraft grade titanium 6.4), titanium is used in aircraft for firewalls, outer skin, landing-gear components, hydraulic tubing, and engine supports. The compressor blades, disks, and housing of jet engines are also made of titanium. A commercial jet transport uses between 3500 and 12000 kg (7000 and 25000 pounds) of the metal. A supersonic transport uses much more, between 14 to 45 metric tons of titanium. The use of titanium has made space exploration possible. The Mercury, Gemini, and Apollo capsules were made largely of the metal. The space shuttle has many titanium parts as well as the international space station. Titanium is also widely used in military hardware such as jet fighters, missiles, tanks, ships and submarines.
Titanium dioxide (TiO2) is extensively used for both house and artist's paint because it is permanent and has a good covering power. Titanium paint is an excellent reflector of infrared, and is widely used in solar observatories where heat causes poor visibility. Titanium dioxide is also common in the production of pigments for paper, plastics, rubber, cosmetics, textiles, glass and ceramics. Titanium is used in heat exchangers and in desalinization plants because of its outstanding ability to withstand saltwater and atmospheric corrosion (regardless of pollutants). This also explains why it provides total reliability in many marine or naval applications. In metallurgy, titanium alloys are employed as deoxidizers and denitrogenizers to remove oxygen and nitrogen from molten metals.
The main alloy used by Titanium Era is Titanium 6.4 (6Al/4V). It is composed of 90% titanium, 6% aluminum and 4% vanadium. Titanium 6.4 was developed in the 1950's and is known as aircraft grade titanium. Aircraft grade titanium has a tensile strength of up to 150,000 psi (pounds per square inch) and a Brinell hardness value of 330.
For even stronger jewelry, extra hard Titanium 6.6.2 is used (6Al/6V/2Sn). It is composed of 86% titanium, 6% aluminum, 6% vanadium, 2% tin. This is practically the strongest titanium alloy on the market and is mainly used in the aerospace industry for its great strength and lightweight. Titanium 6.6.2 has a tensile strength of up to 180,000 psi and a Brinell hardness value of 389.