Titanium is used in steel as an alloying element (ferro-titanium) to reduce grain size and as a deoxidizer, and in stainless steel to reduce carbon content.^[8] Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron, manganese, molybdenum, and with other metals.^[24] Applications for titanium mill products (sheet, plate, bar, wire, forgings, castings) can be found in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright-burning particles.

[edit] Pigments, Additives and Coatings

Titanium dioxide is the most commonly used compound of titanium

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.^[25] It is also used in cement, in gemstones, as an optical opacifier in paper,^[26] 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.^[3] In nature, this compound is found in the minerals anatase, brookite, and rutile.^[8] Paint made with titanium dioxide does well in severe temperatures, is somewhat self-cleaning, and stands up to marine environments.^[3] Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond.^[2]

Recently, it has been put to use in air purifiers (as a filter coating), or in film used to coat windows on buildings which when exposed to UV light (either solar or man-made) and moisture in the air produces reactive redox species like hydroxyl radicals that can purify the air or keep window surfaces clean.^[27]

[edit] Aerospace and marine

The four engines alone on the Airbus A380 use about 26 metric tons (57,000 pounds) of titanium

Due to their high tensile strength to density ratio,^[6] high corrosion resistance,^[2]and ability to withstand moderately high temperatures without creeping, titanium alloys are used in aircraft, armor plating, naval ships, spacecraft, and missiles.^[3][2] For these applications titanium alloyed with aluminium, vanadium, and other elements is used for a variety of components including critical structural parts, 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.^[10] 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 fighter and commercial aircraft. An estimated 59 metric tons (130,000 pounds) are used in the Boeing 777, 45 in the 747, 18 in the 737, 32 in the Airbus A340, 18 in the A330, and 12 in the A320. The A380 may use 146 metric tons, including about 26 tons in the engines.^[28] In engine applications, titanium is used for rotors, compressor blades, hydraulic system components, and nacelles. The titanium 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications.^[29]

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;^[2] 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, which became both the fastest and deepest diving submarines of their time.^[30]

Titanium commercial aerospace requirements (including engine components [e.g., blades, discs, rings and engine cases] and airframe components [e.g., bulkheads, tail sections, landing gear, wing supports and fasteners]) for the manufacture of:

Boeing (including both the airframes and engines)

• B787 – 295,000 pounds (133.8 tonne) of titanium
• B777 – 130,000 pounds (59 tonne) of titanium
• B747 – 100,000 pounds (45.4 tonne) of titanium
• B737 – 40,000 pounds (18.1 tonne) of titanium

Airbus (including both the airframes and engines)

• A380 – 320,000 pounds (145.1 tonne) of titanium
• A350 – 165,000 pounds (74.8 tonne) of titanium (estimated minimal requirement)
• A340 – 70,000 pounds (31.8 tonne) of titanium
• A330 – 40,000 pounds (18.1 tonne) of titanium
• A320 – 26,000 pounds (11.8 tonne) of titanium

Source: TIMET 2007 Form 10-K (converted from metric tons to pounds)