Aircraft titanium

Titanium is not a rare element it is the most abundant transition metal after iron, and is widely distributed in the earth s surface, mainly as the dioxide TiOj and ilmenite FeTi03. It has become of commercial importance since World War II mainly because of its high strength-weight ratio (use in aircraft, especially supersonic), its... 

Titanium is important as an alloying agent with aluminum, molybdenum, manganese, iron, and other metals. Alloys of titanium are principally used for aircraft and missiles where lightweight strength and ability to withstand extremes of temperature are important. 

Flame-Retardant Treatments For Wool. Although wool is regarded as a naturally flame-resistant fiber, for certain appHcations, such as use in aircraft, it is necessary to meet more stringent requirements. The Zirpro process, developed for this purpose (122,123), is based on the exhaustion of negatively charged zirconium and titanium complexes on wool fiber under acidic conditions. Specific agents used for this purpose are potassium hexafluoro zirconate [16923-95-8] [16923-95-8] K ZrF, and potassium hexafluoro titanate [16919-27-0], K TiF. Various modifications of this process have been... 

If the ECM of titanium is attempted in sodium chloride electrolyte, very low (10—20%) current efficiency is usually obtained. When this solution is replaced by some mixture of fluoride-based electrolytes, to achieve greater efficiencies (> 60%), a higher voltage (ca 60 V) is used. These conditions ate needed to break down the tenacious oxide film that forms on the surface of titanium. It is this film which accounts for the corrosion resistance of titanium, and together with its toughness and lightness, make this metal so useful in the aircraft engine industry. 

Niobium is important as an alloy addition in steels (see Steel). This use consumes over 90% of the niobium produced. Niobium is also vital as an alloying element in superalloys for aircraft turbine engines. Other uses, mainly in aerospace appHcations, take advantage of its heat resistance when alloyed singly or with groups of elements such as titanium, tirconium, hafnium, or tungsten. Niobium alloyed with titanium or with tin is also important in the superconductor industry (see High temperature alloys Refractories). 

Cu—(Ti, Zr)—Ni eutectic clad strip, RS foil titanium/zirconium-ba titanium tubiag, aircraft... 

Titanium is the ninth most abundant element ia the earth s cmst, at approximately 0.62%, and the fourth most abundant stmctural element. Its elemental abundance is about five times less than iron and 100 times greater than copper, yet for stmctural appHcations titanium s aimual use is ca 200 times less than copper and 2000 times less than iron. Metal production began in 1948 its principal use was in military aircraft. Gradually the appHcations spread to commercial aircraft, the chemical industry, and, more recently, consumer goods. 

The alloys of titanium utilised in industrial applications have compositional specifications tabulated by ASTM. The ASTM specification number is given in Table 14 for the commercially important alloys. MiUtary specifications are found under MIL-T-9046 and MIL-T-9047, and aerospace material specifications for bar, sheet, tubing, and wine under specification numbers 4900—4980. Every large aircraft company has its own set of alloy specifications. 

No fewer than 14 pure metals have densities se4.5 Mg (see Table 10.1). Of these, titanium, aluminium and magnesium are in common use as structural materials. Beryllium is difficult to work and is toxic, but it is used in moderate quantities for heat shields and structural members in rockets. Lithium is used as an alloying element in aluminium to lower its density and save weight on airframes. Yttrium has an excellent set of properties and, although scarce, may eventually find applications in the nuclear-powered aircraft project. But the majority are unsuitable for structural use because they are chemically reactive or have low melting points." ... 

In primer formulations for adhesive bonding of metals, the coupling agents that are most frequently used are those based on epoxy and amine functionalities. Aqueous solutions of aminosilanes have been successfully used for obtaining stable adhesive bonds between epoxy and steel [10] and epoxy and titanium [11,12], while epoxy functional silanes are preferable for applications involving aluminum substrates [13,14], A simple solution of % epoxy functional silane in water is currently used for field repairs of military aircraft [15] where phosphoric acid anodization would be extremely difficult to carry out, and performance is deemed quite acceptable. 

Mechanical properties of various titanium alloys are given in Table 5.16. In general the corrosion behaviour of those titanium alloys developed for the aircraft industry is very similar to that of unalloyed titanium . The addition of some alloying elements may increase resistance to one medium, but decrease it to others . 

Titanium finds uses as diverse as aircraft turbine blades, lightweight bicycle frames, and Ti02 smoke for skywriting. 

Society, of course, is in need of metals such as titanium to produce jet engines for aircraft, as much as it needs petroleum products as a source of fuel for their running. Like oil, mineral deposits do not regenerate themselves when they are exhausted. While there exists no threat from any immediate scarcity of mineral sources, if these are to be recovered with minimum or practically no impact on the environment, then it is required that society pays more for these products in order to meet the additional costs incurred when implementing an environmentally benign mining operation. 

---