Titanium is a chemical element with atomic number 22 and symbol Ti that exists as a lustrous transition metal with exceptional strength-to-weight properties.
Physical Properties
Structural Characteristics
Titanium appears as a silvery grey-white metal with a density of 4.502 g/cm³ at 20°C. The metal exhibits remarkable strength comparable to steel while maintaining just 60% of steel’s density. It melts at 1668°C and boils at 3287°C.
Mechanical Properties
The pure metal shows an ultimate tensile strength of 434 MPa, matching low-grade steel alloys. When alloyed with other elements, titanium can achieve strengths over 1,400 MPa. The metal retains its strength up to 430°C but weakens at higher temperatures.
Chemical Behavior
Reactivity Patterns
Titanium forms a protective oxide layer instantly upon exposure to air. This passive film grows to 25 nm thick over four years, providing excellent corrosion resistance. The metal resists corrosion from seawater and most acids but dissolves in hot concentrated acids.
Oxidation States
The element primarily exists in the +4 oxidation state, though +3 compounds are common. It readily combines with oxygen at high temperatures and uniquely burns in pure nitrogen at 800°C.
Industrial Applications
Aerospace Usage
About two-thirds of titanium production goes into aircraft engines and frames. The Boeing 787 uses 116 metric tons of titanium products, while the Airbus A380 requires 77 tons.
Medical Implementations
Titanium serves in medical implants due to its biocompatibility. Hip replacements and dental implants made from titanium can function for over 20 years. The metal’s non-magnetic nature allows MRI scanning of patients with implants.
Environmental Presence
Natural Occurrence
As Earth’s ninth most abundant element, titanium comprises 0.63% of the crust. It appears primarily in minerals like rutile and ilmenite. China leads global production, contributing 33.1% of world output.
Biological Role
Plants contain varying amounts of titanium, from 1 ppm in most species to 80 ppm in horsetail and nettle. The metal may influence carbohydrate production in plants through unknown mechanisms.
