Titanium is the ninth most abundant metal in Earth’s crust. It is a hard, lustrous, silvery metal, that is found in igneous and metamorphic rock formations and their derived alluvial deposits. Titanium forms a protective oxide coating making it highly resistant to corrosion. This process not only happens in air but also under water. Having a low modulus of elasticity means that titanium is not also very flexible, but returns to its original shape after bending, resulting in its importance to shape memory alloys. Titanium and its alloys are also characterised by their lightness: despite being as strong as steel, titanium is about 40% lighter in weight. This is what makes Titanium the material of choice in aerospace applications. It is also non-magnetic and biocompatible (non-toxic, non-allergenic), leading to increased use in the medical field, for hip replacements for example.
Titanium dioxide, TiO2 is used as a white pigment in paints, cosmetics and plastics as it provides great opacity and brightness. The same material is also used in the manufacture of heat resisting and self-cleaning glass. Titanium dioxide is highly efficient at photo catalysing dirt in sunlight and reaching the super hydrophilic state. It is also non-toxic, and relatively easy to handle and deposit into thin films.
Titanium can be used as a raw material in 3D printing. In 2013, researchers at Australia’s Commonwealth Scientific and Industrial Research Organization 3D-printed a pair of lightweight titanium horseshoes for racehorses.