Titanium metal connects well with bone, so it has found surgical applications such as in joint replacements (especially hip joints) and tooth implants.
The largest use of titanium is in the form of titanium(IV) oxide. It is extensively used as a pigment in house paint, artists' paint, plastics, enamels and paper. It is a bright white pigment with excellent covering power. It is also a good reflector of infrared radiation and so is used in solar observatories where heat causes poor visibility.
Titanium(IV) oxide is used in sunscreens because it prevents UV light from reaching the skin. Nanoparticles of titanium(IV) oxide appear invisible when applied to the skin.
Furthermore, Zirconium does not absorb neutrons, making it an ideal material for use in nuclear power stations. More than 90% of zirconium is used in this way. Nuclear reactors can have more than 100,000 metres of zirconium alloy tubing. With niobium, zirconium is superconductive at low temperatures and is used to make superconducting magnets.
Zirconium metal is protected by a thin oxide layer making it exceptionally resistant to corrosion by acids, alkalis and seawater. For this reason it is extensively used by the chemical industry.
Zirconium(IV) oxide is used in ultra-strong ceramics. It is used to make crucibles that will withstand heat-shock, furnace linings, foundry bricks, abrasives and by the glass and ceramics industries. It is so strong that even scissors and knives can be made from it. It is also used in cosmetics, antiperspirants, food packaging and to make microwave filters.