Zirconium is a silver-grey transition metal, a type of element that is malleable and ductile and easily forms stable compounds. It is also highly resistant to corrosion. Zirconium and its alloys have been used for centuries. Rocks containing zircon that were found in Australia in 2000 were dated to be 4.4 billion years old.
Zirconium alloys can be found in pipes, fittings and heat exchangers. Zirconium is also used in steel alloys, coloured glazes, bricks, ceramics, abrasives, flashbulbs, lamp filaments, artificial gemstones and some deodorants. Other uses for zirconium include catalytic converters, furnace bricks, lab crucibles, surgical instruments, television glass, removing residual gases from vacuum tubes, and as a hardening agent in alloys such as steel. Also, zirconium carbonate is used to treat poison ivy. Zirconium combines with silicate to create the natural semiprecious gemstone zircon, which is commonly used as a substitute for diamonds.
Zirconium has very low toxicity and it is estimated that humans ingest about 50 micrograms per day, most of which passes through the digestive system without being absorbed. The use of lithium zirconate may be useful in absorbing excess carbon dioxide in the atmosphere.
Zirconium powder can spontaneously ignite in air, Because of this property, powdered zirconium is sometimes used in explosive devices. However, zirconium powder can cause eye irritation for short-term exposure and can be harmful to the lungs for long-term or repeated exposure.
Because if its high tolerance to corrosion and its strength, zirconium is present in several compounds in various medical uses. Zirconia prosthetics were developed as an alternative to titanium, steel and aluminium and have proven to be both more resilient and show better biocompatibility.
Zirconia is also widely used in dental restorations, and is typically stabilized with yttria. The yttria-zirconia compound has many benefits over other materials. It is more compatible with the human body and has twice the flexural strength and four times the compression resistance of steel. It also has greater resistance to acids bases found in many foods.