October 31 - November 3, 2004
Element of the Day
Thursday, October 21
Titanium
is present in meteorites and the sun. Rocks obtained during the Apollo 17 lunar
mission showed presence of 12.1% TiO2; rocks obtained during earlier Apollo
missions show lower percentages. The metal was a laboratory curiosity until
Kroll, in 1946, showed that titanium could be produced commercially by reducing
titanium tetrachloride with magnesium.
Discovered by: Discovered by Gregor in 1791, named by Klaproth in 1795.
Uses: 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. Titanium is as strong as steel, but 45%
lighter. It is 60% heavier than aluminum, but twice as strong.
Titanium has potential use in desalination plants for converting seawater into
fresh water. The metal has excellent resistance to seawater and is used for
propeller shafts, rigging, and other parts of ships exposed to salt water. A
titanium anode coated with platinum has been used to provide cathodic protection
from corrosion by salt water.
It is produced artificially for use as a gemstone, but it is relatively soft. Star sapphires and rubies exhibit their asterism as a result of the presence of TiO2. Titanium:Sapphire crystals are used as a lasing medium in solid-state lasers.
Titanium dioxide is extensively used for both house paint and artist's paint, because it is permanent and has good covering power. Titanium oxide pigment accounts for the largest use of the element. Titanium paint is an excellent reflector of infrared, and is extensively used in solar observatories where heat causes poor viewing conditions.