Thorium dioxide

Thorium dioxide, ThO₂ (thoria, formely called thorina) is a white, crystalline powder.

The compound is radioactive due to the radioactivity of Thorium. Thorium dioxide can be used as a nuclear fuel.(Refer to the article of Thorium for more information on this application.) The high thermal stability of thorium dioxide has given it applications in flame spraying and high temperature ceramics. Thorium dioxide was the primary ingredient in the X-ray contrast medium Thorotrast. Use of Thorotrast was abandoned when it turned out to be a carcinogen.

Thorium dioxide is used as a stabilizer in tungsten electrodes in tig welding and electron tubes. As an alloy, thoriated tungsten metal is not easily deformed because the high fusion material thoria augments the high temperature mechanical properties, and thorium helps stimulate the emmission of electrons (thermions). It is the most popular oxide additive because of its low cost, but is being phased out in favor of non-radioactive elements such as cerium, lanthanum and zirconium.

This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia article. Browse Wikipedia for more information.