Yttrium oxides are a component of the phosphors used to produce the red color in television picture tubes. The oxides have potential use in ceramics and glass. Yttrium oxides have high melting points and impart shock resistance and low expansion to glass. Yttrium iron garnets are used to filter microwaves and as transmitters and transducers of acoustic energy. Yttrium aluminum garnets, with a hardness of 8.5, are used to simulate diamond gemstones. Small quantities of yttrium may be added to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys. Yttrium is used as a deoxidizer for vanadium and other nonferrous metals. It is used as a catalyst in the polymerization of ethylene.
Yttrium (Y, atomic number 39) was first isolated in 1828 by Friedrich Wöhler. Named for Ytterby, a village in Sweden near Vauxholm. Ytterby is the site of a quarry which yielded many minerals containing rare earths and other elements (erbium, terbium, and ytterbium). Yttrium has a metallic silver luster. It is relatively stable in air except when finely divided. Yttrium turnings will ignite in air if their temperature exceeds 400°C.