Uses of yttrium
Before the era of flat-screen televisions, TV sets contained large cathode ray tubes, which were large glass tubes that projected images on the screen. Yttrium oxide, doped with the element europium, provided the red color on millions of color-television sets.
Yttrium oxide (yttria) is added to zirconium oxide (zirconia) to make an alloy that stabilizes the crystal structure of zirconia, which ordinarily changes with temperature. "Essentially, yttria locks in the cubic structure of zirconia, creating a ceramic with exceptionally high toughness that is suitable for use at very high temperatures," Gambogi said. "This type of ceramic is used in a variety of applications from electronics to thermal barrier coatings on jet engines to medical implants."
Synthetic garnets made with an yttrium-aluminum composite were commonly sold in the 1970s as simulated diamonds and other gemstones, but they eventually gave way to the cubic zirconia, Gambogi said. These days, yttrium aluminum garnets (YAG) are used as the crystals that amplify light in industrial lasers. Yttrium iron garnets are used for microwave filters, as well as in radar and communication technology.
"Although yttrium is found in a multitude of applications, the largest end uses are ceramics and phosphors," Gambogi told Live Science. "Lesser amounts are used in metallurgy, glass polishing and additives, and catalysts. There also are a multitude of electronic applications, but oxygen sensors are an especially important use."
Yttrium is widely used to produce phosphors that are used in cell phones and larger display screens as well as general lighting. Yttrium in red phosphors in color television tubes led to widespread use in the 1960s and '70s. Fluorescent tubes (linear and compact) use significantly more yttrium per watt than LED bulbs.
The radioactive isotope yttrium-90 is used in radiation therapy to treat liver cancer and some other cancers.