Yittrium


Reference has been made already to the existence of a set of inner transition elements, following lanthanum, in which the quantum level being filled is neither the outer quantum level nor the penultimate level, but the next inner. These elements, together with yttrium (a transition metal), were called the rare earths , since they occurred in uncommon mixtures of what were believed to be earths or oxides. With the recognition of their special structure, the elements from lanthanum to lutetium were re-named the lanthanons or lanthanides. They resemble one another very closely, so much so that their separation presented a major problem, since all their compounds are very much alike. They exhibit oxidation state -i-3 and show in this state predominantly ionic characteristics—the ions.  [c.441]

Scandium is a silver-white metal which develops a slightly yellowish or pinkish cast upon exposure to air. A relatively soft element, scandium resembles yttrium and the rare-earth metals more than it resembles aluminum or titanium.  [c.50]

Yttrium occurs in nearly all of the rare-earth minerals. Analysis of lunar rock samples obtained during the Apollo missions show a relatively high yttrium content.  [c.73]

Yttrium oxide also is used to produce yttrium-iron-garnets, which are very effective microwave filters.  [c.74]

Small amounts of yttrium (0.1 to 0.2%) can be used to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys.  [c.74]

Yttrium is also finding application in laser systems and as a catalyst for ethylene polymerization.  [c.74]

Natural yttrium contains but one isotope, 89Y. Nineteen other unstable isotopes have been characterized.  [c.74]

Yttrium metal of 99.9% purity is commercially available at a cost of about 75/oz.  [c.74]

Gadolinium yttrium garnets are used in microwave applications and gadolinium compounds are used as phosphors in color television sets.  [c.188]

III) nitrate 4-water (III) oxide (III) sulfate 8-water Yttrium chloride fluoride  [c.270]

Group III with electronic configuration 5s 4d . The principal ore is gadolinite (a silicate also containing lanthanides). Y2O3 containing Eu is used as a red phosphor in colour television. Yttrium iron garnets are used as microwave filters.  [c.431]

The only on-line detector for TEM with moderate-to-high spatial resolution is the slow-scan CCD camera. A light-sensitive CCD chip is coupled to a scintillator screen consisting of plastic, an yttrium-aluminium garnet (Y AG) crystal, or phosphor powder. This scintillator layer deteriorates the original resolution of the CCD chip elements by scattermg light into neighbouring pixels. Typical sizes of chips at present are 1024 x 1024 or 2048 X 2048 pixels of (19-24 uu) the achievable dynamic range is about 10 grey levels.  [c.1632]

This also illustrates the use of different wavelengths of light to obtain much more infomration on the nature of the film. Here A and T are plotted versus the wavelength of light ( ) and the line drawn tln-ough these data represents a fit calculated for the various fihns of yttrium oxide deposited on silica as shown at tire bottom of the figure [40],  [c.1888]

Ytterby, a village in Sweden near Vauxholm) Yttria, which is an earth containing yttrium, was discovered by Gadolin in 1794. Ytterby is the site of a quarry which yielded many unusual minerals containing rare earths and other elements. This small town, near Stockholm, bears the honor of giving names to erbium, terbium, and ytterbium as well as yttrium.  [c.73]

Yttrium has a silver-metallic luster and is relatively stable in air. Turnings of the metal, however, ignite in air if their temperature exceeds 400oC. Finely divided yttrium is very unstable in air.  [c.73]

Yttrium oxide is one of the most important compounds of yttrium and accounts for the largest use. It is widely used in making YVOr europium, and Y2O3 europium phosphors to give the red color in color television tubes. Many hundreds of thousands of pounds are now used in this application.  [c.74]

Yttrium iron, aluminum, and gadolinium garnets, with formulas such as Y3FesOi2 and Y3AI5O12, have interesting magnetic properties. Yttrium iron garnet is also exceptionally efficient as both a transmitter and transducer of acoustic energy. Yttrium aluminum garnet, with a hardness of 8.5, is also finding use as a gemstone (simulated diamond).  [c.74]

Alloys with other useful properties can be obtained by using yttrium as an additive. The metal can be used as a deoxidizer for vanadium and other nonferrous metals. The metal has a low cross section for nuclear capture. 90Y, one of the isotopes of yttrium, exists in equilibrium with its parent 90Sr, a product of nuclear explosions. Yttrium has been considered for use as a nodulizer for producing nodular cast iron, in which the graphite forms compact nodules instead of the usual flakes. Such iron has increased ductility.  [c.74]

Europium oxide is now widely used as a phospor activator and europium-activated yttrium vanadate is in commercial use as the red phosphor in color TV tubes. Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years.  [c.178]


See pages that mention the term Yittrium : [c.46]    [c.431]    [c.431]    [c.431]    [c.2422]    [c.73]    [c.73]    [c.74]    [c.198]    [c.217]    [c.158]    [c.280]    [c.300]    [c.309]    [c.327]    [c.339]    [c.359]    [c.382]    [c.653]    [c.673]    [c.722]    [c.843]    [c.849]    [c.910]    [c.911]    [c.912]    [c.913]    [c.914]    [c.964]    [c.1186]   
Gas turbine engineering handbook (2002) -- [ c.433 ]