| 摘要 |
<p>1,163,503. Luminescent materials. RADIO CORPORATION OF AMERICA. 15 Feb., 1968 [1 March, 1967], No. 7557/68. Heading C4S. A method of preparing a luminescent Eu activated oxysulphide of Y, Gd, La and/or Lu comprises heating to 700‹ to 1250‹ C. a mixture containing a composition which yields alkali metal sulphides and polysulphides when so heated, an oxide of Y, Gd, La and/or Lu and a Eu compound, the molar ratio of Eu to Y + Gd + La + Lu being 0À001 to 0À1. The mixture may include alkali metal sulphates, phosphates, arsenates and germanates. (La, Eu) 2 O 2 S is prepared by heating in N 2 a dry mixture of La 2 O 2 and Eu 2 O 3 , obtained from a ball milled acetone slurry, with Na 2 S 2 O 3 or Na 2 CO 3 , K 2 CO 3 and sulphur, the oxides reacting with molten sulphide to form a phosphor used in colour TV tubes. Li may replace Na or K and hydroxides, sulphates or thiosulphates may replace the carbonates.</p> |
