Claims
- 1. A BaFBr:Eu phosphor compound produced by a process which comprises:
- (a) preparing a slurry containing BaF.sub.2, BaBr.sub.2 and a europium halide, wherein the amount of BaBr.sub.2 present is at least 1.4 times that required stoichiometrically to form BaFBr;
- (b) agitating said slurry for a time sufficient to permit substantially all of said BaF.sub.2 to react with said BaBr.sub.2 to form BaFBr;
- (c) spray drying the resulting slurry of step (b) under conditions that produce porous spheroidal agglomerates having an average diameter larger than that of the preselected diameter;
- (d) firing said spheroidal agglomerates in an inert atmosphere for from about 10 to about 120 minutes at a temperature of from about 650.degree. C. to about 800.degree. C.;
- (e) cooling the fired material of step (d) to ambient temperature in an inert atmosphere;
- (f) washing the cooled material of step (e) with methanol or a 90:10 by volume mixture of water and citric acid to selectively remove excess BaBr.sub.2 ; and
- (g) drying the washed material of step (f) to produce a free flowing powder of the Ba.sub.1-y Eu.sub.y FBr phosphor compound where y is a number from 0.001 to 0.2 and having high speeds and afterglow (lag) value of 1.29 or less in response to x-ray radiation.
Parent Case Info
This is a division of application Ser. No. 07,814,266, filed Dec. 24, 1991, now U.S. Pat. No. 5,279,765.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
254836 |
Feb 1988 |
EPX |
Non-Patent Literature Citations (1)
Entry |
Stevels et al., Phillips Research Report, vol. 30(5), pp. 277-290 (1975) No month. |
Divisions (1)
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Number |
Date |
Country |
Parent |
814266 |
Dec 1991 |
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