Method of improving the maintenance of a fluorescent lamp containing terbium-activated cerium magnesium aluminate phosphor

Claim 1

A process for improving the maintenance of a fluorescent lamp containing terbium-activated cerium magnesium aluminate phosphor having the general formulation CeMgAl 11 I 19 :Tb, comprising the steps of: a) combining a terbium-activated cerium magnesium aluminate phosphor with small particle size aluminum oxide having a particle size of 0.02 micrometers in an amount of about 0.1% to about 0.4% by weight of said phosphor to form a uniform mixture; b) wet-milling said mixture in water in an amount of about 0.35 gallon of water per pound of said phosphor for about 15 minutes; c) wet-screening said mixture to remove particles greater than 25 micrometers in diameter; d) removing said water from the wet-screened mixture by filtering and drying said wet-screened mixture to form a dry milled phosphor; e) deagglomerating said dry milled phosphor to obtain a stir-in terbium-activated cerium magnesium aluminate phosphor; and f) coating the interior of a fluorescent lamp envelope with said stir-in terbium-activated cerium magnesium aluminate phosphor.