Abstract: An improved method for a single step firing synthesis of borate phosphors wherein at least about half the amount of a volatile, low melting point, boron source such as boric acid or boron oxide is replaced with an equivalent amount of boron nitride. The method having the advantages of a single step firing and providing better control over the stoichiometry of the phosphor.

Abstract: A surface modified phosphor powder exhibiting increased lumen maintenance. At the outer surface of each phosphor particle, the cations of the phosphor material have been replaced by other cations, e.g., a metal or metalloid cation such as aluminum, barium, calcium, lanthanum, magnesium, strontium, yttrium, zinc, titanium, tantalum, boron, or silicon. The phosphor powder is chemically modified by forming a suspension of phosphor particles in a liquid medium including the metal or metalloid ions in solution. The phosphor suspension is stirred for a time sufficient to permit an ion exchange reaction in which the metal or metalloid ions are substituted for cations of the phosphor to form a layer of the desired metal or metalloid compound at the phosphor outer surface.

Abstract: Small-sized, high brightness (La,Ce,Tb) PO.sub.4 phosphors having an average particle size of less than about 4.0 microns can be made by adding boric acid and lithium carbonate to the rare earth phosphate co-precipitate prior to firing. The small-sized, high brightness phosphors have a brightness equivalent to or greater than larger-sized phosphors of the same composition.

Abstract: Metal phosphide used as a raw material in the synthesis of alkaline earth metal halophosphate phosphor activated by antimony and manganese acts as a reducing agent to prevent oxidation of the antimony and manganese. The result is maximum availability of trivalent antimony and divalent manganese for incorporation into the phosphor lattice.

Abstract: Metal phosphide used as a raw material in the synthesis of alkaline earth metal halophosphate phosphor activated by antimony and manganese acts as a reducing agent to prevent oxidation of the antimony and manganese. The result is maximum availability of trivalent antimony and divalent manganese for incorporation into the phosphor lattice.

Abstract: A lanthanum cerium terbium gadolinium phosphate phosphor has the composition La.sub.1-x-y-z Ce.sub.x Tb.sub.y Gd.sub.z PO.sub.4, where x=0.2 to 0.45, y=0.127 to 0.137, and z=0.001 to 0.1. The phosphor has improved brightness and/or maintenance over a lanthanum cerium terbium phosphate phosphor without gadolinium. The phosphor can be prepared by reacting a lanthanum cerium terbium gadolinium oxide with boron phosphate in the presence of a flux forming compound containing lithium in an inert or reducing atmosphere.