COEXISTING CRYSTALLINE SOLUTION PHASES ACTIVATED BY DIVALENT EUROPIUM

摘要

1284453 Luminescent materials and uses thereof GTE SYLVANIA Inc 4 Aug 1969 [5 Aug 1968] 38971/69 Heading C4S A luminescent material comprises two coexisting crystalline solution phases activated by divalent Eu, one phase being spinel (MgAl 2 O 4 ) partially substituted by Si, the other being corundum (αAl 2 O 3 ) partially substituted by Si and Mg, the Eu being present in the range 0À001 to 0À20 gram atoms per gram mole of the two hosts combined. The corundum phase may have the formula where w is 0 and up to the limit of solubility of SiSP4+/SP and MgSP2+/SP in corundum and v is between 0À001 and 0À20 and the spinel phase has the formula (MgSP2+/SP 1-2x-y SiSP4+/SP x#x )SPIV/SPAl 2 SP3+VIO/SP4:EuSP2+/SP y where # represents the vacancies formed in the cation lattice to preserve electro neutrality, y is 0À001 to 0À20 and x is greater than zero and up to the solubility limit of SiSP4+/SP in MgAl 2 O 4 . In preparation, alumina, magnesium carbonate, silica acid and europium nitrate for example, may be blended with glassbeads, fired in an alumina boat at 650‹ C., fired in a tube furnace at 1100‹ to 1300‹ C. in a reducing atmosphere of hydrogen and nitrogen, and the fused silica tube then removed from the furnace and cooled in the reducing atmosphere. Exemplified formulations are 0À99 Al 2 O 3 .0À01 SiO 2 .0À01 MgO: EuSP2+/SP 0À01 ; 0À95Al 2 O 3 . 0À05 SiO 2 . 0À05 MgO: EuSP2+/SP 0À01 ; 0À90 Al 2 O 3 . 0À10 SiO 2 . 0À10 MgO: EuSP2+/SP 0À01 ; and 0À08 Al 2 O 3 . 0À20 SiO 2 . 0À20MgO: EuSP2+/SP 0À01 ; Fluorescent, low and high pressure mercury lamp applications are instanced and blends with other phosphors mentioned.