Ceramics-Silikáty 35, (3) 193 - 200 (1991)

The currently used blue emitting luminophore was proved not to contain the (Ba, Eu)Mg₂Al₁₆O₂₇ aluminate as is often stated in the literature. An initial mixture, corresponding by its composition to the formula given above, yields a mixture of α-Al₂O₃ and the aluminate Ba_0.72(1-x)Eu_0.72xO_0.28 Mg_1.44Al_10.08O₁₇(Ba_1-xEu_xMg₂Al₁₄O₂₄) with a structure of β-Al₂O₃. The structure was found to contain arranged O_Ba atoms and was compared to the structure of similar aluminates. The luminophore is conveniently prepared by heating the coprecipitated hydroxides or hydrated oxides at 800-1000 °C and subsequent igniting in a mildly reducing atmosphere (N₂ + H₂) at high temperatures. In access of atmospherical oxygen, the Eu³⁺ containing aluminate being formed is stabilized by additional O atoms built into its structure. The luminophore exhibits maximum emission in the blue region at an Eu²⁺ content of x = 0.11.