PRECURSOR COMPOUNDS OF ALKALINE EARTH METAL OR RARE EARTH METAL ALUMINATES METHOD FOR PRODUCTION AND USE THEREOF PARTICULARLY AS PRECURSORS FOR LUMINOPHORES

摘要

The invention relates to a precursor compound of an alkaline earth metal or a rare earth metal aluminate of formula: a(M<1>O).b(MgO).c(AI2O3) or a(M<2>O1.5).b(MgO).c(AI2O3), where M<1> = an alkaline earth metal and M<2> = yttrium or a combination of cerium and terbium and a, b et c are either whole numbers or not and obey the relationships: 0.25 = a = 4; 0 = b = 2 et 0.5 = c = 9, crystallized in the form of a transition alumina comprising essentially spherical and chemically homogeneous particles. Said particles have pores the average diameter of which is less than 10 nm. The above is obtained by a method in which a liquid mixture is formed comprising compounds of aluminium and other elements present in the composition of the precursor, said mixture is dried by atomisation and the dried product calcinated at a temperature between 700 DEG C and 950 DEG C inclusive. An alkaline earth metal or a rare earth metal aluminate is obtained by subsequent calcination of the product obtained.