| abstract |
A superstoichiometric MgAl 2 0 4 spinel, which can be used, for example, as material for a high temperature crucible, is synthesized by, producing a precursor mixture comprising intimately mixed oxides of the corresponding metals in the spinel. Magnesium is added in a superstoichiometric amount to the precursor mixture. Prior to spinel formation, from one to five percent by weight of a reactive salt containing fluorine and/or boron, based on the metal oxides of the spinel, are added to the precursor mixture, and the doped precursor mixture is mixed for from 0.5 to 3 hours. Finally, the mixed precursor mixture is heated for between 0.5 and 4 hours at a temperature between 1150° C. and 1400° C. to synthesize the Mg.sub.(1+x) Al 2 0 4 spinel which is superstoichiometric with respect to magnesium. |