COMPATIBILITY OF INSULATING CERAMIC WITH LIQUID BREEDERS

The compatibility of candidate materials for insulating ceramic coatin gs (Y2O3, Al2O3, MgO, 3Al(2)O(3)-MgO, AlN (60%)-BN (40%) and BN) with liquid metal breeders such as metallic lithium and lithium-lead alloy (Li17-Pb83) was investigated at 773 K up to 5 Ms by monitoring weight change, structural integrity and electrical resistivity. Oxides such a s Al2O3 and 3Al(2)O(3)-MgO were severely corroded and dissolved or bro ken by lithium, while MgO was corroded uniformly with a moderate rate (e.g. 27 mu m for 4.8 Ms). The most thermodynamically stable Y2O3 was less corroded and showed a slight decrease in electrical resistivity d ue to the formation of non-stoichiometric Y2O3-x. On the other hand, n o oxides were corroded at all by Li17-Pb83. These results were in good agreement with thermodynamical predictions, and most of the oxides ma intained their high electrical resistivity even after the corrosion te st in liquid lithium. Nitrides such as AlN-BN and BN were corroded by lithium and became fragile because impurities included in the specimen s were dissolved in the lithium. (C) 1998 Elsevier Science B.V.