par Mwamba, Kitembo ;Verwerft, Marc;Duvigneaud, Paul-Henri
Référence Key engineering materials, 264-268, II, page (1051-1054)
Publication Publié, 2004
Article révisé par les pairs
Résumé : The pseudoquaternary system UO2-BaO-ZrO2-MoO x (where x = 0, 2, 3) was studied in the temperature range 1480°C-1600°C at oxygen pressures corresponding to reducing (x=0) and oxidizing (x=2,3) conditions for molybdenum. Ternary BaO-ZrO2- MoOx compositions were mixed with UO2 in proportion of 80 wt% UO2. In reducing conditions (pO2=10-16 atm), Mo0 is in equilibrium with the U1-xZr xO2 matrix and the Ba(ZrUMo)O3 perovskite phase. In oxidizing conditions (pO2 =10-9 atm), BaO reacts preferably with MoO3 giving the scheelite BaMoO4 phase. For Ba/Mo<1, MoO2 is also formed. For Ba/Mo>1, the perovskite phase is replaced by a new uranate phase of composition Ba2(U 1-x Zrx)3O9+y with y<0.5 wherein UIV is oxidized into Uv. Mo and U oxidation occur in the same pO2 range,e.g between 10-12 and 10-9 atm.