Phase diagram at low temperature of the system ZrO2/Nb2O5

Various compositions of the ZrO2/Nb2O5 system were synthesized and the expe rimental conditions for obtaining reproducible results were established. Th e gel was precipitated at constant pH = 10, aged at room temperature for 18 h and, after filtration, dried at 110 degreesC for 24 h. The phase diagram of the ZrO2/Nb2O5 system was established between 600 and 1300 degreesC. Ph ase transitions of ZrO2 and Nb2O5 were observed with XRD; and two ternary c ompounds, 6ZrO(2). Nb2O5 and 12Nb(2)O(5). ZrO2, were identified. The sample s with a Nb2O5 content between approximately 10 and 40 mole% showed the gre atest specific area and are thus best for use as catalyst supports.