The Bi2O3-Nb2O5-NiO phase

The Bi2O3-Nb2O5-NiO phase diagram at 1100 degrees C was determined by means of solid-state synthesis, X-ray diffraction, and scanning electron microscopy. A ternary eutectic with a melting point below 1100 degrees C was found to exist in the field between NiO, Bi2O3, and the end-member of the delta Bi2O3-Nb2O5 solid solution. The existence of the previously reported Bi3Ni2NbO9 phase was disproved. A pyrochlore homogeneity range around Bi1.5Ni0.67Nb1.33O6.25 was determined together with all the phase relations in this phase diagram.