Melting behaviors of pyrochlores in Bi2O3-ZnO-Nb2O5system

The melting behaviors of pyrochlores in Bi2O3-ZnO-Nb2O5 system have been investigated. The main crystal structures in Bi2O3-ZnO-Nb2O5 system include a cubic pyrochlore (α), a monoclinic pyrochlore (β) and a defect cubic fluorite (F). The α pyrochlore and F fluorite are congruent melting compounds and the β pyrochlore is an incongruent melting compound. The melting temperature of α pyrochlore is 1187°C. The β pyrochlore decomposes to α pyrochlore, F fluorite and liquid phase at 1100°C. A secondary peritectic reaction that the liquid phase absorbs α phase and F phase to precipitate β phase happens when the temperature is cooling down.