The mechanisms and kinetics of the processes at the Bi2O3/Y2O3 interfa
ce were studied by x-ray diffraction and microstructural analysis. Phy
sicochemical modeling of separate reaction stages demonstrates that th
e reaction of Bi2O3 and Y2O3 involves a number of parallel elementary
reactions, which are kinetically limited and associated mainly with di
ffusion of the components of Bi2O3.