The Occupation Behavior of Y2O3 and Its Effect on the Microstructure and Electric Properties in X7R Dielectrics

The occupation behavior of Y2O3 in nonreducible BaTiO3‐based ceramics was investigated thoroughly. Based on XRD, SEM, TEM‐EDS, and complex impedance analysis, it is ensured that there exists two turning points of Y2O3, 0.50 mol% and 1.00 mol%, and the latter is the solubility limit. Below 0.50 mol%, the introduced Y3+ ions precede to enter the A sites of the perovskite lattice, causing an observed enhancement in dielectric constant and energy storage density accompanied by an increase in grain size. Once the addition exceeds 0.50 mol%, the Y3+ ions will turn to occupy B sites to substitute for Ti4+ ions, leading to the significant reduction in dielectric constant and energy storage density. Above the solubility limit of 1.00 mol%, the excess Y3+ ions would segregate at grain boundary and even induce the formation of Y2Ti2O7 phase, resulting in an abrupt enhancement of grain‐boundary resistance. Doped with 0.75–1.50 mol% Y2O3, all nonreducible specimens meet X7R requirement.