The Occupation Behavior of Y 2 O 3 and Its Effect on the Microstructure and Electric Properties in X7R Dielectrics

The occupation behavior of Y 2 O 3 in nonreducible BaTiO 3 ‐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 Y 2 O 3 , 0.50 mol% and 1.00 mol%, and the latter is the solubility limit. Below 0.50 mol%, the introduced Y 3+ 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 Y 3+ ions will turn to occupy B sites to substitute for Ti 4+ ions, leading to the significant reduction in dielectric constant and energy storage density. Above the solubility limit of 1.00 mol%, the excess Y 3+ ions would segregate at grain boundary and even induce the formation of Y 2 Ti 2 O 7 phase, resulting in an abrupt enhancement of grain‐boundary resistance. Doped with 0.75–1.50 mol% Y 2 O 3 , all nonreducible specimens meet X7R requirement.