Microstructure analysis of the Y5V multilayer ceramic capacitors based on BaTiO3

The Y5V-1206 base-metal electrode (BME) multilayer ceramic capacitor (MLCC) chips have been characterised for crystalline phases using X-ray diffractometry (XRD), and microstructure using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microstructure features found in the Ni electrode and the BaTiO₃ dielectric layer are discussed in terms of the tensile backstresses induced upon firing due to constrained sintering heterogeneously. The chemical compositions containing BaO-excess and additives CaO and ZrO₂, determined for BaTiO₃ grains by energy-dispersive spectroscopy (EDS) equipped in the TEM are also reported. However, no rare-earth oxides were found in the grains. The representative microstructure of BaTiO₃ grains containing dislocations is the “solid-solution” type distinctive from the “core-shell” of the X7R compositions. The fact that no ferroelectric domains were detected suggests that the BaTiO₃ grains are pseudo-cubic with the c/a ratio ≈ 1.0.