Crack suppression behavior with post-process parameters in BaTiO3-based Ni-MLCCs

Effects of post-process parameters, such as temperature, holding time, and pressure direction, on crack evolution are investigated in BaTiO3-based multilayer ceramic capacitors (MLCCs), showing X7R characteristic. Vickers indentation is conducted at each plane of the MLCCs before and after the post-process. Crack evolution in the MLCCs is definitely suppressed through the post-process. Difference of crack length between directions at same plane is also reduced through the post-process. The minimum crack length after the post-process is 19 ± 4 μm and 12 ± 5 μm at the x plane, 23 ± 7 μm and 13 ± 3 μm at the y plane, and 14 ± 2 μm and 19 ± 8 μm at the z plane in the parallel and perpendicular directions to the electrode, respectively. Holding time in the post-process with width direction affects the crack formation within an error range, showing shorter crack length in perpendicular direction rather than in parallel direction to the electrode. Higher temperature, 900 °C, is relatively more effective in reducing crack length than lower temperature, 600 °C, especially at the x plane. The post-process with width direction for the x and z planes and length direction for the y plane is more useful for reducing crack length or suppressing crack propagation.