Failure mechanisms of BaTiO3-Based multilayer ceramic capacitors under coupled impact and high electric field: The role of microstructure and electromechanical coupling

The operational reliability of high-voltage multilayer ceramic capacitors (MLCCs) under simultaneous mechanical impact and high electric field is critical for pulsed power systems. This study investigates the failure mechanisms of BaTiO 3 -based MLCCs using a custom-developed synchronous charging and impact testing system based on the Split Hopkinson Pressure Bar. Results reveal a critical impact velocity of 7.95 m/s, demarcating two distinct failure modes. Below this threshold, failure occurs through cumulative microdamage from multiple stress pulses. Above it, a single stress pulse causes immediate catastrophic dielectric breakdown. Furthermore, the applied electric field significantly weakens mechanical integrity, reducing the fracture strength by up to 34% as the voltage increases from 500 V to 1300 V. This catastrophic failure is attributed to a synergistic electromechanical coupling effect: the impact stress wave induces microcracks and piezoelectric voltage spikes, which collectively cause severe local electric field distortion. The enhanced field, concentrated at internal electrode edges and material defects, then triggers an electron avalanche discharge, culminating in dendritic breakdown channels and material ablation. These findings provide crucial insights for designing high-reliability MLCCs for extreme electromechanical environments.