Effect of mechanical prestress on the dielectric strength of alumina

the objective of this work is to provide new information on correlation between mechanical and electrical properties of alumina (Al
₂
O
₃
), particularly the understanding of the dielectric breakdown mechanism. We propose to study the impact of the mechanical prestress on the short-term dielectric strength of the ceramic. Flexural stress is applied to induce or propagate cracks within alumina plates of 635 μm. We assume that the mechanical prestress impacts the initial crack size in the material, hence diminishing the breakdown voltage according to the electromechanical breakdown model.