Novel sintering technology yields ultrahigh voltage-gradient ZnO-based varistor ceramics, widely used in overvoltage protection

https://www.eurekalert.org/news-releases/1080678

"enhances voltage gradient without compromising other performances... low temperature densification hybrid cold sintering/ spark plasma sintering and post-annealing process reduces energy consumption, enables fine/ homogeneous microstructure, prevent Bi-rich phase volatilization at grain boundaries, ultrahigh ~1832.71 V/mm voltage gradient, high ~106.69 nonlinear coefficient, low <0.2 μA/cm² leakage current density... high-resistance grain boundaries producing increased Schottky barrier height, better performance"