Novel silicon carbide-modified graphite electrodes for enhanced performance in gas switches

This study proposes a novel surface modification technique using silicon carbide (SiC) to significantly improve the breakdown stability of graphite electrodes in gas switch applications. We employed chemical vapor infiltration to modify the surface of graphite electrodes with silicon carbide, forming a dense and uniform SiC coating on the electrode surface. Through comparative electron emission experiments and self-breakdown tests, the electrical characteristics of pristine graphite electrodes and SiC-modified counterparts were systematically investigated. Results demonstrate that SiC modification substantially enhances electrode performance: the modified electrodes exhibit a 10% higher threshold electric field (increasing from 208.4 kV/cm to 229.2 kV/cm) and a reduced surface field enhancement factor, indicating significantly suppressed inhomogeneous electron emission. Furthermore, under identical operating conditions, switches equipped with SiC-modified electrodes achieved an 8.7% higher average breakdown voltage (36.62 vs 33.69 kV) with a 52% reduction in relative standard deviation (2.15% vs 4.50%), confirming superior breakdown stability. Scanning electron microscopy analysis revealed that the SiC-modified layer maintains uniform and compact micro-morphology pre- and post-experiment, indicating improved mechanical robustness. These findings collectively validate SiC modification as an effective strategy for optimizing graphite electrode performance in high-stability gas discharge switching systems.