Alumina ceramics

owing to their excellent electrical and mechanical properties

are widely employed as enclosure materials in high-voltage vacuum interrupters

where they serve critical roles in insulation

structural support

and vacuum sealing. However

surface flashover along ceramic surfaces inside the interrupter significantly degrades insulation performance. At present

the predominant strategy to enhance ceramic insulation is to increase its length

which unfortunately leads to larger interrupter dimensions and higher production costs. Therefore

improving the surface flashover voltage per unit length under vacuum conditions is essential for reducing device size and cost while enhancing operational reliability. We put forward a novel approach involving the fabrication of periodically etched triangular grooves on alumina ceramic surfaces to enhance vacuum surface flashover voltage. A systematic investigation was conducted to evaluate the influence of groove periodicity (ranging from 100 μm to 400 μm) under direct current (DC) voltage. Furthermore

a simulation model based on the particle-in-cell with Monte Carlo collision (PIC-MCC) algorithm was developed to explore the flashover mechanism

and experimental results were used to validate the suppressive effect of the micro-grooved structure. The findings reveal that surface microstructuring can effectively enhance flashover performance. Specifically

for the sample with a groove period of 100 μm

the 50% flashover voltage increased from 26.37 kV (ungrooved) to 40.18 kV

representing an improvement of 52%

which offering a promising direction for the structural optimization of ceramic enclosures in vacuum interrupters.