Influence of Surface Carburization of Machinable Ceramics on Its Pulsed Flashover Characteristics in Vacuum

Abstract

For pulsed power devices, surface flashover phenomena across solid insulators greatly restrict their overall performance. In recent decades, much attention has been paid on enhancing the surface electric withstanding strength of insulators, and it is found that surface treatment of material is useful to improve the surface flashover voltage. The carburization treatment is employed to modify the surface components of newly-developed machinable ceramics (MC) materials. A series of MC samples with different glucose solution concentration (0%, 10%, 20%, 30% and 40%) are prepared by chemical reactions for surface carburization modification, and their surface flashover characteristics are investigated under pulsed voltage in vacuum. It is found that the surface carburization treatment greatly modifies the surface resistivity of MCs and hence the flashover behaviors. Based on the reduction of surface resistivity and the secondary electron emission avalanche (SEEA) theory, the adjustment of flashover withstanding ability can be reasonably explained.

Design and 3D printing of porous cavity insulation structure for ultra‐high electrical withstanding capability

“…It is worth noting that the voltage waveforms and electrode types used in flashover voltage testing in representative literatures selected for comparison are the same or similar to those in this study. Clearly, the cavity insulation structures exhibit ultra‐high surface insulation improvement ratio in both the cases of DC [26, 27, 46, 50–54] and impulse [24, 28, 35–38, 46, 55–59] flashover, which far outperform the other flashover mitigation strategies.…”

Trap distribution of polymeric materials and its effect on surface flashover in vacuum

“…It severely limits the service life and operational reliability of power equipment. Through the secondary electron emission avalanche (SEEA) model, we know that surface trapping can participate in the development of SEEA and significantly affect the surface flashover characteristics of insulating materials in vacuum [1][2][3][4][5]. In the theory of electron triggered polarization relaxation (ETPR), trapped charge is also the main cause for vacuum surface flashover [6,7].…”