Secondary ignition of carbon-based bridge coating triggered by low voltage

Abstract

With the goal of reducing ignition voltage, a new type of carbon-based bridge coating (CBBC) was prepared, and its ignition performance was investigated. The size of the bridge area with the lowest ignition voltage was determined, and a secondary ignition phenomenon that occurred during the experiment was analyzed. Self-made conductive carbon paste was printed on the Al2O3 substrate by a screen printing process, and the ignition bridge was shaped using laser etching technology. Both ends of the CBBC were coated with conductive silver paste and lead on their electrodes. A stabilized DC power supply was used for the ignition experiment. The ignition performance of the CBBCs under different bridge sizes was measured, and scanning electron microscopy (SEM) characterization and analysis were performed on the surface of the ignition bridge area before and after the experiment. The CBBCs with a bridge area size of 300 × 300 μm could be ignited at or under 24 V, and only part of the CBBCs could be triggered when the bridge area size was 500 × 500 μm. Further, the ignition voltage may have been influenced by the poor uniformity of the coating thickness. Overall, the results demonstrate the following: (1) The CBBCs prepared in this experiment could be fully ignited at a voltage of 24 V, (2) a bridge size of 300 × 300 μm could ensure stable ignition with low voltage, and (3) the tip discharge caused by the first fuse of the CBBCs was the root cause of the secondary ignition.