Excellent cyclic ablation resistance of MoAlB ceramics under nitrogen plasma flame at 2000 °C

Abstract

Thermal protection materials (TPMs) are crucial in advancing aerospace technology. In order to explore the applicability limits and reusability of MoAlB ceramics used as TPMs, the cyclic ablation performance and mechanisms were studied in a nitrogen plasma flame at about 2000 °C. After 1 to 5 ablation cycles (5 min per cycle), MoAlB ceramics retained their structural integrity. The linear and mass ablation rates were measured as 4.73 µm/s and 2.98 mg/s, respectively, after five ablation cycles (total of 25 min). The ablation resistance of MoAlB ceramics was primarily ascribed to the oxidation layer formed through their decomposition and oxidation. As the cycles extended, the plasma flame gradually damaged the oxide layer and led to the erosion and failure of the MoAlB matrix. Nevertheless, MoAlB ceramics exhibit exceptional resistance against cyclic and long-duration ablation, rendering it a highly promising application for TPMs.