Electron-stimulated processes in boron nitride-based ceramics

The low-energy electron radiation resistance of boron nitride-based BN + Si₃N₄ and BN + SiO₂ ceramics proposed as a construction material for ion space engines was studied. It was shown that a reduced silicon phase is formed on the BN + Si₃N₄ ceramics surface in the high-temperature region (～900 K), which results from material thermal destruction. The BN + SiO₂ ceramics exhibits high thermal stability and is not prone to destruction due to electron-stimulated oxygen desorption (the cross section of this process does not exceed 10^?20 cm²). It is preferable to use such ceramics as a construction material. Based on the results obtained, some models were proposed that explain variations in the erosion rate of ceramic units of ion engines under electron and ion irradiation.