High temperature erosion of beryllium

The erosion behavior of solid beryllium surfaces exposed to plasma bombardment at high temperature is investigated. The experimentally measured erosion rate of surfaces exposed to energetic particle bombardment at elevated temperature exceeds that predicted by a summation of the physical sputtering rate and the thermodynamic sublimation rate. A model based on the creation of surface adatoms, due to energetic projectile bombardment of surfaces, and their subsequent sublimation is used to explain the enhanced erosion. Molecular dynamics (MD) simulations of beryllium confirm that the experimentally measured evaporation energy (∼2 eV) is consistent with the binding energy of adatoms. Of critical importance in this model is the creation rate of adatoms during the surface bombardment. The experimental dependence of the increased erosion on the incident particle flux, particle species and incident particle energy is presented and discussed in relation to the adatom model.