Ion-induced amorphization in ceramic materials

Amorphization induced by swift heavy ions is discussed, the main features are reviewed and explained by the author’s model. In Al₂O₃ and MgAl₂O₄ the recrystallization reduces considerably the track diameters. The threshold electronic stopping power for amorphization S_et can be estimated reliably for these solids from the position of the amorphous-crystalline boundary formed at high ion fluences. The results are in good agreement with the predictions of the model. Experiments on CeO₂ and UO₂ are discussed. Estimates of S_et are made for β-Si₃N₄, CeO₂, pure ZrO₂, ZrSiO₄, and UO₂, and 10.1 > S_et > 6.2 keV/nm is obtained at room temperature for fission fragment energies. At about 1000 °C operation temperature, S_et is reduced by about 35-50%. No amorphization is expected by ion bombardment in AlN, SiC (semiconductors) and MgO (ionic crystal).