Radiation effects in nonmetals: Amorphization, phase decomposition, and nanoparticles

Radiation effects in nonmetals have been studied for well over a century by geologists, mineralogists, physicists, and materials scientists. The present work focuses on recent results of investigations of the ion-beam-induced amorphization of the ABO4 compounds--including the orthophosphates (LnPO4; Ln = lanthanides) and the ortho-silicates: zircon (ZrSiO4), hafnon (HfSiO4) and thorite (ThSiO4). In the case of the ortho-silicates, heavy-ion irradiation at elevated temperatures causes the precipitation of a nanocrystalline metal oxide. Electron irradiation effects in these amorphized insulating ceramics can produce localized recrystallization on a nanometer scale. Similar electron irradiation techniques were used to nucleate monodispersed compound semiconductor nanocrystals formed by ion implantation of the elemental components into fused silica. Methods for the formation of novel structural relationships between embedded nanocrystals and their hosts have been developed and the results presented here demonstrate the general flexibility of ion implantation and irradiation techniques for producing unique near-surface microstructures in ion-implanted host materials