Ion Implantation Damage Processes in Nuclear Waste Glass and Other Silicate Glasses

Abstract

AbstractCantilever beam measurements of induced lateral stress have been made for He, Xe and Pb ion-implantation into the complex borosilicate radioactive waste glasses (PNL 76–68, SRP), a commercial borosilicate (Pyrex), and into fused Si02 (Suprasil 1). For the borosilicate glasses, implantation caused a buildup of stress to a saturation value (∼ 1 × 105 dynes/cm). The maximum occurred at ion fluences greater than those found for maximum stress in fused silica and without a stress relief mechanism. The separate family of stress curves for Pyrex and PNL 76–68 coincide when stress is plotted as a function of energy into electronic processes. Pyrex has 13 wgt.% B2O3 and 81 wgt.% SiO2, while PNL 76–68 and SRP have 10% B2O3, 40% SiO2 and N5 B2O3 and 58% Si0 2, respectively. Pyrex is known to be phase-separated, and Ghe waste glasses are susceptible to phase separation. It is suggested that the B2O3 phase may be more easily compacted than the SiO2 phase. The evidently greater effectiveness of the ionization component of the ion energy in creating damage in borosilicate glasses should be of considerable interest in waste glass studies because of the large amounts of ionization from α-decay (∼ 5 MeV He).