Preparation of radiation damaged ceramic powders by ion bombardment

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Abstract
Ceramic powders can be prepared in a radiation damaged condition by bombardment with 1 to 4 MeV ions of Ne, Ar, Kr or Xe. The powder particle sizes are chosen to correspond to the ion beam penetration but are found to be considerably greater than the calculated ion ranges for powders becoming metamict. A monolayer of powder particles of sizes up to about 5 μm is sedimented onto long strips of metal foil with an area density of about 1 mg-cm-2. The ion beam is rastered to irradiate an area as the foil rotates on a drum through the beam. Alternately, monolayers of powder particles can be prepared by the use of a very-thin layer of rubber cement. By these techniques, plates can be prepared for irradiation in the ion beam and also for direct insertion into an X-ray diffractometer. Gram amounts of irradiated material can be collected in a few hours for studies such as powder X-ray diffraction, SEM, Differential Scanning Calorimetry and density measurements. Thus, zircon ZrSiO4 becomes non-crystalline or metamict under ion bombardment with a damage cross-section DM = 0.33 nm-2 for Ar (3 MeV) ions; one gram can be rendered 50% non-crystalline after two hours of irradiation by a 6 μA ion beam.