Abstract
Several silicates, and alpha and beta Si3N4, AlN and ZrN have been irradiated by 1019-1021Kr (3MeV)ions/m.2 The damaged powders of original particle size less than 5 mu m, have been examined by x-ray diffraction and elecron microscope methods. The nitrides behave quite differently from the silicates, even at fluences of 200 x 1019 ions/m2 the former remain crystalline, retaining relatively sharp edges to the particles without exhibiting irradiation creep. This difference in behaviour can be related to the nature of the framework crystal structures flexible for the silicates with variable bond angles, rigid for the nitrides with fixed bond angles. This may explain the behaviour of radioactive minerals not found in a metamict condition. 30 ref.--BA