A high-resolution electron microscopic study was made of a sintered β-phase specimen which had been heavily neutron-irradiated in a fast reactor. A new type of planar defect, which lay on {11•0} planes, was observed. The defect could be described as being an interstitial dislocation loop with a Burgers vector of about 1/6<223>. This corresponded to an extra layer of SiN4 tetrahedra which was inserted into {11•0} planes.

A New Type of Defect on {11•0} Planes in β-Si3N4 Produced by Neutron Irradiation. M.Akiyoshi, T.Yano, M.L.Jenkins: Philosophical Magazine Letters, 2001, 81[4], 251-8