Inclusions of BeO are of tremendous importance on the mechanical properties of Beryllium [1,2]. The BeO particle sizes of different hot pressed materials are in the range between 400 Å and 10 μm for BeO contents between 0.5 and 3.6%[3]. However, there is no investigation about the BeO dispersion in high purity (<200 ppm BeO) ingots. Information on this subject should be derived from the diffuse Debye rings of BeO, which as yet are thought to come from the very thin oxide scale on the Be-surface [3].0.1 mm foils of Berylco IF—1 from KBI with BeO < 200 ppm were analyzed at 100 kV in the as received condition or after annealing for 1 hour at 900°C in ultrahigh vacuum. With the electron beam parallel to [00.1], [11.1], [02.1], [12.1], [03.1], [12.2] (using different grains) always four diffuse BeO rings of the type {10.0}, {10.1}, {11.0}and the unresolved {20.0}/{11.2} appear in the SAD-pattern.
