Nanocrystalline oxides which had been prepared by ball-milling were studied using high-resolution transmission electron microscopy. It was found that the image contrast and diffraction of these nano-particles were not significantly different to those of crystalline materials. Well-defined grain boundaries were observed, and only rarely were crystal defects found. On the other hand, disordered areas and amorphous regions were frequently seen around, and between, crystalline particles.

D.Michel, L.Mazerolles, E.Gaffet: Materials Science Forum, 1997, 235-238, 601-6