Ultramicrotomy of nanocrystalline materials

The methodology and one of the first attempts to produce transmission electron microscopic (TEM) specimens of nanocrystalline metals, alloys and ceramics by ultramicrotomy are presented. Samples of the pure elements Co, Pd; alloys of Y-12 at. % Fe, Al-7 at. % Ag and W-30 at. % Ga; and ZnO ceramic, were found to section successfully to varying degrees. Advantages of sections prepared through ultramicrotomy over ion beam methods include extensive electron-transparent regions of uniform thickness and absence of ion beam damage. Typical artefacts were observed (knife marks, tearing, pull-out, shear lamellae, section curling, and anodic dissolution) but did not impede TEM analysis significantly. A potentially important effect observed was that of a texture development upon sectioning of the Co and Pd samples. It is thought that this unusual phenomenon results from the extremely fine scale of the microstructure and the purity of the Co and Pd samples, and may be enhanced by frictional heating effects and the state of the knife edge.