IMAGING OF THIN INTERGRANULAR PHASES BY HIGH-RESOLUTION ELECTRON-MICROSCOPY

We discuss the imaging of thin amorphous intergranular films by high-resolution electron microscopy. The thin films can either be imaged indirectly as gaps between two crystalline grains, or directly by dark-field imaging of the diffuse scattering due to the amorphous phase. The new direct method is shown to be much less dependent on defocus and boundary orientation than previous methods. It is also capable of precise determination of the boundary film thickness, and is much easier experimentally than other methods.