during mechanical polishing is therefore removed. Figure 4 shows two pairs of electron micrographs and EBSD patterns [9]. The effects of polishing time on the pattern quality are observed. It indicates that silica polishing needs a very long time to reach a good surface. From the experience in our group, silica polishing works for materials with very high atomic number and the image quality obtained from this method is obviously lower than that of the same material polished by electropolishin