1993 Volume 34 Issue 4 Pages 343-350
The surface layers of Mn–Zn ferrite single crystals finished by polishing with a diamond powder were examined by ultra-microhardness testing, scanning electron microscopy and transmission electron microscopy. The change in the hardness and Young’s modulus traced by the ultra-microhardness testing by removing surface layer step by step by chemical etching showed that the depth of the surface layer by the finishing process depends on crystal orientation. The depth was evaluated to be around 2.5 μm for the (110) crystal and much less than 2.5 μm for (111) crystal surfaces, respectively. The dislocation structures with characteristic feature were found to arrange along several crystal orientations with low indices in the surface layer. The fractography by scanning electron microscopy on fractured surfaces of broken specimens, hardness testing and Young’s modulus measurement suggest the existence of the defects such as microcracks in the surface layer.
