Most of mold manufacturing procedures have been automated by the introduction of NC machine tool and CAD/CAM system. But the three dimesional surface curvature of the mold must be done by hand work of well-skilled workers. Magnetic abrasive polishing method was investigated for surface polishing for 3D curvature. Recently, the technology for internal polishing is needed to ultra-clean machine method for the purpose of corrosion, pollution prevention of parts in the area of high technology industry such as semiconductor, electronics and telecommunication.
In this study, Magnetic Abrasive composed of A(Fe₃O₄+Al = 3:1wt.%):B(Fe +65vol.%Al₂O₃) and A:B(5:5, 6:4, 7:3, 8:2, 9:1 wt.%) powder was developed. Ball milling was operated in the ratio of ten to one for ball and powder by 100rpm for one hour in the atmosphere. Fe-Al₂O₃ composite powders was prepared by self-propagating high temperature synthesis. Characterization and surface properties were investigated by means of OM, XRD, SEM, EDS and Vickers hardness tester. As the amount of Fe₃O₄+Al increase, the grain size of Al₂O₃ becomes fine and the distribution in the matrix(Fe) gets uniform. Because of Al₂O₃ grain refining and the decrease in the grain size of Fe, the matrix in the composition ratio of nine to one, hardness was shown to highest value.