The surface morphology ofintermetallic particles present in Peraluman 706TM, AA1090 and AA6060 after steam treatment with the steam generated from 4 g/l KMnO4 is shown in Fig. 5(c), (d) and (f). The steam treatment resulted in the formation of needle like structure over the intermetallic particle and extended up to the aluminium matrix. Further, aluminium matrix around the intermetallic particles also showed the presence of flower like structures having size within 0.1–0.5 m. The amount of K detected by EDS analysis over intermetallic particles after steam treatment with aqueous solution of KMnO4 was much less when compared to sample treated by dipping in KMnO4 at 85 ◦C.