Microstructure Characterisation and Magnetic Properties ofNanocrystalline Cu-Fe-Co-AI-2O-3 Composite Powders Processed byMechanical Alloying

摘要

The effects of AI-2O-3 addition on structural and magnetic property changes during mechanical alloying of Cu, Fe and Co have been studied systematically by Electron microscopy (SEM-EDS), X-ray diffractometry (XRD) and SQUID magnetometry. Milling the powders up to 10h leads to the progressive dissolution of Fe and Co atoms into the Cu. Supersaturated fee solid solutions with crystallite size of -25-30 nm have been prepared by mechanical alloying Cu50Fe25Co25 with and without AI-2O-3 (1%, 3%, 10%) powders. The effect of grain size on magnetic properties was studied. Milling time affects significantly the microstructure, composition and magnetic properties for both systems. The introduction of ceramic alumina influences the recrystalization of the metallic system although the mechanism for nano rystallising the metallic powders through mechanical alloying seems to proceed similarly.