Synthesis and magnetic properties of copper and Ba-ferrite ferromagnetic composites by mechanical alloying

Synthesis of ferromagnetic composite materials for the Cu-BaFe12O19 system by mechanical alloying (MA) has been investigated at room temperature. A mixture of copper and barium ferrite with a weight ratio of Cu : BaFe12O19 = 4 : 1, 3 : 2, 2 : 3 and 1 : 4 was used. It is found that Cu-BaFe12O19 composite powders in which BaFe12O19 is dispersed in copper matrix are successfully produced by mechanical alloying of BaFe12O19 with Cu for 80 min. in all composition. The change in X-ray diffraction patterns and magnetic properties reflects the details for the formation of ferromagnetic metal matrix composite of pure Cu and BaFe12O19 during mechanical alloying. Magnetization of Cu-BaFe12O19 composite powders gradually increases with increasing the amounts of barium ferrite, whereas coercive force of MA powders gradually decreases due to the refinement of barium ferrite powders with ball milling. However, it can be seen that the coercivity of Cu-BaFe12O19 MA composite powders with a weight ratio of Cu : BaFe12O19 = 4 : 1 and 3 : 2 ball-milled for 80 min. is still high value of 1400 Oe and 1450 Oe, respectively suggesting that the refinement of barium ferrite powders during ball milling process tend to be suppressed due to the ductile copper.