PRODUCING OF NiFe_2O_4/(METAL, ALLOY) NANOCOMPOSITE/COMPOSITE POWDERS AND COMPACTS BY MECHANICAL MILLING AND SPARK PLASMA SINTERING

摘要

The NiFe_2O_4/(Ni, N_3Fe) nanocomposite powders were produced by mechanical milling. Commercial nickel and nanocrystalline nickel ferrite and Ni_3Fe intermetallic compound powders obtained by mechanical milling/alloying were used. The nanocomposite powders obtained after 15 minutes of milling were compacted by a home-made spark plasma sintering equipment. The sintering process carried out at 600 °C leads to a relatively good density of the obtained compacts, 81.2 % for the composite with Ni and 89.0 % for composite with Ni_3Fe. A sintering temperature of 800 °C leads to the interdiffusion phenomena in the NiFe_2O_4/N_3Fe composite material. This leads to the formation of a wustite phase and change the intermetallic compound and ferrite stoichiometry. The powders and compacts were characterized by means of X-ray diffraction, scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX) and differential scanning calorimetry (DSC).