Effects of Y2O3 Content on Properties of Fe-Y2O3 Nanocomposite Powders Synthesized by a Combustion-Based Route
Iron-based metal/ceramic nanocomposite materials have attracted increasing attention owing to their outstanding mechanical,electrical,and magnetic properties with potential applications in many industrial fields.However,several technical routes,such as mechanical alloying,sol-gel,and elec-trodeposition,have limitations,including lengthy synthesis processes,complex experimental equipment,and expensive raw materials.In view of the urgent demand for high-quality iron-based metal/ceramic mag-netic nanocomposites,Fe-Y2O3 nanocomposite powders with different Y2O3 contents(mass fraction)have been prepared using a combustion-based route.The effects of the Y2O3 content on the microstructure,grain size,and magnetic and sintering properties of the nanocomposite powders were examined.The Fe-Y2O3 nanocomposite powders exhibited a connected network structure composed of nanoparticles regard-less of the Y2O3 content,but the grain size decreased gradually with increasing Y2O3 content.The magnet-ic performance test showed that the iron nanopowder without Y2O3 had a saturation magnetic induction and coercivity(Hc)of 1.97 T and 6.4 kA/m,respectively.The saturation magnetic induction of the Fe-Y2O3 nanocomposite powders decreased gradually with increasing Y2O3 content,whereas the Hc increased.The saturation magnetic induction and Hc of the Fe-Y2O3 nanocomposite were 1.45 T and 58.9 kA/m,re-spectively,at a Y2O3 content of 2％.The as-synthesized Fe-Y2O3 nanocomposite powders were densified by pressureless sintering.When the Y2O3 content was low,the nanocomposites could reach a higher rela-tive density at a lower sintering temperature of 700℃.In contrast,densification was difficult to achieve when the Y2O3 content was increased to 1％or 2％even at a high sintering temperature of 1300℃.
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