Thermal and Structural Characterization of Nanocomposite Iron Nitride - Alumina and Iron Nitride - Silica Particles

摘要

Nanocomposite iron nitride based powders are known to have enhanced magnetic and other physical properties. To further explore their potential for application in various fields, we have performed a systematic study of the iron nitride - alumina and iron nitride - silica systems. Iron nitride powder of composition Fe_xN (2 < x < 4), containing both Fe_3N and Fe_4N phases, was mechanically milled with Al_2O_3 or SiO_2 powder for 4, 8, 16, 32, and 64 hours at the following compositions; (Fe_xN)_(0.2)(Al_2O_3)_(0.8), (Fe_xN)_(0.6)(Al_2O_3)_(0.4), (Fe_xN)_(0.2)(SiO_2)_(0.8), and (Fe_xN)_(0.6)(SiO_2)_(0.4). Differential thermal analysis and X-ray diffraction were performed to investigate thermal and structural transitions as a function of milling time. As the milling time is increased, the thermal peak corresponding to Fe_4N is diminished, while the one corresponding to Fe_3N is enhanced. These transitions are correlated with X-ray diffraction patterns. All XRD peaks broaden as a function of milling time, corresponding to smaller particle size. Transmission electron microscopy also reveals a decrease in particle size as the milling time in increased.