This research focused on the study of Yttrium Iron Oxide (YFeO) prepared by nanoscale processing, and examining the nanocrystalline phases of these ceramic oxide powders. These powders are precursors for thermal spray coatings. Studying the microstructure of this crystalline oxide and learning its properties allows for a better understanding of how nanocrystalline materials function. Consequently, this analysis will lead to a more accurate and refined processing for this material. This ceramic oxide possesses magnetic properties and is exceptionally efficient as both a transmitter and transducer of acoustic energy, in addition to being utilized in microwave devices. Using x-rays and electron microscopy analysis, the phase identification of the various structures in this system was made possible. After studying the background for electron microscopy characterization, analyzing electron diffraction patterns, and measuring the d-spacings (in Angstroms) and angles between atomic planes, certain aspects of the material's structural detail were revealed, such as its unit cell configuration. The experimental results obtained through microscopic observations were then compared to the published results found in the JCPDS (Joint Committee on Powder Diffraction Standards) database and Pearson's Handbook of Crystallographic Data. Furthermore, the Desktop Microscopist simulation software aided the process of matching experimental data to theoretical calculations by generating visual representations of the material's electron diffraction patterns. The results indicate the existence of more then one phase of the Y-Fe-O system in the samples inspected. The phase Fe16Y6O was present along with the YFeO3 phase. These findings demonstrate the instability of each phase of the structure of nanocrystalline Yttrium Iron Oxide. Thus, supplementary research is needed to map the region of stability for this material.