INTERFACE STRUCTURE IN SINTERED FE-Y2O3 POWDER STUDIED BY HIGH-RESOLUTION ELECTRON-MICROSCOPY

A yttria dispersed iron alloy with the composition of 2 mol%Y2O3 have very strong tensile strength of 350 MPa. The interface structure of the iron-yttria in the materials was investigated by X-ray diffraction and electron prove microanalysis (EPMA). However, the observation shows no chemical reaction layers of yttria and iron formed in the boundary region. The microstructures of the interfaces in the (001)Y2O3/(001)Fe, (111)Y2O3/(111)Fe and (152)Y2O3/(111)Fe planes were means of the high-resolution electron microscope (HREM). In the cases of (001)Y2O3/(001)Fe and (111)Y2O3/(111)Fe planes, these were formed lattice images of about 10 nm layers at the interfaces. These now spots of the optical diffraction correspond to these lattice images show 0.35 nm and 0.29 nm, respectively. These images of the interlayer estimate chemical reaction layer. The reaction layer is contributed to relaxation at the boundary of Y2O3 and Fe. The narrow reaction layer causes the strong tensile strength of this material.