Isothermal section at 950 °C of the U–Fe–B ternary system

A systematic investigation of the isothermal section at 950 °C of the U–Fe–B ternary system was done by means of X-ray powder diffraction, scanning electron microscopy, complemented by energy dispersive X-ray spectroscopy, and electron-probe microanalysis. At this temperature the phase diagram is characterized by the formation of four ternary compounds with negligible homogeneity regions. The compounds are: UFeB4 (orthorhombic YCrB4-type structure, a = 5.887(1) Å, b = 11.412(2) Å and c = 3.4355(4) Å), UFe3B2 (hexagonal CeCo3B2-type structure, a = 5.049(1) Å and c = 2.9996(7) Å), ∼UFe4B (structure closely related with the CeCo4B-type, and a small hexagonal cell a = 4.932(1) Å and c = 7.037(2) Å), and U2Fe21B6 (Cr23C6-type structure, a = 10.766(4) Å).