An experimental investigation of the Fe-Ni-Sb ternary phase diagram

Abstract

The ternary system Fe-Ni-Sb has been investigated in the region between 42 and 100 at. % Sb using conventional methods including DTA, X-ray techniques, metallography, and electron probe mi-croanalysis (EPMA). A continuous solid solution was found to exist between the NiAs(B8)-type phases Fe 1+x Sb and Ni 1±x Sb, whereas the marcasite-type phase Fe x Ni 1-xS b 2 is only stable in the ranges 0.50 ≤x≤ 1.00 and 0.00 ≤x ≤ 0.03, respectively. A skutterudite-type compound FeNiSb 6 —isotypic with CoSb 3 —was found to decompose peritectically at 642 ‡C. An isothermal sec-tion of the phase diagram was studied at 600 ‡C by X-ray powder diffraction using the Guinier tech-nique, and the lattice parameters of Fe x Ni 1-x Sb 2 and (Fe y Ni 1-y ) 1±x Sb were determined as a function of composition. Several samples were investigated by microprobe analysis to fix the phase bounda-ries of the (Fe y Ni 1-y Sb-phase. Four invariant ternary reactions were found in the Sb-rich part of the phase diagram, all of them within the narrow temperature range between 615 and 642 ‡C. The results of the DTA measure-ments were also used to construct the liquidus surface in the entire composition range investigated. All experimental information was combined with literature data to yield a complete ternary phase diagram in the composition range between 42 and 100 at. % Sb.