Isothermal section of Nd–Mn–As phase diagram at 800 °C

Abstract

Abstract The isothermal section of the Nd–Mn–As ternary system at 800 °C has been constructed in this work by using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques. This isothermal section consists of 11 single-phase regions, 19 two-phase regions and 9 three-phase regions. The maximum solubility of As in (Mn) is about 2.602 at.% As and that of Mn in Mn3As and NdAs is below 1 at.% Mn. The highest solid solubility of Nd in MnAs is less than 1.25 at.% Nd. The decomposition temperature of NdAs2 → NdAs + As is about 668 °C. The phase Nd3As could be slowly composed by peritectic reaction L + NdAs → Nd3As at higher temperature. The phase Mn3As still exists under this experimental condition. No ternary compound was found to exist in this section at 800 °C.