Alloy oxide equilibrium in the $Cr-Mn-O$ system

The phase boundaries of the $Cr-Mn-0$ system have been investigated by alloyoxide equllibria at 1173 and 1273 K and by isopiestic technique at 1323 K. The oxide phases which coexist in equilibrium with the $Cr-Mn$ alloys are determined by x-ray diffraction siltdies. The results of the experiments indicate the presence of MnO in equilibrium with Mn-rich alloy whereas $MnCr_20_4$ and $Cr_2O_3$, phases coexist with almost pure Cr. A three-phase equilibrium consisting of $MnCr_2O_4$, and MnO phases has been detected at the alloy composition $X_{mn}=0.252$ at 1323 K. The composition of the alloy delineates the phase boundaries in the isothermal sections of the system. The results are interpreted by thermodynamic analysis of the $Cr-Mn-0$ system using the data from the isopiestic measurements and those available in the literature