Phase diagram of Fe/sub x/V/sub 1-x/O2 in the 0 less than or equal to x less than or equal to 0.25 region

The phase diagram of the Fe/sub x/V/sub 1-x/O2 system (0 less than or equal to x less than or equal to 0.25) has been studied in detail by means of x-ray diffraction and differential scanning calorimetry (DSC). As the result, there appear successively six phases, M1 → T → M2 → M4 → O → X (the same notation as the Cr/sub x/V/sub 1-x/O2 system. O; orthorhombic, X; unknown) with increasing x. Change of the phase transformation temperature Tt and the heat of transformation ΔH with the impurity concentration x have been determined