600 degrees C section of the Fe-FeS-NiS-Ni phase diagram

The 600 degreesC section of the Fe-FeS-NiS-Ni phase diagram was studied by optical and electron microscopy techniques, x-ray diffraction, and electron probe x-ray microanalysis. The results agree with tile most reliable data available in the literature. The solid-solution regions identified are thos e of (FezNi1-z)(3 +/- delta)S-2 (high-temperature heazlewoodite structure), (FezNi1-z)S1+delta, (FezNi1-z)(9+delta)S-8 (pentlandite structure), alpha- (Fe,Ni), and gamma-(Fe,Ni). The section also contains seven two-phase and t hree three-phase regions. The S content of the monosulfide solid solution a ttains 50.8 at. % at Ni : (Ni + Fe) = 0.6 and 54.0 at. % at Ni : (Ni + Fe) = 0.2. The heazlewoodite solid solution contains up to 26 at. % Fe (at 44.3 at. % S). The highest Ni content of the pentlandite solid solution is 22.5 at. % at 47.5 at. % S and 32.0 at. % at 46.2 at. % S.