ISSN:
1573-4889
Keywords:
Fe-Cr-S system
;
spinel-monoclinic transition
;
Cr3S4
;
FeCr2S4
;
Cr1−xS
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Phase relations and stability fields in the Fe-Cr-S system were investigated at 1073 and 1173 K in the sulfur pressure range 100–10−5 Pa. The sulfides, produced by the sulfidation-annealing process of Fe-Cr alloys followed by rapid quenching, were characterized using X-ray diffraction powder analysis at room temperature. The Cr3S4 in the Cr-S system extends beyond the FeCr2S4 stoichiometry in the Fe-Cr-S ternary system at intermediate sulfur pressures. The spinel-monoclinic transition of the FeCr2S4 was observed at sulfur pressures of 10−3–10−3.5Pa at 1073 K and at 100–10−0.5 Pa at 1173 K. The free energy change for formation of the spinel, FeCr2S4, from a monoclinic (Cr, Fe)3S4−y, hexagonal (Fe, Cr)1−xS, and sulfur vapor is given by the relation ΔG = −1523 + 1.09 T (kJ/mol). The phase-transition mechanism of FeCr2S4 is discussed on the basis of an enhancement of the cation coordination numbers from 4-6-6 for the spinel to 6-6-6 for the monoclinic, when the sulfur partial pressure decreases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00667061
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