Internal chloridation of dilute Ni-Cr alloys
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Internal Chloridation of Dilute Ni-Cr Alloys
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Fig. 6--Predominance area diagram of the Co-S-O system at 1113 K.
area diagrams above 1148 K should therefore include a stability zone for the liquid phase. The predominance area diagrams of the Co-S-O system reported by Ingraham ~'2 included only the Co9S8 and CoS2 solids at 950 and 1200 K. The results of the present study indicate the stable sulfide phases at 950 K are Co9S8, CoSl+y, and COS2, whereas those at 1200 K are liquid phase, C0453+y, CoSl+v, and COS2.
One of the authors (N. J.) expresses his gratitude to the LASPAU (The Latin American Scholarship Program of American Universities) for the scholarship which allowed him to carry out this research.
REFERENCES 1. T.R. Ingraham: Can. Met. Quart., 1964, vol. 3, pp. 221-34. 2. T.R. Ingraham: Proceedings of the First International Meeting
on Applications of Fundamental Thermodynamics to Metallurgical Processes, G.R. Fittered, ed., Gordon & Breach Sci. Pub. Inc., New York, NY, 1967, pp. 179-97. 3. M. Hansen and K. Andereko: Constitution of Binary Alloys, 2nd ed., McGraw-Hill Book Co., New York, NY, 1958, pp. 497-99. 4. R.P. Elliott: Constitution of Binary Alloys, Ist Supplement, McGrawHill Book Co., New York, NY, 1965, p. 332. 5. F.A. Shunck: Constitution of Binary Alloys, 2rid Supplement, McGraw-Hill Book Co., New York, NY, 1969, p. 263. 6. Y.A. Chang and R. C. Sharma: Calculation of Phase Diagrams and Thermochemistry of Atloy Phases, Y. A. Chang and J. F. Smith, eds., TMS-AIME, Warrendale, PA, 1979, pp. 145-74. 7. T. Rosenqvist: J. Iron Steel Inst., 1954, vol. 176, pp. 37-57. 8. M. Laffite: Bull. Soc. Chim. France, 1959, pp. 1223-33. 9. T. Leegaard and T. Rosenqvist: Z. Anorg. Chem., 1964, vol. 328, pp. 294-98. 10. H. Rau: J. Phys. Chem. Solids, 1976, vol. 37, pp. 931-34. 11. Y.O. Chen and Y.A. Chang: Metall. Trans. B, 1978, vol. 9B, pp. 61-67. 12. O. Kubaschewski and C. B. Alcock: Metallurgical Thermochemistry, Pergamon Press, New York, NY, 1979, pp. 278-84.
The phenomena and kinetics of the internal oxidation of dilute alloys are well established. ~'2'3 Reddy and Rapp have reported significant solubilities and diffusivities for fluorine in solid copper and nickel at elevated temperatures, 4'5 and have observed the internal fluoridation of a Ni-5.6 at. pct Cr alloy. 6 Likewise, the internal chloridation of a base metal alloy containing a small concentration of a more reactive solute is expected if the base metal exhibits a substantial solubility and diffusivity for elemental chlorine. No prior determinations of solubility or diffusivity data are available for chlorine in any metal. In this study two solid solution Ni-Cr alloys (0.56 and 2.0 at. pct Cr) were internally chloridated by an experiment similar to that of Reddy and Rapp. 6 Small annealed alloy c
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