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upled treatment of both solutal diffusion and heat transport during solidification. REFERENCES 1. K.A. Jackson and J.D. Hunt: Trans. TMS-AIME, 1966, vol. 236, pp. 1129-42. 2. C. Zener: Trans. TMS-AIME, 1946, vol. 167, pp. 550-95. 3. W.A. Tiller: Liquid Metals and Solidification, ASM, Metals Park, OH, 1958, pp. 276-318. 4. R.M. Jordan and J.D. Hunt: Metall. Trans., 1972, vol. 3, pp. 138590. 5. S.M.D. Borland and R. Elliot: Metall. Trans. A, 1978, vol. 9, pp. 1063-67. 6. R. Elliot: Mater. Sci. Eng., 1984, vol. 65, pp. 85-92. 7. V. Seetharaman and R. Trivedi: Metall. Trans. A, 1988, vol. 19A, pp. 2955-64. 8. B. Wei, D.M. Herlach, B. Feuerbacher, and F. Sommer: Acta Metall. Mater., 1993, vol. 41, pp. 1801-09. 9. P. Magnin and R. Trivedi: Acta Metall. Mater., 1991, vol. 39, pp. 453-67. 10. D.K. Banerjee, G. Upadhya, and D.M. Stefanescu: F. Weinberg Int. Symp. on Solidification Processing, J.E. Lait and I.V. Samarasekera, TMS-CIM, Pergamon Press, Elmsford, NY, 1990, pp. 319-33.

Synthesis of Full-Density Nanocrystalline Tungsten Carbide by Reduction of Tungstic Oxide at Room Temperature M. SHERIF EL-ESKANDARANY, M. OMORI, M. ISHIKURO, T.J. KONNO, K. TAKADA, K. SUMIYAMA, T. HIRAI, and K. SUZUKI Among the hard alloys, WC alloys find wide industrial applications as tips for cutting tools and wear-resistant parts. Their intrinsic resistance to oxidation and corrosion at high temperatures also makes them desirable as a protective coating for devices at elevated temperatures. In the industrial scale of production, WC is prepared by a direct union of the elements at a temperature of 3273 to 3473 K.[1] Accordingly, the high cost of preparation is a disadvantage of this process. Here, we report a novel technique for preparing a large amount of WC powder using a simple method. This process is based on mechanical solid-state reduction (MSSR)[2] followed by solid-state reaction (SSR) during room-temperature ball milling (a high energy ball mill, Fritsch P6, was used at a rotation speed of 4.2 s21) of a mixture of WO3, Mg, and C powders. To avoid the contamination content that might be introduced into the powder

M. SHERIF EL-ESKANDARANY, formerly Lecturer of Materials Science and Metallurgy, Mining and Petroleum Engineering Department, Faculty of Engineering, Al-Azhar University, Nasr City 11884, Cairo, Egypt, is Visiting Professor, Department of Chemical Physics of NonCrystalline Materials, Institute for Materials Research, Tohoku University. T.J. KONNO, Research Associate, K. SUMIYAMA, Associate Professor, and K. SUZUKI, Professor, Department of Chemical Physics of NonCrystalline Materials, M. OMORI, Research Associate and T. HIRAI, Professor, Department of High-Temperature Materials Science, and M. ISHIKURO, Research Associate, and K. TAKADA, Lecturer, Department of Analytical Science, are with Tohoku University, Sendai 980-77, Japan. Manuscript submitted July 22, 1996. METALLURGICAL AND MATERIALS TRANSACTIONS A

Fig. 1—Dependence of the vial temperature on the milling time during ball milling a mixture of WO3, Mg, and C powders.