Paper number 705

SYNTHESIS OF A (WSI2, W5SI3)-SIC COMPOSITE USING THE REACTION BETWEEN WC AND SI

F. J. Narciso-Romero¹, P. Pujalte¹, R. Arpón¹, F. Coloma¹, A. Sepúlveda-Escribano¹, F. Rodríguez-Reinoso¹ and M. Komatsu².

1Dpto. Inorgánica, Universidad de Alicante, Apdo.99, 03080, Alicante, Spain.
2Kyushu National Industrial Research Institute, Shuku, Tosu, Saga 841, Japan.

Summary

This paper reports a study on the formation of tungsten and molybdenum silicides by displacement reaction between Si-WC, and Si-Mo2C respectively at temperatures ranging from 1300°C to 1900°C. The preparation variables have been the ratio metallic carbide to silicon ratio in order to control the type of silicide formed, and the W/Mo ratio, in order to synthesise the mixed silicide. The synthesis of different silicides takes place at different temperatures; however, it is necessary to increase the temperature to 1900°C for the synthesis of W5Si3. The Vickers hardness of the silicides increases with the mixture of both silicides (MSi2, M5Si3), in the mixed silicides (Mo,W)Si2 the best results are obtained, when the (Mo/W) ratio is 3/1. In this case, the value is 16.5 GPa, and the fracture toughness for the same material is 8MPa·m1/2.

Keywords

WSi2, MoSi2, (WSi2, W5Si3)-SiC, (Mo/W) Si2- SiC, WC, Mo2C.