Tungsten carbide (WC) synthesis from novel precursors

This paper deals with the production and properties of tungsten carbide (WC) powders from novel carbon coated precursors. The process has two steps in which the oxide powders were first coated with carbon by cracking of a hydrocarbon gas, propylene (C3H6), secondly mixed with a substantial amount of carbon black, and finally treated at temperatures in the range of 600-1400 degrees C or 2 h in flowing Ar or 10% H-2-Ar atmosphere to synthesize WC. The produced powders were characterized using TEM, BET surface area analyzer, X-ray diffraction and chemical analysis (oxygen and carbon). The results obtained for various types of pre cursors treated in different atmospheres indicated that the coated precursors produced high quality powders. Single phase, submicron WC powders were synthesized at temperatures as low as 1100 degrees C. WC powders produced at 1400 degrees C for 2 h in flowing 10% 6 H-2-Ar gas mixture were submicron (3 5 m(2)/g), single phase, and had low oxygen content (0.20.5 wt%). The sintering tests demonstrated that these powders can be densified to near theoretical density using 20 wt% Co binder at 1500 degrees C for 2 h in flowing 10% H-2-Ar atmosphere. (C) 2000 Elsevier Science Ltd. All rights reserved.