PREPARATION AND NEUTRONIC STUDIES OF TUNGSTEN CARBIDE COMPOSITE

Abstract

Because of their desirable structural properties, WC, WC+B4C, and WC + TiC are possible materials for use in plasma-facing components of fusion reactors like tokamaks. In this work, seven different compositions of WC-W2C composites have been prepared (30 to 50 at. % C) by an arc plasma melting technique followed by furnace cooling. Efforts have been made to produce a composite that is very hard and tough and that has a high neutron absorbing capacity by adding B4C and TiC (5 to 15 wt% each) to the starting WC powder. Microstructures of the composites were studied by field emission scanning electron microscopy and transmission electron microscopy. Multiphasic structures of the composites exhibited an absence of pores. The WC + TiC and WC + B4C composites showed improvements in microhardness over pure WC. Typical samples of WC-W2C, WC + B4C, and WC + TiC have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller techniques for analysis and correlation of material properties. When irradiated with 14-MeV D-T neutrons, it was observed that the pure WC melt-cast product exhibited a linear neutron absorption coefficient of 0.172 cm(-1). The absorption coefficient was found to be a maximum (0.255 cm(-1)) for 5 wt% B4C added to WC as against Type 316LN stainless steel, which showed a value of 0.078 cm(-1).