CARBURING PROCESS FOR PRODUCING TUNGSTEN CARBIDE-COBALT POWDER WITH GRANE SIZES IN THE NANOMETER RANGE.

摘要

A new carbothermic reaction process is described for the thermochemical processing of nanophase WC-Co powders. The process permits shorter reaction times, reduced temperatures, and finer microstructures compared to conventional processing methods. The process builds on our experience with spray conversion processing [1], but involves 1) chemical vapor infiltration reaction of the carbon infiltrant and particle substrate to form WC-Co; and 2) removal of any excess (unreacted) carbon by controlled gasification. A feature of the carbothermic reaction process is its adaptability to conventional WC-Co processing technology, as well as to spray conversion processing technology. The resulting powder particles consist of a network of fine grains, (less than 100 nm) of WC and Co with interconnected fine porosity. Powder particles suitable for subsequent handling and consolidation are readily produced with diameters greater than 10 microns.