Metal carbides and derived composites made by milling to obtain a particular nanostructural composite powder

摘要

Metal carbides may be formed by mixing metal powder with a stoichiometric amount of graphite, compressing the same in a mould/die and then sintering. High temperatures (and maybe a bonding agent) are required to effect the final step and finished product. These disadvantages are overcome by exploiting dry high energy milling to bring the starting materials into a very finely divided and reactive state, with regions of metal, carbon and metal based solid solution ranging from 3 to 100 nanometers in diameter. As an alternative source of carbon, cationic organic surfactants may be used instead of graphite in the appropriate proportion. Compacting the milled mixture, followed by sintering at lower temperatures by a margin of at least 400° C., will produce very strong dense carbides at low cost. The method may be extended to include metal based composites, which also includes cermets, by incorporating an appropriate excess of metal powder(s) in the starting materials. The carbides and their metal based composites have applications in the field of abrasives, cutting tips for lathe tools, masonry drills and master alloys for steels.