Cobalt-bound tungsten carbide metal matrix composites and cutting tools formed therefrom
AssigneeThe Dow Chemical Company
InventorsEd E. Timm, Douglas B. Schwarz
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Abstract
Cobalt-bound tungsten carbide metal matrix composites having a unique microstructure are produced by consolidating partially sintered greenware under high pressures, e.g., 120,000 psi, at temperatures less than those used for conventional liquid phase sintering in a relatively short time, e.g., from less than one minute to less than about one hour. The composites have a binder phase which contains less than about 80 weight percent of the tungsten found in a composite prepared from the same or similar compositions via liquid phase sintering. These composites provide cutting tools with both toughness and wear resistance which exceed that of cutting tools made from the same or similar compositions via liquid phase sintering.
Claims12
A substantially fully dense article of manufacture suitable for use in cutting tool applications, said article being formed from a powdered composition comprising tungsten carbide in an amount of from about 82 to about 99 percent by weight of composition and cobalt in an amount of from about 1 to about 18 percent by weight of composition and having a unique microstructure, the microstructure comprising tungsten carbide grains having a mean grain size of less than about five microns, and a binder phase, the binder phase being substantially free of graphite and complex, intermetallic carbides and comprising, tungsten, cobalt and carbon, the tungsten in the binder phase being present in an amount of less than about eighty percent of that present in the binder of an article prepared by liquid phase sintering the same powdered composition at a temperature sufficient to provide substantially complete densification in the absence of external pressure.
Dependencies are inferred from the claim text.