At high temperature and pressure, diffusion of carbon occurredbetween tantalum and tantalum carbide powders. Depending on theinitial size of the tantalum grains, various ceramic grades wereobtained by sintering Ta and TaC powders. Either an equilibriumcomposition was reached between the fine metal grains and thetantalum Carbide grains, leading to the formation of monolithic butunstoichiometric carbides. On the other hand, under the sameexperimental conditions, ceramic-metal composites were Prepared byusing a coarse Ta grains powder.
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