Structural investigations of diamond composites prepared by the infiltration of the diamond compact near the line of thermodynamic equilibrium of graphite with diamond

The structural order of diamond polycrystalline composite materials obtained by the infiltration of the diamond compact by nickel-silicon alloys at pressures up to 5.0 GPa and temperatures reaching 1800 K is investigated. It is established that they consist of a diamond skeleton and intercrystallite metal-ceramic binder. The diamond skeleton is formed from diamond grains of the starting size with weak diamond-diamond bonds, while the intergrain space is filled by diamond fragments and an intermetallic binder. The formation of carbide layers from silicon carbide on the surface of diamond grains determines the strength properties of diamond composites in general.