Phase composition of composite materials produced by high-pressure reaction sintering in the cubic boron nitride—diamond—aluminum system

X-ray diffraction analysis has been used to study the phase composition of composite materials produced by high pressure—high temperature (4.2 GPa, 1750 K) sintering of cBN and Al powders with diamond added to the reaction mixture. It has been shown that as a result of the reaction sintering depending on the relationship among the mixture components, in parallel with cBN and diamond, the composite materials may contain aluminum nitride, diboride, carboboride and carbide as well as solid solutions of boron and/or carbon based on the crystalline lattices of Al, AlN, and cBN. A possibility is shown of dispersion hardening of a composite providing the diamond content is below the threshold percolation. Along with diamond an increase in the resistance to abrasive wear of composites is responsible by the Al₃BC phase, which is located at the phase boundaries.