Spark plasma sintering of TiyNb1−yCxN1−x monolithic ceramics obtained by mechanically induced self-sustaining reaction

Nanometer-sized titanium-niobium carbonitride powders (TiyNb1−yCxN1−x) with different Ti/Nb atomic ratios were obtained by a mechanically induced self-sustaining reaction, and sintered by spark plasma sintering technique at 1500 °C for 1 min in a vacuum atmosphere. Mechanical properties such as hardness and Young's modulus were determined by nanoindentation technique and friction and wear coefficients assessed by ball-on-disk testing using alumina ball in dry sliding conditions. The fracture surface and wear tracks of samples were examined by scanning electron microscopy. Results showed that it is possible to obtain dense monolithic ceramics from the solid solution (TiyNb1−yCxN1−x) with good mechanical properties and excellent wear resistance. The optimum values of nanomechanical properties were found for the Ti0.3Nb0.7C0.5N0.5 ceramic composition, which exhibited a high hardness over 26.0 GPa and Young's modulus around 400 GPa.