Electrophysical Features of Spark-Plasma Sintering of TiN–TiB2 Composite.
I. Effect of the Electrophysical Parameters of Spark-Plasma Sintering on the Structure and Properties of TiN–TiB2 Compo


The electrophysical features of spark-plasma sintering (SPS) of TiH2–BN and Ti + BN powder mixtures to produce ceramic composite material based on TiN + TiB2 are studied and the dependence of its properties on direct-current density at the initial stage of sintering is established. To determine the direct current density, the method for calculating the effective cross-sectional area Seff of “die–sample” subcircuit is proposed. The basic part of electric current passes through the graphite matrix at the initial stage of sintering because of resistances on contacts and presence of α-BN dielectric. The basic part of electric current passes through the sintered sample at the final stage of sintering since TiN + TiB2 composite is synthesized and densified and, consequently, the conductivity of the sintered sample sharply increases. Higher initial direct-current density during sintering of TiHx hydride samples leads to increase in relative density and, respectively, conductivity, microhardness, fracture toughness, and abrasive wear resistance.