Fabrication of ZrN-hBN composite ceramics by pulse current pressure sintering and their tribological behavior

The present study deals with the fabrication of the zirconium nitride (ZrN) composite with a dispersion of hexagonal boron nitride (h-BN) and with the tribological behavior thereof. Mixture powders were milled for 180 ks or less by a planetary ball mill. The pulse current pressure sintering (PCPS) method was employed in order to consolidate the mixed powders. The sintered compact of ZrN-5 mass% h-BN powders milled for 180 ks shows high density consolidation having a relative density of 92%. Sliding friction tests between sintered compacts of composite ceramics and SUJ-2 steel ball were performed using a ball-on-disc apparatus, in order to estimate the tribological characteristics of sintered compacts by the friction coefficient evolution. Only a 5% addition of h-BN into the ZrN matrix showed a marked decrease in the friction coefficient to about 0.2, preventing adhesive wear. The sintered compact of ZrN-5 mass% h-BN powders milled for 180 ks maintained low friction coefficient for two-times longer compared to the sintered compared of ZrN-5 mass% h-BN mixed powders. However, finger dispersion of h-BN particle under the range of nanometer size is essential to sustain the self-lubricant effect for longer time to be practical.