Densification, mechanical and tribological properties of ZrB2 by SPS: Effect of pulsed current

• ZrB2, for the first time, was spark plasma sintered varying methodically the DC pulse on-off patterns.
• The effect DC pulse on-off patterns on sintering, densification, mechanical and tribological properties were studied in details.
• The ZrB2 sample at ton = 50 ms and toff = 5 ms pulse conditions showed outstanding structural properties.

The influence of direct current pulse on–off patterns on spark plasma sintering of ZrB2 on densification, mechanical and tribological properties has been investigated systematically. The experimental data showed that the maximum relative density (98.65%) is achieved at 50 ms pulse on (ton) and 5 ms pulse off (toff) time conditions. The maximal Vickers hardness, fracture toughness (DCM) at 1 kgf load, wear volume and wear rate at 10 N load of the ZrB2 sample (ton = 50 ms and toff = 5 ms pulse conditions) were 16.64 GPa, 4.69 MPa√m, 4.05 × 104 μm3 and 1.01 × 10− 3 mm3/N·m, respectively. The electric current delivered during SPS processes in different ‘on–off’ pulse patterns plays a vital role in consolidation and desired structural properties.