The effect of heating rate and composition on the properties of spark plasma sintered zirconium diboride based composites

Highlights: ► We investigated the effect of heating rate on spark plasma sintering of ZrB2–SiC–ZrC composites. ► Adding SiC up to 10 wt.% had a positive effect on densification and strength. ► Increasing heating rate promoted densification and retarded grain growth when SiC and ZrC content was above 15 wt.%, respectively. ► Increasing heating rate had a slight negative effect on densification when SiC and ZrC content was at 10%, respectively. - Abstract: Five different compositions of ZrB2–SiC–ZrC were prepared and then processed by spark plasma sintering (SPS) to a maximum temperature of 2000 °C, with heating rates of 100 °C/min and 200 °C/min. Grain size, density, Rockwell hardness, flexural strength, and thermal conductivity were evaluated for the processed composites. Adding SiC up to 10 wt.% had a positive effect on densification and strength. Increasing the heating rate promoted densification and less overall grain growth for samples with SiC and ZrC above 15 wt.% each, and had a slight negative effect on densification when these values were at 10%.