Effect of Sintering Parameters on the Densification of ZrB2-SiC based Composite

In this study, ZrB2-SiC ultra-high temperature ceramic composite was sintered using Spark Plasma Sintering (SPS) process with WC/HfB2 modifiers at different sintering temperatures of 1850, 1900, 2000, and 2050˚C for 8 and 25 minutes. The densification behavior of the composite was also examined using punch displacement-time and temperature-time measurement graphs during SPS. Phase and microstructure evaluations were also done based on XRD, EDS, and FESEM methods. The effect of SPS parameters on the densification of ZrB2-SiC-based composite was studied. In this case, there was no displacement until the pressure was applied due to the low sinterability of boride powders. A ZrB2-SiC-based composite with a relative density of 90% was obtained at 2050˚C under 30 MPa for a 25-minute soaking time. The densification curve of this sample showed a typical “S” shape. The best water absorption and apparent porosity values obtained as 1.3 and 6.7%, respectively. The minimum and maximum punch displacement of the samples was 2.2 and 3.6 mm, respectively. Use of WC/HfB2 modifiers led to the formation of byproducts of WB and HfB.