Effect of Sintering Parameters on the Densification of ZrB۲-SiC based Composite

In this study, ZrB۲-SiC ultra-high temperature ceramic composite was sintered using Spark Plasma Sintering (SPS) process with WC/HfB۲ modifiers at different sintering temperatures of ۱۸۵۰, ۱۹۰۰, ۲۰۰۰, and ۲۰۵۰˚C for ۸ and ۲۵ 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 ZrB۲-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 ZrB۲-SiC-based composite with a relative density of ۹۰% was obtained at ۲۰۵۰˚C under ۳۰ MPa for a ۲۵-minute soaking time. The densification curve of this sample showed a typical “S” shape. The best water absorption and apparent porosity values obtained as ۱.۳ and ۶.۷%, respectively. The minimum and maximum punch displacement of the samples was ۲.۲ and ۳.۶ mm, respectively. Use of WC/HfB۲ modifiers led to the formation of byproducts of WB and HfB.

کلیدواژه ها:

ZrB۲ ، Densification ، Spark Plasma Sintering ، porosity ، Density