Significance of hot pressing parameters and reinforcement size on densification behavior of ZrB₂-25 vol% SiC UHTCs

ZrB₂-25 vol% SiC ceramic composites were prepared by hot pressing in order to investigate the effects of processing parameters and SiC particle size (20 nm, 200 nm and 5 μm) on the densification behavior. At this study, an experimental design technique (Taguchi method) was used to specify the significance of four factors and to obtain the optimal conditions. The statistical analysis distinguished the applied pressure as the most effective parameter on the relative density of ZrB₂-SiC composites. A relative density of ~100% was obtained at the optimal processing conditions: temperature of 1850 °C, holding time of 90 min, pressure of 16 MPa and SiC particle size of 200 nm. The confirmation test, performed under optimum conditions, indicated that the experimental outcomes were equal with the expected values from the Taguchi prediction. The mechanisms of enhanced densification of hot pressed ZrB₂-SiC ceramic composites were discussed.