Design and optimization of the coating thickness on chopped carbon fibers and sintering temperature for ZrB ₂ -SiC-C _f composites prepared by hot pressing

Interface designation and low-temperature densifying were expected to inhibit the performance attenuation of fiber in the preparation of ceramic matrix composites. Nevertheless, the optimization of interface thickness and sintering temperature were still rarely investigated systematically. Herein, the performance of carbon fiber varied with coating thickness and the heat-treat temperatures were investigated by quantitatively. The tensile strength of carbon fibers degraded dramatically (≥30%) when coating thickness above a critical value. A larger dimension and ordered graphite crystallite structure resulted in the severe performance deterioration of carbon fibers as the sintering temperature exceeding 1500 ℃. The PyC coatings with an appropriate thickness acted as a critical role of changing the fracture mode of the ZrB ₂ -SiC-C _f and noticeably increased the fracture strain of the composite. The regular trend provided a general design strategy in construction of ZrB ₂ -SiC-C _f composite with optimal properties and could be extended to other ceramic matrix composites.