Mechanical properties of Cf/SiC-ZrB2 ceramic composites with bouligand structure prepared by low-temperature demolding combined with precursor infiltration and pyrolysis

A method combining low-temperature demolding with precursor infiltration and pyrolysis (PIP) for preparing C f /SiC-ZrB 2 ceramic composites with bouligand structure is proposed. First, C f /SiC-ZrB 2 -PCS ceramic films were prepared using polycarbosilane (PCS), carbon fiber, and SiC-ZrB 2 ceramic particles through liquid nitrogen demolding technology. Then, C f /SiC-ZrB 2 green body with bouligand structure was achieved by helically assembled and pre-crosslinked C f /SiC-ZrB 2 -PCS ceramic films at a fixed angle. Finally, precursor infiltration and pyrolysis method was employed to densify the C f /SiC-ZrB 2 ceramic composites with bouligand structure using PCS. The mechanical properties of the composites with different carbon fiber contents were investigated, revealing that at a carbon fiber content of 30%, the composites exhibited a flexural strength of 358.9   MPa, a fracture toughness of 10.4   MPa·m 1/2 , and a work of fracture of 2445.4   J·m -2 . The toughening mechanism of C f /SiC-ZrB 2 ceramic composites with bouligand structure was elucidated through two-dimensional crack propagation analysis via scanning electron microscopy (SEM) with three-dimensional fracture network reconstruction using synchrotron X-ray computed tomography (CT).