Preparation and mechanical performance of SiCf/SiC minicomposites with HfSiO4 interphase

SiC fiber bundles with 1–4 HfSiO₄ sub-layers as the interface coating were successfully obtained with detailed optimized preparation parameters via the non-hydrolyzed sol-gel (NHSG) and dip-coating method. Subsequently, SiC_f/SiC minicomposites reinforced with HfSiO₄-coated fibers were fabricated through a precursor infiltration pyrolysis (PIP) process. The tensile behavior and microstructures of the prepared SiC_f/SiC minicomposites treated at room temperature, 800 ℃, and 1000 ℃ in an air atmosphere were investigated. The toughening mechanism of the HfSiO₄ interphase in the SiC_f/SiC minicomposites and the corresponding anti-oxidant properties were also thoroughly discussed. Results indicate that SiC_f/SiC minicomposites with the HfSiO₄ interphase possessed a nearly pseudo-plastic fracture characteristic and significantly enhanced anti-oxidant properties. It is inspired that the properties of the SiC_f/SiC minicomposites could be adjusted by controlling the thickness of the HfSiO₄ interphase to acquire desirable properties such as a higher tensile strength or better oxidation resistance.