Fabrication and Ablation Behavior of a Novel ۳D Orthogonal Woven C/C-SiC-HfC Composite by I-CVI, SI, and LSI Combined Process

A C/C-SiC-HfC composite was fabricated using a three-dimensional orthogonally woven (۳DW) preform, and the effect of HfC ultra-high temperature ceramic (UHTC) particles on the microstructure and ablation properties of the composite was evaluated. First, pyrolytic carbon (PyC) was infiltrated into the ۳DW preform by the I-CVI method. Then, impregnation of a suspension composed of HfC particles and phenolic resin into the ۳DW preform. Next, liquid Si alloy was infiltrated into the C/C-HfC porous structure at ۱۶۵۰ °C to form a C/C composite with a SiC-HfC matrix. HfC particles and the continuous SiC phase among carbon fibers were saturated and during the oxyacetylene test, covered the surface of the C/C-SiC-HfC composite as a dense continuous SiO۲-HfO۲ layer. This layer acted as a barrier against the diffusion of oxygen into the bulk parts of the C/C-SiC-HfC composite. The results of the oxyacetylene flame test at ۲۵۰۰ °C for ۱۲۰ s showed that the mass and linear ablation rates of the C/C-SiC composite were ۴.۸ mg/s and ۳.۷۵ µm/s, respectively. After the addition of HfC and the formation of the C/C-SiC-HfC composite, these rates decreased to ۱.۶ mg/s and ۰.۹۸ µm/s, respectively.

کلیدواژه ها:

Three-dimensional orthogonally woven (۳DW) ، liquid silicon infiltration (LSI) ، C/C-SiC-HfC composite ، ablation behavior