Laser ablation behaviors of C/SiC composites in air

Ablation behaviors of silicon carbide (SiC) coated 2D carbon fiber reinforced silicon carbide matrix (designated as 2D C/SiC) composites prepared by chemical vapor infiltration (CVI) were investigated by a continuous wave CO₂ laser. The 2D C/SiC specimens were exposed under laser for 0.5 s in ambient air, and the laser powers varied from 500 W to 1500 W. A 3D finite element model was established to calculate the temperature distribution in the laser ablation process. The ablation depth, width and profile were measured by Laser Confocal Microscope (LCM). The results indicate that the increase of ablation depth follows a linear relation with the increase of laser power, and the increase of ablation width follows a similar trend with the increase of the isotherm diameter of 1712 ℃. The ablated surface can be distinguished into three different regions by scanning electron microscope (SEM) observation, including ablation center, transition zone and ablation fringe. The ablation behaviors of carbon fibers and SiC matrices in different regions were presented and discussed in the study.