Ablation properties of SiC-reinforced PBI resin matrix composites under high-energy continuous laser ablation

Abstract

In this work, poly-p-phenylene benzobisoxazole (PBO) fibers reinforced polybenzimidazole (PBI) resin-based laser ablation composites (thickness = 5 mm) with different SiC contents were prepared. SiC/PBI/PBO composites exhibited good mechanical properties, excellent thermal stability and laser ablation properties. The laser ablation properties and ablation mechanism of the composites were investigated using a high-energy continuous-wave laser (30 MW·m−2). Increasing the SiC content led to increase in composites density, while decreasing the bending performance of the composites. However, it improves the mass and linear ablation rates, resulting in an overall improvement in ablation properties. At a SiC content of 70 %, the composite exhibited a mass loss of 8.2 %, a mass ablation rate of 9.2 mg·s−1, and a linear ablation rate of 0.11 mm·s−1. The ablation process of SiC/PBI/PBO composites was delineated into pre-ablation and post-ablation stages, with the ablated composites divided into the ablation center, transition region, and outer region based on morphological characteristics. After ablation, numerous white hollow SiO2 spheres and SiO2 protective layers were formed in the ablation centers, the transition regions were deformed and cracked, while the outer region remained unscathed.