Laser ablation behavior of SiHfC-based ceramics prepared from a single-source precursor: Effects of Hf-incorporation into SiC

Abstract

Laser ablation test of SiHfC-based ceramic nanocomposites as well as ceramic matrix composites (CMCs) was conducted by exposure to a CO2 laser beam in air. Laser ablation behavior and possible degradation mechanisms of dense monolithic HfC/SiC ceramic nanocomposites as well as of Cf/SiHfC CMCs were investigated. Dense SiC monoliths and Cf/SiC CMCs were exposed to same laser ablation conditions and considered as reference materials. The evolution of microstructure and chemical/phase composition of the studied ceramics was addressed by scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDX) as well as by X-ray diffraction. The results reveal that from the center to the edge of the damaged region of the materials three sections with different surface morphologies and ablation mechanisms are identified. The comparation between the SiC-based monoliths and CMCs with and without Hf demonstrates the positive effects of Hf-incorporation on their laser ablation resistance.