Fabrication and functional characteristics of micro/nano structures on the RB-SiC surface through nanosecond pulsed laser irradiation

Reaction-bonded silicon carbide (RB-SiC) is gaining increasing attention due to its exceptional mechanical properties contributed by the dispersion of hard silicon carbide (SiC) and silicon (Si), which has been extensively applied in aerospace and automobile industries. Fabrication of micro/nano structures on the RB-SiC surface can endow it some specific functional properties, but conventional manufacturing procedures face challenges due to the intrinsic hard-brittle nature of RB-SiC. In the present study, various micro/nano structures, including dome-like particle structures, micro-cone structures and the spider web-like film, are fabricated on the RB-SiC surface by nanosecond pulsed laser irradiation under different experimental conditions. Comparative experiments are performed to explore the effects of laser power and scanning speed on the microscopic morphology and chemical composition. Consequently, the ablation mechanism is clarified. The formation of micro-cone structures covered by the spider web-like film can result in a wettability transition of the RB-SiC surface from hydrophilicity to superhydrophilicity. In addition, by introducing the spider web-like film, the reflectivity of the RB-SiC surface is increased by an impressive 83% or more in the wavelength range of 200 to 2500 nm. This study provides a method for improving the surface properties of RB-SiC substrates using a laser-based approach, which is anticipated to expand their application prospects as functional materials.