Innovative preparation and corrosion resistance of Fe-based amorphous coatings fabricated by ultra short pulse laser manufacturing process

Fe-based amorphous coatings are regarded as the new generation of surface protective coating materials for engineering equipment due to their excellent corrosion resistance, wear resistance and other properties. However, the thermal spraying preparation process results in low bonding strength and numerous through pores caused by the layered structure of Fe-based amorphous coatings; The laser cladding process causes severe thermal effects on Fe-based amorphous coatings, resulting in crystallization of the coating and the presence of defects such as cracks and pores. To address these issues, this study utilized the advantages of ultra short pulse laser, namely femtosecond laser powder bed melting (Fs-LPBF) process, which has the advantages of high cooling rate and tight bonding with the substrate, to prepare Fe-based amorphous coatings for the first time. The effects of laser power and scanning speed on the microstructure and corrosion resistance of the coatings were systematically investigated. The research results show that at a laser power of 50 W and a scanning speed of 500 mm/s, the Fe-based coating maintained a relatively high amorphous volume fraction (72.51 vol%), and the coating exhibits a dense structure with nearly defect-free, which has the best corrosion resistance performance. The above research results provide a novel process approach for preparing high-performance Fe-based amorphous coatings, and also offer a new idea for additive manufacturing of Fe-base amorphous bulk materials.