Laser wobbling surface texturing of AISI 301LN steel for enhancement of the corrosion resistance at high temperature

Abstract

Laser surface texturing (LST) has emerged as a powerful technique for creating surface patterns on various materials, including metals, polymers, and ceramics. Among LST methods, laser wobbling surface texturing (LWST) offers distinct advantages over traditional surface modification techniques. It provides a precise and non-contact approach to customize surface properties without affecting the bulk material. This study investigates the effects of amplitude and frequency of LWST as a surface modification strategy to mitigate high-temperature corrosion in AISI 301LN stainless steel, representing the first investigation of its kind. The study extensively examines the impact of LWST on surface morphology, wettability, phase transformation, and microhardness of 301LN stainless steel. The results reveal that the wobbling frequency of LWST has a greater effect on the surface roughness than the wobbling amplitude. Higher surface roughness of LWST promotes the increase of the surface area and altered surface energy, resulting in an increased wetting behavior. X-ray diffraction analysis confirms a moderate phase transformation from austenite to martensite in the laser-treated samples, which increases the surface hardness compared to the non-treated material. Finally, the corrosion tests conducted in molten carbonate salt at 600 °C evidence a reduction of the corrosion rate around 20 %. LWST promotes the formation of denser oxide layer, improving its effectiveness as a protective barrier against further oxidation.