Tailoring PBF-LB of austenitic stainless steel for potential antifouling applications

Fouling refers to the accumulation of unwanted particles, macromolecules, salts, or biological matter on surfaces. A common example is biofouling, where biofilms form through extracellular substances and microbial cell matrices. Beyond reducing the efficiency of machines and components, fouling can significantly shorten the lifespan of materials by accelerating corrosion. Additive manufacturing (AM) is a collection of novel processes for fabricating tridimensional parts layer by layer. Among AM technologies, powder bed fusion using a laser-based system (PBF-LB) is widely used for processing pure metals and alloys due to its ability to create highly complex geometries. This capability enables the production of components with enhanced efficiency, such as heat exchangers, food mixers, and ship propellers – structures often exposed to biofouling. This study explores the effects of different gas protective atmospheres (Ar and N₂) on the microstructure, thermal properties, surface characteristics, and densification of stainless steel bulk samples fabricated via PBF-LB over a large processing window. When identical processing parameters (layer thickness, laser power, scanning speed, hatch spacing, scan rotation, and scan pattern) were used, variations in energy density due to atmospheric differences influenced thermal properties, grain size distribution, crystallographic orientation, nitrogen content, and surface roughness of bulk parts. These changes suggest that antifouling properties could be enhanced by selecting appropriate processing atmosphere. Antifouling surfaces are critical in industries such as naval, pharmaceutical, and food industries where microbial accumulation can compromise performance and hygiene. The findings of this study present new opportunities for optimizing PBF-LB processing of AISI 316L stainless steel to develop surfaces with improved resistance to fouling.