Simple femtosecond laser-based production of enlarged nickel surfaces alloyed with molybdenum, iron and cobalt using aqueous solutions and metal foils

An entirely femtosecond laser (fs-laser) based process for the production of stable, enlarged and alloyed nickel surfaces is presented. The process allows the use of metal foils and aqueous salt solutions as alloying element sources. We alloy iron from an aqueous element source as well as molybdenum and cobalt from commercially available foils on nickel mesh surfaces without further coating process. It is shown that the content of alloyed iron on the nickel mesh surface structured with the fs-laser depends on the concentration of the aqueous iron(II) sulfate solution used. The alloy content of cobalt and molybdenum is controlled by adjustable laser parameters. Cross-sections prepared by a focused ion beam and subsequent energy dispersive X-ray spectroscopy shows that molybdenum and nickel form alloyed nanoscale particles on the structured nickel surface. The combination of an aqueous iron(II) sulfate solution and a molybdenum metal foil leads to a ternary nickel-molybdenum-iron surface alloy. The presented fs-laser alloying process can be applied to further metal combinations and offers the potential to create new materials and properties.