The effect of laser remelting in the formation of tunable nanoporous Mn structures on mild steel substrates

▶ Nanoporous manganese was fabricated by a three-step process involving high power laser cladding of a homogeneous Cu40Mn60 alloy coatings onto a mild steel substrate, laser remelting for tuning the grain size and the composition homogeneity followed by selectively electrochemical de-alloying for removal of Cu element and formation of nanoporous Mn. This paper focuses on the influence of the laser remelting speed on the dentritic arm space and finally the nanoporous structure evolution. The microstructure and homogeneity of the precursor Cu40Mn60 alloys have a significant influence on the evolution of nanopores during selectively electrochemical de-alloying. Nanoporous Mn with nanopore sizes ranging from 80 to 130 nm was fabricated by this method. It is found that smaller nanoporosity leads to significant improvements in surface-enhanced Raman scattering.