Enhanced Surface Engineering of Enb Alloy Coatings: Tribo-Mechanical Insights Into Heat Treatment and Sodium Borohydride Levels

The optimization of coating parameters was the main focus of earlier research on electroless Ni-B (ENB) coatings; nevertheless, little is known about how bath composition and heat treatment temperature affect nanoindentation characteristics such scratch hardness, elastic modulus, and nanohardness. EN8 steel specimens with different concentrations of sodium borohydride (NaBH4) are coated with ENB and heated at (355, 455 and 555) °C in order to examine these aspects. The results show that a higher boron content and larger nodules, raising the concentration of NaBH4, improve nanohardness and elastic modulus. Due to the production of boride phases, which contribute to a more compact shape, these qualities are further enhanced with heat treatment. Additionally, scratch hardness rises with the concentration of NaBH4, peaking at 455 °C, where the hard Ni2B phase is most noticeable. Due to their homogenous and compact structure, the coatings show better resistance to wear and friction, even when their surface roughness decreases after being heated.