Kinetics, nanomechanical and tribological characterizations of Fe2B layers on ASTM A29 steel

This work investigates the application of the pack-boronizing process to a low-alloy steel of type ASTM A29 within the temperature range 1123-1273 K. Microscopic observations revealed the formation of a single Fe2B layer at all processing temperatures, with a less pronounced toothed interfacial morphology. The tribological behaviour of the boride layers was studied using pin-on-disc tests, and their nanomechanical properties, such as elastic modulus and nanohardness, were evaluated by nanoindentation tests. Furthermore, the Taylor expansion (TE) model was implemented to assess boron diffusivities in Fe2B, from which the activation energy was determined. The empirical verification of this approach has been made employing four additional boriding conditions.