Influence of Surface Roughness and Temperature on Niobium Cathodic Cage Duplex Treatment Applied to VP20TS Steel

The use of VP20TS steel is widespread in industry, and continuous efforts to enhance the performance of this steel, coating deposition using the cathodic cage technique has emerged as an effective approach to improve surface properties. This study aims to analyze the modifications induced by the deposition of NbN coatings on VP20TS steel using the cathodic cage technique. A duplex treatment was applied to samples previously subjected to sanding with 800 and 1500 grit SiC paper. The treatments were carried out at temperatures of 350°C, 400°C, and 450°C. The samples were characterized by X‐ray diffraction, optical and scanning electron microscopy, roughness, microhardness, adhesion testing, and microwear analysis. Sanding the surfaces with coarser grit did not produce the expected mechanical anchoring or the consequent improvement in tribomechanical performance. The most significant results include the formation of nitride layers (NbN) in the samples subjected to treatment at 350°C and 450°C, as well as an increase in microhardness (approximately 150%). These conditions also led to the formation of a more uniform surface layer with a maximum thickness of 8.86 µm and an approximately tenfold reduction in wear volume for the sample treated at 400°C.