Tribo-Mechanical Behavior of Films and Modified Layers Produced by Cathodic Cage and Glow Discharge Plasma Nitriding Techniques

Two surface modification techniques, the glow discharge plasma nitriding (GDPN) and cathodic cage (CCPN), were compared regarding mechanical tribological behavior of layers produced on AISI 316 stainless-steel surfaces. The analyses carried out at micro/nanoscale using nanoindentation nanoscratch tests. temperature (°C) time (h) parameters 350/6, 400/6, 450/6. Morphology, structure, microstructure evaluated by X-ray diffraction, scanning electron optical interferometry microscopies, energy-dispersive spectroscopy. GDPN results in stratified modified surfaces, solidly integrated with substrate, a temperature-dependent composition comprising nitrides (γ’-Fe4N, ε-Fe2+xN, CrN) N-solid solution (γN phase). latter prevails for low treatment temperatures. Hardness increases from ~2.5 GPa (bare surface) to ~15.5 (450 °C). scratch resistance GDPN-modified surfaces presents strong correlation layer thickness, result that 400 °C condition exhibits highest standards against microwear. In contrast, CCPN well-defined dual-layers any A top 0.3–0.8 µm-thick nitride film (most ε-phase), brittle easily removable under loads as 63 mN, covers γN-rich case hardness 10 GPa. thickness underneath 450 is similar (3 µm); other hand, average roughness much lower, comparable reference (Ra ~10 nm), while formation involves no chromium depletion. Moreover, edge effects are absent across entire sample´s surface. conclusion, among studied conditions, disclosed best tribo-mechanical performance, whereas resulted superior finishing application purposes.