Nuevas tecnologías de tratamiento dúplex para la mejora de la adherencia de recubrimientos DLC sobre acero inoxidable austenítico

Abstract

AISI 316L austenitic stainless steel has become pivotal in both industrial and biomedical applications due to its outstanding corrosion resistance and durability in harsh environments. The composition of this steel, which comprises chromium, nickel, and molybdenum, provides exceptional chemical stability and toughness, making it the leading choice for challenging scenarios. Innovative techniques have been investigated to further improve the capabilities of DLC coating on a versatile material. Among them, the high-power pulsed magnetron sputtering (HiPIMS) method, utilizing positive pulses on AISI 316L austenitic stainless steel, has shown great potential in enhancing the surface properties of the material. Positive pulse HiPIMS coatings provide significant benefits over traditional methods, particularly in their capacity to produce thin layers with high ionic current density and greater impact energy. Consequently, these coatings exhibit enhanced adhesion and a dense coating structure, yielding superior mechanical and tribological properties. To optimize stainless steels wear resistance and properties, the plasma immersion ion implantation (PIII) technique has been adopted. This approach facilitates the development of gradients of hardness on the surface of the substrate, thereby enhancing the material's resistance against abrasive forces and culminating in prolonged durability under frictional conditions. The utilization of shielded plasma nitriding (ASPN) results in substantial enhancement of the DLC coating's adhesion. This method enables the creation of a nitrided layer at the interface between the coating and substrate, which enhances their bond and offers extra protection against early separation. Including substrates produced by additive manufacturing techniques introduces a fresh approach to enhancing the properties of stainless steel. Despite a slight decrease in certain properties when compared to previous treatments, the implementation of duplex treatments with shielded plasma nitriding has been found to be particularly advantageous in this specific context. Ultimately, the primary contribution made by this thesis around duplex treatments focuses on the utilization of DLC WC:C coating techniques via positive pulse HiPIMS, and the introduction of hardness gradients through PIII and ASPN processes. The study conducted the techniques on substrates made via additive manufacturing technologies. Its aim was to enhance the mechanical and tribological characteristics of DLC coatings, thereby significantly improving the surface properties of AISI 316L austenitic stainless steel. This approach strengthens the adhesion of the coatings and offers new perspectives for industrial and biomedical applications.