Avaliação do efeito de modificações superficiais a plasma no desempenho do aço AISI 316 frente ao desgaste e corrosão

Abstract

In order to improve the sliding wear, cavitation erosion and corrosion resistance of AISI 316 stainless steel, two surface treatments have been realized: Thermochemical plasma diffusion and PAPVD film deposition (Plasma Assisted Physical Vapor Deposition). Five systems have been studied: Substrate (AISI 316 stainless steel), carburizing system (AISI 316 plasma carburizing during 4 hours at 475 ºC) sequential system (AISI 316 plasma carburizing during 2 hours at 475 ºC and plasma nitriding during 2 hours at 450 ºC), carburizing duplex system (AISI 316 plasma carburizing during 4 hours at 475 ºC and (Cr,Al)N deposition (2,5 m)) and sequential duplex system (AISI 316 plasma carburizing during 2 hours at 475 ºC, plasma nitriding during 2 hours at 450 ºC and (Cr,Al)N deposition (2,5 m)). The systems have been characterized by: SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy), GDOES (Glow Discharge Optical Emission Spectroscopy), XRD (X-Ray Diffraction), profile 3D, Rockwell C adhesion test, microhardness Vickers and Knoop and instrumented indentation. The performance tests havebeen realized: Dry sliding wear in configuration pin on disc, vibratory cavitation erosion and anodic polarization. The sliding wear results have shown the best performance of the duplex systems. The carburizing system has shown better performance than sequential system. All systems have been more resistant than AISI 316 stainless steel.The erosion cavitation results have shown excellent performance of the duplex systems due to incubation period increase. The plasma treatments also have shown better performance than AISI 316 stainless steel. The corrosion resistance in NaCl and H2SO4 environment of the plasma treated systems and duplex systems have been greater than AISI 316 stainless steel. Therefore, the modified AISI 316 stainless steel can be applied in situations that needs mechanical and corrosion resistance simultaneously.