Investigation of wear and corrosion performance of boron carbide (B4C) coated AISI 316L stainless steel produced by additive manufacturing

Additive manufacturing technology has become increasingly widespread in the aerospace industry in recent years as complex parts can be produced. AISI 316L is used in fuel systems, engine components and structural parts in the aviation industry. In this study, B4C was coated by thermoionic vacuum arc method to improve the corrosion and wear properties of AISI 316L samples produced by SLM method. Microstructure and phase analyses of the samples were carried out using FESEM, AFM and XRD techniques. Corrosion performance was investigated by electrochemical methods in aqueous solution containing 3.5% NaCl. In addition, specific wear rate and coefficient of friction were analysed by using pin-on-disc method in dry environment. The results obtained show that B4C coating is successfully coated on the surface of AISI 316L produced by SLM method and this is confirmed by FESEM, AFM and XRD analyses. When the microstructure of the uncoated sample is examined, it is seen that the dendritic structure is observed in the microstructure due to the SLM method, while the surface homogeneity and regularity are significantly increased in the coated sample. Free corrosion potentials of coated AISI 316L specimens produced by additive manufacturing and conventional method were found to be more anodic than uncoated specimens. When the anodic polarisation curves were examined, the presence of passivation zones was observed in both coated and uncoated samples, and it was determined that the corrosion rate of coated samples was lower. The coefficient of friction of coated and uncoated AISI 316L materials produced by conventional production was higher than the coated and uncoated AISI 316L materials produced by additive manufacturing. The average coefficient of friction of the AISI 316L sample produced by additive manufacturing was 0.58, while this value decreased to 0.46 after coating. On the other hand, the highest specific wear rate was found in AISI 316L- Additive manufacturing- Uncoated sample (0.29 mm3/N/m) and the lowest specific wear rate was found in AISI 316L- Conventional manufacturing- Coated sample (0.11 mm3/N/m). Keywords: Additive Manufacturing (SLM), AISI 316L, Corrosion, Wear, Boron Carbide