The effect of the substrate surface state on the morphology, topography and tribocorrosion behavior of Si/Zr sol-gel coated 316 L stainless steel

Abstract In the present work, a Si/Zr based sol–gel (SG) coating was deposited on 316 L stainless steel plates, previously treated by passivation (SSO) or electropolishing (SSEP) producing two different surface states. The SG coatings were compared for SSO and SSEP substrates in terms of morphology, topography and tribocorrosion response. The coating topography revealed a smoother surface for the Si/Zr-SSEP system. The coating deposited on the smoothest surface (Si/Zr-SSEP) presented half of the thickness of the one deposited on the roughest surface (Si/Zr-SSO). Tribocorrosion behavior was studied under potentiostatic control at anodic potential with a continuous recording of current (I) during sliding (pin-on-disc and alumina ball counterbody). Both SG systems showed an increase of current upon 100 sliding contact cycles indicating corrosion activity. After tribocorrosion tests, both systems revealed scratches, typical of abrasion, and coating removal in the wear tracks; the alumina counterparts presented accumulation of wear particles adhered to their surfaces. In conclusion, the initial surface state of the substrate modified the coating thickness, topography but did not significantly alter the tribocorrosion response of the studied SG systems.