Corrosion behavior of 316L stainless steel reinforced by dispersed yttria stabilized zirconia fabricated by spark plasma sintering

Abstract

This paper evaluates the corrosion behavior of 316L stainless steel (SS316L) matrix composites reinforced with 3% yttria-doped zirconia (3Y·ZrO2), fabricated using the spark plasma sintering. Four different compositions were produced (SS316L, SS316L-5%vol. 3Y.ZrO2, SS316L-10% vol. 3Y.ZrO2, and SS316L-20% vol. 3Y.ZrO2) and primarily assessed for their corrosion resistance evaluated via immersion tests and electrochemical impedance spectroscopy (EIS). Additionally, densification, surface morphology, microstructure and mechanical properties were characterized as complementary. Densification was measured using the Archimedes method, while surface and microstructural characteristics were analyzed using optical and scanning electron microscopy. Mechanical properties were determined through microhardness testing. The results indicate that higher 3Y·ZrO2 content decreases densification and induces porosity, which contributes to localized corrosion. Despite the presence of porosity, microhardness improved with increasing 3Y·ZrO2 content. Additionally, immersion and EIS tests revealed that 5% of 3Y·ZrO2 enhances corrosion resistance. However, in composites with 10% and 20% 3Y·ZrO2, porosity compromises corrosion resistance by degrading passivation. Notably, composites with 5% 3Y·ZrO2 demonstrated significantly better corrosion resistance compared to pure SS316L and the other compositions, highlighting their potential for practical applications.

Keywords

• Stainless steel
• Zirconia
• Composite
• Spark plasma sintering
• Microstructure
• Electrochemical corrosion