Comparative study on dry wear and tribocorrosion behavior of boronized martensitic stainless steels

https://doi.org/10.3221/IGF-ESIS.78.08

The tribocorrosion behavior of boronized 13Cr4Ni and 16Cr5Ni martensitic stainless steels (MSS) in 3.5 weight percent NaCl is examined in this work. Samples were tempered at 600 °C for two hours and boronized at 950 and 1000°C for six hours. Hard surface layers (≈1680–1805 Hv) with case depths of 35-90 µm were generated by boronizing. Icorr increased from 0.6-0.9 µA/cm² (bare) to 4.3-8.1 µA/cm² (boronized) and then to 14.3-27.1 µA/cm² under tribocorrosion. Potentiodynamic polarization showed a shift in corrosion potential by around 200–310 mV toward more active values. The coefficient of friction (COF) in dry sliding varied from 0.49 to 0.78, and wear rates ranged from 3.5 to 5.1 × 10⁻6 mm³/Nm. At 950 °C, wear rates decreased by 25 to 27% because of higher fracture toughness (3.3 to 3.9 MPa√m). Due to electrolyte lubrication, COF decreased to 0.28-0.49 (16-33% lower) under tribocorrosion. When compared to bare MSS, boronized samples showed noticeably better wear resistance, with wear reduction of 60-80%. Under tribocorrosion, wear mechanisms changed from sticky abrasive in dry sliding to mixed abrasion, adhesion, and tribo-oxidation, controlled by cyclic passivation–depassivation. Boronizing, particularly at 950°C, improves overall tribocorrosion performance despite decreased corrosion resistance by balancing hardness and toughness.