Tribocorrosion performance of additively manufactured CuNi30 and SS-316L in marine environment: Seawater resistant alloys

Abstract

<p>This study presents the first systematic investigation of the tribocorrosion resistance of additively manufactured CuNi30 in artificial seawater (ASTM D1141-98), along with mechanical and tribocorrosion performance comparison against SS-316L. Both alloys were produced by laser powder bed fusion (PBF-LB/M), achieving relative densities of 99.8 % (CuNi30) and 99.1 % (SS-316L). The as-built CuNi30 exhibited a tensile strength of 503 MPa, which increased to 638 MPa after heat treatment at 550 °C for 2 h, reaching parity with SS-316L. Phase identification through X-ray diffraction confirmed the precipitation of Nb-rich precipitates (NbNi3) after heat treatment which contributed to the observed strengthening. The tribocorrosion performance was evaluated using a ball-on-disk setup, where potentiostatic, potentiodynamic, EIS, and COF measurements were recorded under both static and sliding conditions to assess corrosion-wear interactions. The results revelated that SS-316L is more susceptible to tribocorrosion damage due to its lower polarization stability and the formation of thin unstable third body layer. The calculated wear rate showed a decrease from 9.07 × 10−8 mm3/N·mm for SS-316L to 2.08 × 10−8 mm3/N·mm for heat-treated CuNi30, highlighting the superior tribocorrosion resistance of CuNi30.<br></p>