High-Temperature Tribological Behavior of a Laser-Additively Manufactured CoCrNiFeAl-30 wt.% Cr3C2 Coating
摘要
Dry sliding tests at 550, 750, and 950 °C were conducted to investigate the high-temperature tribological behavior of a laser-additively manufactured CoCrNiFeAl-30 wt.% Cr3C2 coating on 316L stainless steel. The coating exhibited a dense heterogeneous microstructure composed of FCC and BCC solid-solution phases together with Cr3C2 and Cr7C3 carbides. The friction coefficient changed only slightly with temperature, whereas the wear rate showed a non-monotonic variation, decreasing from 0.55 × 10−5 mm3 N−1 m−1 at 550 °C to 0.33 × 10−5 mm3 N−1 m−1 at 750 °C and then increasing to 1.16 × 10−5 mm3 N−1 m−1 at 950 °C. SEM/EDS, XRD, and XPS analyses revealed progressively intensified tribo-oxidation with increasing temperature. However, the strongest oxidation at 950 °C did not produce the best wear resistance. The lowest wear rate at 750 °C was attributed to a better balance between oxidation-assisted surface protection and the mechanical stability of the sliding-induced tribochemical layer.