Yilmaz, Ummihan T.Erkan, AyseAkar, NesetKilicli, Volkan2025-01-212025-01-2120240025-53002195-8572https://doi.org/10.1515/mt-2024-0062https://hdl.handle.net/20.500.12587/24582This study investigates the influence of post-oxidation duration on the wear performance and microstructural features of AISI 4140 steel subjected to nitrocarburizing followed by post-oxidation. For this aim, the quenched and tempered AISI 4140 samples were nitrocarburized (NC) and post-oxidized (PO) at various times (45-180 min) under low vacuum. Microstructural features were investigated using optical microscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectrum analysis (EDS), X-ray diffraction (XRD) analysis, and microhardness test. Wear behavior was evaluated using a ball-on-disk tribometer. Experimental results showed that the structures consisting of nitride layer (epsilon-Fe2-3N) and gamma '-Fe4N + iron oxide (Fe3O4) were obtained at the top surfaces of the samples. Increasing post-oxidation times resulted in a notable enhancement in the thickness of the Fe3O4 layer. The growing Fe3O4 layer has induced the closing of micro porosities for further post-oxidizing times, leading to decreased surface roughness of the samples. It was determined that the post-oxidation times have no significant effect on the hardness profiles of NC + PO samples. The highest (0.375) and lowest (0.276) mean coefficient of friction was obtained in the post-oxidation times of 150 and 180 min, respectively. The best wear rate was obtained in the post-oxidized sample for 150 min.eninfo:eu-repo/semantics/closedAccessAISI 4140 steel; nitrocarburizing; post-oxidation; oxide layer; wear behaviorArticle66111782179410.1515/mt-2024-00622-s2.0-85205300979Q2WOS:001320992300001N/A