Microstructure and performance of AlCoCrFeNiCu(CeO2)X high-entropy alloy coatings by plasma cladding

AlCoCrFeNiCu(CeO ₂) _X (x=0 wt%, 0.3 wt%, 0.6 wt%, 0.9 wt%, and 1.2 wt%) HEA coatings were applied via plasma cladding technology to a 35CrMo steel surface in this investigation. Electron back-scattering diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to analyze the phase composition and microstructure of the coatings. A microhardness meter, a nanoindenter, a wear test machine, and an electrochemical station were used to assess the coating performance. The findings demonstrate that the phase composition of the coatings is unaffected by the addition of CeO ₂, with all coatings consisting of FCC and BCC phases. CeO ₂ was added to the coatings to refine their grain size and increase their proportion of high angle grain boundaries (HAGBs), BCC phase content, and geometrically necessary dislocation (GND) density. These improvements led to significant increases in the microhardness and wear resistance of the coatings. The 0.3 wt% CeO ₂ coating has the best corrosion resistance, which is caused by a number of factors including the element distribution, grain size, content of each phase, and phase distribution of the coatings. The corrosion resistance of the coating increases and then decreases nonlinearly with increasing CeO ₂ content.