Investigation of microstructural and tribological behavior of (CrMnFeCoNi)Alx high entropy alloy coating developed by High Velocity Oxy-Fuel (HVOF)

High-entropy alloys (HEAs) are characterized as alloys containing five or more principal elements in equal or close to equal atomic percentage. Because of the high configurational entropy compared to conventional alloys, HEAs are usually composed of a simple solid solution phase instead of a complex, brittle structure. HEAs as bulk materials and coatings are considered potential candidate for high-temperature applications owing to their superior combination of mechanical and thermal properties. In the present study, the CrMnFeCoNi HEA coatings with different Al content were developed using high-velocity oxygen fuel (HVOF). The high velocity of the particles and low process temperature allows for the formation of a dense coating with limited porosity and oxide content. The wear behavior of these HEA coatings against alumina (Al2O3) ball was tested under the dry sliding conditions at room temperature. Ex situ characterization was performed using X-ray diffraction for phase analysis, SEM / FIB for cross-section microscopy and surface morphology identification. The powder particle size distribution, microstructural changes, phase compositions, microhardness, and wear performance of the various HEA coatings are discussed further in the paper. A strong emphasis is placed on the correlation between the interfacial processes and wear behavior of the various coatings.