A Novel Compositional Design of [Cr-Fe4Co4Ni4]Cr2.6-xTixMo0.4 High-Entropy Alloy Coating Based on the Cluster-Plus-Glue-Atom Model and Its Mechanism of Resisting Strong Acid Erosion

To extend the service life of the agitator blade, a series of [Cr-Fe4Co4Ni4]Cr2.6-xTixMo0.4 (x = 0, 0.3, 0.6, and 0.9) high-entropy alloy (HEA) compositions based on the cluster-plus-glue-atom model is designed, and HEA coatings are deposited on 904L stainless steel using the laser cladding technique. The phase structure, microhardness, wear resistance, corrosion resistance, and erosion properties of the HEA coatings are determined using X-ray diffractometer, transmission electron microscope, a microhardness tester, a friction and wear tester, an electrochemical workstation, and an erosion testing machine, respectively. The coating's phase structure is made of FCC solid solution. The coatings' microhardness, wear, corrosion, and erosion resistance gradually improve by adding Ti. In particular, the microhardness of the [Cr-Fe4Co4Ni4]Cr1.7Ti0.9Mo0.4 coating reaches a peak value of 295.11 HV0.2, over 1.5 times that of the 904L stainless steel (190 HV0.2). Its specific wear rate (3.64 mm(3) N-1 m(-1)) is lower than that of the substrate (8.53 mm(3) N-1 m(-1)). The impedance of the [Cr-Fe4Co4Ni4]Cr1.7Ti0.9Mo0.4 coating is roughly 5.3 times of the 904L stainless steel. Simultaneously, the coating's cumulative volume loss rate of erosion-corrosion (0.054 mm(3) h(-1)) is lower than that of the substrate (0.063 mm(3) h(-1)). Consequently, the innovative HEA coating has an impressive overall performance.