FeCoNiTiAl_x (x = 0, 0.5, 1) high-entropy alloy coatings were prepared by laser cladding technology. The phase, microstructure, hardness, wear resistance and corrosion resistance were tested and analyzed. The results showed Al element promoted the conversion from the FCC phase to the BCC phase. The coating presented dendritic structure due to the addition of the Al element, while the number of dendrites increased. And the average hardness of the coating increased from 204 to 623 HV. The addition of the Al element increases the corrosion current density of the coating from 1.270 × 10⁻⁵ to 3.489 × 10⁻⁵ A/cm². The wear rate of the coatings decreases with the increase of Al content according to dry friction and wear, which indicates the wear resistance of the coating was improved by adding the Al element. According to the corrosion wear test in 3.5% NaCl solution, it can be found that the wear rate of the coating increases firstly and then decreases with the addition of the Al element, which indicates that the addition of the Al element intensifies the wear of the coating in 3.5% NaCl solution.

This research centers around cast steel 20Mn, which is the material utilized for the ear-picking roller of a corn harvester. The study delves into methods of enhancing its hydrophobicity and wear resistance. Fiber laser-processing technology was employed to fabricate pangolin bionic micro-textures on the material surface, and PVD technology was utilized to deposit a TiN coating. The wear resistance of the modified surface was investigated via the reciprocating dry sliding wear method, while its hydrophobicity was concurrently examined. The results demonstrate that the laser texturing technology and TiN coating managed to reduce the friction coefficient of the sample surface by 20% and 30.9%, respectively. This can be chiefly attributed to the significant effects of the modified surface in augmenting hardness, diminishing the contact area of the friction surface, lowering shear stress, and entrapping wear debris. When the pangolin texture and TiN coating work in concert, the abrasive and fatigue wear between the two surfaces is conspicuously mitigated, and the friction coefficient is reduced by 38.09%. Moreover, the experiment also reveals that a superhydrophobic surface can be achieved by fabricating the pangolin micro-textures.

Ultrasonic surface rolling (USR) was applied to GCr15 steel with different static loads and passes to improve the friction and wear properties, and then the fretting wear mechanism of GCr15 steel after USR treatment was systematically investigated. The results showed that the specimens treated by the USR had lower surface roughness and significantly increased compressive residual stress and microhardness. Furthermore, severe plastic deformation occurred in the surface layer of the specimen, which refined the grains and increased the density of high- and low-angle grain boundaries. Besides, the results of the fretting test showed that the USR treated specimens had lower wear volume, dissipated energy, and steady-state friction coefficient. The fretting wear resistance increased with the static load and the number of passes. The fretting wear mechanism changed from abrasive wear and severe adhesive wear to slight fatigue wear and abrasive wear owing to the use of the USR treatment. Surface smoothing and hardening are responsible for the improvement in the fretting wear properties of GCr15 steel for USR treatment.