# Process Optimization and Wear Performance of Plasma-Cladding Fe5 Coatings on Rotary Tillage Blades
## 4 Conclusions  
An Fe5 wear-resistant alloy cladding layer was prepared using plasma-cladding technology, and the microstructural morphology, phase composition, microhardness, and wear resistance were analyzed. The following conclusions were drawn. (1) Using the wear mass of the cladding layer as the evaluation index, a Box-Behnken response surface methodology experiment with four factors and three levels was designed using the Design-Expert 13. The optimal process parameter combination was obtained as follows: a cladding current of 144 A, a cladding speed of 23 mm/s, a powder feeding rate of 23 g/min, and a cladding distance of 12 mm. (2) The Fe5 cladding layer exhibits excellent formation, with a clean and neat interface that is free from excessive porosity and inclusions, and it forms a strong metallurgical bond with the 65 Mn substrate. The microstructure of the cladding layer primarily consists of hard phases in the form of dense acicular, hexagonal, and triangular regions, as well as an iron-based bonding phase. The main phases of the hard phases are Cr\({}_{7}\)C\({}_{3}\) and Cr\({}_{2}\)Fe\({}_{14}\)C, while the remaining phases consist of \(\alpha\)-Fe and Cr-Ni-Fe-C solid solutions. (3) The average hardness of the Fe5 cladding layer is 1171 Hv0.5, which is approximately 2.9 times that of the substrate. In wet sand rubber wheel wear tests under identical operating conditions, the weight loss due to wear of the Fe5 cladding layer is only 1/21 that of 65 Mn steel, demonstrating excellent wear resistance. (4) Field trials demonstrated that the wear of rotary tiller blades with cladding layers was reduced by 24.5% compared with those without cladding layers. The wear performance in the field trials was lower than that observed in the wet sand rubber wheel tests, primarily because in the latter, abrasive particles only came into contact with the surface of the coating. In contrast, during the field trials, the back and cutting edge of the blade, which were not protected by the coating, were also subjected to abrasive action. Consequently,  
Figure 12: The morphology of rotary tillage blades with and without Fe5 coatings (**a**) pre-test rotary tillage blades with Fe5 coating; (**b**) post-test rotary tillage blades with Fe5 coating; (**c**) pre-test rotary tillage blades without Fe5 coating; (**d**) post-test rotary tillage blades without Fe5 coating. The red portion indicates the area of the rotary tiller blade that has experienced wear. the data from the field trials often exhibited poorer performance than those from bench tests. Macroscopic examination of the wear morphology revealed that the wear of rotary filler blades was mainly concentrated at the bend angle and the cutting edge. The presence of a cladding layer effectively mitigated the wear process, ensuring that the cutting edge remained relatively intact even after prolonged operation, thereby extending the service life of rotary filler blades. The optimized Fe5 coating demonstrated excellent wear resistance under actual field conditions. This advantage can also be utilized beyond rotary filler blades in other soil cultivation equipment, thereby enhancing their service life. Furthermore, in non-agricultural scenarios such as mining machinery, steam turbine rotor shafts, valve wear, and pump maintenance, the Fe5 coating holds significant potential for application in the repair and remanufacturing of these devices. In the next phase, we will focus on investigating the wear mechanisms of Fe5-coated rotary filler blades and exploring their applications in other wear-related contexts. Conceptualization, M.W., Z.W. and M.L. ; methodology, J.Z. ; software, J.Z. and Y.M. ; investigation, J.Z., Y.M., M.W. and Z.W. ; resources, J.Z. ; writing--original draft preparation, J.Z. ; writing--review and editing, Z.F. and Z.W. ; supervision, Z.W., M.W. and M.L. ; project administration, Z.F. and Z.W. ; funding acquisition, Z.F. and Z.W. All authors have read and agreed to the published version of the manuscript.