Microstructure and properties of in situ synthesized Fe-Al coating by laser cladding.

To improve the hardness and wear resistance of an aluminum alloy, Fe-Al intermetallic coatings are synthesized in situ on the surface of aluminum alloys by laser cladding. An x-ray diffractometer (XRD) and a scanning electron microscope are used to characterize the phase and microstructure of the coating. The corrosion resistance, wear resistance, and hardness of the coating were measured by an electrochemical workstation, a reciprocating friction and wear tester, and a Vickers hardness tester, respectively. There are no pores but some microcracks in the coating. The coating structure is composed of a dendrite crystal, a columnar crystal, and an equiaxed crystal. The XRD results show that the Fe-Al coating is mainly composed of body-centered cubic solid solution, FeAl phase, and Fe₃Al phase. At the same time, the average hardness of the coating reaches 601.54 Hv_0.2, which is approximately 5.9 times that of the substrate (101.8 Hv_0.2). Compared with the substrate, the self-corrosion voltage of the coating in 3.5% NaCl solution increased by 0.41 V, the self-corrosion current reaches 1.65 × 10⁻⁵ A, and the protection rate increased by 71%. [ABSTRACT FROM AUTHOR]