Improving the corrosion behavior and wear resistance of steels by surface processing has got a lot of attention, economically. In this study, Fe/Al surface composite has been produced using plasma spraying and FSP. To fabricate surface composites, a Al-70wt.%Fe layer with a thickness of 100 m was coated on the low carbon steel substrate using plasma spraying and FSP was applied on these surfaces from one to four passes. FSP was also applied on the surface of steel samples with the same pass numbers in order to evaluate the effects of reinforcement particles on surface microstructure and properties. A tungsten carbide pin with the depth of 0.8 mm was used to perform FSP. The pin had the rotation speed and the traverse speed of 700 rpm and 80 mm/min, respectively. Two steel specimens with Al-Fe coating were heat treated at 900 for one and two hours to study the role of compounds in surface properties of composite samples. X-ray diffraction (XRD) analysis was used to identify the phases which formed on the surface composites and the heat treated samples. Optical microscopy and electron backscatter diffraction (EBSD( were utilized to study the microstructures. Besides, the Vickers micro-hardness profiles for different samples were measured. Linear reciprocating wear test was used for investigating the tribological performance of the stir zones (SZs). To evaluate the corrosion behavior of SZs the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests have been done in 3.5 wt.% NaCl solution. The results revealed that Fe-Al in-situ Fe-Al intemetallics have been formed on the surface composites. Widm?nsttaten ferrite plates have been formed in the SZs of the steel specimens as well as the surface composite, considerably. The micro-hardness of the SZs was increased by increasing the pass numbers both for steel and surface composite specimens. The SZs of the steel and surface composite which subjected to 4 FSP passes had the average hardness of 284 HV and 405 HV, respectively. The wear behavior of the SZs in both groups of samples was improved by increasing the pass number. The steel surface processed with 4 passes and the surface composite produced by 3 passes exhibiited the lowest wear rates in their groups. The dominant wear mechanism has changed from adhesive to abrasive by increasing the pass numbers in both types of the samples. However, pass numbers had no considerable effects of coefficients of friction (CoFs). The corrosion behavior of the steel specimens have been improved by increasing the pass numbers while the sample subjected to 4 FSP passes had the best corrosion resistance with polarization resistance (R P ) of 46769 K?.cm 2 . Between the surface composites, the sample which produced by one FSP pass showed the best corrosion behavior with the R P of 40940 K?.cm 2 and the highest corrosion potential.
