Wearing Behavior of the α-Al9FeMnSi Intermetallic Compound Formed by Reactive Sintering onto AISI 304L Stainless Steel

Abstract

In this study, using mixtures of pure Al, Si, Mn, and Fe powders, the α-Al9FeMnSi intermetallic compound was formed onto AISI 304L stainless steel samples by reactive sintering. The processing parameters were temperature (800, 850, and 900 °C) and applied pressure (15 and 20 MPa), using a constant holding time of 7200 s. In this paper, the influence of pressure and temperature on the microstructure, microhardness, and wear resistance of the formed layers was studied. Using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness testing, and wearing measurements (pin on disc tests), the cross-section and top side of the coatings were observed and analyzed. We were able to determine the phase composition of cladded layers and interfaces as well as their morphology. The results indicated that several layers were formed during reactive sintering, i.e., an Al-diffusion layer on the top of the substrate, an interface, and the α-Al9FeMnSi coating itself. The microhardness values of the different layers formed were determined, ranging from 400 to 500 HV for the intermetallic coating, to 120 HV for the substrate. In this way, it was found that the formed intermetallic coating is suitable to increase the corrosion resistance of stainless steel. Additionally, all the coating showed high adherence to the substrate, exhibiting high microhardness and wear resistance. Pin on disc wearing tests showed the wearing mechanisms are predominantly delamination and ablation of the cladded layers and substrate.