In-situ synthesized novel eyeball-like Al2O3/TiC composite ceramics reinforced Fe-based alloy coating produced by laser cladding

In this study, the precursor mixtures of Fe-Cr-C-B alloy powders and 0, 10 and 20 wt% Ti3SiC2 is successfully cladded on 16Mn steel substrate by laser cladding (LC). Microstructure and properties of composite coatings are explored by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectra (XPS), electrochemical workstation, Vickers hardness tester and UMT-2 tribo-meter. Results show that the phases in the composite coating with Ti3SiC2 addition mainly are super saturated solid solution α-Fe, hard phases such as eyeball-like Al2O3/TiC composite ceramics, Ti(B,C)2, TiC, Fe3C, γ-(Fe, Ni)/(Cr, Fe)23C6 laminar eutectics and Ti3SiC2 etc. The microhardness, wear and corrosion resistance of composite coatings increase with the weight percent of Ti3SiC2 increasing from 0 to 20%. The existence of super saturated solid solution α-Fe, hard phases such as Al2O3/TiC composite ceramics, Ti(B,C)2, TiC and Fe3C etc. and the Ti3SiC2 solid lubricant contribute to the higher microhardness and wear resistance. The increased corrosion resistance of coatings is attributed to the fact that Cr is the important element which increases the corrosion resistance of the composite coating. With Ti3SiC2 addition increasing, more Ti atoms are easy to interact with C atoms to form TiC carbides, which remain higher content of free Cr atoms in composite coatings.