Mechanical properties and corrosion resistance analysis of Fe-based amorphous-2 % CNTs coatings with low crack prepared by laser cladding

Fe-based amorphous alloys are widely used in industry due to their low cost and excellent mechanical properties. The high cooling rate of laser cladding technology provides a brand new technical means for Fe-based amorphous coatings (FeCrMo-G) to obtain more excellent properties. How to reduce cracks and increase the glass-forming ability (GFA) in the coatings of Fe-based amorphous coatings prepared by laser cladding is crucial to enhance the performance of Fe-based amorphous coatings. In this experiment, Fe-based amorphous composite coatings with fewer cracks were successfully prepared by adding 2 wt% carbon nanotubes (CNTs). The microstructure of the coatings showed that the addition of CNTs reduced the cracks on the surface of the coatings. The incorporation of CNTs effectively increases the amorphous content of the composite coating during laser melting. Mechanical property tests showed that the microhardness, coefficient of friction (COF), and resistance to plastic deformation of the composite coatings were improved. Among them, the wear rate of the Fe-based amorphous composite coating was 1.216 x 10-6mm3N-1 m-1, which was only 4.13 % of that of the Fe-based amorphous coating. The main wear mechanisms for composite coatings are slight abrasive wear and adhesive wear. The electrochemical test results show that because the self-corrosion current density of the composite coating decreases, and the corrosion rate of the coating decreases, thus improving the corrosion resistance of the composite coating. The main reason for the improved corrosion resistance is that CNTs play a bridging role on the surface of the composite coatings, which hinders the erosion of Cl-on the surface of the coatings.