Optimization the cracking and corrosion resistance of MoSi2 coating by addition of TiVAlZrNb high-entropy alloy on laser powder bed fusion high-strength stainless steel

The MoSi2 coating is an ideal coating system for stainless steel due to its good wear resistance and oxidation resistance in the sea service environment. However, there are always some cracks in the MoSi2 coating due to different thermal expansion coefficients compared with stainless steel, which has an important effect on the corrosion behaviors. In this paper, MoSi2 coatings on laser powder bed fusion (LPBF) high-strength stainless steel prepared by laser cladding technology were optimized by the addition of a TiVAlZrNb high-entropy alloy. The results showed that the addition of a TiVAlZrNb high-entropy alloy could optimize the cracks in the MoSi2 coating by refining the grain size and optimizing the expansion coefficient. The open circuit potential and corrosion potential of the MoSi2 coating were − 158 mV and − 262 mV, respectively, which were lower than those of the composite coating (148 mV and − 225 mV, respectively). The electrochemical impedance value of the MoSi2 coating was higher than that of the MoSi2 + TiVAlZrNb composite coating. The obvious local corrosion originated from the cracks in the MoSi2 coating. Therefore, the addition of TiVAlZrNb high-entropy alloy could optimize the cracking and corrosion resistance of MoSi2 coating on LPBF high-strength stainless steel.