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 MoSi 2 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 MoSi 2 coating due to different thermal expansion coefficients compared with stainless steel, which has an important effect on the corrosion behaviors. In this paper, MoSi 2 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 MoSi 2 coating by refining the grain size and optimizing the expansion coefficient. The open circuit potential and corrosion potential of the MoSi 2 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 MoSi 2 coating was higher than that of the MoSi 2 + TiVAlZrNb composite coating. The obvious local corrosion originated from the cracks in the MoSi 2 coating. Therefore, the addition of TiVAlZrNb high-entropy alloy could optimize the cracking and corrosion resistance of MoSi 2 coating on LPBF high-strength stainless steel. • The crack and density of MoSi 2 coating was optimized by doping of TiVAlZrNb high-entropy alloy. • The obvious local corrosion originated from the cracks of MoSi 2 coating. • The corrosion resistance of MoSi 2 + TiVAlZrNb composite coating was higher than that of MoSi 2 coating. [ABSTRACT FROM AUTHOR]