Laser Cladding High Entropy Alloy Coating Resistant To Strong Acid Erosio

SUS 904L austenitic super-stainless steel is commonly used as stirring blade material in phosphoric acid production,but it has a low hardness,resulting in a low service life.In order to prolong the service life of 904L stainless steel,the high entropy alloy coating was designed by using cluster+glum atom model and was cladded on the surface of 904L austenitic stainless steel by laser cladding.In this paper,the high entropy alloy coatings of[(AlxTi1-x)-M12](AlxTi1-x)0.5Cr2.5 and[(AlxTi1-x)1-yMoy-M12](AlxTi1-x)0.5Cr2.5-zCuz were designed.The microstructure,hardness,corrosion resistance and wear resistance of the coatings were analyzed by XRD,SEM,TEM,EDS and electrochemical workstation.The results show that when x=0.5,Al and Ti elements tend to form B2 phase in the[(AlxTi1-x)-M12](AlxTi1-x)0.5Cr2.5 coatings,B2 phase is easy to corrode the corrosion of the coating.When x=0,the coating has the highest hardness of 402.3 HVo.2 and the lowest wear volume of 0.866 mm3.And the substrate is 209.0 HV0.2 and the wear volume of 1.515 mm3.Then Mo and Cu elements are introduced into the coating,and the results show that Mo and Cu elements can effectively improve the corrosion resistance of the coating.However,adding too much Mo and Cu elements will make the coating grain coarse,and hardness and wear resistance decrease.When the coating composition is[(AlxTi1-x)0.7Mo0.3-M12](AlxTi1-x)0.5Cr1.7Cu0.8,the coating has better overall properties,hardness is 299.7-333.6 HV0.2,and the lowest wear is 0.522 mm3.Finally,the effect of heat treatment process on the coating properties was studied.After annealing at 700℃ for 10 h,The element Ti is segregated towards grain boundary to form BCC phase.The corrosion resistance and hardness are increased,and the corrosion resistance is obviously improved.When x=1,the equivalent resistance of the coating is 19132 Ω,when x=0,the equivalent resistance of the coating is 16045 Ω,much higher than 9996 Ω of 904L stainless steel.The results show that the high entropy alloy coatings of[(AlxTi1-x)M12](AlxTi1-x)0.5Cr2.5 and[(AlxTi1-x)1-yMoy-M12](AlxTi1-x)0.5Cr2.5-zCuz have a certain ability to protect 904L stainless steel.