Microstructure And Wear And Corrosion Resistance Of MCrAlY(Ta) Coatings Enhanced By Laser Melting Deposition Of CNTs/Al₂O₃

MCrAlY has good high temperature oxidation resistance and hot salt corrosion resistance,and has received extensive attention from researchers in recent years.However,the research on the performance of MCrAlY should not stop there.There should also be research on corrosion resistance and wear resistance.The reason is that some ships will work in areas and seas with severe acid rain for a long time.The acidic environment and sea water affect the parts of the ship.A certain degree of corrosion,which puts forward higher requirements on the corrosion resistance of the material.Therefore,this article uses laser melting deposition technology to prepare MCrAlY coatings.By adding the second phase,the influence of the second phase content on its corrosion resistance and wear resistance performance is studied.The main conclusions are as follows:(1)For CNTs/CoNiCrAlY composite coatings,the phases are mainly composed of Cr_mC_n,CNTs,?-(Ni,Cr),Al Co and Al Ni₃.The CNTs/CoCrAlTaY composite coating is mainly composed of CNTs,Ta C,Al Cr₂,Al₂O₃,Al Co,Si C,Cr_mC_n,Co Cr₂O₄ and Al₂Si O₅phases.The Al₂O₃/CoCrAlTaY composite coating is mainly composed of Ta C,Al Cr₂,Al₂O₃,Al Co,Si C,Crm Cn and Al₂Si O₅ phases.(2)In the study of wear resistance,it is found that the wear of composite coatings is mainly due to the coexistence of multiple wear mechanisms.In the composite coating with carbon nanotubes:as the content of CNTs increases,the hardness of the composite coating is improved,and the average hardness can be increased by a maximum of 1.5times;with the increase of CNTs content,the wear resistance of the composite coating gradually Enhanced,the wear rate can be reduced by up to 17.6 times.(3)The electrochemical test results of CNTs/CoCrAlTaY composite coating in0.5mol H₂SO₄ solution show that the addition of carbon nanotubes has a certain influence on the corrosion resistance of CoCrAlTaY composite coating.As its mass percentage increases,the composite The corrosion resistance of the coating gradually increased,but it was weaker than the corrosion resistance of the CoCrAlTaY coating.(4)The electrochemical corrosion test results of Al₂O₃/CoCrAlTaY composite coating in 3.5%Na Cl solution showed that:with the increase of alumina content,the corrosion resistance of composite coating gradually increased.In the topography after corrosion,it is found that the corrosion of the coating surface first starts from the areas where the dendrites or equiaxed areas are more distributed with alumina.