Performance Evaluation Of The A1-Based Amorphous Alloy Coating And Composition Optimization And Design Of Corrosion Resistant Amorphous Al Alloys

Al-based amorphous alloy has excellent corrosion resistance and wear resistance due to its unique structural characteristics.However,at present,the research on aluminum based amorphous coating is in the infancy stage.The comprehensive evaluation of the performance of the Al-based amorphous alloy coating and the targeted optimization of the alloy composition to make it meet the requirements of practical service conditions have obvious significance for promoting the engineering applications of Al-based amorphous alloys.Based on the five-element system Al-based amorphous alloy Al₈₆Ni₆Y_4.5Co₂La_1.5?Al-AM?,the amorphous Al coating was prepared by supersonic flame spraying?HVAF?,and the mechanical properties and corrosion resistance of the coating was comprehensively evaluated.In order to further improve the corrosion resistance of the coating,the composition optimization of Al-AM amorphous alloy was carried out by microalloysing of Cr,Ti,Mo and Ce elements or partial substitution of La.The main conclusions are as follows:?1?Three different pretreatment processes?i.e.untreated substrate surface,milling by sand paper,and sand blasting?was carried out before Al base amorphous coating.The matrix by sandblasting processing.The coating properties is the best for the sampel ptetreated by sand blasting of the substrate.The porosity of the coating was 0.5%and the bonding strength was 62.36 MPa,and the coating without any observable crack processed higher shock resistance.The electrochemical polarization test results showed that the corrosion potential of Al-based amorphous coating increased by about 100²00 mV,the corrosion current density decreased by about 1² orders of magnitude compared with 2024 matrix,and the passivation interval width was about 100 mV.?2?The effect of microalloying on the corrosion resistance of transition metals was studied by preparing samples with different contents(Al₈₆Ni₆Y_4.5Co₂La_1.5)_100-X?TM?_X thin ribbons.The addition contents of Ti,Mo and Cr elements were 0.5,1.0 and 1.5?at.%?,respectively.Ti and Mo elements addition did not change the original structure of the alloys,all the alloys were completely amorphous,while the Cr elements addition depended greatly on the content.When the Cr elements were higher than 1.0%,the structure of the alloy changed to partially amorphous.Electrochemical tests showed that the corrosion resistance of Al-AM alloy hardly changed by the addition of Ti element.While the addition of Mo and Cr elements of 0.5%and 1.0%greatly improved corrosion resistance,and the corrosion current density was reduced by about 1² orders of magnitude,and the pitting corrosion potential was increased by about 60⁸0 mV_SCE.?3?The influence of Ce element on electrochemical corrosion of AL-AM alloy was also analyzed.Al₈₆Ni₆Y_4.5Co₂La_0.75Ce_0.75?AlCe-1?and Al₈₆Ni₆Y_4.5Co₂Ce_1.5?AlCe-2?ribbons are fully amorphous.The pitting potential of AlCe-1 and AlCe-2 alloys was about 60 mV_SCE and140 mV_SCE higher than that of Al-AM alloy respectively.The passivation film of AlCe-2amorphous alloy formed by anodic polarization in air and neutral chloride ion solution is thicker and has better corrosion resistance than that of Al-AM amorphous alloy.