酸性及高温熔盐介质中γ-TiAl合金的腐蚀行为OA

The corrosion behavior of γ-TiAl alloy,synthesized by vacuum self-propagating high-temperature synthesis,has been investigated in acidic and high-temperature molten salt media using electrochemical testing,static immersion experiments,and high-temperature molten salt experiments,combined with scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and X-ray diffraction(XRD)analysis.The results indicate that in a reducing hydrochloric acid solution,the corrosion current density of the alloy increases with an increase in HCl mass fraction.Especially in a 10％HCl(mass fraction)solution,the corrosion rate of the alloy continuously increases,exhibiting active dissolution characteristics and poor corrosion resistance.In an oxidizing sulfuric acid solution,the alloy displays a"critical effect",particularly in a 60％H2SO4(mass fraction)solution,where the alloy shows the lowest corrosion current density and the minimum corrosion rate,indicating optimal corrosion resistance.SEM results reveal that the lamellar structure of the alloy remains intact,and the dissolution of the γ-TiAl phase is inhibited.XRD results confirm the formation of a protective oxide film primarily composed of TiO2 on the alloy surface.In a high-temperature molten nitrate salt,after initial corrosion,a dense oxide film forms on the alloy surface,effectively inhibiting further corrosion,with no measurable weight loss observed in the later stages.