Improving the Na2SO4-induced corrosion resistance of Ti3AlC2 by pre-oxidation in air

Ti 3 AlC 2 suVers severe Na 2 SO 4 -induced corrosion attacks at temperatures higher than 800 °C in air. A convenient and eYcient pre-oxidation method is proposed to enhance the corrosion resistance of Ti 3 AlC 2 . The corrosion weight-changes of the pre-oxidized samples were decreased by about four orders of magnitude compared with those of the untreated specimens. The mechanism on improvement of corrosion resistance was investigated by means of thermogravimetric analysis, X-ray diVraction and scanning electron microscopy/energy-dispersive spectroscopy. A continuous and adherent -Al 2 O 3 scale was prepared by high-temperature pre-oxidation treatment in air. The preformed dense Al 2 O 3 scale has good compatibility with the Ti 3 AlC 2 substrate, and consequently, can act as an eYcient barrier against corrosion. Long-time corrosion tests demonstrate that the Al 2 O 3 scale conserves after corrosion attack and is capable of long-term stability. © 2005 Elsevier Ltd. All rights reserved.