Abstract: Cr_2AlC bulk material was prepared insitu by hot pressing sintering using Cr₃C₂, Cr and Al as the starting materials. The samples were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The reaction process was investigated by means of differential scanning calorimetry (DSC). The corrosion properties of Cr₂AlC in the acid and alkali solutions were obtained by weight loss method. The XRD result shows that high purity Cr₂AlC bulk material can be synthesized by hot pressing with n(Cr₃C₂)∶n(Cr)∶n(Al)=0.5∶0.5∶1.2 at 1350℃ for 2h under 30MPa. The XRD patterns in different temperatures suggest that the reaction process of starting materials is that Al melts at first, then Cr5Al8 generates at 700℃, Cr₂AlC is produced with the temperature elevation by the reaction of Cr₅Al₈ and Cr₃C₂ at last. SEM images of fracture faces of the sintered sample show the laminated and well plateshaped grains with a mean particale size of 6.4μm. Cr₂AlC exhibits low weight loss except immersion in the concentrated H₂SO₄ and HCl solutions. The weight loss is negligible after immersing samples in the concentrated and dilute NaOH solutions for 150d and the corrosion rates are only 0.4 and 0.7μm/a, respectively.

Key words: hot pressing, Cr₂AlC, corrosion properties, weight loss method