Oxidation behaviors of Cr, Cr–7Fe, and Cr–2Al in air at 1173–1473 K

Alloying of Cr can mitigate its property limitations as accident-tolerant fuel (ATF) cladding material. In this work, the oxidation behavior and microstructural evolution of Cr-7Fe and Cr-2Al alloys in air at 1173-1473 K were investigated. Both alloys exhibited satisfactory oxidation resistance in air based on their high activation energies obtained from thermogravimetric analysis (TGA). The oxide layer composition and morphology evolution of surface and cross-section were determined by scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDS). The oxide phases were identified by x-ray diffraction (XRD) and texture coefficients were calculated. Residual stresses in Cr 2 O 3 layer were measured by XRD. Cr-7Fe showed an outer Fe 2 O 3 layer above Cr 2 O 3 , while Cr-2Al showed an inner Al 2 O 3 layer beneath Cr 2 O 3 , respectively. Adding minor alloying amounts of Fe and Al to Cr can potentially enhance its properties as cladding coating to Zr alloys.