Effects of La addition on glass formation, crystallization and corrosion behavior of Gd-Al-based alloys

The effect of La addition on glass formation, crystallization and corrosion behavior of melt-spun Gd57.1 − xAl42.9Lax (x = 0, 4, 8 and 12 at.%) alloys has been investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), electrochemical measurements and field emission scanning electron microscopy (FESEM). The results show that the La addition can obviously enhance the glass forming ability and change the crystallization mode of the Gd-Al-based alloys. The inter-atomic distance increases with increasing La addition in the Gd-Al-based alloys. Moreover, the La addition can affect the initial crystallization products of the Gd-Al-based alloys and induce the precipitation of Gd2O3 phase from the amorphous matrix. Potentiodynamic polarization measurements demonstrate that the corrosion resistance of the as-spun Gd-Al-based alloys is not sensitive to the La addition in 3.5 wt.% NaCl solution. However, the as-annealed Gd-Al-La alloys have a better corrosion resistance than the as-spun alloys. The related mechanism has been discussed based upon the phase constitution, formation of oxide film and oxygen content.