Effect of yttrium on thermal stability and crystallization behavior of Nd60Fe20Al10Ni10 amorphous alloys
Author(s): ZHANG Shasha, TIAN Xuelei, KONG Fanli
Pages: 735-740
Year: 2008 Issue: 5
Journal: Journal of Rare Earths
Keyword: Nd-based amorphous alloy; quenched-in crystals; thermal stability; crystallization behavior; activation energy; rare earths;
Abstract: The effect of yttrium on the thermal stability and crystallization behavior of Nd-Fe-Al-Ni amorphous alloys was investigated using X-ray diffraction (XRD), differential scanning calorimeter (DSC), and transmission electron microscopy (TEM).The results indicated that the as-cast Nd60Fe20Al10Ni10-xYx(x=0, 2) amorphous alloys were fabricated with some quenched-in crystals, which could be restrained by Y.With the effect of yttrium, both the crystallization temperature and exothermic peak shifted to higher temperatures, illustrating that the ther-mal stability could be improved. The addition of Y changed the crystallization process and final crystallization results. Moreover, the crystal-lites in the amorphous matrix became more homogeneous and smaller. Meanwhile, Y was useful for the passivation of oxygen in chemistry and restrained the negative effect of oxygen. The activation energies of the start of crystallization and peaking were 1.21 and 1.16 eV, respec-tively, according to the Kissinger equation.
Pages: 735-740
Year: 2008 Issue: 5
Journal: Journal of Rare Earths
Keyword: Nd-based amorphous alloy; quenched-in crystals; thermal stability; crystallization behavior; activation energy; rare earths;
Abstract: The effect of yttrium on the thermal stability and crystallization behavior of Nd-Fe-Al-Ni amorphous alloys was investigated using X-ray diffraction (XRD), differential scanning calorimeter (DSC), and transmission electron microscopy (TEM).The results indicated that the as-cast Nd60Fe20Al10Ni10-xYx(x=0, 2) amorphous alloys were fabricated with some quenched-in crystals, which could be restrained by Y.With the effect of yttrium, both the crystallization temperature and exothermic peak shifted to higher temperatures, illustrating that the ther-mal stability could be improved. The addition of Y changed the crystallization process and final crystallization results. Moreover, the crystal-lites in the amorphous matrix became more homogeneous and smaller. Meanwhile, Y was useful for the passivation of oxygen in chemistry and restrained the negative effect of oxygen. The activation energies of the start of crystallization and peaking were 1.21 and 1.16 eV, respec-tively, according to the Kissinger equation.
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