Bulk amorphous formation and magnetic properties of Nd-Fe-Co-Al alloys by the new gas jet flow type levitating process

The amorphous formation ability and the magnetic properties of Nd ₆₀Fe _30-xCo _xAl ₁₀ (x = 10, 15, 20 or 30) alloys in the containerless process were studied by the new gas jet flow type levitating process. The gas jet flow type levitating process enables solidification without any container wall by the inert gas jet. The samples were solidified at the cooling rate of around 100 K/s. Then, the undercooling of samples exhibits high values (ΔT = 60-150 K). From X-ray diffraction measurements, the Nd ₆₀Fe3 _0-xCo _xAl ₁₀ samples exhibit a typical broad diffraction pattern for an amorphous structure. The DTA curves of x = 10, 15 and 20 showed an exothermic peak due to the crystallization. That is, it was revealed that the Nd ₆₀Fe _30-xCo _xAl ₁₀ samples formed bulk amorphous. Also, the coercivity is 1.6, 3.3 and 3.6kOe for the Nd ₆₀Fe ₂₀Co ₁₀Al ₁₀, Nd ₆₀Fe ₁₅Co ₁₅Al ₁₀ and Nd ₆₀Fe ₁₀Co ₂₀Al ₁₀, respectively. From the thermomagnetic curves, the Curie temperature is determined to be 463, 482 and 482 K for the Nd ₆₀Fe ₂₀Co ₁₀Al ₁₀, Nd ₆₀Fe ₁₀Co ₂₀Al ₁₀, and Nd ₆₀Fe ₁₀Co ₂₀Al ₁₀, respectively. In the M-H loops and the thermomagnetic curves, this difference between x = 10 ana x = 15, M may depend on tne microstructure.