In this paper the critical cooling rate, Rc, for the glass formation of Fe80P13C7 alloy has been determined using both Uhlmann＇s and Barandiaran-Colmenero＇s method. In Uhlmann＇s method, all kinds of the expres-sions of △G^l-s （T） and η/（T） determined using the different modes and methods had been investigated. It is indicated that the Rc for the glass formation of FesoP13C7 alloy can be estimated to be 349 K/s by Uhlmann＇s method based on the appropriate expressions of △G^l-s（T） and η/（T）. The calculated result accords with our experimental result. The Rc for the glass formation of Fe80P13C7 alloy has also been determined to be 0.49 K/s using Barandiaran-Colmenero＇s method. This resultant Rc is unreasonable low and it indicates that Barandiaran-Colmenero＇s method does not suit to Fe-based alloy.
Nanostructured Fe40Ni40P14B6 alloy ingots of 3―5 mm in diameter could be synthesized by a metastable liquid state spinodal decomposition method. For undercooling T> 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling T>290 K, the overall microstructure of the specimen changed into a granular morphology. The average grain sizes of the small and large grains are 30 nm and 80 nm, respectively. These prepared samples are soft magnets with saturation magnetization Bs 0.744 T.
LI Qiang1,2 1 School of Physics Science and Technology, Xinjiang University, Urumqi 830046, China
