Melt spun ribbon

It should also be noted that the crystallization behavior of melt-spun ribbons may be different on both ribbon sides [4.18]. Nucleation for primary crystallization of the transition metals is observed on both sides of the glassy ribbons, while other crystallization reactions have been observed to prefer usually either the free surface or the contact side of the ribbon [4.77]. This phenomenon may lead to different structural and chemical properties of the two ribbon sides, and consequently also to large anisotropy in the catalysts prepared from such ribbons [4.18, 19]. 

Figure 4. Quasicrystalline particles in Al93Fe3Cr2Ti2 melt-spun ribbon, dark field image...

Magnetic properties of R2Fel4B compounds obtained after crystallization of melt-spun ribbons were studied by Tao and Hadjipanayis (1985). 

Lee, R. W., Brewer, E. G. Schaffel, N. A. (1985). Processing of neodymium-iron-boron melt-spun ribbons to fully densed magnets. IEEE Transactions on Magnetics, MAG-21, 1958-63. 

Fig. 27. TEM bright-field micrographs of (a) Nd4 5Fe77B,8 5, (b) Nd4 5Fe76,8Bij,5C%2> (c) Nd4 5Fe75gBi8jCU( Nb (, and (d) Nd45Fe76.oB j.5Nbm melt-spun ribbons which were crystallized at 933 K for 10 min. The average grain size is about 30, 17, 12, and 43 run, respective. ...

The technological interest stems primarily from the fact that melt-spun ribbons have usually much better mechanical properties than crystalline compounds, which are brittle and have a tendency to fracture. These latter properties are highly undesirable in the fabrication of high-field superconducting magnets and devices. 

Cri] XRD, Mossbauer spectrometry, zero-field-cooled and field-cooled magnetization measiuements CoioCugoFcio, structure and magnetic properties of as-quenched and annealed melt-spun ribbon... 

Fig. 7 compares the DSC curves for the [(Fea8Coo.2)a75Ba2Sio.o5]%Nb4 bulk amorphous alloy rods with different diameters up to 25 mm with the data for melt-spun ribbon of the same composition. No appreciable difference is recognized in the transformation temperatures or... 

One of the most important problems relative to the synthesis of these materials remains the formation of new phases and structural inhomogeneities inside the matrices. From XRD after heat treatment at 740 K of NdFeB melt-spun ribbons, Strzeszewski et al. (1990) have pointed out four phases Nd, Nd203, and two (Nd,Fe)0 iron-rich phases (with tetragonal and hexagonal structures, 70 at.% and 85 at.% Fe, respectively). TEM imaging showed that such phases were present as spherical grains. As different kinds of... 

Li Fe + Nd2Fe,4B(Ti) + T2. In the Nd-rich region Tj phase, Tj phase and rich-Nd solid solutions solidify from the liquid at the end point of the liquid. The phase diagram of as-cast buttons and melt-spun ribbons with the composi-... 

Fass et al. (1987, 1988a) and Fass and Eliezer (1989) have used polarization tests to study the corrosion behaviour of a melt spun ribbon of Al-8%Fe alloy with and without additions of 4%Er, in 3.5% NaCl solution. They found that the presence of Er lowers E pit, increases /pass in the passive range, and reduces AE (the difference between Econ and Epit), when compared to the Al-8%Fe alloy. These results indicate that Er additions reduce the corrosion resistance of the Al-Fe alloy. 

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