Zr-based amorphous alloy

The gradient value is about one-tenth as large as that (about 2.0 T/K) (Johnson 1978 and Inoue et al. 1981) for amorphous superconductors in Zr-, Nb- and Mo-based alloys. This significant difference is thought to reflect the difference in electrons contributing to superconductivity, i.e., heavy d-electrons for the M-based amorphous alloys and s- and p-electrons for the Al-based amorphous alloys. 

Recent Progress of Zr-Based Bulk Amorphous Alloys, A, Inoue, Sci. Rep. RITU, A42, (1996) 1-11, No. 1, March 1996... 

Similarly, a number of amorphous alloys based on Fe-Zr, Ni-Zr, Co-Zr, Ni-Nb, have not shown any increase in activity over that expected for the mechanical mixture of the crystalline components [571]. For Ni-Nb the overpotential has even increased. Only Cu-Ti alloys have shown apparent synergetic effects, but the results of Machida et al. [89] (cf. Fig. 32) should also be taken into account. Jorge et al. [152] have observed higher activity for the amorphous form of Cu-Ti alloys, but they have attributed it to the preferential dissolution of Ti in the amorphous sample under cathodic load, with formation of a relatively porous Cu layer. The same effect was obtained more rapidly by means of HF etching [89,152]. 

Elinvar behavior is, also, found in concentrated Nb—Zr and Nb—Ti alloys. Furthermore, some amorphous alloys, e.g., in the Fe—B-, Fe—P-, and Fe—Si—B-based systems, show elinvar behavior. Ex-arrqtles for amorphous Fe—B alloys are shown in Fig. 4.3-54. 

In order to further reduce the use of Pd, Paglieri et have investigated amorphous alloys based on Ni-Nb-Zr. In particular, they have systematically studied the effects of Ta addition on the performance of a series of Ni-Nb-Zr amorphous alloys with various Zr content. A series of amorphous alloy membranes consisting of Ni b2oZr2o, (Nio6Nbo.4)ioo.4Zr and (Nio 6Nbo3Tao.i)ioo- cZr , (where x = 0,10,20 and 30) were prepared using melt... 

The full substitution of Zr by Nb is important since the oxygen reactivity of Nb is lower than that of Zr or Hf, and because the amorphous precursors of some Fe-Nb-B based alloys can be prepared under ambient atmosphere [70], making NANOPERM mass producible. 

Amorphous metals can be prepared in a wide variety of stable and metastable compositions with all catalyti-cally relevant elements. This synthetic flexibility and the isotropic nature of the amorphous state with no defined surface orientations and no defect structure (as no long-range ordering exists) provoked the search for their application in catalysis [21]. The drastic effect of an average statistical mixture of a second metal component to a catalytically active base metal was illustrated in a model experiment of CO chemisorption on polycrystalline Ni which was alloyed by Zr as a crystalline phase and in the amorphous state. As CO... 

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