Amorphous nanocrystalline

Skyllas-Kazacos [14] proposed a different method of cathodic deposition with low-oxidation chalcogen precursors, involving cyanide aqueous solutions of elemental Se and Te, where the chalcogen was presumed to be present as SeCN or TeCN ions, respectively. Deposition results were only reported for CdSe and CdTe, indicating a nearly amorphous (nanocrystalline) nature of the films, which though did not contain free Se or Te. 

Varga LK, Bakos E, Kiss LF, Bakonyi I (1994) The kinetics of amorphous-nanocrystalline transformation for a Finemet alloy. Mater Sci Engin A 179 567-571... 

Sc considerably lowers the glass forming ability of Al alloys compared to rare earth metals (Ce). No amorphous phase was formed in rapidly solidified binary Al-Sc alloys. An unstable quasicrystalline icosahedral phase was first found in the alloy A185Sci5. Substitution of Ce for Sc in Al91Ce9 xScx alloys caused a transfer to a mixed amorphous-nanocrystalline and then to nanocrystalline structure. In Al85Nii0Ce5 xScx alloys a mixed amorphous-nanocrystalline structure appeared in the alloy with x=5 at a lowered solidification rate (increased ribbon thickness). 

The appearance of mixed amorphous-nanocrystalline and nanocrystalline structures strongly increased the ribbon hardness. 

Diffraction experiments combined with other techniques, such as different spectroscopic methods, will develop in the coming years. At present it is possible to carry out synchrotron X-ray diffraction experiments combined with for example Raman spectroscopy and extended X-ray absorption fine structure (EXAES) spectroscopy. Such experiments will help to clarify hydrogenation/dehydrogenation reactions involving for example amorphous/ nanocrystalline phases, as for example observed in several borohydrides. 

RS) of as-carbonized samples showed a strong double band in range of 1000-1600 cm 1 that is inherent to amorphous/nanocrystalline graphite-like carbon clusters. After carbonization the samples were oxidized at atmospheric pressure in flow of wet Ar(0.9 1/min) or dry Ar(0.9 l/min)/O2(0.3 1/min) mixture for 3 h at 650 °C, 800 °C and 950 °C. 

Shen TD, Koch CC, McCormick TL, Nemanich RJ, Huang JY, Huang JG (1995) The structure and property characteristics of amorphous/nanocrystalline silicon produced by ball milling. J Mater Res 10 139-148... 

The use of mechanical alloying as a processing technique to prepare amorphous, nanocrystalline and metastable phases is discussed by McCormick in ch. 160. Many times these states of matter are used as intermediates for forming equilibriiun materials ty additional processing steps. These include the rare-earth permanent-magnet materials SmCos, Nd2Fel4B and Sm2Fei7N. Also as described, this technique can be used to refine metals and compounds, and induce other chemical reactions at or near room temperature. 

G. Rixecker, P. Schaaf, U. Gonser, Depth selective analysis of phases and spin textures in amorphous, nanocrystalline and crystalline ribbons treated with an excimer laser. J. Phys. D Appl. Phys. 26, 870-879 (1993)... 

Gauthier, B., Tailleart, N., Eidelman, S., Book, D. and ScuUy, J. R. 2007a. Spray Applied Amorphous/Nanocrystalline Aluminum Alloy Coatings as a Replacement for Aluminum Cladding. In Tri-Service Corrosion Conference, 2007 Denver, CO. 

Lucente, A. M. and Scully, J. R. 2007b. Pitting of Al-based amorphous-nanocrystalline alloys with so Ae- easttaaD.oc[y i3Xs.ElectrochemicalandSolidStateLeners, 10,C39-C43. 

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