Amorphous metal alloy films

Attempts were made to describe theoretically the current flowing at microelectrodes under various conditions, including also migrational transport. Deposition of monomolecular Langmuir-Blodgett films at electrodes, their different properties, as well as electrodeposition of amorphous metallic alloys were studied. 

The passive films formed by the addition of sufficient amounts of valve metals to amorphous nickel-valve-metal alloys are exclusively composed of valve-metal oxyhydroxides or oxides such as TaOjCOH) , Nb02(OH) or TajO,. Consequently, amorphous alloys containing strongly passivating elements, such as chromium, niobium and tantalum, have a very high ability... 

Environmental tests have been combined with conventional electrochemical measurements by Smallen et al. [131] and by Novotny and Staud [132], The first electrochemical tests on CoCr thin-film alloys were published by Wang et al. [133]. Kobayashi et al. [134] reported electrochemical data coupled with surface analysis of anodically oxidized amorphous CoX alloys, with X = Ta, Nb, Ti or Zr. Brusic et al. [125] presented potentiodynamic polarization curves obtained on electroless CoP and sputtered Co, CoNi, CoTi, and CoCr in distilled water. The results indicate that the thin-film alloys behave similarly to the bulk materials [133], The protective film is less than 5 nm thick [127] and rich in a passivating metal oxide, such as chromium oxide [133, 134], Such an oxide forms preferentially if the Cr content in the alloy is, depending on the author, above 10% [130], 14% [131], 16% [127], or 17% [133], It is thought to stabilize the non-passivating cobalt oxides [123], Once covered by stable oxide, the alloy surface shows much higher corrosion potential and lower corrosion rate than Co, i.e. it shows more noble behavior [125]. 

Luborsky, F.E. (1987) Amorphous transition metal-rare earth alloy films for magnetooptical recording. Materials Research Society Symposium Proceedings, 80 (Science and Technology of Rapidly Quenched Alloys) 375-394. 

The TCR value of an amorphous alloy strongly correlates with its specific resistance [49]. It also corresponds to the thermal effect on the specific resistance, i.e., the TCR increases at the temperature where the specific resistance abruptly decreases. The TCR values of alloys containing refractory metals exceed those of NiP NiReP alloy film annealed at 500°C in particular has an excellent TCR of 18 ppm K [36]. Although the TCR of as-plated crystalline NiMoP is lower than TCR values of amorphous alloys, heat treatment at 500 C slightly decreases the TCR to 134 ppm , which is a relatively high value, while the value measured after... 

Both crystalline [168] and amorphous [169] alloys are considered as precursors in the preparation of HTSC films. Atomic-level uniformity of the component distribution in metallurgical alloys can be achieved. One more type of metal precursor, the oxidation of which gives good results under relatively mild conditions, are multilayer polymetallic coatings with nanometer-thick layers [170], Similar compositions are also the most frequently used type of precursors in the technology of semiconductors [171]. 

During the past few years the microhardness technique has frequently been applied to the characterization of super-hard-surfaced polymers obtained by ion implantation and to plasma-deposited hard amorphous carbon films (Balta Calleja Fakirov, 1997). These products represent an entirely new class of materials that are lightweight and have the flexibility of polymers combined with a surface microhardness and wear resistance greater than those of metallic alloys (Lee et al., 1996). 

Some of the voluminous literature on the oxidation and corrosion of aluminum and its alloys has a direct bearing on DMO. Pure aluminum is normally covered by an amorphous native oxide film which is partially converted to 7-alumina at the interface between the parent metal and the amorphous oxide when heated to 450°C in dry air [7-9]. This unusual behavior is explained by growth of the amorphous phase, through outward cation migration, while thickening of the 7-alumina is by epitaxial growth on the parent metal, controlled by inward oxygen diffusion. Termination... 

Examples of binary amorphous Tb-Fe alloys for magneto-optical applications were presented by Tsunashima et al. (1981), Honda et al. (1983b) and Kobayashi et al. (1981, 1983). The former authors used amorphous double layer films Gd-Fe/ Tb-Fe, in which the exchange coupling between those films had led to improved writing characteristics. Amorphous alloys in which Tb is combined with two different 3d metals were investigated by Tsujimoto et al. (1983), while Tsujimoto et al. (1980) studied the magnetic properties of multilayered amorphous films. 

Apart from the amorphous rare earth base materials mentioned above, numerous other amorphous metals and alloys have been studied. Collver and Hammond (1973) made a systematic study of amorphous transition metal films obtained by vapour deposition on cryogenic substrates. The superconducting properties of these amorphous alloys show clear differences with those of crystalline alloys. The 7J, values of the latter vary continuously with valency and give rise to two sharp peaks for electron-to-atom ratios equal to 4.5 and 6.5, respectively (Matthias, 1957). In contrast, the Tq values of the amorphous alloys show a more moderate variation with... 

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