Electrodeposition Elemental

Jain, A., S. Anthonysamy, G. S. Gupta, V. Ganesan, and P. R. Vasudeva Rao. 2011. Ssmthesis and characterization of electrodeposited elemental boron for control rod applications in fast breeder reactors, ht Abstracts of the 17th International Symposium on Boron, Borides and Related Materials, Istanbul, Turkey, p. 200. Javid, M., G. L. Brownell, and W. H. Sweet. 1952. The possible nse of neutron-capturing isotopes such as boron-10 in the treatment of neoplasms. B. Computation of the radiation energies and estimates of the effects in normal and neoplasm brain. J. Clin. Invest. 31 603-610. 

Attempts have also been made to electrodeposit elemental semiconductors like silicon [8], as well as compound semiconductors like III-V nitrides [9]. Other II-VI semiconductors like CdS [10], ZnSe [11], ZnTe [12-14], and ZnO [15,16] as well as SnS [17], which is a IV-VI compound semiconductor, have also been electrodeposited in addition to ternary compounds like CuInSe2 [18-22] and quaternary compounds like CuInGaSe2 [23-26] and Cu2ZnSnS4 [27]. 

Mengoli G, Musiani MM, Paolucci F (1991) Synthesis of indium antimonide (InSb) and indium gallium antimonide (In Gai. Sb) thin films from electrodeposited elemental layers. J Appl Electrochem 21 863... 

In this process, uranium metal is electrodeposited at the cathode, while plutonium and other transuranium elements remain in the molten salt as trichlorides. Plutonium is reduced in a second step at a metallic cathode to produce Cd—Pu intermetallics. The refined plutonium and uranium metals can then be refabricated into metallic fuel (137). 

Only about 10 elements, ie, Cr, Ni, Zn, Sn, In, Ag, Cd, Au, Pb, and Rh, are commercially deposited from aqueous solutions, though alloy deposition such as Cu—Zn (brass), Cu—Sn (bronze), Pb—Sn (solder), Au—Co, Sn—Ni, and Ni—Fe (permalloy) raise this number somewhat. In addition, 10—15 other elements are electrodeposited ia small-scale specialty appHcations. Typically, electrodeposited materials are crystalline, but amorphous metal alloys may also be deposited. One such amorphous alloy is Ni—Cr—P. In some cases, chemical compounds can be electrodeposited at the cathode. For example, black chrome and black molybdenum electrodeposits, both metal oxide particles ia a metallic matrix, are used for decorative purposes and as selective solar thermal absorbers (19). 

Making of Inorganic Materials by Electrochemical Methods 6.2.1.3 Electrodeposition of less noble elements... 

A1 is more noble than Ti, and so at room temperature only codeposits and alloys can be obtained. Furthermore, kinetic factors also play a role in the electrodeposition of the element. 

It was quite recently reported that La can be electrodeposited from chloroaluminate ionic liquids [25]. Whereas only AlLa alloys can be obtained from the pure liquid, the addition of excess LiCl and small quantities of thionyl chloride (SOCI2) to a LaCl3-sat-urated melt allows the deposition of elemental La, but the electrodissolution seems to be somewhat Idnetically hindered. This result could perhaps be interesting for coating purposes, as elemental La can normally only be deposited in high-temperature molten salts, which require much more difficult experimental or technical conditions. Furthermore, La and Ce electrodeposition would be important, as their oxides have interesting catalytic activity as, for instance, oxidation catalysts. A controlled deposition of thin metal layers followed by selective oxidation could perhaps produce cat-alytically active thin layers interesting for fuel cells or waste gas treatment. 

Indium and antimony The electrodeposition of In on glassy carbon, tungsten, and nickel has been reported [26]. In basic chloroaluminates, elemental indium is... 

Tellurium and cadmium Electrodeposition of Te has been reported [33] in basic chloroaluminates the element is formed from the [TeCl ] complex in one four-electron reduction step, furthermore, metallic Te can be reduced to Te species. Electrodeposition of the element on glassy carbon involves three-dimensional nucleation. A systematic study of the electrodeposition in different ionic liquids would be of interest because - as with InSb - a defined codeposition with cadmium could produce the direct semiconductor CdTe. Although this semiconductor can be deposited from aqueous solutions in a layer-by-layer process [34], variation of the temperature over a wide range would be interesting since the grain sizes and the kinetics of the reaction would be influenced. 

In the case of an electrochemical cell with a negative electrode consisting of an elemental metal, the process of recharging is apparently very simple, for it merely involves the electrodeposition of the metal. There are problems, however. 

Chemical vapor deposition (CVD) has grown very rapidly in the last twenty years and applications of this fabrication process are now key elements in many industrial products, such as semiconductors, optoelectronics, optics, cutting tools, refractory fibers, filters and many others. CVD is no longer a laboratory curiosity but a maj or technology on par with other maj or technological disciplines such as electrodeposition, powder metallurgy, or conventional ceramic processing. 

Electrodeposition of CdS has been carried out from aqueous and non-aqueous solutions containing precursors of both elements as well as by anodization of cadmium metal in sulfide solutions. 

Generally, the experimental results on electrodeposition of CdS in acidic solutions of thiosulfate have implied that CdS growth does not involve underpotential deposition of the less noble element (Cd), as would be required by the theoretical treatments of compound semiconductor electrodeposition. Hence, a fundamental difference exists between CdS and the other two cadmium chalcogenides, CdSe and CdTe, for which the UPD model has been fairly successful. Besides, in the present case, colloidal sulfur is generated in the bulk of solution, giving rise to homogeneous precipitation of CdS in the vessel, so that it is quite difficult to obtain a film with an ordered structure. The same is true for the common chemical bath CdS deposition methods. 

To overcome some of the problems associated with aqueous media, non-aqueous systems with cadmium salt and elemental sulfur dissolved in solvents such as DMSO, DMF, and ethylene glycol have been used, following the method of Baranski and Fawcett [48-50], The study of CdS electrodeposition on Hg and Pt electrodes in DMSO solutions using cyclic voltammetry (at stationary electrodes) and pulse polarography (at dropping Hg electrodes) provided evidence that during deposition sulfur is chemisorbed at these electrodes and that formation of at least a monolayer of metal sulfide is probable. Formation of the initial layer of CdS involved reaction of Cd(II) ions with the chemisorbed sulfur or with a pre-existing layer of metal sulfide. 

In practical terms, large-scale cracking in the produced films, detrimental to photoelectric applications, was the main drawback of the above method. In order to prevent the appearance of cracks, propylene carbonate (PC) has been used as a solvent, with encouraging results [51]. The mechanism of electrodeposition of CdS in PC solutions containing Cd(II) ions and elemental sulfur has been studied by performing cyclic voltammetry at stationary Pt and Au electrodes [52]. 

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