Cobalt manganese oxide films

A critical issue is the stabiUty of the hydride electrode in the cell environment. A number of hydride formulations have been developed. Table 5 shows hydride materials that are now the focus of attention. Most of these are Misch metal hydrides containing additions of cobalt, aluminum, or manganese. The hydrides are prepared by making melts of the formulations and then grinding to fine powers. The electrodes are prepared by pasting and or pressing the powders into metal screens or felt. The additives are reported to retard the formation of passive oxide films on the hydrides. 

Finely divided metals (without oxide film) Aluminum, calcium, cobalt, iron, magnesium, manganese, palladium, platinum, titanium, tin, zinc, zirconium... 

Cobalt in Driers for Paints, Inks, and Varnishes. The cobalt soaps, eg, the oleate, naphthenate, resinate, Hnoleate, ethyUiexanoate, synthetic tertiary neodecanoate, and tall oils, are used to accelerate the natural drying process of unsaturated oils such as linseed oil and soybean oil. These oils are esters of unsaturated fatty acids and contain acids such as oleic, linoleic, and eleostearic. On exposure to air for several days a film of the acids convert from Hquid to soHd form by oxidative polymeri2ation. The incorporation of oil-soluble cobalt salts effects this drying process in hours instead of days. Soaps of manganese, lead, cerium, and vanadium are also used as driers, but none are as effective as cobalt (see Drying). 

The electrochemical oxidation of tyramine in NaOH/MeOH media gives films of polytyramine (25). The film, on a platinum electrode, can complex copper(II) ions from aqueous media and cobalt(II), iron(II), manganese(II) and zinc(II) from organic media. X-ray photoelectron spectroscopy established that coordination of the metal ions had occurred. For cobalt, evidence of coordination to both ether and amine functions is obtained, but for the other metal ions evidence of ether coordination is less definitive. 

The success of this class of experiment has led to much interest in novel types of magnetic semiconductor, and the most interesting recent discovery in this domain is that zinc oxide is such a candidate when doped with small percentages of such metals as cobalt, iron and manganese. It displays a rich phase diagram whose details have yet to be fully explored and its very major attraction is the ease with which it may be made in thin film form and this procedure integrated into device fabrication routines. 

Naphthenate Driers n Compounds of naphthenic acid with metals, usually lead, cobalt, or manganese used to accelerate the oxidation of the ink film. 

The incidence of false positive results was not reported in the Dewberry Davis study. However, several elements sometimes found in paint films can be expected to contribute to false positive results if present in sufficient concentrations and suitable chemical form these include copper, cobalt, mercury, manganese, and iron. Vind et al. (1976) reported that positive responses were not obtained under typical testing conditions for iron oxide pigments. In contrast, they found that neat biocides (containing mercury or copper) and driers (containing cobalt or manganese) did turn black in the presence of sulfide ions. However, they concluded that given the usually low concentrations of these materials in paints, interference due to these elements would be minimal. 

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