Cadmium oxide properties

A third group includes silver—nickel, silver—cadmium oxide, and silver—graphite combinations. These materials are characterized by low contact resistance, some resistance to arc erosion, and excellent non sticking characteristics. They can be considered intermediate in overall properties between silver alloys and silver or copper—refractory compositions. Silver—cadmium oxide compositions, the most popular of this class, have wide appHcation in aircraft relays, motor controllers, and line starters and controls. 

Many organocadmium compounds are known but few have been of commercial importance. Wanklyn first isolated diethyl cadmium in 1856. The properties of this and other dialkylcadmiums are listed in Table 4. In general, these materials are prepared by reaction of an anhydrous cadmium halide with a Grignard or alkyUithium reagent followed by distillation of the volatile material in an inert atmosphere or in vacuo. Only the liquid dimethyl compound is reasonably stable and then only when stored in a sealed tube. Dimethylcadmium is mildly pyrophoric in air and produces dense clouds of white, then brown, cadmium oxide smoke, which is highly toxic if breathed (45). When dropped into water, the liquid sinks in large droplets that decompose with a series of small explosive jerks and pops. For this reason, and particularly because of the low thermal stability, most dialkylcadmium materials are prepared and used in situ without separation, eg, in the conversion of acid chlorides to speciality ketones (qv) ... 

Production. The raw material for the production of cadmium yellow pigments is high-purity cadmium metal (99.99 %), cadmium oxide, or cadmium carbonate. If the metal is used it is first dissolved in mineral acid. A zinc salt is then added to the solution the amount added depends on the desired shade. The zinc salt is followed by addition of sodium sulfide solution. An extremely finely divided cadmium sulfide or cadmium zinc sulfide precipitate is formed, which does not possess any pigment properties. This intermediate product can also be obtained by mixing the cadmium or cadmium-zinc salt solution with sodium carbonate solution. An alkaline cadmium carbonate or cadmium zinc carbonate precipitate is formed which reacts in suspension with added sodium sulfide solution. 

Replacing zinc with cadmium produces a cell with an OCV of 0.90 V, with characteristics very similar to those of the zinc-mercuric oxide system described above, but which is able to be stored and operated at extreme temperatures (—55 to 80°C) due to the low solubility of cadmium oxide even in concentrated KOH. Cells have been successfully operated at 180°C. Note that hydrogen generation does not occur at a cadmium anode. Because of cost and disposal problems, such cells are used only for applications where their special properties can be exploited, e.g. telemetry from internal combustion, jet or rocket engines. 

Table 8 Physical properties of cadmium oxide, peroxide and hydroxide...

Transparent conductive coatings combine high optical transmission with good electrical conductivity. The existence of both properties in the same material is, from the physics point of view, not trivial and is only possible with certain semi-conductors like indium oxide, tin oxide, cadmium oxide, and with thin gold and silver films, e.g. [157]. Particularly antimony or fluorine doped tin oxide (ATO, FTO), tin doped indium oxide (ITO), and aluminium, indium, or boron doped zinc oxide (AZO, IZO, BZO) are of technical importance [157a]. 

PHYSICAL PROPERTIES soft, silver-white metal usually found in combination with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfide) malleable or powder becomes brittle at 80 °C MP (321°C) BP (765°C) DN (8.642) VP (negligible 25 C) solubility in water (CdCl2 1.4x10 mg/L 20°C, Cd(OH)2 2.6 25°C mg/L) refractive index (1.13)... 

CHEMICAL PROPERTIES combustible tarnishes in moist air slowly oxidized by moist air to form cadmium oxide highly corrosion resistant corrosion resistance poor in industrial atmospheres lowers melting point of certain alloys when used in low percentages resistant to alkalies reacts vigorously with strong oxidizers, elemental sulfur, selenium and tellurium. 

In the first class of CPs nanocomposites, the oxides considered as secondary component are titanium dioxide (TiO ), zirconium dioxide (ZrOj), silicon dioxide (SiO ), aluminium oxide (Al O ), cadmium oxide (CdO) and zinc oxide (ZnO) [19, 27, 31, 48-52]. Titanium dioxide nanoparticles have excellent properties such as charge carrier, oxidising power, non-toxicity, chemical and photo stability. Conductive PANI/TiO nanocomposites combine the qualities of PANI and nanocrystalline TiO within a single material, thereby developing multifunctional materials with combined properties which have very strong potential applications. 

Elemental cadmium is a silver-white, blue-tinged, lustrous metal which is easily cut with a knife. It is slowly oxidized by moist air to form cadmium oxide. It is insoluble in water, but reacts readily with dilute nitric acid. Some of the physical properties and other descriptive information of elemental cadmium are given below ... 

Zinc oxide is the major vulcanization agent required for Thiokol FA however, the particular grade is important as certain impurities may affect the cure rate and final properties. A French process zinc oxide, such as Midwest AZO 66L or equivalent, is recommended. Other oxides such as lead oxide or dioxide, cadmium oxide, and zinc hydroxide may also be used with varying rates of cure and physical properties. The amount of zinc oxide over or under 10 phr is not critical and will not affect the rate of vulcanization. Note that the MBTS and DPG are peptizing agents, not accelerators. 

The metal oxide solubilities in the chloride-bromide sequence were shown in our papers to considerably decrease. For example, strontium oxide, which is referred to as moderately soluble in low-acidic chloride melts, becomes slightly soluble in the bromide melt. Calcium and cadmium oxides slightly soluble in chloride melts become practically insoluble in molten bromides. The basic properties of BaO in the bromide melt essentially weaken, and degree of its dissociation, in the saturated solution in molten bromide, considerably diminishes. 

Lead—tin (1.8—2.5 wt %) is used both as a cable sheathing ahoy (BS 801 ahoy A and DIN 17640) and as a battery connector ahoy ia sealed lead—calcium—tin batteries (15). Tia is generahy added to lead—arsenic cable ahoys ia smah amounts. The arsenic ahoys have excehent creep resistance and mechanical properties, but are unstable and lose arsenic readily by oxidation. The addition of smah amounts of tin (0.10—0.20 wt %) eliminates arsenic loss. Lead ahoys having 0.4 wt % tin and 0.15 % cadmium, which are used for cable sheathing, do not age harden, show excehent corrosion and creep resistance, and are very ductile. 

Heterogeneous Photocatalysis. Heterogeneous photocatalysis is a technology based on the irradiation of a semiconductor (SC) photocatalyst, for example, titanium dioxide [13463-67-7] Ti02, zinc oxide [1314-13-2] ZnO, or cadmium sulfide [1306-23-6] CdS. Semiconductor materials have electrical conductivity properties between those of metals and insulators, and have narrow energy gaps (band gap) between the filled valence band and the conduction band (see Electronic materials Semiconductors). 

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