Bismuth-tellurium alloy

The Plasmadust process is suitable for a wide variety of materials, and this opens up tremendous potential. The prerequisites are that the material has to be available in powder form and it has to melt inside the temperature window of the Plasmadust process. Along with the mainstream metals (copper, aluminum, gold, tin, bismuth, tellurium) and polymers (PTFE, PE, ABS, PP), glass, ceramic materials, semiconductors such as GIGS (copper, indium, gallium, sulfur, selenium), and even minerals like salt can be deposited on substrates such as metal, plastic, glass, ceramic, paper, card, and textiles. Another advantage is that the process can also handle alloys and material combinations such as carbon and metal [42,139,140,179). 

Of the elements commonly found in lead alloys, zinc and bismuth aggravate corrosion in most circumstances, while additions of copper, tellurium, antimony, nickel, silver, tin, arsenic and calcium may reduce corrosion resistance only slightly, or even improve it depending on the service conditions. Alloying elements that are of increasing importance are calcium especially in maintenance-free battery alloys and selenium, or sulphur combined with copper as nucleants in low antimony battery alloys. Other elements of interest are indium in anodesaluminium in batteries and selenium in chemical lead as a grain refiner ". 

Betts Electrolytic Process. The Betts process starts with lead bullion, which may carry tin, silver, gold, bismuth, copper, antimony, arsenic, selenium, tellurium, and other impurities, but should contain at least 90% lead (6,7). If more than 0.01% tin is present, it is usually removed from the bullion first by means of a tin-drossing operation (see Tin AND TIN alloys, detinning). The lead bullion is cast as plates or anodes, and numerous anodes are set in parallel in each electrolytic cell. Between the anodes, thin sheets of pure lead are hung from conductor bars to form the cathodes. Several cells are connected in series. 

Refining. The alloy of bismuth and lead from the separation procedures is treated with molten caustic soda to remove traces of such acidic elements as arsenic and tellurium (4). It is then subjected to the Parkes desilverization process to remove the silver and gold present. This process is also used to remove these elements from lead. 

Welcher et al. [ 10] have described the direct determination of trace quantities of lead, bismuth, selenium, tellurium and thallium in high-temperature nickel alloys using electrothermal atomisation. 

Welz, B. Melcher, M. Determination of antimony, arsenic, bismuth, selenium, tellurium and tin in metallurgical samples using the hydride atomic absorption technique. 1. Analysis of low alloy steels. Spectrochim. Acta B 1981, 36, 439-462. 

Bismuth telluride with the stoichiometric composition ratio (Bi TCj) is electronically neutral. However, the common carrier of the bismuth telluride alloy can be modified by adjusting the percentage of tellurium or bismuth incorporated. If the alloy is tellu-ride-rich, it can be n-type. In order to be p-type, the composition of the bismuth telluride alloy should be bismuth-rich instead of telluride-rich [59]. This is advantageous since the material deposition development can focus on a single material system which will yield both the n- and p-branches of the thermoelectric probes. 

General.—Liquid bismuth has been used as the solvent for calorimetry and data for the enthalpy of solution of copper, indium, and tellurium have been obtained. Enthalpy of formation data are also given for a series of copper selenides. Studies on the distribution of lithium and bismuth between liquid Li-Bi alloys and molten LiCl suggested that a salt-like species LijBi was being selectively dissolved from the alloys. The mutual solubility of thorium and the metallic lanthanides La, Nd, and Eu in bismuth over the range 350—700 °C shows evidence for the formation of solid compounds with the composition ThLnBij,. ... 

Gold-silver-copper alloys are frequently used in coinage and gold wares. A purple alloy results with 80% Au and 20% aluminum, but this compound is too brittle to be made into jewelry. Gold forms alloys with many other metals, but most of these are also brittle. As little as 0.02% of tellurium, bismuth, or lead makes gold brittle. 

Established thermoelectric materials conveniently fall into three groupings with each dependent upon the temperature range of operation (Figure 3). Alloys based on bismuth in combinations with antimony, tellurium or selenium are referred to as low temperature materials and can be used at... 

To be classified as a copper, an alloy must contain a minimum of 99.3% copper. Elements such as silver, arsenic, lead, phosphorus, antimony, tellurium, nickel, cadmium, sulfur, zirconium, manganese, boron, and bismuth may be present, singly or in combination. Because of the good electrical properties of copper, it is used primarily in electrical or electronic applications such as bus bars, waveguides, wires, switches, and transfer components. Because copper is a noble metal, it also finds many applications in corrosive environments. Table 18.4 gives the chemical composition of some of the coppers used in corrosion applications. 

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