Gallium Metal and Its Alloys

Antimony alloys have many commercial applications. The metal makes its alloys hard and stiff and imparts resistance to corrosion. Such alloys are used in battery grids and parts, tank linings, pipes and pumps. The lead plates in the lead storage batteries constitute 94% lead and 6% antimony. Babbit metal, an alloy of antimony, tin, and copper is used to make antifriction machine bearings. Alloys made from very high purity grade antimony with indium, gallium and bismuth are used as infrared detectors, diodes, hall effect devices and thermoelectric coolers. 

Because bismuth expands on solidification and because it alloys with certain other metals to give low melting point alloys, bismuth is particularly weU suited for a number of uses. Alloys of bismuth can be made that expand, shrink, or remain dimensionally stable on solidification. AH other metals except gallium and antimony contract on solidification. Bismuth aHoys and uses are summarized in Table 5. 

A liquid metal alloy [36] containing gallium, indium, and tin has been proposed as an additive to Portland cement. A formulation is shown in Table 18-10. The liquid metal alloy has a melting point of 11° C. Its presence does not cause corrosion of stainless steel up to 250° C but causes corrosion of steel alloys at temperature above 35° C, and it dissolves aluminum at room temperature. The alloy is harmless to skin and mucous membranes. 

Metals easily form alloys with other metals. The presence of even a small amount of another element in a metal severely affects its properties, as in the case of carbon in iron. Mercury, cesium, and gallium exist as liquids at room temperature. 

It does not decompose water, even at the boiling temperature. At low temperatures it is stable in the air, but when heated it I >urns with a blue flame, producing ln203. The heat of combustion is 1044.6 calories per gram of metal. It unites directly with, the halogens and with sulfur. It dissolves in mineral stends, but not in KOH solution. In the electromotive series i t falls between iron and lead. It forms alloys with lead, thal-lium, tin, gold, platinum, gallium, mercury, and sodium. 

Aluminum, Aluminium. Al at. wt 26.98154 at. no. 13 valence 3. One naturally occurring isotope nAI. In addition, six radioactive isotopes and one isomer are known the most important, MAI (found in meteors), decays with emission of 0+ and >-radiation. Tw 7.4 X 10s years. One of the most abundant metals in earth s crust 8.8 % by wt occurs in nature primarily in combination with silica, also as oxide (see Aluminum Silicate Aluminum Oxide). First obtained in impure form by Oersted in 1825 prepd as metal powder by Wohler in 1827. Reviews of aluminum, its alloys and compds Brandt. Aluminum and Aluminum Alloys" in Prac. Met. Soc. Conf. Vol. 40. E. D. Verink, Ed. (Gordon Breach, New York, 1966) Aluminum. 3 Vols, K. R. Van Horn, Ed. (American Society for Metals, Metal Park, Ohio. 1967) Wade, Bannister. "Aluminum, Gallium. Indium and Thallium in Comprehensive Inorganic Chemistry, Vol, 1, J. C. Bailar, Jr. et al.. Eds. (Pergamon Press, Oxford, 1973) pp 993-1064. 

For the application of this equation one has to measure surface energy (surface tension) and its dependence on electrode potential at constant activities of the different components. Precise measurements are restricted to liquid metals like mercury or gallium and their alloys. Classical experiments were made with the Lippmann electrocapillary meter. The measurement of the drop time or the drop frequency of a dropping mercury electrode is easier. 

Arsenic is an element with the symbol As and the atomic number 33. It can occur as a pure element but is most often found in minerals containing sulfur and metals. Arsenic can exist in different structural forms (allotropes). However, gray arsenic is the most common. It is a metalloid that is brittle and a bit shiny. See Fig. 5 [25]. This form has metallic properties and has been used in industry to strengthen alloys of copper and lead. Arsenic is also a common n-type dopant in semiconductor electronic devices (example gallium arsenide is a semiconductor). Over the years arsenic and its compounds were used in the production of products like pesticides, insecticides, and treated wood items. However, because of its toxicity and harmful effects to humans, arsenic s applications have decreased. 

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