Alloys containing gallium

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. 

R. A. Allakhverdiev, B. Khydyrkuliev, and N. V. Reznikov. Plugging solution for repairing oil and gas wells-contains plugging Portland cement, isobutanol, water and liquid metal alloy of gallium, indium and tin, to increase strength of cement stone. Patent SU 1802082-A, 1993. 

A1 will leave the grains to enter the grain boundaries, and w ill also in turn diffuse towards a reaction site, allowing the process to repeat itself until most or all of the Al has been consumed by the reaction. This theory is consistent with the observation that alloys made without In and Sn will not react at room temperatures. Ga without In and Sn remains solid at room temperature, and thus any alloy with solid gallium in its grain boundaries would not be able to provide a pathway to a reaction site for any ot the Al the alloy contains. 

An alloy consisting of 24% indium and 76% gallium is liquid at room temperature. Low-melting tin-bismuth alloys contain indium. They are used for safety fuses, in fire-alarm boxes and in sprinkler systems. Also indium alloys are used as solders for printed circuit boards. Indium alloys are easily composed for a specified melting range. Alloys of this type are used to give a signal dear for the Christmas ham or turkey to be taken out from the oven. 

During an investigation of the temperature dependence of the rate of hydrogen evolution at a liquid mercury-gallium alloy (containing 2.1 at. % Hg), very high values of the preexponential factor were observed in acidic as well as alkaline solutions. At least in acidic solutions, the experimental value (log k = 7.6) exceeded any reasonable theoretical estimates of the upper limits of the preexponential factor by several orders of magnitude[262]. Hence, it was naturally assumed that the experimental value was considerably distorted due to the dependence of the composition of the alloy surface on temperature. This assumption was verified with the help of the kinetic isotope effect. 

The high value of the preexponential factor may be explained by a considerable change in the properties of the surface layer with temperature. An alloy containing 2.1 at.% Hg is nearly saturated at room temperature, while at a temperature of about 80°C, the solubility of mercury increases about 1.5 times[403]. Consequently, at increased temperatures, the alloy is far from saturation. We can therefore expect a lower surface concentration for mercury and higher for gallium. The enrichment of the surface by a metal with a lower overpotential increases (in absolute magnitude) the temperature coefficient of the overpotential, i.e. increases the activation energy and the preexponential factor. 

Notes on cluster phases in triel alloys. Li and Corbett (2004) have shortly reviewed the systematic and extensive experimental and theoretical work carried out by Corbett and co-workers (see for instance Corbett 1996). Considering alkali metal-triel alloys, they underlined, particularly for Ga, In and Tl, the richness of their chemistry (see also 5.3.4.4). Gallium forms many anionic network structures (and only a few phases containing isolated cluster units), indium gives several examples of both network and discrete cluster structures, thallium forms especially discrete clusters (Tl , T157A Tl , Tl , Tl(f, Tl ). 

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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