Indium fusible alloy

Alloys are mixtures of metals combined to obtain specific characteristics and enhanced properties for a particular application. The term fusible metals or fusible alloys denotes a group of alloys that have melting points below that of tin (232°C, 449°F). Most of these substances are mixtures of metals that by themselves have relatively low melting points, such as tin, bismuth (m.p. 275°C), indium (157°C),... 

Ref 1), The term is generally applied to alloys melting below 450°F(233°C). They can be binary, ternary, quaternary, or quinary mixts of Bi, Pb, Sn, Cd, Indium and less frequently other metals. Eutectic alloys are relatively few in number and are the particular compns that have definite and minimum mp as compared with other mixts of the same metals. Table I of Ref 2 lists 17 eutectics of mp s ranging from 46.89° to 248.0°C. Of these the Lipowitz s eutectic, melting at 70.0° is well known. It consists of Bt 50, -Pb 27, Sn 13 Cd 10%. Table II of Ref 2 lists 13 non-eu ectic alloys with mp s ranging from 64.0 to 1J9°C. Table III of Ref 2 lists eight common fusible alloys of mp s 70 to 138°. Of... 

The solder and alloy market, including low melting or fusible alloys, is a principal user of indium (see Solders AND BRAZING alloys). The addition of indium results in unique properties of solders such as improved corrosion and fatigue resistance, increased hardness, and compatibility with gold substrates. To facilitate use in various applications, indium and its alloys can be easily fabricated into wire, ribbon, foil, spheres, preforms, solder paste, and powder. 

Indium Symbol In. A soft silvery element belonging to group 13 (formerly IIIB) of the periodic table a.n. 49 r.a.m. 114.82 r.d. 7.31 (20°C) m.p. 156.6°C b.p. 2080 2°C. It occurs in zinc blende and some iron ores and is obtained from zinc flue dust in total quantities of about 40 tonnes per annum. Naturally occurring indium consists of 4.23% indium-1 13 (stable) and 95.77% indium-115 (half-life 6x10 years). There are a further five short-lived radioisotopes. The uses of the metal are small - some special-purpose electroplates and some special fusible alloys. Several semiconductor compounds are used, such as InAs, InP, and InSb. With only three electrons in its valency shell, indium is an electron acceptor and is used to dope pure germanium and silicon it forms stable in-dium(I), indium(II), and indium(III) compounds. The element was discovered in 1863 by Ferdinand Reich (1799-1882) and Hieronymus Richter (1824-90). 

Because of its low melting point, extreme softness and ductility, and excellent wetting characteristics, indium has been widely used as an alloying element for many low-temperature solders and fusible alloys [53,63]. However, because of its high price (several times more expensive than silver), it is not economically feasible to use In-rich alloys for replacing Pb n solders, which are... 

Alloys of Pb—Li are attractive in some nuclear shielding apphcations due to their ability to thermalize neutrons. Lead containing more than 0.5 wt% In wets glass, and Pb—In alloys with up to 5 wt% In can be used for soldering glass over a narrow temperature range. Additions over 25 wt% of In are made to Pb—Sn solders to increase their alkali resistance. An addition of 1 - 2 wt% In in Pb—Ag solders increases their strength. Indium is also used in multi-component fusible aUoy systems. 

The fusible filler is selected from an indium alloy (12). 

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