Alloys containing indium

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. 

Other lead-free solder alloys which have been developed and evaluated by fee industry include Sn-Ag, Sn-Ag-Bi, Sn-Bi-In, and other ternary and quaternary alloys (Ref 24-33). The use of alloys containing indium (In) may be limited due to fee scarcity of indium and its high cost. The eutectic Sn-Ag alloy (melting temperature 221 °C, or 429 °F) was qualified for automotive applications in fee 1990s on ceramic thick film substrates and PWBs (Ref 3,12-15,34- 5). The microstructural characteristics of the Sn-Ag-Cu system under different reflow conditions and... 

The Al-Zn-Sn alloys require careful heat treatment in their production. Inevitably this leads to more expense and inconvenience. The advent of the alloys containing mercury or indium rendered these alloys very much less attractive. Presently Al-Zn-Hg alloys are under some pressure because... 

The low-melting-point (157 °C), silver metal is mainly used in alloys to decrease the melting point. Combined with tin, lead, and bismuth to produce soldering metal for wide temperature ranges. The element is highly valuable in the electronics age as its unique properties are ideal for solar cells, optoelectronics, and microwave equipment. The arsenide is used in lasers and is also suitable for transistors. ITO (indium tin oxide) is a transparent semiconductor with wide application in displays, touchscreens, etc. In the household, indium as an additive prevents the tarnishing of silverware. Some electronic wristwatches contain indium batteries. 

An important use of indium is in making coatings. For example, some aircraft parts are made of alloys that contain indium. The indium prevents them from wearing out or reacting with oxygen in the air. 

Taking into account the dissolution potential of aluminium, anodes can be made either in zinc or in a special aluminium alloy called Hydral , which contains indium (0.015-0.025%) or tin (0.10-0.20%). Magnesium anodes must not be used, because they lower the potential too much and will thus lead to severe cathodic corrosion of aluminium. 

Solders are typically classified as either soft or hard. Some confusion often results from this convention because some hard solders are really braze materials if the melting temperature criterion is applied. Soft solders typically consist of alloys containing lead and tin, but also often contain indium (In), bismuth (Bi), antimony (Sb), or silver (Ag). In practice, most soft alloys melt at temperatures lower than 450°C, usually between 180°C and 300°C. High-tin solders, typical of lead-free solders, tend to be stiffer, harder, and less ductile compared to high-lead solders. Hard solders often contain metals such as Au, Zn, Al, and Si. 

There is some uncertainty as to whether zinc embrittles aluminum. However, indium severely embrittles aluminum. Alkali metals, sodium, and lidiium also are known to embrittle aluminum. Aluminum alloys containing either lead, cadmium, or bismuth inclusions embrittle when impact-tested near the melting point of these inclusions the sevoity of embrittlement increases from lead to cadmium to bismuth. 

Platiaum and its alloys are also used as biomedical electrodes, eg, platiaum—indium wires for permanent and temporary pacemaker leads and defibrillator leads. Electrophysiology catheters, which contain platinum electrodes and marker bands, have been used to map the electrical pathways of the heart so that appropriate treatment, such as a pacemaker, can be prescribed. 

Soldered joints present their own characteristic corrosion problems usually in the form of dissimilar metal attack often aided by inadequate flux removal after soldering. Such joints have always been a source of concern to the electrical industry. Lead-containing solders must be used with caution for some types of electrical connection since PbfOHjj.PbCOj may be found as a corrosion product and can interrupt current flow. Indium has been found to be a useful addition to Sn-Pb solders to improve their corrosion resistanceHowever, in view of the toxicity of lead and its alloys, the use of lead solders, particularly in contact with potable waters and foodstuff s, is likely to decline. 

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. 

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 ). 

The supplanting of germanium-based semiconductor devices by silicon devices has almost eliminated the use of indium in the related alloy junction (see Semiconductors). Indium, however, is finding increased use in III—V compound semiconductors such as indium phosphide [22398-80-7] for laser diodes used in fiber optic communication systems (see Electronic materials Fiber optics Light generation). Other important indium-containing semiconductors include indium arsenide [1303-11-3], indium antimonide [1312 -1-0], and copper—indium—diselenide [12018-95-0]. 

In the case of so-called active soldering an active solder is used a metallic solder containing interface active additives which make certain that the molten solder wets the ceramics. An example of such a solder is a silver / copper alloy with a titanium or titanium / indium additive which can be used when soldering zirconium (IV) oxide to certain steels, aluminium oxide to nickel / cobalt or iron / nickel alloys and aluminium oxide to a iron / nickel / cobalt alloy. 

The electrodeposition of antimony [77] and indium-antimony [78] alloys has been reported in a basic EMICI-EMIBF4 ionic liquid. Antimony trichloride, SbCl3, dissolves in the ionic liquid and forms SbQ, the same as in the basic chloro-aluminate ionic liquid. Metallic Sb can be obtained by the cathodic reduction of SbCl4, as shown in Eq. (9.14). The formal potential of Sb(III)/Sb is reported as —0.27 V vs. AI/Al(in) in the ionic liquid containing Cl at 0.11 M. In addition the oxidation of SbCl4 leads to the formation of a pentavalent antimony species, SbClg ... 

The classical electronics solder alloy (Sn + 37 wt% Pb) contains the inhalation-toxic element lead and is being replaced in electronics for health reasons. A Pb-free solder is Sn-3.5wt% Ag indium and bismuth alloys are other eutectic-forming alloying additives to Sn. The classical brazing alloy is at the Cu-Ag eutectic (Ag-F 28.1 w% Cu) and is well suited for mechanically strong contacts with Cu and its alloys. 

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