Antimony intermetallic compounds

The phase diagram for the copper-antimony system is shown on the next page. The phase diagram contains the intermetallic compound marked "X" on the diagram. Determine the chemical formula of this compound. The atomic weights of copper and antimony are 63.54 and 121.75 respectively. 

Of the elements normally present in tin-rich alloys, lead forms a simple eutectic system with a eutectic composition at 63% Sn, and copper and antimony have a small solid solubility and form the intermetallic compounds Cu Sn, and SbSn respectively. ... 

Many alloys possess properties that would hardly be predicted from the known properties of the constituent components. For example, some of these alloys are magnetic, though neither of the components is markedly so (Heussler alloys). An example is the manganese-antimony alloy (intermetallic compound). 

The most commonly measured property for these types of molecules is their dissociation energy or atomization energy. According to a recent review ( ) these have been experimentally determined for approximately 50 homonuclear diatomic metal molecules, 15 polyatomic metal molecules (including germanium but excluding silicon and antimony), 110 diatomic intermetallic compounds and more than 20 polyatomic intermetallic molecules. 

Group 15 (Sb, Bi). Antimony reacts sluggishly, and no compounds are formed. With bismuth there is no corrosion of tungsten at 1000°C, and no intermetallic compound is formed. 

Two new effects are, however, encountered. Thus, there is extremely restricted solid solubility of univalent silver in divalent magnesium, while the alloys of magnesium with tin and antimony are of entirely different types, and are. indeed, characterised by the presence of stable intermetallic compounds. The latter observation suggests that one of the causes of the formation of stable intermetallic compounds ride p. 85) is the presence, in an alloy, of a strongly electropositive metal, for example, magnesium, and an electron-deficient metal, like antimony. 

When several metals are simultaneously electrodeposited in mercury, intermetallic compounds between them may be formed. In anodic stripping voltammetry the following compounds of copper, zinc, and antimony may influence the measurements CuZn, CuSn, CuGa, SbZn, SbCd, and Sbln. The values of their solubility products are between 2 x 10 (SbZn) and 4 x 10 (CuZn) [1]. 

Removal of silver using zinc must follow copper removal and softening . Copper forms intermetallic compounds with zinc, as does arsenic and tellurium. The presence of antimony and tin also affects the performance of the desilverising operation, in particular separation of the silver-zinc alloy phase. 

In practice the mass ratio of magnesium to calcium used is between 2 1 and 4 1, and depends on the relative cost of the reagent metals. The process is promoted by the addition of antimony, which can also form intermetallic compounds as a replacement for bismuth, and is necessary to achieve low levels of residual bismuth. It is suggested that the antimony compound is isomorphous with the bismuth compound and a solution of the two causes a lowering of the activity of the bismuth complex (Moodie, 1976). 

The antimony-cadmium alloy is used under the name MFX alloy exclusively by GNB (now Exide) for the Absolyte Battery. It contains 1.5% antimony and 1.5% cadmium. With this alloy, cycling is possible owing to the antimony content. On the other hand, antimony release is rather low because the intermetallic compound SbCd is formed between antimony and cadmium that keeps antimony within the positive plate. A disadvantage of this alloy is its high cadmium content, because of the toxicity of cadmium. This does not concern the battery, but might cause problems for remelting of these batteries when they are recycled after service. 

Intermetallic compounds with antimony and bismuth will be considered in sections 4 and 5, because of their close structural similarity to compounds with the non-metals of group Va. 

Although intermetallic compounds have been considered in sect. 3 of this review, compounds with the metallic elements antimony and bismuth will be included in the following sections, because their structural properties are similar to those of compounds with the other Va elements N, P, and As. 

In some regions, a widely used lead alloy is lead antimony cadmium. Antimony and cadmium will react to form an intermetallic compound SbCd. During charge, the positive grid undergoes corrosion and produces antimony in the corrosion layer. 

Dispersed intermetallic compounds such as Ag3Sn in eutectic Sn-Ag solder and SbSn in tin-antimony solders increase the strength and creep resistance of the solder, but the alloys are quite ductile as subsequently discussed. The interface between these intermetallic compounds and the tin-based solid solution is not a source of brittle fracture. 

Stibine. Sbl h, is formed by hydrolysis of some metal antimonides or reduction (with hydrogen produced by addition of zinc and HC1) of antimony compounds, as in the Gutzeit test. It is decomposed by aqueous bases, in contrast with arsine. It reacts with metals at higher temperatures to give the antimonides. The antimonides of elements of group la. 2a, and 3a usually are stoichiometric, with antimony trivalent. With other metals, the binary compounds are essentially intermetallic. with such exceptions as the nickel series, Ni. Sb.. NiSb, Ni5Sb2 and Ni4Sb. 

The intermetallic phase /3-SbSn has the rock-salt structure with one lattice almost exclusively occupied by antimony and the other by tin. Write the Gibbs energy expression using the compound energy model for a ternary phase including bismuth, where it is assumed that Bi goes preferentially into the mostly Sb sublattice. 

In order to provide the required flame retardancy to the molding compound, an encapsulated formulation usually contains brominated resins and antimony oxide. The brominated resins used in the encapsulated formulation are mainly tetrabromobisphenol A (TBBA) based epoxy resin or brominated epoxy novolac. These bromine-containing additives were reported to cause bond degradation at high temperature through accelerated void formation in the gold-aluminum intermetallic phases (1-4). 

An antimony containing intermetallic alloy compound consisting of molybdenum and antimony dispersed in an amorphous carbon matrix was developed using a high-energy mechanical milling technique (119). This material was used as the anode for a sodium-ion battery... 

---