Antimony containing lead alloys

In the literature, numerous lead alloys containing almost all other elements of the periodic table have been tested in an effort to meet the miscellaneous requirements of the lead-acid battery industry [3]. Among those alloys explored, the most widely used ones are antimony-containing lead alloys. 

Automobile battery grids employ about 1—3 wt % antimony—lead alloys. Hybrid batteries use low (1.6—2.5 wt %) alloys for the positive grids and nonantimony alloys for the negative grids to give reduced or no water loss. The posts and straps of virtually all lead—acid batteries are made of alloys containing about 3 wt % antimony. 

Excellent antifriction properties and good hardness (qv) make lead—antimony—tin alloys suitable for journal bearings. The alloys contain 9—15 wt % antimony and 1—20 wt % tin and may also contain copper and arsenic, which improve compression, fatigue, and creep strength important in bearings. Lead—antimony—tin bearing alloys are Hsted in ASTM B23-92 (7). 

Low (2—5 wt %) antimony, low (2—5 wt %) tin lead alloys are used for automobde body solder. Special lead—antimony alloys containing 1—4 wt % antimony are used for wheel-balancing weights, battery cable clamps, collapsible tubes, and highly machined isotope pots. 

Wrought lead—calcium—tin alloys contain more tin, have higher mechanical strength, exhibit greater stabiUty, and are more creep resistant than the cast alloys. RoUed lead—calcium—tin alloy strip is used to produce automotive battery grids in a continuous process (13). Table 5 Hsts the mechanical properties of roUed lead—calcium—tin alloys, compared with lead—copper and roUed lead—antimony (6 wt %) alloys. 

Sodium—lead alloys that contain other metals, eg, the alkaline-earth metals, are hard even at high temperatures, and are thus suitable as beating metals. Tempered lead, for example, is a beating alloy that contains 1.3 wt % sodium, 0.12 wt % antimony, 0.08 wt % tin, and the remainder lead. The German BahnmetaH, which was used ia axle beatings on railroad engines and cars, contains 0.6 wt % sodium, 0.04 wt % lithium, 0.6 wt % calcium, and the remainder lead, and has a Brinell hardness of 34 (see Bearing MATERIALS). 

Lead Alloys. A teUurium—lead aUoy containing 0.02—0.1% teUurium, with or without antimony, was introduced in 1934 (81) as teUurium lead or Teledium. This aUoy has higher recrysta11i2ation temperatures and corrosion resistance and takes a significantly longer time to soften at 25°C after cold work. 

Antimony Alloys. Approximately one-half of the total antimony demand is for metal used in antimony alloys. Antimonial lead is a term used to describe lead alloys containing antimony in proportions of up to 25%. Most commercial lead—antimony alloys have antimony contents less than 11%. The compositions of several important antimony alloys are given in Table 4. 

Demand for high performance SLI batteries has led to the development of smaller, lighter batteries that require less maintenance. The level of antimony is being decreased from the conventional 3—5% to 1.75—2.75% to minimise the detrimental effects. Lead alloys that contain no antimony have also been introduced. Hybrid batteries use a low antimony—lead alloy in the positive plate and a calcium—lead alloy in the negative plate. 

Many of uses of tin are also those of lead, because the metals form useful alloys. When lead is alloyed with a few percent of tin, it becomes harder and more durable. Although other compositions are produced, common solder consists of about an equal mixture of tin and lead. An alloy known as type metal contains about 82% Pb, 15% Sb, and 3% Sn, and pewter contains approximately 90% tin that is alloyed with copper and antimony. Babbitt, an alloy used in making bearings, contains 90% Sn, 7% Sb, and 3% Cu. Tin is also used to coat other metal objects to retard corrosion, and a tin-niobium alloy is used in superconducting magnets. 

Many tin alloys containing lead, copper, antimony, and bismuth were also in use in Marggrafs time. He mentioned three kinds of unalloyed tin first the Malaga, reputed to be the best, second the English, and third the Saxon and Bohemian (219). 

Type-metal is an alloy of lead and antimony, containing 18 per cent of the latter. It expands slightly on solidifying, and consequently when cast in the mould it takes an accurate impression and forms a clean-cut type. 

The pellets are sometimes graphite coated, copper plated, or nickel plated. Plated shot is normally confined to hard or extra hard shot. The alloying metal is usually antimony, and lead pellets typically contain between 0% and 6% antimony, although up to 12% antimony has been encountered. Tungsten-polymer shot is also manufactured and, as the name implies, contains tungsten metal embedded in some sort of thermoplastic. 

Lead alloys containing antimony in the range 1-17 % have the applications noted below ... 

The grid metallics should be stored and recovered separately from the battery paste so that metals from the alloys in the battery grids do not contaminate the relatively pure lead paste, which is ideal for producing soft lead. Alloys used to manufacture VRLA batteries do not contain either antimony or arsenic, and this means that the potential hazard of stibine (antimony hydride, SbHs) and arsine (arsenic hydride, AsHs) formation during the storage of the metallics is removed. Many automotive batteries with antimonial and arsenical alloys are still in use. 

Hardened with a little antimony it is used in storage batteries or accumulators, for cables, and occasionally for statuary. For this last, however, it is not really suitable its dull colour is not prepossessing. Bullets, etc, are made of lead hardened with 4 to 12 per cent of antimony. Other important alloys are solder (p. 212), type metal (p. 197) and bearing metals, which contain also tin and antimony. 

Tin and noble metals are not affected by sodium in lead alloys (43), Penaroya (66) foimd that sodium can be used to help remove zinc after the desilverization of lead and that a dross, containing the copper together with antimony and arsenic, can be formed when sodium is introduced into lead bullion. The noble metals are not affected in the absence of zinc. 

Lead alloy anodes, containing 2% silver, or 1 % silver and 5 % antimony, are used for CP systems in seawater. Lead alloy anode should not be buried in the sea bottom or used in freshwater applications. 

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