Lead-antimony alloys silver

Solders -for dental materials [DENTAL MATERIALS] (Vol 7) -for electronic packaging [PACKAGING - ELECTRONIC MATERIALS] (Vol 17) -for gold alloys [GOLD AND GOLD COMPOUNDS] (Vol 12) -lead m [LEAD] (Vol 15) -lead-antimony alloys for [LEAD ALOYS] (Vol 15) -lead-silver alloys [LEAD ALOYS] (Vol 15) -phosphorus compounds m [PHOSPHORUS COMPOUNDS] (Vol 18) -tin compounds m [TIN COMPOUNDS] (Vol 24)... 

In the analysis of high purity metals, trace elements were pre-concentrated by partial dissolution of the matrix. The remaining small part of the matrix retains all trace elements that are electrochemically less noble than the matrix [79,80]. In this way the trace elements were pre-concentrated from silver-, cadmium-, gallium-, indium-, zinc-, lead-, manganese-, aluminium-, and lead-antimony alloys. 

K. Sugitnoto, Y. Sawaka, The effect of some alloying elements on the corrosion resistance of lead-antimony alloys—11. Silver, Corros. Sci. 17 (1977) 415-417. 

Silver reduces the oxygen evolution potential at the anode, which reduces the rate of corrosion and decreases lead contamination of the cathode. Lead—antimony—silver alloy anodes are used for the production of thin copper foil for use in electronics. Lead—silver (2 wt %), lead—silver (1 wt %)—tin (1 wt %), and lead—antimony (6 wt %)—silver (1—2 wt %) alloys ate used as anodes in cathodic protection of steel pipes and stmctures in fresh, brackish, or seawater. The lead dioxide layer is not only conductive, but also resists decomposition in chloride environments. Silver-free alloys rapidly become passivated and scale badly in seawater. Silver is also added to the positive grids of lead—acid batteries in small amounts (0.005—0.05 wt %) to reduce the rate of corrosion. 

Of the elements commonly found in lead alloys, zinc and bismuth aggravate corrosion in most circumstances, while additions of copper, tellurium, antimony, nickel, silver, tin, arsenic and calcium may reduce corrosion resistance only slightly, or even improve it depending on the service conditions. Alloying elements that are of increasing importance are calcium especially in maintenance-free battery alloys and selenium, or sulphur combined with copper as nucleants in low antimony battery alloys. Other elements of interest are indium in anodesaluminium in batteries and selenium in chemical lead as a grain refiner ". 

Lead materials lead-antimony-silver, lead with platinum alloy microelectrodes, lead/magnetite, lead dioxide/titanium, lead dioxide/ graphite. 

Backmank S, Karlsson RW (1979) Determination of lead, bismuth, zinc, silver and antimony in steel and nickel-base alloys by atomic-absorption spectrometry using direct atomization of solid samples in a graphite furnace. Analyst 104 1017-1029. 

Lead-antimony-silver alloy anodes, 74 777 Lead-antimony-tin alloys, 74 771-772 Lead-antimony-tin white bearing alloys, 3 52... 

Lead—tin alloys, 4877 Lead—zirconium alloys, 4878 Lithium—magnesium alloy, 4676 Lithium—tin alloys, 4677 Plutonium bismuthide, 0231 Potassium antimonide, 4668 Potassium—sodium alloy, 4641 Silicon—zirconium alloys, 4904 Silver—aluminium alloy, 0002 Silvered copper, 0003 Sodium germanide, 4412 Sodium—antimony alloy, 4791 Sodium—zinc alloy, 4792 Titanium—zirconium alloys, 4915... 

Highly corrosion-resistant, antimony-free, lead alloys have been used successfully in the positive electrode grids of both single-plate and spiral-wound cells. Spiral-wound cells almost exclusively feature binary lead-tin alloys [36,41] whereas flat-plate electrodes use either lead-calcium alloys, with or without silver additive [26], or lead-tin alloys [48]. Binary lead-tin is known to be highly corrosion-resistant, but rather soft, which is a handicap for plate stacking in prismatic cells. 

CHLORPYRIFOS (2921-88-2) CjHuCljNOjPS Noncombustible solid. Decomposed in water. Incompatible with strong acids, antimony(V) pentafluoride, lead diacetate, magnesiiun, silver nitrate. Hydrolyzed by acid, or alkali solutions. Attacks copper, copper alloys, including brass. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, or CO2 extinguishers. 

Alloys of antimony and aluminium look very much like silver and have been used in the past in forging our coins. One such florin analysed by the author in 1911 contained aluminium 53 40, and antimony 46 38 per cent with traces of lead, arsenic and iron. With copper a violet alloy, probably a compound SbCuj, is formed known as regulus of Venus. Small amounts of antimony are used in stiffening lead. Antimony oxide is used, associated with titanium oxide, as a white pigment, as for example in titanox. 

If the data in Figs 4.12 and 4.14 are juxtaposed, it can be noted that antimony increases the corrosion rate of lead, whereas silver not only neutralises this influence of Sb, but even improves the corrosion resistance of Pb—Sb—Ag alloys. Silver suppresses the inter-granular corrosion and hence overall corrosion is the main process in Pb—Sb—Ag alloys. Silver affects... 

Chromium passivates strongly in acid sulphate media. Hence an inert anode is always employed in chromium plating. It is generally a lead alloy which immediately covers with lead dioxide on positive polarization in the electrolyte. The alloying elements are tin, antimony and silver which are added to the lead to improve its mechanical properties and to reduce the overpotential for oxygen evolution. 

The separation of silver by the Pattinson process used fractional crystallisation, in which molten lead was cooled and partly solidified in a pan while being briskly stirred. The solid lead crystals were relatively pure, leaving silver in the remaining liquid. A row of about nine pans were used, each heated by a fire from below. Crude bullion from the smelter was fed to the middle pan, from which solid crystals were transferred to the first pan on one side and the remaining liquid to the first pan on the other side. This process was repeated from one pan to the next up and down the line to give a purified lead with low silver content at one end and a residual liquid of around 9 kg of silver per tonne at the other end. The silver rich lead was subjected to cupellation to recover a silver bullion. Today, precious metals are separated from lead bullion using the Parkes Process, following the removal of copper, arsenic and antimony. In this process, zinc is added and the lead bulUon is cooled to precipitate a zinc-silver alloy, which is removed and separately treated. 

Many metallic elements are contained in electronic assemblies either as terminations or coatings for component devices or as the electrical circuit, terminations, or coatings on PWBs. The elimination of lead in electronic products requires substitution by other metals that can provide the performance and reliable properties characteristic of traditionally used lead-bearing alloys. There are a number of metal resources that can be selected as substitutes for lead in solders and as coatings for lead-free electronic assemblies. These metals include tin (Sn), silver (Ag), copper (Cu), bismuth (Bi), antimony (Sb), gold (Au), indium (In), nickel (Ni), palladium (Pd), platinum. 

As indicated in the Product Assessment Matrix (Table 5), an environmental assessment of mining metal must consider the energy consumption and the solid, liquid and gaseous residues that result from the various mining processes. Availability of the metals is an additional consideration. Table 6 lists the world reserves of the major metals typically utilized in electronic assemblies. Sn-Ag-Cu alloy is one of the major compositions proposed as a replacement for Sn-Pb solder. Silver is 300 times less available than lead. Half of the silver available comes as a by-product from mining lead, copper and zinc. Antimony and bismuth are also obtained as by-products of lead, copper and silver mining. 

Crude lead contains traces of a number of metals. The desilvering of lead is considered later under silver (Chapter 14). Other metallic impurities are removed by remelting under controlled conditions when arsenic and antimony form a scum of lead(II) arsenate and antimonate on the surface while copper forms an infusible alloy which also takes up any sulphur, and also appears on the surface. The removal of bismuth, a valuable by-product, from lead is accomplished by making the crude lead the anode in an electrolytic bath consisting of a solution of lead in fluorosilicic acid. Gelatin is added so that a smooth coherent deposit of lead is obtained on the pure lead cathode when the current is passed. The impurities here (i.e. all other metals) form a sludge in the electrolytic bath and are not deposited on the cathode. 

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