Alloys containing

Alnico alloys Alloys containing Al, Ni, Co and Fe. Used for permanent magnets. 

It is alloyed with iron, nickel and other metals to make Alnico, an alloy of unusual magnetic strength with many important uses. Stellite alloys, containing cobalt, chromium, and tungsten, are used for high-speed, heavy-duty, high temperature cutting tools, and for dies. 

There is current interest in hydrogen sponge alloys containing lanthanum. These alloys take up to 400 times their own volume of hydrogen gas, and the process is reversible. Every time they take up the gas, heat energy is released therefore these alloys have possibilities in an energy conservation system. 

The amount of iron and manganese in an alloy can be determined by precipitating the metals with 8-hydroxyquinoline, C9H7NO. After weighing the mixed precipitate, the precipitate is dissolved and the amount of 8-hydroxyquinoline determined by another method. In a typical analysis, a 127.3-mg sample of an alloy containing iron, manganese, and other metals was dissolved in acid and... 

The ability to control selectivity by carefully selecting the working electrode s potential, makes controlled-potential coulometry particularly useful for the analysis of alloys. For example, the composition of an alloy containing Ag, Bi, Cd, and Sb... 

A typical m el ter iastalled in a medium sized brass foundry contains 4500 kg of brass and its inductor is rated 500 kilowatts. Brass is an alloy containing copper and zinc. Zinc vaporizes at temperatures weU below the melting temperature of the alloy. The channel iaductor furnace s low bath temperature and relatively cool melt surface result in low metal loss and reduced environmental concerns. Large dmm furnaces have found use in brass and copper continuous casting installations. 

Gold and gold-based alloys ate used for corrosion-resistant equipment. Gold—platinum alloys, 75 Au-25 Pt or 84 Au-15 Pt-1 Rh, ate used as cmcible material for many molten salts (98). Spinnerets for rayon manufacture ate based on the Au—Pt system which exhibits a broad miscibility gap in the soHd state so that the alloys can be age-hardened. Spinneret alloys contain 30—40% or mote platinum modified by small additions of usually rhodium (99). Either gold or gold—platinum alloys ate used in mpture disks for service with corrosive gases (100). 

Tantalum and 2kconium exhibit the highest corrosion resistance to HCl. However, the corrosion resistance of 2ironium is severely impaHed by the presence of ferric or cupric chlorides. Tantalum—molybdenum alloys containing more than 50% tantalum are reported to have exceUent corrosion resistance (see Molybdenumand molybdenum alloys) (69). Pure molybdenum and tungsten are corrosion resistant in hydrochloric acid at room temperature and also in 10% acid at 100°C but not in boiling 20% acid. 

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. 

Anodes. Lead—antimony (6—10 wt %) alloys containing 0.5—1.0 wt % arsenic have been used widely as anodes in copper, nickel, and chromium electrowinning and metal plating processes. Lead—antimony anodes have high strength and develop a corrosion-resistant protective layer of lead dioxide during use. Lead—antimony anodes are resistant to passivation when the current is frequendy intermpted. 

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. 

Lead alloys containing 0.09—0.15 wt % calcium and 0.015—0.03 wt % aluminum are used for the negative battery grids of virtually all lead—acid batteries in the United States and are also used in Japan, Canada, and Europe. If the molten alloy is held at too low a temperature, the aluminum precipitates from solution, rises to the surface of the molten alloy as finely divided aluminum particles, and enters the dross layer atop the melt. 

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. 

Only lead alloys containing copper below 0.08% have practical appHcations. Lead sheet, pipe, cable sheathing, wine, and fabricated products are produced from lead—copper alloys having copper contents near the eutectic composition. Lead—copper alloys in the range 0.03—0.08 wt % copper are covered by many specifications ASTM B29-92 (7), QQL 171 (United States), BS 334, HP2 Type 11 (Canada), DIN 1719 (Germany), and AS 1812 (Austraha). 

Lead—copper alloys are the primary material used in the continuous extmsion of cable coverings for the electrical power cable industry in the United States. Other alloys, containing tin and arsenic as well as copper, have also been developed for cable sheathing in the United States to provide higher fatigue strength. 

Extmded or roUed lead—copper alloys contain a uniform dispersion of copper particles in a lead matrix. Because the soHd solubiUty of copper in lead is very low, copper particles in the matrix remain stable up to near the melting point of lead, maintaining uniform grain size even at elevated temperature. 

Fig. 14. Effects of iron (—), nickel (-), and copper (...) contaminant levels on the saltwater corrosion performance of magnesium AZ91 alloy containing...

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