Bismuth fusible alloy

Until 1930, approximately 90% of bismuth usage was for pharmaceutical appHcations (9). From that point until the 1970s, research produced new appHcations that greatiy expanded the uses of the metal. At that point the pharmaceutical use accounted for about 50% of the total bismuth consumption. By 1991, the fusible alloy category along with the other subdivisions each accounted for about 10% of the bismuth usage. Pharmaceutical usage was down to 20%. 

The United States consumed 1500 metric tons of bismuth in 1988 and exported 147 t (1). The average domestic dealer price was 12.74/kg. The world mine output, excluding the United States, was estimated to be 2770 t in 1988 the world refinery production was estimated as 3510 t. Of the bismuth consumed in the United States, 679 t was used for industrial and laboratory chemicals, cosmetics (qv), and pharmaceuticals (qv) 333 t for fusible alloys 493 t for metaHurgical additives 12 t for other alloys and 15 t for miscellaneous purposes. 

W orld annual production of bismuth and its compounds has hovered around 4000 tonnes of contained Bi for many years and a similar amount of secondary (refinery) Bi is also produced. Production has been dominated by China, Japan, Peru, Bolivia, Mexico, Canada, USA and Australia which, between them, account for almost of all supplies. Prices tor die free element have fluctuated wildly since the 1970s, from < 4 (Xl/kg to > 44.00/kg at die end of 1990 it was 6.30/kg Consumption of the metal and its compounds has also been unusual, usage in the USA dropping by a factor of 2 from 1973 to 1975, for example. The mam uses are in pharmaceuticals, fusible alloys (including type metal, p. 547), and metallurgical additives. 

Alloys are mixtures of metals combined to obtain specific characteristics and enhanced properties for a particular application. The term fusible metals or fusible alloys denotes a group of alloys that have melting points below that of tin (232°C, 449°F). Most of these substances are mixtures of metals that by themselves have relatively low melting points, such as tin, bismuth (m.p. 275°C), indium (157°C),... 

Further additions of bismuth, cadmium, and antimony to the tin-lead alloys result in the low inching or "fusible" alloys widely used as safety... 

Fusible Alloys. —Among the eutectic alloys, some are known as fusible alloys. Wood s alloy consists of two parts of tin, two of lead, seven or eight of bismuth, and one or two of cadmium it melts at 66°- ] i ° an alloy melting at 6o° (Lipowitz s) consists of tin four parts, lead eight parts, bismuth fifteen parts, and cadmium three parts. 

What is unusual about Onion s Fusible Alloy compared to other metals Onion s Fusible Alloy contains bismuth, lead, and tin. Compare the melting points of these metals to the melting point of Onion s Fusible Alloy. 

Wood s metal. A four-component fusible alloy used largely in sprinkler systems, it melts at 70C, the composition being bismuth 50%, cadmium 10%, tin 13.3%, lead 26.7%. 

An alloy known as Wood s Fusible Alloy, which melts at a much lower temperature even, is composed of tin, two parts lead, two parts bismuth, seven parts cadimiun, one to two parts. This melts at about 68 centigrade, boiling point loo . 

Occurs sometimes as metal, more frequently as sulphuret. It is a highly crystalline metal, of a reddish white colour, fusible at 476 , and even volatile in close vessels. When heated in the air it bums with a bluish flame, forming oxide of bismuth. Bismuth is an ingredient in Newton s fusible metal, and in various fusible alloys. 

Rose s metal A fusible alloy containing 50% bismuth, 25-28% lead, and tin. Its low melting point (about 100°C) leads to its use in fire-protection devices. 

Take bismuth, 8 pp. uS lead, 5 parts tin, 2 parts, and form tliem into an alloy in tlie following manner. First melt the lead in a crucible (it melts at 334 ) then add the tin and bismuth (v tiny pieces), and stir well. This fusible alloy, not jnlik lead in appearance, melts in boiling or even vei hot kvater. By first melting the alloy ami then addin nierciu 7, a solid is produced which melts in wV r considerably U>eiow boiling-point. 

Low Melting Alloys. Lead ahoys having large amounts of bismuth, tin, cadmium, and iadium that melt at relatively low (10—183°C) temperatures are known as fusible or low melting ahoys. The specifications of many of these ahoys are Hsted ia ASTM B774-87 (7). 

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