Zinc alloys physical properties

Solders. In spite of the wide use and development of solders for millennia, as of the mid-1990s most principal solders are lead- or tin-based alloys to which a small amount of silver, zinc, antimony, bismuth, and indium or a combination thereof are added. The principal criterion for choosing a certain solder is its melting characteristics, ie, soHdus and Hquidus temperatures and the temperature spread or pasty range between them. Other criteria are mechanical properties such as strength and creep resistance, physical properties such as electrical and thermal conductivity, and corrosion resistance. 

The physical properties of zinc and the diecasting alloys are given in Table 4.31. 

Table 4.31 Physical properties of zinc and cast zinc alloys...

The /3-alloys are different in nature from the 7-alloys and the a-manganese and /3-manganese structures discussed above, in that they are not complex structures, but are simple, being based upon the body-centered arrangement. /3-Brass, for example, has either a disordered structure, above 480°K, the copper and zinc atoms in essentially equal number being distributed largely at random over the points of a body-centered cubic lattice, or an ordered structure, below 300°K, with copper and zinc at the positions 000 and, respectively, of the cubic unit. Moreover, the physical properties of /3-brass are not those that indicate a filled zone structure. 

Lanthanum is the fourth most abundant of the rare-earths found on the Earth. Its abundance is 18 ppm of the Earth s crust, making it the 29th most abundant element on Earth. Its abundance is about equal to the abundance of zinc, lead, and nickel, so it is not really rare. Because the chemical and physical properties of the elements of the lanthanide series are so similar, they are quite difficult to separate. Therefore, some of them are often used together as an alloy or in compounds. 

Refs. [i] Habashi F (ed) (1998) Alloys, preparation, properties, applications. Wiley-VCH, Weinheim [ii] Matucha KH (1996) Structure and properties of nonferrous alloys. In Matucha KH (ed) Materials science and technology. A comprehensive treatment, vol 8. VCH, Weinheim [iii] Fleischer A, Lander J, (eds) (1971) Zinc-silver oxide batteries. Wiley, Chichester [iv] Hicks HG (1960) The radiochemistry of zinc. McGraw-Hill, New York [v] Linden D, Thomas BR (eds) (2002) Handbook of batteries, 3rd edn McGraw-Hill, New York [vi] Pauling L (1970) General chemistry, 3rd edn. Freeman, San Francisco [vii] Lide DR (ed) (2003-2004) Handbook of chemistry and physics, 84th edn. CRC Press, Boca Raton [viii] http //periodic.lanl.gov/elements/30.html... 

Zinc in alloyed form can be cast with fine detail into complicated shapes and can be formed with extra thin walls (0.5 mm). Specifiers can choose from a family of zinc alloys and a range of casting processes that are the most suited for their products. Zinc alloy castings are unique, particularly when produced by the pressure die-casting process. They can be made to extremely close tolerance, with excellent surface finish, have a range of useful physical and mechanical properties and can receive a wide range of applied finishes. Typical applications are precision parts for vehicles, aircraft and communications equipment, plumbing hardware, construction fixtures, household appliance, zippers and toys. 

Apart from natural emissions, Cd is usually found in the environment because of several anthropogenic activities. Due to its chemical and physical properties, Cd is widely used in special alloys (e.g., copper-, tin-, lead-, or zinc-based alloys), pigments (as Cd sulfide and sufoselenide), stabilizers (e.g., Cd incorporated into poly(vinyl chloride)), NiCd batteries and coatings (e.g., steel, aluminum and other non-ferrous metals). Of course, the manufacturing. 

The physical properties of many metals render them unsuitable for fabrication and engineering purposes. By combining two or more metals, or metals with non-metals, one can form alloys with enhanced properties such as strength, malleability, ductility, hardness or resistance to corrosion. For example, copper is alloyed with zinc (2-40% by weight) to produce different types of brasses which are stronger than copper but retain good fabrication properties. 

Zinc (Zn) is a bluish-white, lustrous metal and was discovered in 1746. It is extensively used to form numerous alloys with other metals. Cadmium (Cd) was discovered in 1817 from an impurity in zinc carbonate. Cd is a soft, bluish-white metal and can be easily cut with a knife. Mercury (Hg) is known to ancient Chinese and Hindus. It was found in Egyptian tombs of 1500 B.C. It is the only common metal liquid at ordinary temperatures. Hg is known to be used in making mercury-vapor lamps. Table 2.21 summarizes some physical properties of group-IIb metals. 

Even though copper has many useful properties, it is not a very strong metal therefore, alloys of copper with improved strength have been developed. Bronze was one of the first alloys ever produced. This alloy of copper and tin has been used for thousands of years because it could be made even in the low heat of a Stone Age campfire. Brass, another widely used alloy, contains copper and zinc. Many brass and bronze alloys also contain other metals to achieve certain physical properties. Some of the most important applications of bronze and brass are for plumbing fixtures, bearings, and art decorations. In addition, the tendency of brass and bronze alloys (unlike those of iron) not to spark when struck make them useful in applications where sparks could be dangerous. 

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