Copper-beryllium alloys electrical conductivity

Other popular alloys of beryllium are those with copper metal. Copper-beryllium alloys contain about 2 percent beryllium. They conduct heat and electricity almost as well as pure copper but are stronger, harder, and more resistant to fatigue (wearing out) and corrosion (rusting). These alloys are used in circuit boards, radar, computers, home appliances, aerospace applications, automatic systems in factories, automobiles, aircraft landing systems, oil and gas drilling equipment, and heavy machinery. 

Beryllium is obtained by electrolytic reduction of molten beryllium chloride. The element s low density makes it useful for the construction of missiles and satellites. Beryllium is also used as windows for x-ray tubes because Be atoms have so few electrons, thin sheets of the metal are transparent to x-rays and allow the rays to escape. Beryllium is added in small amounts to copper the small Be atoms pin the Cu atoms together in an interstitial alloy that is more rigid than pure copper but still conducts electricity well. These hard, electrically conducting alloys are formed into nonsparking tools for use in oil refineries and grain elevators, where there is a risk of explosion. Beryllium-copper alloys are also used in the electronics industry to form tiny nonmagnetic parts and contacts that resist deformation and corrosion. 

Copper and Alloys Copper and its alloys are widely used in chemical processing, particularly when heat and electrical conductivity are important factors. The thermal conductivity of copper is twice that of aluminum and 90 percent that of silver. A large number of copper alloys are available, including brasses (Cu-Zn), bronzes (Cu-Sn), cupronickels (Cu-Ni), and age-hardenable alloys such as copper beryllium (Cu-Be) and copper nickel tin (Cu-Ni-Sn). 

Alloys of beryllium and of other metals with beryllium are also important. Beryllium-aluminum alloy (62%Be, 38%A1) and beryllium-copper master alloy are both available commercially The incorporation of 2% Be into copper greatly increases the hardness and strength of the metal without reducing its electrical and thermal conductance. This is the single largest use of beryllium. 

Beryllium is used commercially in three major forms as a pure metal, as an alloy with other metals, and as a ceramic. The favorable mechanical properties of beryllium, e.g., its specific stiffness, have made it a major component for certain aerospace applications in satellites and spacecraft. As a modulator and reflector of neutrons, beryllium is of interest in fusion reactions and for nuclear devices that have defense applications. When a small amount of beryllium is added to copper, the desirable properties of copper (i.e., thermal and electrical conductivity) are kept but the material is considerably stronger. The superior thermal conductivity of beryllium oxide ceramics has made the product useful for circuit boards and laser tubes. A more complete discussion of the applications of beryllium was recently reviewed [2]. 

The converter consists of 1,536 pairs of thermopiles made of silicon-germanium alloy (Si 85% by mass, Ge 15% by mass) with n- and p-conductivity. Each module of 16 thermopiles is mounted on the inner surface of the hermetically sealed steel vessel. To provide for a good contact on the reactor heating, each module is pressed on the reflector by gas bellows elements. On the hot side, the keyboard consists of molybdenum plates, on the cold one - of copper bridges. To prevent an electric contact (shorting), insulating plates of beryllium oxide are used on the hot and cold sides. The excess heat is removed from the reactor-converter by shaped enamel-coated copper fins with an emissivity of at least 0.9 (O Fig. 59.2). 

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