Conductivity of metals and alloys

R.L. Powell, W.A. Blaupied Thermal Conductivity of Metal and Alloys at Low Temperatures, Nat. Bureau of Standards Circular 556, US Govt. Print. Office, Washington, DC (1954)... 

Table 2.5 Thermal conductivities of metals and alloys commonly used in electronic devices...

Table 2.5. Thermal Conductivities of Metals and Alloys Commonly Used in Electronic Devices and Assemblies...

Cu is used as the technical standard for the conductivity of metals and alloys. The International Annealed Copper Standard (lACS) is defined by a Cu wire, 1 m long and weighing 0.1kg, the resistance of which is 0.15327 at 20 °C. Accordingly, a conductivity of 100% lACS = 58.00MSm (ormS2 mm ), which corresponds to a resistivity of 1.7243793 ( xf2 cm). The electrical conductivity is specifically and strongly dependent on the kind and concentration of impurities (Fig. 3.1-130). 

Powell and Blanpied (1954) Thermal Conductivity of Metals and Alloys at Low Temperatures—A Review of the Literature by R. L. Powell and W. A. Blanpied, NBS Circular 56, National Bureau of Standards, Washington, DC. 

Because sodium, which is liquid between about 100°C and 881°C, has excellent properties as a heat-transfer medium, with a viscosity comparable with that of water and superior heat conductivity , much attention has been paid to liquid sodium corrosion testing of metal and alloys. Indeed, ASTM have issued a Standard Practice which can be used for determination... 

Electrical conduction in metals and alloys occms by the motion of electrons. It can be shown that the conductivity is proportional to the number of electrons per unit volume, Ug, the charge per electron, qg, and the electron mobility, pLg ... 

Over the past two decades, ionic liquids (ILs) have attracted considerable interest as media for a wide range of applications. For electrochemical applications they exhibit several advantages over the conventional molecular solvents and high temperature molten salts they show good electrical conductivity, wide electrochemical windows of up to 6 V, low vapor pressure, non-flammability in most cases, and thermal windows of 300-400 °C (see Chapter 4). Moreover, ionic liquids are, in most cases, aprotic so that the complications associated with hydrogen evolution that occur in aqueous baths are eliminated. Thus ILs are suitable for the electrodeposition of metals and alloys, especially those that are difficult to prepare in an aqueous bath. Several reviews on the electrodeposition of metals and alloys in ILs have already been published [1-4], A selection of published examples of the electrodeposition of alloys from ionic liquids is listed in Table 5.1 [5-40]. Ionic liquids can be classified into water/air sensitive and water/air stable ones (see Chapter 3). Historically, the water-sensitive chloroaluminate first generation ILs are the most intensively studied. However, in future the focus will rather be on air- and water-stable ionic liquids due to their variety and the less strict conditions under which... 

Media considerations. SCC tests can be divided into those conducted in natural environments, such as atmospheric exposure tests and seawater immersion tests, and those which are conducted under laboratory conditions or other fabricating operations. The principal disadvantage of atmospheric exposure tests is the comparatively long time required for their completion however, they are reliable since they can reflect the projected use. There is a standard practice for evaluating stress-corrosion cracking resistance of metals and alloys by alternate immersion in a solution of NaCl 3.5%, pH 6.5. For spray testing, ASTM B-117, 2003 states the relevant conditions for conducting the test. (ASTM G44)4... 

An interesting and potentially very useful property of the metallic state is superconductivity the conductivity of a number of metals and alloys increases dramatically at very low temperatures, as the electrons pass through the rigid... 

Localized corrosion of metals and alloys occurs in aggressive media (e.g., containing chloride) as a consequence of the passivity breakdown, with major impact in practical applications and on the economy. This form of corrosion is particularly insidious since a component, otherwise well protected by a well-adherent, ultrathin oxide or oxyhydroxide barrier layer (i.e., the passive film), can be perforated locally in a short time with no appreciable forewarning. Extensive studies have been conducted over the last five decades to understand localized corrosion by pitting [1-10], but the detailed mechanisms accounting for the local occurrence of passivity breakdown remain to be elucidated and combined with kinetics laws to allow reliable prediction. 

The corrosion of metals and alloys in potable water varies greatly depending on the water s composition. Among the factors that are most influential are oxygen content, pH, temporary hardness, chloride, sulfate, toted dissolved solids (TDS), and conductivity. Temporary hardness is sometimes referred to as carbonate hardness and is romoved easily by boiling. 

Because of the extensive use of copper-nickel in shipboard piping, the potential corrosivity of RO ultrapure water on these systems is considered important, ASTM G 4 (Standard Guide for Conducting Corrosion Coupon Tests in Field Application) covers in-plant testing of metals and alloys without regard to alloy t q)e, family, or class and generates test results by exposure of the materials to filtered seawater (RO feed stock), an intermediate-pass brine byproduct, and ultrapure product water. 

Alternative atmospheric cabinet simulation tests are available, including ASTM G 87, Practice for Conducting Moist SO2 Tests and ASTM G 85, Practice for Modified Salt Spray Testing. Service in environments where humidity or moisture varies may be simulated by cyclic humidity or alternate immersion tests. See ASTM G 60, Test Method for Conducting Cyclic Humidity Tests and ASTM G 44, Practice for Exposure of Metals and Alloys by Alternate Immersion in Neutral 3.5 % Sodium Chloride Solution. 

Lewin, R., Howson, R.P., Bishop, C A, Ridge, M.I. (1986). Transparent conducting oxides of metals and alloys made by reactive magnetron sputtering from elemental targets. Vacuum, Vol. 36, pp. 95-98. 

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