Copper resistivity

Copper alloys are attacked at high pH. However, attack is usually caused not by elevated pH alone but because of copper complexation by ammonia or substituted ammonium compounds. In fact, copper resists corrosion in caustic solutions. For example, corrosion rates in hot caustic soda may be less than 1 mil/y (0.025 mm/y). 

Antimony (Sb), 3 41-56, 56. See also Group Ill-Sb system InAsSb alloy InSb photodiode detectors/arrays Lead-antimony alloys Low antimony lead alloys Stib- entries in babbitts, 24 797 catalyst poison, 5 257t chemical reactions, 3 42—44 in coal, 6 718 economic aspects, 3 47-48 effect of micro additions on silicon particles in Al-Si alloys, 2 311-312 effect on copper resistivity, 7 676t environmental concerns, 3 50 gallium compounds with, 12 360 health and safety factors, 3 51 in pewter, 24 798... 

Beryllium (Be), 3 637-661. See also Beryllium compounds analysis, 3 645-647 chemical reactions, 3 639-640 in coal, 6 718-719 commercial grades, 3 644t economic aspects, 3 644-645 effect on copper resistivity, 7 676t fabrication, 3 642-644 in galvanic series, 7 805t handling, 3 647... 

Cobalamin, 25 803 folic acid and, 25 802 Cobalt (Co), 7 207-228. See also Co-base superalloys 60Co isotope 60Co nucleus Fe-Ni-Co alloys Dicobalt octacarbonyl Tetracobalt dodecacarbonyl analysis, 7 215-216 in ceramic-matrix composites, 5 554t coke formation on, 5 266 colloidal suspensions, 7 275 economic aspects, 7 214-215 effect on copper resistivity, 7 676t environmental concerns, 7 216 health and safety factors, 7 216-218 in M-type ferrites, 11 66, 69 occurrence, 7 208... 

The compound consisting of yttrium, copper, and barium oxide, commonly called compound 1-2-3, was formed in 1987 by research scientists at the universities of Alabama and Houston. It had limited superconducting capabilities. It has been known for some time that conductors of electricity such as copper resist, to some extent, the flow of electrons at normal temperatures, but at temperatures near absolute zero (zero Kelvin = -273°C), this resistance to the flow of electrons in some materials is reduced or eliminated. The 1-2-3 compound proved to be superconducting at just 93°K, which is still much too cold to be used for everyday transmission of electricity at normal temperatures. Research continues to explore compounds that may achieve the goal of high-temperature superconductivity. 

Copper is softer and more ductile than steel and is utilized frequently in the manufacture of pipes and tubing. Copper has good corrosion resistance but will corrode in the presence of nitric acid and other mineral acids. Organic acids do not corrode copper as readily. Dry ammonia does not corrode copper, but the presence of water in ammonia and ammonium hydroxide will corrode copper. Copper resists corrosion in the presence of caustic solutions, but the addition of zinc will increase corrosion rates. Also carbonate, phosphate, and silicate salts of sodium will corrode copper. See FIGURE 9-1. 

Mills, S.D. Jasalavich, C.A. Cooksey, D.A. A two-component regulatory system required for copper-inducible expression of the copper resistance operon of Pseudomonas syringae. J. Bacteriol., 175, 1656-1664 (1993)... 

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