Handbook Corrosion (1992) WW Part 7 pdf

35. R.H. Brown, Aluminum Alloy Laminates: Alclad and Clad Aluminum Alloy Products, in Composite Engineering Laminates, A.G.H. Dietz, Ed., M.I.T. Press, 1969 36. M.R. Bothwell, New Technique Enhances Corrosion Resistance of Aluminum, Met. Prog., Vol 87, March 1985, p 81 37. H. Ikeda, Protection Against Pitting Corrosion of 3003 Aluminum Alloy by Zinc Diffusion Treatment, Aluminum, Vol 58 (No. 8), 1982, p 467 38. D.J. Scott, Aluminum Sprayed Coatings Their Use for the Protection of Al Alloys and Steel, Trans, IMF, Vol 49, 1971, p 111 39. V.E. Carter and H.S. Campbell, Protecting Strong Aluminum Alloys Against Stress- Corrosion With Sprayed Metal Coatings, Br. Corros. J., Vol 4, 1969, p 15 40. W.J. Schwerdtfeger, Effects of Cathodic Protection on the Corrosion of an Aluminum Alloy, J. Res. Natl. Bur. Stand., Vol 68C (No. 4), 1964, p 283 41. Recommended Practice for Cathodic Protection of Aluminum Pipe Buried in Soil or Immersed in Water, Mater. Protec., Vol 2 (No. 10), 1963, p 106 42. F.W. Hewes, Investigation of Maximum and Minimum Criteria for the Cathodic Protection of Aluminum in Soil, Oil Week, Vol 16 (No. 24-28), Aug-Sept 1965 43. M. Cerny, Present State of Knowledge About Cathodic Protection of Aluminum, Prot. Met., Vol 11 (No. 6), 1975, p 645 44. R.B. Mears and H.J. Fahrney, Cathodic Protection of Aluminum Equipment, Trans. AIChE, Vol 37 (No. 6), 1941, p 911 45. B. Sandberg and A. Bairamov, "Cathodic Protection of Aluminum Structures," Report 198 5:2, Swedish Corrosion Institute, 1985 46. T.J. Lennox, M.H. Peterson, and R.E. Groover, "Corrosion of Aluminum Alloys by Antifouling Paint Toxicants and Effects of Cathodic Protection," Paper 16, presented at NACE Conference, Cleveland, OH, National Association of Corrosion Engineers, 1968 47. R.E. Groover, T.J. Lennox, and M.H. Peterson, Cathodic Protection of 19 Aluminum Alloys Exposed to Seawater Corrosion Behavior, Mater. Protec., Vol 8 (No. 11), 1969, p 25 48. S.C. Dexter, Localized Corrosion of Aluminum Alloys for OTEC Heat Exchangers, J. Ocean Sci. Eng., Vol 8 (No. 1), 1981, p 109 49. E.H. Cook and F.L. McGeary, Electrodeposition of Iron From Aqueous Solutions Onto an Aluminum Alloy, Corrosion, Vol 20 (No. 4), 1964, p 111t 50. J.D. Edwards, F.C. Frary, and Z. Jeffries, The Aluminum Industry: Aluminum Products and Their Fabrication, McGraw-Hill, 1930 51. M.H. Brown, W.W. Binger, and R.H. Brown, Mercury and its Compounds: A Corrosion Hazard, Corrosion, Vol 8 (No. 5), 1952, p 155 52. R.C. Plumb, M.H. Brown, and J.E. Lewis, A Radiochemical Tracer Investigation of the Role of Mercury in the Corrosion of Aluminum, Corrosion, Vol 11 (No. 6), 1956, p 277t 53. E.H. Dix, Acceleration of the Rate of Corrosion by High Constant Stresses, Trans. AIME, Vol 1 37, 1940, p 11 54. W.L. Fink and L.A. Willey, Quenching of 75S Aluminum Alloy, Met. Technol., Vol 14 (No. 8), 1947, p 5 55. M.S. Hunter, G.R. Frank, and D.L., Robinson, in Proceedings of Conference: Fundamental Aspects of Stress-Corrosion Cracking, R.W. Staehle, Ed., National Association of Corrosion Engineers, 1969, p 497 56. H. Kaesche, Pitting Corrosion of Aluminum and Intergranular Corrosion of Aluminum Alloys, in Localized Corrosion, B.F. Brown, J. Kruger, and R.W. Staehle, Ed., National Association of Corrosion Engineers, 1974, p 516 57. J.R. Galvele and S.M. de Micheli, Mechanism of Intergranular Corrosion of Al-Cu Alloys, Corros. Sci., Vol 10, 1970, p 795 58. "Standard Practice for Determining the Susceptibility to Intergranular Corrosion of 5xxx Series Aluminum Alloys by Weight Loss After Exposure to Nitric Acid (NAWLT Test)," G 67, Annual Book of ASTM Standards, American Society for Testing and Materials 59. R.B. Mears, R.H. Brown, and E.H. Dix, Jr., A Generalized Theory of the Stress-Corrosio n Cracking of Alloys, in Symposium on Stress-Corrosion Cracking of Metals, American Society for Testing and Materials and American Institute of Mining and Metallurgical Engineers, 1945, p 323 60. D.O. Sprowls and R.H. Brown, Stress-Corrosion Mechanisms for Aluminum Alloys, in Fundamental Aspects of Stress-Corrosion Cracking, R.W. Staehle, A.J. Forty, and D. VanRooyen, Ed., National Association of Corrosion Engineers, 1969, p 466 61. M.O. Speidel, Hydrogen Embrittlement of Aluminum Alloys, in Hydrogen in Metals, L.M. Bernstein and A.W. Thompson, Ed., American Society for Metals, 1974, p 249 62. V.A. Marichev, The Mechanism of Crack Growth in Stress Corrosion Cracking of Aluminum Alloys, Werkst. Korros., Vol 34, 1983, p 300 63. E.H. Spuhler and C.L. Burton, "Avoiding Stress- Corrosion Cracking in High Strength Aluminum Alloy Structures," Green Letter, Alcoa, 1970 64. Aluminum Standards and Data, The Aluminum Association, 1984, p 12 65. J.G. Rinker, M. Marek, and T.H. Sanders, Jr., Microstructure, Toughness and SCC Behavior of 2020, in Aluminum-Lithium Alloys, T.H. Sanders, Jr. and E.A. Starke, Jr., Ed, American Institute of Mining, Metallurgical, and Petroleum Engineers, 1983, p 597 66. A.K. Vasudevan, P.R. Ziman, S.C. Jha, and T.H. Sanders, Jr., Stress-Corrosion Resistance of Al-Cu-Li- Zr Alloys, in Aluminum-Lithium Alloys, Vol III, C. Baker, P.J. Gregson, S.J. Harris, and C.J. Peel, Ed., The Institute of Metals, 1986, p 303 67. E.L. Colvin, S.J. Murtha, and R.K. Wyss, The Effect of Aging Time on the Stress- Corrosion Cracking Resistance of 2090- T8E41, to be published in the proceedings of the International Conference on Aluminum Alloys, Charlottesville, VA, 15-20 June 1986 68. N.J.H. Holroyd, A. Gray, G.M. Scamans, and R. Herman, Environment-Sensitive Fracture of Al-Li-Cu- Mg Alloys, in Aluminum-Lithium Alloys, Vol III, C. Baker, P.J. Gregson, S.J. Harris, and C.J. Peel, Ed., The Institute of Metals, 1986, p 310 69. "Standard Recommended Practice of Alternate Immersion Stress Corrosion Testing in 3.5% Sodiu m Chloride Solution," G 44, Annual Book of ASTM Standards, American Society for Testing and Materials 70. "Standard Recommended Practice for Determining Susceptibility to Stress-Corrosion Cracking of High- Strength Aluminum Alloy Products," G 47, Annual Book of ASTM Standards, American Society for Testing and Materials 71. "Standard Test Method for Visual Assessment of Exfoliation Corrosion Susceptibility of 5 xxx Series Aluminum Alloys (ASSET Test)," G 66, Annual Book of ASTM Standards, American Society f or Testing and Materials 72. "Standard Test Method for Exfoliation Corrosion Susceptibility in 2 xxx and 7 xxx Series Aluminum Alloys (EXCO Test)," G 34, Annual Book of ASTM Standards, American Society for Testing and Materials 73. "Standard Method of Acidified Synthetic Sea Water (Fog) Testing," G 43, Annual Book of ASTM Standards, American Society for Testing and Materials 74. "Standard Practice for Modified Salt Spray (Fog) Testing," G 85, Annual Book of ASTM Standards, American Society for Testing and Materials 75. "Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate," B 209, Annual Book of ASTM Standards, American Society for Testing and Materials 76. "Exfoliation Corrosion Testing of Aluminum Alloys 5086 and 5456," Technical Rep ort T1, Aluminum Association, circa 1972 77. D.O. Sprowls, J.D. Walsh, and M.B. Shumaker, Simplified Exfoliation Testing of Aluminum Alloys, in Localized Corrosion Cause of Metal Failure, STP 516, American Society for Testing and Materials, 1972, p 38 78. T.J. Summerson, "Aluminum Association Task Group on Exfoliation and Stress- Corrosion Cracking of Aluminum Alloys for Boat Stock," Interim Report, in Proceedings of the Tri- Service Conference on Corrosion of Military Equipment, Technical Report AFML-TR-75-42, Vol II, 1972, p 193 79. S.J. Ketcham and P.W. Jeffrey, Exfoliation Corrosion Testing of 7178 and 7075 Aluminum Alloys, in Localized Corrosion Cause of Metal Failure, STP 516, American Society for Testing and Materials, 1972, p 273 80. B.W. Lifka a nd D.O. Sprowls, Relationship of Accelerated Test Methods for Exfoliation Resistance in 7xxx Series Alloys with Exposure to a Seacoast Atmosphere, in Corrosion in Natural Environments, STP 558, American Society for Testing and Materials, 1974, p 306 81. O.F. Devereux, A.J. McEvily, and R.W. Staehle Ed., Corrosion Fatigue: Chemistry, Mechanics, and Microstructure, Part VII, Aluminum Alloys, National Association of Corrosion Engineers, 1972, p 451 82. H.L. Craig, T.W. Hooker, and D.W. Hoeppner, Ed., Corrosion Fatigue Technology, STP 642, American Society for Testing and Materials, 1978, p 51 83. J.E. Hatch, Ed., Aluminum: Properties and Physical Metallurgy, American Society for Metals, 1984 84. S.J. Ketcham and E.J. Jankowsky, Developing an Accelerated Test: Problems and Pitfalls, in Laboratory Corrosion Tests and Standards, G.S. Haynes and R. Babioan, Ed., STP 866, American Society for Testing and Materials, 1985, p 14 85. G. Sowinski and D.O. Sprowls, Weathering of Aluminum Alloys, in Atmospheric Corrosion, W.H. Ailor, Ed., John Wiley & Sons, 1982, p 297 86. M.A. Pelensky, J.J. Jaworski, and A. Galliccio, Corrosion Investigations at Panama Canal Zone, in Atmospheric Factors Affecting the Corrosion of Engineering Materials, S.K. Coburn, Ed., STP 646, American Society for Testing and Materials, 1976, p 58 87. C.J. Walton, D.O. Sprowls, and J.A. Nock, Jr., Resistance of Aluminum Alloys to Weathering, Corrosion, Vol 9 (No. 10), 1953, p 345 88. W.W. Binger, R.H. Wagner, and R.H. Brown, Resistance of Aluminum Alloys to Chemically Contaminated Atmospheres, Corrosion, Vol 9 (No. 12), 1953, p 440 89. F.L. McGeary, E.T. Englehart, and P.J. Ging, Weathering of Aluminum, Mater. Protec., Vol 6 (No. 6), 1967, p 33 90. C.J. Walton and W. King, Resistance of Aluminum-Base Alloys to 20- Year Atmospheric Exposure, in STP 174, American Society for Testing and Materials, 1956, p 21 91. S.M. Brandt and L.H. Adams, Atmospheric Exposure of Light Metals, in STP 435, American Society for Testing and Materials, 1968, p 95 92. W.K. Boyd and F.W. Fink, "Corrosion of Metals in the Atmosphere," Report MCIC-74- 33, Battelle Memorial Institute, 1974 93. S.C. Byrne and A.C. Miller, Effect of Atmospheric Pollutant Gases on the Formation of Corrosive Condensate on Aluminum, in Atmospheric Corrosion of Metals, S.W. Dean, Jr. and E.C. Rhea, Ed., STP 767, American Society for Testing and Materials, 1982, p 395 94. F. Mattsen and S. Lindgren, Hard-Rolled Aluminum Alloys, in Metal Corrosion in the Atmosphere, STP 435, American Society for Testing and Materials, 1968, p 240 95. T.P Hoar, Discussion on Filiform Corrosion, Chem. Ind., Nov 1952, p 1126 96. W.H. Slaybaugh, W. DeJager, S.E. Hoover, and L.L. Hutchinson, Filiform Corrosion of Aluminum, J. Paint Technol., Vol 44 (No. 556), 1972, p 76 97. W.W. Binger and C.M. Marstiller, Aluminum Alloys for Handling High Purity Water, Corrosion, Vol 13 (No. 9), 1957 98. J.E. Draley and W.E. Ruther, Aqueous Corrosion of Aluminum, Part 2 Methods of Protection Above 200 °C, Corrosion, Vol 12 (No. 10), 1965, p 480t 99. D.W. Sawyer and R.H Brown, Resistance of Aluminum Alloys to Fresh Waters, Corrosion, Vol 3 (No. 9), 1947, p 443 100. H.P. Godard, The Corrosion Behavior of Aluminum in Natural Waters, Can. J. Chem. Eng., Vol 38, 1960, p 167 101. W.H. Ailor, Jr., A Review of Aluminum Corrosion in Tap Water, J. Hydronautics, Vol 3 (No. 3), 1969, p 105 102. B.R. Pathak and H.P. Godard, Equations for Predicting the Corrosivities of Natural Fresh Waters to Aluminum, Nature, Vol 218 (No. 5144), June 1968, p 893 103. W.A. Prey, N.W. Smith, and C.L. Wood, Jr., Marine Applications, in Aluminum, Vol II, K.R. Van Horn, Ed., American Society for Metals, 1967, p 389 104. K.G. Compton, Seawater Tests, in Handbook on Corrosion Testing and Evaluation, W.H. Ailor, Ed., John Wiley & Sons, 1971, p 507 105. W.K. Boyd and F.W. Fink, "Corrosion of Metals in Marine Environments," Report MCIC-74- 245R, Battelle Memorial Institute, 1975 106. W.H. Ailor, Jr., Ten-Year Seawater Tests on Aluminum, in Corrosion in Natural Environments, STP 558. American Society for Testing and Materials, 1974, p 117 107. F.M. Reinhart, "Corrosion of Metals and Alloys in the Deep Ocean," Report R834, U.S. Naval Engineering Laboratory, 1976 108. S.C. Dexter, Effect of Variations in Seawater Upon the Corrosion of Aluminum, Corrosion, Vol 36 (No. 8), 1980, p 423 109. H.T. Rowland and S.C. Dexter, Effects of the Seawater Carbon Dioxide System on the Corrosion of Aluminum, Corrosion, Vol 36 (No. 9), 1980, p 458 110. S.C. Dexter, K.E. Lucas, J. Mihm, a nd W.E. Rigby, "Effect of Water Chemistry and Velocity of Flow on Corrosion of Aluminum," Paper 64, presented at Corrosion/83, Anaheim, CA, National Association of Corrosion Engineers, 1983 111. J. Larsen-Basse and S.H. Zaida, Corrosion of Some Aluminum A lloys in Tropical Surface and Deep Ocean Seawater, in Proceedings of the International Congress on Metallic Corrosion, Vol 4, June 1984, p 511 112. R.S.C. Munier and H.L. Craig, "Ocean Thermal Energy Conversion (OTEC) Biofouling and Corrosion Experiment ( 1977), St. Croix, U.S. Virgin Is., Part II, Corrosion Studies," Pacific Northwest Laboratory, Report PNL-2739, Feb 1978 113. D.S. Sasscer, T.O. Morgan, R. Ernst, T.J. Summerson, and R.C. Scott, "Open Ocean Corrosion Test of Candidate Aluminum Materials fo r Seawater Heat Exchangers," Paper 67, presented at Corrosion/83, Anaheim, CA, National Association of Corrosion Engineers, 1983 114. M. Romanoff, "Underground Corrosion," NBS 579, National Bureau of Standards, 1957 115. D.O. Sprowls and M.E. Carlisle, Resistance of Aluminum Alloys to Underground Corrosion, Corrosion, Vol 17, 1961, p 125t 116. T.E. Wright, New Trends in Buried Aluminum Pipelines, Mater. Perform., Vol 15 (No. 9), 1976, p 26 117. Recommended Practice for Cathodic Protection of Aluminum Pi pe Buried in Soil or Immersed in Water, Mater, Protec., Vol 2 (No. 10), 1963, p 106 118. J.A. Apostolos and F.A. Myhres, "Cooperative Field Survey of Aluminum Culverts," Report FHWA/CA/TL80-12, California Department of Transportation, 1980 119. T.E. Wright, The Corrosion Behavior of Aluminum Pipe, Mater, Perform., Vol 22 (No. 12), 1983, p 9 120. W.C. Cochran, Anodizing, in Aluminum: Fabrication and Finishing, Vol III, K.R. Van Horn, Ed., American Society for Metals, 1967, p 641 121. W.C. Cochran and D.O . Sprowls, "Anodic Coatings for Aluminum," Paper presented at Conference on Corrosion Control by Coatings, Lehigh University, Nov 1978 122. D.O. Sprowls et al., "Investigation of the Stress- Corrosion Cracking of High Strength Aluminum Alloys," Final Report, Contract No. NAS-8- 5340 for the period of May 1963 to Oct 1966, Accession No. NASA CR88110, National Technical Information Center, 1967 123. C.J. Walton, F.L. McGeary, and E.T. Englehart, The Compatibility of Aluminum with Alkaline Building Products, Corrosion, Vol 13, 1957, p 807t 124. Aluminum in the Chemical and Food Industries, The British Aluminum Company, Norfolk House, 1959 125. Aluminum Statistical Review for 1984, The Aluminum Association, 1984 126. E.H. Cook, R.L. Horst, and W.W. Binger, Co rrosion Studies of Aluminum in Chemical Process Operations, Corrosion, Vol 17 (No. 1), 1961, p 97 127. R.L. Horst, Structures and Equipment for the Chemical, Food, Drug, Beverage and Atomic Industries, in Aluminum: Design and Application, Vol II, K.R. Van Horn, Ed., American Society for Metals, 1967, p 259 128. Guidelines for the Use of Aluminum With Food and Chemicals, 5th ed., The Aluminum Association, April 1984 129. Care of Aluminum, The Aluminum Association, 1977 130. E.T. Englehart, Cleaning and Maintenance of Surfaces, in Aluminum, Vol III, K.R. Van Horn, Ed., American Society for Metals, 1967, p 757 Selected References • J.D. Edwards, F.C. Frary, and Z. Jeffries, The Aluminum Industry: Aluminum Products and Their Fabrication, McGraw-Hill, 1930 • U.R. Evans, The Corrosion and Oxidation of Metals: Scientific Principles and Practical Applications, E. Arnold, 1960 • H.P. Godard, W.B. Jepson, M.R. Bothwell, and R.L. Kane, The Corrosion of Light Metals, John Wiley & Sons, 1967 • Guidelines for the Use of Aluminum with Foods and Chemicals, 5th ed., Aluminum Association, Inc., April 1984 • J.E. Hatch, Ed., Aluminum: Properties and Physical Metallurgy, American Society for Metals, 1984 • F.L. LaQue and H.R. Copson, Corrosion Resistance of Metals and Alloys, 2nd ed., Reinhold, 1963 • L.F. Mondolfo, Aluminum Alloys: Structure and Properties, Butterworths, 1976 • L.L. Shrier, Corrosion, Vol I and II, 2nd ed., Newnes-Butterworths, 1976 • H.H. Uhlig, Ed., Corrosion Handbook, John Wiley & Sons, 1948 • K.R. Van Horn, Ed., Aluminum, Vol I, II, and III, American Society for Metals, 1967 Corrosion of Copper and Copper Alloys By the ASM Committee on Corrosion of Copper * ; Chairman: Ned W. Polan, Olin Corporation Introduction COPPER AND COPPER ALLOYS are widely used in many environments and applications because of their excellent corrosion resistance, which is coupled with combinations of other desirable properties, such as superior electrical and thermal conductivity, ease of fabricating and joining, wide range of attainable mechanical properties, and resistance to biofouling. Copper corrodes at negligible rates in unpolluted air, water, and deaerated nonoxidizing acids. Copper alloy artifacts have been found in nearly pristine condition after having been buried in the earth for thousands of years, and copper roofing in rural atmospheres has been found to corrode at rates of less than 0.4 mm (15 mils) in 200 years. Copper alloys resist many saline solutions, alkaline solutions, and organic chemicals. However, copper is susceptible to more rapid attack in oxidizing acids, oxidizing heavy-metal salts, sulfur, ammonia (NH 3 ), and some sulfur and NH 3 compounds. Resistance to acid solution depends mainly on the severity of oxidizing conditions in the solution. Reaction of copper with sulfur and sulfides to form copper sulfide (CuS or Cu 2 S) usually precludes the use of copper and copper alloys in environments known to contain certain sulfur species. Copper and copper alloys provide superior service in many of the applications included in the following general classifications: • Applications requiring resistance to atmospheric exposure, such as roofing and other architectural uses, hardware, building fronts, grille work, hand rails, lock bodies, doorknobs, and kick plates • Freshwater supply lines and plumbing fittings, for which superior resistance to corrosion by various types of waters and soils is important • Marine applications most often freshwater and seawater supply lines, heat exchangers, condensers, shafting, valve stems, and marine hardware in which resistance to seawater, hydrated salt deposits, and biofouling from marine organisms is important • Heat exchangers and condensers in marine service, steam power plants , and chemical process applications, as well as liquid-to-gas or gas-to- gas heat exchangers in which either process stream may contain a corrosive contaminant • Industrial and chemical plant process equipment involving exposure to a wide variety of organic and inorganic chemicals • Electrical wiring, hardware, and connectors; printed circuit boards; and electronic applications that require demanding combinations of electrical, thermal, and mechanical properties, such as semiconductor packages, lead frames, and connectors Copper and its alloys are unique among the corrosion-resistant alloys in that they do not form a truly passive corrosion product film. In aqueous environments at ambient temperatures, the corrosion product predominantly responsible for protection is cuprous oxide (Cu 2 O). This Cu 2 O film is adherent and follows parabolic growth kinetics. Cuprous oxide is a p-type semiconductor formed by the electrochemical processes: 4Cu + 2H 2 O 2Cu 2 O + 4H + + 4e - (anode) (Eq 1) and O 2 + 2H 2 O + 4e - 4(OH) - (cathode) (Eq 2) with the net reaction: 4Cu + O 2 2Cu 2 O. For the corrosion reaction to proceed, copper ions and electrons must migrate through the Cu 2 O film. Consequently, reducing the ionic or electronic conductivity of the film by doping with divalent or trivalent cations should improve corrosion resistance. In practice, alloying additions of aluminum, zinc, tin, iron, and nickel are used to dope the corrosion product films, and they generally reduce corrosion rates significantly. Note * Frank J. Ansuini, Consulting Engineer; Carl W. Dralle, Ampco Metal; Fraser King, Whiteshell Nuclear Research Establishment; W.W. Kirk, LaQue Center for Corrosion Technology, Inc.; T.S. Lee, National Association of Corrosion Engineers; Henry Leidheiser, Jr., Center for Surface and Coa ting Research, Lehigh University; Richard O. Lewis, Department of Materials Science and Engineering, University of Florida; Gene P. Sheldon, Olin Corporation Effects of Alloy Compositions Copper alloys are traditionally classified under the groupings listed in Table 1. Table 1 Generic classification of copper alloys Generic name UNS numbers Composition Wrought alloys Coppers C10100-C15760 >99% Cu High-copper alloys C16200-C19600 >96% Cu Brasses C205-C28580 Cu-Zn Leaded brasses C31200-C38590 Cu-Zn-Pb Tin brasses C40400-C49080 Cu-Zn-Sn-Pb Phosphor bronzes C50100-C52400 Cu-Sn-P Leaded phosphor bronzes C53200-C54800 Cu-Sn-Pb-P Copper-phosphorus and copper-silver-phosphorus alloys C55180-C55284 Cu-P-Ag Aluminum bronzes C60600-C64400 Cu-Al-Ni-Fe-Si-Sn Silicon bronzes C64700-C66100 Cu-Si-Sn Other copper-zinc alloys C66400-C69900 . . . Copper-nickels C70000-C79900 Cu-Ni-Fe Nickel silvers C73200-C79900 Cu-Ni-Zn Cast alloys Coppers C80100-C81100 >99% Cu High-copper alloys C81300-C82800 >94% Cu Red and leaded red brasses C83300-C85800 Cu-Zn-Sn-Pb (75-89% Cu) Yellow and leaded yellow brasses C85200-C85800 Cu-Zn-Sn-Pb (57-74% Cu) Manganese and leaded manganese bronzes C86100-C86800 Cu-Zn-Mn-Fe-Pb Silicon bronzes, silicon brasses C87300 C87900 Cu-Zn-Si Tin bronzes and leaded tin bronzes C90200-C94500 Cu-Sn-Zn-Pb Nickel-tin bronzes C94700-C94900 Cu-Ni-Sn-Sn-Zn-Pb Aluminum bronzes C95200-C95810 Cu-Al-Fe-Ni Copper-nickels C96200-C96800 Cu-Ni-Fe Nickel silvers C97300-C97800 Cu-Ni-Zn-Pb-Sn Leaded coppers C98200-C98800 Cu-Pb Miscellaneous alloys C99300-C99750 . . . Coppers and high-copper alloys have similar corrosion resistance. They have excellent resistance to seawater corrosion and biofouling, but are susceptible to erosion-corrosion at high water velocities. The high-copper alloys are primarily used in applications that require enhanced mechanical performance, often at slightly elevated temperature, with good thermal or electrical conductivity. Processing for increased strength in the high-copper alloys generally improves their resistance to erosion-corrosion. A number of alloys in this category have been developed for electronic applications- -such as contact clips, springs, and lead frames that require specific mechanical properties, relatively high electrical conductivity, and atmospheric-corrosion resistance. Brasses are basically copper-zinc alloys and are the most widely used group of copper alloys. The resistance of brasses to corrosion by aqueous solutions does not change markedly as long as the zinc content does not exceed about 15%; above 15% Zn, dezincification may occur. Quiescent or slowly moving saline solutions, brackish waters, and mildly acidic solutions are environments that often lead to the dezincification of unmodified brasses. Susceptibility to stress-corrosion cracking (SCC) is significantly affected by zinc content; alloys that contain more zinc are more susceptible. Resistance increases substantially as zinc content decreases from 15 to 0%. Stress-corrosion cracking is practically unknown in commercial copper. Elements such as lead, tellurium, beryllium, chromium, phosphorus, and manganese have little or no effect on the corrosion resistance of coppers and binary copper-zinc alloys. These elements are added to enhance such mechanical properties as machinability, strength, and hardness. Tin Brasses. Tin additions significantly increase the corrosion resistance of some brasses, especially resistance to dezincification. Examples of this effect are two tin-bearing brasses: uninhibited admiralty metal (no active UNS number) and naval brass (C46400). Uninhibited admiralty metal was once widely used to make heat-exchanger tubes; it has largely been replaced by inhibited grades of admiralty metal (C44300, C44400, and C44500), which have even greater resistance to dealloying. Admiralty metal is a variation of cartridge brass (C26000) that is produced by adding about 1% Sn to the basic 70Cu-30Zn composition. Similarly, naval brass is the alloy resulting from the addition of 0.75% Sn to the basic 60Cu-40Zn composition of Muntz metal (C28000). Cast brasses for marine use are also modified by the addition of tin, lead, and, sometimes, nickel. This group of alloys is known by various names, including composition bronze, ounce metal, and valve metal. These older designations are used less frequently, because they have been supplanted by alloy numbers under the UNS or Copper Development Association (CDA) system. The cast marine brasses are used for plumbing goods in moderate-performance seawater piping systems or in deck hardware, for which they are subsequently chrome plated. Aluminum Brasses. An important constituent of the corrosion film on a brass that contains a few percent aluminum in addition to copper and zinc is aluminum oxide (Al 2 O 3 ), which markedly increases resistance to impingement attack in turbulent high-velocity saline water. For example, the arsenical aluminum brass C68700 (76Cu-22Zn-2Al) is frequently used for marine condensers and heat exchangers in which impingement attack is likely to pose a serious problem. Aluminum brasses are susceptible to dezincification unless they are inhibited, which is usually done by adding 0.02 to 0.10% As. Inhibited Alloys. Addition of phosphorus, arsenic, or antimony (typically 0.02 to 0.10%) to admiralty metal, naval brass, or aluminum brass effectively produces high resistance to dezincification. Inhibited alloys have been extensively used for such components as condenser tubes, which must accumulate years of continuous service between shutdowns for repair or replacement. Phosphor Bronzes. Addition of tin and phosphorus to copper produces good resistance to flowing seawater and to most nonoxidizing acids except hydrochloric (HCI). Alloys containing 8 to 10% Sn have high resistance to impingement attack. Phosphor bronzes are much less susceptible to SCC than brasses and are similar to copper in resistance to sulfur attack. Tin bronzes alloys of copper and tin tend to be used primarily in the cast form, in which they are modified by further alloy additions of lead, zinc, and nickel. Like the cast brasses, the cast tin bronzes are occasionally identified by older, more colorful names that reflect their historic uses, such as G Bronze, Gun Metal, Navy M Bronze, and steam bronze. Contemporary uses include pumps, valves, gears, and bushings. Wrought tin bronzes are known as phosphor bronzes and find use in high strength wire applications, such as wire rope. This group of alloys has fair resistance to impingement and good resistance to biofouling. Copper Nickels. Alloy C71500 (Cu-30Ni) has the best general resistance to aqueous corrosion of all the commercially important copper alloys, but C70600 (Cu-10Ni) is often selected because it offers good resistance at lower cost. Both of these alloys, although well suited to applications in the chemical industry, have been most extensively used for condenser tubes and heat-exchanger tubes in recirculating steam systems. They are superior to coppers and to other copper alloys in resisting acid solutions and are highly resistant to SCC and impingement corrosion. Nickel Silvers. The two most common nickel silvers are C75200 (65Cu-18Ni-17Zn) and C77000 (55Cu-18Ni-27Zn). They have good resistance to corrosion in both fresh and salt waters. Primarily because their relatively high nickel contents inhibit dezincification, C75200 and C77000 are usually much more resistant to corrosion in saline solutions than brasses of similar copper content. [...]... Additional information on this form of attack is available in the section "Dealloying Corrosion" of the article "Metallurgically Influenced Corrosion" in this Volume Corrosion Fatigue The combined action of corrosion (usually pitting corrosion) and cyclic stress may result in corrosion fatigue cracking Like ordinary fatigue cracks, corrosion fatigue cracks generally propagate at right angles to the maximum tensile... bronze C22000 205 400 1 Cartridge brass C26000 260 500 1 Muntz metal C28000 190 375 Admiralty metal C44300, C44400, C44500 300 575 1 Phosphor bronze, 5 or 10% C51000, C52400 190 375 1 Silicon bronze C65500 370 70 0 1 Aluminum bronze C61300, C61400 400 75 0 1 The exact thermal treatment should be established by examining specific parts for residual stress If such examination indicates that a thermal treatment... acicular crystals, a combination that is often superior in corrosion resistance to the normal annealed structures Iron-rich particles are distributed as small round or rosette particles throughout the structures of aluminum bronzes containing more than about 0.5% Fe These particles sometimes impart a rusty tinge to the surface, but have no known effect on corrosion rates Nickel-aluminum bronzes are more complex... Intergranular corrosion Corrosion along grain boundaries without visible signs of cracking Select proper alloy for environmental conditions based on metallographic examination of corrosion specimens Dealloying Preferential dissolution of zinc or nickel, resulting in a layer of sponge copper Select proper alloy for environmental conditions based on metallographic examination of corrosion specimens Corrosion. .. fluctuating stress and corrosion propagate much more rapidly than cracks caused solely by fluctuating stress Also, corrosion fatigue failure usually involves several parallel cracks, but it is rare for more than one crack to be found in a part that has failed by simple fatigue The cracks shown in Fig 1 are characteristic of service failures resulting from corrosion fatigue Fig 1 Typical corrosion fatigue... high in fatigue limit and resistance to corrosion in the service environment are more likely to have good resistance to corrosion fatigue Alloys frequently used in applications involving both cyclic stress and corrosion include beryllium coppers, phosphor bronzes, aluminum bronzes, and copper nickels More information on corrosion fatigue is available in the section "Corrosion Fatigue" of the article "Mechanically... fairly rapid Select proper alloy based on stress -corrosion tests; reduce applied or residual stress; remove mercury compounds or NH3 from environment General Corrosion General corrosion is the well-distributed attack of an entire surface with little or no localized penetration It is the least damaging of all forms of attack General corrosion is the only form of corrosion for which weight loss data can be... significance: E, excellent: resists corrosion under almost all conditions of service G, good: some corrosion will take place, but satisfactory service can be expected under all but the most severe conditions F, fair: corrosion rates are higher than for the G classification, but the metal can be used if needed for a property other than corrosion resistance and if either the amount of corrosion does not cause excessive... identifying characteristics of the forms of corrosion that commonly attack copper metals as well as the most effective means of combating each Table 2 Guide to corrosion of copper alloys Form of attack Characteristics Preventive measures General thinning Uniform metal removal Select proper alloy for environmental conditions based on weight loss data Galvanic corrosion Corrosion preferentially near a more... "General Corrosion" in this Volume Galvanic Corrosion An electrochemical potential almost always exists between two dissimilar metals when they are immersed in a conductive solution If two dissimilar metals are in electrical contact with each other and immersed in a conductive solution, a potential results that enhances the corrosion of the more electronegative member of the couple (the anode) and partly . Conference on Corrosion of Military Equipment, Technical Report AFML-TR -75 -42, Vol II, 1 972 , p 193 79 . S.J. Ketcham and P.W. Jeffrey, Exfoliation Corrosion Testing of 71 78 and 70 75 Aluminum Alloys,. SCC and impingement corrosion. Nickel Silvers. The two most common nickel silvers are C75200 (65Cu-18Ni-17Zn) and C 770 00 (55Cu-18Ni-27Zn). They have good resistance to corrosion in both fresh. 19 67, p 389 104. K.G. Compton, Seawater Tests, in Handbook on Corrosion Testing and Evaluation, W.H. Ailor, Ed., John Wiley & Sons, 1 971 , p 5 07 105. W.K. Boyd and F.W. Fink, "Corrosion