Rain
The chemical composition of rainwater depends on the atmosphere. It has been calculated that 1 l of rainwater collected at an altitude of 1000 m will wash out 326 m3 of air and Figure C.2.3. Influence of deposit and surface condition 1 microcracks, 2 dust, 3 porous corrosion product 5 . Figure C.2.3. Influence of deposit and surface condition 1 microcracks, 2 dust, 3 porous corrosion product 5 . dissolve gaseous pollutants and soluble dust constituents present in the atmosphere. Rainwater thus...
Halide salts
Halide salts chlorides, fluorides, bromides, and iodides are generally more aggressive towards aluminium than sulphates and phosphates. Their aggressiveness decreases in the order given. 1 The term salt, used for these compounds since the 14th century, first by alchemists, stems from the analogy of their appearance and certain properties, such as their solubility in water, with salt NaCl. Oxidising salts such as chlorates, persulphates, nitrates, and perchlorates generally have no action,...
Info Ulp
2 Testing stations in the United States. 2 Testing stations in the United States. Table C.5.4. Alloy 3003 marine atmosphere Pitting depth pm Duration of - Alloy Temper Year of exposure exposure 3003 H14 1932 20 Point Judith 200 75 H14 1935 20 Key West 120 25 Table C.5.5. Series 5000 marine atmosphere Pitting depth pm Duration of - Alloy Temper Year of exposure exposure years Site Maximum Minimum Alloy Temper Year of exposure exposure years Site Maximum Minimum
Derivatives Of Aromatic Hydrocarbons
- Dichlorobenzene C6H4Cl2 1591 - Trichlorobenzene, liquid C6H3Cl3 2321 - Hexachlorobenzene C6Cl6 2729 - Benzylchloride C6H5CH2Cl 1738 - Benzylidene chloride C6H5CHCl2 1886 Chlorine atoms bonded to the benzene ring as in chlorobenzene C6H5C are much less reactive than those bonded to a side-chain as in benzylchloride C6H5CH2Cl . Chlorine derivatives of benzene such as chlorobenzene C6H5Cl, dichlorobenzene C6H4Cl2, trichlorobenzene C6H3Cl3, and hexachlorobenzene C6Cl6 are solvents, intermediates...
Ethers
Ethers of the general formula R4-O-R2 are chemically rather inactive compounds that have many applications solvents, plasticisers, paints, lubricants, brake fluids, dielectric fluids, drugs, perfumes. Most ethers are liquid at room temperature. The first ethers are gaseous. - Dimethyl ether dimethyl oxide CH3 2O 1033 - Diethyl ether diethyl oxide C2H5 2O 1155 - Di-n-propyl ether dipropyl oxide C3H7 2O 2384 - Diisopropyl ether diisopropyl oxide CH3 2CH 2O 1159 - Dibutyl ether dibutyl oxide C4H9...
Blackening Of Aluminium
Blackening is not a form of corrosion it is only an alteration of the visual properties of the outmost oxide layer 6 . It does not alter the corrosion resistance of aluminium in water. This unavoidable phenomenon has been observed since kitchen utensils made of aluminium began to be used 7 . To prevent blackening, it used to be recommended to boil milk in the utensils prior to their first use 8 . This old recipe is only somewhat effective. Blackening is not irreversible and can disappear in...
The Influence Of Water Movement And Flow Speed
Based on experience, it is known that the corrosion resistance of aluminium in moving or frequently replaced water is always better than in stagnant water, if all the other parameters are kept constant. Tests over 1 week in freshwater at 20 C have shown that the density and depth of pitting decreases with increasing flow speed Table D.1.6 33 . Water movement regularly eliminates corrosion products and uniformises the cathodic and anodic zones by removing a possible local excess of H and OH...
The Influence Of Temperature
Temperature has a very important influence on the corrosion resistance of aluminium in freshwater, whether natural or distilled. The same applies to seawater. Several temperature domains corresponding to different forms of corrosion need to be distinguished. Their limits are not defined strictly, but may depend on the composition and the nature of the water. 1.7.1. Reactions of natural oxide films with water The corrosion resistance of aluminium in water depends on the reaction of the natural...
REFERENCES Kaj
1 Leyerzapf H., Formic acid. Corrosion Handbook, vol. 4, Dechema, 1989. 2 Zaritskii V.I.D., Corrosion and strenght behavior of aluminium in the formic acid-water system, Fisiko Khimicheskaya Mekhanika Materialov, no 2, 1990, p. 110-113. 3 Eisner G., Acetic acid. Corrosion Handbook, vol. 6, Dechema, 1990. 4 Swandby R.K., Corrosion charts. Guides to materials selection, Chemical and Engineering, vol. 69, 1962, p. 186. 5 Skvortsov I.I., An investigation of the corrosion resistance of welded...
Info Lfa
In non-industrial urban areas, sulphur dioxide emissions are much higher during winter than in summer. Over a long period, the sulphur dioxide concentration has decreased Figure C.2.8 because of the anti-pollution policies, the evolution of the industrial structure resulting in the disappearance of heavy industries, and energy saving. Sulphur dioxide is highly soluble in water Table C.2.4 and dissolves easily in the moisture film present on the surface of the metal. With water, it forms...
Sulphur S
Unlike other common metals, aluminium does not react with sulphur to yield sulphides, even at high temperatures. Aluminium is thus inert in contact with sulphur over a wide range of temperatures, whether solid or liquid melting point 119 C . Tests have confirmed that aluminium is totally inert in contact with vapours of boiling sulphur at 444 C. Aluminium equipment is widely used in the sulphur industry, for mining, storage and transportation. Table E.3.1. Dissolution rate in a solution...
Chemical Conversion Treatments
Chemical conversion treatments form a thin, complex oxide layer which may reach 0.050.15 m. The formation of these complex oxides may be obtained in acidic or alkaline phosphate or chromate baths 4 . As in the case of boehmite formation, the chromate treatment starts at grain boundaries 5 . These treatments are mainly used for forming a base layer for paints, lacquers and adhesives. They slightly increase the corrosion resistance of aluminium. There are two types of chemical conversion...
Aromatic Alcohols
- Alpha-methylbenzyl alcohol C8H9OH 2937 - phenylethyl alcohol C6H5C2H4OH, - phenylbutyl alcohol C6H5C2H8OH, - phenylpropyl alcohol C6H5C3H6OH, - veratryl alcohol CH3O 2C6H3CH2OH, - anisic alcohol CH3O C6H4CH2OH, Like saturated acyclic alcohols, aromatic alcohols, which are widely used in perfumery, have no action on aluminium, neither pure nor as mixtures or in solution with other organic solvents. They can be stored and transported in aluminium vessels. - Furfuryl alcohol C4H3OCH2OH 2874...
REFERENCES Kic
1 Zotikov V.S., Semenyuk E.Y., Corrosion of metals in ammonium fluoride solutions, Tr Gos. In-Ta Prikl. Khim, vol. 67, 1971, p. 199. 2 Kawakatsu I., Osawa T., Erosion of aluminium based alloys by molten brazing flux, Journal of Japan Institute of Metals, vol. 37, 1977, p. 435. 3 Herenguel J., Scheidecker M., Lelong P., Biais R., Boghen R., Whitwham D., Aluminium et magnesium en energie nucleaire, Revue de l'Aluminium, no. 334, 1965, p. 989-997. 4 Saninger J.M., Alba F., Garrido S.J., Avendano...
Info Utb
More recent tests up to a depth of 5000 m in the Atlantic Ocean 16 and up to 3000 m in the Indian Ocean 17 have shown that the corrosion resistance of aluminium does not depend on the immersion depth. Several exploration devices have been made of aluminium such as the Aluminaut made in 7079 T6 18 . The presence of abundant deposits of organic or inorganic sediments could be expected to have an influence on the corrosion resistance of certain metals and alloys, because of the release of sulphur...
ASTM G Tef
Measurement of ASTM G 69 dissolution potentials Standard test method for performing a stress corrosion cracking test of low copper containing Al-Zn-Mg alloys in boiling 6 sodium chloride solution Standard practice for alternate immersion stress-corrosion testing in 3-5 sodium chloride solutions. Standard test method for determining susceptibility to stress-corrosion cracking of high-strength aluminium alloy products. Standard classification of resistance to stress-corrosion cracking of...
Thiols And Their Derivatives
Thioalcohols, also called mercaptans, correspond to the general formula R-S-H. The most common ones are Mercaptans have no action on aluminium, even at high temperatures. Certain of their derivatives are prepared at elevated temperatures in reactor vessels made of aluminium alloy. An example is sulphonal, which does not attack aluminium at 125 C. Thiophenols, like mercaptans, have no action on aluminium. Benzyl sulphide C6H5CH2 2S is a corrosion inhibitor for aluminium in acid medium....
Stress corrosion criteria
The propagation rate of stress corrosion cracks is very low, between 10_6 and 10_11 m-s_1. However, propagation, even at this low rate, may lead to catastrophic mechanical failure, due to the weakening of the structures. By analogy with failure mechanics, two criteria can be determined for assessing the susceptibility to stress corrosion of aluminium alloys - the limit of susceptibility to stress corrosion, which depends both on the alloy and the sampling direction Figure B.2.14 , - the...
Hydrogen Nitrogen and Noble Gases 1
- Liquid cooled hydrogen 1966 . Gaseous or liquid hydrogen does not interact with aluminium at any pressure. Due to their very good resistance at low temperatures, aluminium alloys have interesting applications in installations for the cooling, compression and liquefaction of this gas, as well as for the construction of reservoirs for liquid hydrogen in rockets 1 . Hydrogen is highly soluble in liquid aluminium, but insoluble in the solid state Figure E.2.1 . Figure E.2.1. Solubility of...
REFERENCES Btx
1 Altenpohl D.G., Use of boehmite films for corrosion protection of aluminium, Corrosion, vol. 18, 1962, p. 143t-153t. 2 Hart R.K., The formation of films on aluminium immersed in water, Transaction of the Faraday Society, vol. 53, 1956, p. 1020-1027. 3 Uchiyama T., Hasegawa M., Matsumoto H., A study on chemical conversion coating formed on aluminium in boiling sea water, Journal of Metals Finishing Society Japan, vol. 37, 1986, p. 28-33. 4 Koudelkhova M., Augusynski J., Berthou H., On the...
Butyrates
methyl butyrate C3H7CO2CH3, ethyl butyrate C3H7CO2C2H5, propyl butyrate C3H7CO2C3H7, butyl butyrate C3H7CO2C4H7, amyl butyrate C3H7CO2C5Hn, - cyclohexyl butyrate C3H7CO2C6H11, - geranyl butyrate also called bornyl butyrate C3H7CO2C10H17, - citronellyl butyrate C3H7CO2C10H19, - glycol butyrate C3H7CO2C2H4OH Equipment in aluminium such as reaction vessels, heat exchangers and condensers is used for the fabrication, storage and packaging of these products, which do not suffer any alteration in...
Pitting probability
Figure B.2.6. Gumbel plot pitting depth in marine atmosphere testing over 2 years . In addition to the pitting penetration rate, it is also possible to characterise pitting corrosion on aluminium by means of the probability, which is defined as Np is the number of specimens exhibiting pitting, N is the number of exposed specimens. A large number of specimens are required for the reliable assessment of this parameter. Pitting probability and penetration rate are two concepts that characterise...
REFERENCES Evq
1 Rey A., dir. , Dictionnaire historique de la langue fran aise, Le Robert, Paris, 1993. 2 Lynes W., Some historical developments relating to corrosion, Journal of the Electrochemical Society, vol. 98, 1951, p. 3c-10c. 3 Hoar T.P., Evans U.R., Quantitative confirmation of electrochemical theory of corrosion of iron, Proceeding of Royal Society of London, vol. 137, 1932, p. 343. 4 Smith C.A., The corrosion story. Part 3, Zinc, lead and aluminum, Anti-Corrosion, vol. 24, 1977, p. 13-15. 5 Crolet...
The Electrochemical Reactions In The Corrosion Of Aluminium
The fundamental reactions of the corrosion of aluminium in aqueous medium have been the subject of many studies 7, 8 . In simplified terms, the oxidation of aluminium in water proceeds according to the equation Metallic aluminium, in oxidation state 0, goes in solution as trivalent cation Al3 when losing three electrons. This reaction is balanced by a simultaneous reduction in ions present in the solution, which capture the released electrons. In common aqueous media with a pH close to neutral...
REFERENCES Hxj
1 McKee A.B., Brown R.H., Resistance of aluminium to corrosion in solutions containing various anions and cathions, Corrosion, vol. 3, 1947, p. 595-612. 2 Patrie J., Les phenomenes de passivation de l'aluminium immerge en milieu nitrique, Revue de l'Aluminium, vol. 194, 1952, p. 96, see also vol. 195, p. 5-11, vol. 196, p. 45-54 and vol. 197, p. 87-96. 3 Whitaker M., A review of information on the effect of impurities on the corrosion resistance of aluminium, Metal Industry, vol. 80, 1952, p....
Applications Of Aluminium In Contact With Foodstuffs
Aluminium is used in the food industry either in food processing equipment vats, trays, kitchen utensils, cutting equipment, mixers, etc. or in packaging. In packaging, aluminium can be - protected by a lacquer or a plastic film. The lacquer thickness varies between 5 and 15 m depending on the nature of the foodstuff. It aims at protecting aluminium against prolonged action of aggressive foodstuffs such as tomato ketchup. In practice, most cans for fruit juice, beer, sodas beverage cans , etc....
Anodising
The idea to thicken the natural oxide layer was first mentioned by Buff in 1857 17 . He had observed that aluminium became covered with an oxide film when placed in the anodic position in electrolysis cells. This idea was taken up at the beginning of the 20th century, and a first patent was filed in 1911 by the Frenchman de Saint-Martin, who proposed an anodising process in a sulphuric medium containing iron sulphate. Several processes and variants thereof have been developed since 1923 -...
Definition Of Galvanic Corrosion
When two dissimilar metals are in direct contact in a conducting liquid, experience shows that one of the two may corrode. This is called galvanic corrosion.1 The other metal will not corrode it may even be protected in this way. This corrosion is different in its kind and intensity from the one that would occur if they were placed separately in the same liquid. Unlike other types of structural corrosion, galvanic corrosion does not depend on the metal's texture, temper, etc. Galvanic corrosion...
Alloys with silicon series
These alloys are easy to cast because their eutectic temperature is 575 C. Most aluminium casting alloys are alloys with silicon 40000 series . They are divided into two categories - copper-containing alloys, which are used only in the automotive industry. They are beyond the scope of this book. Due to their high copper content, their resistance to corrosion is rather low . 44100 A-S13 , formerly called Alpax, These alloys have many applications as structural components in mechanical...
Water Line Corrosion
Experience has shown that when metallic structures are partly immersed in water, a localised and more intense corrosion very often occurs on the immersed portion just below the air-water interface Figure B.2.19 . This is caused by the difference in aeration between the surface of the liquid and the zone immediately underneath. This differential aeration was shown by Evans in the following experiment a container with an alkaline solution is subdivided into two parts of equal volume by means of a...
pH value
According to the theory of S. Arrhenius, the electrical conductivity of pure water results from dissociation of part of its molecules 10 7 at 25 C according to the equilibrium By definition pH log H , and pH values thus range from 0 to 14 Table B.6.1 . The pH is a characteristic value for aqueous media. In chemistry, electrochemistry and biology, this is a very important parameter because it helps understand reactions in aqueous media. The pH value is involved in the precipitation of hydroxides...
Microbiological Corrosion
Microbiological corrosion of a metal may be caused by - heterotrophic bacteria that require an organic carbon source in order to develop. They can assimilate a wide range of organic substances, transforming them into carbon dioxide, metabolites and organic acids, which are released in the nearby environment. It is this modification of the environment not the bacteria themselves which leads to corrosion - autotrophic bacteria, which develop only in the presence of inorganic elements, while...
Info Hky
This page is intentionally left blank Organic acids are of the general formula and form a product family with many applications they are used in the production of polymers, resins, dyestuffs, detergents, pharmaceuticals, sweeteners, etc. Several of them belong to the fifty most important chemicals produced in the United States, according to a ranking established in 1990 terephthalic acid rank 23 , acetic acid rank 34 , adipic acid rank 46 , and isopropyl acid rank 48 . They are weak acids and...
Aromatic esters
- citronellyl benzoate C6H5CO2C10H19 are used in perfumery and pharmaceutical products. They have no action on aluminium, which is used for the storage and bottling of these esters. The same applies to esters such as - anisyl formate HCO2-C6H4OCH3, - anisyle acetate CH3CO2-C6H4OCH3 - benzyl acetate CH3CO2-CH2C6H5, - methyl naphthenates C10H7OCH3, - ethyl naphhtenates Ci0H7OC2H5, - butyl naphthenates Ci0H7OC6H5. Waxes mainly contain esters of higher monocarboxylic acids and higher monoalcohols....
Other esters
- methyl methacrylate C3H5CO2CH3, - ethyl methacrylate C3H5O2CC2H5, - propyl methacrylate C3H5CO2C3H7, - butyl methacrylate C3H5CO2C4H9 are used as plasticisers in the formulation of lacquers and resins. They have no action on aluminium. They can be stored and transported in aluminium vessels. Esters of acid alcohols and diacids such as methyl lactates C3H5CO2CH3, ethyl lactates C3H5CO2C2H5, butyl lactates C3H5CO2C4H9, ethyl adipates C3H5CO2C2H5, butyl adipates C3H5CO2C4H9, amyl adipates...
Cavitation
Cavitation occurs when the hydrodynamic pressure exceeds the vapour pressure of a moving liquid. Gas bubbles form within the liquid, which thus becomes a two-phase system. These bubbles will be crushed against the metal surface at high speed, an attack that leads to cavities with rounded contours. This degradation is caused by the combination of a mechanical effect and corrosion of the metal. The natural oxide film is destroyed and the aluminium is attacked there is a competition between...
Aluminium As A Passive Metal
Aluminium is naturally passive and, therefore, does not need to be passivated, unlike certain metals such as steel. A metal that can be passivated has undergone a chemical treatment or contains an alloying element, which renders it passive against the medium. It can be depassivated, or may not have been passivated. This does not apply to aluminium, which is of course always covered by its natural oxide layer. The dissolution potential of aluminium in most aqueous media is in the order of 500 mV...
REFERENCES Uom
1 Amine und Aminierung, Dechema Werkstofftabelle, Mai 1953. 2 Buckowiecki A., Untersuchungen ber das Korrosionsverhalten von Aluminium und Aluminiumlegierungen gegenuber organischen und anorganischen Basen, Werkstoffe und Korrosion, vol. 10, 1959, p. 91-105. 3 Riesenfeld F.C., Hughes C.I., Corrosion in amine gas-treating plants, Petroleum Refiner, vol. 30, 1951, p. 97-106. 4 Riesenfeld F.C., Blohm C.L., Corrosion resistance of alloys in amine gas-treating systems, Petroleum Refiner, vol. 30,...
Stainless steel
Although there is a great difference in potential between stainless steel and aluminium alloys, in the order of 650 mV, it is unusual to see galvanic corrosion on aluminium in contact with stainless steel. Aluminium alloy components are often assembled using stainless steel bolts, e.g. in metallic fittings. 3.8.4. Copper and copper alloys While contact between aluminium alloys and copper and cuprous alloys bronze, brass causes no appreciable galvanic corrosion of aluminium under atmospheric...
Boehmite Coatings
Boehmite 7-AlOOH coatings are natural oxide coatings formed by the reaction with water at a temperature of at least 75 C according to the reaction Boehmite formation starts at grain boundaries and then advances to the surface. The conditions of boehmite film growth in water or vapour have been studied by Altenpohl 1 . Boehmite coatings are grown by a prolonged contact, on the order of a few hours, with vapour of deionised water at a temperature between 110 and 160 C, depending on the purity of...
Phenols
Phenols, of the general formula ArOH where Ar is a group including one or more benzenic rings , are solids at room temperature. They are water soluble, and their solubility decreases very rapidly as their molecular weight increases. Aqueous phenol solutions are slightly acidic, because of the OH group. For example, a phenol C6H5OH solution has a pH close to 6. They are used as disinfectants, additives to tanning solutions, intermediates in the synthesis of dyestuffs, and in the fabrication of...
Info Orh
0.0 0.1 1 10 100 Duration of artificial ageing hours Figure B.1.9. Influence of the duration of ageing treatment on the dissolution potential of alloys 2014 and 7075 17 . Pourbaix diagrams cover several domains representing three possible situations - Corrosion, where a soluble corrosion product exists. Pourbaix has defined a concentration of 106 M which amounts to 0.027 mg-l_1 for aluminium as a lower threshold above which it can be assumed that corrosion takes place. On most of these...
Info Xcl
- Propyl alcohol, normal n-propanol C3H7OH 1274 - Isopropyl alcohol isopropanol C3H7OH 1219 - Isobutyl alcohol isobutanol C4H9OH 1212 - Pentanols amyl alcohols C5HnOH 1105 The most common alcohols, which are liquids up to Cn or solids beyond - pentyl alcohol or amyl alcohol C5H11OH, - octyl alcohol or capryl alcohol C8H17OH, - dodecyl alcohol or lauryl alcohol Ci2H25OH, - tetradecyl alcohol or myristyl alcohol Ci4H29OH, - hexadecyl alchol or cetyl alcohol C16H33OH, - octadecyl alcohol or...
Aromatic Aldehydes
- phenylacetic aldehyde C6H5CH2CHO, - vanillic aldehyde vanillin CH3OC6H3 OH CHO, - salicylic aldehyde HOC6H4CHO, - cinnamic aldehyde C6H5 C2H2 CHO, - coumaric aldehyde OHC6H4C2H2CHO, - cumenic aldehyde CH3 2CHC6H4CHO, - anisic aldehyde C6H4 OCH3 CHO, - veratric aldehyde CH3O 2C6H3CHO, - terephthalic aldehyde C6H4 CHO 2 are very widely used for cosmetics and perfumery. They have no action on aluminium. Aluminium equipment is used for the production, transportation, storage and packaging of...
Corrosion Products
According to the basic corrosion reaction of aluminium the corrosion product is aluminium hydroxide Al OH 3, commonly called alumina. Freshly formed alumina contains a great deal of water. After calcination at 1000 C, the mass loss can reach 60 47 . Alumina is a gelatinous white gel that covers corrosion pits. After several weeks of exposure to air, part of the water will evaporate and the alumina will look like a white powder. Whether dry or not, the alumina adheres well to the metal surface....
Action on aluminium Gkm
Acridine C6H4CH-N-C6H4 which is the starting compound for the synthesis of certain dyestuffs , - coumarin or 1,2-benzopyrone , - furan C4H4O and its derivatives such as furfural C5H4O2, - indole C8H7N or benzopyrrole , - nicotine C10H14N2 and its derivatives such as nicotine acid or nicotine sulphate, - morphine Ci7H19NO3 and its derivatives such as codeine, - picolines C6H7N and their numerous derivatives used in perfumery, - thiophene C4H4S and its derivatives, whether concentrated or in...
Nitrogen
- Nitrogen, refrigerated liquid 1977 Gaseous or liquid nitrogen does not interact with aluminium at any pressure. 2.3. NOBLE GASES ARGON Ar, HELIUM He, KRYPTON Kr, NEON Ne, AND XENON Xe - Argon, refrigerated liquid 1951 - Helium, refrigerated liquid 1963 - Krypton, refrigerated liquid 1970 - Neon, refrigerated liquid 1913 - Xenon, non-refrigerated liquid 2036 - Xenon, refrigerated liquid 2591 . These gases are chemically inert. Therefore, they have no action on aluminium, whatever the pressure...
Dissolution Potentials
Standard electrode potentials measured with respect to hydrogen are only of theoretical interest. They are relevant only to pure metals, not to alloys, and do not take into account possible passivation phenomena, as can be seen in the case of aluminium. They are measured in a very peculiar medium, namely a standard solution of the salt of the metal under consideration. They are only of limited interest for corrosion experts, who prefer dissolution potentials or corrosion potentials , which are...
Action on aluminium Xam
Ammonium chloride solutions NH4Cl lead to slight pitting corrosion at room temperature. Corrosion is much stronger in concentrated, boiling solutions. Lithium chloride LiCl, whether in the solid state or in solution, has an action similar to that of sodium chloride. Barium chloride solutions BaCl2 have only a slight action, comparable to that of calcium chloride. Tests in solutions at 1-10 on 1050 have shown that up to 50 C, the dissolution rate is below 0.03 mm per year at 98 C, it is in the...
REFERENCES Dal
1 Trethewey K.R., Sargeant D.A., The galvanic effect a continuing corrosion problem, Metals and Materials, vol. 8, 1992, p. 378-382. 2 Vargel C., La corrosion des bateaux en aluminium, Loisirs Nautiques, nos 241, 1991, p. 16-24. 3 Toy S.M., English W.D., Crane W.E., Studies of galvanic corrosion couples in liquid fluorine, Corrosion, vol. 24, 1968, p. 418-421. 4 Oldfield J.W., Electrochemical theory of galvanic corrosion, ASTM, STP 978, 1988, p. 5-22. 5 Mansfeld F., Henkel J.V., Galvanic...