INDUSTRIAL AND ENGINEERING CHEMISTRY
1970
(44) Klinefelter, T. A,, Hancoek, R. T., and Hamlin, H. P., Ibid., pp. 294-96. (45) Knight, Maurice A., Jr., personal communication (April 12, 1950). (46) Koenig, J. H., IND.ENQ.CHEM.,41,2106 (1949). (47) Kreidl, N. J., Qlasslnd., 31, 13841 (1950). (48) Lambertson, W. A,, J . Am. Ceram. SOC.,to be published. (49) Lustrell, C. B., Ibid., 32,327-32 (1949). (50) McCann, S. W., Ohio State U n b . Eng. Ezpt. Station News, 19,No. 4,8-12 (October 1947). (51) McLaughlin, J. L.,Ibid., 21, No.2, 6 (1950). (52) McMullen, J. C.,and Thompson, A. P., Am. Ceram. Soc. Bull., 29, la15 (1950). (53) Malcolm, D.H., Belter EnzmeE., 20,No.8,6 (1949). Finish, 6,No. 9,29 (1949). (54) Malcolm, D.H., (55) Marbaker, E.E., Ibid., KO.12,p. 8. (56) Millar, N. S.C., Inst. of Vit. Enamel. Conf., Birmingham, England, Oct. 6,1949. (57) Minnick, L. J., and Bauer, W. H., A m . Ceram. SOC.Bull., 29, 177-80 (1950). (58) Monaok, A. J., Elee. M j g . , February 1947, 11 pp. (59) Moore, D. G., Boltz, L. H., and Harrison, W. N., Natl. Advisory Comm. AeroPuLutw, Tech. Note 1626 (1949). (60) Norton, F. H., J. Am. Ceram. SOC.,30,242-5 (1947). (61) Patrick, R. F.,Ibid., to be published. (62) Ralston, 0. C., U.S. BUT.Mines, Inform. Circ. 7364 (August 1946). (63) Redmond, J. C.,and Smith, E. N., Trans. Am. Inst. Mining Met. Engrs., 185,987-93 (1949). (6-1) Riddle, Frank H., J . Am. Ceram. S O C . , 32,333-46 (1949).
Vol. 42, No. 10
(65) Rochow, N. F.,Cemm. I d . , 53,No. 3,66 (1949). (66) Rothermel, J. J., Sun, K-H, and Silverman, .4,,J . Am. Ceram. SOC..32, 153-62 (1949). (67) Ruh, Edwin, Ceram. Age, 55, No. 4,236 (1950). (68)Scholes, W. A., J . Am. Ceram. SOC.,33, 111-17 (1950). (69) Shand, E. B., Corning Glass Works, Corning, N. Y., personal communication (June 27, 1950). (70) Shand, E. B., “Heating and Ventilating,” to be published. (71) Shand, E.B., IND.ENO.CHEM.,41,2107 (1949). (72) Shevlin, T. S., and Blackburn, A. R., J . Am. Ceram. SOC.,32, 363-6 (1949). (73) Simpson, H.E.,Ceram. Znd., 54,No.2,55 (1950). (74) Sirow, G., and Czolgos, E. P., Am. Cwam. SOC.Bull., 28,2234 (1949). (75) Smoke, E.J., Ceram. Age, 51,No.3, 115-16 (1948). (76)Ibid., 54, NO.3, 148-9 (1949). (77)Ibid., to be published. (78) Smoke, E. J., J . A m . Ceram. SOC.,33, 174-7 (1950). (79) Smoke, E. J . , Ibid., to be published. (80) Spencer-Strong, G. H., Am. Ceram. 80c. Bull., 28,183-6 (1949). (81) Spencer-Strong, G.H., and Patrick, R. F.,IND. ENG.CHEM., 42, 253 (1950). Steinberg, E. B., Elec. Mfg., November 1949. Thurnauer, H., Ceram. Ind., 29,362 (1937). (84) Weaver, R. A.,Finish, 7,No.4,42 (1950). (85)Whittemore, 0.J., Jr., .f. Am. Ceram. SOC.,32,48-53 ( l ~ r ~ ) . (86) Wisely, H. R., Ibid., to be published. (87) Witt, L., and King, R. M., Finish, 7,No.1, 28 (1950). RECEIVED Jrily 17, 19.50
Wrought Copper and Copper-Base Alloys c. L.
BULOW,
Bridgeport
Brass Company, Bridgeport, Conn.
A
NUMBER of revisions in the A.S.T.M. specifications cover-
ing copper and copper alloy, tubes, plates, sheets, rods, bars, and shapes were made during the past year. The revised specifications are: B75-49T, B96-49, B98-49, Bill-49 and B171-49. During the past year, several groups (‘4.97, 119) issued technical publications containing much information regarding the physical, mechanical, and fabrication properties and uses of copper and copper alloys. These publications are available at no cost. Klement (87) describes the use of alununum-bronze dies for deep drawing stainless steel in order to obtain good surface finishes. It is reported that aluminum-bronze dies are not subject to abrasion, scoring, or seizing. Ihrdyumov and Khandros (91 ) studied the martensitic transformation in an aluminum bronze containing 14.5% aluminum and from 1 to 1.5% nickel. Klier arid Grymko (88) studied the transformations taking place in thc beta phase of aluminum bronze. Improved machinabilit,y in 10% aluminum bronze was reported by Grodsky (69) by the addition of 1%of lead. It was also reported that this alloy responded to heat treatment in a greater degree than bronzes containing from 2 to 3y0 of lead. The mechanical proprrt,ies of this aluminum bronze diffwc:d little from the usual properties of the eame type alloy containing no lead. A patent on hrat t~reatingaluminum bronzes by Grange (67) reveals that t.his treatment increases the cast. hardness of 140 Brinell up to 302 to 320 Brinell after quenching, with a further increase up t o 400 Brinell after drawing. These hardness values are obtained in a heat-treatable aluminum bronze containing 12.4% aluminum, 3.5% iron, 3.5% nickel, and the balance copper. A inodified aluminum bronze containing zinc and manganese is
described in a patent by Berwick (17). Bearings made of this alloy are said to have low frictional resistance combined with long wearing qualities. Flussfisch (66)in a Swiss patent describes an aluminum bronze containing from 2 to 5% of gold and up t o 3% of palladium for replacing gold plating; i t is suitable for bracelets and watch cases. A process has been developed for making uniformly spherical copper shot for use in blast cleaning and shot peening operations. It is believed that this material may also be suitable for use in chemical industries either aa a catalyst or in the formation of filter bcds. This material is said to be available in commercial quantity in screen sizes ranging from 1.7 up to 66.1 mils in phosphorus deoxidized electrolytic copper (1). The availability of a new forged copper ball anode t o replace the old type cast copper ball has been announced (145). It is claimed that these forged anodes result in finer and more even grain, purer anode, and cleaner plating. Raker and Hallowes (fa)have found that the brittleness in phosphorus deoxidized copper containing 0.005 to 0.01% bismuth can be eliminated by the addition of 0.005 to 0.03% lithium, through the formulation of an insoluble intermetallic compound BiLia. Scheil and Schessl (130) studied the diffusion of liquid bismuth along the grain boundaries in copper in an atmosphere of hydrogen over the temperature range 400” to 700” C. An equation was derived which described the velocity of penetration by the bismuth. This same phenomenon was also studied by K& (83). The distribution of bismuth in copper was studied microscopically by Samuels (186). It wm found that the dark lines a t grain boundaries of electrolytically polished brittle copper strips were steplike grooves. Deep
October l9so
INDUSTRIAL AND ENGINEERING CHEMISTRY
cstched grooves also developed a t the grain boundaries in copper containing 0.005 to 0.015% bismuth. The brittleness of copper of this composition was attributed to a brittle zone resulting from the concentration without precipitation of bismuth along the grain boundaries. A metallographic investigation of sintered copper-lead alloy was conducted by Lichtenberg-Strunk and Wiemer (100). Regardless of the amount and type of lead addition, after sintering at 400" C., the structure appeared dense with the lead filling the voids. After sintering at 600' C., copper showed a grain growth and the lead phase became considerably coarser. Morns (108) obtained a patent on a high strength high electrical conductivity alloy containing 2% iron, 1% cadmium, and 97% copper. This alloy is described as having a tensile strength of 90,OOO pounds per square inch with an electrical conductivity of 65.5% and aa being suitable for electrical transmission lines and trolley wire. The properties of copper-silver alloys containing from 4 to 7% silver have been described by Hodge and Rose (76). These alloys have high electrical conductivity and tensile strength, with good ductility and spring characteristics, and are age-hardenable. The high electrical Conductivity makes theae alloys of particular usefulness in the electrical industry. Mabb (104) discussed a number of heat-treatable copper-base alloys, such as aluminum-bronze, beryllium-copper, chromiumcopper, copper-nickel-aluminum-zinc, and copper-manganese nickel alloys. The heat treating procedure, pickling and fabrication, and applications were reviewed. The metallurgy of tin bronzes waa discuesed by Lepp (96). Kurdyumov and Khandros (99)described the characteristics of 25% tin bronze. Anderson and Jillson (S, 8) have obtained patents on two manganese brasses containing ementially from 55 to 72% oopper, 10 to 25% zinc, and 7 to 31% manganese. One manufacturer (6)has announced the availability of heat resistant nickelclad copper wires which provide good electrical conductivity through the copper core combined with heat and corrosion resistance through the nickel sheath. This bimetallic wire is being made in sizes ranging from 5 to 10 mils in diameter of which 27 to 29% is nickel. A series of patents by Chace (81) described the manufacture of bimetallio thermostats where the section having the low coefficient of expansion consists of one of the various high carbon stainleas irons, and the high coefficient of expansion section colisists of one of the various copper-silicon alloys. The two components have sufficiently similar physical properties to permit direct bonding and subsequent hot or cold rolling. A manufacturer's technical bulletin has been released describing duplex tubing (26). This ten-page bulletin describes a large number of combinations of copper and copper alloys with tin, lead, low carbon steel, alloy steels, stainless steel, and aluminum, either as cladding or lining materials for use in many types of condensers and heat cxchangers. MECHANICAL ANI) PHYSICAL PROPERTIES
Iieicherta and Farnsworth (118) studied the inelastic scattering of low speed electrons from a single copper crystal. The radiation intensities emitted by Cuo1 and Cue6 were determined by Bouchez and Kayas ($6). Some observations by Bloenbergen (20) on the magnetic resonance of the copper isotopes Cues and Cu65 between 1" and 20" K. revealed that the relaxation time waa inversely proportional to the temperature. Lesage, Rogozinski, and Voisin ($6)have given complete details on the construction of a metallic Geiger-Miiller counter. The outer envelope is made of brass b r a h g , tin solder, and glass; metal seals were used to make the units vacuum-tight. The usual argon-alcohol mixture is used for filling. The surface energy of copper and a number of other metals was calculated by Fricke (56). The surface energy of solid metals calculated from the heat of sublimation and extrapqlated t o the melting point was compared with directly determined surface tensions of liquid metals also extrapolated to the melting
1971
point. The surface tension for the liquid metal is from 30 to 70% of the surface tension calculated for the solids. Huang and Wyllie (78) reported the surface energy and strength of the surPace layers of copper and a number of other metals. The interface energies in some copper and aluminum alloys containing a liquid phase have been studied by Ikeye and Smith (79). The work functions and aging characteristics of fourteen copper surfaces were determined by Anderson ( 4 ) through the measurement of their contact differences of potential with respect to a barium reference surface of known work function. The copper surfaces formed from successive fractions of distillate showed considerable variation in the work function values determined for the first eight films deposited. The last six films were the most reproducible. This variation in work function was thought to arise from gas contamination of the condensing films. The creep properties of several types of commercial copper were determined by Schwape, Smith, and Jackson (186) over the temperature range 200" to 572" F. It was found that cold work increases the creep strength of copper, but this is lost at temperatures where recrystallization occurs. The addition of silver to either tough pitch or oxygen-free copper raises the temperature a t which rapid recrystallization occurs. Although silver was effective in these two coppers, the addition of silver to oxygen-free copper had a markedly greater effect on the creep rate of oxygen-free copper as compared with tough pitch copper. Schoofs (134) published his observations on a particular type of cold working on grains of alpha brass by cold rolling. Liicke (101) showed by experiment with cold-worked copper wire that the progress of recovering from cold working could be followed by electrical resistivity measurements. Eshelby (48) discussed crystalline dislocations in copper as a cause of damping. The effect of preaaure and temperature on the electrical resistance of six copper alloys was determined by Ebert and Gielessen (49) at pressures up to 4000 atmospheres, with a few determinations as high as 5500 atmospheres, and a t temperatures of 20" to 35" C. The determination of the pressure and temperature coefficients indicated that these alloys should serve as electrical-resistant manometers up to 20,000 atmospheres. Witzig, Penney, and Cyphers (167)studied the effect of various factors on the heat transfer rate of evaporating Freon 12 in a horizontal copper tube evaporator. Progressive evaporation, temperature differences, and evaporation temperatures produced the widest variation in heat transfer rates. The dropwise condensation on a heat transfer surface of copper, chromium, and nickel coated with stearic acid was investigated by Fatica and Katz (60). Kaye, Keenan, and McAdams (8.8) observed low values of heat transfer and friction loss for air'flowing at supersonic velocity through a 0.5-inch diameter tube of brass or plastic. The total hemisphericitl emissivities of copper and aluminum were determined by Best (18)a t tempcratures from 100" to 400" C. Over this range, the emiwivity of copper remains practically constant. Fenn, Hibbard, and Lepper (61)calculated the elastic coefficients for single crystals of alpha brass from tension and torsion experiments. True stress-strain data obtained by French and Hibbard (66) for copper and copper alpha solid solution alloys indicate that the strain-hardening coefficient is a function of the yield strength. Approximately linear relationships were found between the yield strength and the atomic percentage of the solute element. The influence of temperature from -188" to +165" C. on the strew-strain characteristics of oxygenfree copper has been determined by McAdam (106). The tension tests were conducted on cylindrical specimens a t strain rates a little slower than those ordinarily used in tension tests. Kolsky (88) investigated the mechanical properties of materials at high rates of loading. Stresses of the order of 20 microseconds were applied; copper showed irrecoverable flow. Bennett and Davies (16) obtained data for commercial brass, copper, high brass, 56 copper-44 nickel alloy. and 50 copper-50
1972
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
gold alloy a t temperatures up to 600" C. when subjected to transverse vibration. Fixed free test bars about 2.5 cm. long were maintained in transverse vibration by the action of superposed, steady, and alternating magnetic fields. It is shown that the ratio of Young's modulus a t any two temperatures is approximately equal to the square of the ratio of the two corresponding natural frequencies of the bar in the fundamental mode and in zero magnetic field. The structure of single crystals of alpha brass after cutting and polishing was studied by hfaddin and Hibbard (106). The secondary recrystallization in copper was studied by Kronberg and Wilson (90). The origin of crystal twins in brass was studied by iMaddin, Mathewson, and Hibbard (107). The formation of annealing twins in copper and 70/30 brass was studied by Kibbard, Liu, and Reiter (7S),who found that, under similar conditions of rolling and annealing, more annealing twins were found in 70/30 brass than in copper. Wilcock and Jones (154) report that silver plating of brass separators in gas-turbine roller bearings prolongs bearing life and reduces metal transfer under poor lubricating conditions of high s p d , pressure, and temperature. Croft and Dunn (-36) in a patent describe a tin-free copper-base bearing metal of high wear resistance. An alloy containing 88% copper, 4% aluminum, 4% lead, and 4% ninc was compared with an alloy containing 88% copper, 4% tin, 4% lead, and 4% zinc. The depths of wear in 720 hours were 0.00025 and 0.0014 inch, respectively. The vapor pressure of zinc over six copper-zinc alloys containing from 5 to 30% zinc was determined by Herbenar, Siebert, and Duffendack (78) a t temperatures from 642" to 970' C. Gertsriken, Geller, and Trofimenko ( 6 s ) studied the effect of tin, lead, and nickel an the diffusion of zinc from alpha brass in vacuo st 600' to 850" C. I t was found that tin and lead greatly increased the diffusion of zinc from alpha brass whereas nickel had no effect. FABRICATION PROPERTI E S
Wilson and Palmer (156) have shown that an intergranular parting type failure occasionally observed in the commercial fabrication of 70/30 brass has a structural appearance which can be duplicated by holding tensile specimens a t a constant stress a t elevated temperatures. It was concluded that this tendency could be minimized by ( a ) reducing internal stress left by cold working, ( b ) keeping the grain size down, ( c ) providing For uniform heating, ( d ) heating slowly enough to permit some stress relief before cracking temperatures are reached, and (e) placing work in the annealing furnace in such a fashion that surfaces known to be internally stressed in tension reach the temperature first. A description of condenser tube manufacture at the Allen Everitt Works of Imperial Chemical Industries Ltd. (10) also discusses the stress relieving of brass tubing. This is generally achieved by heating for 2 or 3 hours at 250" C. No appreciable change in hardness occurs at this temperature. A method of coloring copper black is disclosed in a patent by Rogers (124). The copper surface to be blackened is immersed in a boiling 1 to 10% sodium hydroside solution containing sodium hypochloride and phosphates. Newell (112) describes another solution for blackening copper and copper alloys; it consists of a 2% aqueous solution of a sodium derivative of mchlorobenzenesulfonamide and 2% sodium hydroxide. Spruance and Thirsk (140) have patented a procedure for producing chromate-arsenate coatings on copper, brass, and other materials. A detailed comparison of nickel and chromium plating thickness on copper alloys has been prepared, based on data from specifications of various services, societies, and industrial firm (8). An aqueous alkaline solution for depositing a brass coating by chemical displacement is described in a recent patent by Balden and Morse (19). Various uses of copper plated coatings ranging from 0 0005 to 0.001 inch in thickness were recently summarized (9). The uses are primarily for dip soldering, lubricant
Vol. 42, No. 10
in wire drawing, prevention of scuffing of steel gears, prevention of decarburization of steel during heat treatment, and stopoR to prevent carburizing of steel. Thin coatings of tin plate are also used as an aid in soldering brass. Leape (9s)has described an electrolytic wire cleaner for cleaning copper wire prior to enameling. A Swiss patcnt (S3)discloses a new procedure for cleaning copper and copper alloys. Vozdvizhenskii and Dmitriev (149) have determined the change of surface brightness with time in the course of anodic solution of copper and brass surfaces in phosphoric acid solution. Berger (16) has described a procedure for electrolytic polishing of alpha brass pressings suitable for use on a commercial scale. The electropolishing of 70/30 brass luggage parts ha9 been discussed by Axtell (11). The results of considerable experimental work on electropolishing have been published by Jacquet (80). Electrodeposited copper and electropolished brass or copper show a crystalline continuity whereas electroplated copper ou mechanically polished copper shows no crystalline continuity. Tricker (144) has discussed in detail the use of brass in the manufacture of clocks and instruments. Leaded brass strip for blanking and pressing is described with special regard to freedom from stresses in such parts as plates and wheels. The brazing of steel by phosphor-copper has been studied by Erdmann (48). This study reveals that the diffusion of phosphorus takes place through the grains and seems to have no effect on the grain boundaries. The phosphorus diffuses from the molten phosphor-copper into the steel with the formation of a hard, intermediate layer of Fe3P. A second diffusion zone of higher hardness is also found where the pearlite structure is unchanged. The phosphorus content of the brazing alloy should be kept about 1%higher than that ultimately desired in order to compensate for loss of phosphorus by volatilization. Damon ( S 7 ) discusses the effect of brazing temperaturea on base metals. He concluded that the effect is less than might be anticipated for such materials 8s copper, bronze, manganese bronze, red brass, silicon bronze, aluminum bronze, brass, phosphor bronze, tough pitch copper, Monel, various alloys of steel, and certain stainless steels. The use of gaseous fluxes for brazing steel has been studied by Edson, Paquette, and Newell (43). Such fluxes may prove useful for critical applications where conventional fluxes are not applicable; boron trifluoride is shown to be attractive. The wetting and flow of molten brazing alloys are, under these conditions, described as being excellent with the production of good quality brazed joints. Little or no attack of the steel surface occurs. A brazing paste is described by Wunsch (168); it consists of approximately 22.5 pounds of copper, as copper oxide, per gallon in suspension in either sodium petroleum base or in a base that does not change in viscosity with temperature. The copper brazing paste contains wetting and antispatter agents and a flux. A comprehensive report on the soldering of brass, copper, and tin plate and soldering fluxes has been prepared by Rodier. DeRosa et al. (12.8). The bibliography lists 194 articles and 247 American and British patents. An active noncorrosive type flux is described for bright and slightly oxidized copper, brass, and tin plate; this consists of an alcoholic solution of from 25% Teglac 128 resin, 1% ethylhexadecyldimethylammoniumbromide, 1.2% glycerol, and 10% amyl acetate. Rinkenbach and Clear (181) in a recent patent disclosed a soldering flux for lead-tin solders which consists of a mixture of rosin, stearic acid, petroleum jelly, and phenol. After soldering brass, copper, or zinc, the residues should be removed by wiping with ethanol or trichloroethylene in order to prevent corrosion. A flux which does not need to be removed consists of different proportions of rosin, stearic acid, and petroleum jelly. Stanton (141) has described a new selfsoldering tape consisting of a ribbon of vinyl plastic, in which aluminum-type heating fuels are dispersed, attached to a ribbon of lead-tin solder. When ignited the vinyl ribbon provides 5 safe and efficient heating medium for melting the solder sufficiently
Ootober 1950
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
that it can flow directly into the joint. The soldering of spliced copper wires by this method is described. Kelley (86) describes the fusion welding of copper in thickiiesses up to a/a inch by the inert gas shielded arc process. The welding of copper by the carbon arc process is described in detail by Child (39). The principles, joint preparations, design points, and practical examples of the use of this process in the electrical industry are given. Banash (14) discusses the fundamentals of the oxyacetylene welding and cutting process and calls attention to the ease with which practically all nonferrous metals and alloys can be welded by the oxyacetylene process. However, because of the differences in various types of copper, it is desirable to use deoxidized copper wherever possible in order to avoid m y difficulty due to weakening of the weld by the presence of cuprous oxide; a welding rod of deoxidized copper should also be used. JO
CORROSION RESISTANCE
The mechanism of corrosion of copper has received further study and discussion by Szabo (149). The corrosion of copper takes place primarily through the reduction of cupric ion by copper. This step of the reaction is accelerated when chloride ion, which leads to the formation of complex ions, is present. The rate determining step in this reaction occurs between cuprous ions with hydrogen ions and dissolved oxygen. The relative catalytic activities of various crystal faces of copper were determined by Leidheiser and Meelheim (94). Electrolytically polished monocrystalline spheres of copper were immersed in hot potassium formate solution of cobalt salts, and cobalt was catalytically deposited on the surface. The relative catalytic activities of the crystal faces of copper in order of decreasing activity were 210. 310, 321, and 320; 311 and 211; 100; 331 and 221; 110; and 111. The results were correlated with the spacing between c o p per atoms and the spacing between oxygen atoms in the formate molecules. The copper faces which did not have a 2.55 A. copper spacing parallel to the surface were the most active; those with the greatest number of 2.55 A. copper-copper spacings were the least active. Data presented by Graf (66) for copper-gold and silver-gold alloys shows that the mechanism of crack formation under strew depends principally on the nature of the corrosive medium. Intercrystalline cracking occurred in both strongly and weakly oxidizing solutions and transcrystalline cracking occurred in strongly oxidizing solution and with cubic and close-packed hexagonal structures. The solutions used in this investigation were ferric chloride, ferric sulfate, cupric sulfate, sodium sulfide, nitric acid, permanganic acid, chromic acid, and aqua regia. Waasermasn's (161) results of strewcorrosion tests in various corrosive media on brasses, certain steels, aluminum, and magnesium base alloys show that a straight-line relationship is obtained when the streea is plotted against life in hours on a log-log scale. A similar relationship was obtained when temperature (from 20" to 100" C.) was substituted for stress. White and Blazey (169)have reported several instances of season cracking of deoxidized arsenical copper tubing. .4ccording to Elder (44), corrosion in water or water-alcohol solution in contact with one or more of such metals as iron, brass, copper, aluminum, and solder is prevented by the simultaneous addition of seved inhibitors such as 0.2 to 1.0% sodium chromate, 0.25% benzoic acid, 0.25% sodium benzoate, or 0.5 to 1.0% hexamethylenetetramine with sufficient alkali added to the solution to adjust the p H from 7.5 to 10.0. Corrosion in polymetallic systems of all the specified metals is said to be prevented even after heating for 1 year at 65" C. Another inhibitor (44) may be used instead of the hexamethylenetetramine-namely, L25% amin* 2-methyl-1-propanol with the pH adjusted to 10.0. Hochberg and King (74)published the results of a survey on the action of over 60 quinonas and dyes as corroding agents in acid solution on oopper, cadmium, tin, and lead. Reactions are described whose rates are ( a ) diffusion controlled, ( b ) chemically controlled, ( e )
1973
partly diffusion and partly chemically controlled, and ( d ) subject to inhibition by reduction products or intermediate compounds. Some metal-salt concentration cells were studied by Piontelli and Simonetta (116). The potentials of copper sulfide, nickel sulfide, and a mixture of copper and nickel sulfide in sulfuric acid solution and copper sulfate solution, using a hydrogen reference electrode were determined by Ustinskii and Chizhikov (146). The anodic behavior of copper in hydrochloric acid solution has been studied by Bonhoeffer and Gerischer (21). It was found that a t certain current densities, a surface film forms on the copper anode and dissolves periodically. The reduction of oxygen on nine different metals was studied by Delahay (39). It is concluded that anodic oxidation of cop er can only occur a t potentials more positive than those obtainelfrom E = 0.47 0.059 pH. Using thermodynamic data reported by Latimer and the method developed b Pourbaix for the reaction, X u HzO= CUZO4- 2" 2er Azdvizhenskii (160) measured the static and dynamc potentials of various copper surfaces in phosphoric acid solution (density 1.50). Two t es of surfaces were studied one had a texture produced by chisegg or rolling and the other a disoriented texture obtained by annealing for 6 hours in vacuo ai 950" C. The chiseled or rolled surface not subjected to anodic solution showed static otentials more negative than the surfacf of annealed copper. T i e potential however, shifted after anodic treatment to become positive by about 10 mv. The chiseled OJ rolled surface showed unusually high anodic polarization which increased with the degree of perfection of the texture. For example, about 50 mv. were obtained for the rolled surface and 100 mv. or more for the chiseled surface. The dynamic anodic potentials of different crystal faces were found to differ considerablj more than the static potentials. The local cell action between copper and copper oxlde film was studied by Tijdt (143). The local electrolytic effect on metal surfaces due to either the presence of a nobler metal or an oxide film was determined and measured on the basis of the increased rate of corrosion with aeration. It was also measured directly by determining the potentials between the aerated metal surface and a less noble electrode. The rate of oxidation of copper and the resulting film thicknesses were also determined. The rate of corrosion of co er in glacial acetic acid wae measured by Bosworth (23). $ie corrosion rate of electricaily heated copper wires in this medium was determined as a function of temperature. Whitney (163) re ards 10 to 15% alum solution, such as is used in the paper injustry, as being too acid and corrosive to be satisfactorily handled by copper and brass. Splittgerber (139) studied the action of ammonia in steam and steam condensates on copper alloys. He concluded that in the absence of oxygen the copper alloys are dissolvod by ammonia when the concentration of ammonia is more than 10 mg. per liter In the presence of oxygen, le@ than 1 m of ammonia per liter was found to have a dissolvin effect. appears to be substantially in agreement with o&er data which indicate that 1 or 2 mg. of ammonia per liter have a negligible effect on admiralty and copper condenser tubes, whereas 5 to 25 mg, of ammonia per liter have led t o objectionable rates of corrosion in gas-bound areas of condensers. The catalytic decom osition of ammonia on copper and platinum surfaces was studied by &hay (129) A mechanism was proposed which seems to be satisfactory both from the kinetic and energy point of view. This mechanism postulates that the ammonia occupies two adjacent places when absorbed; hence its molecules become anchored by two of i h hydrogen atoms and the remaining NH radical points away from the surface. The decomposition is the reaction of two such neighboring radicals forming molecules of nitro en and hydrogen and leaving four absorbed hydrogen atoms on t8e surface.
-
+
+
Riches (190)in a recent patent discloses a method of reactivating copper contact masses which have become contaminated with a coating of metal chlorides, when used in the purification of titanium chloride. The copper oatalyst is reactivated by soaking in a concentrated solution of sodium chloride in the absence of appreciable amounts of oxygen. Experiments by Levin and Pomosov (98) m t h powdered copper indicate that there is relatively little corrosion in moist air or dry carbon dioxide, sulfur dioxide, or ammonia. Rapid corrosion occurs, however, when the latter gases are moist. With dry hydrogen chloride gas the corrosion is greater than that obtained with moist hydrogen chloride. Sanderson reports (197)that copper bond wires and tag wirer in direct contact with lead cable sheaths have caused corrosion
1974
I N D'U S T R I A L A N D E N 0 I N E E R I N G C H E M l S T R Y
and local failure of the cable. I t is recommended that the bond wires be tinned, bent a t right angles, and attached to the sheath by wiping metal. The tag wire should be kept away from the lead sheath by installing over tape wrapping. Bonwitt (,??8)has described the results of extensive tests on electroplated and metallic-coated copper members bolted to aluminum. Various compounds were also tested between noncoated contact surfaces. Several methods were found to be effective in preventing contact corrosion. Shearon, Hall, and Stevens (137) indicate that copper piping has been satisfactorily used to convey chlorine from vaporiscr to chlorinator. Williams (166),in a description of the new General Mills plant in Kankakee, Ill., refers to the use of copper in the construction of the continuous evaporators for heat transfer. The fatty materials handled in the equipment are not corrosive to copper. Kenyon, Stingley, and Young (86) indicate that shortly after World War I, Armour had six cast-iron stills with copper condensers and receivcrs in operation for the distillation of fatty acids. Paul (116) states that a still, introduced to this country from Germany in the early 1930's and still in use, consisted of a large number of direct-fired vacuuin pans, cast in aluminum bronze with large wrought copper vapor pipes and Condensers with aluminum t u b a A steam-heated preheater had a bronze tube sheet, copper shell, and cupronickel tubes. The life of the large casting has been excellent. Friend and Mason (57) have published considerable information obtained from corrosion tests in the processing of soap and fatty acids. One plant corrosion test in the distillation of fatty acid in a vacuum batch still showed that copper in both the vapors and liquids corroded a t 0.0040 and 0.0046 inch per year. Copper in a continuous fatty acid vacuum bubble tower corroded a t r a t a between 0.0027 and 0.0058 inch per year depending on the location within the tower. It is shown that air agitation during sulfuric acid wmhing of fats and fatty acids increased the corrosion rate of copper from 0.0010 to 0.0040 inch per year to 0.035 inch per year; the lower values were obtained when steam agitation was used. A t both the liquid level and below the liquid level in storage of crude mixed fatty acids, copper corroded a t a rate of O.OO& inch per year. Copper in a high vacuum fractionating column during distillation of light-odor fractions of refined tall oil corroded a t a rate of only 0.0030 inch per year. Another set of data, however, ahowed that refined tall oil was quite corrosive since a 0.032inch thick copper specimen was completely corroded in 195 days. The corrosion resistance of copper and several other materials toward fatty acids dissolved in carbon tetrachloride, chloroform, and methanol was determined by Dubriaay (41). Lewis ( 9 9 ) hss studied the corrosion resistance of tinned and tin alloy foils, copper foils, and solder in contact with dairy products. According to Velfort (148) hard and soft copper tubing is giving satisfactory performance in use for main and services on both manufactured gas and natural gas and mixtures of the two. Considerable expense can often be avoided by drawing this tubing through unserviceable mains. Porter (117) reports that c o p per is not corroded by fluorine gas at moderate temperatures. Seigel, Bryan, snd Huppert (136) have presented data on the boiling of Freon 12inside smooth horizontal copper tubes. Their data are presented in graphical form with regard to heat transfer. Considerable information has been published by Schlapfer and Bukowiecki (139,133) regarding the corrosion resistance of copper and other materials toward motor fuels, such as hydrocarbons, alcohols, aldehydes, ketones, and esters. These materials were teated individually and in mixtures. In each case, the effect of traces of water was determined. In general, it was found that water-free fuels have only a weakly corrosive action even though acidified. The corrosiveness of exhaust gases produced by commercial motor fuels has received further study by Schikorr (1S1). It was found that they attack cast iron moderately and copper strongly a t a temperature of 400' C. At lower
Vol. 42, No. 10
temperatures, the copper continues to corrode somewhat and it is believed that the increaud resistance is probably due to the deposition of oil and soot on the copper surface. A container for the storage y d transport of liquid hydrogen and liquid helium has been announced by Hoffman Laboratories Inc. (76). This container is made of three concentric copper spheres. The inner and outer spheres form a conventional vacuum flask with facing interior surfaces polishd to a mirrorlike finish. Between these a third sphere, highly polished on both sides, acts as a radiation shield. This shield is attached by a connection to the inner sphere of a smaller side flask for containing liquid nitrogen. The main flask is fitted with an outer protective casing made o f aluminum. Cook and Dickinson (34)found that most insecticidal solutions were resisted in a satisfactory manner by copper and brass. Insecticides in kerosene or a fuel-oil base are not corrosive, showing rates of corrosion for copper of 1.2 and 0.75 mg. per square dm. per day; 2-4-D in water inhibited corrosion of copper since H corrosion rate of only 0.34 mg. per square dm. per day OCCUITH~ Similar results were obtined for DDT in water, where copper and b r a corroded a t 1.6 and 2.0 mg. per square dm. per day, respectively. DDT in soft water, however, was quite corrosive since copper suffered from corrosion pitting a t a rate of 0.051 inch per year. Two other corrosive insecticide solutions were reported-ziamely, chlorodan in water and sodium arsenite in water. The former solution corroded copper and brass a t rates of 12.0 and 13 mg. pcr square din. per day. The latter solution corroded this material a t ratesof 5.2 and 3.7 mg. per square dm. per day. It has been found by Gindin and Pavolova (64)that 0.0278 gram of iodine per ml. of benzene corroded copper at a rate of 240 mg. per square dm. per day and 0.014 normal iodine in isooctane corroded copper a t approximately the same rate. Mtiller and Reuther (110) concluded from photomicrograph$ and potential measurements that little amalgamation takes place when copper is dipped into dilute solutions of mercurous ions (of the order of saturated mercurous sulfate). The potential of copper utrip so treated and then placed in aqueous copper sulfate bolution is the same as that obtained for pure copper. The oxidation of copper under various conditions has CODtinued to receive further study during the past year. Frisby (68) found that electrolysis of 0.1 N soda solution with co er electrodes resulted in a nonadherent cupric oxide film. &us oxide is monoclinic, whereas the oxide which forms on copper on heating in air at temperatures below 175' C. results in the formation of strongly adhering cuprous oxide. The latter oxide and copper are face centered cubic and the orientation of the copper surface atoms is maintained when cuprous oxide in formed but not when cupric oxide is formed. The oxidation and reduction of thin films of copper oxide were studied by Garner, Gray, and Stone (61) who studied the kinetics of the reaction on the basis of heats of absorption determined for oxygen, carbon monoxide, hydrogen, and carbon dioxide (66). Czerski (36) found that the cu rous oxide obtained from copper and oxyqen at 950' C. containe80.07 to 0.35% copper in excess of ttie stomhiometric amounts. It is suggested that the excess of the copper is the result of a reaction a t the cu ric oxide/cuprous oxide surface, that the cuprous oxide is oxidizezby oxygen diffusing through the cupric oxide layer, and that then it is reduced by copper atoms. Cabrera ($8)has discussed Mott's theory for the oxidation of metal which is extended to oxides such as cuprous oxide for which the metal diffuses through the oxide b the mechanism of vacant lattice points. The logarithmic law stould be valid to low temeratures and for oxygen pressures above lo-' mm. Shirai 138) studied the oxidation of a thin single crystal film of copper. Elliott (46) has described and illustrated a furnace for heating metallic copper in a current of gas from which traces of oxygen are to be removed. The tube is packed with copper oxide wire fragments held in lace with rolls of copper gauze. The copper oxide is reduced y! hydrogen which is mixed with a carrier stream of nitrogen or other inert gas which is passed through the hot tube.
P
According to Keim (84),the principal cause of premature wear of phosphor bronze Fourdrinier wire appears to be mechanica abrasion with corrosion usually playing only a subordinate part
Ootober lQS0
INDUSTRIAL AND ENGINEERING CHEMISTRY
Corrosion, however, occurs in slow running machines in which the wire is in constant contact with dilute acids. Beater additives, such aa d u m hydrogen sulfite for brightening unbleached pulps, may be detrimental to the wire; alum, high in acid, is also objectionable. Occasional washing with dilute hydrochloric acid solutions is not considered troublesome. Sawyer, Beals, and Neubauer (188) described in table form the various uses of brass in Fourdrinier papermaking machines. Carpenter (30)recommends various types of strip welding for attaching corrosion-resistant liners to petroleum refinery veaaels. Ellison (47) reports that dezincification and season cracking are uncommon in good quality brass tubes used in petroleum refinery heat exchangers. Impingement corrosion encountered when sea water is ueed for cooling purposes is prevented by using aluminum brass and 70/30 copper nickel alloy. Van Der Baan (147) reporta that aluminum brass of good quality is a versatile and economical condenser tube material for the conditions prevailing a t the refinery at Curacao. The temperature of the incoming vapors ranges from 80' to 330' C. A11 the tubes at this refinery are of inhibited aluminum brass, which has proved itself through a number of years to be the most economical choice for local conditions and superior to admiralty, cupronickel or aluminum bronze. An examination of 135 admiralty brass tube service failures by Lynes (102) showed that plain admiralty usually failed from dezincification whereas inhibited admiralty failed from deaincification only under unusual circumstances. Transgranular cracking due to corrosion fatigue was found to be an important cause of tube failure in oil refineries. Oden and Burch (113) in discwing the alkylation of isobutane with propylene using sulfuric acid as the catalyst reported that no more than the usual amount of trouble has been experienced with the condensers and coolers which have admiralty tubes. Condenser tube bundles of admiralty metal handling the overhead stream in a thermal polymeriaation plant were found by Camp and Phillips (89)to suffer from severe corrosion when one of the charge streams became contaminated with a small amount of methyl chloride. No difficulty due to corrosion has been experienced in condenser tube bundles of admiralty metal handling the overhead stream COW taining triethanolamine. The hot processing of nonacid cheInicals from hydrocarbon synthesis is described by Eliot, Goddin, and Pace (46) aa being carried out in copper and copper-alloy equipment to maintain satisfactory product, purity, and color. It was recommended that special precautions must be taken to prevent oxidation of aldehydes and resultant formation of corrosive acids. Hepp, S p e m d , and Itandall ( 7 1 ) have described the results obtained from a pyrolysis coil made of copper-lined 18-8 stainless steel duplex tubing. The pyrolysis of ethane at 1700' to 1900O F. led to no plugging of the copper-lined stainless steel, duplex tube. It is believed that catalytic effects were absent on the copper surface. Similar runs, however, in an unlined 18-8 stainless Bteel tube were shut down in a few minutes because of coke deposition in the coils. Furth (69)discussed the use of admiralty, 70/30 cupronickel, condenser tubing and bimetallic tube s h e t a as a means of preventing corrosion failure in refinery heat exchanger equipment. Hoover (77) in a recent patent discloses that cuprous naphthenate is used to stabilize sulfur compounds in crude petroleum so that on distillation they do not form mercaptans or disulfides. Kats (81) reports that the corrosion of copper in aqueous solutions of potassium chloride, sodium chloride, hydrochloric acid, magnesium sulfate, and magnesium chloride depends on the buffering of the solution. In a buffered alkaline solution copper corrodes a t a constant rate and forms a solid corrosion product. Under these conditions, the rate of corrosion is approximately 5.4 mg. per square dm. per day. In unbuffered acid solutions the rate of corrosion of copper increases with time. The rate of corrosion reported ranged from 7.7 to 508 mg. per square dm. per day. It was sugge-sted that any measures interfering with the dworption of cuprous ions will slow the corrosion of copper. For
1975
example, hydrogen sulfide gives some protection but, unfortunately, not against pitting. The addition of alkaline buffers, such as lime or magnesium hydroxide, to salt solutions in copper containers was proposed to reduce corrosion. Sodium hypochlorites are reported by Botham and Dummett (84) (whether containing potassium permanganate or not), to be corrosive a t 150 parts per million of available chlorine at 40' C. to such materials aa tinned copper, nickel silver, wrought stainless steel, cast stainless steel, and aluminum. It waa found that the corrosion could be inhibited to a considerable degree by the addition of sodium silicates. The oorrosivonese of the hypochlorite is also discussed by Lesser (07). Naiaiinen and Tarnminen (111) found that cupric oxide is the solid phase present in equilibrium in weak solutions of sodium perchlorate. The solubility product for cupric oxide is 2.2 X 10-20. The cupric hexahydroxyperchlorate is stable in solutions of sodium perchlorate a t a concentration greater than 0.1 M. Gregory and Newing (B8)have discussed the lubrication of c o p per, silver, and steel by silicones. Denison and Romanoff (40) have published data of considerable interest and usefulness regarding the corrosion resistance of copper, lead, and zinc and certain rtlloys of these metals after exposure to different soil conditions for a maximum of 14 years. Some of the conclusions reached are: With respect to weight losses tough pitch copper was generally more resistant than deoxided copper and the copper-silicon alloys, except in soils high in sulfides. However, in a number of the soils, the maximum deptha of pita on tough pitch copper were greater than those on one or more of these materials. The loss in weight of the copper-zinc and copper-nickel-zinc alloys was approximately in the order of increasing zinc content, except in soils high in sulfides in which the reverse order was followed. Admiralty metal showed the greatest tendency toward localized corrosion of any of the cop er-zinc alloys. Although a two-phase leadel silicon brass showed the least tendency to develop deep pita, this alloy was dezincified in many of the soils. All two-phase copper-zinc alloys were dezincified to some extent in most of the soils, except a 00-40 brass containing 0.08% arsenic which showed only superficial discoloration. The presence of arsenic did, however induce intergranular corrosion in the specimens exposed to cinders. In general, copper, zinc, and lead, and alloys of these metals, were corroded more severely in poorly aerated soils, particularly in soils that were highly acid or that contained high concentrations of soluble salts. Copper was corroded in soils high in sulfides.
A layer of lead alloy between copper wire and the rubber insulations in cables has been found (7) to be beneficial in preventing corrosion in sulfurous atmosphere and from sulfuric acid formed from sulfur in vulcanized rubber. Gindin and Sils (86) found that the corrosion of copper by sulfur in a solution of benzene could be inhibited by the addition of 9,lO-anthraquinone. Data presented by Hamilton and Woods (70) illustrate the well-known fact that free sulfur and sulfur bonded only to other sulfur atoms, such aa the third and fourth sulfur atoms in tri- and tetrasulfides, are removed completely by reaction with copper metal at 100" C. The sulfurized terpene hydrocarbons seem to be slightly more reactive than dibenzyl disulfide. The reaction increases considerably above 150' C. between sulfurized terpene, hydrocarbon, and copper. Oknin (114) calls attention to the corrosion resistance of copper, silver, and mercury in dilute sulfuric acid. These metals are cohverted to the sulfates with the evolution of sulfur dioxide when immersed in concentrated sulfuric acid at temperatures above 150' C. The order of the potentials of copper and other metals in solutions of their bromides in dry toluene containing aluminum bromide waa determined by Galinker (60). The order of the potentials waa found to be aluminum, copper, silver, bismuth, antimony, and arsenic. Roe (193) briefly discussed the satisfactory corrosion resistance
1976
INDUSTRIAL AND ENGINEERING CHEMISTRY
of silicon bronze, brass, and other materials in the form of bolts and washers for anchoring under drain plates in the porous plate tilter underdrain system used in water works. Decker, Wagner, and Marsh (38)found, in a series of corrosion-erosion tests conducted in boiler feed water t o select materials for the construction of pumps and regulating valves, that navy bronze appeared satisfactory at temperatures up t o 320” F. A leaded bronze was found unsatisfactory a t all test temperatures. The fouling of marine-type heat exchangers was discussed in considerable detail by Bethon (19) with specific reference t o heat exchangers installed aboard naval vessels such as lubricating and jacket water coolers, steam condensers, fuel-oil heaters, and distilling plants. The good corrosion resistance of f 0 / 3 0 cupronickel toward sea water is repeatedly stressed on the basis of experience. Freeman and Tracy (6.4)have described the results of corrosion tests conducted in an experimental condenser at a sea water velocity of 11.7 feet per second. These tests showed that the copper-nickel alloys containing iron were markedly superior t o most of the standard condenser tube alloys, such KS admiralty, under the test conditions (clean sea water). The effect of 0.75% iron in an alloy containing ‘30% copper, 10% nickel, was particularly good; this alloy wa\ ruperior to an alloy containing 92% copper and 8% tin. Fontana and Luce (63)ib a series of erosion-corrosion tests of metals and alloys showed that the corrosion rcsistance of an alloy containing 70% copper and 30% nickel and 0.12% iron was increased threefold when the iron content was increased up to 0.59%. Tests described by Mills (108) extending over a period of 21.5 nionths in a turbine oil cooler showed that an alloy containing 89% copper, 10% nickel, and O.8yOiron had marked resistance to corrosion hy sea water w drawn from the Corpus Christi ship channel. Lynes (103) has also discussed the beneficial effect of the presence of iron in the copper-nickel alloys with regard to corrosion resistance toward sea water. Rogers (185) has proposed a method of assessing the relative corrosiveness of different sea waters. Experiepce accumulated over a period of many years shows that the corrosive attack of sea waters on the copper-base alloys differs considerably because of various factors inherent in the sea waters t,hat are not easily revealed by ordinary chemical tests. These factors vary with the seasons and with the time during which samples are stored before testing. The proposed simple test is known as the copper-corrosion index; it consists basically of determining the amount of copper dissolved in 22 hours under standard test conditions. LITERATURE CITED
(1) American Wheelabrator & Equipment Corp., Chen. Eng. News, 27, No. 43, 3150 (1949). (2) Anderson, E. A,, and Jillson, D. C. (to N. J. Zinc Co.), U. S. Patent 2,479,595 (Aug. 23, 1949). (3) Ibid., 2,479,596. (4) Anderson, P. A., Phys. Rev., 76, 388-90 (1949). (5) Anon., Chem. Eng. News, 28, No. 23, 1950 (1950). (6) Anon.. Copper Development Assoc., Pub. 43, 88 (1945). i7) Anon., Lead, 17, No.-2, 6-7 (1947). I Anon.. Metal Finishing, 47, No. 10, 85 (1919). Ibid., 47, No. 12, 74 (1949). Anon., Metal Ind., 75, No. 8, 143-7 (1949). Axtell, W. G., Ibid., 75, No. 5, 88 (1949). Baker, W. A., and Hallowes, A. P. C., J. Inst. Metals, 75, 74158 (1949). Balden, A. R., and Morse, L. M. (to Chrysler Corp.), U. S. Patent 2,496,845 (1949). Banash, J. I., Intern. Acetylene Assoc., 189-98 (1944, 1945, 1946, 1947). Bennett, G. E., and Davies, R. &I., J . Inst. Metals, 75, 759-76 (1949). Berger, P., PTOC. Intern. Electrodeposition Conf., 3, 33-40 (1947). Berwick, J. D. (to Olin Industries Inc.), U. S. Patent 2,494,736 (Jan. 17, 1950). Best, G., J . Optical SOC.Am., 39, 1009-11 (1949). Bethon, H. E., Trans. Am. Soc. Mech. Engrs., 71, 855-69 (October 1949). Bloenbergen, N., Physico. 15, 588--92 (1949)
Vol. 42, No. 10
(21) Ronhoeffer,K. F., and Geriacher, J., 2.Elektrochem., 52, 149-60 (1948). (22) Bonwitt, W. F., Elac. E w . , 67, 1190 (December 1950). (23) Bosworth, R. C. L., J . Proc. Roy. SOC.(N.S. Wales),81, 206-.9 (1947). (24) Botham, G. H., and Dummett, G. A., J. Dairy Research, 16, 23-38 (1949). (25) Bouchez, T., and Kayas, G . , J . Phys. Radium, 10, 110-19 (1949). (26) Bridgeport Brass Co., “Duplex Tubing,” Tech. Bull. (1950). (27) Bridgeport Brass Co., “Technical Handbook,” (revised 1950). (28) Cabrera, N., Phil. Mag., 40, 175-88 (1949). (29) Camp, E. Q., and Phillips, C., Corrosion, 6, No. 2, 39 44 (1950). (30) Carpenter, G. C., Petroleum Proc., 5, 21-5 (1949). (31) Chace, P. G. (to Metals & Controls Corp.), U. S. Patent 2,482.897-900 (Sept. 27,1949). (32) Child, I. H., Welding, 17, 455-7 (October 1949). (33) Ciba, Ltd., Swiss Patent 252,362 (Oct. 16, 1948). (34) Cook, G. S., and Dickinaon, N.,Corrosion, 6 , No. 5, 137.-9 (1950). (35) Croft, H. P., and Dunn, E. J. (to Chase Brass & Copper Co.), 7T. S. Patent 2,492,786 (Dec. 27, 1949). (36) Czerski, L., Roczniki Chem., 23, 19-28 (1949). (37) Damon, S., Iron Age, 164, No. 8, 67-70, 114 (1949). (38) Decker, J. M., Wagner, H. A., and Marsh, J. C., Trans. .4m SOC.Mech. Enps., 72, 19-26 (1950). (39) Delahay, P., J . Electrochem. Soc., 97, No. 6, 198-212 (1950). (40) Denison, I. A., :and Romanoff, M., J . Research Natl. Bur. Standards, 44, 259-89 (1950). (41) Dubrisay, R., Metauz &. Corrosion, 23, 278-84 (December 1948). (42) Ebert, H., and Gielessen J., Ann. Physik, (G), 1, 229-40 (1943). (43) Edson, A. P., Paquette, D. G., and Newell, I. L., J . Metals, 1 S o . 9, 25-7 (1949). (41) Elder, J. A., Jr. (to hferck & Co. Inc.), U.S. Patents 2,478,755 6 (Aug. 9, 1919). (45) Eliot, T.Q., Goddin, C. S.,Jr., and Pace, B. S.,Chem. Eng Progress, 45, No. 8, 532-6 (1949). (46) Elliott, K. A. C., Can. J. Research, 27F, 299-300 (1949). (47) Ellison, A. G., Brif. Petroleum Equip. News, 1, No. I . 27 (1948). (48) Erdmann, F., Metall, 3, 186-7 (1949). (49) Eshelby, J. D., Proc. Roy. Soe. (London), A197, 396-416 (1949). (50) Fatica, N., and Katz, D. L., Chem. Eng. Progress, 45, No. 11. 661-74 (1949). (51) Fenn, R. W., Jr., Hibbard, W. R., Jr., and Lepper, H. A., J . MetLLls, 188, NO. 1, 175-81 (1959). (52) Flus~fisoh,M., Swiss Patent 257,785 (April 1, 1949). (53) Fontana, M. G., and Luce, W. A., Corrosion, 5, No. 6, 189-93 (1949). (54) Freeman, J. R., Jr.,andTracy, A. W., Ibid.,5, No.8.225-8 (1949). (55) French, R. S., and Hibbard, W. R., Jr., J. Metals, 188, No. 1. 53-8 (1950). (56) Fricke, R., Naturuiasenschaften, 34, 313-14 (1947). (57) Friend, W. Z., and Mason, J. F., Jr.. Corrosion,5, No. 11, 35.5 68 (1949). (58) Frisby, H., Compt. rend., 228, 1291-2 (1949). (59) Furth, M. A,, Proc. A m . Petroleum Inst.. 28M, 111. 26 3 4 (1948). (60) Gaiinker, V. S., Zhur. Obshchei Khim., 19, 2048-50 (1949). (61) Garner, W. E., Gray, T. J., and Stone, F. S., Bull. a m . chin France, 1949, pp. D 177-182. (62) Garner, W. E., Gray, T. J., and Stone, F. S., Proc. Rou. Soc (London), A197,294-314 (1949). (63) Gertsriken, S. Do,Geller, A., and Trofimenko, V., Neotg. Khiiri Akad. Nauk. U.S.S.R., 16, No. 2, 174-9 (1946). (64) Gindin, L. G., and Pavolova, M. V., Doklady Akad, Nauk S.S.S.R., 69,377-80 (1949). (65) Gindin, L. G., and Sils, R. Kh., Ibid., 63, 685-8 (1945). (66) Graf, L,,Metollkunde, 40, 275-80 (1949). (67) Grange, H, L. (to General Motors Corp.), U. S. Patent 2,489. 529 (Nov. 29, 1949). (68) Gregory, J. N., and Newing, M. J., Australian J. Sci. Research S ~ TA, . 1, 85-7 (1948). (69) Grodsky, V. -4., Metal I d . , 74, No. 21, 429 (1949). (70) Hamilton, L. A., and Woods, W. W., IND.ENG.CHFUM., 42, 513-19 (1950). (71) Hepp, H. J., Spessard, F. P., and Randall, J. H., Ibid., 41 2531-35 (1949). (72) Herbenar, A. W., Siebert, C. A., and Duffendack, 0. S., J Metah, 2, No. 2, 323-6 (1950). (73) Hibbard, W. R., Jr., Liu, Y.C., and Reiter, 9.F.. Ibid., 1, So. B 635-6 (1949).
