INDUSTRIAL AND ENGINEERING CHEMISTRY
October 1948
obtained from the several suppliers. The material has found many applications, as panels, shields, supports, spacers, and numerous insulating parts. Properties of some commercial glass-bonded mica products are given in Table 111.
1785
certain applications where a white, hard body is desired. Typical properties of the latter ceramic are given in Table IV. Except for the large shapes. equipment may be made of either ceramic. LITERATURE CITED
Berberich, L. J., and Bell, M . E., J. Applied Phys., 11, 681-92
CHEMICAL STONEWARE
(1940).
The production of chemical stoneware and its applications have been reviewed in several publications (8, 12, 18). This ceramic is a vitrified product which more generally has been prepared from mixtures of the following range of composition: 30 to 70y0clay, 5 to 25% feldspar, and 30 t o 60% silica. Special compositions have been employed for certain applicationse.g., where greater thermal endurance is needed or for certain specific operations (4, 5, 9). Work has been under way to enhance the thermal endurance of chemical stoneware (8,15). Physical properties of typical chemical stoneware and chemical porcelain are given in Table IV.
Ewell, R.€I.,Bunting, E. N., and Geller, R. F., Natl. Bur. Standards Research, 15,551 (1935); R.P. 848. Geller, R. F., Yavorsky, P. J., Steierman, B. L., and Creamer, A. S.,Natl. Bur. Standards, R. P. 1703 (1946). General Ceramics and Steatite Corp., “Properties of Ceramic Bodies for Chemical Stoneware Equipment.” Heratein, F. E., Chem. Eng., 53, 214-16 (1946); 54, 216-20 (1947).
Howatt, G., Ihid., 29,117-23 (1946). Joint Army-Navy Specification, JAN. 1-10,April 29, 1944. Kingsbury, P.C., Trans. Am. Inst. Chem. Engrs., 36,N o . 3,43342 (1940).
Kingsbury, P. C., Trans. Electrochem. SOC.,75,131-9(1939). Mycalex Corp. of America, data from, 1948. Navias, L.,J. Am. Ceram. SOC.,24,145-55 (1941). Olive, T. R., Chem. & Met., 40, 369-71 (1933); 46, 512-16 (1939).
TABLEIV. PHYSICAL PROPERTIES OF TYPICAL CHEMICAL STONEWARE AND CHEMICAL PORCELAIN S ecifio gravity FPexural strength lb./sq. in.
.
Tensile strength, ’lb./sq. in. Compressive strength, lb./sq. in. Modulus of olasticity, lb./sq. in. X 10s Coeffioient of thermal expansion (20° to 600° C.) X 10-8
Chemical Stoneware
Chemical Porcelain
2.2 6,500 2,600 80,000
2.5 14,000 6,000 100,000 15
10 5
4
Stoneware, like glass, resists all acids except hydrofluoric. Strong, hot caustic alkalies have a slight surface action on this ware. This universal chemical resistance, with above-mentioned exceptions, explains its many uses in the chemical and process industries. I t s many applications include tanks and storage vessels in various shapes and with capacities ranging from 10 to 700 gallons, piping and cooling coils, towers, pumps, ducts, and fans. The materials and processes involved in the manufacture of these items provide for a relatively inexpensive ceramic. Chemical porcelain is preferred to chemical stoneware in
Rigterink, M. D., Bell Telephone System, Tech. Pub. B-1325 (1941).
Rigterink, M.D., Grisdale, R. O., and Morgan, 9. O., J. Am. Ceram. SOC., 25,439-43 (1942). Robitschek, J. H., Ceram. Ind., 41,48-51,64-6 (1943). Russell, R., Jr., Electronics, 17 (1944). Scholes, W. A.,data t o be published during 1949. Singer, F., Ceram. Age, 17,300-5 (1931). Smoke, E. J., Ceram. Age, 51 (3),115-16 (March 1948). Smoke, E. J.,paper presented before Whiteware Division, American Ceramic Society, 1948. Snyder, N. H., and Gebler, K. A., data to be published during 1949.
Thiess, L. E., J . Am. Cerum. Soc., 26,99-102 (1943). Thurnauer, H.,Ceram. Ind., 29,362 (1937). Thurnauer, H.,and Rodriguez, J . Am. Ceram. Soc., 25, 443-50 (1942).
Ueltz, H. F. G., Ibid., 27,33-9 (1944). Von Hippel, A., et al., IND. ENG.CHEM.,38, 1097-109 (1946). Wainer, E.,Ceram. Age, 11,201-4(1946). Wainer, E., Trans. Electrochem. Soc., 90,89(1946). Wisely, H.R.,and Gebler, K. A., paper presented before Whiteware Division, American Ceramic Society, 1945. RECEIVED July 14. 1948.
Wrought Copper and Copper-Base Alloys C. L. BULOW, Bridgeport Brass Company, Bridgeport Conn.
0
NE of the outstanding publications during the past year is
the American Society for Metals’ handbook, in which is summarized a wealth of information regarding the mechanical and fabrication properties and corrosion resistance of copper and copper alloys ( 2 ) . Information can be readily found under such headings as castings, production, hot working, cold working, annealing and heat treating, joining, machining, finishing, corrosion resistance, metallography, and factors determining application and properties of wrought and casting alloys. Stauffer, Fox, and DiPietro (44) have shown that improved physical properties can be obtained in copper through vacuum melting and casting. Kochendorfer (BY), in his study of the tensile strength of copper and aluminum, demonstrated that the tensile strength is a function of the velocity of stretching and the temperature. Jaffee and
Ramsey (86)have published considerable information regarding the effect of temperature on the mechanical properties of three representative aluminum bronzes between -295 O and 1000’. I?. The strength of the bronzes tested was highest a t subzero temperatures and dropped rapidly above 600” F. I n the discussion of this paper, some information also is found on the creep rate of several aluminum bronzes. Voce (51) concludes from his own work and published creep data on nonferrous metals and alloys that there are no copper-base alloys with properties superior to those shown by the aluminum bronzes which he investigated, and states that for such reasons and because of their great resistance to oxidation and scaling, the aluminum bronzes as a class appear to be the most promising of the copper-base alloys for service at moderately elevated temperatures. Nowiok and Machlin (35) derived an equation for the steady state creep of
1786
.
INDUSTRIAL AND ENGINEERING CHEMISTRY
pure polycrystalline metals through the dislocation theory and the theory of rate processes. This creep equation is in good agreement with the data found in the literature, and its use should, in time, reveal its sphere of usefulness. Seigle and Brick (42) have compiled considerable information regarding the low temperature mechanical properties of copper and other materials in a survey that clearly reveals that only face-centered cubic metals retain their ductility as the deformation temperature approaches zero. Kostenets (98) concluded from a comparison of various copper-base alloys with one another and with other nonferrous alloys, that their mechanical properties make phosphor bronze and beryllium bronze the most suitable for low temperature application. Palmatier ( S 7 ) , in discussing materials for the construction of refrigeration equipment for use at ultralow temperatures, stated that the “principal problem is to reduce low temperature embrittlement of stressed parts, particularly of parts which may be subjected to mechanical shock a t low temperatures. Copper, brasses, and bronzes, generally speaking, do not embrittle at low temperatures, Neither do the nickel-bearing stainless steels. Ordinary hot and cold rolled steels, however, do suffer appreciable reduction in impact resistance at low temperatures.” Allen and Mendoza (I) studied the thermal conductivity of copper and nickel silver at liquid helium temperatures. By extrapolation, it is predicted that copper should have a reasonable thermal conductivity at 0.1 K. and should still be in the metallic class. At 0.01 IC. it is predicted that the thermal conductivity of copper should be somewhat smaller than that shown by nickel silver at room temperature. Copper would also be a good thermal conductor in strong magnetic fields a t these low temperatures. Hidnert and Krider ( 2 1 ) have published the results of recent work concluded at the National Bureau of Standards on the thermal expansion of some copper alloys. Jaffee and Ramsey (96)also reported the linear coefficient of thermal expansion for several aluminum bronzes. Burghoff and Blank (9) have published the results of reverse bending fatigue tests on three types of copper, five copper-zinc alloys, and four other copper-base alloys. The effect of grain size, amount of cold rolling, and angle of applied stress relative to the rolling direction on the fatigue strength is also reported. The impact strength of aluminum bronze has been reported by Fontana and Zambrow ( 1 7 ) . Hutchinson and Reekie (93) have studied the temperature dependence of the magnetic susceptibility of annealed and cold worked copper over the range from 90” to 630” K. FABRICATION PROPERTIES
Lehrer ($1) has discussed annealing atmospheres and controlled atmosphere furnaces for copper and copper alloys and other nonferrous materials. A number of publications have appeared during the past year regarding methods of joining copper and copper alloys. York (55) describes a number of joints for thin walled tubes. A patent by Dillinger and Pattan (16)covers flame soldering where fluxing is accomplished b y entraining hydrogen chloride gas in the gas stream supplied to the torch b y bubbling the gas through a 35 to 37% aqueous solution of hydrogen chloride. I n another patent by Worrell(64) i t is claimed that improved wetting properties, less trouble from excessive drossing, and better flow are obtained in 80% lead-20% tin soft solders by the addition of 0.005 t o 0.05% zinc. It is believed that the benefit derived from the addition of zinc to the solder results from the interaction of this zinc with the hydrochloric acid-zinc chloride flux normally used in soft soldering, which provides an additional soft fluxing action. Simon (4s) discusses the mechanism of hard soldering with copper including methods of application, furnaces used, and mechanical properties of the soldered joints. It is shown that
Vol. 40, No. 10
the mechanical properties of these joints are dependent upon the time of soldering, quality of the surfaces, and the temperature, The importance of using deoxidized copper which is free of copper oxide inclusions and carrying out the brazing operation in a hydrogen atmosphere is emphasized. It is suggested that a good hard solder for copper, bronze, or brass is a copper-silver alloy Containing phosphorus melting at about 650” C. This corresponds to Grade 11 (80% copper, 15% silver, 5% phosphorus) in tlie A.S.T.RI. specification covering silver brazing alloys. This is a proprietary alloy which is sold under the trade name Sil-Fos. It has been reported that this self-flming silver. brazing alloy is also suitable for use in joining 70-30 cupronickel. A silver soldering alloy of copper, silver, zinc, and cadmium (corresponding to h.S.T.bI. Grade 12) melting at about 630” C. can be used for both ferrous and nonferrous alloys, but it is recommended that a flux be employed. This is e, proprietary alloy sold under the trade name Easy-Flo. Van S a t t e n (49) has described ten silver brazing alloys. Keith (26) has described in considerable detail the autornatio carbon arc welding of copper. -4general discussion of the welding of copper and copper alloys was recently given by Cook and Davis (14). Hose (22) describes the welding of silicon bronzc sheets to mild steel sheets using aluminum bronze electrodes. The carbon arc welding of a tank and cooling coil assembly of aQ electric drinking water cooler made of red brass (85% copper, l5y0zinc) using an inert gas-shielded arc is described by Benue (6). The red brass was heavily tinned before welding. Herbst (20)described the use of the inert gas-shielded arc method for welding silicon bronze and other nonferrous and ferrous materials. CORROSION RESISTANCE
Considerable information regarding the corrosion resistance of copper alloys has been summarized in the “Corrosion Handbook” edited by Uhlig ( 4 7 ) . Here the corrosion resistance of these materials is discussed with reference to fresh water, sea water, acids, bases, salts, gases, and the atmosphere. Buell and Boatright (8) have reported on the comparative corrosion resistance of carbon steel heat exchanger tubes and Admiralty tubes handling aldehydes in furfural extractive distillations. Under their conditions of operation, steel lasted on the average 6 to 12 months; whereas Admiralty lasted in this service over 3 years with no evidence of corrosion. Camp (IO) reports that certain sulfur Compounds, such as hydrogen sulfide, mercaptan, and carbon bisulfide are very effective inhibitors for controlling the corrosion of copper-bearing alloys in atmospheres containing ammonia and oxygen. The addition of these sulfur compounds to 10% aqueous solutions of ammonium hydroxide at room temperature lawered the rate of corrosion from 33 up to 98%, depending upon the sulfur compound added and the concentration. Cooke and Merritt (IS) concluded from their study of materials and finishes for tropical services that “brass is generally satisfactory when adequately nickel plated. Tin plate is also satisfactory but less resistant t o mechanical damage. Silicon bronze. and beryllium copper are moderately satisfactory without sub-. sequent finish, showing only tarnish under humidity conditions Under salt spray, they corrode similarly to other copper alloys. Nickel plate will provide protection.” The results of A.S.T.BI. Committee B3’s 10-year atmospheric corrosion test and datq from other sources have been summarized by Tracy (46),who, concludes that tough pitch copper, phosphorus-deoxidized copper, silicon bronze, tin bronze, red brass, niokel silver, and cupronickel can be used interchangeably for outdoor exposure as far as atmospheric corrosion is concerned. None of the alloys tested showed evidence of intergranular corrosion. However, as highly alloyed brasses are known to be subject to intergranular attack, dezincification, and season cracking, i t is suggested that they bc protected if exposed out of doors, or that some athor coppcr-base\
October 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
alloy be selected. Ray (41) gives typical analyses of copper and bronzes found a t Mohenjo-daro in Sind (Indus Valley civilization of 4000 to 3000 B.c.). Anderson (3) has discussed the mechanism of natural oxidation of copper, aluminum, and iron. Campbell and Thomas ( 1 1 ) have reported the results of their study of the oxidation of copper and copper alloys, nickel, and stainless steel a t 194”, 256”, and 302” C. The reaction of air with copper at elevated temperatures is the subject of a patent by Laird and Maxson ($9) on B method €or manufacturing nitrogen. I n this process, dried air is passed through a retort packed with copper wire a t a %emperature of 732’ C. to remove the oxygen. Ohlmann (36) has patented the use of finely divided rosin 0.1 t o 1 % or more by weight, which has been exposed to air and light, and 0.001 up to 0.1 % by weight of a primary monoamine dispersed in carbon tetrachloride to inhibit corrosion of copper and brass by wet carbon tetrachloride. The results of extensive corrosion tests conducted in chlorine and hydrogen chloride have been reported by Brown, DeLong, and Auld (7). Based on a corrosion rate of approximately 0.0025 inch per month a t 350” C., it was suggested that the upper temperature limit for eontinuous service for deoxidized copper in dry chlorine gas was 400’ F. Deoxidized copper was reported as igniting a t about 600”F. in chlorine. On the basis of an approximate corrosion rate of 0.0025 inch per month a t 200’ F., they suggested 200 O F. as the upper temperature limit for continuous service €or copper in dry hydrogen chloride gas. White (53) reports in Connection with the electrolytic production of chlorate that lead and steel pipe lines failed after a few months’ service carrying a potassium chloride-chlorate solution saturated with chlorine gas a t 50” C. This pipe line was finally replaced with thin-walled copper tubing which remained in service for over 18 months without any apparent damage from corrosion. Dlouhy and Kott (16) have described the use of a copperzinc alloy (95% copper, 5y0 zinc) hydrolysis coil in experimental corn sirup production over a 2-year period. The hydrolysis conditions were: ( a ) water, (b) 0.5% sulfuric acid, (c) water, (d)0.5% sodium hydroxide, (e) water, (f) blowout with steam, and finally ( 9 ) carbonaceous deposits removed from time to time by pumping 30 yo sodium hydroxide solution through the coils at elevated temperature and blowing the system out with steam. Tomashov and Timonova ( 4 8 have reported the results of an electrochemical study of the corrosion of copper, iron, and aluminum in 55% ethylene glycol solutions. This work indicates that cathodic polarization of copper and iron in 55% aqueous glycol is determined by depolarization by dissolved oxygen. Calculation of the potential drop in the local corrosion cell shows khat corrosion in such a solution is determined mainly by the cathodic depolarization. In connection with the corrosion problems encountered in fatty acid processing, Marsel and Allen (33)refer to the use of copperlined wooden tanks in connection with the Twitchell process and copper vessels in hhe bateh autoclave process. Banks’ (4) wosk on corrosion by flue gas vapors suggests that the corrosion resistance of copper is intermediate to that of the other materials tested. Booth, Davidge, Fuidge, and Pleasance (6),in their study of the corrosion resistance of tinned copper in flue gases, found that when the sulfur content of manufactured gas used as a fuel was reduced from 17 to 3 grains per 100 cubic feet, there was an almost corresponding reduction in the amount ,of corrosion on the gas side. A gas containing O.l.grain of sulfur per 100 cubic feet gave considerably more corrosion than that containing 3 grains. It appears, therefore, that the optimum sulfur content for the lowest corrasion rate is probably about 3 grains. During ithe past year, eonsiderable information was published regarding the production and handling of fluorine gas. Landau and Rosen (30)reported that eopper, brass (70% copper, 30%
1787
zinc), bronze, and 80-20 cupronickel showed good corrosion resistance a t 140” F. The corrosion rates ranged from 0.000011 up to 0.000024 inch per year. The corrosion rate of copper a t 930’ and 1290’ F. jumped from 0.2 to 3.0 inches per year, respectively. Murray, Osborne, and Kircher (34) described the use of copper gaskets, copper channels, and copper rods in the carbon anode fluorine cell. Gall and Miller (19) reported that fluorine gas “can be conducted in standard steel pipe or copper tubing a t atmospheric temperatures without noticeable attack, except for the formation of white scale on the interior surface and some corrosion a t the exit end of the pipe where it is exposed to atmospheric moisture.” Attention is called to the possible action of flexing or vibration that might flake or powder off the fluoride, which could then accumulate in restricted parts of the lines. Froning, Richards, Stricklin, and Turnbull (18) report that corrosion is not a serious problem in connection with the handling of fluorine gas, if moisture, including that due t o air and reactive contaminants such as grease and pipe dope, is kept out of the system. If not, not only does the system become fouled and clogged, but the quantity and disposition of the contaminants may be such that reaction with fluorine causes hot spots at which the kindling temperature of the metal is reached. When this occurs, all available fluorine reacts rapidly with the metal, causing it to melt and burst under pressure. A metal-fluorine flame is produced and pressure ejects molten metal and reaction products to a distance of several feet, with great danger to personnel Priest and Grosse (399)described the results of storing fluorine in pressure cylinders: On opening these cylinders after a year of use, no corrosion was noticed. The inside of the copper or nickel cylinders was covered with a thin, uniform film of copper or nickel fluorides, which evidently acted as a protective coating. A fluorine storage tank made of copper, nickel, or a copper-nickel alloy containing more than 60% copper is the subject of a patent obtained by Priest and Grosse (40). Mitchell (33) has discussed the use of copper alloy condenser tubes in oil refineries. A comment on the corrosiveness of lubricants toward copper in the new “Corrosion Handbook” (48) states: “Modern, wehefined lubricants give little trouble with copper. A copper strip test involving heating the oil in the presence of a copper strip, is extensively used, but often grossly misinterpreted. This test is used t o detect the presence of corrosive sulfur or sulfur compounds in lubricants. A black, scaly deposit indicates that the oil may corrode copper lines or copper alloy parts in service. Moderate staining of the strip, however, is no indication that corrosion of copper will occur in service.” Collins (12) has reported on the results obtained from piping handling saturated sodium chloride solutions a t room temperature. Although 60-40 brass (Muntz metal) was said to have dezincified after 10 years’ service, it has continued to give satisfactory service for the past 10 years. No failures were reported in copper lines in service for over 15 years. Ingelsent and, Storrow (34) have made extensive studies in connection with the corrosion of copper, brass, bronze, etc., filters in sugar refineries. Their studies indicated that numerous variations in potentials and polarity occur, depending upon the composition of the sugar liquors. For example, phosphor bronze, which is more anodic in glucose liquors at lower temperatures, has a strong tendency to become cathodic at higher temperatures. Wilkinson (53), discussing sulfuric acid corrosion in petroleum processes, concludes that for acid treating (2 to 10% sulfuric acid solutions in oils), either lead or copper alloys should be satisfactory. The report of Van Royen et al. (60)summarized the result of test installations in both cold and hot water extended over 12 water supplies representing the principal types of water occurring in Holland. I
Copper tanks containing from 0.25 to 0.45% arsenic are not objectionable. The higher the bicarbonate content of the water, the greater the amount of copper likely to appear in solution. The
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1788
dissolved oxygen content of the water is the most important factor governing the solution of copper from pipe walls. The pH is the next most important factor; the solution of copper is favored by a low pH. The use of untinned copper forthe transport and storage of hot and cold water is permissible if the walls are continuously in contact with water, unless the pH calculated from the free carbon dioxide and bicarbonate content is 6.9 or lower and the dissolved oxygen is over 3 parts per million. Tinned copper or copper with a tin lining can be used in doubtful cases. Pomfret and Mosher (38) call attention to the good service that can be obtained from copper piping in sea water at moderate velocities, but copper may be badly corroded by sea water at velocities of 5 feet per second or higher or at temperatures above 110’ I?. They report that wiped coatings of lead-tin solder on copper give considerable protection, but not against high velocities. Dipped tin coatings were considered ineffective. LITERATURE CITED
Allen, J, F., and Mendoza, E., Proc. Cambridge Phil. Soc., 44, 280-8 (1948). Am. SOC.Metals, “Metals Handbook,” 1948. Anderson, S., Phys. Rev.,69, 52 (1945). Banks, F. N., Gas, 23, 12, 64 (1947). Benua, L. P., Iron Age, 161,25,77-9 (1948) Booth, N., Davidge, P. C., Fuidge, G. H., and Pleasance, B., Gas World, 125, 720-1,730 (1946) ; 126, 146-50 (1947).
Brown, M. H., DeLong, W. B., and Auld, J. R., IND.EXG, CHEM.,39,839-44 (1947). Buell, C. K., andBoatright, R. G.,Ibid., 39,695-705 (1947). Burghoff, H. L., and Blank, A. I., Proc. Am. SOC.Testing Mateiials, 28 (1948). Camp, E. Q.,Proc. Am. Petroleum Inst., 27, No. 111, 153-66 11947). -. ,. Campbell, W. E., and Thomas, U. B., Trans. Electrochem. Soc., 91, 623-39 (1947). Collins, L. F., Power Plant Eng., 51, No. 12, 114-16, 132 (1947(. Cook, C. D., and Merritt, C., Jr., Chem. Eng., 54, No. 6, 77-80 (1947). Cook, M., and Davis, E., Trans. Inst. Welding (London), 10, 178-92 (1947). Dillinger, J. F., and Pattan, C. C., U.S . Patent 2,439,159 (April 6 , 1948). Dlouhy, J. E., and Kott, A., Chem. Eng. Progress, 44, 399-404 (1948). Fontana, M. G., and Zambrow, J. L,, Metal Progress, 53, No. 1, 97-101 (1948). Froning, J. F., Richards, M. K., Stricklin, T. W., and Turnbull, S . G., I S D . ENG.CHEM., 39, 275-8 (1947). Gall, J. F., and Miller, €1, C., Ibid., 39, 262 (1947).
(20) Herbst, H. T., Light Metal A y e , 6, No. 1 and 2,20-4 (1948). (21) Hidnert, P., and Krider, H. S., J . Research Nail. Bur. Standards, 39, 419-21 (1947). (22) Hose, H., Welding Engr., 33, 51 (1948). (23) Hutchinson, T. S., and Reekie, J.. Naiure, 159,537-8 (1947). (24) Inglesent, H., and Storrow, J. A., I n d . Chemist, 23, 827-34 (1947). Metal I.,Progresa, 54, No. 1, 57(25) Jaffee, R. I., and Ramsey, R. € 63 (1948). (26) Keith, It. B., Iron A g e , 161, No. 11, 160 (1948). (27) Kochendorfer, A., Metallforschung, 2, 173-86 (1947). (28) Kostenets, V. I., 9.Tech. Phys. (U.S.S.R.),16,515-26 (1946). (29) Laird, A. W., and Maxson, G . I., U.9. Patent 2,417,558 (March 18, 1947). (30) Landau, R., and Rosen, R., IND.EXG.CHEX.,39, 281-6 (1947). i Lehrer, W., Metal Progress, 53, 393-402 (1948). 1 Marsel, C. J., and Allen, H. D., Chem. Eng., 54, No. 6, 104-8 (1947). Mitchell, N. W.,Corrosbn, 3, 243-51 (1947). Murray, R. L., Osborne, S. G., and Kiroher, M. S., IND.ENB‘ CHEM.,39, 249 (1947). Nowick, A. S., and Machlin, E. S., J . Applied Phys., 18, 79-87 (1947). Ohlmann, E. O., U. S. Patent 2,387,284 (Oct. 23, 1945). Palmatier, E. P., Chem. Eng. Progress, 44, 481-8 (1948). Pomfret, R. A., and Mosher, L. M., Corrosion, 4, No. 5 , 2 2 7 4 3 (1948). Priest, H. I?.? and Grosse, A. V., IND. ENG.CHEM.,39, 279-80 (1947). Priest. H. F., and Grosse, A. V., U. S. Patent 2,419,915 (1947). Ray, P. R., J. Chem. Education, 25,337-35 (1948).
Seigle, L., and Brick, R. M., Trans. Am. Soc. Metals, Prepria$ 18 (1947).
Simon, G., Electrowarme, 11,47-51 (1941). Stauffer, Iz. A,, Fox, K., and DiPietro, W. O., IND. ENC.CHEL.
.~.
HARRY E. FISHER,
Vol. 40, No. 10
40, $20-5 (1948).
Tomashov, N. D., and Timonova, M. A., J. Phys. &‘hem, (U.S.S.R), 22, 221-31 (1948).
Tracy, A. W., “Symposium on Atmospheric Exposure Tests QE Non-Ferrous Metals,” Am. SOC. Testing Materials, 1946. Uhlig, H. H., “Corrosion Handbook,” 1st ed., pp. 61-112, Ne& York, John Wiley & Sons, 1948. I b i d . , p. 567.
Van Natten, W. J., Iron A g e , 161, No. 2, 51-5 (1948). Van Royen, R. P., et al., Report of Copper Pipes Committee, Netherlands Water Works Assoc. (1946). Voce, E,, Metalluryia, 35, 205, 3-9 (1946). White, N. C., Trans. Electrochem. Soc., 92, 295-301 (1947). Wilkinson, E. R., Corrosion, 3, 252-62 (1947). Worrell, G. H., IJ. S. Patent 2,439,068 (April 6 , 1948). York, J. E., Heating and Ventilating, 45, 84-8 (1948). RECEIVED August 23, 1948.
U . S . Industrial
Chemicals, I n c , , New York, N . Y .
TEADY progress in elastomers has been made this past year, although there have been no spectacular advances; oftentimes what appear to be spectacular advances are only the results of years of steady progress. T o r k has been reported on the theoretical aspects of natural and synthetic rubbers, on new rubbers, new methods of compounding, and new materials of reinforcement. Considerable work was done on improving the properties of synthetic rubbers and the products made from them, and on the testing of rubber products, especially under simulated service conditions. Many of these advances are mentioned or described in more or less detail below.. THEORETICAL STUDIES
The effect of temperature on resilience has been studied with a new apparatus called a piezoelectric pendulum (68) and many new
data have been obtained on vulcanixates of several syntheticl rubbers as well as of natural rubber. An extension of the sta-# tistics of liquid-elastomer mixtures gives explicitly the sorptioh isotherm of gases in elastomers a t temperatures above theii critical temperatures (5). Isotherms of a number of vapors ic rubbers have also been calculated. The specific heat of unvulcanized rubber at 25’ 6.did not change when the rubber was stretched through the range of 0 to 300% (51). On the other hand, the specific heat of vulcanized rubber, the stress iri which a t constant elongation increased linearly with rise in temperature, increased slightly with increase in elongation (0.002 calorie per gram per loo’%)? and the specific heats of other vulcanized rubbers at 25” C. did not change a t low elongations, but at approximately 200y0 elongation and above increased rapidly (0.015 to 0.020 calorie per gram per 100%). Relatively small, though technologically important, differences between
