x 783
IMDu
s'r R I A L
AND ENGIN EERIN G
in the brick lining (16,SO). For cxaiAiplc,steel sheet is pickled by a continuous process in tanks 300 fect long handling 2574 wlfuric acid at 210" t o 220' F. These 3OO-foot tanks have about 30 expansion joints inscrted a t regular intcnals in the brick lining. INDC STRIA L APP LICATXONS
It should be helpful to the chemical engineer to list some of the more imporrant applications of corrosion cements in various chemical industries. Brick-lined reactors, storage tanks, absorption towers, fume ducts, fume stacks, floors, sumps, trenches, manholes, and tanks for neutralization of wastes are used throughout the chemical industry in the production of acids, alum, corn products, copper sulfate, dyes, organic cliemicals and solvents, fertilizers, insecticides, pigments, plastics, and soaps. Practically all steel mills use brick-lined pickling tanks, stacks, floors, and tanks for neutralization of acid wastes. Food and beverage plants such as breweries, dairies, bakeries, and meat packing plants are using more and more acidproof tile floors joined with furan cement because of stringent sanitary requirements. I n pulp and paper mills, digesters, blowoff pits, process tanks, and floors are protected with brick linings joined with resin cements (4'7). The numerous applications of corrosionproof cements in rayon plants are shown in Table I, LITERATURE CITED
Ba,con, R. F., and Davis, €1. S., Chem. M e t . Eng.,24, 70 (1921). Chamberlain, J. M. W., C'hem. I n d . , XLIV, 401 (1939). Cordier, David E., and Baltz, Emil €I. (to Plaskon C o , ) , I : Patent 2,167,874 (hug. 1, 1939). Cornish, G. W., Organic Finishing, p. 26 (1946).
Delinonte, J., "Modern Plastics Encyclopedia," Vol. I, 73 (1947). Dietz, K., Greune, H., and PriT-insky (to Pen-Chlor, Inc,), c. S. Patent 2,255,546 (Oct. 7, 1942). Duecker, W.W., Chem. & -?!et. Eng,, 41,583 (1934). Duecker, W. W.,and Payne, C . R.,(to Texas Gulf Sulphur Co.), C . 8 . Patent 2,046,871 (July 7, 1936) Ibid., U. S. Patent 2,056,836 (Oct. 6, 1936). Dunlop, A . P., and Peters, F. bl., Colloid Cbem., 6, 1048 (1946). Ford, C . E., IXD. E R ' G . CHEM..39, 1202 (1947). and Hertrig, W. R., IND. ENG. Fragen, K . , Nysewander, C . W., CHEM., 40, 1133 (1948). Frank, K., and Diets, K. (to I. G . Farheriindustxie),TJ. S. Patelil 1,882,180 (oct. 4, 1233). ~
cBEM IsTR Y
Vole 40, No. 18
Frilz, H. E., a n d Elonvai~,J . j t . , Am. SOC.f ~ . i , Testirbg >dntc.ri&, Symposium on Rubber (1932). (15) Gates, E. B., U. S. Patent 2,015,470 (1935). (16) Heirs, Goo. O., JND.ENG.CHEM.,39, 1224 (1947). (i7) Rauth, 11. J. (to General Cable Corp.), U. S. Pa.tei-it 2,323,33:; (July 6, 1944). (18) Rier'er, E. P. (to Nationd Carbon co.), U. S . Pnt,ptlt 2,17)l.886 (October 3, 1940). (19) Klein, G. M., IWD.EKG.CHEM.,39,1234 (1947). (20) Klein, G. M., Modern Plastics, 23, 152M (1945). (21j McCulloch, L. ($0Westinghouse Elec. & Mfg. C o . ) , U. Y. ?:atent 2,032,142 (Feb. 25, 1936). ( 2 2 ) McNeill, J. J., Corrosion and MuteriaZProtect., 4 , 13 (I 947) ( 2 3 ) ?vfalm,F. S., Isn.ENG.CHEW,39, 1243 (1947). (24) Meier, E. F., Chem.. Eng., 54, 116 (1947). (25) Meigs, Curtis C., U. S.Patent 1,252,013(Jan. 1, 1918;. ( 2 6 ) Meyer, Emil, U. S. Patent 209,770 (1878). (27) Miihrle, Artur (to Xobert Bosch A-G.), U. 8. Patant 2,065,389 (Dec. 22, 1937). ( 2 8 ) Pa,yne, C. R., Chem. E n g . , 53, 116 (1946). (29) Payne, C . R., Municipal Sanitation, 7 (1936). ill Payne, C. R., U. S. Patent 2,085,165 (June 29, 1337) 1) Payne, C . R., and Dueclrer, W. W., Trans. Am. Insqt. C'hem. En.grs., 36,91 (1940). (321 Payne, C . R., and Severs, E. T. (to the Atlas Miiicral Products Co.), U. S . Patent 2,252,331 (Aug. 12, 1941). ( 3 3 ) Payne, C. R., and Seymour, R.B. (to theAt1asMine~:~lProdurts Co.),U. S. Patent 2,366,049 (Doc. 26, 1943). (84) Feteis, F. N., I X D . ENG.CHEM., 31, 178 (1939). (35) Portland Cement dssoc., BulE. RC5 (octohrr (1946). (36) .Chid., Bull. St. 4 (October 1946). (37) Ihid.,B d t . St. 17 (Xovember 1947). (38) Ihid.,Bull. St. 36 (October 1947). (39) Ihid., Bull. St. 57 (October 1947). (40) Ihid., Bull. St. 63 (February 1946). (41) Rauh, C. A,, ?'runs. Am. Inst. Chem. Engrs., 35,403 (1 (42) Runk, C . R., "Modern Plastics Encyclopedia," I.85 (4.3) Bchoenfeld, Frank K , ? T m n s . Am. Inst. Chem. E n g ~ . ,35, 447 (1939). (43) Snell, Foster Dee, U. S.Potent, 1,973,731(Sept,. 18, 1934). ( 4 5 ) Trickey, J. P., and Minor, C . H.,Ti. 8. Pat>ent,1,666,235iilpiil 10. 1928). (46) Ibid.. 1,665,237, (47) Tucker, E. F,, and Wcrking, 1,. C., T h e Fapci. 1n& World, 28, 60-3 (1946). (48) Vail, James G., A.C.S. Monograph 46, l-,t ed., Xew Y'ork, Chemical Catalog Co. (1928). (49) Wedge, Utley, U. S. Patent 1,220,875 (March 27, 2917). ( 5 0 ) Yeiton, Everett R., Chem. Eqg. Progress, 44.. 80 (January 1948). (14)
I
JOHN N. KOENXCT .I.
41utgers Ilnicersity. R'CIWBrunswick, A'.
HE classical whiteware body- for centuries has beeti composed essentially of a flux, a plaatic, and a nonplastic. The latter provides the skeleton held togcther by the glassy bond developed from the flux on firing. The plastic content provides for workability and castability rcquired in tlir various forming methods. I n general, more than one of the samc! type of material is used. The desired workability or castability is obtaincd from a mi\rti:rt. of clays of different particle-size distributions. One method of compounding a whiteware body of specific properties consists of first determining the plastic-nonplastic ratio which will give the desired workability for a spccific forming method, then adding flux in increasing amounts until the proper density is attained TYPICAL WHITEWARE BODIES 1,
High fired vitrifiedporcelains (1300O C. or higher) a. Industrial porcelains, chemical, sanitary, etc. b. Refractory porcelains, pyrometer tuhes, et?.
c. d,
Electrical porceluim, spark plug, high frequency insulation Normal porcefainfl, dinnerware
'L.
I'itiified whitewales (below 1300' C.) a . China dinnerware b. Sanitary ware c. Electrical porcelain, low and high tension insulators d. Vitrified floor tile e. Tender porcelains f, Miscellaneous
3.
Porous whitewares a. Semivitrified dinnerware b. Tableware c. Wall tile d. Misrellaneous
An appreciation of the general batch composition of typical whiteware bodies may be gained from Table I. Certain special and more recently developed whiteware ceramics constitute de.
October 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
partures from the classical and these are reviewed in subsequent paragraphs. There have been numerous new materials employed and innovations in methods of fabrication. The trend is toward firing ceramics at lower temperatures and developing the ceramic and glaze in a singlefiring operation.
Firing Temp.,
TABLE I. COMPOSITION OF WHITEWARES C.
1450 Refractory Porcelain
1300-1400 Chemical Porcelain 20-25 50-63 10-15 0-1
1300-1400 Normal Porcelain 20-28 40-50 22-35 0-1
1300-1325 1250-1285 Electrical Sanitary Porcelain Porcelain 32-38 30-36 35-60 36-55 15-25 20-30 0-3
Feldspar .. Clap 58 .. Flint Whiting or .. dolomite 45 .. .. Refractoryb a Mixtures of ball clays and kaolins required by various forming operations-e. g.. wet or dry processing, plastic forming, or casting. b Calcined kaolin, alumina, kyanite, sillimanite, and others.
..
..
The term "steatite" is given to the STEATITEPORCELAIN. low-loss electrical porcelain, containing a t least 70% of powdered talc; the balance is made up of materials such as clay and alkaline earths. Pure talc is a hydrous magnesium silicato, 3Mg0.4SiOz.H20. The final products of thermal decomposition of talc heated to 1300 C. are clinoenstatite and cristobalite ( 2 ) ; these crystals can be readily identified in the fired body. An excellent review of the constitution of steatite has been published (24). Steatite ceramics as referred to above are fired a t about 1350" C. Because of a relatively short firing range (25" to 30 O C.) close temperature control during the firing is prerequisite. The effect of certain cations of various valences in the glassy phase of a steatite ceramic on the final dielectric properties is of considerable interest (26). The alkalies show high dielectric losses which increase with increasing atomic weight. Divalent elements give low dielectric losses which are further lowered by increasing atomic weight. Trivalent elements generally give moderate power factors and dielectric constants. The rate of deterioration of dielectric properties with increasing temperature varies, depending on the specific materials involved (14). Commrrcial steatite porcelains (unglazed) for the greater part correspond to Grade L-4 and a few reportedly to Grade L-5 (6, 7). The range of typical low-loss steatite compositions is as follows: Talc Clay MgC03 BaCOa CaCOa Be0
60-85 5-17 0-17 0-24 0- 2 0- 2
Steatite ceramics are formed in various ways, such as extruding, machining, pressing, and slip casting. Where only a few pieces are required and the die cost is not warranted, several manufacturers fabricate such parts from soapstone or lava. Parts can be made with great accuracy because of the low shrinkage. Tolerances allowed on most steatite parts are * 1 or not less than 0.005 inch. Commercial steatites are characterized by high mechanical strength; the compressive strength may range from 65,000 to 90,000 pounds per square inch. Chiefly because of high thermal expansion (8 to 10 X in the range 20 ' to 600" C.), this ceramic has poor thermal endurance. The thermal shock resistance of steatite has been increased by the introduction of zircon as a crystalline phase (19). The best method of accomplishing this is by the use of a double silicate, preferably barium zirconium silicate as a flux in place of barium carbonate. ZIRCON PORCELAINS. Zircon has found limited use as an ingredient of high temperature porcelains for many years. The thermal endurance of the zircon porcelain (45 t o 60% zircon,
1183
balance clays and fluxes) is superior to the steatite porcelain and better than the normal electrical porcelain. I n general, zircon imparts strength, low thermal expansion, high thermal conductivity, high thermal endurance, and high chemical resistivity t o most ceramic systems (16). The alkali and alka!ine earth silicates of zirconia may be used to modify the properties as given in Table 11. Zircon and zircon-alumina compositions have been developed recently (19) which retain a flexural btrength of 32,000 pounds per square inch after 10 cycles from -56' C. for 0.5 hour to 850" C. for 10 minutes, followed by air cooling. These ceramics withstand more severe thermal shock tests than other high thermal endurant ceramics. Zircon has also found use in various porous type ccramics for applications requiring high thermal endurance. It is understood that the U. S. Metals Refining Company, Carteret, N. J., is preparing to offer for general commercial use a patented zircon-base ceramic which it has been using SUCCBBSfully for several years in connection with high temperature metal casting, etc. The material exhibits unusual resistance to thermal shock and is also unique in that it can be machined within final precision tolerances at a preliminary stage in its manufacture. Zirconia finds many uses in ceramics other than in porcelain bodies or refractories and refractory cements. Because of its high refractive index and insolubility in silicate systems, it is used as an opacifier in enamels and glazes. Zirconia provides an excellent base for chemical and heat precipitation of color oxides and tends to stabilize over wide ranges of temperatures colore normally difficult to develop and maintain. It is being used for polishhg glass in the field of precision optics. It has been used as an inert setter material for firing reactive ceramic bodies, for the stabilization of cordierite ceramics, and as an ingredient of welding flux formulas. CORDIERITE CERAMICS
The cordierite type ceramic body has found increasing application where refractoriness and high thermal endurance are required-e.g., heater elements. The low thermal expansion of this material (2.0 to 3.0 X low6for the range 20" t o 600' C . ) is the chief contributing factor to the unusually good thermal properties. Theoretically, the cordierite composition may be expressed as 2Mg0.2AlaOa.5SiOz (or approximately 14% magnesia, 35% alumina, 51% silica). This theoretical composition does not lend itself well to large scale production, owing t o a very short firing range when vitrified or nonporous. The commercial cordierites, therefore, have been porous ceramics containing the maximum amount of cordierite crystals that will provide a sufficiently long firing range (IS,2 2 , 2 3 ) . The variations in some properties of presently fabricated cordierite bodies are as follows: Flexural strength, lb./sq, in. Tensile strength lb./sq. in. Compressive strAngth, lb./sq. in. Absorption, % Dielectric strength, volts/mil Volume resistivity, ohms/cc. Dielectric constant
7000-12,000 3000-4000 30.000-50,000 10-15 100-150
I
> 1015
5-5 5
TABLE11. REPRESENTATIVE MECHANICAL AND PHYSICAL PROPERTIES OF ZIRCONPORCELAINS COMPARED WITH OTHERCERAMICS Zircon Porcelain (Low-Loss) 3.7 0 25,000
Steatite Porcelain 2.6 0 20,000
13,000
8,000
5,000
90,000
75,000
45,000
...
5.5 X 10-0
0.5 X,10-6
Specific gravity Absorption, yo Flexural strength, Ib./sq. in. Tensile strength, lb./sq. in. Compressive strength, lb./sq. in. Linear coefficient ,of thermal expansion (20" to BOO0 C . )
4 X 10-0 9 X 10-8
Electrical Porcelain (High Tension) 2.4 0 10,000
Fsised Silica 2.2 0
... ...
INDUSTRIAL AND ENGINEERING CHEMISTRY
1284
During the past two years dense cordierite bodies have been developed with a much longer firing rangc; thcsc ceramics should find wide usage. A notable extension of firing range has been achieved by prccalcination of a mixture of talc, magnesium carbonate, and clay, the desired composition is obtained by blending clays with the calcine (299). The best ceramic developed contains a very high percentage of cordierite crystals and has a thermal expansion of 0.88 X for the range 20" to 300' C. (fused quartz hias a value of 0.50 X within the same temperature limits). This ceramic fired a t about 1300" C. shows a n absorption of less than 0 1% and a firing range of approximately 40" C. This dense cordierite body possesses excellent strength, thermal endurance, and good electrical propertics. Confideration is also being given to the crystallization of cordiel ite from melts undzr varying conditions. A commercially frasible method has been devised (29) which will yield 90 to 100% cordierite or Cordierite solid solutions ceatered around 17% magnesia, 30% alumina, and 537, silica. TITANIA CERAMICS
Titanium rompounds have been used extensivelv in the production of the high dielectric constant ceramics for high frequency applicaticns-c.g., resistors, condcnsers of high capacity but of small size, trimmers, and temperature-compensating components I t is possible to make titanium dioxide ceramics with dielectric constants ranging from 110 to 6 and with temperature coefficients of negative, zero, or positive. The titanate compounds, such as magnesium, calcium, barium, strontium, zinc, and lead, provide for dielectric constants ranging up to and more khan 10,000. Some average values are: hlaterial Hear y grade Ti02 Calcium titanate Strontium titanate Barium titanate Barium strontium titanate
K Value of Ceramic 80
155 265 1400 4800
Proper forming and firing methods are essential as well as the absence of certain impurities such as zirconium, tantalum, chromium, cobalt, manganese, and nickel (1,11,36-$8) Titania ceramics are finding increased use as dielectrics, reeistors, photoconductors, etc., in the fields of radio, television, wire communication, power, motors, wave guides, elect] ical compensating dcvices, and photoelectric cells. Some of the properties on which the ceramic applications of titania depend other than electrical properties include: high refractive index (use in enamels, etc.), acid character of the oxide, ease of reactivity in ceramic systems, low melting of titaniatwaring fluxes, high degree of solvent action of these fluxes for metallic oxides, and general adaptability to forming by ceramic methods. Titania has been used for development of acid resistance and super-opacity in ceramic coatings. The titania content not only affords the required acid resistance but also yields outstanding reflectance values (67). Of importance is the fact that some of these super-opaque acid-resistant glasses can be applied to titanium enameling iron without blemish and without ground coat with no loss in acid resistance or opacity characteristics Titania ceramics have found considerable use in the manufacture of thread guides. Titania (rutile) and cei tain titanates have been employed for a numbrr of years as fluxes for coated welding rods. SPINEL-TYPE CERAMICS
Since World War 11 emphasis has been placed on the development of new ceramic materials of high mechanical strength, high thermal endurance, resistance to high humidity, corrosion, and growth of fungi, This Rork has included further investigation of certain existing ceramics-e.g , porcelains with high mullite content-as well as certain ceramic systems in which there has
Vol. 40, No. 10
been little or no previous experience. Along the latter lines, the field of magnesia spinel has been studied (20). Composit.ions in this field containing from 10 to ZOyo silica are of great interest. MOISTURE-REPELLANT CERAMIC SURFACES
Considerable work is under may to improve the water repellancy of ceiamic surfaces. Silicones, which have becn employed for this purpose, are not sufficientlv permanent. The best coatings produced to date contain lead oxide. Additions of bcryllium, manganese, copper, and other oxides are beneficial. Although alkalies arc gewrally harmful to these coatings in the presence of lead, this does not always hold true. Some of the best results have been obtained with alkali-bearing lead coatings, probahly because the lead ions hold the alkali ions tightly in the interstice of the lattice. Several other approaches in developing water-repellant bodies have met with success : self-glazing bodies and use of phosphate type glasses. Cordierite compositions provide excellent self-plazing structures. Glasses, which largely consist of phosphorus pentoxide provide effective surfaces for nonadhesion of water. The best results have been obtained by using a combination of a self-glazing body and a phosphate glass as the migrating flux (21). PORCEL4IYS OF HIGH THERMAL CONDUCTIVITY
An interesting investigation concerns development of ceramics with relatively high thermal conductivity. Of various compositions studied, some with high beryllium oxide content in the systems BeO-Al203-Th02 and Be0-81203-Zr02 with small magnesium oxide additions are of great interest (17). Although having the appearance of porcelain, these ceramics are essentially all crystalline. The mechanism of crystallization appears to br one of crystal growth rather than the usual formation of a glassy phase that fills or seals the pores. Some of these ceramics possess extremely high compressive strength. The molecular composition: 48 Be0-Al203-ZrO2 plus 4% magnesium oxide, fired at 1625 C., had a compressive strength of 275,000 pounds per square inch ( 3 ) . REFRACTORY PORCELAIXS
Much development work has been promoted in the field of ceramic bodies, aimed at entirely new whiteware applications, including turbines, jets, rockets, supersonic aircraft, and special electronic devices. Fundamental data are being sought on these mateiials in a large number of industrial and university laboratories GLASS-BONDED MICA
Glass-bonded mica, produced under vai ious trade names, is esscntiallyan aggregation of fine mica particles embedded in a glass matrix. A commonly used ratio consists of 60% mica to 40% glass, the latter generally lead borate or lead borosilicate. It is formed by compression molding, pressing a preformed blank to the desired shape, by transfer molding, or injection molding. This ceramic is available in sheet and rod form which can be machined readily (ordinary machine shop equipment for cutting, drilling, tapping, etc.). Fabricated parts may also be
TABLE 111.
PROPERTIES O F COMXERCIAL GLBSS-BONDED
PRODUCTS (10) Compression Molded
3.0 0.1
15,000 6,000 36,000
50 400
MICA
Injection Molded 3.8
13:000 6,000 20,000 150 400
October 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
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. CHEMICAL STONEWARE
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 t o enhance the thermal endurance of chemical stoneware (8,15). Physical properties of typical chemical stoneware and chemical porcelain are given in Table IV.
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 t o chemical stoneware in
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 (1940). 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). 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
