October 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
(30) Modern Plastics, 31, 91-9, 217-18 (April 1954). (31) lludge, W. L., Jr., “Zirconium and Zirconium Alloys,” pp. 146-67, American Society for Metals, Cleveland, 1953. (32) Piekervis, R. J., and Gonser, B. W., “Modern Uses for Nonferrous Metals,” 2nd ed., Chapter 21, American Institute of Mining and I\.Ietallurgical Engineers, New York, 1953. (33) Pershing. W. H., McClain, J. J., and Fulwider. J. A. (to General Motors Corp.), U. S. Patent 2,634,469 (April 14. 1953). (34) Rogers, R. R., and Fydell, J. F., J . EZectTochem. SOC.,100, 161.~4 (April 1953). (35) Ibid., 383-7 (September 1953). (36) Rostoker, W., Light Metal Age, 11, 11, 26 (October 1953). (37) Safranek, W.H.. Hespenheide, W. G., and Faust, C. L., Metal Finishing, 52, 70-3, 78 (April 1954). (38) Safranek, W. H., Neill, W. J., and Seelbach, D. E., Steel, 133, 102-4, 106, 109 (Dee. 21, 1953). (39) Safranek, W. H., and Faust, C. L., “Copper-Tin A4110yPlating,” presented at the Annual AMeeting of the Am. Electroplaters’ Soc., Xew York, July 13,1954. (40) Schickner, W. G., Beach, J. G., and Faust, C. L., S f e e l , 132, 11819 ( ~ a y 41953). , (41) Schmerling, G., Metal Ind. (London),81, 87 (June 12, 1953).
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2127
(42) Smith, A. A,, Jr., and Everhart, J. L. (to Am. Smelt. & Refining Co.), U. S.Patent 2,649,368 (Aug. 18, 1953). (43) Smith, H. V., Product Finishing, 6,42-8 (June 1953). (44) Smith, H. V., Rubber Age and Sgnthetics, 3 4 , 2 0 6 7 (July 1953). (45) Smith, H. V., Tin and Its Uses, No. 29, 7-8 (1953). (46) Speich, G. R., and Kulin, S. A,, “Zirconium and Zirconium Alloys,” pp. 197-207, American Society for LIetals, Cleveland, 1953. (47) Stones, A. E., Tde-Tech, 12, 62-4, 160. 163 (December 1953). (48) Tin andZts Uses, No. 28, 10-11 (June 1953). (49) Ibid., No 29, 1-5 (September 1953). (50) Zbid., No. 30,8 (May 1954). (51) Tin Research Institute, “1953 Report of the Tin Research Institute,” pp. 18-19, Tin Research Institute, Greenford, Middlesex, England, 1954. (52) U. S.Dept. Commerce, National Production Authority, Washington 25, D. C., “Materials Survey Tin,” 1953. (53) Vaid J.. and Rama Char, T. L., Carrent Sei. (India),22, 170-1 (1953). (54) Vogel, R., 2. Metallkunda, 44,3234 (July 1953). (55) Wilson, J. K., and Wright, O., Aircraft Prod., 15, 329-34 (September 1953). (56) Worner, H. W., J . Inst. Metals, 81, 521-8 ( J u l i 1953).
-~ -
WOOD
ROY H. BAECHLER AND ALFRED J. STAMM, Forest Products Laboratory, Forest Service, U . S. Department of Agriculture, Madison 5, Wis.
This review covers developments in wood products during the period April 1951 to April 1954. Sections on mechanical properties and on fiberboards are not included in this year’s report.
T
q t several years have seen no dramatic changes in the general practices of the wood-treating industry. A number of trends are noticeable, however, and several new development3 may ultimatelv prove to be of great practical importance.
PRESERVATIVE AND PROTECTIVE TREATMENT
Statistics ( 7 7 ) show a 4% increase in the wood-treating industry during 1952 compared with 1951. Of the products treated, wood blocks showed an increase of 35% and fence posts an increase of 30%. Pentachlorophenol solutions showed the largeEt percentage increase among the oil-type preservatives, and Chemonite among the water-borne preservatives. The total consumption of coal tar creosote, including solutions of creosote and coal tar, was approximately 227,000,000 gallons, of which approximately 67,000,000 gallons were imported. About 12,500,000 pounds of solid preservatives were used, which included somewhat less than 2,000,000 pounds of file retardants. Of the newer preservatives, Boliden salts, celcure, Chemonite, copperized chromated zinc chloride, and Greensalt were adopted as standard preservatives by the American Wood-Preservers’ Association (8). A relatively large number of papers were published during the past several years concerning the chemical composition, effectiveness, and methods of testing coal tar creosote. Mayfield (60) reviewed studies of the toxic constituents of coal tar creosote. Roche (66) listed 162 compounds found in creosote and pointed out that toxic compounds are found thrpughout the boiling range. Baechler ( 7 ) showed that all of the distillation fractions of low temperature-tar creosote are toxic due to the presence of tar acids, which on aeration undergo only a small loss in toxicity. Heicks and coworkers (42,43) reported on infrared, solvent extraction, and othcr studies of 16 creosotes of various types and sources. They described an x-ray technique for identifoing aromatic hydrocarbons in creosote and also a method bascd on differential solubility in p,p’-oxydipropionitrite for detecting petroleum in creosote. Andrews ( 4 ) shoived that some, but not all,
high boiling hydrocarbons in creosote depress the volatility of low boiling hydrocarbons, such as naphthalene. Most papers on the newer preservatives concerned pentachlorophenol. Duncan and Richards ( 5 0 ) published favorable results 011 creosote-petroleum-pentachlorophenol solutions tested in the laboratory b y the soil-blcck method. Duncan (28) also reported varied degrees of effectiveness for oil-tar creosote with and without pentachlorophenol> and for lignite-tar creosote with and without tar acids removed. Sedaiak ( 7 2 ) gave favorable results by soil-block tests on solutions of pentachlorophenol and copper naphthenate. Snoke ( 7 4 ) , with similar tests, showed t h a t if pentachlorophenol is added to creosote, a n increase in effectiveness may be expected. Progress reports were published for service tests being made on a large number of preservative materials by railroads, utility companies, and public institutions. A number of committee reports of this type appear in the Proceedinps of the Smerican Wood-Preservers’ Association and the Proceedings of the American Railway Engineering Association. Lumsden (63) summarized the condition of posts and poles treated with many materials and exposed for 25 years in a test plot in Mississippi. Blew and coworkers reported the latest inspection results of stake tests ( 1 6 ) being conducted in several locations and post tests ( 1 6 ) being conducted in Mississippi. H u n t and Snyder ( 4 8 )presented a progress report on stakes treated in 1928 and exposed in termiteinfested areas in Australia, Hawaii. Panama Canal Zone. and South Africa. Richards (66) gave a progress report on panels treated with various types of creosote and blends with coal tar and petroleum and exposed to marine organisms in t u o coastal installations. Graham ( 5 9 ) reported on the latest inspection of treated and untreated posts in a plot maintained by the Oregon Forest Products Laboratory Several noteworthy publications on the pressure-treating process appeared in the literature, including a revision of XfacLean’s ( 5 7 ) comprehensive treatise. Hudson (45, 46) described a method for recovering organic solvents from wood pressuretreated with solutions of pentachlorophenol or copper naphthenate that effects economies and improves paintability.
2128
INDUSTRIAL AND ENGINEERING CHEMISTRY
West (86) showed t h a t in treating southern pine posts that con, results can be obtained sist largely of easily treated s a p ~ o o dgood with pressures as lox as 15 pounds per square inch maint.ained for only 10 minutes. Mayfield ( 6 2 ) listed and discwsed 35 factors that influence the exudation of oil preservatives from wood. Rogers ( 6 7 ) found t h a t i t is practical to Boultonize certain ]Testern species a i t h pentachlorophenol solutions. McGehee and Van Allen (54) discussed the formation of emulsions and sludge iii petroleum solutions of pent,achlorophenol. Walt,ers (84)enumerated the factors involved in the blooming of pentachlorophenol; the character of the solvent is of special importance. Truax, Blew, and Selbo ( 8 0 )published t’heresults of st,udies of the gluing of preservative-treated x o o d and the t,reatnient of laminated wood after gluing. The number of papers on nonpressure treatments reflect a continued int,erest in such treat,nients, especially for products t h a t ore normally exposed to a nioderat,e decay hazard or for general use in areas where pressure-treated wood is not readily available or is unduly expensive. Further studies v-ere made of treatment b y cold-soaking of wood in limpid oil solutions of toxic chemicals, such as pentachlorophenol and copper naphthenate. Schnell (69) discussed some of the difficnlties and the effect of several factors on the re,suits. Raphael and Graham ( 6 4 ) presented data on the penetration of petroleum oils into Douglas fir heartlvood iTith a 15minute immersion period. Field studies conducted by Verrall ( 8 2 ) demonstrated the marked increase in the service life of xooden steps and porches t h a t could be obtained b y simple dip treatments of the lumber in oil-soluble preservatives. The profound effect of fungus infection on the permeability of wood was discussed by Lindgren (51) and by Blew ( 1 4 ) . Lindgren and Harvey ( 6 2 ) reported t h a t wood sprayed with sodium fluoride developed a heavy infection b y a commoii green mold that not only increased permeability, b u t also controlled attack by wooddestroying fungi, The latter effect v a s explained as antibiotic. Several published investigations concerned treatments in xhich the chemical entered wet n-ood by diffusion. Scheffer (58)added various chemicals to the bilge water of wooden boats in order to control decay of wooden members below the water line. Best results \\-ere obtained with pentachlorophenol and o-phenylphenol. Harroiv (40, 4 1 ) reported on diffusion treatments of tawa with boric acid. Baechler (6) described experiments on a double-diffusion t,reatnient designed to form insoluble toxic compounds by chemical reaction within the wood. -k simple set of directions (11)for treating fence posts by double diffusion was also published. -4tchley (6) and Baker (18) in separate papers reported t h a t by means of double diffusion treat,ments of redwood cooling towers shoxiiig decay, toxic precipitates may be deposited in the mood in retentions believed t o be adequate to prevent further decay. Cartwright, Edwards, and ~ I c 3 I u l l e n( 8 0 ) found that in the fumigation of timber, methyl bromide. 12 pounds per 1000 cubic foot for 96 hours, was effective. There was considerable activity in research ainied a t refining accelerated t e s k for evaluating preservatives. Duncan (89) studied several factors that affect results obtained by the suilblock method, including the density of the blocks, the weatliering d the treated blocks, and the culture period. Sedaiak (;Ye)also discussed details and limitations of the test. Eades aiid Roff (31 ) pointed out the desirability of controlling aeration in the soil-block test and recommended that a glass vent tube be incorporated in t h e lid of the bottle, Colley published a review ( 2 5 )of the laboratory methods that have been used and discussed (24) the correlation of results obtained by various laboratory and field tests. Jelley (49) reviewed research on the marine borer problem being conducted by the Department of the Kavy, Rureau of Ships, and described a method of assay that facilitates studies of the effective const,ituents of creosote.
Voi. 46, No. 10
TJYO foreign publications describd tcst methode employed i n Ensland ( 2 1 ) and Germany ( 4 4 ) . Several comprehensive books on v-ood preservation have appeared during the past several years (4?, 69,8 1 ) . The deterioration of wood in cooling t o m r s TTR? d i w m e d in a general way by a number of authors (12, 13, 26,$ 7 ) . It is generally agreed t h a t both attack by chemicals and decny produccd by living fungi may be responsible either separately or jointly, but the relative importance of the two agencie.5 or’ destruction remains a subject, of controversy. Controlling riie p1-I oi tiicl n-ater and especially avoiding the high pH values occasionally encountered is recognized as good practice. Bron.ning iind Buh1it.z ( 1 8 ) analyzed samples of rediTood shorving a number of diffeient types of deterioration and found marked diff erenctc in chemivsl composition. There has been considerable activity in the search !or coatings and impregnating materials to protect wood equipment from chemicals to which it may be exposed. T h e pubiiaiied informa,tion, however, has been meager. Volkening ( 8 3 ) stressed thr need for protective and preservative treatments of n.ood u w i iri chemical plants There chemical attack or decaj- may lead to p w mature failure. Baechler ( 1 0 ) summarized the advmtagcs of wood as a structural material in the chemical indu?ty: and gave data on the reduction in the bending strength of thin of six species exposed to a number of corrosive chemic FIRE-RETAKUANT TREATMESTS
Comparative fire hazard data for four different fire retud:tiits have been published (2), and tentative standard procedures for treating x i t h these chemicnls have been issued ( 3 ) . Aiigell (6j has published a paper covering fire testing and rating methods, together with data, formulations of file retardant:, building codes, uses for fire-retardant treated wood, and service records that should be of value t o the chemical engineer in deciding the lieetl for fire-retardant treated wood in various instances and in cho fire-retardant paints containing borax (35). G L U l N C .&NU LB,\lIN&TES
The use of glued wood assemblies in the forms of plyn-ood anti! lumber laminates has been expanding rapidly in rwent yeam T h e chief recent publication in this field is a U. S. Department ofi’ Agriculture bulletin entit’led “Fabrication and Design of Glued, Laminated Wood Structural Xembers,” by Freas and Selbo (38). This 200-page bulletin covers performance requiremeiitr, glue properties and selection, lumber selection, layout assemblies, gluing jigs and forms, gluing techniques, clamping and prepsurc. techniques, methods of curing, plant machinery requirements, coiitrol instruments, methods of evaluating the product, pixservative treatment of laminated wood and gluing of treated n-ood, basic features of laminated wood construction, calculatioii of working stresses, design considerations, and suggested Fperiiication requirements. I n article on adhesive bonded wood refrigerator cars (75) gives an excellent example of the wag in which glued-up wood construotion can be utilized by t,he engineer. Other examples of glued-up vood laminates are given in an article describing the new laminated wood nonmagnetic mine sweeper built by the S a v y and laminated wood military truck bodies built for the Ordnance Department (60). Durability of woodworking glues in different types of assembly joints have been studied by Selbo and Olson (73). Their study embraced 11 different glues representing six glue tgpee. The specimens were exposed to several different cyclic moisture content change conditions over periods of 3 years. Side-grain to
October 1954
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
side-grain joints were least affected b l moisture content changes, and the blocked joints were most affected. Under the most severe cyclic conditions, resorcinol and phenol-resorcinol glues were generally the most resistant t,o weakening. Summary recommendations by Committee 1-4 of the American Wood-Preservers’ Bssociat,ion have been made on the gluing of veneer and timber laminates t h a t have been previously treated wit,h preservative and fire-retardant salts (1). Treated lumber should be redried, then resurfaced just before gluing. Resin-film glues and hobpress phenolic glues are satisfactory for veneer treated with ammonium phosphate salts. Veneer treated with chromated zinc chloride is best assembled with a hot-press phenolic glue. For veneer treated with mixtures of borax and boric arid, melamine-fortified urea and urea glues may be used. Treated lumber laminates are best assembled with phenol-resorcinol and resorcinol glues. Blomquist (17’) discusses current investigations of durability of woodn-orking adhesives. Techniques for bonding metals and plastics t o wood are drsrribed by Tigelaar (79) and by Eickner and Blomquist ( 3 2 ) . Technical notes of the Forest Products Laboratery cover woodworking glues of natural origin (M), synthetic resin glues for wood (57), and chemical treatment of surfaces to improve joints with certain woods and glues (34). group of papers covering gluing techniques may prove useful to the chemical engineer. Marra (58) and Casselman ( 2 2 ) have malyzed plant gluing problems from the standpoint of developing practical, foolproof operations. Methods of controlling glue-line quality are discussed b y Phinney (63). Machining, handling, flow of materials, and control of gluing are discussed by Stanley ( 7 6 ) . The effect of moisture content and machining variables is discussed by Yavorsky ( W ) , who has also discussed electronic gluing (86). EFFECT OF HEAT
Ikvause wood used in various chemical erigineering operations is frequently subjected t o dry or moist heat, it is of considerable importance to know just what heat does to wood. MacLean (55, 56) has published two comprehensive articles on the subject. Thermal deterioration as manifested by weight loss is a temperature-time effect in which the time to attain a definite weight loss increases exponentially with a decrease in temperature. For the same temperature-time combinat>ion,deterioration is least under dry heat, more severe under steaming conditions, and still more severe under water-immersion conditions. Intermittent steaming is more serious than cont,inuous steaming. Hardwoods (deciduous species) are, in general, more subject to heat degradation than softwoods (coniferous species). Wood should not be exposed t o temperatures over 150” F. for prolonged periods of time. Two papers dealing with the chemical nature of heat degradation ( 6 2 , 7 0 )show t h a t the hemicelluloses of wood are first affected arid that the dimensional stability resulting from heating is not due to the formation of ether cross links as was previously supposed. DIMEN SIOi’i AL STABILIZATION
Little new information hap been published during the past three years on dimensional stabilization of wood. .4 process developed for the stabilization of fiberboard ($3) involving the treatment with alkyd resins is claimed t o be effective on wood. I t is hard to see, however, that it would have any advantages ovt’r phenolic resin-treated wood previously described. Tarkow and Stamm ( 7 8 ) have shown that high dimensional stahilization can be obtained by treating wood with formaldehyde vapor under acidic conditions. Unfortunately the p H has t o be about one or less. Under these conditions t,he wood is so severely embrittled t h a t no application of the process is anticipated. A paper by Seborg and Vallier ( 7 1 )describes the use of phenolic resin-treated mahogany veneer laminates (impreg) in die models
2129
and patterns b y the automotive industry. T h e impreg die models have proved to be so much more dimensionally stable than those made from mahogany lumber laminates in experimental tests, that they mag be adopted for general use in this industry. Mahogany impreg has also been successfully used in making crankshaft patterns from which repeated experimental shell moldings have been cast. In this application, advantage is taken both of the dimensional stability and improved heat resistance properties of the impreg. T h e pattern is heated for about an hour a t 400” F. The heat from the pattern then sets the rebin in the sand mold. S o r m a l wood would become badly charred after only a few cycles of use a t 300” F. The impreg patternhave withstood many cycles of repeated use. LITERATURE CITED
(1) Am. Wood-Preserters’ Assoc. Proc., 47, 184 (1961). (2) Ibad., p. 260. (3) Ibid., 48, 357 (1952); 49, 279 (1953). hndrews, John W., Ihid., 48, 85-97 (1952). Anaell. H. TV., Forest Products Research Soc. Proc., 5, 107 (1951). Atchley, Robert M., presented at 9th Southwest Regional Conclave, ACS, S e w Orleans, La., Dec. 10-12, 1953. Baechler, R. H., and associates, Am. Wood-Preservers’ Assoc, PTOC., 49, 12-17 (1953). Ihid., pp. 59-86 (1953). Baechler, R. H., and associates. J . Forest Products Research Soc., 3, 170-6 (1953). Baechler, R. H., and associates, presented at annual meeting of Forest Products Research Soc., Grand Rapids, Rlich., Xlay 5-7, 1954. Baechler, R. H., and associates, U. S. Forest Products Lab. Rept. 1955, 1953. Baker, D. R., presented at meeting of Oil and Gas Power Division, Am. Soc. Mech. Engrs., Kansas City, Mo., June 14-17, 1954. Baker, D. R., presented at seventh annual conference of the Petroleum Division, Am. Soc. Mech. Engrs.. Kansas City, &Io., Sept. 22, 1952. Blew, J. O., J . Forest Products Research Soc., 2, 85-6 (1952). Blew, J. O., Progress Report, U. S.Forest Products Lab. Rept. 1761, 1954. Blew, J. O., and Kulp, John, 1954 Progress Report, U. S.Forest Products Lab. Rept. 1757, 1954. Blomquist, R. F., ASTM Symposium on testing of adhesives for durability and permanence S.P.T. No. 138, 1952. Browning, B. L., and Bublitz, L. O., IND.ENG.CHEM.,45, 151620 (1953). Calif. Redwood Assoc. Interim Reports A to L, Proj. 5.31320, 1950-1953. Cartwright, J. B., Edwards, D. W., and RIcNullen, 31. J., X a t u r e , 172, 552-3 (1953). Cartwright, K. H. G., and Findlay, W. P. K., “Decay of Wood and Its Prevention,” XIV and 294 pp. Chemical Publishing Co., Brooklyn, N. Y . ,1950. Casselman, R. J., J . Forest Products Research Soc., 3, 32 (1953). Chem. W e e k , 73, 56 (April 4, 1953). Colley, K.H., J . Forest Products Research SOC.,4, 43-51 (1954). Colley, R. H., “The Evaluation of Wood Preservatives,” Bell Telephone System, Monograph 2118, 1953. Comeaux, Roy V., presented at midyear meeting of Am. Petroleum Inst., New York, iY.Y., May 12, 1953. Cooling Tower Inst., Palo Alto, Calif., Summary Report of Technical Committee No. 3, Bull. TSC-302, 1953. Duncan, Catherine G., Am. Wood-Preservers’ Assoc. Proc., 48, 99-104 (1952). Ibid., 49, 49-57 (1953). Duncan, Catherine G., and Richards, C. Audrey, I b i d . + 47. 26489 (1951). Eades, H. W., and LZolff, J. R., J . Forest Products Research Soc., 3 , 68-71, 94-5 (1953). Eickner, H. UT., and Blomquist, It. F., Forest Products Lab, Rept. R1768, February 1951. Forest Products Lab. Rept. 1443, 1953. Forest Products Lab. Tech. Note 232, revised August, 1953. Ibid., 249, revised December 1952. Ibid., 257, February 1953. Ibid., 258, February 1953. Freas, .4. D., and Selbo, M. L., U. S. Dept. Agr. (Supt. Documents, Washington 25, D. C., price 606.) Tech. Bull. 1069, February 1954.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2130
(39) Graham, Robert D., Oregon Forest Products Lab., Progr. Rept. 7, 1953. (40) Harrow, K. K., New Zealand J . S c i . Technol., 32B, N o . 4, 28-31, (1951). (41) Ibid., 33B, No. 5, 385-92 (1952). (42) Heicks, Ray E., Am. Wood-Preserters' Assoc. Proc., 48, 53-80 (1952). (43) Heicks, Ray E., Blum, Samuel E., and Burch, Joseph E., I b i d . , 49, 18-37 (1953). (44) Holsschutzmittel Prufung und Forschung I11 Rirsenschaftlich -4bhandlungen der Deutschen llateralprufungsaustalten, Berlin-Dahlem, I1 Folge, Heft 7, Springer-Verlag Berlin, 1950. (45) Hudson, M. S., Am. Wood-Preserzers' Assoc. Proc., 49, 146-68 (1953). (46) Hudson, 11.S., J . Forest Products Research Soc., 3, 177-82, 230-2 (1953). (47) Hunt, George M.,and Garratt, George A., "Wood Preservation," 2nd ed., McGraw-Hill, New York, 1953. (48) Hunt. George AI., and Snyder, Thomas E., Am. Wood-Presewers' Assoc. Proc., 48, 314-27 (1952). (49) Jelley, Joseph F., Ibid., 49, 215-28 (1953). (50) Kuenael, J. G., Poletika, K. V., and McIiean, H. B., J . Forest Products Research Soc., 3, 35 (1953). (51) Lindgren, Ralph bl., Am. Wood-Preservers' Assoc. Proc., 48,15868 (1952). (52) Lindgren, Ralph I f . , and Harvey, George 1I.,J . Forest P T O ~ U C ~ S Research Soc., 2, 250-6 (1952). (53) Lumsden, George Q., Am. Wood-Preserzers' Assoc. Proc., 48, 2 7 4 8 (1952). (54) McGehee, H. T., and Van Allen, R. G., Ibid., 48, 224-39 (1952). (55) hlacleau. J. D.. Ibid.. 47. 155 (1951). (56) Ibzd., 49, 88 (1953) (57) XacLean, J. D., "Preservative Treatment of Wood by Pressure Processes," U. S. Dept. of Agr. Handbook 40, 1952. (58) hIarra, A. A., Forest Products Research SOC.Proc., 5 , 256 (1951). (59) Nartinez, Jose Benito, "Conservation des Maderas en sus Aspectos Teorico, Industrial, y Economico," Vol. 1, Inst. Forestal d Investigaciones y Experiencios, Ministerio d Agric. Madrid, 1952. The (60) blayfield, P. B., Am. Wood-Pieselzers' Assoc. PTOC., 47, 62-85
Vol. 46, No. 10
Llayfield, P. B., J . Forest P r o i h c t s Research Soc.. 4, 52-5 (1954). LIitchell, R. L., Seborg, R. AI., and hlillett, M. A., Ibid., 3, 38 (1953). Phinney. H . K., Forest Products Research Soc. Proc., 5 , 268, (1951). Raphael, Harold J., and Graham, Robert D., Am. W o o d Preserrers' Assoe. Proc., 47, 173-5 (1951). Richards. A. P., I b i d . , 48,15-24 (1952). Roche, J. N., J . Forest Products Research Soc., 2, 75-9 (1952). Rogers, R. T., Am. W o o d - P r e s e r w s ' Assoc. Proc., 49, 40-7 (1953). Scheffer. Theodore C., J . Forest Products Research SOC.,3, 72-7 (1953). Schnell, Robert L., Ibid., 2, 80-4 (1952). Seborg, R. M.,Tarkow, H., and Stamm, A . J., Ibid., 3, 59 (1953). Seborg, R. M., and Vallier, A. E., Ibid., 4 (1954). Sedsiak. Henry, Ibid.,2, 260-8 (1952). Selbo, 31. L., and Olson, W.Z., Ibid., 3, 50 (1953). Snoke, Lloyd R., I b i d . , 4, 515-17 (1954). Snyder, F. H., and Plisky, C. J.. Ibid., 1, 3 (1951). Stanley, G. W., Jr., Forest Products SOC.Proc., 5 , 280 (1951). Steer, Henry B., Bm. Wood-PreseTaers' h s o c . Proc., 49, 291330 (1953). Tarkow, H., and Stamm, A. J., J . Forest Products Research Soc., 3, 33 (1953). Tigelaar, J. H., Ibid., 3, 41 (1953). Truax, T. R., Blew, J. Oscar, and Selbo, AI. L., Am. WoodPreservers' Assoc. Proc., 49, 113-120 (1953). Van Groenow, H. Broese, Rischen, H. W. L., and Van der Berge, J. "Food Preservation during the Last 50 Years," A. IT, Sijthoff, Leiden, Holland, 1951. Verrall, A. F., J . Forest Products Research Soc., 3, 54-60 (1953). Volkening, B. V., I b i d . , 3, 72-7 (1953). Walters, C. S., Ibid., 3, 61-6, 74-5 (1953). West, Richard F., Ibid., 2 , 85-8 (1952). Yavorsky, J. M., Forest Products Research SOC.Proc., 5 , 285 (1951). Yavorsky, J. >I., J . Forest Prodztcts Research Soc., 4 , 36 (1954).
U. S. Forest Products Laboratory is maintained a t hIadison, Wis., in cooperation with the University of Wisconsin.
(1951).
e
tals
W. R. BEKEBREDE ASD L. F. YNTERIA Fansteel .Metallurgical G o r p . , lYorth Chicago, Ill. This review of the past year's literature on the less common metals as materials of construction is divided into sections on titanium, zirconium, molybdenum, and tantalum.
T
HE past year's literature reveals a sustained interest in
titanium in spite of the fact t h a t during the first part of 1951 the supply of this metal exceeded the demand. This situation was attributed to rapid increases in sponge capacity and should be only temporary. The industrial uses of titanium are still quite small, awaiting a price reduction and improvements in oxidation and corrosion resistance. Considerable attention n-as paid during the past year to surface treatments and welding procedures. Also investigated were the corrosion resistance of titanium, its reactions with gases, and improved melting and casting methods, T h e zirconium literature x a s concerned with a n electrolytic method of production, the corrosion of zirconium in liquid metals, and its reactions with gases and refractories. .4n electrolytic process was also investigated for molybdenum. Information appeared on its corrosion behavior in liquid metals, and on a method of protecting molybdenum against Oxidation. T h e tantalum literature discussed corrosion in liquid metals and high pressure oxidation.
TITANIUM
-4double arc-melting method vias designed by Van Thyne and associates (33)to overcome the segregation normally encountered in commercial titanium-base alloy ingots. T h e first melting is done in a nonconsumable electrode furnace. The resulting ingot is forged to rod, which is used as the consumable electrode in thcl second melting. Homogeneity of ingots produced in this manner was checked b y chemical analysis, and the results iridicatrd that a good degree of homogeneity was achieved. Recent research at Battelle Memorial Institute for the Frankford Arsenal (3)revealed a possible method of using inexpensive and expendable materials for casting titanium. Interesting results xere obtained by using a zirconium oxychloride wash on silica shell molds. A mixture was prepared consisting of a saturated aqueous solution of zirconium oxychloride and a small amount of ethanol. This was brushed on the molding faces of silica shell molds t h a t were then baked a t 232" C. for 1 hour. The titanium m-as prepared in a skull-melting furnace under ar-
