Less Common Metals
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D. B. BROUGHTON L'niueraol Oil Products Company, Chicago, I l l .
T
tiE past year haa been notable chiefly for tho increasing volume of publishod information on methods of production, physicel properties, and corrosion resistance of ductile titanium and its alloys. Although the metal is atill available only in developmental quantities, its combination of desirable properLie8 points to widespread u x when lerge-seale lower cost producLion methods are developed. New data on the corrosion resist aiice of tantalum and ita alloys and on duotile zirconium have appeared. In the field of noble metals, little ocw information of industrid liignificanoe h w h e n published. TITANIUM
Refining procese~to produce commorcially pure metal powder &re describod by Wartman and eo-workers (49, 44), Worner (481, aod Anderson (e). Consolidation of the powder by hotrolling in waled metal containers to prevent ahsorption of oxygen and nitrogen is reported by Long (SI). Sutton (40) desoribes pn%duotion of 10.pound ingots by induction melting oi the powder in a graphite crucible in an argon atmosphere, and report@thiLt the mgots are readilymiiehined, hotforgcd, or hotmlled. Considerable new data have keen reportod on mechanical prop erties of the eornmercially pure mptal. Greiiier and Eilic (IO) report a coefficientof thermal exparisinn of 9 X 10-'per ' C., m electrical resistivity of 55 microhm-cm, and a relatively low thermoelectric power. Miehels and Wilford (56)have determined vdues of electrical resistivity and total emissivity up to 1400" K. Bickerdike snd Suteliffe (4) report the following values for tensile strength nnd elongation of ban produced by rintering, cold-hammering, and annealing at 800" C.:
I1
20 30U
,
33.2 Zb,3 16.6
17.3 12.2
500
abiy, but do reduce ductility. Adenstadt ( I ) reports B weep rate at room temperature of O.ooOl% a t SO% of the yield load for cold-rolled metal and st 50 to 60% of the yicld load for annealed metal, llod points out that these istee me x + ~ t i ~ e lhigh. y Cotterman (7) summarieea the mechanical properties of she& metal produced from iodide-reduced titanium, and oontrasts the metal with nluminum and stainless steel. Williirrns (45) reviews the meehsnieal properties of bar and sheet produoed by the Burenu of Mines process, and indicates that the metal has B relatively high yield ratio, B tonsile strength near that of medium steel, and B somewhat low resi8tance to fatigue. Du Mond (9) has summarized material present& st the Kava1 Iieseareh Symposium on methods of pmduetion and mechanical properties of the onmm~rciallypure metal. In a review srticle, Gonser (18) quotes tensile strengths and elongations of 40,000 pounds per square inch and 40% for iodide. reduced anneded meld and corresponding figures of 80,W pounds per square inch and 25% for m*gneium-reduced metal Hc points out that, by 60% cold reduction, a tensile strength of 12,6,000 pounds per square inch a t an elongation of 12% can be ubtnincd. He disewses methods of working the metal and pointti out that good mechanical properties are retained up to 800' F. Data on the optical metallography of mmmwciallv pure metal are prcscnted by Finlay, Resketo, and Vordnhl (11). Further r r v i e w ~have been published by Harwood (SI], Warner (48), Skwnrt (301,Litton (So),and Hetzig (d.91.
A t room tempmature, the elastic limit wa4 found to be 25.4 tons per square inch. Fuilcr ( 1 4 ) reports the following meohmice1 properties for wrought titanium at room temperature and at - 3 2 1 O F :
blndiilus. ib./ns. inch Tenrile rtieouth. ih./aq inrh Yieldstrenpth.Ih./s~.inoh hroa reduotion. % Eioncafio".
%
Yirkem hard"-8 C l , a r ~ yiinpaot ahuwtioo. ft.-iL
77' F. 16.7 X 1CP 8Y.050
1S.YB x 188,0011
72.150
177,000
21
27 5 209 lb.4
-221'P
la
I * 75 13.75 3 w 8.6
The effect of impurities on meehmierl properties is discus& by Jaffee and Campbell (M), who state that nitrogen is more potent in increasing hardnesr and strengt,h and decreasing than ~ y g m ductility of the mr,tal, whereas up to 1 atomic % hydrogen has little &ct. The= authors a h report that the metal car1 be cold-rolled to 9; % reduction without edgc cracking, if the oxygen content is below 0.25 atomic %. Finlay and Snyder ( I d ) have studied the &et of nitrogen, uxypn, und carbon on ductility, tendile strength, and hardness of high-purity annealed titanium. Gee, Sutton. m d Bar1.h (18) repert that csrbvn up to 1.2% has little effect on forgeability and rollability of titanium ingots a t suitable operating conditions. Amounts of carbon over 0.26% do not affect strength appreci-
Ifutehinaon and Peennilr (84) have summarized the results of testa on commcr&I titanium st the Kure Beach Marine Corrosion Testing Station. They report that no visual attack hss nccurred in 120 days' exposure to sea ~ p m yand marine a t m w phere. Likewise, no attaok is evident after 120 dnys under conditions of total submergence and exposure to an underwater jet carrying entrained air. Fouling organisms have grown OD sub. merged speeimons, but no wrrmion or pitting has oocurred undw the organisms. Tests, w yet inoomplete, are under way to i n w g tigste strew oorrosioo aod bimetallic effeots. The same authon ($4) report the results of 3W-hour laboretory corrosion tests in unstirred solutions in lwsely oovered wntainecl. They report B mmsion rate of below 0.Wl inch per year in aoetic anhydride, 28% ammonia, water saturated with hydrogen sulfide, 5% hydrochloric acid, 98% nitric Reid, aqueous
2024
INDUSTRIAL AND E N G l N E E R l N G C H E M I S T R Y
Vol. 42, No. 10
con, chromium, molybdenum, ,-garat.,
vanadium, Lon, 00bait, tungsten, carbon, and nitrogen. Long ($1) has studied the niokcl alloys, and indicates that useful allow may edst in the 6to 12% nickel range. I a m n and wworkers ($9) report phyaiwl properties of wrought alloys of titanium and earhrn with 13 other metals. Typioel physical properties me B tensile strength of 15c,OOO to 180,wO pounds per squere inch, proportional limit of 120,wO to 140,wO pounds per square inch, and elastic modulus of 16.6 to 17.8 X Iff pounds per square inch. A technique for caeting alloys with chromium, molybdenum, and tungsten is described by Braced al. (6). High temperature tensile data are given. Some of the alloys exhibited good oxidsr tion resistance in air up to Bw' C. Gonser [17) has discusred geoersl problems connected with produotion of useful alloys. Corrosion data on the alloy^ have not yet appeared. Darksdale (8) has published a monograph on titanium. One chapter, covering material published up to l%9, i a devoted to production, properties, and potential uses of the duotile metal. Potential use8 of titanium are discussed by Ralston and (krvenyak (SS),n'ilillirms (@), snd Litton ($0). Titanium is suggcuted for usa as an alloy where light weight and resistance to high temperature and corrosion are required, as a getter io elmtmn t u b a , for springs, gears, portable machine tools, mirror coatings, machine parte for the textile industry, maride parte,airwaft. snd ordnance (86): a180 far (18e BB DUD . . rods or rotor shafts under packing mate&& where stainlesssteel often pits (46), and in mobile equipment to fill the gap between pmperties of slumir u m and iron ($0). ZUICONlUM
*odium hypahlorite, 1% sulfuric acid, and h suapemiw, of suifu~ in water, ail a t room temperature Corrosion was likewise negligible in the following boiling solutions: W%scetie acid, 28% ealoium chloride, 40% oupric chloride, 10% sine chloride formaldehyde, ssturated sodium chloride, carbon tetr&chloride 01 trichloroethylene containing 1% water, and 100% stearic soid s t 180" C. No measurable Weight loss occurred but the metal was stained io chlorine w ~ t e r boiling , 10% chromic acid, boiling 10% femic chloride, and water sntureted with sulfur dioxide. The corrosion rate wag less than 0.005 inch per year in hot 30% ehloioacetic acid, boiling 85% lactic acid, boiling 10% sadium hydroxide and 40%sodium hydroxide st 80" C., and boiling 10% sodium sulfide. The metal wag relatively renqtive (>0.005 inch per yes?) to boiling 1% and o d d 10% hydrochloric acid, 1% hydrolluorio acid a t room tempersture, Imiling 65% nitric acid, hot 10% and cold 85% phovphorie acid, and >5% sulfuric acid s t t w m temperature. Taylor (42) reports the rrsulte of 36day laboratory ourroaiori tertr on aheet titanium. The metal was attacked at over 0.005 inch per year at room temperature by 18% and concentrated hydrochloric Reid, 50% srid concentrated sulfuric acid, &5% phosphoric acid, arid irydrofluoric acid. Very slight attack W I ~ E found with conceotratod nit,rir acid and with 10% ferric chloriiic a t mom temperature. Gee, PMden, and Lusby (15) have messured corrosion raw uf xsnenled and cold-rolled sheet in laboratory tests of up to 144 houm in aerated solutions of sulfuric, hydrochlorio, and nitric acids. Rapid nttaok W B ~found with 5% sulfuric and hydrochloric acids a t 35' C. and by lower concentrations at higher temperatures. Resistance to d l ooncentrations of nitric acid R t 35" C. wag excellent. The suthois also report exoellent resist atwe to aO% f u h g nitric acid. boiling glacial acetic wid, 10% sodium h.ydroride, and vsMus fruit juices. In thp held of titanium alloys, Crsighead, Simmons, and ICxstrood (8) have made a very extensive study of the mechanica1 properties of severs1 hundred bin-, ternary, and quaternary alloys with silver, lead, tin, nickel, copper, beryllium, bomn, si%-
The cost of ductile zirconium remains km high for widespresd However, the past year has men advance in produotion methods and additious to the litemtum on pmprtia of &e metal. Kroll and Stephens (B)describe B B-u of Mines pilot plant for production of 300 pounds of malleshle sirwnium sponge a week by magnesium reduction. Jaffee (W) haereviewedmetho& of production and properties of ductile airoouium. He points out that the ~trengthof the rolled or swaged metal is similar to that of the copperbase alloys and that the drawn metal has a tensile strength in the range of that of annealed medium-carbon steel. The strength-weight ratio of sirconium is below that of magnesium,titanium, or the atmng aluminum alloys. The 8suthor quotes corrosion dsta from the Foote Minerat Company which show B corrosion rate of less than 0.001 inch per yem in hot m d eold hydroohloric acid of all concentrations, hot and cold 10% sulfuric acid, hot snd cold nitric acid of all concentrations, hot and oold 10% phosphoric acid, and cold ooncentrated phosphoric mid. Attack was marked in hot and oold eonoentrated sulfuric wid, hot aqua regia, hot or cold hydrofluoric seid, and hot conrentrsted phosphoric acid. Resistance to aqueous and fused d u m hydroxide and potaesium hydroxide wae good. The metal was sttaoked by fused potaesium nitrate, chlorine water, and ferric chloride solutions. Gee el d.(16) report the results of 144hour laboratory corrosion tests on cold-rolled zirconium in miners1 acids. They 00"dude that, in sulfuric mid, attack is slight a t 35' C. below 80% concentration, but becomes marked a t 60' to 100' C. a t ooncentrations above 75%; resistance to hydrochloric acid st 100' C. below 20% mncentrstion is excellent; mistance to nitric acid at 35" C. a t ooncentrstiom up to 70% is excellent; resistance to phosphoric wid of all ooncentrations isexcellent st 35' to 60" C., but attack becomes appreciable st 100" C. above a concentration of 70%; aqua regis c 8 w 8 rapid attaok. Taylor (42)r e p & addition$ data on resistance to mineral acids, which show -ked sttaok by concentrated hydrochloric acid at llOD C. Hayes, Dilling, snd Roberson ($8) report physical propertk of rirconium st room temperature and a t -360' F. we.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Odober 19%
202s
TANTALUM
Techniques for fnbriehting tantalum by sintering and awsging, rollit>g,and drawing ere desoribed by Meyers (3% $$). The same author (34) wviews the physioal properties and constitution of nlloys with oolumbium. Aooording to Kaplan and Andrus (87), tantalum is resistant to red fuming nitric acid and to a mixture of fuming nitric and fuming sulfuric Reids between room trmperstuw snd 250" to 300" F. Taylor ( 4 1 ) mports that no attack w89 drtert;ible in laboratory corrosion tests up to 3G days in v&rious wmcentr;itions of hydrochloric, nitrio, phosphorio, and mliuric sei&. and in aqua ragis over R range of tempemtures. However, attack by hydrofluoric acid waa rapid. Rchurnh, Rildtkc, and Rever ($8) hnvo studied eormsiw m&t~ c i to : rniiiwitl acids of B wries oi tantnlum-molyljdenum ~lloys, pr~pnred1'y fuubn of sintered e o m p c t s in Z W ~ O N . The solutions were held a t 55" C. and saturated with oxygen L L ~1 Ntmosphet? pressurn. le 95.5% sulfurio acid, testr of 504-hour duration showed H. corrosion rate of shout I mg. per square dm. per d;ly for the molytdenenum-rich dloys, falling abruptly to zero when the tsntahm content wm inoreasod to 50 %tamis7%; in 37% hydmcrhlorie w i d , 2SO-hour teats showed negligible oorrwion for sllcrys mntaining above 60 atomic % tantalum; in 70% nitric acid,
330-hour tests showed rapid corrosion of the ntolybdenum-rich d b y ~ Idling , to zein above about 30 atomic % tantalum. NOBLE METALS
I A l e sew information has appeared. Pmhlieh (19) reviews u ~ e sof noble metals in the German ehemicel industry. Engelbard (IO)mviews production, phyaiclil properties, and cormsinn misistance of noble metals and their alloys. Review8 of the plstinum metals have also been published by Wim (46, 47) and Carter (8). Kaplan and Andm (t7) report that gold is not attacked by red fuming nitric acid or by mixtures of fuming nitric and fuming sulfuric acids up to 250' to 3co" F. Gretschm n n and Frijhlich ( W ) report a rate of attaok of 40% hydrciluoric acid on 99.08% silver from 0.002 mm. W Eyew at IS" C. to 0.M7*t 115' C. The eLmmmic usc of platinum pots to replace oeramic in the produetion of optical g l m is described by Roseh (37). LITEH*TUHI:Crmv (1) Adeustadt, H . . MrlaZP~oyresa,56,6%.-60 (1949).
(2) Anderaon. E. I,., U. (1949).
S. Bur. Mines. Repl.
h e a r . 4519,
37
PY.
w " 1 m " le,",*-*
A I U
(iW.rnl. ,at.
Titanium Wires with Diametcrs Ranging from 0.120 io 0.006 Inch (22) Hayes, E. T.. Dilling, E. D.. and Rehersan. A. H.. T ~ MA.m . Soc. Mefob. preprint No. 32, 22 pp. (1949). (23) Betais, R. A., Cham. Ape (London). 62, 7-2 (1950). (24) Hutchinson. G. E., and Permar. P. H., Carroaion. 5, 819-25
/._",. I1OALI
(25) Jaffee. R. I.. J . Melab. 1, No. 7. 6-8 (1949). (26) Jaffee, R. I . , and Campbell. I. E., J. Melala. 1, No. 9. Trans.. 646-54 (1919). (27) Kaplsn. N.. and Andius. R. 3.. IND. EN-. C~saa.,40. I(J467
~."~",. ,,O"P/
(28) K d l , W. 1..and Stephena, W. W.. Ibid., 42,395-8 (1950). (29) Lnrsen. E. 1.. Swasy, E. F., Buseh. E. L..and Freyer. 1%. N.. Ibid., 42,23742(1950). (80) LitMn. F. B., J . Eiecclroehem. Soc.. 97, No. 3, 6GC (1950). (31) law. J. It., "Report of Symposium on Titanium," pp. 2 7 ~ 4 8 . wonsored by Office of Yeval Research, Washington. D. C . .
."~". 1040
(3) Berksdale. J.. "Titnnium." New Ywk. The Ronald Preea a,, (82) Meyers. 11. H.. bfxtollur~io.38, 307-10 (1948). 1949. (33) Ibid., W 7 - 1 0 (1948). (4) Bickerdike. R. L.. and Su~oliffe,I). A.. Melollwgiu, 39, 303-4 (34)Ibid.. pp. 57--63. n l.llvn ,. r n i (35) Micheb. W. C.. arid Wilford. S.,J . Applied P l i g ~ .2,0. 1228 6 ( 5 ) Brace, P.H., Hurford. W.J.. atid Cmy, T H.. IND.b e . C H ~ M . . i,OdOi ~.".",. 42,227-36(1950). (361 I l d a t o r ~0.C:., m d Cael-vesysk.P.J.. IND. Em>.
