ENGINEERING RESEARCH INSTITUTE UNIVERSITY OF MICHIGAN ANN ARBOR PROGRESS BEPORT APPLICATION OF THE POLAROGRAPH TO ANALYSIS OF TITANIUM-BASE ALLOYS By PHILIP J. ELVING CHARLES L. RULFS ROBERT Wo PARRY GRAHAM A., STONER Project 2075 AIR RESEARCH AND DEVELOPMENT COMMAND, U. S. AIR FORCE CONTRACT NO. AF18(600)-397, E.O. NO. R606-60 SR-3z October, 1952

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ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN PROGRESS REPORT APPLICATION OF THE POLAROGRAPH TO ANALYSIS OF TITANIUM-BASE ALLOYS SUMMARY This report covers the period of August 7 to October 7, 1952. A "practical" or "working" bibliography of pertinent polarographic and chemical references on titanium analysis was prepared., and most of this literature has been examined. A summary 6f the available data on polarographic half-wave potentials for titanium and the principal titanium-alloying metals in various media has been prepared. The necessary chemical, polarographic, accessory electrical, constant-temperature, and other needed equipment has been assembled. Standard emicals and pure materials have been located and experimental work has been started. Research on the chemical analysis of titaniumbase materials in other laboratories has been investigated. BIBLIOGRAPHY ON TITANIUM ANALYSIS A. Polarographie Studies 1. Adams, E., Anal. Chem.> 20, 891-95 (1948). 2. Berl, G., ed., Physical Methods in Chemical Analysis, Academic Press, Inc., New York, Vol. II, 1951, p. 1-49. 3. Graham, R. P., and Maxwell J. A., Anal. Chem., 23, 1123-26 (1951). 4. Heyrovsky, J.> Polarographie, Springer-Verlag, Wein, Germany, 1944.

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN 5. Kolthoff, I. M., and Lingane, J. J., Polarography, Interscience Publishers, New York, Vol. I,, 1952. 6. Lingane, J. J., Anal. Chem., 21, 649 (1949). 7. Willard,, H, H., Meritt, L. L,,; and Dean, J. A., Instrumental Methods of Analysis, D. Van Nostrand Company, Inc., New York, 2nd ed., 1951, p 263-501. 8, Blazek, A., Anal. Chem, 24, 914-17 (1952). 9. Kolthoff, I. M,, and Matsuyama, G., Ind. Eng. Chem., Anal. Ed,, 17, 615-20 (1945). 10. Stern, A., Ind.. Eng. Chem., Anal. Ed., 14, 74-77 (1942). 11. Zeltzer, S., Collection Czechoslov. Chem. Commrun., 4, 319-334 (1932)> (English). 12. Caglioti, V., and Sartori, G., Gazz. chim. ital; 66, 741-44 (1956) ( Italian ) 13. Shportenko, P., Zavodskaya Lab., 7, 1431 (1938) (Russian). 14. Strubl,. R., Collection Czechoslov. Chem. Commun, 10, 275-492 (1938) (English). 15. Kalousek, M., Collection Czechoslov. Chem. Commun., 11, 592-613 (1939) (German). 16. Geller, B. A., Chem. Zentr.,- II, 1656 (1941). 17. Jessin, 0., O Chem. Zentr., I, 2776 (1941). 18. Zanko, A. M. Geller, B. A., and Nikitin, A. D., Chem. Zentr., II, 1656 (1941). 19. Zanko, A. M. et al., Zavodskaya Lab., 13, 299-300 (1947). 20. Lingane, J. J., Ind. Eng* Chem., Anal. Ed., 15; 583-590 (1943). 21. West, P. Wi, Dean, J., -and Breda, E. J.o Collection Czechoslov. Chem Commun., 135 1-10 (1948).

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN B. Selected Chemical Methods 1. Barksdale, J., Titanium, Roland Press Company, New York, 1949. 2. Furman, N. H., ed., Scott's Standard Methods of Chemical Analysis, D. Van Nostrand Company, Inc., New York, 5th ed.., Vol. I, 1939. 3. Thornton, W. M., Titanium, ACS Monograph Series, Chemical Catalog Copany, Inc., New York). 1927. 4. Hillebrand, W. F., and Lundell, G. E. F., Applied Inorganic Analysis, John Wiley and Sons, Inc., New YOrk, 1948, p. 452-462. 5. Lundell, G. E. F., Hoffman, J. E., and Bright, H. A., Chemical Analysis of Iron and Steel, John Wiley and Sons, Inc., New York, 1931, p. 352-58. 6. U. S. Steel Corp., zanpliln and Analysis of Carbon and Alloy Steels, Reinhold Publishing Company, New York, 1938, p. 182-196. 7. Willard, H, H., and Diehl, H., Advanced Quantitative Analysis, D. Van Nostrand Copany, Ihc., New York, 1943, p. 154-162. POIAROGRAPHIC HALF-WAVE POTENTIALS FOR TITANIUM AND ITS ALLOYING CONSTITUTENTS Supporting Electrolyte E1/2 vsE SCE Notes A. Titanium Ti4 in 0.1 N HC1 -0.81 Ti4 - Ti3 Ti4 in dilute NaOH N.R. Ti3 in 0.1 N HC1 -0.14 TiS-3 Ti4 Ti4 and/or Ti3 in -0.44 Ti4= — Ti3 acidified tartrate (reversible) Ti4 in 0.5 M H2S04 -0.30 B. Zirconium 0.001 M ZrOC12 in 0.1 -1.65 Preceded by N KC1 + ca. 0.001 N HC1 hydrogen wave at pH 3 Zr4 ->Zr(?) C. Nickel 1 N KCl -1.1 1 M NH40H + 0.2 N NH4C1 -1.02 1 N KCNS -0.70 0,5 M pyridine + 0.5 M -0.o78 pyridinium chloride 5

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN Supporting Electrolyte E1/2 vs. SCE Notes 1 N KCN -1.40 Ni2 Ni~ 1 M or greater neutral, N.R. tartrate D. Manganese Mn2 in 1 N KC1 -1.51 Mn2 |Mn Mn2 in 1 M NH40H + 1 N -1.45 NH4C1 Mn2 in 0.2 N KCNS -1.55 Mn2 in 1.5 N KCN -1.33 With smaller conc. of CN a second wave appears at -1.8 Mn2 in 0.2 M tartrate -0.4 Mn2 — Mn3 + 2 N NaOH -1.7 Mn2 > Mn MnO04 in neutral BaC12 (0.0) Wave starts at zero'potential ( -1.5 ) Reduction states not known E. Aluminum 0.05 N BaC12 or KC1 -1.75 F. Bismuth Bi3 in 0.1 N H2S04 -.o04 Prob. Bi3-4Bi Bi3 in 0.1 N HC1 -0,o8 Bi3 in 0.1 N HNO5 -0.01 Bi3 in 0.3 M tartrate at -0,29 pH 4.5 Saturated Bi(OH)3 in 1 N KOH -0,6 G. Cobalt Co2 in 0.1 N KClor NaC1 -1.20 Co2 in i N NH40H + 1 N NH4+ -1.30 Co3 in 1 N NH40H + 1 N NH4+ -0,3 Co3 > CQ2 -1.3 Co2 -— > Co Co2 in 01ol M pyridine + 0.1 -1.07 pyridinium chloride Co2 in 1 N KCNTS -1.Q03 Co3 in 1 N KCN -1.25 Co3 -Co2 Co2 in 1 M tartrate sol'n -1.6 H. Iron Fe3 in HC1, HC1, HC104, etc. Diffusion current of Fe3 - Fe2 obtained at zero applied emf, 4

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN Supporting Electrolyte E1/2 vs. SCE Notes Fe2 in 0.1 N KC1 or BaC12 -1, 3 Fe2 > Fe Fe2 in 1 NH4C104 -1.45 Fe3 and/or Fe2 in 1 M -o0.24 Fe3 _ Fe2 potassium oxalate (reversible) Fe3 in 1 N KF -1 3.6 Fe3 -— Fe2 Fe3 in 0.5 M sodium citrate -0.35 Fe3 >F-e2 Fe3 and/or Fe2 in alkaline -0.9 Fe3 = Fe2 tartrate solution (reversible) Fe3 in 1 M (NH4)2 Co3 -0.44 Fe3 >Fe2 -1.52 Fe2 -> Fe2 Fe3 in 1 N KOH + 8% mannitol -0.9 Fe3 - Fe -1.5 Fe2 - Fe Saturated Fe(OH)2 in 1 N NaOH -1.46 Fe2 -- > Fe4 Fe(CN)6 —' in 0.1 N KC1 (+0.2) Fe(CN6 -Fe(CN)6 I. Chromium Cr3 in 0.1 N KC1 or NH4C104 -0.88 Cr3 — Cr2 -1.53 Cr3 in sat. tartaric acid -1.00 Prob. Cr3SCr2 Cr3 in 0.1 M pyridine + 0.1 N -0.95 *pyridinium chloride CrO[-in 1.N NaOH -0.85 Cr6 > Cr3 CrO0-in 0.1 N KC1 -0.3 -10 car6 -— > Cr3 -1.5 Cr3 > Cr2 -1.7 Cr2 > Cr CrO4-in 0.1 N NH4C1 + -0.35 Cr6 Cr3 NI40H at pH 8 to 9 -1.7 Cr3 - Cr J. Tungsten W6 in neutral or alkaline N.R. medium W6 in 10 N HC1 -0.42 reduction state not known K. Vanadium V3 in 0.01 N HC1 + 0.1 N KC1 -0.85 V3 -> V2(?) V5 (NH4VO3) in 0.1 N HC1 (0.0) v5 > V4 -0.8 v4 -> V2 V03 in 0.1 N LiOH (-4.7) V03 in 6 N NH40H + 0.2 -1.6 V5 > V2(?) N NH4C1 5

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN SUMMARY OF RESULTS A. Assembly of A-paratus While automatic-recording instrumentation may be desirable at a later stage of the investigation, a manual-type Fisher polarograph (Elec.dropode) has been calibrated (galvanometer shunts and potential scale) for the exploratory runs. The "H"~style cell with a saturated calomel reference electrode and water jacketing on the solution side will be emloyed A constant-temperature bath using a circulating pump, a fixed-setting thermostat, and a Fisher-Serfass electronic relay is being employed for the temperature control. Temperature, at present, will be maintained at 25 + O.1~C; but the fixed-temperature regulator is easily exchangeable for work at other temperatures. B. Preliminary Study of Titanium Solutions Standard samples of titanium dioxide and titanium alloys were obtained from the National Bureau of Standards. A 5 mM stock solution of titanium was prepared from the standard TiO2. A trial polarogram was run on an aliquot portion of the stock solution in a 0.1 M sodium fluoride medium as supporting electrolyte. The polarogram shows a well-defined wave at approximately -0.14 volts vs. SCE. The dissolution of TiO2 materials proceeds with some difficulty, and the choice of solvents is limited. This is undesirable for our purposes, since it predetermines and limits the number of polarographic supporting media which could be examined. A small speciman of Foote Mineral Co. 99.99o titanium metal bar has been obtained (and more is on order) to furnish the titanium background for testing the polarography of alloying metals in a variety of media. C. Current Status of Titanium Analysis At the present time a variety of agencies are interested in the determination of the minor constituents in titanium metal and in titanilumbase alloys. Although it was believed that only slight use was being made of polarographic technique, it seemed important to ascertain the present knowledge on the chemical analysis of titanium materials. Accordingly, daring August and Septemer an attempt was made to learn by extensive correspondence the present status of work on the analysis of titanium-base; - - ~~~~~~~6

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN alloys and titanium metal. which is being sponsored by the Navy and Army Departments of the Department of Defense, Letters were exchanged with Watertown Arsenal, which is sponsoring and coordinating research on methods of analysis of titanium and its alloys. In addition, letters and one personal visit were exchanged with six industrial and arsenal laboratories working on the general problem. Watertown Arsenal has fully approved cooperation with us on the part of its contractors. As a result, we have received copies of a considerable number of analytical procedures for the photometric, gravimetric, and titrimetric determination of minor constituents in titanium-base materials, which will be of considerable help to us in the preparation of.solutions for polarographic investigation' FUTURE WORK We propose to examine the following possibilities in the order named, within the period of the next two to four months. (l) The polarography of titanic solutions in a variety of supporting electrolytes in order to ascertain how many of the alloying metals would be determinable at more positive potentials than the titanic/titanous reductionwave in each medium, (2) Conditions for the quantitative reduction of titanium to the Ti3 stage in various media, and the relative difficulties of maintaining the reduced state in each case. (3) The polarography of titanous solutions in various media and the separation of the waves of alloying metals from the ous/ic oxidation and from the ous/metal reduction. We shall try to correspond and cooperate- in every way possible with all other projects concerned with analysis of titanium, 7

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