1098
ANALYTICAL CHEMISTRY Table V.
Element
D a t a from Recovery Experiments Amount Added P.p.m.
Amount Found P.p.m.
Error
7c
could be checked spectrophotometrically were determined by the chemical analytical group, and the results from the two procedures are compared in Table IV. Included in Table V are typical results from recovery experiments in which known amounts of the impurities in question were added to a beryllium oxide base which had been previously analyzed. The results in Tables 111, IV, and V indicate that adequate accuracy and piecision can be achieved b y this method. Table I11 shows that the intensity ratios did not change significantly when the emulsion type n-as varied. It is therefore possible to increase the sensitivity for most elements by using faster plates. The concentration range can also be increased by using a low contrast plate such as Eastman Spectrum Analysis So. 2. The high dispersion of the spectrograph used in this investigation is not an essential requirement for these analyses; the method should therefore be adaptable t o any instrument of moderate dispersion. It should also be possible to extend the method to the determination of most of the metallic inipuriticin beryllium and its compounds. ACKNOWLEDGMENT
The authors wish to thank C. E. Reed for his assistance with the experimental work and A. B. Carlson for performing the spectrophotometric analyses. LITERATURE CITED
(1) Archihald, E.H., “Preparation of Pure Inorganic Substances.” p. 86, New York, John Wiley & Sons, 1932. (2) Ayers, B. O., and Fassel, V. A., CC-2940 (Dee. 31, 1945)*. (3) Cholak, J., and Story, R. V . . J. Optical SOC.Am., 32, 502-5 (1942).
Churchill, J. R., IND. ENG. CEIEM.,ANAL.ED.,16, 653-70 (1944). Cline, W. D.. and Warf, J. C., CC-2723 (June 30, 1945)*. Curtis, C. W., Phys. Reu., 53, 474-81 (1938). Dietert, H. W., and Schuch, J., J . Optical SOC.Am., 31, 54-7 (1941). Fassel, V. A., and Wilhelm, H. A,, Ibid., 38. 518-26 (1948). Geller, G. E., Yavorsky, P. J., Steierman, B. L., and Creamer A. S., J . Research Natl. Bur. Standards, 36, 286 (1946). Harrison, G. R., “M.I.T. Wavelength Tables,” New York. John Wiley & Sons, 1939. Jarrell, R. F., J . Optical SOC.Am., 32, 666-9 (1942). Kawecki, H., TTan8. Electrochem Soc., 89, 229-36 (1946). Kiess, C. C., J . Research Xatl. Bur. Standards, 21, 185-205 (1938). Kjellgren, B., Trans. Electrochem. SOC.,89, 247-50 (1946). McLennan, J. C., and McLay, A. B., Trans. Roy. SOC.Can., 20, 111, 89-120 (1926). Meggers, W. F., J . Research Natl. Bur. Standards, 24, 163-73 (1940). Pierce, W. C., and Nachtrieb, N. H., IND. ENG.CHEM.,A N ~ L ED., 13, 774-81 (1941). Raynor, G. V., J.Roy. Aeronaut. SOC.,50, 390-400 (1946). Richardson, D., “Proceedings of 5th Summer Conference on Spectroscopy and Its Applications,” pp. 64-70, New York. John Wiley & Sons, 1938. Russell, H. N., and Moore, C. E., Trans. Am. Phil. SOC..34 111-79 (1944). Schuch, J . , J . Optical Soc. Am., 32, 116-18 (1942). Scribner, B. F., and Corliss, C. H., J . Optical SOC.Am., 33, 515-18 (1943); J . Research Aratl. Bur. Standards, 30, 41 (1943). Scribner, B. F., and LMullin, H. R., Ihid., 37, 379-89 (1946). Smith, A. L., CC-2941 (June 22, 1945)*. Smyth, H. D., “Atomic Energy for Military Purposes,” Paragraphs 2.10, 2.36, 4.19, 4.20, and 6.22, Princeton, N. J.. Princeton University Press, 1945. Tornkins, F. S.,and Bubes, I. S.,CC-1325 (Feb. 1, 1944)*. Tomkins, F. S.,Cressman, G. W.,arid Tolmsch, L. J., CC-3524 (May 27, 1946)*. Van duwers, O., et al., “Beryllium, Its Production and Application,” pp. 5-96, New York, Iteinhold Publishing Corp., 1932. *Scientific reports of the Manhattan Project and the Atomic Energy Commission. RECEIVEDOctober 1, 1948. Presented before the Division of Analytical and Micro Chemistry st t h e 114th Meeting of the . i M E R I C A K C H E M I C A L S O C I E T Y ,St. Louis, Mo. Contribution 30 from the Institute for Atomic Research, Iowa State College. W o r k performed under contract W-7405 eng-82 for the Atomic Energy Commission.
Colorimetric Determination of Columbium and Tungsten in High-Temperature Alloys ISIDORE GELD AND JACOB CARROLL Material Laboratory, New York Naval Shipyard, Brooklyn, N. Y .
T
HE authors recently had occasion t o analyze high-temperature alloys containing both columbium and tungsten. The separation of these elements b y classical methods was a difficult and tedious procedure. Because tungsten accompanied columbium in precipitation reactions, i t was most difficult t o obtain a clean-cut separation of these elements, in one precipitation. Hillebrand and Lundell (Y), referring to the separation of the mixed oxides of columbium and tungsten, state, “Extraction of the mixed oxides with ammonium hydroxide or ammonium sulfide, or extraction with water after a fusion with sodium carbonate and sulfur are all unsatisfactory, as are also the boiling of an alkaline solution of the tungstate, columbate, and tantalate with ammonium nitrate or treatment of the alkaline solution with magnesia mixture.” Referring to the separation of columbium
from tungsten, using cupferron in a tartaric acid-sulfuric acid solution, they maintain, “Tungsten is partially precipitated no matter how much sulfuric and tartaric acids are used.” T o avoid such lengthy and tedious separations with their inherent possibilities of error, attention was turned t o eliminating separations of columbium from tungsten by determining both elements colorimetrically from the same solution. A solution of columbium and tungsten in concentrated sulfuric acid (11, 1%’) was found well suited for such colorimetric determinations. I n accordance with the work of Klinger and Koch ( 8 ) , columbium was determined in an aliquot of this solution by means of the yellow percolumbic acid produced by hydrogen peroxide. Titanium interfered by also producing a yellow color with hydrogen peroxide in concentrated sulfuric arid. Thanheiser ( 1 7 ) mini-
V O L U M E 2 1 , NO. 9, S E P T E M B E R 1 9 4 9
1099
A method is presented for the colorimetric determination of moderate quantities of columbium and tungsten in high-temperature alloys. Columbium is determined as the yellow percolumbic acid produced by the action of hydrogen peroxide upon solutions of columbium in concentrated sulfuric acid. Tungsten is determined as the yellow thiocyanate resulting from the action of stannous chloride and potassium thiocyanate upon solutions of tungsten. The interferences of other elements found in high-temperature alloys are discussed. The method is rapid and the accuracy is equal to that of gravimetric procedures.
niized this interference by the use of phosphoric acid. In the present work, this interference of titanium was also reduced but nithout the use of phosphoric acid. Then, based upon the investigations of Feigl and Krumholz (b), a method was developed for determining tungsten from another aliquot of the same solution. This was accomplished by means of stannous chloride and potassium thiocyanate, which produce the yellow tungsten thiocyanate in a lower valence state. Various modifications of the Feigl and Krumholz procedure have been reported ( 3 , 4 , 6 , 1 S , 14-16,18, $0). I n these investigations potassium thiocyanate was first added to the tungsten solution, then stannous chloride. (Some workers preferred using titanous chloride instead of stannous chloride to hasten the color development.) Gentry and Sherrington (6) found that by employing these methods little precision was obtained, as the tungsten was not reduced t o a definite valence state by the stannous chloride prior to the formation of the thiocyanate complex. They modified the procedure of Feigl and Krumholz ( 2 ) by first reducing the tungsten to a definite lower valence state by stannous chloride solution and tin amalgam, and obtained good precision. However, columbium was also reduced and formed an intense yellow color with potassium thiocyanate. The present authors also observed that when potassium thiocyanate was added to the tungsten solution, followed by stannous cliloride, even under exactly identical and rigorously controlled conditions the colors obtained varied from a bright yellow to a yellowsh green, with correspondingly varying colorimeter readings. When, however, the tungsten solution was first boiled with stannous chloride for a minute and cooled, and then potassium thiocyanate was added t o the cold solution, excellent precision was obtained and the color a t all times remained a bright yellow. Here tl e tungsten was also reduced t o a definite valence state. However, unlike the method of Gentry and Sherrington (6), the columbium was not reduced and therefore did not interfere with the colorimetiic determination of tungsten. The proposed proceduie for the colorimetr ic determination of columbium and tungsten is comparatively rapid and involves but two srparations. First, the oxides of columbium, tungsten, ailicoii, some molybdenum, and some titanium are separated by fuming with perchloiic acid, diluting, boiling with sulfurous acid to hydrolyze the columbium ( I ) , and then treating with cinchonine t o effect a more complete recovery of tungsten ( I ) . Secondly, after solution of the mixed oxides in concentrated sulfuric acid, the solution is diluted with tartaric acid solution and the molybdenum is precipitated with hydrogen sulfide (19). The filtrate, containing columbium, tungsten, and some titanium, is taken to fumes of sulfuric acid, first destroying the tartaric acid. Without further separations, tungsten and columbium are then determined colorimetrically in aliquot portions of the resulting sulfuric acid solution. APPARATUS
A photoelectric colorimeter such aa the Klett-Summerson, with a 420 millimicron filter and a test tube cell, was used.
SPECIAL REAGENTS
CINCHONINE SOLUTION.Dissolve 125 grams of cinchonine alkaloid crystals in 200 ml. of dilute hydrochloric acid (1 to 1 by volume). CIXCHONIXE WASH. Dilute 30 ml. of cinchonine solution to 1 liter with distilled water. STANNOUS CHLORIDE REAGEXT. Dissolve 50 grams of C.P. stannous chloride crystals in 100 ml. of hydrochloric acid (38%). Warm if necessary. The soIution must be clear. Dilute to 500 ml. with hydrochloric acid (38%). POTASSIEM THIOCYANATE REAGENT. Dissolve 25 grams of C.P. potassium thiocyanate crystals in distilled water to make 500 ml. of total solution. PROCEDURE
A. Solution of Sample and Separation of Columbium, Tungsten, and Other Acid-Insoluble Constituents. Weigh a 2.5-gram sample of the alloy into a 600-ml. beaker, if the columbium content is under 1.5ycand the tungsten content is under 2.07& (Should the columbium or tungsten content of the metal be over 1.5% or 2.0%, respectively, reduce the sample size accordingly.) Dissolve the sample with 50 ml. of a mixture of 1 volume of hydrochloric acid (38%), 1 volume of nitric acid (70%), and 2 volumes of distilled water. Carry along a reagent blank treated exactly like the sample in this and succeeding operations. Add 35 ml. of perchloric acid (71%) and heat until the perchloric acid begins to reflux. Cover and heat so that the perchloric acid refluxes 20 to 30 minutes. Cool, dissolve with 50 ml. of distilled water, add 50 ml. of saturated sulfurous acid and a small quantity of paper pulp, and dilute to 300 ml. with distilled Kater. Stir and boil gent1 10 to 15 minutes. Add 10 ml. of cinchonine solution, stir, and digest on the steam bath for 1 to 2 hours. Remove from the steam bath and let stand 24 hours. Filter through a KO.40 Whatman filter paper, washing with warm cinchonine wash. Discard the filtrate. B. Solution of Columbium and Tungsten in Residue. Ignite the precipitate in a platinum dish a t 600" C. To remove silica, add 3 drops of sulfuric acid (1 to 1) and 5 ml. of hydrofluoric acid, evaporate, and reignite at 600' C. for 10 minutes. Fuse with 5 rams of sodium bisulfate (fused), cool, add 4 ml. of sulfuric acid 9793, heat to fumes, then cool. C. Removal of Molybdenum. Pour the cooled solution obtained above into 40 ml. of tartaric acid solution (lo%), rinsing the dish with an additional 10 ml. of tartaric acid solution. Stir to effect solution and cool. Add 6 ml. of ammonium hydroxide (297,), dilute to 100 ml. with distilled water and boil for 1minute. Pass in hydrogen sulfide for 30 minutes. Add 100 ml. of boiling distilled water and pass in hydrogen sulfide for 5 minutes more. Add a little paper pulp and digest on the steam bath for 1 hour, keeping the solution covered. Filter through a No. 40 Whatman filter paper into a 1-liter tall-form beaker. Wash with sulfuric acid (1 to 99) saturated with hydrogen sulfide. Discard the precipitate. D. Destruction of Tartaric Acid and Preparation of Master Sulfuric Acid Solution. Evaporate the filtrate obtained in Section C to approximately 50 ml., and add 150 ml. of sulfuric acid (97%) and 30 ml. of nitric acid (70%). Stir well. Using moderate heat, evaporate until sulfuric acid fumes appear or the tartaric acid just begins to char. Cool, add 30 ml. of nitric acid (70'%), and evaporate again as above. Cool and add 15 ml. of perchloric acid (71%). Rinse down spray with distilled water. Evaporate until fumes of sulfuric acid appear and continue the evaporation with continuous strong fuming (250' C. or higher) until a volume of 128 ml. is reached. Cover with watch glass. 411ow to cool a t
f
1loo
ANALYTICAL CHEMISTRY
The columbium color develops fully after 10 minutes and once developed is Comstable up t o 1 hour. Temperature variaposite N.B.S. N.B.S. N.B.S. N.B.S. N.B.S. Columbium Columbium Tungsten Tungsten Standard lOla 50s 123a 153 116a Present Found Present Found tions (10' to 30" C.) do not affect the Grama Gram Grams Grams Gram Me. MU. Me. .!XU. intensity of the developed color. Con2.50 ... ... ... 18.8 19.2 2.8 2.8 O.'O$l 0.67 1.77 ... trary to the observations of Thanheiser ... 11.8 12.2 5.0 5.0 0.120 1.33 ... 1.05 ... 10.0 10.2 23.3 23.3 (17), who stated that tungsten does not 2.00 0,180 0.32 ... ... 15.0 15.2 35.0 35.0 ... 2.67 . . . 0.240 ... 20.0 20.2 47.0 46.8 produce any color with hydrogen per0.081 3.33 ... ... ... 25.0 14.8 24.5 14.8 4.00 0.120 ... ... ... 30.0 30.0 26.7 26.3 oxide in concentrated sulfuric acid, it 0.180 4.67 ... ... ... 38.0 34.8 38.0 35.0 ... 2.50 2.50 ... 0.20 n a s found that tungsten produces a 18.8 41.6 18.6 42.3 Nominal composition of standard samples used: ,light yellow color, which is l / 6 0 as inN.B.S. 101s. 18.33% Cr, 8 . 9 9 % S i tense as that of an equal concentration N.B.S. 50a. 3 52% Cr, 0.97% V 18.25% W N.B.S. 123a. 0:12% Mo O.O37%'V 0.75% C b 0.027, Ta, 0.11% W of columbium. A small correction is N.B.S. 153. 4.14% Cr,'8.36% Mo,' 2 . 0 3 % V. 8.43% Co, 1 . 5 8 % W N.B.S. 1168. 0.33% \ , 3.25% Al, 25.08% Ti therefore applied in the final calculaWhere weight of composite standard was over 2.5 grams (weight recommended in procedure), quantion of the columbium content of the tities of reagents specified in Section A of procediire were increased proportionately. sample. Up to 19 mg. of columbium ___._ ~ . ~ _ in 100 ml. of the master solution may be determined by this method. room temperature foi 0.5 hour and then transfer to tt dry 200-1111. Titanium also produces a yellow color with hydrogen peroxide volumetric flask, rinsing the beaker with sulfuric acid (97%). in concentrated sulfuric acid (8). Where more than 0.10% of tiDjlute to exactly 200 ml. with sulfuric acid (97%), stopper, and tanium is present in the sample, a fraction of it will be precipitated nux. This solution is hereafter referred to as the master solution. with the columbium and tungsten in the initial separation (IO) E. Colorimetric Estimation of Columbium. Transfer 100 ml. and will interfere in the colorimetric estimation of columbium. of the master solution to a dry 100-ml. volumetric flask, add 0.10 The intensity of the titanium color with hydrogen peroxide in ml. of 30% C.P. hydrogen peroxide, and mix well. Let stand 10 concentrated sulfuric acid was found to increase with the concenminutes a t room temperature. Using a 420-mp filter, compare the color intensity of the test solution against a portion of the same tration of hydrogen peroxide. I t was, therefore, advantageous master solution, containing no hydrogen peroxide. Find the to use as small a quantity of hydrogen peroxide as practicable columbium content by reference to a graph prepared from similarly which would a t the same time fully develop the columbium color. processed National Bureau of Standards steels and by application The most suitable volume of 30% hydrogen peroxide was found of corrections for the interference due to tungsten and titanium. To correct for the interference of tungsten deduct 0.43 mg. of to be 0.10 ml. Here the titanium color is 1/11 as intense as that columbium for each 25 mg. of tungsten in the sample. of an equal concentration of columbium. Inasmuch as the inTo correct for the interference of titanium deduct 1.38 mg. of tensity of the titanium color with hydrogen peroxide in concencolumbium for each 10 mg. of titanium present in the 100-ml. trated sulfuric acid increases also with the amount of water presaliquot for columbium. The titanium present is determined as follolvs: ent (@, i t is imperative that the dehydration of sulfuric acid be Dilute 10 ml. of the master solution to 100 ml. with distilled accomplished as effectively as possible by strong fuming (250" C. water, add 0.5 ml. of 30% C.P. hydrogen peroxide, and mix. Comor above). In determining the titanium content of the master pare the test solution of the sample against the reagent blank solution for the purpose of applying a correction to the columbium solution in the photoelectric colorimeter using a 420-mp filter. Find the weight of titanium in a 100-ml. aliquot of the master content (see Section E), the solution is diluted 10 times with solution by reference to a graph based upon known titanium soluwater. Hydrogen peroxide is then added and the titanium is tions. determined colorimetrically. I n the concentrations employed F. Colorimetric Estimation of Tungsten. Transfer 5 ml. of columbium and tungsten do not produce a color ( 9 ) , nor do they the master solution to a dry 100-ml. long-necked volumetric flask precipitate. which is used to minimize evaporation losses. Add exactly 20 ml. In the colorimetric determination of tungsten, it was found that of sulfuric acid (1 to 3) and then exactly 10 ml. of stannous chlothe color developed fully within 15 minutes a t 15' C. and reride reagent. Cover with a small watch glass and boil gently for 1 mained stable a t this temperature for 2 hours. A t higher temminute. Cool in air 2 minutes and then chill to 13" to 17" C., keeping the flask stoppered. Add exactly 10 ml. of potassium peratures, however, the maximum color was not developed and thiocyanate reagent and swirl well. Let stand a t the above the yellow color faded slowly, once developed. Columbium and temperature for 15 minutes. Without further dilution, compare titanium do not interfere. Up to 25 mg. of tungsten in 100 ml. the test solution of the sample against the reagent blank in the photoelectric colorimeter, using a 420-mp filter. Do not allow the of the master solution may be determined by this method. temperature of the solution in the colorimeter cell to rise above Molybdenum is retained to a large extent with the columbium 20" C. Obtain the per cent of tungsten from a graph based upon and tungsten in the initial separation (9) and would interfere qimilarly processed National Bureau of Standard steels. in the determinations of both columbium ( 1 7 ) and tungsten (6, 1 4 , if provision were not made for its removal. DISCUSSION Because some tungsten may accompany the molybdenum in hlellor ( 1 1 ) has shown that columbic oxide is soluble in conthe hydrogen sulfide separation previously described, the tungcentrated sulfuric acid. Noyes ( 1 8 ) described the solubility of sten may be recovered by a reprecipitation of the molybdenum tungstic oxide in concentrated sulfuric acid. Accordingly, in the sulfide, where higher accuracy is desired. proposed procedure the perchloric acid-insoluble compounds of Iron, manganese, phosphorus, chromium, nickel, cobalt, and columbium and tungsten are dissolved by means of sulfuric acid. vanadium are not retained in the initial separation in quantities In the colorimetric determination of columbium, all traces of that would interfere R ith the colorimetric estimation of columuitric acid must be absent; if present, it will cause a rapid bleachbium or tungsten. Tantalum and zirconium, although precipiing of the percolumbic acid color. The nitric acid is effectively tated in the initial separation, do not interfere in the determinaremoved by fuming the sulfuric acid solution in the presence of tion of either columbium or tungsten (8, 17, 18). perchloric acid. The above-described method of analysis is limited to highI t was found that 0.1 ml. of 30% hydrogen peroxide is sufficient temperature alloys containing up to 6% of columbium and tungto develop fully the color of 30 mg. of columbium in 100 ml. of sten, Various Sational Bureau of Standards samples and synconcentrated sulfuric acid. A larger quantity of hydrogen perthetic mixtures of these samples were analyzed by this method oxide would increase the titanium interference as described helow. (Table T). Table I.
Accuracy of Proposed Procedure
~~
.
1101
V O L U M E 21, N O . 9, S E P T E M B E R 1 9 4 9 ACKNOWLEDGMENT
Tlie authors aish to thank W. L. Miller, C. b. Thompson, George Nonvita, and S. H. Davang for their interest arid suggestions. LITERATURE CITED
Am. SOC. Testing Materials, Philadelphia. “A.S.T.M. Methods of Chemical Analysis of Metals,” pp. 88, 79, 1946. Feigl, F., and Krumhole, P., Angew. Chenz., 45, 674-5 (1932). Fer’yanchich, F. A., Zavodsitaya Lab., 3, 301-3 (1934). Ibid., 6, 289-92 (1937). Gentry, C. H. R., and Sherrington, L. E., Analyst, 73, 57-67 (1948). Grimaldi, F. S., and North, V., INU.ENG.CHEM.,ANAL.ED.,15, 652-4 (1943).
Hillebrand, W. F., and Lundell, G. E. F., “Applied Inorganic Analysis,” pp. 110, 476, New York, John Wiley & Sons, 1929. Klinger, P., and Koch, W., Arch. Eisenhilttenw., 13, 127-34 (1939).
Lundell, G. E. F., and Hoffman, J. I., “Outlines of Methods of Chemical Analysis,” pp. 4 7 , 5 1 , 171, New York, John Wiley & Sons. 1938.
Lundell, G. E. F., Hoffrnm, J . l., and Bright. H.A,, “Chemical Analysis of Iron and Steel,” p. 363, New York, John Wiley & Sons, 1931.
Mellor, J. W., “Comprehensive Treatise on Inorganic and Theoretical Chemistry.” Vol. IX, p. 850, London, Longmsns, Green and Co., 1929. ru’oyes, A . A., and Bray, W. C., “Qualitative Analysis for the Rare Elements,” p. 329, New York, Macmillan Go., 1927. Poluektov, N. S., Zavodsitaya Lab.. 10, 93-3 (1941). Popov, E(. A , , a n d Dorokhova, H. W., Ibid., 9, 315-17 (1940). Sxndell, E. B., I S D . ENG.CHEY.,A N A L . ED.,15, 652-4 (1943). Shalrov, A. S., Za~odskayaLab., 10, 470-3 (1941). Thanheiser, G., Mitt fi‘aiser-Tvilhelm-Inst. Eisenforsch. Dusseld o r f , 22, 255-65 (1940).
Tschernichnw, J. A., and Karajawskaja. M. P., Z. anal. Chem., 98,97 (1934).
U. S. Stcel Corp. Chemists, “Sampling and Analysis of Carbon and Alloy Steels,” p. 169, New York, Reinhold Publishing Corp., 1938. Voznesenskii, A. T., Zavodskaya Lab., 9, No. 1, 25-8 (1940). RECEIVED December 10, 1948. The opinions are those of the authors and are not to be construed as reflecting the o5cial views of the Navy Department, through whose permission t h k article is published.
Penetration of Sintered Metals by Solutions of Surface-Active Agents A. J. FINKS AND N. J. PETIT0 Material Laboratory, New York Naval Shipyard, Brooklyn 1 , N. Y
A method was devised to give an indication of the comparative wetting and penetrating qualities of surface-active agents. A definite volume (30 ml.) of surface-active agent solution is added to the most porous of a series of five stainless steel filtering crucibles with porous, sintered, stainless steel Hter elements of varying porosities. A record is made of the time in seconds required to deliver the first drop and the first milliliter of solution. Based on the time for delivery under each category, a rating is given, and the comparative wetting and penetration of each surface-active agent studied are evaluated. The same method could be applied for copper, bronze, medium steel, glass, canvas, cloth, and other textile materials. This technique could also be used in research on metal cleaning or lubrication problems.
0NE
deternhiiig [he time reqnircd to sink a standard weighkd cotton skein to the t ~ ~ ~ t t uofn i a, solution contained in a standard cylinder. illthough tllis is satisfactor). for evaluating Fetting power and penetration in the textile industry,it is not applicable to metal surfaces. Therefore, a test Table I. Seepage Data on Wetting Power and Penetration method was devised, as part of an investigation of materials Order of ConcentrhEeectiveness 8~~~~l for ~ $ - ~surface ~ ~ i for ~ ~the detection of leaks in Surfacetion, % aa8Active b y Weight. Seepage Seepage Seepage Seepage Seepage Power and Tension pipe lines, for evaluating pen* \ Agents Fresh Water Value Rating Value Rating Rating Penetration Data“ tration and wetting properties 1 2s.s Sample A 0.10 e: (1) 178 (2) (3) (1) 2 Sample B 0.20 31 .ti of surface-active agents on 169 (1) (3) (2) 100 ( 2 ) 19R 3 Sample C 0.20 106 (3) 31.1 (6) (3, metals. This procedure used 4 Sample D 0.20 145 (4) 215 (3) (8) (4) \4) 43.2 5 Sample E 0.2@ 158 (5) 238 (5) (10) (5) 31., stainless steel filtering crucibles 6 Sample F 0.20 210 (6) 287 (6) (12) 28.5 7 Sainple G 0.10 301 (7) 404 (7) (14) !:( 43 1 with porous, sintered, stainless 8 Fresh water 100.00 365 (8) 425 (8) (16) 75.0 steel filter elements of varying Dynes per ern. a t 25‘ * l o C. porosities, and recorded the . . ~ ~ ~ ~ _ ~. _ -~ time required to deliver defi-
of the most convenient and useful methods for determining perletration and m-etting power of surface-active agents is that of Draves and Clarkson ( I ) , commonly referred to as the Draves sinking time test. This method consists of
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