The Quantitative Evaluation of Oxygen in Zirconium

Lilliendahl, W. C.; Wroughton, D. M.; Gregory, E. D.

doi:10.1149/1.2773811

Cited by 17 publications

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“…In both cases, they were concerned with solid solutions and heated wire to 1900 K to dissolve the gas in the metal. Lilliendahl (8) and co-workers used somewhat the same method in investigating additions of oxygen .to zirconium.…”

Section: Introductionmentioning

confidence: 99%

Some Effects of Heating Zirconium in Air, Oxygen, and Nitrogen

Hayes¹,

Roberson

1949

J. Electrochem. Soc.

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Zirconium metal was heated in nitrogen, oxygen, and air at temperatures ranging from 425 to 1300 C. Observations were made on the gain in weight, micro-and macrohardness, and metallographic structures. Nitrogen diffuses into zirconium at a much slower rate than oxygen. A marked increase in penetration of both gases was found near 900 C, and this is evidently associated with the allotropic transformation from' hexagonal, to cubic form. Practical limits for the heating of zirconium in air, oxygen and nitrogen are given and the possibilities of producing hard surface coatings are discussed. INTRODUCTIONThe advent of Zirconium metal in quantities sufficient for thorough studies of the properties of the metal has been reported previously by the Bureau of Mines, U. S. Department of the Interior (1, 2, 3). This metal, which is produced by the magnesium reduction of zirconium chloride, continues to be the subject of considerable research. In the production of sheet, rod, and other shapes for various test purposes, it has been found (4) that the metal work hardens rather rapidly at room temperature and in general will take only 40 to 50 per cent reduction by cold working. The obvious answer of hot working is complicated by the fact that zirconium, when heated, reacts avidly with oxygen and nitrogen. It has been known for many years that small amounts of oxygen and nitrogen, when dissolved in the metal, cause it to lose its ductility, but no systematic approach seems to have been made to determine the effects of oxygen and nitrogen on ductile zirconium, that is, the limits to which it may be heated in either gas or air without impairing its desirable physical properties.The investigation described in this paper was undertaken with the object of determining the practical limits to which Bureau of Mines zirconium could be heated in oxygen, nitrogen, or air without deleterious effects. As a secondary feature, the general nature and hardness of the surface coatings produced were studied from the standpoint of hard-surfacing materials for zirconium. The hardness of some of the films proved so interesting that attempts were made to determine their stability when reheated in air.Fast (5) annealed zirconium made by the iodide process in vacuum, air, and a gas flame. His work was largely qualitative, in that it was restricted to a few minutes. He concluded that heating 3 to 5 minutes in air at 650 C was the maximum for thin (0.012 in.-0.305 mm) sheet.

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Section: Introductionmentioning

confidence: 99%

Some Effects of Heating Zirconium in Air, Oxygen, and Nitrogen

Hayes¹,

Roberson

1949

J. Electrochem. Soc.

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“…Weigh out 1 gram of sample and 2 grams of spectrographic Per cent oxygen 36.36 (TF -BT) + 40.05 P M where P = weight of titanium dioxide, grams Zirconium. Oxygen in zirconium has been determined byvacuum fusion (35,36), isotopic dilution (20), chlorination using chlorine or hydrogen chloride (22,27) and by igniting in oxygen and observing the gain in weight (22). Because of the similarityin the metallurgical and chemical properties of the zirconiumoxygen and titanium-oxyrgen systems (8,25), the method can be readily applied to zirconium.…”

Section: Methodsmentioning

confidence: 99%

Determination of Oxygen in Titanium, Zirconium, Chromium, Vanadium, and Steels by Bromination-Carbon Reduction Method

Codell¹,

Norwitz²

1956

Anal. Chem.

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“…The oxygen remains as titanium dioxide (Ti02) and is calculated by determining the titanium colorimetrically. A correction must be made for the carbon present in the sample (6), and the chlorination reaction must be carefully controlled to prevent attack on the oxide by the chlorine with the production of gaseous oxygen (16), If molybdenum, tungsten, or vanadium is present, some oxygen may be lost as the oxychloride (7,31,41)• Instead of chlorine, dry hydrogen chloride can be used (2, 27).…”

Section: Previous Methodsmentioning

confidence: 99%

Determination of Oxygen in Titanium and Titanium Alloys

Codell¹,

Norwitz²

1955

Anal. Chem.

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1083V L = 0.02 ml. of a 0.2% solution = 0.04 mg. Substit,uting: where these are significantly greater than the 2 to 3% variation attributable to the disks themselves. 811 1As the degree of purity of the original enzyme preparation 22 4 30 0 04 ultimately determines the activity of the disks, preparations I ' = -X -X -= 3.01 micromoles/minute/mg. Table I11 summarizes the specific activities as calculated for each of the methods above together with the standard deviation to be expected for each met,hod of assay. The variability found for each method as calculated from the ratio of the standard deviations t o the mean specific activit,y is wit'hin a few per cent in every instance.STABILITY O F CHOLISEBTER.4SE DISKS UPON STOR.4GE. The stabilit,y of the disks prepared in the various media was studied by determining the activity of freshly made disks by one cr more of the methods previously described; t'hen st,oring similar diska under the conditions and for the time noted in Table IV followed by a det,ermination of their activity.Inspection of Table I T T shorn that optimal retention of initial activity i.5 achieved by storing in the cold over a desiccant. Disks decrease t o 62% of t,heir initial act,ivity in 22 days when exposed t o an atmosphere of 100% humidity a t room temperature.The effect of the stabilization inediuni is shown by a coniparison of the disks prepared in the bovine albumin n-ith those prepared in the gelatin medium and stored under identical conditions. The disks prepared in the 47, bovine albumin had lost virtually no activity in 6 months, whereas those prepared in the gelatin medium had lost one fourt,h of t,heir initial activity. DISCUSSIONThe conditions used in the four methods for measuring the cholinesterase activity of the disks differ in salt concentration, presence of protein stabilizer, substrate concentration, and period of time used in measurement,. Because these factors all affect the stability and activity of the enzyme, it is to be expected that the specific cholinesterase act,ivit)-of a given preparation, meaeured by different procedures but expressed in the same units, will vary from one method to the nest. However, the variability of 2 to 3% found for the activity of the disks by any of the procedures described here permits their use in calibrating the activity measured bjone met,hod in terms of another, provided that a given set of conditions is consistently followed. I n addition, the disks may serve to point out sources of experimental variations other than the one used in this study will yield different specific activities. Standardization of different techniques may nevertheless be achieved with any such preparation.Under the conditions specified in this report the titrimetric procedure gave the highest specific activity, followed in turn by the colorimetric, manometric, and electrometric procedures.The last named method has the advantage of requiring the fewest reagents, and permitting inany samples t o be measured with a minimum of manual operations, thus minimizing the ...

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The Quantitative Evaluation of Oxygen in Zirconium

Cited by 17 publications

References 0 publications

Some Effects of Heating Zirconium in Air, Oxygen, and Nitrogen

Some Effects of Heating Zirconium in Air, Oxygen, and Nitrogen

Determination of Oxygen in Titanium, Zirconium, Chromium, Vanadium, and Steels by Bromination-Carbon Reduction Method

Determination of Oxygen in Titanium and Titanium Alloys

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