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By T. E. Eagan, W. R. McCrackin

IN dealing with segregation in babbitt, and its effect on the final cast structure, which is a bearing, it is obviously impossible to cover all of the compositions manufactured. Each composition, of course, will exhibit certain specific types of segregation. However, as examples,, two compositions of babbitt are presented: one a tin-base of well-known analysis and the other a lead-base, which in the past few years has found wide usage. Bearings usually are cast either statically or centrifugally; therefore the effect of these two methods on segregation is presented. EXPERIMENTAL PROCEDURE A slab of babbitt 1/2 in. thick by 5 in. wide and 17 in. long was cast, using a book mold with the long edge vertical. An A.S.T.M. grade 2 babbitt was used (3.5 per cent copper, 7.5 per cent antimony, remainder tin), to which 0.10 per cent tellurium had been added. Unfortunately, no metal without tellurium was available. The mold to hold the babbitt was heated to approximately 300°F., the temperature being judged by the babbitter. The pouring temperature of the babbitt was 875°F. (470°C.). One slab was made by allowing the babbitt to cool without stirring. The other slab was stirred during the entire cooling cycle. This stirring consisted of a vigorous churning or puddling into the mold until complete solidification had taken place. Three samples were removed from these slabs. One was taken at the extreme bottom, another half way to the top, and another at the extreme top, all at the center of the width. Chemical, macroscopic and microscopic examination was made of all samples. Table I shows the chemical analyses obtained at the described positions [ ] in the slab. The analyses show no serious amount of gravity segregation. Microscopic examination from edge to edge of the slab showed little change in structure. From top to bottom there was a progressive coarsening of the grain size in the stirred slab but little change in the slab that was not stirred (Fig. I). No definite exhibit of segregation could be detected. In line with our experimental study on the tin-base babbitts, we cast an almost duplicate slab using A.S.T.M. Alloy No. 15, containing 0.9 to 1.25 per cent tin, 14.75 to 15.5. per cent antimony, 0.80 to 1.25 per cent arsenic and 0.4 per cent copper. The slab was 16 in. long and 3/8 in. thick, cast with the long side vertical. One slab was allowed to cool normally and the other was stirred continually during cooling. The pouring temperature of the babbitt was

Jan 1, 1944

By H. O. Hoffman, C. D. Demond

There are two methods of determining the fusibility or refractoriness of fire-clays, the theoretical and the experimental. In the former, conclusions are drawn from the chemical composition; in the latter, from the changes which the clay undergoes when subjeoted to intense heat. It is well to use both methods, beginning with the actual heat-test and explaining the results obtained from this by the help of the chemical analysis. In discussing the subject, however, it is better to reverse this order. I. The Theoretical Method.* Leaving out the hygroscopic and combined waters and any organic matter, as not directly affecting the fire-resisting property, the refractory constituents of fire-clay are alumina and silica, and the fluxing constituents magnesia, lime, soda, potash and ferric oxide. According to Bischof,† alumina is the least fusible component, and silica follows close upon it. If, however, a mixture of the two be heated, it will be found that its melting-point is much lower than that of alumina, as a silicate will then have been formed. The way in which silica affects the refractoriness of alumina has been strikingly presented by Seger 1 in a diagram reproduced in Fig. 1. The abscissæ represent the melting-points of Seger cones Nos. 26 to 36 (see p. 55); the ordinates, the relative amounts of alumina and

Jan 1, 1895

The high-grade orebody at Miami was mined successively by top-slicing, shrinkage, stoping and under caving. The method described in this paper was developed to enable the low-grade orebody (36,000,000 tons assaying 1.06 per cent copper) to be mined at a low cost without further dilution of the grade. The method is clearly described and illustrated by drawings and photographs, and the original paper should be consulted as it is impracticable to abstract it, beyond noting that the mining cost is just under 40 cents per ton and the average grade of ore now being produced yields less copper than the mill tailing of 1915, the tons mined per day having increased from 4000 to 18,000 in the same period. Vertical and Incline Shaft Sinking at North Star Mine By Arthur B. Foote, Grass Valley, Calif. (Tech. Pub. No. 324: Class A. Metal Mining, No. 36) THE main shaft of the North Star mine is an inclined one following the main vein at an average dip of 26 deg., a vertical shaft intersects it at the 4000-ft. (incline) level, the incline continuing to the 6300-ft. level. At this point the vein was found to give out and a new vein, called the No. 1, was found to dip in exactly the opposite direction.

Jan 1, 1930

By Bruce E. Grant, Thomas Jancic, Lawrence G. Dykers, Frank Buchella

Principal factors influencing equipment selection can be grouped into five basic categories: tonnage requirements, ore and waste; topography and property line considerations; ore control requirements; physical characteristics of ore and waste; and climatic considerations. Loading, transporting and ground preparation equipment are largely determined by tonnage requirements. Large size equipment is appropriate for a production of about six million tpm, medium size for three million tons and small size for one million tons or less.

Jan 12, 1973

By Y. C. Liu, G. A. Alers

The anisotropy of Young's modules has been measured in a series of Cu-Zn alloys containing from 1 to 28 wt pct Zn and cold-rolled to 97.5 pct reduction in thickness. These modulus data show a transition in texture as a function of zinc content. In alloys containing 3 pct Zn or less, the texture is essentially that of copper. A transition is clearly seen to develop in 5 and 8 pct Zn alloys, and to have been completed in a 12 pct Zn alloy. Increasing the proportion of zinc to 28 pct does not produce any further changes in texture. The ease and clarity with which this texture transition can be seen in the modulus data is in great contrast with the inccertainty in the visual detertiination of the range of texture transition from a series of pole figures. It is also shown that the rolling texture of the high zinc content alloys cannot be a one-COIIIponenl texture, characterized by the (110)(112) ideal orientations, as usually assumed. A second, quite important component must also be present. Furthermore, the present data are inconsistent with matrix orientations on which the "oriented growth" hypothesis of the Formation of recrystallization textures is based. THE rolling textures of binary fcc alloy systems have generally been considered to lie between two terminal textures. One of these terminal textures is the copper type and the other is the 70:30 brass type. Alloys of intermediate solute content exhibit a texture which is said to be a transition between the two terminal textures. On the basis of efforts to correlate rolling and recrystallization textures, two concepts have been advanced in the literature on the nature of these transition textures. One school1 suggests that the addition of alloying elements, e.g., zinc, causes a gradual rotation about one of the (111) poles from the (358)( 523) ideal orientation of the copper-type rolling texture to the terminal {1 10)( 112) ideal orientation used to describe the rolling texture of 70:30 brass. This concept is depicted in Fig. 1 with the angle of rotation corresponding approximately to the zinc content and is designated here as the "rotational concept", since the ideal orientation of the transition textures varies continuously with alloy content. The other concept,' the "mixture concept", suggests that the copper-type rolling texture is a two-component texture. {358) (523) and {110)(112). The addition of alloying elements affects only quantitatively the relative amounts of these two components—a decrease in the amount of material in the {385}(523) orientation and an increase of that in the {110)(112) orientation with increasing solute content. An experimental distinction between these two concepts is essential to a better understanding of both the mechanism of formation of rolling textures and the subsequent formation of recrystailization textures in fcc metals. Because of the lack of resolution inherent in pole figures, it has not been possible to differentiate between the two concepts on the basis of this data. Both concepts, in fact, make use of the same set of pole figures but interpret them in a manner acco-rding to the view held.'" Experimental results obtained from inverse pole figures or selected-area electron diffraction3j4 simply -yield more refined pole figures but do not eliminate the ambiguity of interpretation. Quantitative measurement of an entirely different, orientation-dependent property must thus be considered

Jan 1, 1967

By Thomas T. Read

Jan 1, 1913

By AUDLEY H. STOW

I. INTRODUCTION. THE general drift of the discussion as to the relative merits of pressure- and exhaust-fans has resulted, if we may judge from the prevailing practice, largely in favor of the latter. The subject has been hitherto treated, however, with special reference to highly gaseous mines, the effect of the form of ventilation upon dust-explosions having been too little considered. Even in mines containing practically no gas, dust-explosions may occur; and if, as I believe, pressure-fans are to be preferred for their effect upon dust, it may be worth while to reopen the debate, and to challenge the advisability of exhaust-ventilation under certain conditions. There are several forms of colliery-ventilation, which may be described as follows: Plain or simple pressure-ventilation, in which the fan acts as a pressure-fan, and the movement of coal is unobstructed at the surface by doors or equivalent devices in drifts or shafts, the traveling and haulage thus being in the return-current. Plain exhaust-ventilation, in which the fan acts as an exhaust-fan, the movement of coal being likewise unobstructed at the surface, and the traveling and haulage being in the intake. Obstructed pressure-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the intake. Obstructed exhaust-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the return. The apparent advantages in running a fan "pressure" during working-hours, and " exhaust" between shifts, seem to justify the recognition of this combination as a standard form of ven-

Feb 1, 1909

By C. E. Abbott

The Birmingham district, Alabama, is distinctive in the proximity to one another of its deposits of iron ore, coal and flux. These three basic requisites for the making of iron and steel are found within a radius of 10 miles. Both dolomite and limestone are produced, the former for blast-furnace flux and the latter for basic open-hearth operations. The Tennessee Coal, Iron and Railroad Co., a subsidiary of the United States Steel Corporation, operates a limestone mine at Muscoda, near Bessemer, 12 miles southwest of Birmingham, served by its own railroad transportation system. The mine has a capacity of 130 tons per hour. Average analyses of a recent month's production arc as follows: Fe²zO³ SiO² Al²O³ CaCO³ MgCO³ Lump, percent............................. 0.51 0.22 98.63 0.14 Crushed and washed, per cent,................ 0.70 0.26 98.36 0.18 Lump stone, 2 1/2 to 755 in., is used in open-hearth operations at Fairfield Steel Works. Fine crushed and washed stone, 1% to 0.063 in., is calcined at the lime-burning plant and used for lime charges at the Ensley open hearths. Geology The district's deposits of hematite ore occur in the Clinton formation, and the limestone beds mined are stratigraphically 330 ft. above the ore beds worked. A cross section on the center line of the mine is shown in Fig. 1. This limestone formation, 130 ft. thick, is in the Warsaw horizon of the Lower Mississippian. It lies above 100 ft. of Fort Payne chert, which is immediately above the Clinton formation, and is composcd of layers of chert and cherty limestone, approximately 50 per cent of the material being pure chert. The chert is extremely hard, and the cost of driving raises through it is very high. Both iron ore and limestone deposits lie on the southwest limb of the Jones Valley anticline, the formations dipping from 15' to 32' to the southeast. The iron-ore seam outcrops along the crest of Red Mountain, a ridge with northeast-southwest trend rising 200 to 300 ft. above Jones and Shades valleys at the

Jan 1, 1938

By C. E. Abbott

The Birmingham district, Alabama, is distinctive in the proximity to one another of its deposits of iron ore, coal and flux. These three basic requisites for the making of iron and steel are found within a radius of 10 miles. Both dolomite and limestone are produced, the former for blast-furnace flux and the latter for basic open-hearth operations. The Tennessee Coal, Iron and Railroad Co., a subsidiary of the United States Steel Corporation, operates a limestone mine at Muscoda, near Bessemer, 12 miles southwest of Birmingham, served by its own railroad transportation system. The mine has a capacity of 130 tons per hour. Average analyses of a recent month's production arc as follows: Fe²zO³ SiO² Al²O³ CaCO³ MgCO³ Lump, percent............................. 0.51 0.22 98.63 0.14 Crushed and washed, per cent,................ 0.70 0.26 98.36 0.18 Lump stone, 2 1/2 to 755 in., is used in open-hearth operations at Fairfield Steel Works. Fine crushed and washed stone, 1% to 0.063 in., is calcined at the lime-burning plant and used for lime charges at the Ensley open hearths. Geology The district's deposits of hematite ore occur in the Clinton formation, and the limestone beds mined are stratigraphically 330 ft. above the ore beds worked. A cross section on the center line of the mine is shown in Fig. 1. This limestone formation, 130 ft. thick, is in the Warsaw horizon of the Lower Mississippian. It lies above 100 ft. of Fort Payne chert, which is immediately above the Clinton formation, and is composcd of layers of chert and cherty limestone, approximately 50 per cent of the material being pure chert. The chert is extremely hard, and the cost of driving raises through it is very high. Both iron ore and limestone deposits lie on the southwest limb of the Jones Valley anticline, the formations dipping from 15' to 32' to the southeast. The iron-ore seam outcrops along the crest of Red Mountain, a ridge with northeast-southwest trend rising 200 to 300 ft. above Jones and Shades valleys at the

Jan 1, 1938

US 4,132,635 -In the froth flotation beneficiation of low- grade siliceous iron oxide ore, an aqueous pulp of undeslimed ore is conditioned first with a reagent formed by incorporating a water-soluble polyvalent metal salt into an aqueous solution of sodium silicate and then with oleic acid or other anionic collector and optionally pine 011 or other frother. The conditioned pulp is subjected to flotation to concentrate Iron oxide values in the froth D. C. Yang, assigned to Michigan Technological University Jan 2, 1979 7 pp (209-1 66) Filed 1-1 3-77 (759,094) Drawing below.) [ ] US 4,133,038-In the froth flotation beneficiation of copper sulfide ore or other ores, an aqueous suspension of a mineral sample of uniform grain size and composition is conditioned with a strongly adsorbable collector in an amount which is a fraction of the amount sufficient to create a monomolecular layer on the mineral grains, and the conditioning continued until the entire amount of collector is adsorbed The conditioned pulp is subjected to flotation, the floated particles separated at timed intervals, and the flotation rate coefficient determined. By varying the degree of adsorption in repeated treatments, the dependence of the flotation rate coefficient on the degree of adsorption may be determined A Nieml Jan 2, 1979 10 pp (364-502) Filed 12-7-77 (858,353) Priority Finland, 5-26-75 (75/1,525) Same: British 1,533,723, dated Nov 29, 1978 Same Canadian 1,065,066, dated Oct 23, 1979 US 4,133,746System and method for maintaining substantially steady state conditions in the froth flotation beneficiation of copper ore, molybdenum ore, or other metal ores The mass flow of flotation concentrate from the cell is monitored continuously, and the rate of admission of aeration air into the pulp in the cell is varied inversely with respect to variations in the mass flow control of rougher flotation cells is accomplished with a single valve G W Dopson, assigned to Magma Copper Co Jan 9, 1979 6 pp (209-1) Filed 11- 23-76 (744,306

Jan 1, 1980

By J. C. Reed

CINNABAR was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigel1 by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County-across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done con-siderable exploration work and has retorted the high-grade ore so .obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district.

Jan 1, 1935

By John Fritz

MEMBERS of the American engineering societies who were in London and Paris during the last days of. June and early July were present at many interesting gatherings. The official delegates of the Founder societies were the specially honored guests of the foreign engineering societies, but other American engineers took part in the meetings. The members of the delegation were: Arthur S. Dwight, Charles F. Rand, William Kelly, representing A. I. M. E.; Ambrose Swasey (general chairman of deputation), Ira N. Hollis, Jesse M. Smith, representing A. S. M. E.; F. B. Jewett, A. E. Kennelly, G. O. Squier, representing A. I. E. E.; Charles T. Main, Robert A. Cummings, John R. Freeman, D. C. Henny, representing A. S. C. E.

Jan 1, 1921

Falconbridge Nickel, the one-time subsidiary that grew up to swallow its own parent, Ventures Limited, in 1962, is not about to be left behind by rising nickel consumption. At a cost of several hundred million dollars, this Canadian firm has undertaken a series of new projects that will not only ensure its present share of the market, but also lead it into new areas of the nickel business. Although Falconbridge Nickel Mines Ltd. was not formed until 1928, it actually had its start in 1917- 18 with the discovery of a large, good grade nickel- copper deposit in Falconbridge, near Sudbury, Ontario. However, due to several factors, financing could not be obtained and the orebody lay fallow. It was not until 1928, when the Thayer Lindsley interests bought the property from the original owner, that it was developed.

Jan 10, 1968

By W. G. Bearden, G. C. Howard, J. W. Spurlock

An investigation of the factors af-fec.ting the inter-zonal flow of fluids in the casing-wellbore annrc1rt.s of an oil or gas ivell is presented Laborntory tests revealed that failure of the caring-cement bond allows communi-cation of fluid at pressure differentials near 1.000 psi. Perforating with a 11011011: carrier gun does not shatter or crack the cement sufficiently to allow communication through these cracks and does not seriously affect the casing-cement bond failure pressure. The pressure to cause communication at the casing-cement bond can he increared to 3,000 psi by. limiting pipe deformation during cementing and subsequent operations. Communication can be prevented, however. up to pressures sufficient to cause the cement to fail or the casing to col-lapse, by attaching to the casing a seal ring of deformable ruhber molded between two steel flanges. When installed, one flange is attached rigidlv to the casing to serve as back-up for the gasket While tile other flange is movable. To date, these gasket seal rings have been field-tested in 27 Wells. Althotrgh communication has been noted in two wells, inter-zonal flow has been prevented in other wells in the same area by installing more seal rings between the communicaring zones. INTRODUCTION The inter-zonal flow of fluids behind casing cemented in oil wells during normal production or stimulation operations is a major operating problem. If it cccurs during production operations. it can seriously limit the pressure to which a reservoir may be depleted without harmful invasion of unwanted fluids. If it occurs during stimulation operations, it may preclude the possibility of stimulating the desired zone. This communication can be caused by failure of the bond between the casing and cement, failure of the bond between the cement and formation, or failure of the cement itself. This paper presents the results of an investigation of factors affecting com-munication at the casing-cement bond and methods which aid in preventing it. LABORATORY INVESTIGATIONS The laboratory tests performed in this study were divided into three phases. The first phase consisted of tests to determine if perforating would shatter and crack the cement sheath so severely that communication would occur through the cement itself. The second phase consisted of tests to determine more precisely the cause for the casing-cement bond failure. The third phase consisted of tests to evaluate the effectiveness of various de-formable seals attached to the casing in preventing communication. EFFECT OF PERFORATING, The effect of perforating was invest~gated in tests performed with apparatus shown on Fig. 1. Cement was poured into the annulur space hetween 5%-in. casing and 8%-in. casing and allowed to cure for 72 hours. The apparatus was then perforated with a hollow carrier gun containing eight duPont 26-A shaped charges. Bull plugs were placed over the perforations in the 8 5/8-in. casing and hydraulic pressure was applied inside the 5 1/2i-in. casing. The pressure to cause fluid communication past the cement sheath was observed and termed the "bond failure pressure". Several different cement compositions were included in these tests, the results of which are shown in Table 1. In Tests 1 through 4 of Table 1, bond failure occurred at- the inter- .

Jan 1, 1966

By Charles V. Jenkins

The structure of steel, when rendered coarse by over-heating, is made fine by re-heating to a certain temperature, the determination of which has received much attention from eminent metallurgical authorities. Among these, I may particularly mention Prof. D. Tschernoff' [Chernoff], who, about thirty years ago, studied this question in connection with his investigations on the structure of steel in genera1. † Some years later, Mr. J. A. Brinell took up the inquiry, and arrived at many important conclusions, stated in his well-known rules on the treatment of steel. ‡ These two gentlemen, however, based their reasoning chiefly upon the aspect of fractures—a method which, though it affords valuable information, does not readily reveal the different steps by which a change in structure takes place. For further light on the subject, we owe much to more recent microscopic investigations, which have made us better acquainted with the internal structure of metals. Such an investigation, closely connected with the present subject, and made by Mr. John E. Stead a few years ago, was first published in 1898.6

Jan 1, 1903

Meeting of June 26, 1914.-The President was authorized to appoint Advisory Committees to co operate with the United States Bureau of Mines. The President announced the appointment of Edward H. Benjamin and W. C. Ralston as additional members of the Committee on Arrangements for the San Francisco meeting, 1915. H. T. Van Ells and Judd Stewart were appointed to represent the Institute on a joint committee of several technical societies to consider the standardization of graphical methods for the presentation of statistics. The President announced the appointment of H. Foster Bain to succeed Edward H. Benjamin, resigned, on the Committee of Management of the International Engineering Congress, 1915. The Secretary was authorized to issue a new circular advertising the sale of back Transactions and to sell back Transactions, bound in cloth, at a price of $35 for 46 volumes, provided sufficient orders were received to warrant the special binding. The sum of $177.50 was contributed to the San Francisco Local Section. Upon recommendation of the Committee on Membership, 70 Members, 4 Associate Members and 7 Junior Members were elected to their respective classes; there was also one change of status from Junior Member to Member.

Jan 8, 1914

By AIME AIME

Gentlemen, we have ten questions on our list and a number of us here probably have other questions to ask. Therefore, we arc going to allocate the time to these different questions so that we will try to be finished by 4:30; from then until 5 o'clock, if any of you have any questions on subjects not related, you will be free to ask them. Mr. Morton and I have changed the order of the questions. Instead of what is now first, we have put No. 3 first, progress on basic-roof construction, inasmuch as we feel that it is quite important. At this time, H. S. Robertson, of Harbison-Walker, is going to give you a short talk, with slides, on what has been done to date on this subject.

Jan 1, 1940

By Oscar A. Glaeser

INDUSTRIAL relations in the United States Smelting Refining and Mining Company's Western operations covers the field of personnel and labor relations, and the principal aims are to render service to the employes of the Company and to its operating departments. Accident prevention Safety is a primary function. A safety engineer is employed at each operation. The wholehearted support of Company officials, staff, and the working force has been most successful in preventing accidents. Constant vigilance has been combined with a policy of building safety into all operating activities whether these are in the construction of a new facility, the developmnt of a mining system, or the direction of the working force. That this policy has produced results is attested to by the fact that the accident frequency rate at the Company's major mining operations in Utah has been reduced approximately 75 per cent in the ten-year period ending Dec. 31. 1946.

Jan 1, 1948

By David B. Brooks

INTRODUCTION Resources are not; they become (Zimmermann 100) . The companion concepts of reserves and resources appear, one way or another, in almost all considerations of mineral supply. Yet, no other concepts in the economics of the mineral industries have occasioned so much confusion. Whereas everyone agrees that in general the terms refer to the amounts of material that-depending upon technology, market conditions, and institutions-will become available for production in the near or more distant future, the apparent agreement disappears when we come to more specific definitions or to application of the definitions. Some definitions emphasize the physical aspects of reserves and resources, while others emphasize the economic. Some treat reserves and resources as fixed quantities, while others regard them as continually varying. Some consider that reserve and resource estimates have validity only for individual deposits, while others insist that they can be measured with sufficient accuracy for regional or national planning. This confusion in concepts that lies at the very heart of mineral economics is both strange and not so strange. It is common in the social sciences to find concepts that have been adopted into scientific jargon from popular usage and given rather special meanings -at the same time that they continue to be widely used without such qualifications. Psychologists have the same trouble with personality and sociologists, with community. Nevertheless, an attempt must be made to straighten out the various meanings of reserves and resources, or at least to clarify the conditions under which different meanings are applicable, before much progress in analysis of mineral problems can be expected. That is the objective of this chapter. Throughout the chapter, an attempt has been made to provide enough references to guide the interested reader to the most pertinent works on the concepts under study. However, even in a review article, it is no longer feasible to provide a comprehensive set of citations; there are simply too many. In many instances the works cited will themselves include the bibliographies needed to complete a literature search; those that are particularly useful in this respect are so noted. Also, because of the limited availability of foreign periodicals, some important works -originating largely in Canada, France, the

Jan 1, 1976

By T. S. Lundy, J. I. Federer

Chemically purified Zr95and Cb95 have been used in determining self-diffusion coefficients in the bcc phase of iodide zirconium over the temperature range of 900o to 1750°C. The temperature dependence of the diffusion coefficients could not be described by the usual Arrhenius-type equation over the entire temperature range. Values of the apparent frequency factors (D0)a and activation energies (Q)A for ZR95 varied from 4.8 x 10-6 to 2.5 x 10-2 sq cm per sec and 20,700 to 46,900 cal per mole, respectively, between 900°and 1750°C. Similarly, for Cb95, values of (Do) a and (Q)A varied from about 2.4 x 10'5 to 0.25 sq cm per sec and 26,500 to 56,800 cal per mole, respectively. The data may be described in terms of the a to ß transition temperature of 1136 °K and the absolute temperature of the diffusion anneals by the following eauations: SEVERAL studies on the diffusion of Zr95 in zirconium have been reported.1"5 The values of the constants contained in the usual Arrhenius-type equation for describing the temperature dependence of the diffusion coefficient, D = Do exp [- Q/(RT)], are summarized in Table I. The reported values of Do, the frequency factor, and Q, the activation energy, are seen to vary by factors of about 60 and 1.6, respectively. Examination of the data from any one study indicated reasonable consistency of measurements. The large discrepancies of over-all results, therefore, cannot be explained on the basis of experimental scatter. One possible explanation for the differences in results could be a varying impurity content of the zirconium. Another possibility is that the radioactive daughter, Cb95, influenced the values of some of the determined diffusion coefficients. Therefore, the first of the three purposes of this study was to reconcile the large differences in diffusion results that have been obtained. Several empirical relations have been proposed to relate the diffusion coefficients in solids with physical properties, such as the absolute melting point, the heat of fusion, and the heat of sublimation.

Jan 1, 1963