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THOSE NOT MARKED ARE MEMBERS; MARKED THUS ?ARE ASSOCIATES. HEAVY-FACED TYPE SIGNIFIES HONORARY MEMBERSHIP JUNIOR MEMBERS ARE MARKED ' . THE FIGURES AT THE END OF THE ADDRESS INDICATE THE YEAR OF ELECTION. AARONS, J. BOYD See Honor Roll. '05 ? AARONSON, ALFRED E Pres., Tuloma Oil Co., Unity Bldg., Tulsa, Okla. '18 ABADIE, EMILE R., Min. En r Box 291, Porterville, Tulare Co., Cal. '76 ABBOTT, CLARENCE E., Gen'l Supt., Iron Mines Div., Tenn. Coal, Iron & R. R. Co., 1405 Minnesota Ave., Bessemer, Ala. '04 ABBOTT, Louis BENJAMIN, Chief Engr., Consolidation Coal Co., Elkhorn Div., Jenkins, Ky. '15 ABBOTT, ROBERT R Met. Engr., Peerless Motor Car Co., Cleveland, Ohio. '12 ABE, ASAKA Fujitagumi Taiwan Office, Taipeh, Formosa, Japan. '14 ABBY, HIROSHI Min. & Met. Engr., Mitsubishi Co., Tokyo, Japan. '17 ||ABOUCHAR, S. S., Cia. de Minerales y Metales, S. A., Minas Viejas, Villaldama, N. L., Mexico. '17 ABRAHAMS, A. I 1391 Madison Ave., New York, N. Y. '14 ?ACKER, E. O'C., Met.,128 East Washington Lane, Germantown, Philadelphia, Pa. '86 ? ACKERMAN, ERNEST R., Pres., Lawrence Portland Cement Co., Plainfield, Union Co., N. J. '15 ACOSTA, J. N., Min. Engr., Cons. Engr Hotel Brewster, San Diego, Cal. '15 ADACHI, JINZOO 11 Shiba Park, Shiba-Ku, Tokyo, Japan. '88 ADAMI, CHARLES J., Min. Engr., Gen'l Supt., St. Joseph and Doe Run Lead Companies, Bonne Terre, Mo. '12 ADAMS, ARTHUR K., Min. Geol., Andes Copper Min. Co., Casilla 230, Antofagasta, Chile. '06

Jan 1, 1923

By Hugh D. Pallister, Richard W. Smith

The Alabama flake-graphite industry has flourished only in times of war when importations of foreign graphite for crucible use have been greatly curtailed or cut off. World War I was a boom period and in 1918 some 30 plants produced 7,795,475 lb. of flake graphite. The industry languished following the war and no graphite was produced from 1929 to 1939. The Federal Bureau of Mines began investigating the Alabama graphite deposits in 1940 and worked out modern recovery methods that were applied to production during part of World War II. A prospecting program disclosed reserves of over 25 million tons of graphitic schists. In 1942 the War Production Board authorized the enlargement of the only plant then producing flake graphite and the construction of two new plants. Production of flake graphite from these three plants in 1943 is estimated at 8,100,000 lb. Increased imports from Madagascar late in 1943 shut down one of the new plants and curtailed production at the other. Alabama flake graphite has not yet been able to compete with Madagascar graphite for use in the manufacture of any but small graphite crucibles. The future of the industry must depend on meeting the higher carbon content demanded for other uses.

Jan 1, 1945

By V. D. Perry

Mineralized breccia pipes, because of their widespread occurrence and close structural relations to some of the world's great ore bodies, are objects of unusual interest for mining engineers and geologists. The literature contains many references to them, but it is questionable whether their genetic significance and economic importance have been sufficiently emphasized. The purpose here is to stress these features, relating them to the field facts, for the particular benefit of younger generations of geologists who, confronted with and sometimes confused by the growing flood of geochemical, geophysical, and other specialized research approaches, may be reassured that mappable field relations remain a foremost guide to a better understanding of ore deposits. A mineralized breccia pipe is a pre-mineral, breccia structure which has controlled the circulation and deposition of subsequently introduced mineralization. It is composed of relatively rotated angular or rounded rock fragments, set in a mineralized matrix. A pipe in plan outline may be circular, oval or approach polygonal form, with a steep to vertical axis proportionately much greater than its horizontal dimensions. The pipe is a steeply plunging, chimneylike mass of brecciated rock cemented with later minerals. Rock breaks in a variety of ways and complete fragmentation often occurs without rotation of individual pieces. A finely broken rock mass may fit into a tight jig-saw pattern, each fragment having mutually concordant boundaries with its neighbors. The result is a stockwork of innumerable reticulating cracks that, once cemented by mineralization, forms a complicated intersecting network of individually insignificant but collectively important seams and veinlets. Stockwork fracturing among its many forms takes the shape of domes of subsidence, fracture pipes, and related peripheral zones around and over breccia columns, or a combination of any of these structures. The significance of the mineralized breccia pipe is that it represents the extreme or climactic expression of a structural type which has a variety of mutations including subsidence domes, fracture pipes, and other stockwork zones all with related ancestry and similar to dissimilar characteristics. These allied and associated structures hold an answer to the fundamental question of the origin of many important ore deposits. CANANEA-TYPE LOCALITY FOR BRECCIA PIPES The Cananea district is characterized by an unusual development of mineralized breccia pipes. It is an important copper producer located in Sonora, Mexico, a short distance southwest of Bisbee, Arizona, and at the southerly limit of the great porphyry copper belt of the southwestern U.S. Cananea's rocks consist of Paleozoic quartzite and limestone capped unconformably by a thick series of volcanics including andesitic flows, tuffs, and agglomerates. These rocks have been intruded by a deep-seated granite with related basic and acid differentiates including dikes and plugs of quartz mon-zonite porphyry. Mineralization coincides with a northwesterly trending belt of these intrusives which break upward into and through the sedimentary-volcanic rock sequence. The district has weakly defined tectonic alignments in a northwesterly direction with subordinate intersecting fracture elements, but lacks important faulting or fissuring to provide throughgoing avenues for the upward circulation of mineralizing fluids. Thus, as will be discussed in subsequent paragraphs, the alternate way in which late magmatic and hydro-thermal derivatives of the parent magma reached the near-surface zone was by excavating their own breccia pipe channelways. There are numerous stages of breccia pipe development, related both in time and space to magmatic activity. A compilation of similarities and differences in various pipes suggests that proximity or remoteness of a demonstrable or inferred magmatic source provides an orderly genetic basis for describing the following representative types. Cananea Duluth Type: There are no intrusive rocks within or close to the Cananea Duluth pipe; therefore, the existence of any deep-seated magma that may have been related to its formation must be inferred. The structure is an oval-shaped ring 1200 x 300 ft in plan dimensions, cutting steeply across low angle, bedded tuffs, and other volcanics; it has been developed by drill holes to a depth of 2000 ft below the surface. The ore follows the periphery of the pipe and is composed of intensely brecciated rock which is cemented by minor galena, sphalerite, chalcopyrite, quartz, carbonates, and adularia. There is a definite vertical zoning of sulfides with less galena, continuing sphalerite, and increasing chalcopyrite at deeper levels. Within the interior of the ore ring, the brecciation becomes progressively weaker and coarser, the whole indicating relatively gentle slumping with broken, thin tuff beds pre-

Jan 1, 1961

By E. T. Turkdogan

This is a compilation and a critical review of the data on the Fe-Ca-0 ternary system. Using the results on the reductiorz-equilibria, an oxygen potential diagram is drawn for the greater part of the system. A number of univariant systems and invariant points, not determined experimentally, are evaluated by making use of the theorem on univariant curves intersecting at an invariant point. The formation of solid solutions and ternary compounds and the crystal structures of some of the phases in the composition-diagram are given for a feu! temperatures. DURING the past thirty years there has been a continued interest in the study of the Fe-Ca-0 system. A detailed literature survey made by white1 in 1943 indicated that further work was required to clarify the phase relationships; in fact, the work carried out in the subsequent years, reviewed by Burdese2 in 1954, made a valuable contribution to a better understanding of this subject. Most of the data were obtained by the step-wise reduction of mixtures of iron oxides and calcium ferrites. However, there is some uncertainty about the phase relationships in this system, arising mainly from insufficient use of thermodynamic concepts in the construction of phase diagrams. In this paper an attempt is made to establish the invariant points from the available data. OXYGEN POTENTIAL DIAGRAM Schenck and coworkers3,4 were the early investigators who studied part of this system by the step- wise reduction method and suggested the formation of two ternary compounds, CaO.FeO.Fe2O3 and 2Ca0.5Fe0.2Fez03, the latter being referred to as point X. They also deduced from their results that the phases Y (8.74Ca0.32.5Fe0.8.74Fe2O3 and Z (2.02CaO-97.98FeO) were formed near the w?stite corner of the system. Martin and voge15 postulated the existence of the compounds CaO.9FeO and 4Ca0.3Fe3O4; the former is very close to the composition of point Z and the latter to that of CaO.FeO-Fe2O3. The most valuable contribution to the presen knowledge on this system was made by Cirilli and Burdese6-8 who showed by X-ray and chemical anal yses that there were two ternary compounds, CaO-Fe0.Fe2O3 and CaO.3FeO-FezO3; the former is the same as that suggested by Schenck et al. and the latter is close to their point X. The results of Cirilli and Burdese show that the phases Y and Z postulated by Schenk et al. are solid solutions of calcium oxide in w?stite. In most of the above-mentioned reduction-equilibria measurements carbon monoxide-carbon dioxide mixtures were used and in a few cases hydrogen-water vapor mixtures were employed. Using the

Jan 1, 1962

By ALEXANDER S. CORSUN

THE main orebody in the Hecla mine, Burke, Ida- ho, occurs along a nearly vertical shear zone in the Burke quartzite, with a substantial gouge and lamprophyre dike occurring in an irregular manner throughout the lode. The veins range from 3 to 40 ft. wide and dip from 70 deg. to 90 deg. There is 110 definite line of demarcation between the lode and the wall rock. Stringers of ore are often found in the wall rock for irregular distances. Horizontal but irregular quartz stringers are also found running into the walls and positions of the wall have a tendency to break to the quartz stringers and the accompanying gouge, which causes indefinite, uneven and extremely heavy side and top pressures.

Jan 1, 1930

Jan 1, 1958

By Howard N. Eavenson

From the Pittsburgh coal bed in the four states of Pennsylvania, Ohio, Maryland and West Virginia has been produced an output that, at mine prices, represents a greater value than any other single mineral deposit in the world has yielded.12 While this distinction may in a few years pass to the gold reef of the Witwatersrand, it is possible that eventually, owing to the tremendous reserves still remaining, the ultimate yield of the Pittsburgh bed will be greater than that of any other known single deposit. Considering its importance, not a great deal has been written of its early history and development as a whole; most of the accounts have been of limited localities, or, at the most, of the area within a single state. In "Coal through the Ages" the writer mentioned some references to its early history, but this study will deal not only with its history but with the character of the bed, where and why it was first developed, and its effect upon the states in which it is found. It has not been the intention to write a detailed history of the development of the seam in each locality, as neither time nor inclination were available for doing such work, but only to show the influences that tended to hasten or retard such development. In general the historical matter ends about 1830, when geological surveys began to be made. Some of the maps show data available only since that time, and the sections about coal preparation and coking have been extended to the present time to show the changing conditions. It is believed that the early history includes all published records, and many more sources than those shown in the bibliography were consulted. It is quite likely that some references to coal in this area may be found in the unpublished papers of some of our early soldiers and colonizers, which exist in several libraries, and it is hoped that some future * Dedicated to Dr. Thomas S. Baker, President Emeritus, Carnegie Institute of Technology, whose labors in promoting the International Coal Conferences and in establishing the Coal Research Laboratory have done much in showing the industry how science can be of help to it. Manuscript received at the office of the Institute Feb. 15, 1938.

Jan 1, 1938

By Howard N. Eavenson

From the Pittsburgh coal bed in the four states of Pennsylvania, Ohio, Maryland and West Virginia has been produced an output that, at mine prices, represents a greater value than any other single mineral deposit in the world has yielded.12 While this distinction may in a few years pass to the gold reef of the Witwatersrand, it is possible that eventually, owing to the tremendous reserves still remaining, the ultimate yield of the Pittsburgh bed will be greater than that of any other known single deposit. Considering its importance, not a great deal has been written of its early history and development as a whole; most of the accounts have been of limited localities, or, at the most, of the area within a single state. In "Coal through the Ages" the writer mentioned some references to its early history, but this study will deal not only with its history but with the character of the bed, where and why it was first developed, and its effect upon the states in which it is found. It has not been the intention to write a detailed history of the development of the seam in each locality, as neither time nor inclination were available for doing such work, but only to show the influences that tended to hasten or retard such development. In general the historical matter ends about 1830, when geological surveys began to be made. Some of the maps show data available only since that time, and the sections about coal preparation and coking have been extended to the present time to show the changing conditions. It is believed that the early history includes all published records, and many more sources than those shown in the bibliography were consulted. It is quite likely that some references to coal in this area may be found in the unpublished papers of some of our early soldiers and colonizers, which exist in several libraries, and it is hoped that some future * Dedicated to Dr. Thomas S. Baker, President Emeritus, Carnegie Institute of Technology, whose labors in promoting the International Coal Conferences and in establishing the Coal Research Laboratory have done much in showing the industry how science can be of help to it. Manuscript received at the office of the Institute Feb. 15, 1938.

Jan 1, 1938

Jan 1, 1924

By Thomas O. Ziebold, Robert E. Ogilvie

Experimental analysis of diffusion samples covering the entire Cu-Ag-Au system at 725°C has been carried out. Experimental coefficients are computed at twenty-eight points in the lermary system. It is found that the direct coefficienl for copper is nearly independent of the silver, content for 1ow-silver alloys and that the cross coefficient for silver correlates with the ther-nzodynatnic properlies. This lalter observalion leads to the conclusion that the mobililies of copper and gold are nearly equal. Thermodynarmic actiuilies for Cu-Ag-Au were computed from binary data and adjusted to be consistent with neasured tie lines across the two-phase region which extends into the ternary diagram at 725°C. Application of these therknodynarnic calculaliorls to the dijftcsion data terifies the Onsager reciprocal relations to the extent that experimental uncertainlies will allow. It is jound that diffusion neav the critical point of the 1200-phase field in the isothermal section at 725°C causes the composition gradients for copper and silver to approach infinity while the direct and cross coeficients become equal. From the standpoint of experimental Procedures, it has been shown that microanalysis of ternary samples may be carried out using a simple expression for the conversion of X-ray zntensily to composilion. The accuracy of' this method has been demonstrated by the analysis of standard alloys and by the reproducibility of composition determinations using differed X-ray lines. DIFFUSION in a ternary alloy system is basically and significantly different from diffusion in binary alloys. When only two elements are present there is just one independent composition variable, and the diffusion profile of composition vs distance across a sample must change monotonically through all solid solutions bracketed by the terminal alloys. If two-phase regions are stable for compositions between the terminal values, these must appear as planar interfaces in the diffused sample, with the composition profile exhibiting sharp discontinuities. Adding a third element may alter this picture completely. Because of the additional degree of freedom in the composition, we may see composition profiles which do not change monotonically through solid-solution ranges, and stable, nonplanar phase interfaces. Even though two-phase regions may lie between the terminal compositions of a diffusion sample on the constitution diagram, they will not necessarily appear in the diffusion profiles. In binary diffusion only one coefficient is needed to describe the interdiffusion process. From Fick's law this coefficient relates the diffusive flux of one component to its own composition gradient. In ternary diffusion we must allow for cross interaction between the two independent species. By a linear extension of Fick's law we introduce "cross" or "off-diagonal" diffusion coefficients which relate the flux of one component to the composition gradient of the other independent constituent. Thus, we require four interdiffusion coefficients to describe the transport process in a ternary system. In its most general form,1,2 the rate equation for mass transport by isothermal diffusion in a system of s components states that the diffusive flux of component i, Ji, is a linear summation of all driving forces, Xk, each force being multiplied by an appropriate compliance coefficient:

Jan 1, 1968

Jan 1, 1924

Jan 1, 1962

By Rztssell H. Bennett

A SURVEY of the Mesabi Range iron-ore industry demonstrates that a satisfactory degree of technical progress has been achieved in the last fifteen years. This advance has not been made over a uniform front, but, by salients and bays, according to the different initial positions, economic and technical, of the component producing companies. The producers endowed with rich ore have in general, because of natural advantages, progressed more slowly than their neighbors with leaner properties. The advance has been made step by step all along the line -blasting, loading, hauling and concentrating-and without the benefit of radical innovation. There have been, for instance, no such parallel discoveries in iron ore as leaching and flotation in copper. The much lower unit price of iron operates, of course, to bar the application of these and other practices developed for the higher-priced metals. There exists, however, a radically new concentration process whose technology is well worked out and which may become economically operative in the not too distant future; this, as so often happens in engineering advance, because of recent developments in an entirely unrelated field. First, however, let me devote a paragraph or two to the more important economies effected in mining.

Jan 1, 1932

National Minerals Advisory Council A meeting of the National Minerals Advisory Council on August 3rd in Washington, D. C., indicated the vitally important part that the mining industry is to play in the mobilization program. Director James Boyd of the Bureau of Mines told the Council that the Department of the Interior would review the recommendations of all the Council's commodity committees with regard for mobilization planning in the light of the changed international picture. The Council was requested to reactivate its commodity committees and have them gather all available data on supplies, their sources and availability and present and potential production of the minerals and metals represented on each committee. Data on labor, machinery, transportation, automotive and stationary equipment, power, fuel, lumber, water supply are a few of the important items called for in the reports, which are to be presented at a meeting of the Council on September 1 at Salt Lake City. The material in the reports will become the basis for discussing metal and mineral requirements at that time. Discussion at the meeting bared several $64 questions, probably the most important of which are the following: 1. Which of the war-essential metals and minerals and in what quantities can we reasonably expect to get them from abroad under threat of submarines? 2. How are we going to meet the manpower problem posed by (a) migration of labor from mining to manufacturing since the end of World War II and (b) the draft and the calling up of reservists? Opinion was expressed by industry spokesman at the meeting that the function of complying with mobilization requirements be left to those in the industry itself; that is, those having the "know how." This view contended that any administrating governmental agency should be kept as small and streamlined as possible. There was general sentiment against the reactivation of the wartime Premium Price Plan or other bonus plans as a stimulus to production. The thought was emphasized that what was needed was a change in the basic conditions which have fostered the decline in domestic mining activity in the postwar years. One such condition, long overdue for correction, is the tax structure as it applies to mining enterprises. Many quarters both in industry and in government favor tax relief along the lines suggested in the six tax recommendations by the Council to the Secretary of the Interior last December. The Council adopted a resolution expressing a feeling that the following tax recommendations are still feasible and desirable and will accomplish as much toward increasing exploration for new deposits (thereby subsequently increasing production) as will government loans for exploration: (1) Losses from unprofitable ventures should be allowed corporations, partnerships, or individuals as ordinary deduction against current income. (2) Development costs after discovery should be recognized as operating expenses. (3) Allowance for depletion should be made to the stockholder as well as to the corporation. (4) Income should not be taxed without full allowance for losses of loss years. (5) Adequate allowances for percentage depletion should be made. A discussion of the manpower problem led to the Council's acceptance of a resolution advising that "military authorities should proceed with caution in depriving the mining and metallurgical industry of its manpower." The resolution strongly urged that no personnel "directly engaged in exploration, development, production or supervision (of strategic and critical materials) should be drafted for the armed forces, at least until the anticipated demands upon these producers are clarified." Stockpiles The Munitions Board's "Stockpile Report to the Congress" of July 23, 1950 revealed: (1) The total estimated value of the stockpile objective is $4,051,714,510 at the close of fiscal year 1950. (2) The total value of the stockpile on hand, at the close of fiscal 1950 was $1,556,154,352 or 38.4 pct of the total stockpile objective. An additional $494,948,060 was on order, making a total of 50.6 pct on hand plus the amount on order. (3) Materials obtained for the stockpile by the ECA from January to June 1950 amounted to $13,112,085, while development projects by ECA during this period involved the expenditure of $9,322,000, mainly with counterpart funds. Shortly after the start of the Korean conflict it was felt that Congress ould appropriate greatly increased sums for the purchase of materials for the stockpile. This stimulus to the program may increase the dollar earnings of those European nations that are present or potential contractors in our stockpiling program. Such a development would mean that these nations could add to their gold reserves, thereby stabilizing their respective economies and hastening recovery. This seems to be the picture for the next six months anyway. The "bug" appears when it is realized that the increased threat of total world war actually may retard recovery in Europe as nations on the continent may feel inclined to devote more of their resources to defense programs. Industries Essential to Defense The Department of Commerce in response to a request by the Department of Defense issued on August 3, 1950 a "Tentative List of Essential Activities" as a "guide for calling up for active duty members of the civilian components of the Armed Forces." The list includes the following: Primary Metal Industries. Included herein are establishments engaged in the smelting and refining of ferrous and nonferrous metals from ore, pig, or scrap. Metal Mining. This category includes establishments primarily engaged in mining, developing mines or exploring for metallic minerals (ores). This group includes all ore dressing and beneficiating operations. Anthracite Mining, Bituminous Coal and Lignite Mining, Crude Petroleum and Natural Gas Extraction, Mining and Quarrying of Nonmetallic Minerals, Except Fuels. Challenge to the Mining Industry The source of our country's great strength lies in its capacity to produce. In times of stress such things as national morale and manpower are all-important but without a capable industrial machine we would be helpless. That machine must be fed with minerals and metals in order to generate and maintain momentum sufficient to insure success. Consequences of the lack of adequate supplies of essential metals and minerals to increase and sustain our industrial power are not pleasant to contemplate. It is absolutely imperative that we put forth Herculean effort to guarantee ample supplies of such essential materials as copper, lead, zinc, manganese, antimony, mercury, tungsten, tin, chromite, nickel, cobalt, iron ore and rubber. The mining industry faces a challenge more serious than ever existed before in the history of our country. The industry must be equal to the task.

Jan 9, 1950

THE members arrived at Ticonderoga, N. Y., at noon, Tuesday, October 15th, and were received by Mr. Cyrus Butler, Chairman of the Local Committee of Arrangements. During the afternoon the works of the American Graphite Company and the Horicon Iron Company were visited under the guidance of Mr. Butler, President of both companies, and of Mr. William Hooper, Superintendent. An excursion was then made, in carriages, to old Fort Ticonderoga, on Lake Champlain, after which the party were driven to the Rogers Rock Hotel, on Lake George. The first session of the Institute was held in the parlor of time hotel on Tuesday evening. Mr. Eckley B. Coxe, President of the Institute, opened the proceedings with the following address: I shall ask your attention, this evening, to a few reflections upon the subject of mining engineering as a profession in the United States, its past, its present, and its future, and its duties and oppor¬tunities with reference to the proper development of our great min¬eral resources. Thirty years ago, there were scarcely any mining engineers in this country, and but few in England, and there were no institutions where young men could be educated for the profession in the Eng¬lish language. France and Germany have been able for about a century to boast of mining schools of a high character, that number among their graduates such men as Humboldt, Weisbach, Rittinger, Combes, and Gruner. Of the few we then had worthy of the name of "mining engi¬neer," some had studied in the continental academies, and others were graduates in the school of practical experience, and had learned their profession in mines and smelting-works. Their work con¬sisted principally in making surveys and maps of mines and mining properties, geological reports, and analyses of ores ; but the mining engineer whom we often meet with now, who has studied chemistry, physics, mineralogy, geology, mechanics, and drawing; who is more or less familiar with machinery and its construction, and with the practical management of mines or smelting-works, and who is an expert in some one branch of his profession, would have been very difficult if not impossible to find in the United States. The induce¬ments held out to ambitious and talented young men to enter the

Jan 1, 1879

By J. K. Stanley

Knowledge of the diffusivity of carbon in the low temperature form of iron (alpha iron existing below 910°C) is at the moment of considerable interest in the study of the decomposition of austenite and martensite, the elastic after-effect,123 the magnetic after-effect4 and the decarburization of steel below 910°C. Information on the solubility of carbon in iron, and to a lesser extent its diffusion, is also important in consideration of such phenomena as blue-brittleness, temper-brittleness, "magnetic" aging, quench-aging, strain-aging, and possibly the yield point. In order to obtain more information on these subjects more fundamental knowledge is necessary. It is the purpose of this work to present data on the diffusion and solubility of carbon in the alpha iron. The high temperature form of iron (gamma; face-centered cubic) existing above 910°C is capable of dissolving relatively large amounts of carbon, up to 1.7 pet at 1130°C, while the low temperature form (alpha, body-centered cubic) existing below 910° dissolves only a limited maximum amount of less than 0.02 pet carbon at 725°C, according to data obtained here. Since the solubility of carbon in the face-centered or gamma iron is large, relatively speaking, no great analytical difficulties have been encountered in the determination of the solubility lines5 or of the diffusion of carbon.0 The limited solubility of carbon in alpha iron offers difficulties because experimental procedures and analytical methods for low carbon contents below say 0.01 pet have to be more refined than techniques used for work with gamma iron. Because of the difficulties of applying conventional methods to the determination of the diffusion of carbon in alpha iron, virtually no work has been done on this subject. However, by proper refinement of the analytical method for small amounts of carbon, the determination of the diffusion coefficient can be made readily using modified procedures. The solubility of carbon in alpha iron has been determined over a temperature range by various investigators, but the agreement among them is poor. The present investigation establishes the limits quite accurately. Information of this kind is useful in establishing the correctness of equilibrium diagrams but, more significantly, such information on maximum solubilities, especially when extended to alloyed ferrites, should be extremely important in the study of aging and related phenomena. Literature The literature existing on the diffusion, in particular, and on the solubility of carbon in alpha iron is not extensive. The data which exist are not of a high order of accuracy, much of them being in the realm of conjecture. THE DIFFUSION OF CARBON IN ALPHA IRON Whiteley7 made the qualitative ob- servation, using metallographic techniques, that the rate of diffusion of carbon at the A1 (725°C) point was very rapid and that its diffusion was still rapid at 550°C. Snoek,4 studying the magnetic aftereffect in high purity iron, arrived at the conclusion that the after-effect could be explained by the presence of small amounts of carbon diffusing under the influence of magnetostrictive strain (lattice distortion due to magnetic interaction). In later work, Snoek8 made an estimate of the ratio of carbon diffusion in alpha to its diffusion in gamma iron, and concluded that for a temperature of 910°C the ratio of Da/D? was 2600. Polder,9 basing his calculations of D on relaxation phenomena in the elastic after-effect, estimated that Da is about 1/3 of D? at 910°C (1183°K) and is about 1/12 of Dy at 727°C (1000°K). Polder's equation for the diffusion of carbon in alpha iron was calculated to be 18000 D = 5.2 X 10-4 e-RT cm2 per sec Ham10 obtained data for the diffusion and solid solubility of carbon in alpha iron at two temperatures by using one technique similar to that employed in this study. He found a D of 8.0 X 10-7 cm2 per sec at 702°C and of 2.7 X 10-7 at 648°C. THE SOLUBILITY OF CARBON IN ALPHA IRON Although pearlite is absent in steels containing 0.06 pet,11 0.05 pet,12 or 0.045 pet C,13 it appears that the carbon in these steels cannot be in solution in ferrite. The solubility of carbon at the A1 (725°C) point was first determined by Scott14 on the basis of cooling curves, and was found to be between 0.03 and 0.04 pet C. Tamura15 by interpolating between the solubility of carbon in delta iron at 1400°C and in alpha at room temperature (assuming zero solubility) ar-

Jan 1, 1950

By D. Weinstein, F. C. Holtz

AS a possible method of improving the elevated temperature strength properties of zirconium, an investigation was initiated on the feasibility of producing a dispersion-strengthened material. Because of the high reactivity of zirconium, its high solubility for oxygen, and the stability of the Zr-0 solid solution, the major problem in such a development is choice of a suitable dispersant. Thus, in the present investigation we were concerned primarily with the stability of various dispersants in the zirconium matrix. The experimental procedure consisted of blending powders of zirconium and a dispersant, followed by cold compaction and extrusion. The best available source of -325 mesh zirconium powder contained between 1500 and 3500 ppm Oz; to this material, powders of zirconium carbide (5 p max), vanadium carbide (5 p max), alumina (0.03 p average), lan-thana (0.8 to 2 p), ceria (0.8 to 2 p), yttria (0.8 to 2 p), calcia (44 p rnax), or thoria (0.6 to 0.8 p) were added in amounts of 7 vol pct and compacted at 65 tsi. A cylindrical compact having a density between 70 and 80 pct of theoretical and dimensions of 1 in. diam by 1-114 in. high was thus produced. After canning in copper, these billets could be extruded (5: 1) on a 54-ton capacity, slow-traverse hydraulic press with the billet temperature at 1550°F and the extrusion die at 900°F. However, lack of densifica-tion of some of the extruded billets necessitated ratios of at least 23 :1. Ultimately, all billets were successfully extruded at 1500°F to 0.190 in. diam (32 :I), fully dense rods using a 200-ton capacity press and a ram speed of 90 ipm. The microstructures of as-extruded Zr-7 vol pct LazOS and Zr-7 vol pct Y2Os are shown in Fig. l(a) and (c), respectively. These structures are similar to all the as-extruded materials and consist of an elongated, single-phase zirconium matrix dispersed with oxide or carbide particles. Very little porosity is observed, and the interface between matrix and particles appears satisfactory. The size and distribution of particles, however, are not ideally of the type desired for dispersion strengthening. Since the primary study was of particle stability with respect to zirconium, no attempt was made to overcome agglomeration during powder blending and fabrication. Some areas exhibit fine, well-distributed particles; undoubtedly, a small proportion is submicroscopic and has the

Jan 1, 1963

By J. A. Lund, A. M. Lawson

THE structures of quenched eutectoid and hypereu-tectoid Fe-Cu alloys have been examined by X-ray diffraction and by optical and electron microscopy. The relevant portion of the Fe-Cu phase diagram is given in Fig. 1. Several values have been reported for the solubility of copper in a Fe at the eutectoid temperature, including 1.4 wt pct by orton' and 2.13 wt pct by Wreidt and Darken.2 Alloys containing 4.8 and 7.5 wt pct Cu have been prepared from two batches of Ferrovac E iron (0.005C and 0.013C) and electrolytic tough pitch copper (99.90 Cu). Specimens of dimensions 0.8 by 0.8 by 0.1 in. were cut from hot-rolled material, austenitized, and quenched into brine at 25°C. Similar specimens were also cooled in the furnace, after a short soaking treatment at 1100°C, at a rate estimated to be 10°C per min in the temperature range of 900" to 500°C. X-ray diffractometry was performed on quenched and on furnace-cooled bulk specimens using iron radiation. Only a bcc phase could be detected in all samples. Lattice parameters were calculated from measurements on four lines, made up of two resolved high-angle doublets. Comparisons were made against a silicon standard. Results are shown in Table I. Based on X-ray diffraction studies of a series of alloys of lower copper concentrations, orton' estimated that the tattice constant of a Fe at 25°C increases 0.0014A per wt pct Cu in solution. Extrapolating Norton's data, it may be concluded that all copper was retained in solution in the brine-quenched 4.8 pct Cu alloy, and that approximately 5 pct Cu was also held in solution on quenching the 7.5 pct Cu alloy. Typical microstructures of brine-quenched specimens, as observed by optical microscopy, are shown in Figs. 2 and 3. Precipitation of the E phase (copper-rich) occurred along the y grain boundaries on quenching the 7.5 pct Cu alloy, rendering them readily detectable in the microstructure, Fig. 3. The original boundaries in the 4.8 pct Cu specimens were gener- ally not discernible, however. This indicates that the z phase which was seen in the higher-copper alloy was probably of proeutectoid origin. Thin foils for transmission electron microscopy were obtained from bulk specimens by spark machining to 0.006 in. thickness, followed by electrolytic polishing. Typical transmission electron micrographs

Jan 1, 1967

By S. A. Montague

Mica can claim a considerably greater importance than would be assumed from its comparatively small dollar volume, which came to about $37,000,000 for the United States industry as a whole in 1957. Mica is one of the strategic minerals. We must depend on imports from distant sources for virtually all of our requirements of high grade block and all of our mica splittings. Mica is essential and indispensable for vacuum tubes and high-performance condensers, two electronic components which are vital military necessities besides being nearly indispensable to civilization today. Composition and Properties Mica is the general name for a group of some nine different minerals, two of which, muscovite and phlogopite, are the minerals used by the mica industry as its raw material. Several of the other varieties are commercially useful-vermiculite, * used for heat insulation in expanded form, and lepidolite, used as an ore of lithium while the others-biotite, roscoelite lepidomelane, paragonite and zinnwaldite have little or no commercial importance. Biotite frequently occurs as an undesirable impurity in muscovite. Table 1 lists various properties and other data concerning muscovite and phlogopite. Chemically, mica is a complex silicate of sodium, potassium and aluminum. Most varieties of muscovite are higher in sodium, and of phlogopite in magnesium. There are no important uses of mica where the chemical analysis is important, except that in some uses of ground mica, the content of iron oxide present as an impurity must be kept to a very low limit. Muscovite occurs in a range of color from the so-called India "ruby" which is more closely a pinkish brown, to light and dark green, with numerous other intermediate shades. Ruby color is usually preferred by industry, especially in the better qualities. When split very thin the color in most [ ] micas disappears. Muscovite mica is frequently found containing black and red "stain" as a homogeneous part of the books or sheets. In most cases this stain or impurity is magnetite

Jan 1, 1960