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By J. J. Gilman

Zinc monocrystals, when compressed nearly parallel to their basal planes (within 20), deform in a new way; and certain deformation markings, called "-bands," are typical of this new mode. Characteristics of these bands are described. Mechanical behavior of low angle zinc monocrystals was investigated in some detail. Recrystallization did not occur upon annealing of banded specimens that were free of deformation twins. -Bands do not seem to be the result of nonbasal slip, but rather, a result of a microbuckling mechanism. u-Bands differ qualitatively and quantitatively from ortho kink bands. A dislocation model, consistent with some of the features of u-bands, is described. THE plastic deformation of zinc monocrystals with slip planes (0001) nearly parallel to the stress axis was studied in this investigation. In a previous investigation, it was shown that some low angle zinc crystals (those with slip planes making angles of more than about 2.5+1° with the compression axis), deform by ortho kinking while others (those with slip planes making angles of less than 2.5+1° with the compression axis) deform in a new way.' This new mode of deformation will be described in some detail here. Some of its striking features are: 1—it operates only for compressive stresses, 2—its temperature dependence is anomalous, and 3—it exhibits a new type of "yield-point" behavior. The mode of deformation to be discussed is not new in the sense that no previous evidence of its existence had been reported. The markings that it creates on the cleavage surfaces of zinc crystals have been described by several investigators.'" However, this is the first time that it has been made to operate under controlled conditions so that its response to mechanical variables, temperature, and aging treatments could be investigated and its geometry completely described. Apparently. Jillson' as well as Holden3 and Pratt" believed that the small bands they observed were simply small versions of ortho kink bands. In fact, two of these authors3,6 "alled the markings "micro kink bands." In spite of the precedence, it is felt that this term is not entirely suitable because these bands do not have the same genesis as kink bands, and they are qualitatively different in structure. As will be indicated by later discussion, the bands seem to be related to the tensile deformation bands observed in aluminum. The present author has chosen to call the bands "micro deformation bands," or simply ",ubands," and the deformation process, ''p-banding." Experimental Methods Crystals were grown from 99.999+ pct Zn obtained from the New Jersey Zinc Co. The details of the technique are given elsewhere." It should suffice to say that the crystals were seeded for orientation control, and precision pyrex tubes were used for molding them. About 40 crystals were used, yielding some 130 specimens. Fig. 1 illustrates the typical form of the specimens and shows how the orientation angles are defined. The crystal specimens were usually 1 3/4 in. long and about 150 mil in diameter. The angle between the slip or cleavage plane (0001) and the specimen axis is designated by xo, while a is the angle between the maximum slope of the (0001) plane and the nearest close-packed direction [1210], vary ing from 0°to 30°. The crystals were cut into specimens with a jeweler's saw and the ends were squared by filing (specimens held in V-block). Crystals of this orientation are stiff toward bending, so this procedure introduced only deformation localized at the ends. Then the specimens were polished either chemically in 50 pct HNO³ or electrolytically in 20 pct chromic acid. The mechanical tests were made with an Instron testing machine. This machine weighs by means of electric strain gages on elastic bars and is quite stiff, since the full-load deflection of its load cells is at most 0.002 in. Most of the testing was done at a

Jan 1, 1956

By M. W. Lightner

IN 1947 the steel industry rebounded from its wartime effort and produced a record-breaking peacetime tonnage of steel ingots. During the first six months of the year the industry produced 42,000,000 tons of ingots and expected to produce 85,000,000 tons for the year. With a rated capacity of some 91,000,000 tons, production was at a rate of about 93 per cent of capacity. Credit must be extended to the steel producers who have maintained this steady state of operations while faced with many problems, not the least of which was a continued shortage of satisfactory scrap. Furthermore, the steel industry started a record-breaking peacetime expansion program at a total cost of more than $1,000,000,000. This program will increase the ingot-making capacity of the country by 2,500,000 tons and should be completed in 1948.

Jan 1, 1948

By J. C. Boswell, J. D. Crawford

IN addition to its base-metal and coal mining operations, the United States Smelting Refining and Mining Company has, for the past quarter century, been one of the few large American mining companies interested in dredging. Its activities in this field are confined to gold, and to Alaska, but it is the largest operator in that territory, with twelve huge dredges available to work during the summer on the frozen ancient beach sands at Nome and the gravels of Fairbanks. These operations will be described separately.

Jan 1, 1948

By E. G. SINCLAIR

DRILLING wildcat wells in Wyoming differs a little from methods used in any other field. Here it is always advisable to start the hole as large as is convenient in order to carry each string of pipe as far as possible, so that drilling can be continued a thousand feet deeper if necessary, as there is always sand a few hundred feet ahead that really ought to be tested. This plan may seem ambitious, but if it is adhered to, it will save a great deal of trouble before the well is completed. In making the location, one representative from the operating department and one from the geological department should work together, so that the well may be in the best possible place for obtaining oil and the most feasible place to drill for the operating department. In Wyoming nearly all wells are drilled with standard tools, as with them a better log can be kept and better time made in completing the hole. The shales of Wyoming are very hard and do not mix well in a wet hole. The shale cuts into large pieces, too large to be circulated out of the hole, and forms a mat on the rotary which soon cuts off circulation. Then if this mat cannot be jarred from the bit, the drilling string has to be pulled and the mat cut off from the bit with a pick or an axe. I have seen standard tools come out of a wet hole with 10 to 16 in. of mat on the bottom of the bit. Rotary tools have drilled wells satisfactorily in the Big Muddy field and at Billy Creek, but in the other fields the wells have been drilled much more economically with cable tools.

Jan 1, 1926

By Robert D. Pike

IN November 1939, on behalf of the Harbison-Walker Refractories Co., the author undertook the study of the problem of utilizing the dolomite of northwestern Ohio for the manufacture of calcined magnesia suitable for use in refractories. Grateful acknowledgment is made of the unfailing assistance and encouragement throughout this work from the executive and technical staff of Harbison-Walker Refractories Company. The dolomite of the Niagara formation that is exposed or near the surface of a wide area in northwestern Ohio1 constitutes a vast supply of almost pure dolomite. It offers a virtually unlimited supply of cheap raw material of uniform dependable analysis for the manufacture of magnesia. A typical analysis of dolomite from the vicinity of Luckey, Ohio, follows: [ ] Brines containing magnesium chloride or sea water can be reacted with calcined dolomite to produce magnesia.2,3 In such reactions the MgCl2 of the brine supplies some of the magnesia and the amount of dolomite required is thereby reduced by an equivalent amount, but brines of commercial importance containing magnesium chloride are some distance away from the purest grades of the dolomite of northwestern Ohio. It was decided therefore to concentrate upon the development of a suitable process for separating the lime and magnesia of dolomite, depend¬ing upon the dolomite itself as the sole source of magnesia. This would make it possible to place a plant at the dolomite quarry, thus eliminating the cost of transporting the stone and also rendering the calcined magnesia available at a most convenient production point, considering the cost of delivery throughout the steel industry. The selection of a process depending solely upon the dolomite as a source of magnesia also necessarily entails production of the lime content of the dolomite as a by-product. It was recognized that if such a lime by-product could be produced in a suitable form, a plant location in northwestern Ohio would also be advantageous for marketing the lime. The problem, therefore, was the discovery and development of a low-cost process for separating the magnesia and lime of the dolomite of northwestern Ohio and producing each in a form relatively free from the other, and meeting the respective requirements of established markets. A satisfactory solution of this problem has been found, and it is the

Jan 1, 1947

By H. L. Couch, J. D. Lubahn

In decarburized mild steel, the strain hardening arising from 1/2 pct strain can he partly recovered by subsequent heating, even though re crystallization or grain growth does not occur. This recovery varies from 5 pct in an hour at room temperature to 70 pct at 800°C. The variation with temperature was qualitatively similar to that reported for copper, but occurred at lower temperatures. Except for the initial portion (Bazdschinger effect), the stress-strain curve following recovery can be superimposed on the original curve by shifting it to the left. In other words, the tensile behavior is essentially the same after straining and heating as if there had been less strain and no heating. The importance of this observation in understanding simultaneous deformation and recouery is explained. AN earlier investigation1 on copper showed that strengthening due to strain hardening was augmented by heating at moderate temperatures, but was diminished by heating at higher temperatures, Fig. 1. Auxiliary experiments1 indicated that recovery and strain aging are independent processes, which may proceed simultaneously, and whose effects are additive as indicated in Fig. 1. In order to study recovery by itself, similar tests were made on decarburized mild steel, where strain-aging effects are known2 to be absent. MATERIAL, TESTING PROCEDURE The specimens were made from rimmed, hot-rolled SAE 1020 steel 0.040 in. thick, by stamping out rectangular blanks and end holes, Fig. 2, and pack milling the reduced section. These were wet-hydrogen treated2 for 16 hr at 720°C to remove carbon and nitrogen completely and then heated 1 hr at 850°C in vacuum to stabilize the grain size. Auxiliary ex- periments showed that heating up to 800°C will not cause grain growth. They were prestrained 5 to 7.5 mils per in. using the special grips shown in Fig. 2. Such small strains are less than the "critical" strain for recrystallization and, therefore, will not cause recrystallization, even at high temperature. The recovery treatment after prestraining and before the retesting consisted of heating for 1 hr in wet hydrogen at the desired temperature. In one test, Huggenberger gages were used to define more accurately the loading and unloading curves. Fig. 3 illustrates the creep during the early stages of unloading, the hysteresis due to cold stretching, and removal of hysteresis by heating.3 RESULTS The load-deflection curves had ratner widely differing shapes for different specimens, both before and after the recovery treatment. Some specimens showed perfectly smooth curves, Fig. 4, while others exhibited an inflection more or less suggestive of a yield point (Fig. 4 shows all extreme case). Some curves were much steeper than others; Fig. 5 shows two extremes. Some additional ex-

Jan 1, 1960

By Bruno Nordberg

THE high cost of coal in Butte and the development of large amounts of cheap electric power from the Missouri river caused the Anaconda Copper Mining Co. in 1908 to make an investigation as to the possibility of adapting this cheap electric power for the operation of their many large hoisting plants. At this time electric power had already been adopted for practically all other power purposes around the mines, such as pumping, compressing air, etc. The map (Fig. 1) shows the location of the mines of the Butte mining district. These mines are located within a circle of approximately a 1-mile

Jan 9, 1913

By David W. Brunton

FROM the old-fashioned " grab-sample " to the modern timing- . device, which takes a machine-sample with mathematical precision, there is a wide gap which was only crossed' by many years of toil and unremitting endeavor. Even to-day, notwithstanding the advancement in the art, "grab-sampling" is still practiced-sometimes to afford the unscrupulous mine-promoter a basis for fairy-tales with which to entrap the too-gullible investor, and often by milling and smelting companies to determine the amount of moisture in custom-ores. The latter practice is almost as reprehensible as the former, and it causes more trouble and ill-feeling between seller and buyer than all other factors put together. No reputable concern to-day would think of attempting to determine by grab-sampling the amount of gold, silver, lead, or copper contained in an ore, and yet many buyers expect the miner to accept the results of grab-sampling in the determination of the amount of water contained in the ore, forgetting that accurate results are just as necessary here as in the determination of the metals, because the result determines the percentage of weight of the ore which shall be excluded and considered to have no value whatever. Samples for the determination of moisture should be taken with as great care as samples for the determination of. metallic content, and in order to avoid the extra expense of a separate operation moisture-samples should be taken from the sample-safe. As the sample reaches the sample-bin in a smaller stream and by a more circuitous route than the "reject" travels in its path to the outgoing car, it loses more moisture en route, and a constant should be added to compensate for this difference. Carefully-conducted experiments have shown that the difference in loss of moisture between the two routes does not exceed 10 per cent. in summer and 7 per cent.. in winter. For instance,

Aug 1, 1909

By W. C. PAGE

AS the pioneer operation treating the mixed lead- zinc-iron ores from the district tributary to the Salt Lake Valley, the International Smelting Co.'s plant has offered an extremely interesting and instructive opportunity to study some phases of this problem. Basically, there were two main reason for our attempting to work out a successful operation for the separation and concentration of the values contained in the rather widespread deposits of these so- called lead-zinc ores. In the first place, the time was ripe and demanded some method of curtailing the economic waste resulting from the costs of past and present practice of smelting ores of this character, or rather, those ores which could stand the charges inherent with smelting them. Secondly, but rather primarily with us, we believe that such a solution would greatly in- crease in general the production of lead in the district tributary to the Salt Lake Valley. It is generally known that there were and are three relatively large lead smelting plants in the Salt Lake Valley and the decreasing production of correspondingly clean lead ores was not efficient to justify the existence of all three. We could not hope for better lead smelting metallurgy nor more efficient business management than was being practised, so the only prospect was to at- tempt to work out some way to increase the primary production and thus widen the scope of operations.

Jan 1, 1926

By A. B. Kinzel

ALTHOUGH calcium carbide and other compounds of calcium, as well as a number of calcium alloys, are well known and are the basis of important industries in the of United States, calcium metal has been thought of as something of a rarity and has received comparatively little attention from industrial metallurgists. The metal may he made in a number of ways, but the electrolytic deposition of calcium from a molten calcium chloride bath was the first process to be used for its commercial production and is still the standard procedure. Calcium metal has elicited little interest among nonferrous metal producers, as the demand has been relatively small and its production restricted to only a few plants, exclusively in France and Germany.

Jan 1, 1941

MORE than 5000 miners and suppliers descended upon Denver to make the American Mining Congress' four-day metal mining show one of the most extravagant equipment displays ever assembled in one place at one time. The most recent developments in equipment for mining, milling, and processing ore were shown by the 146 exhibitors at Denver's new City Auditorium which covers 57,000 sq ft of floor space. Other displays were placed in the open air opposite the auditorium site. Registration desks were opened Sunday, Sept. 21. A field trip to the Colorado School of Mines at Golden was the featured activity of the day. Official opening of the show took place on Monday, and presided over by Howard I. Young, president of American Zinc, Lead & Smelting Co.; Otto Herres, vice president, Combined Metals Reduction Co.; William J. Coulter, vice president, Climax Molybdenum Co.; Charles B. Stainback, Westinghouse Electric Corp.; and Merrill E. Shoup, president, Golden Cycle Corp. Convention welcoming addresses were delivered by a representative of Mayor James Q. Newton, of Denver, and Gov. Daniel V. Thorton of Colorado. Following the formal opening ceremonies a round table discussion dealt with the "Paley Commission Report" formally called Resources for Freedom. Participating in the panel were: Arthur H. Bunker and George R. Brown, members of the Paley commission; H. I. Young, president of the American Mining Congress; Horace M. Albright, president of U. S. Potash Co.; Evan Just, vice president, Cyprus Mines Corp.; Donald H. McLaughlin, president, Homestake Mining Co.; E. H. Snyder, president Combined Metals Reduction Co.; Simon D. Strauss, vice president, American Smelting & Refining Co.; Sen. H. C. Dworshak (R.-Idaho) ; Ira B. Joralemon, consulting engineer; Jess Larson, De fense Materials Procurement Agency; and Andrew Fletcher, president of St. Joseph Lead Co. The panel discussed the report for six hours, adding a great deal of information to the already voluminous amount which has been gathered concerning it. Three objections to the report frequently mentioned were: 1-the multilateral contract; 2-international buffer stocks; 3-international buffer stocks combined with limited quota arrangements. Points on which the panel commended the report were its recommendations for acceleration of topographic and geologic mapping of the United States and Alaska; recognition of the principle of percentage depletion for metals and minerals; and advocation of removal of the present limitations on the expensing of exploration costs applicable to minerals. Technical sessions were held throughout the four days of the meeting. Included in the program were: Progress in Mechanication; Small Mines; Public Lands; Open Pit Mining; Manpower-Labor Relations; Shaft Sinking; Roof Support; Taxation, Gold, Silver and Monetary Policy; Advances in Mill Practices; Special Conference on Strategic Materials; Uranium Mining-Atomic Energy; Prospecting and Exploration; New Metallurgical Processes; and Rock Breaking. About 45 papers and several panels were presented during technical sessions. Formal and informal social functions consumed the remaining time of the convention. Three locations were needed to handle the huge throng attending the Mining Jamboree Monday evening. The only other sponsored social function took place Thursday evening. A great many informal gatherings, chiefly convivial, were held in manufacturers' courtesy rooms-called wet stopes. Field trips included Cripple Creek, Pueblo, Climax -Leadville-Gilman, Colorado Plateau-Grand

Jan 1, 1952

By William H. Shockley

[SECRETARY'S ]NOTE.-The following notes, arranged and edited in this office, but not yet revised by the author, were placed at my disposal with much modest hesitation (due to their incomplete and fragmentary character), upon my earnest request, and my argument that such recent and trustworthy data concerning a new and important mining industry ought not to be withheld from our Transactions, simply because they are not sufficient to constitute a, complete academic treatise on the subject. This argument is recommended to the attention of many other members, who are waiting for the opportunity to contribute something "monumental" to our Transactions. In a number of instances, death has nulli¬fied this ambition, and the intended "monumental" contribution has turned out to be an obituary notice by the Secretary, instead of a valuable record of the professional experience thus hopelessly lost to the world.-R. W. R.] The official publications of the the Russian Government give fairly complete statistics of the dredges operated in the Empire; and in a recent English bluebook, Mr. Cook's report on Siberian Trade presents a brief account of dredging in Siberia. The data in Table I. (not given by Mr. Cook) have been taken from the Gold Mining Messenger (Russian) for July, 1905. These interesting statistics, though incomplete, show that the Yenisei dredges are working on poor ground and yield small returns. According to report, but few yield a profit exceeding 10 per cent. per annum on the capital invested. In the summers of 1904 and 1905, I traveled in the Urals as far north as lat. 61° N., long. 61° E., on the the Lozva river, a part of the vast system of the 01) river. This clear-water stream starts from the summits of the Urals at an altitude of 4,000 ft., and flows through a flat country, densely wooded with larch, spruce, pine, fir, birch and poplar. The river is full of fish, and is navigable for good-sized steamers as far as Ivdell. Winter lasts from early November to late April, the temperature rang¬ing from -60° F. to a summer maximum of 90° F. The rain¬fall is 20 in.. The climate is healthy, although mosquitoes,

Jul 1, 1906

By S. H. Penn

One of the more challenging aspects of the unfolding age of space travel centers about the opportunity for man to use the natural resources of other worlds. The first of the extraterrestrial worlds to be exploited will be the moon. After only a scant few thousand years of scratching the earth's crust, man will embark upon a venture that for centuries has excited the imagination of many (while staggering that of most) and may become a reality within the next decade. There has never been a time when so much money and effort will have been expended to exploit an area about which so little is known. Paradoxically, this effort combines much of the detached objectivity so typical of our analytical time with the proverbial optimism of the indefatigable prospector. As the earliest manned lunar missions will be brief and exploratory in nature, astronauts will not be expected to attempt to exploit any of the possible lunar natural resources. In later missions, with a more extended period of time available for the astronauts to stay on the moon, it may be desirable or even necessary to "live off the land". The resulting exploitation of lunar resources will be intended primarily to reduce the dependence of manned missions upon terrestrial logistic support and to reduce the cost of maintaining lunar bases.

Jan 3, 1966

By Pierre de P. Ricketts

Having had occasion while in Europe during the past summer to visit some of the foreign mints and assay offices connected with the same, I thought a brief description of the general process of coining employed, and such items connected with assaying as were new, might prove interesting to the Institute. The principal foreign mints are: the Royal Mint, London; and the mints in Paris, Brussels, Utrecht, Berlin, Vienna, Copenhagen, St. Petersburg, Stockholm, Madrid, Milan, Rome, and Constantinople. My time only permitted my visiting a few of the principal and largest given in the list, and for a description of the remainder I am indebted to the kindness of Mr. James M. Napier, who in company with the deputy master, and chemist of the Royal Mint, made a complete inspection of all the European Mints in 1870.

By Pierre de P. E. M. Ricketts

HAVING had occasion while in Europe during the past summer to visit some of the foreign mints and assay offices connected with the same, I thought a brief description of the general process of coining employed, and such items connected with assaying as were new, might prove interesting to the Institute. The principal foreign mints are: the Royal Mint, London; and the mints in Paris, Brussels, Utrecht, Berlin, Vienna, Copenhagen, St. Petersburg, Stockholm, Madrid, Milan, Rome, and Constantinople. My time only permitted my visiting a few of the principal and largest given in the list, and for a description of the remainder I am indebted to the kindness of Mr. James M. Napier, who in company with the deputy master, and chemist of the Royal Mint, made a complete inspection of all the European Mints in 1870.

Jan 1, 1876

By George K. Foster, Charles D. Borror

THE Jeffrey mine of the Canadian Johns-Manville Co., Limited, is in the town of Asbestos, situated approximately 100 miles northeast of Montreal and about the same distance southwest of Quebec, in Richmond County, Quebec. Mining operations were started in 1881 on outcrops on a hill, as a side-hill cut, followed by a second and third cut. This development was the forerunner of the present large open-pit operations, the mine now ranking as the largest openpit asbestos mine in the world. Operations were first carried on by hand, then by horsepower and later by stem cableways. By 1924 the derrick spans, 2000 ft. or more long, became unwieldy. To overcome this, and also to eliminate hand labor as much as possible, steam shovels and railroad haulage were introduced. The steam shovels were replaced in 1928 by larger electric shovels of the full-revolving type. THE ORE BODY The ore body is a serpentinized peridotite rock mass. The chrysotile fibers form a network of veins throughout, varying from microscopic width to two or more inches measured across the veins (Fig. I). These veins may be continuous for a few or many feet; they may increase or decrease in width within a few feet. The veins in which the fibers occur perpendicular to the veins are known as cross fiber. Those in which the fibers lay parallel to the veins are known as slip fiber. The cross fibers are of better quality, and more in demand. The majority of the fiber [ ]

Jan 1, 1946

By W. C. Ralston

This note will give the cost of driving an adit at the Melones mine, in 1898, and, for purposes of comparison, the cost of similar work, in 1888, at the Hogsback mine, Placer county, Cal. The property of the Melones Consolidated Mining Company is situated on the Mother Lode of California, on Carson Hill, near Robinson's Ferry, and adjoins on the south the famous Morgan mine. The Mother Lode of California extends for a distance of over 100 miles in length through several counties, with a general strike of northwest and southeast. Three veins (commonly called the east vein, middle vein and west vein) comprise the " lode " in this section. The Melones property is situated upon the east and middle vein, and includes 1407 feet on the east vein and 5166 feet upon the middle vein. A shaft had been sunk on the Reserve mine, which is on the east rein, and within 230 feet of the Morgan mine. At the bottom of this shaft drifts and cross-cuts had been run and a large body of ore developed. It was deemed advisable by the Melones Mining Co., which holds this property under bond from the Melones Consolidated Mining Co., to run a tunnel and develop this body of ore at a greater depth. An option was obtained upon the South Carolina mine, which adjoins the property on the south, and is on the same east vein, upon which a tunnel had been run a distance of 1080 feet. This tunnel was cleaned out and continued to a point within forty feet of the Morgan mine. It passes directly under the Reserve shaft, 425 feet below the 200-foot level. The additional length of tunnel to be run was 1923 feet, and

Jan 1, 1899

By Walter G. Perkins

T SEEMS almost sheer presumption to attempt' to discuss Russia in its present chaotic political and economic condition, and were it not that at least two certain absolute factors are continuously at work, it would be impossible to' even approach the subject with any degree of intelligence. These are the inborn love of peace of the people and the national character of the cooperative movement. The love of peace inborn in the soul of every Russian, the desire to be left alone and to- live his life among his home village surroundings, is probably one of the two greatest factors that will make the continuance of the present conditions of civil war impossible. One army or the other may sweep up and down the country. but the Russian peasant will: remain in his own village if not literally darken out. This love of peace is evidenced by the fact that there is no country where personal safety is greater than in Russia in normal times. I have traveled in many isolated parts, carrying considerable sums of money and persolial equipment that; in itself, would be a fortune to any peasant, and have never even encountered a condition in which the most wildly imaginative person looking for adventure, 01: trouble, could muster up even a suspicion of fear. This statement applies also to Southern Siberia and Northern Turkestan, which are inhabitated by the nomadic tribes of Khirghese origin.

Jan 1, 1920

By Russell C., Fleming

FOK, many years the officials of the Magma Copper Co. mine at Superior, Ariz., have had to contend with adverse conditions underground in the form of high rock temperatures, hot water, and high relative humidity. These conditions in the mine have been such that working the mine would have been impossible were it not for the constantly expanding and improved sys- tem of ventilation to produce bearable conditions in the working places. Results that have already been achieved make an interesting study of what can be done along those lines. From the time the mine was first opened in 1910 it has been hot. An idea of the conditions that have persistently been encountered can be obtained from parts of the mine that are not being worked at present or that do not yet have sufficient ventilation. Virgin rock temperatures as determined in drill holes at the faces range from 104° to 116°*. An observation made at the face of No. 5 West footwall drift on the 2800-ft. level.

Jan 1, 1930

By A. C. Fraker, H. H. Stadelmaier

In the systems Mo-Fe-C, Mo-Co-C, and Mo-Ni-C the phase boumdaries of the cubic Ij carbides were determined at 1000°C and the variation of the lattice parameter with composition was measured. In the system Mo-Fe-C a single ternary carbide, Mo3Fe3C, was observed. In Mo-Co-C and Mo-Ni-C two new n phases of the type M12C were found: Mo6C06C and Mo6Ni6C. At 1000°C they coexist with the M6C phases MO3-4,CO3-2C and Mo3-4Ni3-2C, respectively. Mo3C03C and Mo4C02C are not separate phases but parts of a single M6C phase region, and the same is true of Mo3Ni3C and Mo4Ni2C. THE n carbide structure type has been known since it was determined by westgren' in 1933, yet reliable information on phase compositions of this type is ap-parently scarce. The following selection of suggested formulas illustrates the extent of the confusion con-cerning compositions: W2-3Fe4-3C,1W6Fe6C,2 W2_4Fe4-2C,3 (W,Fe)6C,4 Tj.-W4Co2C and nz-W6Co6C,5 n1-W3Co3C and n2-w4Co2C,5 W3C03C and w6Co3C2,7 MO3Fe3C,8n2-M04Fe2C,9 (MO,Fe)6C,4 MO3CO3C,8 n2-MO4CO2C.9 Many of these compositions obviously overlap, some disagree in carbon content. The use of the designations 77, and n2 is not consistent. There is uncertainty whether two carbides M6C coexist or whether there is only one M6C with a wide range of substitution of one metal for the other. The existence of M12C seems questionable altogether if one ignores the results of a neutron diffraction study of W6Fe6C supporting that particular metal to carbon ratio.'' More reliable information is available for the iso-typic oxides studied by Nevitt,11 Nevitt, Downey, and orris," and Meussner and carpenter.l3 That n car-bides and oxides are structurally identical, particularly with respect to the location of the metalloid atom, has been demonstrated clearly by Stadelmaier and Meussner14 and also by Parthe, Jeitschko, and sadagopan.15 Therefore the present paper, which attempts to establish the phase boundaries of n defini-tively for three carbon systems, has implications for the whole family of filled Ti2Ni types. EXPERIMENTAL PROCEDURE The samples were prepared in two stages. Pellets weighing 3 g were compacted from powders of the elements and presintered in a closed tube of fused silica that had been evacuated to lO-4 mm Hg. This was fol- lowed by arc melting the sintered samples under argon. Remelting the button once was sufficient to produce homogeneous specimens. The metal powders had the following minimum purities in wt pct: molybdenum 99.5, iron 99.0, cobalt 99.7, nickel 99.9, graphite 99.94. Carbon determinations by the gas volumetric method were obtained from thirty-one of the one hundred samples in the annealed condition. They were limited to compositions that were critical to placing a boundary line in the isothermal sections. The carbon losses were comparatively low and averaged less than 1.5 at. pct. For annealing, the samples were sealed in tubes of fused silica evacuated to 10-4 mm Hg. The annealing schedule was 20 hr at 1250°C followed by 150 hr at 1000" ±10°C. For the water quench the silica glass tubes were broken mechanically to speed the quench. The specimens were examined in the as-cast and annealed condition by standard metallographic techniques. Some of the as-cast and all annealed samples were studied by X-ray diffraction using a 114.6-mm powder camera with filtered Co radiation. The lattice parameters of the n phases were determined by graphic extrapolation to 8 = 90 deg on a plot against sin2 8. It is estimated that the maximum error in the lattice parameters is ±0.002A.. The phase fields were determined by the disappearing phase method, relying on X-rays for phase identification and on microscopy to detect small amounts of a phase. RESULTS Pertinent information on the binary side diagrams has been summarized by Hansen and Anderko16 and Elliott17 and will not be discussed further. Photomicrographs documenting the equilibria at 1000°C have been selected to avoid redundancy due to the similarity of the three systems. Thus there will be only one picture showing an equilibrium with Mo2C, and so forth. Molybdenum-Iron-Carbon. An isothermal section of most of the Mo-Fe-C system at 1000°C is shown in Fig. 1. No attempt has been made to distinguish between a and y iron or to determine their phase boundaries. A conspicuous absence is the phase Fe2 1Mo2C6 with the Cr23C6 structure, supporting the suggestion by Krainer4 that it decomposes by annealing at high temperatures. The only ternary phase is found in a narrow range around Mo3Fe3C (MO43Fe43C14). A microstructure with a two-phase mixture of Mo + n is seen in Fig. 2. The variation of the lattice parameter of n with the estimated composition is shown in in Table IA. The phase diagram does not agree with the results of Kuo9 who reported n2-Mo4Fe2C. Our lattice parameter Varies from 11.095A at the iron-rich end to 11.140Å at the molybdenum-richoend of the phase field whereas Kuo9reported 11.26Å for Mo4Fe2C. We are in agreement with the older work

Jan 1, 1970