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By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of cobalt has been investigated by Ruder and Birchenall,1, 2 Nix and Jaumot,3 and Gruzin.4 The results for a given tem- perature differ by a factor of about six in the extreme cases with no really close agreement between any two sets of data. The first two groups of investigators employed the decrease of surface activity method. Since Ruder and Birchenall have shown that the values obtained from this method are sensitive to the surface preparation, it seemed desirable to perform a few check experiments by a method not open to this objection.

Jan 1, 1956

By E. H. Greener, M. E. Fine

The internal friction (1/Q) of cobalt Fig. 1 (measured by an electrostatic dynamic method1) near 250°C begins to increase rapidly on heating and continues to increase until 560°C, the highest tem- perature measured. In the plot of log of 1/Q against 1/T, above 250°C the data nearly fit two straight lines intersecting at 400°C, approximately the temperature of the hexagonal-cubic transformation. The higher temperature branch corresponds to an effective activation energy of 6500 cal per mole, the lower temperature branch 11,000 cal per mole. Young's modulus Fig. 2 increases approximately

Jan 1, 1959

By F. M. Sandoval, R. E. Ries, J. F. Power

Returning the original soil material to the surface of smoothed mine spoils is a practical means of restoring agricultural productivity. Research has established that high-sodium spoils in North Dakota: (1) must be covered with about 70 cm of soil material to achieve maximum production; (2) top-soil must be segregated and spread separately from subsoil; (3) potential production depends on the quality of the soil material returned; and (4) erosion and upward salt movement must be controlled for sustained production. Erosion is best controlled by reducing final grades as much as possible during the smoothing process followed by prompt establishment of vegetation.

Jan 12, 1979

By Roberto Pimentel de Souza, Helder Zenóbio

VRD started producing pellets in 1969 with one 2-million-t straight grate plant. In the beginning of April 1973, the second unit came on stream with an additional capacity of 3 million t/a of pellets. In January 1977, the third unit started, bringing the annual capacity to 8 million t/a. In the coming year (1978-79), three more units, 3 million t each, are expected to begin production. CVRD's experience with different binders and additives is described. Over the years several kinds of pellets have been produced to satisfy market requirements. General quality information is given for each.

Jan 1, 1981

By William E. Ford, Edward Salisbury Dana

1. Normal Class (28) Gypsum Type 2. Hemimorphic Class (29) Tartaric Acid Type 3. Clinohedral Class (30) Clinohedrite Type Mathematical Relations of the Monoclinic System Crystallographic Axes. - The monoetinic system includes all the forms which are referred to three unequal axes, having one of their axial inclinations oblique. The axes are designated as follows : the inclined or clino-axis is a; the ortho-axis is b, the vertical axis is c. The acute angle between the axes a and c is represented by the letter 0; the angles between a and b and b and c are right angles. See Fig. 331.

Jan 1, 1922

By William L. Lennemann

Chemistry of uranium with respect to its hydrometallurgical recovery from carnotite ores was investigated and well defined during the radium boom period between 1900 and 1920. Since that time, methods used to extract uranium from its ores have remained basically either acid leaching or sodium carbonate leaching. Until about 1950, the only practical methods known for achieving a better than 75 pct U2O3 concentrate from the leach liquors involved fundamental chemical techniques for either purifying a solution prior to the uranium precipitation, or refining a crude uranium concentrate that was produced by neutralizing a pregnant mill liquor.

Jun 1, 1956

By K. H. Nimerick

A recent study has attempted to identify properties of hard-to-float coal that make them responsive to froth conditioning. Froth conditioning is the process of chemically enhancing the hydrophobic surface character of fine coal particles to improve their recovery by froth flotation. Since its introduction, froth conditioning has enabled recovery of an additional 1.9 Mt (2.1 million st) of coal. This study correlates field results to chemical, physical, and petrographic properties. The most direct correlation relates the coal's oxygen content to its response to froth conditioning. The higher the oxygen content, the greater the benefits of froth conditioning.

Jan 1, 1985

By A. Werenfels

No PETROLEUM, in commercial quantities, is found in France except the small production of the Pechelbronn field (Fig. 1) in Alsace, which produced 75,000 tons in 1923; therefore the test of the petroleum prospects of the Limagne is most interesting. Under the superintendence of M. Termier, chief engineer of the French mines, a well near Crouelle (Fig. 2) was drilled in 1921 to a depth of 856.3 m. (2808 ft.); at different depths favorable showings were encountered. The well, however, was abandoned because of drilling difficulties. A second one is now being drilled near the same place.

Jan 1, 1925

By T. K. Redden

Protective coatings based on the formation of a surface coating of nickel aluminide (NiAl) were applied to the nickel-base superalloys IN 100, SEL 15, and U-700. Coated specimens were exposed to an oxidizing environment at temperatures between 1600 and 2200 F for times up to 1000 hr. The oxidation resistance and stability of the coating were evaluated by weight gain measurements, metallographic examination, and X-ray diffraction study of surface oxides and coating. The composition of the coating and diffusion zone was determined by electron microprobe traverse of samples before and after high-temperature exposure. Intermediate phases formed in the coating and diffusion zone were identified by X-ray diffraction in situ and after electrolytic extraction. The outer coating was found to consist of the inter-metallic compound, NiAl, while the diffusion zone contained MC, M23C6 or M6C carbides, and a phase in a matrix of NiAl + Nidl. Oxidation resulted in formation of an A1203 n'ch scale containing some Tz02. Depletion of aluminum during oxidation resulted in degradation of the outer coating to Ni3Al and the nickel alloy matrix. Diffusion of aluminum into the base metal was found to be slight and did not influence coating life significantly. The o formed in the diffusion zone during coating decomposed during elevated-temperature exposure to form stable carbide phases characteristic of the base metal. Diffusion zone phase changes were found to have no effect on the life of the aluminide coating in the oxidizing envzron?nent. THE oxidation resistance of many high-strength nickel-base superalloys is inadequate for extended exposure at temperatures above about 1600°F. In addition, some applications for these materials require that they be exposed to environments containing sulfur compounds and sodium salts which can cause surface attalk known as sulfidation or hot corrosion. In order to provide the necessary corrosion resistance to the high-strength alloys, protective coatings based on an aluminizing process have been developed. These processes, usually based on a pack cementation technique, result in the formation of a NiAl-rich outer coating layer either during the coating process or by a subsequent diffusion treatment. The performance of the aluminide coatings is affected by interactions between the coating layer and the base metal both during the coating process and during subsequent exposure at elevated temperatures. Knowledge of these interactions is required to guide the development of coatings capable of longer life and improved reliability. Goward et al.' recently reported the metallurgical factors which influence coating per- formance on MAR-M200. The present work is concerned with correlating the interactions and performance of coating compositions on several representative materials. EXPERIMENTAL PROCEDURES Materials. Three cast nickel-base superalloys which are used for turbine buckets in air-breathing engines were studied: IN 100, U-700, and SEL 15. Their chemical compositions are given in Table I. The alloys were vacuum-induction-melted and cast to slabs approximately 0.3 in. thick from which rectangular specimens 0.25 by 0.5 by 1 in. were machined. Coating Procedures. The machined specimens were coated by CODEP processes which were developed at the author's laboratory. These are based on pack cementation in various media to deposit either aluminum or aluminum in combination with titanium. The coating process which deposits only aluminum is designated CODEP-C, while the CODEP-D process deposits titanium in combination with aluminum. The CODEP-D process was applied only to IN 100. Both CODEP processes are applied at 1950" or 2000°F for 4 hr without need for a subsequent diffusion treatment. An outer coating about 1 mil in thickness is produced by these processes. Test Procedures. Coated specimens were exposed to static oxidation for periods ranging from 24 to 1000 hr at temperatures of 1600" to 2200°F. Terminal weight gain measurements and visual examination were used to evaluate oxidation resistance. including oxide spalling and coating failure. Both as-coated and exposed specimens of each alloy were studied by metallographic examination, electron microprobe analysis (EMA), and X-ray diffraction analysis either of the exposed surfaces or of phases extracted from the coating and diffusion zone. RESULTS As-Coated Condition. The microstructures of as-coated conditions were generally similar, irrespective of base materials or the particular coating process. They are typified by IN 100 coated by CODEP-D as shown in Fig. 1. The predominately single-phase outer layer, area A, Fig. 1, was identified by X-ray diffraction as the intermetallic compound NiA1. The NiAl zone extended inward to the original base metal interface. The diffusion zone, area B, Fig. 1, included carbide phases, a lamellar phase oriented perpendicular to the base metal surface, and a matrix phase consisting of a mixture of NiAl and Ni3Al. The phases in the diffusion zone were electrolytically extracted using a 10 pct HCl in methanol solution at approximately 1.3 amp per sq cm. The extracted phases were found to be M6C, MC, or M=C6 carbides and o as shown in Table I1 for each of the alloys. The d spacings from a typical diffraction pattern are

Jan 1, 1969

By R. C. Dorward

DIFFUSION considerations are necessary to describe many technologically important metallurgical and physical processes. Since most commercially important alloys are comprised of more than two components, diffusion calculations applicable to binary systems are often unjustified. However, in many instances the more general equations valid for three-component systems may be employed. The phenom-enological description of ternary diffusion is now well-established,1-4 and the theory has been applied with some success to a few practical situations.5"7 The flux equations for the solutes (components 1 and 2) of a ternary solution may be expressed by:

Jan 1, 1969

American Bureau of Metal Statistics, 33 Rector St., New York, N Y. It is not the policy of this publication to include reference to works issued by commercial publishers except where it is felt that the publications have a unique value, particularly, works of a statistical nature The American Bureau of Metal Statistics issues a Year Book of this nature, summarizing important statistics of nearly all of the nonferrous metals Published about the end of May each year. Price, $2. Interim Reports, mostly monthly, in mimeographed form, are also available to suscribers on a scale of terms

Jan 1, 1933

By Richard A. Conkling

D. W. OHERN, Oklahoma, Okla. (communication to the Secretary*). -The author states: "A shale layer buried beneath 2,000 or 3,000 ft. of strata, in some instances, will upon folding become thicker in the synclines and thinner on top of the anticlines." In any series of folded strata there is a level of no strain. Provided the strata do not slip on each other, there would be above this level a thickening of strata in the synclines and a thinning on the anticlines, as the author states, while the converse would obtain below this level. In order that the author's

Jan 3, 1917

By P. Barnes

(Read at the Wilkes-Barre Meeting, May, 1877.) IN vol. 33 of the Proceedings of the Institution of Civil Engineers, London (part 2, for 1870-71), may be found a statement of the cost of two blast furnaces, together with a somewhat detailed description. The attempt will be made in this note to restate these items of cost, so that the information may be rendered perhaps more accessible to our members than in its present place of record, and also in order that the items may be more intelligibly compared among themselves, or with similar items in other cases.

Jan 1, 1878

William Andrews Clark, former United States senator from Montana, died at his home in New York on March 2, at the age of 86, after a brief illness due to pneumonia. He was the last of the three great Montana mining magnates, Clark, Daly and Heinze. He was born in Connellsville, Pa., on Jan. 8, 1839, and in 1863 arrived in Bannock, Ida., with only five dollars, after a journey of 65 days. On reaching Idaho, he became successively a miner, teamster, machinist, railway builder, mine owner, capitalist and, in his more recent years, philanthropist and art collector.

Jan 1, 1925

By W. C. Hazen, A. V. Henrickson

URANIUM plant operations of the Kerr-McGee Oil Industries at Shiprock, N. M., began in December 1954. As originally designed, the plant treated Plateau carnotite ores by the acid cure process, which dissolved both uranium and vanadium minerals. After 16 hr of acid curing, the ore was conveyed to an agitator and leached for 2 hr in acid liquor at a pH of 1.0. The leach pulp was then separated at 100 mesh in a classifier, the sands continuing through a washing classifier circuit and the slimes going to a countercurrent decantation system of four thickeners.

Jan 9, 1957

By Lawrence Adler

MINE hoist ropes have hitherto been selected by successive approximation, a process both tedious and inexact. The proposed expression is a readily solved synthesis of existing data and the following standard equation:1 [ ] For convenience, a glossary of all terms appears on page 564. Since rope weight (Wr) and bending load (B) are functions of unit rope weight (Wo), which in turn is a function of rope strength (T), W, and B can be expressed in terms of T. Wr as a Function of T: A study of the curve in Fig. 1, unit rope weight vs strength, yields Eq. 2:

Jan 5, 1957

Lake Superior Iron Ore Association, 3100 East 45th St , Cleveland, Ohio W L Tinker, Secretary This Association does not issue scientific technical bulletins, strictly speaking, but statements, etc , are published containing information of interest to mining engineers and geologists To show the type of information published, mention may be made of material issued in 1931: 1 Directory of mine operators and statistical data. 2 A bulletin, Distribution of Lake Superior iron ores, also Eastern and foreign ore 3 A booklet, Analyses of Lake Superior iron ores, season 1931 These publications, or information on others may be had by addressing the above

Jan 1, 1933

By R. Van A. Mills

ONE of the most important problems facing the petroleum industry is the profitable recovery of oil that is left underground by the ordinary methods of production. It is true that vast quantities of oil are being recovered from fields previously considered depleted by the pressure restoration method, the most widely applicable -and most successful means of obtaining greater recoveries that has thus far been, developed. But notwithstanding the progress that is being made in the field applica¬tion of this method there is urgent need for a better understanding of the fundamental principles that are involved. To meet this need the Petro¬leum Experiment Station of the U. S. Bureau of Mines at Bartlesville, Okla., during the past two years has conducted a series of intensive laboratory and field investigations. The larger part of the work has been carried on in the laboratory to supply the much needed information upon fundamental principles, information which few if any of the oil companies are in a position to supply for themselves. In all of this work the Bureau is endeavoring to correlate the results of laboratory investigations with those in the field, using the results of one to guide or check the other. This paper is primarily a progress report, briefly outlining the Bureau's methods of study, the laboratory and equipment in use, the preliminary problems that had to be solved in order to attack the major problems at hand, the methods of attacking some of the major problems, and some of the results of the investigations to date.

Jan 1, 1928

The following list comprises the names of those persons who became. members during the period Oct. 10, 1919, to Nov. 10, 1919. ABELL, 0. J., Pres. & Treas., Abell-Howe Co., 332 South Michigan Ave.; Chicago, Ill. ADAMI, ARTHUR E., Asst. Prof. of Min. Engrg., Montana State School of Mines,Butte, Mont. BASSETT, R. H Chief Engr., Hanna Ore Min. Co., Hibbing, Minn. BOZA, HECTOR J., Cons. Engr., Boza Aizcorbe Hermanos, Box 106, Lima, Peru. BROWN, HAROLD P., Cons. Concrete Engr 120 Liberty St., New York, N. Y. BUCHANAN, W. A Mgr., Meteor Mine, Slocan City, B. C., Canada. CAMERON, JAMES A Supt., Ellsworth Collieries Co., Ellsworth Pa. CARPENTER, CRANSTON HOWE, Electro-Met. Engr., General Engrg. Division, Westinghouse Electric & Mfg. Co., East Pittsburgh, Pa. CASTLETON, GEORGE T Assayer, Custom Office, Box 122, Eureka, Utah. CHAFFIN, C. E., Eastern Mgr., General Engineering Co., 120 Broadway, New York-, N. Y. CLARK, WALTER R., Wks. Mgr., Bridgeport Brass Co., 1875 Park Ave., Bridgeport, Conn. CLARKE, ERNEST E., Min. Engr., Vinegar Hill Zinc Co., 419 S. Court St., Platteville, Wis. COOLIDGE, E. B., Mgr., Spotted Horse Mine, St. Paul Montana Min. Co., Maiden, Mont. CORTELYOU, ARTHUR P., Resident Mgr., Potrero Min Co. Mocorito, Sinaloa, Mexico. COTTINGHAM, KENNETH, Pet. Engr., Halter & Robitaille Delmonico Bldg.,Fifth Ave. & 44th St., New York, N. Y. CREW, J. A Mgr., Research Dept., Pittsburgh Steel Co., Monessen, Pa. CUMMINGS, LISTER M., Efficiency Engr., Copper Queen Branch, Phelps-Dodge Corpn., Box 1539, Bisbee, Ariz. DANFORTH, GEORGE L., JR., Asst. Gen'l Supt., Illinois Steel Co., South Works, South Chicago, Ill.

Jan 12, 1919

By Alexander L. Field

IN a previous paper,' the experimental methods used and some of the results obtained in an extensive investigation of steels containing zirconium were described. The present paper considers in greater detail one of the most interesting of these effects, namely, the elimination of " red shortness" and the occurrence in steel of a compound of zirconium and sulfur. A consideration of the actual percentages of zirconium, manganese, and sulfur in numerous steels in the light of behavior during rolling has led to new conclusions of the most practical import regarding the reciprocal relationships of these elements. The microscopic examination of high-sulfur steels containing zirconium has also been productive of interesting results. Before discussing the experimental data in question, it may be stated, briefly, that the rettetion between zirconium and sulfur in molten steel may be represented by the simple equation, Zr + 25 = ZrS², and that the zirconium sulfide thus formed occurs in the finished steel in the form of gray-colored inclusions, closely resembling manganese sulfide and, like the latter, exhibiting plasticity at rolling temperatures. Molten steel containing zirconium retains such a negligibly small amount of oxygen in solution that the foregoing reaction goes to completion. Hot-rolling Properties of High-sulfur Steels with and without Zirconium The chemical composition of twenty-eight steel ingots embracing eleven heats made in a basic-lined electric furnace is shown in Table 1. The practice followed in the manufacture of these high-sulfur steels was described in the previous paper. Table 1 also gives the behavior of the

Jan 1, 1924