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By J. B. Clark

An exploratory study of the 60 wt pct Mg and 80 wt pct Mg sections of the solid constitution in the magnesium-rich region of the Mg-Al-Ca-Zn system was undertaken. The objective of the investigation was to determine the general configuration of the phase fields with respect to the magnesium solid solution in this complex system. The 335°C (635°F) tetrahedron was selected for study because the solid constitutions of the bounding ternary systems—Mg-Al-Zn,1 Mg-A1-Ca,2 Mg-Ca-zn3—were well known and, at least in these ternary systems, diffusion was rapid enough at 335°C for equilibrium to be reached fairly rapidly. Metallography and powder X-ray diffraction were selected as the best corroboratory methods for determining the solid phase equilibria. A total of forty-six quaternary alloys on the 60 wt Mg and 80 wt Mg sections were prepared, annealed to equilibrium at 335°C, and the phases present identified. Singly sublimed (99.99 pct) magnesium, electrolytic (99.99 pct) zinc, high-purity (99.99 pct) aluminum, and USP calcium were alloyed in graphite crucibles under a chloride flux and chill cast into a split graphite mold. Alloy samples were sealed under argon in Pyrex vials and annealed at 335°C ± 1/2° for a minimum of 500 hr. At the conclusion of the anneal, the alloy samples were quenched rapidly in ice water. Standard metallographic procedures for magnesium alloys were used. Powder X-ray diffraction patterns were taken on a G. E. Camera with a diameter of 14.32 cm using nickel filtered copper radiation. The phase equilibria in the 60 wt pct Mg section of the 335°C (635°F) tetrahedron is shown in Fig. 1. The complex equilibria in the zinc-rich region were not accurately determined and are shown only tentatively with dotted lines. The equilibria of the three bounding ternary 335°C sections from pure magnesium to 60 wt pct Mg are also shown as though folded away from the tetrahedron. The 80 wt pct Mg section has the same configuration of phase fields as that shown in Fig. 1. Thus it is reasonable to conclude that in higher magnesium sections, the same relative configuration of phase fields is maintained though the relative proportions of the individual phase fields may change slightly as the magnesium solid solution is approached. Note that all the ternary phases present in these ternary diagrams enter into the quaternary equilibria with the exception of the phase of the Mg-Al-Zn system which becomes unstable with the addition of as little as 1/2 pct Ca. No quaternary intermetallic phases were found. No liquid phase was detected in any of the quaternary alloys annealed at 335°C suggesting that if a quaternary eu-tectic exists, it must lie between 335°C and 339°C, the temperature of the ternary eutectic in the Mg-Al-Zn system.

Jan 1, 1962

By Bauer, Alan

In considering blasting it is necessary to consider the drilling and explosives since one is generally concerned with the total cost of muck of a certain size in the pit or through the crusher. To get a current idea of the drilling situation in open pit mines plotted in Fig. 1 are the drilling costs per ton of material vs. hole diameter for rotary drill holes in large limestone, iron ore and taconite operations. The exception is the 2-in. diam hole which was drilled with a percussion drill in limestone.

Jan 1, 1968

By K. M. Rolls, J. Wulff, D. A. Colling

Solid-solution alloys of the Ta- Ti system containing up to 70 at. pct Ti were melted and fabricated into wire. Steady magnetic-field measurements of cold-worked wires at 4.2°K indicate that the resistive critical field increases smoothly with increasing titanium, reaching a maximum of 93 kG (J = 1 amp per sq cm) for a composition of about 50 at. pct Ti. The composition dependence of the resistive critical field indicates it is largely paramagnetically limited for alloys containing more than 35 at. pct Ti. For cold-worked wires the value of the critical current density, Jc , was found to be insensitive to composition changes for compositions in excess of 20 at. pct Ti. It was observed that Jc could be increased by final-size heat treatment at 400°C without altering the value of- the resistive critical field. Experimental data are used to calculate the electronic specific-heat coefficient and the "upper critical field" for the alloys studied. THE effect and importance of metallurgical structure on superconducting properties have been summarized by Livingston and Schadler.1 Specific work on solid-solution alloys such as Nb-zr2-7 and Nb-Ti5-7 have shown that critical current density (Jc) and superconducting transition temperature are structure-sensitive. Berlincourt et al.6,8,9 in their studies of transition-metal alloys find that Ta-Ti alloys remain superconducting at fields comparable to Nb-Ti alloys. 6,8 Transverse critical current tests of a Ta-10 at. pct Ti alloy10 and longitudinal critical current tests of a Ta-25 at. pct Ti alloy1' indicate that such alloys are capable of carrying high currents at intermediate fields (-40 kG). The work reported in the present paper was undertaken to explore the superconducting properties of further compositions in the Ta-Ti alloy system as well as the structure sensitivity of the superconducting properties. I) EXPERIMENTAL PROCEDURE Alloys were prepared by melting tantalum (Fansteel Metallurgical Corp., 99.96 pct purity) and iodide, crystal bar titanium (Foote Mineral Co., 99.92 pct purity) mixtures in an arc furnace on a water-cooled copper hearth using a tungsten electrode. Melting was accomplished in a purified, gettered argon atmosphere at pressures from 250 to 400 Torr. Each alloy was turned and remelted fourteen times to assure complete mixing of tantalum and titanium. Ex- cessive coring in the cast samples was, nevertheless, observed. This was somewhat reduced by annealing in vacuo at 1000°C for 13 hr. The ingots were then machined to 0.250 in. diam, jacketed in Type 304 stainless-steel tubing, and swaged to 0.140 in. diam. They were then drawn to 0.010-in.-diam wire. Alloys containing up to 70 at. pct Ti were readily cold-drawn to wire in this manner. Later experiments showed that oxygen additions up to -3000 ppm could also be cold-worked into wire. Test samples for superconductivity measurements in the 2-in, air-core Bitter solenoids of the M.I.T. National Magnet Laboratory were prepared from 10-in. lengths of 0.010-in.-diam wire, cleaned of residual wire-drawing lubricant. Current contacts were made by clamping clean copper tubing over both No. 18 current lead wire and the ultrasonically indium-tinned ends of the specimen wire.12 Potential leads of No. 32 copper wire were connected to the specimen by ultrasonic soldering in an indium bath. The potential lead separation was about 4 cm, corresponding to the circumference of the Bakelite rod to which the wire was affixed with half-mil Teflon tape. The final specimen configuration is shown in Fig. 1. Specimens were lowered into a liquid helium bath (4.2oK) in a double solenoid dewar and positioned so that the maximum magnetic field was oriented transverse to the wire axis of the gage section. Measurements were made by passing a current through the specimen at a preset solenoidal magnetic field. The current was increased until a 1-pv potential difference appeared across the gage section (1/4 µv per cm). At low magnetic fields, however, it was not possible to use this criterion because power-dissipation difficul-

Jan 1, 1967

By P. Barnes

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 he 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, 1879

Electro-mechanical actuator, self-protected for mechanical and electrical overload, is developed by RACO. Tubular housing consists of squirrel cage motor with hollow rotor shaft and inner threads in the rotor. Features stroke distance of 2-72 in. and wide range of trust (20 lb-10 tons). (100) Agglomeration systems, offered by Ferro-Tech, incorporate pelletizing, briquetting and extrusion systems to agglomerate materials too fine to convey, load or feed to a process. Equipment includes disc and drum pelletizers, briquetter presses, compactors, extruders, pugmills and mixers, dryers, coolers, feeders and conveyors. (101)

Jan 9, 1973

(The following list contains the names of those members of the Institute of whose connection with military service we have only recently become acquainted; it also includes the names of a few who have recently been promoted or transferred. A complete list was published in the Year Book, issued as a supplement of the Bulletin for March, 1918.) ANDREWS, CLARENCE W., 2d Lieutenant, 12th Batt. Infantry Replacement Regiment. ANDREWS, JOSEPH C., Ordnance Dept., U. S. A. ARLUCK, A. A., Headquarters, 1st Corps of Artillery, A. P. O.. No. 759, A. E. F.

Jan 9, 1918

By J. W. Lewis

This review covers that portion of the area between the Llano mountains and the Red River which lies between Fort Worth and Abilene. The counties and fields included are listed in Tables 1 and 2. During 1929 there was a marked lull in both prospecting and development in this part of Texas. Archer, Coleman, Cooke, Wilbarger and Young were the counties most active. The total gross production of the year was 52,611,000 bbl., 3 per cent. more than for 1928. The production of the Coleman, Cooke-

Jan 1, 1930

By J. Nutting, D. H. Kirkwood

IT is clearly of great metallurgical interest to know the conditions of temperature and gas composition under which different products will form in sulphide roasting. A method of graphically presenting the relevant thermodynamic data will be demonstrated, such that these conditions are readily obtainable. The products of sulphide roasting may be oxide, sulphate, or oxysulphates, and the equilibria between these may be represented in the following way: 2 MSO4 = MOMSO4 + SO3 MO-MSO4 = 2 MO + SO3

Jan 1, 1961

By J. R. Szedon, T. L. Chu, G. A. Gruber

Amorphous adherent filnzs of silicon dioxide have been deposited on silicon substrates by the oxidation of silane at temperatures ranging from 650 to 1050C. Various diluents (argon, nitrogen, hydrogen) were used to suppress the formation of SiO2 in the gas phase. Deposition rates of the oxide were determined over the temperature range in question as functions of' re-actant flow rates. Etch rate studies were used for a cursory comparison of structural properties of deposited and thermally grown oxides. From electrical evaluation of metal-insulator-silicon capacitors it was determined that the interface charge density of deposited films is similar go that of dry-oxygen-grown films in the 850° to 1050 C temperature range. Deposited films exhibit several ionic instability effects which differ in detail from those reported for thermal oxides. Stable passivating films of silicon nitride over deposited oxides appear to be practical for use in silicon planar device fabrication. Such films can be prepared under temperature conditions which have less effect on substrate impurity distributions than in the case of grown oxides. AMORPHOUS silicon dioxide (silica) is compatible with silicon in electrical properties and is the most widely used dielectric in silicon devices at present. Silica films can be prepared by the oxidation of silicon or deposited on silicon or other substrate surfaces by chemical reactions or vacuum techniques. The ability of thermally grown silicon dioxide films to passivate silicon surfaces forms one of the practical bases of the planar device technology. Properly produced and treated films of grown SiO 2 can have low densities of interface charge (-1 X 10" charges per sq cm) and can be stable as regards fast migrating ionic sgecies. 1 To maintain these properties, even with an otherwise hermetically sealed ambient, the Sia layers must be at least l000 A thick. Such thicknesses require oxidation in dry oxygen for periods of 7.8 hr at 900°C or 2 hr at 1000°C. Although oxidation in steam or wet oxygen can reduce these times to 17 and 5 min, the resulting oxides must be annealed to produce acceptable levels of interface charge., Oxidation or annealing involving moderate to high temperatures for extended periods of time can be undesirable. Under some conditions, there can be changes in the distribution of impurities within the underlying substrate. A chemical deposition technique using gaseous am-bients is particularly attractive and flexible for preparing oxide films. With a wide range of deposition rates available, films can be produced under condi- tions of time and temperature less detrimental to impurity distributions in the silicon than in the case of thermal oxidation. The pyrolysis of alkoxysilanes, the hydrolysis of silicon halides, and various modifications of these reactions are most commonly used for the deposition of silica films.3 Silica films obtained in this manner are likely to be contaminated by the by-products of the reaction, organic impurities, or hydrogen halides. The use of the oxidation of silane for the deposition process has been reported recently.4 The deposition of silica films on single-crystal silicon substrates by the oxidation of silane in a gas flow system has been studied in this work. The deposition variables studied were the crystallographic orientation of the substrate surface, the substrate temperature, and the nature of the diluent gas. The electrical charge behavior of Si-SiO2-A1 structures prepared under various conditions was investigated by capacitance-voltage (C-V) measurements of metal-insulator-semiconductor (MIS) capacitors. The experimental approaches and results are discussed in this paper. 1) DEPOSITION OF SILICA FILMS The overall reaction for the oxidation of silane is: The equilibrium constants of this reaction in the temperature range 500° to 1500°K, calculated from the JANAF thermochemical data,= are shown in Fig. 1. In addition to the large equilibrium constants, the oxidation of silane is also kinetically feasible at room temperature and above. However, the strong reactivity of silane toward oxygen tends to promote the nucleation of silica in the gas phase through homogeneous reactions, and the deposition of this silica on the substrate would yield nonadherent material. The formation of silica in the gas phase can be reduced by using low partial pressures of the reactants. Argon, hydrogen, and nitrogen were used as diluents in this work. 1.1) Experimental. The deposition of silica films by the oxidation of silane was carried out in a gas flow system using an apparatus shown schematically in Fig. 2. Appropriate flow meters and valves were used to control the flow of various reactants, i.e., argon, hydrogen, nitrogen, oxygen, and silane. Semiconductor-grade silane, argon of 99.999 pct minimum purity, oxygen of 99.95 pct minimum purity, and nitrogen of 99.997 pct minimum purity, all purchased from the Matheson Co., were used without further purification. In several instances, a silicon nitride film was deposited over the silica film. This was achieved by the nitridation of silane with ammonia using anhydrous ammonia of better than 99.99 pct purity supplied by the Matheson CO.' The reactant mixture of the desired composition was passed through a Millipore filter into a horizontal water-cooled fused silica tube of 55 mm

Jan 1, 1969

By C. T. Malcomson

An elaborate series of experiments has been conducted during the past three years at Irvington, N. J., which has resulted in the perfection of a process for the manufacture of smokeless fuel from high-volatile coals, and for the recovery and refinement of the coal-tar products derived therefrom. These experiments have been financed by Messrs. Blair & Co., of New York, and were conducted under the direction of Charles H. Smith, a member of this Institute, and the inventor of the process. The low-temperature distillation of coal has interested investigators for many years. Sporadic attempts have been made to solve the mechanical problems, but until the Smith process was developed, they were not carried to conclusions of economic value. The present coal shortage and the increasing demand for smokeless fuels make this subject one of timely interest. DescRiption of Plant The following equipment was installed and operated during the experimental period: Four horizontal and two vertical units of commercial size for the low-temperature distillation of the coal; two vertical, two horizontal, and two inclined benches for distillation of the briquets at medium and higher temperatures; presses and auxiliary equipment necessary for making briquets; and a complete byproduct recovery and tar-refining plant. This commercial equipment is provided with gas and electric meters, pyrometers and other apparatus for recording accurately the results of all experiments. There is, in addition to the commercial equipment, a complete chemical laboratory with distillation and recovery apparatus, including facilities far refining and cracking the tar and measuring the yields and calorific value of the gas. This apparatus makes possible a study on a small scale, of the various problems involved in the process. Description of Process Mr. Smith's experiments have resulted in the production on a commercial scale of: 1. A fuel, called Carbocoal, which, for convenience in handling, is prepared in briquet form.

Jan 1, 1920

By C. Laird, C. E. Feltner

IN previous workif2 we have shown that the steady state cyclic stress response of pure copper tested in the low cycle fatigue range was determined only by the plastic strain amplitude and the test temperature. hus, copper, at any given temperature, has a unique cyclic stress-strain curve independent of prior history. Cu-7.5 wt pct Al, however, showed a stress response for a given plastic strain amplitude and temperature which depended sensitively on prior history. From this work we predicted that all wavy slip mode materials, typified by copper, would have a unique cyclic stress-strain curve; whereas all planar slip mode materials, typified by Cu-7.5 pct Al, would not. This prediction has now been tested for a number of materials of widely varying crystal structure and slip character. Wavy slip mode materials studied include: Fe. Al, Cd, disordered FeCo-V, and Cu-3 pct Co (quenched and aged). Planar slip mode materials investigated include: Fe-3 pct Si, ordered FeCo-V, disordered Ni3Mn, ordered Ni3Mn, and Zn. The treatment and properties of these materials are listed in Table I. Cyclic stress-strain curves were determined by controlled plastic strain tests (see Ref. 1 for details) at room temperature for all materials in both the initially annealed and cold worked conditions. The results obtained for iron and Fe-3 pct Si are typical of wavy and planar slip mode materials, respectively. The cyclic stress-strain curves for these materials are shown in Fig. 1 and it can be seen that iron has a unique cyclic stress strain curve while Fe-3 pct Si does not. Aluminum, Cu-3 pct Co, and disordered FeCo-V showed a behavior like that for iron, while Ni3Mn in both the disordered and ordered condition behaved in the same manner as Fe-3 pct Si. These results therefore support the general conclusion drawn in Refs. 1 and 2 that. for wavy slip mode materials, a cyclic mechanical equation of slate it =t.(hcp, i. T) is approximated in which the satura-

Jan 1, 1970

By J. A. Herbst, K. Rajamani, M. Siddique

This paper presents an investigation of the accuracy of population balance model predictions for ball mill scale-up. Experiments performed in 25.4 x 29.2 cm (10 x 11.5) batch mill are used to estimate linear grinding rate parameters that, in turn are scaled according to specific power draft to predict performance in 381 x 292 mm (15 x 11.5 in.) and 762 x 457 mm (30 x 18 in.) batch and continuous ball mills, respectively. Results are presented for wet and dry grinding of two homogeneous solids, limestone (soft) and quartz (hard), and one heterogeneous solid, a complex molybdenite ore. In all cases good agreement between predicted and experimental product size distributions was obtained.

Jan 1, 1983

By Reed S. C. Rogers, Robin P. Gardner, Kuruvilla Verghese

The development and use of short-lived radioactive tracer methods for the onstream determination of residence time distributions in large-scale ball mills is described. Tests are reported on a pilot-plant ball mill with 0.43 m diameter and 0.86 m length and on an industrial mill with 1.83 m diameter and 2.74 m length. Tests with different tracer feed sizes indicate that the residence time distributions on both mills are independent of charge particle size. Similar tests are planned for a large ball mill of 4.57 m diameter and 9.30 m length. No safety problems were encountered in these tests and none are anticipated in tests of the larger mill.

Jan 1, 1981

By W. L. Zeigler

The gravity concentrator of the Heela Mining Co. was originally constructed in 1888 by the Milwaukee Mining Co., which was operating the Gem of the Mountains mine. It was purchased by the Hecla Mining Co. in 1900, and placed in operation 2 years later. At that time the capacity was only about 200 tons a day, but many additions and changes in equipment have been made so that the present capacity is about 800 tons. One of the outstanding improvements made was the substitution of Callow flotation cells for vanners, which occurred in 1915. The recent building of a flotation plant for treating jig tailings, and the construction of a modern surface plant at the mine, following the

Jan 1, 1928

By W. Rostoker, S. A. Spachner

FOLLOWING the discovery of the w transition phase in certain titanium-chromium alloys by Frost, Parris, Doig, and Schwartz, much interest has centered on the alloys in which this phase is found and its mode of precipitation. The w phase has been found in alloys of Ti-Cr, Ti-Fe, Ti-Mn, Ti-MO,2 and Ti-v.3 The temperature-time-transformation characteristics have, as yet, not been determined for most of these. In this study, such transformation characteristics have been investigated for two heat-treatable titanium alloys known to exhibit transition phase phenomena. The alloys chosen, Ti-8Cr and Ti-13M0, are representative of two classes of binary equilibrium systems. In the

Jan 1, 1959

By Ned Kuenhold

AN equipment manufacturer swallows a bitter pill when he sees his machinery improperly in- stalled and not used to the full potential. This frequently happens with vibrating screens. Screens can be classified according to the path of vibration imparted to the screen surface. On this basis there are: 1) vertical circle or modified circle throw, 2) horizontal circle or modified circle throw, 3) vertical linear reciprocation, 4) tilted linear reciprocation, and 5) horizontal linear reciprocation. The most versatile vibration for medium to coarse sizing is generally conceded to be the vertical circle produced by an eccentric or unbalanced shaft, but other types of vibration may be more suitable for certain screening operations, particularly in the finer sizes.

Jan 6, 1957

M. A. Hanna is investigating a nickel prospect near Riddle, Ore. Drilling is under way and a prospect shaft is being put down to obtain samples for metallurgical test work. The deposit is favorably situated for open pit mining. The property had been drilled previously by the USGS and by Freeport Sulphur Co. A $75,000 laboratory pilot plant will begin operations this year to determine if economic beneficiation of a deposit of low grade iron ore, being examined by M. A. Hanna in the Iron River, Mich., district, is possible. Three miles east of Randville 2560 acres of land have been acquired, and drilled, over the last 2 years. The ore is reported to be 34 pat Fe.

Jan 6, 1951

By L. D. Jaffe, W. P. Clancy, D. C. Buffum

Many earlier workers have suggested that the temper brittleness of steel is associated with the presence of carbon or nitrogen. Nevertheless, no investigations on the effect of removal of these elements upon susceptibility to temper brittleness have been published. It was therefore decided to determine whether temper brittleness would develop in an iron alloy ...__, ing very little carbon and nitrogen. The alloy, in the form of a 10-lb ingot, was prepared by melting purified materials under . argon. Its composition, in per cent, was: This analysis, except for carbon content, is within the specified range for SAE 3140, which has been demonstrated by previous work at this laboratory2 to be markedly susceptible to

Jan 1, 1950

By W. L. Zeigler

THE gravity concentrator of the Hecla Mining Co. was originally constructed in 1888 by the Milwaukee Mining Co., which was operating the Gem of the Mountains mine. It was purchased by the Hecla Mining Co. in 1900, and placed in operation 2 years later. At that time [ ] the capacity was only about 200 tons a day, but many additions and changes in equipment have been made so that the present capacity is about 800 tons. One of the outstanding improvements made was the substitution of Callow flotation cells for vanners, which occurred in 1915. The recent building of a flotation plant for treating jig tailings, and the construction of a modern surface plant at the mine, following the

Jan 1, 1928

By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 1 1/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude. The primary thought at the time millisecond de- lays were introduced was to investigate the results on rock breakage by firing a line of holes in a quarry face.so that charges in adjacent holes would not be detonated simultaneously. This could not be accomplished satisfactorily with regular delays. The time interval between successive periods of $5 to 1 sec was sufficient to permit considerable movement of the burden. If the burden of one hole was reduced to a great extent by the firing of an adjacent hole, the firing of the hole with the reduced burden would likely reveal this lack of confinement by a terrific report and wild throw of rock.

Jan 1, 1950