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By David L. Holt, Walter A. Backofen, Anwar-uI Karim

Specimens of a hydrided Mg-0.5 Zr alloy were strained in tension at 500°C and constant rates of 2 x10-3 5 x 10-3, and 2 X 10" min-1. Hydride-denuded zones formed at grain boundaries normal to the tensile-stress direction as a result of magnesium transport during difusional flow. The width of the zones could be measured and the measurement used for calculating the diffusional component of the imposed tensile strain. The strain from diffusional flow was found to increase with imposed strain at a diminishing rate, tending to saturate at approximately 12 pct. Strain rate sensitivity of flow stress was low. The apparent non Newtonian character of the diffusional flow is attributed to a non Newtonian process acting in parallel with it which could be boundary shear. Fracture grows out of voids that form in the denuded zones. DEFORMATION of a grain by diffusion of atoms from boundaries stressed in compression to boundaries stressed in tension is Newtonian viscous,1-3 and evidence has accumulated in recent years that such a process may be responsible for the high strain-rate sensitivity of the flow stress of super-plastic alloys.4"7 One piece of evidence is that experimental stress: strain-rate relationships can be quantitatively explained.5-7 There is also metallo-graphic evidence of diffusional flow in superplas-ticity, but in a limited amount. The formation of striated bands on the surface of superplastically deformed specimens has been attributed to diffusional flow.5"7 The basis of that attribution came from experiments on a coarse-grained, nonsuperplastic and hydrided Mg-½ wt pct Zr alloy which formed hydride-denuded, light etching zones at tension-stressed boundaries when strained in tension at 270?C.6 The origin of these zones had already been traced to the diffusional flow of magnesium atoms to the boundaries.' The particular observations in the more recent work were of striated-band formation on the surface and denuded-zone formation internally, with both the bands and zones having the same width and appearing at tension-stressed boundaries. It was argued that the bands were a surface manifestation of the zones and hence of diffusional flow. Of course in superplastic alloys which do not contain internal metallographic "markers", the surface bands can be the only metallographic indication. In the present work, denuded-zone formation was utilized, as it has been by others,9-11 to extend the observations of diffusional flow and to measure the strain, ed, resulting from it. Grain size had to be large to measure ed with accuracy. The grain size chosen for this study was -30 , and with that a strain of 10 pct from diffusional flow produces a denuded zone only 3 µ in width. The large grain size naturally precludes superplasticity. The observations of diffusional flow were complemented by determining the strain from the other operative deformation modes: slip, e,, and grain boundary shear, egb. An incremental specimen extension is the sum of increments from slip, and grain boundary shear as well as diffusional flow. Division by a common length is required to convert to strain. If this length is taken as the initial specimen length, then imposed engineering strain, e, is given in terms of the component engineering strains by e = ed + es + egb [1] Stress:strain-rate relationships are determined by the way in which this "strain balance" is made up. EXPERIMENTAL Material. Zirconium hydride markers were introduced into the Mg-0.5Zr alloy by annealing in hydrogen at 450°C for 30 min. The hydride concentration was particularly high at zirconium rich stringers, which was fortunate in that the transverse boundaries at which denuded zones form lie perpendicular to the stringers. Grain size after annealing was 30 µ. Photomicrographs of unstrained and strained material are shown in Fig. 1. Procedure. Specimens were strained in tension with an Instron machine at crosshead velocities of either 2 x 10"3, 5 x X or 1 x 10-2 in. min-'. Specimen length and diameter were 1.0 and 0.2 in., respectively, so that initial strain rates in tests at constant crosshead speed were 2 x 10"3, 5 x X and 1 X l0-2 min-1. Tests were made at 500°C which is a compromise temperature at which diffusional flow is still measurable but grain growth is not active enough to interfere with metallographic measurements. The tests were made in a hydrogen atmosphere. Strain Balance. An equation additional to [I] is eg = ed + es [2] where eg is strain measured from grain elongation. Measurement was made of ed, eg, and, of course, e, which enabled all the strains in Eq. [I] to be determined. For this purpose, strained specimens were sectioned longitudinally, polished, and etched. The strain from diffusional flow, ed, was computed by measuring on photomicrographs the width in the tensile direction of denuded zones at either end of a grain XI, X2, adding them, and dividing by twice the initial longitudinal grain dimension L0, Fig. 2. Reported values are the results of measurements on seventy randomly selected grains; 95 pct confidence limits on ed were +1.5 pct strain. To measure eg, the maximum length, L, and the maximum width, W,

Jan 1, 1970

By Thomas C. Wilder

ALTHOUGH there is an abundance of thermodynamic information available in the literature today, no experimental data on the standard molar properties of formation of zinc oxide have ever been reported for the temperature range 419.5" to 908°C. This is the temperature range for which zinc metal is a liquid. so that the formation reaction is: Data have been reported for Reaction [I] where zinc is a solid or a gas. Maier. Parks, and nderson' measured the electromotive force of the cell: in order to obtain the free energy of the reaction: over a limited temperature range. With the known properties of H2O, those of ZnO were calculated. These workers found that t;j of ZnO is -75,930 ± 150 cal per gfw and Mtf is-83,000 300 cal per gfw at 25°C. akolkin made similar measurements to obtain ilF7 and AH; of -75,870 and -82,540 cal per dw respectively at the same temperature. Truesdale and arirlg and Kitchener and 1gnatowicz4 measured the equilibrium of the reactions: respectively, in order to determine Ff of ZnO from the known values of CO, CO2, and H/X The thermodynamic properties of ZnO, presumably taken from the above investigations, are tabulated by Kubaschewski and vans' and Wicks and Block" The latter reference also gives values for the range where zinc is a liquid. These numbers are probably acquired from the known extremities of the range plus Cp data of the components. In the present work the electromotive force of the cell: was measured in order to calculate the properties of ZnO from the well known values of NiO for the temperature range where zinc is a liquid. In Cell [B] the cathode reaction is: and at the anode: The overall reaction is: for which the free energy change is: where is the electromotive force in volts of cell [B] after correction for the Pt-Ta thermocouple. The standard molar free energy of formation of NiO is very well known as a function of temperature. Kiukkola and agner's data are used in most tabulations. The error is probably less than I00 cal per gfw, The latter authors were the first to use solid mixed oxide electrolytes in galvanic cells. Their work with NiO and other oxides was performed with cells similar to Cell [B] using a variety of reference electrodes of fixed oxygen potential. There may be a small composition range for which either NiO, ZnO or both exist. If nonstoichiometry does exist for these oxides, then the properties described herein are those for the metal saturated compositions. The simple cell design was the same as described elsewheres except that the molten metal electrode was about 125 g of pure zinc including a small (0.25 to 0.50 g) amount of ZnO. The mixture of pure nickel and NiO powders making up the reference electrode was contained in a tube of the ZrOl + CaO electrolyte which was immersed in the molten zinc. A platinum contact was made to the reference electrode; tantalum to the zinc. A refractory cement plug was necessary at the open end of the electrolyte tube in order to prevent zinc vapor from contaminating the reference electrode. Experimental details such as the vessel containing the cell, furnace, temperature control and measurement, and electromotive force determinations of the cell have all been outlined previously. The temperature was varied randomly in the range between the freezing and boiling points of zinc. After each temperature change, time was allowed for the drift at the new temperature to be less than +;"c whereupon a series of three cell readings was taken at least 10

Jan 1, 1970

STANFORD UNIVERSITY, CALIFORNIA Our activities for the year 1918-19 have closed with the coming of summer. It has been a most successful year in many respects, especially in the reorganization necessary after the war conditions had passed. An INITIATION SCENE AT STANFORD UNIVERSITY. "old-days" initiation was held on the Stanford campus by the Society a few weeks ago. The accompanying picture explains some of what took place when the following men were taken into the membership: W. P. Winham, Salinas, Calif. ; T. L. Wark, Long Beach, Calif.; P. L. Henderson, Greeley, Colo.; T. E. Bassett, Palo Alto, Calif.; and R. G. Wheelton, Long Beach, Calif. CHAS. A. DOBBEL, Secretary.

Jan 8, 1919

By N. A. Gokcen

EQUILIBRIA in the reactions between gases and liquid metals have been the subject of many interesting investigations. The experimental realization of true equilibrium, however, is questionable in certain cases due to the lack of conclusive studies in reaction rates. It -will be shown here that a systematic interpretation of rate studies with the analysis of prevailing experimental conditions leads to valuable practical information. The reactions of particular interest are: H2(g) +S(inFe) - H2S(g) [1] H2(g) +O (inFe) =H2O(g) [21 2H2(g) + SiO2(s) = 2H2O(g) + - (inFe) [3] The usual and perhaps the most convenient method of investigation may be illustrated with reaction 1. A stream of gas mixture consisting of H2 + H2S is passed over or bubbled through the liquid metal at constant temperature. The ratio of H2S/H2 in the entrant mixture is fixed in each experimental run, and, therefore, the composition of melt varies until the establishment of equilibrium. The purpose of this paper is to derive a formula expressing the minimum time required for the establishment of equilibrium and to compare the calculated values from such a formula with the available data. Equations Reaction 1 is used for the purpose of illustrating the derivation. Let E represent the equilibrium and X the nonequilibrium sulphur in weight percent at any time t in minutes. For the sake of simplicity, it is first assumed that E > X although the results are of general applicability without restriction. It has been shown by Morris and Williams' that within a difference of 1 pct S or less, i.e., E-X5 1.00, the value of K'1 = Ph2s/Ph2.S% is very nearly constant. The maximum ratio of available Ph2s/Ph2 = H,S/H,, from which sulphur can be absorbed by metal, is equal to H2S/H2 in equilibrium with E (which equals H2S/H2 in the entrant gas), minus H,S/H, in equilibrium with X. Thus: Available H2S/H2 = EK'1 - XK'1 [4] Eq. 4 expresses that sulphur can be absorbed by metal from the H2S/H2 in the entrant gas until the gas leaving the metal assumes a value of H2S/H2 which is in equilibrium with the dissolved sulphur X at that time. H,S constitutes up to approximately 1 pct of the gas mixture. Its disassociation into H2 and SL is about 1 pct at 1600°C, hence, the H2S/H2 impinging on the surface of metal is very close to that in the entrant gas. The rate of flow of hydrogen entering the reaction chamber is kept constant experi-

Jan 1, 1954

By B. H. Caudle, L. G. Loncarie

Pilot flooding is one method of evaluating a proposed secondary recovery project. However, the amount and rate of oil recovery from an unconfined pilot area is not usually the same as from an equal area in a large-scale flood. This is true because fluids are free to move across the boundary of a pilot area. The result is that some of the oil produced in a pilot flood may come from outside the designated area and some of the displaced oil may leave the pilot area completely. This paper presents the results of fluid-flow model studies on a five-spot pilot flood. Mobility ratios between 0.1 and to have been studied. The effects of changing the ratio of injection to withdrawal rates are shown. INTRODUCTION A small-scale field test, or pilot flood, is an accepted method for evaluating the applicability of a secondary recovery operation and the economic potential of that operation for a reservoir. The pilot flood is carried on in the same manner, with the same injected materials and at the same pressures as would be used were the secondary recovery program to be expanded to a larger area of the field or to the entire field. If the reservoir fluid and reservoir rock properties are the same in the pilot area as in the rest of the reservoir, the production, injection and other pertinent data associated with the pilot test will represent and measure what should be expected from a full-scale development of this secondary recovery program. There is one major exception which, unfortunately, has been overlooked by many and which has been awaiting quantitative definition. This is the sweep-out pattern the reservoir engineer must use in interpreting the pilot flood and in extrapolating it to the full-scale development. The sweep-out area in a pilot flood is not contained within the five-spot pattern. Further, there is oil flow into and/or out of the five-spot during a pilot test. Thus, production data from pilots must be interpreted with this different flow system and sweep pattern in mind. We have studied the sweep-out pattern that will exist for some conditions of operation of pilot flooding a single five-spot (four injection wells and one producer). In our study, reported here, we have assumed that the reservoir is relatively homogeneous and of uniform thickness in the pilot area. The results of this study en-able the engineer to predict the recovery, injection requirements and project life for a full-scale operation from the pilot flooding data. The effects of various injection to withdrawal-rate ratios and mobility ratios in a relatively gas-free (10 per cent pore volume or less) system are shown. Experimental Method The technique used in this study was the same as that for the X-ray shadowgraph studies of sweep-out pattern efficiencies.' The model of the pilot and surrounding area was made from a uniform packing of round-grain sand consolidated with an epoxy resin. Fig. 1 shows the relation between the model and the pilot area. Only one-eighth of the pilot area had to be represented in the model because we assumed equal injec-

By A. V. Deforest, A. R. Anderson, C. W. MacGregor

ONE of the important problems in the design of structures and machine parts subjected to rapidly applied loads is the determination of the strength and ductility of the material itself under such conditions. Realizing the need for such information, many investigations have been carried out in the past. Most of these experiments have been made using notched bars in bending either with the Charpy or Izod impact machine. While yielding valuable data on the effect of notches in the energy absorption of the material and on the condition of heat-treatment, this form of test does not lend itself readily to a determination of fundamental stress-strain relations. For this and other reasons, more attention has been paid recently to the tension impact test. An extensive literature already exists on the subject and only those investigations somewhat closely related to the present paper will be mentioned. For a more comprehensive list, the reader is referred to the Symposium on Impact Testing of the A.S.T.M., 1938. The work of Mann,1 Clark and Dätwyler,2 Nádai and Manjoine,3 Winlock and Leiter,4 Deutler,5 and Brinkmann,6 however, deserve especial mention. In most of the previous investigations on the subject, when stress-strain relations were obtained under high rates of loading, it was the common procedure to determine stresses based on the original area and strains based on the original length. Stress-strain curves were then constructed by [P OL, plotting So = Ao as a function of eo = Lo] where A o and Lo refer to the original area and gauge length, respectively. At present there exists a paucity of true stress-strain data in the impact problem. The advantages of constructing so-called true stress-strain curves in order to reveal the fundamental physical properties of the material for the tension test were discussed recently by one of the authors' It was shown that the true physical behavior of the material in the tension test could best be represented [by plotting the average true stress, S = P as a function of e = q' = log o = log Log] where P, A, L, S, e, and q' refer to the load, the cross-sectioned area while the load P is applied, the actual gauge length, the average true stress, the true strain and true reduction in area, respectively. Besides giving a better physical representation, the method has certain additional advantages in that the stress-strain curve so plotted becomes a straight line from the maximum load point to fracture. The construction of such- curves, however, while comparatively simple for the slow rates of loading customarily used in the tension test, presents certain difficulties for tensile impact in that both loads and diameters are required throughout the test. The continuous measurement of test-piece

Jan 1, 1941

By E. I. Larsen, A. S. Doty, F. R. Hensel

The alloy under discussion is a Pig. I shows results of heat-treating tests nickel-silicon bronze and is one of many on two typical nickel-silicon bronze castings age-hardening or precipitation-hardening of the type on which the observations were copper-base alloys. The hardening constituent is a nickel-silicon compound.l The quenching temperature necessary to produce hardening by a subsequent aging treatment is a function of the composition and extends from about 700°C. to 950°C.; the aging temperature range extends from 4000 to 600°C. The work carried out by the authors of this paper was confined to cast alloys having compositions within the ranges of: 1.5 to 3.00 per cent Ni; 0.4 to 0.75 per cent Sj: balance. comer. made. A quenching temperature of 750°C. produces almost as high a hardness on subsequent aging as do quenching temperatures of 850' and 900°C. Several foundries have spent years of active and intelligent effort in trying to control the casting and heat-treating variables of nickel-silicon bronzes and finally gave up the attempts because of the inconsistencies of results.2 This undesirable characteristic was not manifest in the ultimate hardness or conductivity but primarily in tensile strength and ductility, as shown in Table I. The variation in tensile properties was often much greater than that existing on the alloys

Jan 1, 1941

By A. S. Doty, E. I. Larsen, F. R. Hensel

The alloy under discussion is a Pig. I shows results of heat-treating tests nickel-silicon bronze and is one of many on two typical nickel-silicon bronze castings age-hardening or precipitation-hardening of the type on which the observations were copper-base alloys. The hardening constituent is a nickel-silicon compound.l The quenching temperature necessary to produce hardening by a subsequent aging treatment is a function of the composition and extends from about 700°C. to 950°C.; the aging temperature range extends from 4000 to 600°C. The work carried out by the authors of this paper was confined to cast alloys having compositions within the ranges of: 1.5 to 3.00 per cent Ni; 0.4 to 0.75 per cent Sj: balance. comer. made. A quenching temperature of 750°C. produces almost as high a hardness on subsequent aging as do quenching temperatures of 850' and 900°C. Several foundries have spent years of active and intelligent effort in trying to control the casting and heat-treating variables of nickel-silicon bronzes and finally gave up the attempts because of the inconsistencies of results.2 This undesirable characteristic was not manifest in the ultimate hardness or conductivity but primarily in tensile strength and ductility, as shown in Table I. The variation in tensile properties was often much greater than that existing on the alloys

Jan 1, 1941

By Raymond M. Howe

Additional data have been secured on the disintegration of furnace linings and the spalling of stove brick. The first article on the disintegration of furnace linings appears to have been written by John Pattinson in 1876.l The furnace involved was 85 ft. (25.0 m.) higher and 27 ft. (8.2 m.) in diameter at the boshes; after being in blast five years, the top brick became contaminated with carbon and disintegrated. An examination of the lining showed that the discolored, disintegrated brick were in a zone found from 35 to 67 ft. (10.6 to 20.4 m.) above the hearth; immediately below, in a zone extending from 22 to 40 ft. (6.7 to 12.1 m.) above the hearth, the brick were hard and porcelain-like in appearance. Analyses of samples taken from the different sections are given in Table I. The water-soluble portion found in the sample taken 39 ft. (11.8 m.) above the hearth had a composition approximately as follows: silica, 0.50 per cent.; lime, 0.04 per cent.; potash, 0.78 per cent.; soda, 0.20 per cent.; potassium chloride, 6.19 per cent.; moisture, 1.03 per cent.; total, 8.74 per cent. The carbon Table 1.—-Analyses of Samples Taken from Diferent Sections of Furnace . I ii In Iv v Section 67 Section 45 Seotion 39 Section of Original ft Above ft above ft above vitrified Lining Hearth Hearth Hearth Portion Per Cent. per Cent per Cent per cent. per Cent Silica........................... 55.70 55.60 55.67 47.60 37.07, Alumina........................ 35.50 35.40 30.00 26.47 23.18 Ferric oxide..................... 3.00 1.32 0.96 Lime........................... 0.23 0.06 0.17 Magnesia....................... 1.22 0.95 0.86 0.00 Potash......................... 2.60 2.10 5.30 7.54 21.59 Soda.........,.................. 0.45 0.42 1.67 0-76 6.28 Ca1bon ......................... 2.05 3.24 5.97 Carbon dioxide.................................. 2.. 17 Water...................................... 7.70 Water-soluble........................... 8.74

Jan 1, 1920

By Young C. Kim, Francis Martino, Ish Chopra

For the past two and one-half years, various emission control strategies were jointly developed by the University of Arizona and the Homer City Owners to com- ply with the clean air requirements at its Homer City Power Plant. Some of the available options for the SO2 emission control by the Homer City Owners were:l)cleaning of run-of-mine coal,2) scheduling of mining operations at its captive mines, 3) blending the captive mine coal with externally purchased low sulfur coa1,and 4) placing a partial FGD system. This paper describes two specific emission control strategies developed and implemented. These are: 1) production scheduling at the mining face to minimize sulfur variability, and 2) external purchasing of low sulfur coal for further blending. The main objective of this paper is to share our experiences on implementing the developed strategies. This paper emphasizesthe need for proper mine planning on a short-term basis, if the power plant is to meet the desired objective.

Jan 1, 1983

[Chairman ZAY JEFFRIES, Vice-chairman S. SKOWRONSKI, Chairman WILLIAM M, CORSE, Secretary Executive Committee J. R. FREEMAN, JR., Local Section G. E. JOHNSON R. S. ARCHER, Non-ferrous Data Sheets P. D. MERICA EDGAR C. BAIN, Journal Committee L. W. SPRING SAM TOUR, Papers Committee F. L. WOLF H. C. JENNISON, Membership Committee Local Section Committee J. R. FREEMAN, JR., Chairman R. J. ANDERSON, Cincinnati R L. DOWDELL, Minneapolis R. S. WILLIAMS, Boston G. H. CLAMER, Philadelphia W. A. SCHEUCH, Chicago R. F, Woon, New York Papers Committee S. SKOWRONSKI, Chairman F. H. DIx, JR.-Aluminum E. R. DARBY-Bronze C. S. WITH ERELL-Copper H. A. BEDWORTH-Brass W. K. FRANK-BRONZE F. W. HARRIS-Copper R. L. SUHL-Nickel H. M. ST. JOHN--Foundry Metallurgy R. S. DEAN-Theoretical Metallurgy]

Jan 1, 1928

By F. A. Olson, J. S. Cho, M. E. Wadworth

An infrared study of the states of hydration of MgSO4 revealed a hitherto unreported metustable dehydration state in the temperature range just below that of the stable anhydrous salt. Infrared, thermogvavimetric, and X-ray studies indicated that the state had bisulfate and hydroxide characteristics. A formula fitting all of the experimental evidence is hydrogen-bonded Mg(OH)HSO4, or possibly the chemically equivalent 1/2 Mg(HSO4)2. Mg(OH)2 Infrared spectra of the 7, 6, 1, and OH2O states of hydration are given as well as the spectra of the newly found state which is called the bisulfate state in this paper. Thermogvavimetric studies as a function of water-vapor pressure gave an enthalpy value of 16 cal per mole, and 25 eu for the conversion of the bisulfate state to that of the anhydrous salt. The free energies of the transition varied from 1.76 to 0.18 kcal per mole as the transition temperature varied from 279° to 336°C. The bisulfate state is believed to be of importance in catalytic dehydration phenomena using MgSO4 and may be of interest because of properties in sulfating reactions differing from those of the monohydrate. Also, an analogous state may exist as a hydration state of other sulfates. ANHYDROUS magnesium sulfate is a catalyst with a high degree of specificity for the dehydration of secondary alcohols.1'2 The only product obtained at the usual operating temperature range of 360" to 400°C other than the corresponding olefin is water. Thus, the bonding of water to the anhydrous salt as well as an understanding of the hydration states of MgSO4 became of interest in attempting to understand the catalytic mechanism better. In the process of this study using infrared, X-ray, and thermogravimetric analyses a dehydration state not previously reported was found. Proof of its existence, the nature of the state, and its role, if any, in the catalytic mechanism then became of interest. This paper is concerned principally with the first two aspects of this problem. Magnesium sulfate forms many hydrates, of which the monohydrate and heptahydrate (Epsom salts)3 are most important. Other hydrates4 are known with 1-1/4,5 l-1/2, 5 2, 4, 5, 6, and 12 H2O's. The hydrates with 1-1/4, 1-1/2, 2, 4, and 5 HzO's are unstable. The anhydrous salt is very stable thermally and has a strong affinity for water. It can be heated without additional decomposition to about 800°C.' At 900°C noticeable decomposition takes

Jan 1, 1964

By W. S. Pellini, F. N. Rhines

IN many of the otherwise well established alloy phase diagrams the solidus curves (temperatures at which liquid first appears upon melting) have not been located accurately, chiefly because the experimental techniques that have been most popular for determining solidus temperatures have been both cumbersome and subject to large errors. C. E. Homer and H. Plummer1 have described a sensitive and at the same time a very simple technique for locating the solidus curves in a number of alloys of tin. Their method consists simply in noting the temperature at which a specimen of the alloy ruptures under the influence of a light bending force. Although this method is not new, it has been little used for this purpose in the past; nevertheless, it appears so attractive in its possibilities of speed, simplicity, and precision that the investigations presently to be described were undertaken to verify its merits. The redetermination of the solidus and eutectic temperatures of the lead-antimony system was employed as a medium 0f experimentation. New values obtained in this way are believed to be sufficiently precise to warrant a revision of the currently accepted lead-antimony phase diagram (Fig. I). Determinations of the solidus of the lead-rich lead-antimony alloy series have been published by R. S. Dean2 and by E. E. Schumacher and F. C. Nix.3 Their points are represented in Fig. I. In their work the solidus was not located at antimony concentrations greater than 2 per cent; the curve was presumed to meet the eutectic horizontal at an antimony concentration of about 2.5 per cent. In the present studies the solidus has been traced to 3.5 per cent, where the eutectic horizontal is intersected (Table I and Fig. I). Within the range investigated by Dean and by Schumacher and Nix the agreement with their values is good. H. Seltz and B. De Witt,4 on the basis of activity measurements, have calculated that the intersection of the solidus and the eutectic reaction horizontal should lie at 3.86 per cent of antimony. The following determinations of the eutectic temperature have been reported: Roland-Gosselin,5 228°C.; Ewen,6 228°C.; J. E. Stead,7 247°C.; Campbell,8 228°C.; W. Gontermann,9 245° to 252°C.; R. Loebe,10 245°C.; E. Heyn and 0. Bauer,11 245°C.; H. Endo,12 250°C.; R. S. Dean,2 249° to 258°C.; E. Abel, 0. Redlich, and J. Adler,13 245°C.; W. Broniewski and L. Sliwowski,14 250° to 252°C.; H. Seltz and B. De Witt,4 250°C. A temperature of 249°C- appears to have been generally accepted in recent years; it is the value most frequently obtained by the method of cooling curves. Values below 249°C. have usually been obtained by inferior cooling-curve techniques; those above 250°C., by the method of heating

Jan 1, 1942

By Richard E. Chism

I have thought it well to lay before the Institute some account of the Vallecillo Mines, now, I believe, the only paying ones in American hands in northeastern Mexico, including the States of Nuevo Leon, Coahuila and Tamaulipas. The authentic history of these mines dates from their ownership by an American Company in the year 1851, when they were bought by the Vallecillo Silver Mining Company of New York. They had been worked before by the Spaniards, but had been abandoned for many years, on account of the heavy expense of drainage and the constant incursions of the Indians. The company commenced work with several well-known New York capitalists among its stockholders, and had a large fund of both money and enthusiasm. The first point of attack was at a shaft on a mine known as the Jesus Maria, which had the most favorable traditions. Extensive buildings were put up, and two sets of pumps were successively tried. After the second pump, with a steam-cylinder 5 feet in diameter and 10 feet stroke and a plunger 20 inches in diameter, had failed to do more than hold the water, with infinite labor, at the 250 feet level, and after a thorough exploitation of the whole mine above that level had failed to yield more than some $30,000 worth of ore, it was resolved to abandon the effort. Operations were accordingly transferred to the old Dolores shaft, at a point about 21/2 miles to the

Jan 1, 1885

By J. M. Eldridge, P. Balk

Phosphosilicate glass films were formed, by reacting gaseous P2O5 with SiO2, over a large range of temperature (800° to 1200°C) and gas phase composition (nearly two orders of magnitude of effective P2Ospressure). The film compositions generally corresponded with the liquidus curve, delineating the maximum solubility of the tridymite Phase of SiO 2 in phosphosilicate liquid solution at the temperature of film formation. It is shown that the P2O5 concentration of the phosphosilicate liquid film tends to decrease by reaction with the underlying SiO 2 layer until the liquidus curve is reached. The validity of the thermodynamic argument used in this explanation is supported by the results of a determination of the composition of borosili-cute films, prepared by reacting gaseous B2O3 with SiO2 at different temperatures. The kinetics of phosphosilicate film formation were described by a model predicated on a steady-state diffusion of P2O5 through the film. UNDERSTANDING of the processes leading to formation of phosphosilicate and borosilicate glasses is of great importance for producing passivating layers on FET devices. Passivating films with optimum characteristics are preferably formed in a separate step, independent of the doping of the semiconductor.' The results of an investigation carried out to gain improved insight into the mechanism of glass formation are presented in this paper. It would be expected that application of the known Pz05-Si02 and B 2 O 3-SiO2 phase diagrams should be useful in extending understanding of the glass-forming processes. However, the question of the propriety of treating thermally grown SiO2 in these binary oxide systems by the methods of equilibrium thermodynamics must be considered when this application is attempted. Although Sah et a1.' and Allen et al. 3 investigated the kinetics of formation of phosphosilicate glass (PSG), they failed to adequately relate their diffusion models to the occurrence of experimentally observed phases in the PSG/SiO 2/Si system. Horuichi and yamaguchi4 investigated the diffusion of boron through an oxide layer and described their results in terms of a model similar to that of Sah and coworkers. More recently, Kooi 5 and Snow and Deal6 reported the compositions of PSG films formed by depositing P2 O 5 onto SiO2. These compositions apparently coincide with those at the liquidus curve delineating the maximum solubility of crystalline SiO2 in phosphosilicate liquid solutions. These authors did not discuss the thermodynamic implications of their results on the structure of thermally grown SiO2 films. The structure of thermally grown Sio2 films and that of vitreous silica are generally thought to be quite similar. Since the solubility of a substance depends on its structure, it is relevant that the solubility of vitreous silica in water7 is highly reproducible, like the solubility of thermally grown SiOz in phosphosilicate liquid. Furthermore, the vitreous silica-water system appears to be in true thermodynamic equilibrium (viz., the same solubility value can be approached from both supersaturated and under-saturated solutions). Sosman7 suggested that a type of two-dimensional lattice may form at the silica/solution interface, resulting in the observed solubility behavior that is characteristic of a crystalline solid. An alternative explanation may be that vitreous silica has a microcrystalline grain structure. Other investigators have suggested that vitreous silica has essentially the structure of B cristobalite,' or is composed of microcrystals of p tridymite or cristobalite, or a mixture of both. Presumably the grain size would be sufficiently large to minimize any appreciable contribution of the grain boundaries to the solubility of the crystalline matrix. The present investigation was carried out to clarify the significance of the boundaries in the Pa,-SiO, and B2O3-SiO2 Systems in determining PSG and BSG (borosilicate) film compositions. Furthermore, the kinetic data for PSG film formation were extended, using a wider range of formation parameters than were previously reported. One model describing the kinetics of film formation will be presented that is compatible with the thermodynamics of the Pa5-Si02 system. EXPERIMENTAL PROCEDURE Glass Film Preparation. SiO2 films (1000 to 8000A thick) were obtained by oxidation of silicon substrates in dry O2 at 1100°C. PSG and BSG films were prepared by exposing these layers to gaseous oxides obtained by reacting high-purity POC13 and BBr3, respectively, with O2. A double-columned saturator was used to ensure complete saturation of the N 2 carrier

Jan 1, 1969

By N. A. Gokcen, M. Ohtani

Thermodynamic intevaction pararnetevs of elements E2(2), for dilute binary solutions of a component "2" in liquid iron, i.e., E(22) = 9 In f2/?N2 where f2 is the activity coefficient and N2 the mole fraction, and E(3) 2 = In f2/ N3 dilute ternary solutions of "2" and "3," and the carbon saturation parameter sc(3) (In f c/ N3) N c/N Fe for N3 - 0, are critically examined and correlated. It has been found that the interaction parameters and the atomic numbers of alloying elements follow regular periodic putterns. PHYSICO-chemical behavior of alloying elements in molten iron have become the subject of numerous investigations during the past 25 years. Consequently, the mutual effects of elements in the iron-rich solutions Fe-C-X, Fe-N-X, Fe-H-X, Fe-O-X, and Fe-S-X where X represents an alloying element, have gradually become better understood. These effects for a given temperature and pressure may be expressed by the interaction parameter of Wagner1, 2 derived briefly in the following manner. The complete differential of the Gibbs free-energy equation at constant temperature and pressure is dF = Fl dn, + F2 dn, + F3 dn3+ . . . [ 1] where F is the free energy; F 1, the partial molar free energy of "I"; and n,, the number of moles of "i." Cross-differentiation of this expression* *Cross-differentials are obtained as follows: Since the order of differentiation of F with n2 and n3 is immaterial, the left sides of the second differentials are equal, hence the derivation of Eq. [2] is obtained. For a dilute solution of components 2 and 3 in solvent 1, with the substitution of RT In f i = Fi xs for Fi where fi is the activity coefficient, and Fixs is the excess partial molar free energy, Eq. [2] becomes O) [3] where N2 and N, are the mole fractions. The interaction parameters are defined by

Jan 1, 1961

By Theron Wasson

The oil and gas fields of Michigan that have been under development since 1925 are in an area that extends across the middle of the lower peninsula from northeast to southwest, a distance of about 200 miles, and with a width of about 80 miles. In 19 years 70 fields have been discovered. Most of these are relatively small when compared with other oil-producing areas. This is borne out by the fact that since the first wells were drilled these fields have produced a total of only 204,000,000 bbl. However, Michigan is still maintaining its production, for during the past five years the annual production has remained fairly constant at approximately 20,000,000 bbl. Production for 1943, as reported by the Bureau of Mines, was 20,682,000 barrels. Roughly, one third oi Michigan's production in 1943 came from the Reed City field, which was discovered in 1941. During the year, 237 oil wells were completed in Michigan in 1943. The decrease of 56 from the 1942 total is probably due to the continuance of Government regulations requiring a 40-acre spacing pattern over most of the state. Fig. I shows the principal oil and gas fields of Michigan, and the columnar section, Fig. 2, shows the principal producing horizons in relation to the section drilled. The data of Table I and Table 2 have been carefully checked with previous reports to eliminate errors. Six new producing areas were discovered during 1943 and five areas discovered in 1942 were developed during the year. Both the new discoveries and the 1942 discoveries that were developed appear to be small and relatively unimportant. Goodwell Field.—The best discovery of the year is the Goodwell field, T. 14 N., R. 11 W., Goodwell township, Newaygo County. This small structure was located by core testing done by The Pure Oil Co. in 1942 and early 1943. The first producing well, C. R. Harris No. I, was completed on July 5, 1943, ill the Traverse limestone at a total depth of 2742 ft., with ail estimated potential of 1100 bbl. per day. By the end of the year, 18 wells had been completed in this field and approximately 281,000 bbl. of oil produced. The field operated under proration of 262 bbl. per day per well from Oct. I to Dec. I; 150 bbl. per day per well after that date. Woodville Field.—The small Woodville pool, T. 15 N., R. 11 W., 3 miles north of the Goodwell field, was discovered by core testing by the Ohio Oil Co. The discovery well was completed on May 5, 1943, flowing 650 bbl. of fluid, including 18 per cent salt water the first 18 hr., from the Traverse limestone at a depth of 2810 to 2815 ft. Seven wells had been completed by the end of the year and 67,000 bbl. of oil had been produced. Development is now practically at a standstill because further drilling does not aDDear economically iustified.

Jan 1, 1944

By Theron Wasson

The oil and gas fields of Michigan that have been under development since 1925 are in an area that extends across the middle of the lower peninsula from northeast to southwest, a distance of about 200 miles, and with a width of about 80 miles. In 19 years 70 fields have been discovered. Most of these are relatively small when compared with other oil-producing areas. This is borne out by the fact that since the first wells were drilled these fields have produced a total of only 204,000,000 bbl. However, Michigan is still maintaining its production, for during the past five years the annual production has remained fairly constant at approximately 20,000,000 bbl. Production for 1943, as reported by the Bureau of Mines, was 20,682,000 barrels. Roughly, one third oi Michigan's production in 1943 came from the Reed City field, which was discovered in 1941. During the year, 237 oil wells were completed in Michigan in 1943. The decrease of 56 from the 1942 total is probably due to the continuance of Government regulations requiring a 40-acre spacing pattern over most of the state. Fig. I shows the principal oil and gas fields of Michigan, and the columnar section, Fig. 2, shows the principal producing horizons in relation to the section drilled. The data of Table I and Table 2 have been carefully checked with previous reports to eliminate errors. Six new producing areas were discovered during 1943 and five areas discovered in 1942 were developed during the year. Both the new discoveries and the 1942 discoveries that were developed appear to be small and relatively unimportant. Goodwell Field.—The best discovery of the year is the Goodwell field, T. 14 N., R. 11 W., Goodwell township, Newaygo County. This small structure was located by core testing done by The Pure Oil Co. in 1942 and early 1943. The first producing well, C. R. Harris No. I, was completed on July 5, 1943, ill the Traverse limestone at a total depth of 2742 ft., with ail estimated potential of 1100 bbl. per day. By the end of the year, 18 wells had been completed in this field and approximately 281,000 bbl. of oil produced. The field operated under proration of 262 bbl. per day per well from Oct. I to Dec. I; 150 bbl. per day per well after that date. Woodville Field.—The small Woodville pool, T. 15 N., R. 11 W., 3 miles north of the Goodwell field, was discovered by core testing by the Ohio Oil Co. The discovery well was completed on May 5, 1943, flowing 650 bbl. of fluid, including 18 per cent salt water the first 18 hr., from the Traverse limestone at a depth of 2810 to 2815 ft. Seven wells had been completed by the end of the year and 67,000 bbl. of oil had been produced. Development is now practically at a standstill because further drilling does not aDDear economically iustified.

Jan 1, 1944

By Clarence Zener

THE internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites,4,5 localized weak regions introduced by cold-working,6,7 grain boundaries and possibly twinning planes.8,9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation. was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, ½ in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff.10 EXPERIMENTAL METHOD The experimental method used has previously been described in Institute papers.5,6,9 The measure of internal friction adopted here, 1/Q, is (1/p) X the logarithmic decrement, a measure used by some writers, and is also (1/2p) X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the funda¬mental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. EXPERIMENTAL RESULTS The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. 1, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of l00 during the next 100° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e~H/RT [I]

Jan 1, 1942

By Morris Cohen, Robert C. Ruhl

The phases in Fe-C alloys over a wide composition range have been studied after splal quenching from the liquid state. Binary alloys containing 0 to 5.1 wt pel C as /cell as a large number of ternary Fe-C-Si alloys with 2.5 to 5.0 wt pct C and 0.3 to 5.1 wt pct Si were attlong those sludied. Olher Fe-C-X alloys, zcilh X being Co, Cr, ,Wn, Ni, and Ru , were also inrestigated after splat quenching. At high carbon contents, a new hcp phase (designaled 6 phase, but different from e carbide) is retained upon splat quenching. The .fraction of this phase varies up lo 97 pcl for a Fe-4.K-1.9% alloy. The composition of the E phase ranges from about 3.8 10 4.8 wt pet C, and the corresponding laltice parameters increase linearly ulith carbon content, while the c/a ratio remains essentially conslc~nl. The E phrtse appears to he a solulion of carbon in E iron, the latler being nornially found only at high pressures. It is deduced that the unit cell of the E phase corresponds to the formula Fe12C3, and llzal il is relaled to tlie ordered slruclures 0.f 6 iron carbide and c iron nilride. The E phase is compared and contrasted to the olher known carbides and nitrides of iron and nickel. An exlrapolaTion of the atomic volume 1,s carhon conlent of /he E pllase lzcts giz.en a neu7 estitnale jor /he alomic volume of E iron, 11.30 cu A, a1 atmospheric pressure and temperature. Other alomic volume relalionships lead to /he co~zpositioti Fe2.iC tor E iron carbide, /he unit cell fortr~ula being -Fe2rClo The E phase undergoes a lulo-slage decomposition upon healing, .forrning firsl rnarlensile plus E carhide, a/ler 1 hr at 140" lo 200°C, slid then ferr ite Plus cementile, after 1 lir a1 330" to 460°C. A1 carbo,l contents between 1.5 and 3.0 LC/ pcl, (he predo.wirzar/t plzase alley quenching is fcc austenite. The retained carbon content of this phase increases with itlcreasing silicon in certain concentration ranges, reaching a maximum of 2.37 wt pct C itz a Fe-2.6C-4.OSi alloy. This is the highest carbon conten1 reLaitled in austenite to date. These high-carbon aus-tenites can be partially tm?zsforttled lo tnartensile hy severe deformation in the temperature range of — 190 to -50°C. TECHNIQUES for splat quenching from the liquid state have been utilized in numerous recent investigations to produce metastable phases in a variety of alloy systems. Among the several ways of splat quenching, the shock-tube method appears to yield the highest cooling rates1-3, 7, 8 and was adopted here. Estimated cooling rates attained in the present experiments ranged from 10' to 10 80Cper sec.' As a part of a research program on interstitial al- loy phases, the Fe-C system was selected for splat-quenching studies. It was hoped that splat quenching would allow high metastable supersaturations of carbon to be retained in solution. Also of considerable interest were the conditions governing the occurrence of the various intermediate phases upon solidification. The alloys investigated included both binary Fe-C compositions as well as six ternary Fe-C-X alloy systems. The known phases in the Fe-C system are summarized in Table I.* Only the ferrite and graphite are ent investigation.14 and is described in detail herein Table II summarizes corresponding data on Fe-N phases, which are also of interest here because of their similarity to the Fe-C phases. EXPERIMENTAL PROCEDURES Alloys were prepared by melting the elements. 99.9 pct purity, in an inert gas nonconsumable electrode arc furnace. The buttons. weighing about 5 g. were remelted twice. were then fragmented. and their interior surfaces were examined for uniformity: if any doubt existed. they were remelted again. Chemical analyses were performed on all the alloys. the accuracy being about k0.05 wt pct. At high temperatures, carbon-containing alloys react with alumina crucibles as follows: If the atmosphere in the splat-quenching furnace does not contain sufficient carbon monoxide the alloy can be depleted of carbon and contaminated with aluminum. Calculations and experimental observations showed that 50 to 100 torr CO partial pressure effectively blocked the above reaction in all the alloys investigated. The splat-quenching equipment in Figs. 1 and 2 provides for evacuation and back-filling with CO-Ar mixtures. The furnace is capable of operation up to 1650°C. and the gettering action of the graphite heating element reduces the oxygen partial pressure in the furnace atmosphere to below 10-5 torr, thus preventing oxidation of the specimens.

Jan 1, 1970