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By G. P. Gladis, R. H. Atkinson

PALLADIUM has been used for jewelry for many years, particularly in conjunction with gold. This use increased in amount during the war, as palladium and gold were only moderately used for war purposes while demands for platinum and some of the other members of the platinum group were so great that their use in jewelry was prohibited. Palladium hardened with a small percentage of ruthenium has the necessary technical properties and appearance for good jewelry, and it is sufficiently rare to be desirable for luxury items-at least 100 times as rare as gold. Although both visual and spectrophotometric examination demonstrated that the color of palladium was almost the same as that of platinum, a few jewelers found the surface of palladium, even after some polishing, rather dark in areas that had been repeatedly heated during the soldering necessary to assemble certain types of handmade ornaments. This phenomenon is not to be confused with the thin, bluish oxide film that can be produced by heating in air over the range 400° to 800°C., as that film is easily reduced by dipping in warm 5 per cent formic acid or in warm methanol. It was suspected that the difficulty arose from heating in atmospheres that were alternately oxidizing and reducing, as Wise and Vines1 had found that this opened the grain boundaries of palladium and palladium-silver alloys in the same manner as in pure silver, as reported by Martin and Parker.2 This damage is caused by the reaction between oxygen in solid solution in the metal, acquired when heated under oxidizing conditions, and hydrogen diffusing in from subsequent heating under reducing conditions; the steam cannot diffuse out and therefore builds up sufficient pressure to disrupt the metal near the surface. Copper and various other metals can be damaged similarly, but platinum is nearly immune; therefore the problem was new to the platinum jeweler. Sulphur in the fuel gas also can cause trouble but did not appear to be dominant in the present instance. Metallographic examination of both pure palladium and ruthenium-palladium showed that the usual torch using oxygen and city gas as normally operated did in fact cause the surface and subsurface damage that had been observed, and also disclosed that a reducing flame caused more damage than an oxidizing flame and was very damaging even in the absence of any intentional swing in atmosphere from oxidizing to reducing (Fig. 7); besides the surface damage, there was serious loss of ductility. A full explanation of the mechanism of attack is not evident at the moment, but may be allied to the attack that occurs on heating catalytically active metals in nonequilibrium atmospheres.

Jan 1, 1946

By H. Majima, E. Peters

The oxidation rates of pyrite, pyrrhotite, chalcopy-rite, chalcocite, covellite, bortzite, galem, sphalerite, and stibnite have beet2 carefully compared at 120 oC, using aqueous phosphate solutions buffered at pH 2.7, 7.1, and 11.2 as zvell as in 1.0 M NaOH and in am~onia-containing solutions. Under conditions of these studies, variations in rates of more than a factor of two per unit of mineral surface area were not observed for different minerals in phosphate buffered solutions, except that pyrrhotite showed unusually rapid oxidation rates In acid solutions, and stibnite showed very rapid oxidation rates in basic solutions. In caustic solutions, oxidation vates varied considerably, the most rapid being for pyrite and the slowest for sphalerite. In the presence of ammonia, only copper minerals showed more vapid oxidation rates in neutral solutions. Oxidation rates were measured on the basis of oxygen-consunzption rates per unit surface area of exposed mineral, using equivalent surface areas, mineral mesh sizes, pulp densities, agitation, and oxygen pressure. OXIDIZING pressure leaching of sulfide minerals has been a commercial method of treating concentrates of nickel, cobalt, and copper for over a decade, and recently the treatment of lead and zinc concentrates,' and even the recovery of sulfur from pyrrhotite by such processes, have been shown to be technically feasible.' Furthermore, the leaching of uranium ores by solutions acidified through the oxidation of pyrite and other sulfides present in the ore is commercially practicable.3 5 The mechanisms by which sulfide minerals oxidize in aqueous environments are not yet understood. However, certain generalities can be made for systems containing no unusual reagents, in which oxygen is the oxidizing agent. In acid solutions the oxidation of many sulfide minerals leads to the formation of elemental sulfur.8'7 The attack of some sulfides, notably galena (PbS), sphalerite (ZnS), and pyrrhotite (FeS), at temperatures below about 110°C leads to an almost quantitative conversion of the sulfide mineral to elemental sulfur according to the equation: On the other hand pyrite (FeS2) and copper minerals do not yield elemental sulfur quantitatively. Not more than 50 pct of the sulfur in pyrite is converted to the elemental form in acid oxidation, and this percentage is lowered by higher temperatures and possibly higher oxygen pressures.8'9 Copper minerals sometimes yield elemental sulfurlo'" but, since sulfur can reduce cupric ions with the precipitation of CuS or Cu2S, it is not likely that elemental sulfur is obtained in good yield. In acid solutions sulfur that is not converted to the elemental form always appears as sulfate salts or sulfuric acid. Sulfide minerals that yield elemental sulfur nearly quantitatively on oxidation in acid solutions tend to generate H2S when the conditions are not oxidizing. However, although it has been suggested that H2S is an essential intermediate in the mechanism of oxidation," this is doubtful because it is oxidized very slowly by oxygen. In basic solutions elemental sulfur is never formed, as predicted by thermodynamical considerations, summarized in the form of a potential-pH diagram in Fig. 1. However in neutral and basic solutions, unstable forms of sulfur not shown in the diagram appear during oxidation, notably thiosulfate (SOT-) and polythi-onates (S,O;-, x = 2 to 6).l3,l4 On prolonged oxidation only hexavalent sulfur as sulfate (SOi-) or sulfamate (NHzSO;) is found to remain, the latter appearing only in the presence of ammonia. The oxidation kinetics for thiosulfate by oxygen are the subject of a separate paper,'5 and were studied on the presumption that thiosulfate may, in fact, be a primary oxidation product for sulfide minerals, at least in neutral and basic solutions. A survey of the literature indicated that comparative oxidation rates for different sulfide minerals were needed to establish the role of the mineral structure and its thermodynamic properties on the oxidation rates and mechanisms.

Jan 1, 1967

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By C. W. Vaupell

The Huitzuco mines lie in north central Guerrero, Mexico; production has been about 90,000 flasks of quicksilver since 1873. Near-surface ores fill extinct mud geysers and the deep deposits are chambered veins, stock-works in brecciated blocks, and replacements in limestone. The epigenetic minerals livingstonite, stibnite and sulphur occur in limestone, gypsum and dolomite through a developed vertical range of 260 meters. The deepest workings expose an increased amount of stibnite, which probably indicates that the lower limit of mercury mineralization is being approached. A resurgence of heat and water formed geysers over an extended area after the period of mercury mineralization. Mud geysers, which are situated, in the outcrops, contain the secondary mercury minerals, cinnabar and barccnite in the gravel and mud filling the vents. A 150-ton flotation plant is in operation concentrating stope fills that assay 3.0 kg. of mercury per ton. In one open stope, which is more than one hectare in area and 60 m. high, 150,000 tons are available. Introduction The Huitzuco mercury mines are of interest because of the unusual occurrence of ore in extinct geyser vents and the presence of several rare mercury minerals. Some of the deposits have typical characteristics of the telethermal zone and there is a gradation towards typical epithermal mineralization in depth. Halse,1 Villarel1o,2 Mactear3 and Merri114 have described the geology and the early operations in the district, and Bar-cena5 and Mallet6 have described the rare mercury minerals, livingstonite and barcenite, found at Huitzuco. Location The village of Huitzuco lies in the north central part of the State of (Guerrero, Mexico, 27 km. (16.7 miles) east of Iguala, which is the largest and most important town in the area. Iguala is served by the Mexican National Railways and also by the Mexico City-Acapulco highway. The highway is surfaced from Mexico City to Iguala, a distance of 200 km. (124 miles) by road, and there is a fairly good, level, dirt road from Iguala to Huitzuco. The elevation above sea level is about 1000 m. (3280 ft.). The climate is warm and very dry except during the rainy season, from June to

Jan 1, 1941

By N. A. DeCecco, H. M. Meyer

IN the early stages of a titanium brazing investigation, binary titanium systems partially or completely known and fundamental metallurgical data were surveyed to select the pure metal most likely to be satisfactory for producing a ductile high strength joint. The phase diagrams for the purpose of this survey were classified into two groups: 1—systems with large solubility in ß titanium, but negligible solubility in a titanium, and 2—systems with large solubility in a titanium. Those metals with melting points believed to be too high or too low for titanium brazing (Tim = 1730°C) were eliminated from consideration. The melting points of vanadium, tungsten, tantalum, hafnium, zirconium, and the platinum group are too high and those of zinc, lead, cadmium, and tin are too low. The remaining metals were grouped as follows: 1—large ß solubility: Cr,¹ Mn,² Fe;³ CO,4 Ni,5 Cu,6 Be,' Si." —large a solubility: Al.9

Jan 1, 1954

By N. F. Neumann, A. W. Schlechten

Metal chlorides were formed by reacting metal oxides and calcium chloride; the effect of additions to the reaction mixture was studied. It was found that by use of proper additions, metal chlorides could be prepared from mixtures that were not reactive under ordinary conditions. ManY recent metallurgical developments involve the use of chlorine or chlorides as primary reagents; good examples are found in the production of ductile zirconium and titanium by reduction of their chlorides with magnesium. Various methods of preparing metal chlorides are used and many others have been proposed. Some chlorides are formed by the direct combination of a metal or alloy with chlorine. Other processes react chlorine and metallic oxides; carbon or other reducing agents are usually employed to reduce the metal oxides and so promote chlorination. Metallic chlorides have also been produced by the exchange of chlorine between metal oxides and a chloride, such as sodium chloride. This type of reaction was the basis for the old process of chloride roasting in which metal ores were roasted in the presence of salt. Soluble chlorides thus formed

Jan 1, 1959

By H. E. Searle, Robert J. McKay, O. B. J. Fraser

The practical study of corrosion requires consideration of its economic aspects. It must be based on sound scientific principles, but it should be borne in mind that probably the most important object of a corrosion test is to determine what metal in corrosion-resisting construction will produce the greatest operating profit. Thus the corrosion test must be directly connected with money values or it is not a practical corrosion test. This, perhaps unusual, connection between corrosion and economics is partially due to the fact that corrosion deals only with the time factor or duration of equipment, and it is almost the only test which deals with this feature. In these statements a departure is made from the academic definition of the word corrosion and it is done deliberately. The use of the term corrosion is unusual. It is as though we spoke of a tensile test as a "breaking" test. We are not interested primarily in the break but in the strength of the metal. There is no English word which expresses our main interest in corrosion-testing, but let us have clearly in mind that we make corrosion tests to prevent corrosion. Our real interest is in this corrosion-prevention, not in the corrosion. Previous to 1922, it was common comment that "it is impossible to determine the course of corrosion by laboratory testing.'' This statement was true at that time in that the technique of laboratory testing for corrosion resistance was so vague that tests in the laboratory gave untrue results almost as often as true ones. This was so, even in the simple case of determining which one of two metals better resists a given solution. While this is no longer true the number of misleading "corrosion tests" still being ground out by laboratories is too large in the light of our present knowledge. There are two important features of corrosion testing whose neglect is a large contributing factor to misleading results: (1) The economic relations of the corrosion tests to other tests; (2) testing technique. Regarding economic relations J. F. Thompson l has said: "The use of any particular metal is rarely based upon the sole property of resistance to corrosion. In fact, I should like to venture the assertion

Jan 1, 1929

By Robert J. McKay, O. B. J. Fraser, H. E. Searle

The practical study of corrosion requires consideration of its economic aspects. It must be based on sound scientific principles, but it should be borne in mind that probably the most important object of a corrosion test is to determine what metal in corrosion-resisting construction will produce the greatest operating profit. Thus the corrosion test must be directly connected with money values or it is not a practical corrosion test. This, perhaps unusual, connection between corrosion and economics is partially due to the fact that corrosion deals only with the time factor or duration of equipment, and it is almost the only test which deals with this feature. In these statements a departure is made from the academic definition of the word corrosion and it is done deliberately. The use of the term corrosion is unusual. It is as though we spoke of a tensile test as a "breaking" test. We are not interested primarily in the break but in the strength of the metal. There is no English word which expresses our main interest in corrosion-testing, but let us have clearly in mind that we make corrosion tests to prevent corrosion. Our real interest is in this corrosion-prevention, not in the corrosion. Previous to 1922, it was common comment that "it is impossible to determine the course of corrosion by laboratory testing.'' This statement was true at that time in that the technique of laboratory testing for corrosion resistance was so vague that tests in the laboratory gave untrue results almost as often as true ones. This was so, even in the simple case of determining which one of two metals better resists a given solution. While this is no longer true the number of misleading "corrosion tests" still being ground out by laboratories is too large in the light of our present knowledge. There are two important features of corrosion testing whose neglect is a large contributing factor to misleading results: (1) The economic relations of the corrosion tests to other tests; (2) testing technique. Regarding economic relations J. F. Thompson l has said: "The use of any particular metal is rarely based upon the sole property of resistance to corrosion. In fact, I should like to venture the assertion

Jan 1, 1929

By Frederick J. McGarry, Fred Moavenzadeh

An experimental investigation of the thermal and mechanical responses of rock materials to laser radiation is described. Specifically, the following three topics have been studied in detail: 1. Temperature measurements on thin discs subjected to laser radiation. 2. Strain measurements on thin discs subjected to laser radiation. 3. Observation and evaluation of cracking and spalling phenomena in constrained and unconstrained thin discs respectively, subjected to laser radiation. In conjunction with the experimental work done, use was made of a heat flow analysis and a stress analysis program developed for this purpose. It was possible to theoretically predict the thermal and mechanical responses of a rock specimen to laser radiation and then compare them with experimental observations. Good correlations were obtained.

Jan 1, 1971

By Charles H. Fulton

(Cleveland Meeting, October, 1912.) I. INTRODUCTION. THERE are comparatively few accurate data on the melting-or the freezing-point temperature of metallurgical slays, or on related physical phenomena, such as fluidity near the melting-point, specific heat, latent heat, etc. With the exception of the work of H. 0. Hoffman,1 and some older work by R. Akerman, P. Gredt, and H. M. Howe, no information is available that is of direct interest to the metallurgist. Hofman's valuable work is the only one that refers to slags produced in the metallurgy of copper and lead. The classic work of J. H. L. Vogt,2 who views slays from the standpoint of physical mixtures (solutions in which the entities are minerals), has opened up a. new field in the study of slags, and has placed the investigation of such properties as melting-temperatures, etc., on a rational basis. The recent work of A. L. Day, E. T. Allen, and W. P. White, of the Carnegie Institution, at Washington, and of European investigators 3 on certain systems of silicate minerals confirms the value of the investigation of silicate series from this standpoint, and it is my aim to apply this method to metallurgical slaws, in order to gain exact data of value in metallurgy. The work recorded in the present paper is the result of an investigation of reverberatory-furnace slags made for a Western smelting company to determine exactly the influence of change in composition, within comparatively narrow limits, on the melting-point. For a general discussion concerning the mineralogical character of slaws and the principles on which this investigation is based, reference should be made to other work,4 for the subject is too large to be stated in this paper, except very briefly in the following outline 1 Trans., xxix., 682 (1899). 2 Die Silikatschmelzlösungen; I. Ueber die Mineralbildung in Silikatschmelzlösungen; II Ueber die Schmelzpunkt-Erniedrigung der Silikatschmelzlösungen (Christiania, 1903-04). 3 Doelter, Handbuch der Mlineralehevu:e (1911) 4 C. H. Fulton, Principles (of Metallurgy. Chapter viii., on Slags, p. 24.5 (1910).

Dec 1, 1912

By Joe O. Ledbetter

INTRODUCTION Health physics as a profession really got a significant start during the Manhattan Project of World War 11. The Health Physics Society has recently published its 25th anniversary issue of the journal (June 1980). There was concern over radiation exposures during and after uranium production, especially about radium and its daughter products [Jackson 19401 and, as evidenced by the frequency of articles in the literature, there still is. The reason for this concern was expressed by Harley as "Workers engaged in the mining and pro- cessing of radium-bearing materials are exposed to dusts of the parent, to radon, and to the radon daughter products. In- haled radioactive particulates may be retained in the lung or redistributed to other organs of the body. Relatively minute de- posits of radioactive substances, particularly alpha emitters, have been clearly shown to be the etiological factor in a variety of injuries to industrial and re- search workers. " [Harley 1953] Emphasis in measurements has been placed on radium in water and radon in air, since these are the principal mobilized phases; however, it should be kept in mind that radium-containing particles do become suspended in air as aerosols and radon absorbs in liquids. Much of the uranium mining and production is being carried out aboveground. The principal difference between underground and surface (pit or leach) mining of uranium is the reversal in the relative importance of roles for the types of radiation dose. For aboveground the major radiation exposure is external gamma ray, whereas for underground it is internal alpha; for aboveground, the whole body penetrating is of greater importance than the lung alpha dose. AS a result of the politics involved and the law- suits for any and all diseases as being occupationally- caused, today , more than ever before, the successful performance of the activities connected with uranium production--before-, during-, and after-the-fact-- must include the provision of first class radiation protection. Such protection can be achieved by good measurements, thorough risk evaluations, and adequate controls. Meeting the ALARA (As Low As Reasonably Achievable) philosophy necessarily entails the determination of what is reasonable exposure. The necessary and sufficient elements of radiation safety under the ALARA dictum require a hard look at the dose versus effects data. There are times when the health physicist needs to make decisions of judgement rather than compliance with a well-defined regulation value. In order to facilitate such decisions, the real world must be separated from opinions that are merely artifacts of statistical variation and from the unprovable "what ifs" that are slanted to question the morality of any non-Luddite. UNITS VOCABULARY FOR DOSIMETRY There have been many radiation quantifying and dosimetric units introduced in the past. Fortunately, most of them did not catch on enough to become required knowledge for reading the health physics literature. The unit definitions necessary for our purposes here are the following: -curie (Ci)--unit of radioactivity equal to 3.7 x 10 10 disintegrations per second Webster&apos;s 19711 or the quantity of radionuclide that undergoes 3.7 x 10 nuclear transformations per second. Environmental levels of radioactivity are usually measured in picocuries (10-l2 Ci) per cubic meter for air and in picocuries per liter (pCi/~) for water and sometimes for air. .roentgen (R)--exposure dose of x or gamma rays that gives 1 esu of charge (either sign) to 1 cc of dry air @ STP. The roentgen is equivalent to an energy absorption of 86.7 ergs/g of air [Gloyna and Ledbetter 19691. .rad--radiation absorbed dose of 100 ergs per gram of absorber. The SI unit for absorbed radiation dose is the Gray; 1 Gy = 100 rads. orem--radiation absorbed dose of 1 rad times the quality factor (QF) for that radiation. The QF is 1 for x rays, gamma rays, beta rays, and posi- trons. For heavy ionizing particulate radiation, QF is a function of the amount of energy trans- ferred per unit length of travel, i.e. , the linear energy transfer (LET); the values of QF:LET in keV/um are as follows: 1:<3.5; 1-2:3.5-7; 2-5:7-23; 5-10:23-53; and 10-20:53-175 [Morgan and Turner 19 671 . For radiobiology, relative biological effectiveness (RBE) is recommended for use instead of the quality factor above that is for radiation protection: the RBE is the ratio of the dose of 200 kVp x rays to the dose of radia- tion in question (both in rads) to cause the same

Jan 1, 1980

By H. J. Snyder

Both the room-temperature and 600°F (315°C) primary solid-solution phase boundaries for the silver comer of the Ag-Cd-In temary system have been determined using X-ray diffraction and metallo-graphic techniques. Solid solubility of indium in silver at room temperature and 600°F (315°C) is shown to be between 20.3 and 21.7 wt pct, and corrects the previously extrapolated value of 18 wt pct appearing in the literature. The solid solubility of cadmium in silver at room temperature, not previously established, is shown to be between 34.9 and 41.3 wt pct. The solid solubility of cadmium in silver at 600°F (315°C) is confirmed as 43.2 wt pct. The shape of the primary phase boundary line for the subject temary system appears straight at room temperature and curves con-vexly towards the solvent (silver) comer at 600°F (315°C). THIS investigation was undertaken to initiate development of the Ag-Cd-In ternary diagram by establishing the primary solid-solution phase boundary in the silver corner of the diagram. At the present time, a diagram for this ternary system is not available, while this system appears to offer potential for a variety of uses. One alloy in the system has already proven to be useful as a control rod material in nuclear reactors.1"3 To encourage additional exploration of the potential of the system an understanding of its ternary diagram would be beneficial. It is towards this end that the present study is directed. LITERATURE SURVEY In undertaking this study, a comprehensive literature survey was first conducted to find information that would be useful for guidance. Useful knowledge did result from investigating the respective solubilities of indium and cadmium in silver as indicated in the binary constitutional diagrams of the systems Ag-In and Ag-Cd and also reviewing possible shapes of ternary primary phase boundaries. Weibke and Eggers~ used metallographic techniques to establish the system In-Ag as illustrated in Fig. Is This diagram shows that silver in the solid state is capable of dissolving approximately 18 wt pct In. This solid solubility of indium in silver holds true from room temperature up to 1276°F (691°C), then decreases continuously up to 1&apos;761°F (960.5"C), the melting point of the silver. The solid-solubility limit of indium in silver established by Weibke and Eggers has been confirmed by Hume-Rothery and Reyno1ds. G Durrant&apos; used a method which consisted of microscopic examination of quenched specimens to establish the Cd-Ag system as displayed in Fig. 2.&apos; The primary phase boundary of Fig. 2 proved to be in good agreement (ie., within 1 wt pct) with other studies*&apos;1&apos; of the Ag-Cd system made using X-rays and metallog-

Jan 1, 1968

By D. J. Mack, R. E. Reiswig

Six examples of the peritectoid transformation were selected from the literature and studied by the method of isothermal transformation. The kinetics and mechanisms of five of the examples are presented as TTT diagrams and photomicrographs. The exist-enc- of a peritectoid in the sixth case is doubtful. ALTHOUGH the peritectoid transformation per se has been known for many years, no precise published data exist concerning the kinetics or mechanisms involved in transformations of this type, except for the brief treatment by Rhines, et al. 1,10 Bearing in mind the fact that investigations of recent years are uncovering more and more peritectoids and suspected peritectoids, a thorough study of the well-established peritectoids appeared to be in order. It was for this reason that a study of the kinetics and morphological mechanisms of six binary peritectoids was undertaken. The six peritectoids selected from the literature for study were those reported at 7.02 wt pct Al-Ag, 26.0 wt pct Sb-Cu, 30.5 wt pct Sb-Cu, 32.3 wt pct Sn-Cu, 8.35 wt pct Si-Cu, and 21.2 wt pct Al-Cu. These selections were based on availability and purity of components, ease of preparation and heat-treatment, and estimated reliability of the available equilibrium diagrams in the regions of interest. EXPERIMENTAL PROCEDURE The alloys used in this investigation were induction melted in electrode-grade graphite and chill-cast in cast-iron split molds. In all cases, the alloys were so brittle that they could easily be broken into samples weighing 1 or 2 g. Chemical analyses showed that the alloys used were close to the respective peritectoid compositions reported in the literature and that the impurity levels were low in all cases. Metallographic examination showed uniform distributions of phases in all samples, indicating uniformity of composition in the samples studied. Isothermal transformation studies were carried out in fused-salt media, using the familiar inter-rupted-quench method. Uniformity of temperature in the salt baths was maintained by continuous stirring with a stainless-steel agitator. On the basis of actual observations of the temperature fluctuations, the estimated temperature control was + 10C for the Ag-Al and Cu-Sb alloys and ±30C for the Cu-Sn, Cu-Si, and Cu-Al alloys. The accuracy of all temperature measurements was estimated to be ±1°C. It was found necessary to mount metallographic specimens of the Ag-Al alloy in cold-curing methyl methacrylate, since the temperatures encountered in mounting in bakelite or lucite caused an appreciable degree of transformation to the ß phase. For the other alloys, wood-flour-filled bakelite mounts were used to avoid extraneous X-ray diffraction lines during the later examination of the metallographic specimens on a Norelco Geiger-counter d if f r ac tomete r. In the X-ray diffraction procedure, agreement between the published diffraction patterns and those obtained in this study was good. This was particularly important for phase identification, since the literature contained little in the way of micrograph description in some cases. Etching of the silver-aluminum alloy for metallographic examination was done by swabbing with either of the following reagents: 1) 10 g CrO3, 1 g (NH4), SO2, 0.5 g NH4NO3, 100 ml H2O, or 2) 10 ml NH4OH, 1 ml 20 pct KOH, 4 ml 3 pct H2O2, 5 ml H2O. The other alloys were etched with the usual bichromate etchant: 2 g K2Cr2O7, 1.5 g NaC1, 8 ml conc. H2SO4, 100 ml H20 (swabbed vigorously). EXPERIMENTAL RESULTS A) The Ag-Al peritectoid at 7.02 wt pct Al— The phase equilibrium involved in this peritectoid is shown in Fig. I.2 The phase boundaries in the vicinity of the peritectoid were most comprehensively established by Hume-Rothery, et al,3 who placed the equilibrium temperature at 448 °C and the equilibrium compositions of the a ß&apos; and y phases at 6.11, 7.02, and 7.24 wt pct Al, respective The alloy used in this study analyzed4 6.95 wt pct A making it slightly hypoperitectoid according to the accepted equilibrium diagram. The rate of the transformation a+ y — ß&apos; varies rapidly with degree of undercooling below the equilibrium temperature, passing through a maximum in the vicinity of 350°C. Thus the TTT dia-

Jan 1, 1960

By Wayne E. Glenn, R. W. French, Lincoln F. Elkins

The Lance Creek Sundance reservoir provides a case history of ro years performance of a reservoir in which unit operation has permitted effective utilization of gravity drainage augmented by primary pressure control with injection of gas into top structural wells. Detailed performance of the reservoir is presented by means of maps of Well status, reservoir pressure, individual well recovery, etc., and by pool-performance charts. Analysis of reservoir performance indicates only minor water encroachment, so that gravity, injected gas, and expansion of gas are the main oil-expulsive agents. A simplified theory of regional drainage of oil from upstructure location to downstructure location due to gravity is presented and checked by means of comparison of "reservoir" permeability and "well" permeability from the pool performance. Good order of magnitude agreement was obtained. Individual well performance and overall reservoir performance indicate possibility that maintenance of pressure makes ineffective those parts of the reservoir in which permeability is too low to permit effective drainage of oil by action of gravity. Oil from these parts can be recovered only when pressure is reduced locally by selective withdrawal or when overall reservoir pressure is finally reduced.

Jan 1, 1949

Jan 1, 1968

Jan 1, 1967

By Stanley C. Herold

TWENTY-FIVE years ago no distinction was made between water wells and oil wells except in the nature of the fluid produced. Water wells usually showed no decline in their rate of production; when oil wells showed decline something in the manner of handling them was considered wrong. Both water and oil were believed to be subject to the same physical laws in their underground movement toward the wells. Today a sharp distinction is made between them. Whereas water exists alone in the porous formations at depth, oil is usually accompanied by gas. This mixture does not behave as a liquid alone. It is a frothy, seething mass of foam which approaches and enters the wells. Different physical laws come into play. Twenty-five years ago attention was directed entirely to the well itself; today the well is accepted as a mere hole in the ground, a hole to be equipped properly for efficient service, yet without any value whatever unless it is backed up by a sufficiently prolific reservoir. Then, we were concerned with wells alone, 3000 ft. in depth; now commercial wells and their reservoirs are 10.000 ft. deep. Petroleum engineering concepts have necessarily therefore undergone a change in this last quarter century. What are they today?

Jan 1, 1937

By A. B. Parsons

AT the outset, the authors of this paper desire to file a disclaimer and an, explanation. They have no inside information from occult sources; neither of them feigns clairvoyant powers in the slightest degree. It is true that they have indicated on be graphs an approximate trend for the consumption of seven important mineral commodities up to the year 1954. At best this is a risky business; the figures do not pretend to be any- thing more than reasoned conjectures that are predicated on an attempt to evaluate some of the more obvious of the many factors that are likely to have a bearing on the future.

Jan 1, 1937

By Paul A. Farrar, Sanford Adler

The Tz-Zr system was reinvestigated using both metallographic and X-ray diffraction techniques. It mas found that titanium and zirconium are soluble in all proportions in both the a and 0 phases. The minimum in the transformation was found at 50 at. pct and 535°C. THE Ti-Zr system has previously been the subject of several investigations.1-6 A study by Hayes et al.5 using magnesium-reduced titanium and zirconium melted in graphite crucibles indicated that the system was a continuous series of solid solutions in both a and 0 phases with a minimum at approximately 545°C and 65 pct* Zr. These conclusions were substantiated by the work of Duwez4 as well as by the limited data of Craighead et al.,3 Fast,2 and deBoer.1 However, a more recent investigation of the titanium-rich region by Ence and Margolin6 indicated that the solubility of zirconium in a, titanium at 500°C is approximately 22 pct with the a + 0 field extending to approximately 47 pct Zr. Therefore in order to resolve this discrepancy the following investigation was initiated. EXPERIMENTAL PROCEDURES The alloys used in this investigation were prepared as 20- to 30-g buttons by nonconsumable electrode melting in a helium atmosphere. The starting materials were Bureau of Mines titanium BHN 71 and Foot Mineral iodide crystal bar zirconium. The titanium was premelted before the alloys were prepared to avoid excessive weight losses in the final melting. The compositions of the alloys prepared were as follows: Ti-12.0, 22.2, 29.0, 39.6, 50.0, 58.0, 72.4, 83.5. and 90.8 pct Zr. Prior to heat treatment the alloys were cold-worked 10 to 20 pct, stopping at the first signs of cracking. Specimens for heat treatment were wrapped in molybdenum sheet and annealed in argon-filled quartz capsules for the following times and temperatures: 750°C-40 days, 675°C-61 days, 600°C—109 days, 575°C-112 days, 550°C-112 days, 525°C—127 days, and 450°C —153 days. Quenching was accomplished by breaking the capsules in an iced-brine solution. The standard techniques used for polishing the specimens involved belt grinding, grinding on emery paper, polishing electrolytically, and etching with Remington "A" etch7 or "R" etch 8 Debye-Scherrer X-ray powder photograms were obtained for a number of samples using a 114.6-mm camera and CuK, radiation. Exposure times were from 19 to 23 hr. The powder samples were obtained by filing to 270 mesh size. After filing the samples were wrapped in molybdenum foil capsuled in quartz and reannealed at the temperature of original heat treatments; following the heat treatment the samples were quenched into iced brine without breaking the capsules. RESULTS AND CONCLUSIONS On the basis of the microstructural examinations of the heat-treated samples and of the X-ray diffraction data, the Ti-Zr system shown in Fig. 1 was constructed. The data indicate that a, and 0 titanium form a complete series of solid solutions with a, and ß zirconium. The minimum was found to occur at 65 pct (50 at. pct) Zr and 535°C, in excellent agreement with the earlier investigations,1-5 see Fig. 2. Typical microstructures are shown in Figs. 3 to 7. Figs. 3, 4, and 5 show the 22.2, 39.6, and 50.0 pct Zr alloys after heat treatment at 675°C for 61 days with the 22.2 pct Zr showing equiaxed a, and the 39.6 pct Zr alloy a + transformed ß, while the 50 pct Zr alloy shows only transformed B. Figs. 6 and 7 show the 29.0 and 39.6 pct Zr alloys after heat treatment for 109 days at 600°C. The 29 pct Zr alloy has an equiaxed a structure while the 39.6 pct alloy has a partially recrystallized a+ß structure. X-ray diffraction data obtained from the 50 pct Zr alloys after heat treatment at 525° and 450°C as well as from the as-cold-rolled material showed only those lineos which couid be indexed a: a titanium, good agreement with the previously published values. 2,4,5,9 Chemical analysis* of the 50 pct Zr alloy

Jan 1, 1967