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By B. A. Cheadle, C. E. Ells

The ovienlalion of hexagonal a-zirconium crystals in cold-drawn Zircaloy-2 tubes and in both as-extruded and heat-treated Zr-2.5 wt pcl ND tubes has been rrleasured using the inverse Pole - figure technique. Uniaxial tensile tests hare shown the Zil-caloy-2 lubes to hare highly anisotropic delovmation behavior whereas heat-treated Zr-2.5 wt pet Nb tubes are nearly isotropic. The differences in deformation behavior are esbloilred from the observed textures of the tubes and the deformation systems known to oberate in Zircnloy,-3. Tlze vcsults lead to an explanation of the high effective strain observed fov the Zircaloy-2 tubes as colrzpared to heat-treated Zr-2.5 wt pet Nb tubes in restrained end burst tests at 280° to 300°C. THE Zr-2.5 wt pct Nb alloy. when heat-treated by quenching from temperatures slightly below the (a + p)/P phase boundary and subsequently aged at 500°C, has tensile strengths about 50 pct greater than those of 20 pct cold-worked Zircaloy-2.1 There is. therefore, considerable economic incentive to replace Zircaloy-2 with the heat-treated alloy in some in-reactor applications. notably for pressure tubes, where strength is a prime consideration. However, when tubes of Zr-2.5 wt pct Nb fabricated by extrusion and drawing prior to heat treatment were subjected to restrained end-burst tests at 300 °C. the circumferential expansion at failure1 was only 10 pct that of cold-drawn Zircaloy-2 tubes in similar tests,2 Table I. This result was not predicted from uniaxial tensile tests in which the ductilities of the two materials were quite similar.' The detailed requirement for ductility in pressure vessels has not yet been worked out. and comparison of the relative merits of cold-worked Zircaloy-2 and heat-treated Zr-2.5 wt pct Nb is further complicated by the irradiation-induced loss of ductility and hydrogen pickup each will undergo from reactor operation.1,2 Nevertheless. the lower circumferential expansion of the Zr-2.5 wt pct Nb tubes raised serious doubts on the advisability of their use as pressure vessels. For this reason, an investigation to determine the cause for different ductilities of the two types of tubes was initiated. From a study of uniaxial tensile properties and crystallographic orientation it has been found that the fracture ductilities observed in the burst tests can be related directly to the crystallographic ori-

Jan 1, 1965

By A. A. Smith

The application of indium to bearings was first advocated by C. F. Smsrtl in 1938, for the purpose of inhibiting corrosion of certain bearing alloys. He found that a thin layer of indium plated on the bearing surface and subsequently diffused at elevated temperatures markedly decreased the rate of corrosion in lubricating oils containing organic? acids. Most of his work was done on cadmium-base alloys, although he showed that the treatment was also effective for copper-lead and other; alloys. Since their introduction, indium-treated bearings have found considerable use, particularly in connection with airplane motors.2 Undoubtedly the effectiveness of the indium plate in resisting corrosion depends upon its relative concentration on the bearing surface after the diffusion treatment and after prolonged use at operating temperatures. Some diffusion experiments were made on a number of base metals that had been indium plated, to determine the depth of penetration after heating for reasonably long periods of time. As only the practical aspects were desired, no attempt was made to determine actual diffusion constants. Method Two different series of experiments were carried out to study the diffusion of indium into several base metals. Cast cylinders about one-inch diameter were machined to 0.750-in. diameter, so as to remove all surface imperfections, and final finishing was done with oo sandpaper. The original diameters were very carefully measured with micrometers and then a layer of indium was electrolytically deposited on the cylinders from a sulphate bath.3 In the first series of experiments, about 0.002 in. of indium' was deposited and diffusion, was carried out at 150°C. for a period of 500 hr. in a thermostatically controlled electric oven. After the diffusion period, successive layers were machined from the specimens and analyzed spectro-graphically and chemically—the spectro-graphic examination serving as a guide to determine which layers should be chemically analyzed. Apparently there was some surface oxidation of the indium plate due to the long heat-treatment, which may have had some effect on the diffusion. A1so, the cadmium alloy showed some incipient melting, which probably was caused by the formation of a low-melting eutectic. To eliminate these factors, another series of experiments was carried out by heating in an electrically heated, automatically controlled, oil bath at lower temperature. The preparation of the specimens was the same as before except that a layer of indium 0.0001 in. thick, an amount commonly used commercially on bearings, was deposited on each of the cylinders. Diffusion was carried out at 120°C. for a period of 200

Jan 1, 1944

By A. A. Smith

The application of indium to bearings was first advocated by C. F. Smsrtl in 1938, for the purpose of inhibiting corrosion of certain bearing alloys. He found that a thin layer of indium plated on the bearing surface and subsequently diffused at elevated temperatures markedly decreased the rate of corrosion in lubricating oils containing organic? acids. Most of his work was done on cadmium-base alloys, although he showed that the treatment was also effective for copper-lead and other; alloys. Since their introduction, indium-treated bearings have found considerable use, particularly in connection with airplane motors.2 Undoubtedly the effectiveness of the indium plate in resisting corrosion depends upon its relative concentration on the bearing surface after the diffusion treatment and after prolonged use at operating temperatures. Some diffusion experiments were made on a number of base metals that had been indium plated, to determine the depth of penetration after heating for reasonably long periods of time. As only the practical aspects were desired, no attempt was made to determine actual diffusion constants. Method Two different series of experiments were carried out to study the diffusion of indium into several base metals. Cast cylinders about one-inch diameter were machined to 0.750-in. diameter, so as to remove all surface imperfections, and final finishing was done with oo sandpaper. The original diameters were very carefully measured with micrometers and then a layer of indium was electrolytically deposited on the cylinders from a sulphate bath.3 In the first series of experiments, about 0.002 in. of indium' was deposited and diffusion, was carried out at 150°C. for a period of 500 hr. in a thermostatically controlled electric oven. After the diffusion period, successive layers were machined from the specimens and analyzed spectro-graphically and chemically—the spectro-graphic examination serving as a guide to determine which layers should be chemically analyzed. Apparently there was some surface oxidation of the indium plate due to the long heat-treatment, which may have had some effect on the diffusion. A1so, the cadmium alloy showed some incipient melting, which probably was caused by the formation of a low-melting eutectic. To eliminate these factors, another series of experiments was carried out by heating in an electrically heated, automatically controlled, oil bath at lower temperature. The preparation of the specimens was the same as before except that a layer of indium 0.0001 in. thick, an amount commonly used commercially on bearings, was deposited on each of the cylinders. Diffusion was carried out at 120°C. for a period of 200

Jan 1, 1944

By W. R. Johnson, M. Hansen, John M. Parks

AS part of a research project sponsored by the Signal Corps Engineering Laboratories, which had the objective of obtaining a magnet wire of good conductivity and low temperature coefficient of resistance, a comprehensive literature survey, supplemented by experimental work, revealed that a linear relationship exists for solid-solution alloys between the electrical conductivity, K, and the temperature coefficient, a, as expressed by the equation: k = a/ß where ß is constant for the solvent metal and a - per°C. tR0 It has long been known that the electrical conductivity at a given temperature and the temperature coefficient of resistance of binary alloys are related to their constitution by the LeChatelier-Guertler rules, as illustrated by Figs. 1 and 2: Rule 1—In alloy systems consisting of a heterogeneous mixture of two phases, the electrical conductivity and temperature coefficient vary as a straight line, if the composition of the alloys is given in volume percentage, Fig. 1. Rule 2—In solid solutions, the electrical conductivity and temperature coefficient are always lower than those of the solvent metal, and usually a considerable decrease occurs with the first small percentage additions of the solute metal, Fig. 2b. If the two components form a continuous series of solid solutions, the electrical conductivity and temperature coefficient curves take the form of a U-curve, Fig. 2a. That some kind of proportionality exists between electrical conductivity and temperature coefficient of resistance is implied by the LeChatelier-Guertler rules and by study of data such as those given by Smith and Palmer,' Fig. 3. Dellinger2 in 1910 first recognized this relationship in a number of commercial copper wires, ranging in conductivity from 94 to 100.7 pct I.A.C.S. He gave the ratio of temperature coefficient to the percentage of conductivity as a constant, C = 0.003939. A year later, Lindeck observed that the linear relationship was valid for a wider range of conductivity in "various sorts of copper," and concluded that the product of resistivity and temperature coefficient was 6.78x10-5 1.5 pct. Since then, this relationship seems to have been entirely ignored. Conductivity-Temperature Coefficient Relationship If the electrical conductivity of copper solid-solution alloys with phosphorus, silicon, arsenic, antimony, aluminum, nickel, manganese, and iron is plotted against the temperature coefficient of these alloys, the diagrams in Figs. 4 and 5 are obtained. Similar data were found with copper-rich solid solutions containing magnesium, cobalt, and titanium,'" as shown in Fig. 6. In all cases, a linear relationship exists. The point representing the highest

Jan 1, 1952

By H. Rosenthal, A. L. Jamieson

THE action of mercury on stressed brass to produce cracks was known before Moore, Beckinsale and Mallinson1 showed that actual season cracking did not occur spontaneously but could be induced by ammonia. These investigators studied other substances, including diphenylamine, without finding that anything other than ammonia could cause season cracking. Grimston2 reported season cracking in cartridge cases stored in wooden boxes wetted with dilute sulphuric acid pickling solution. Season cracking associated with sulphur dioxide, water vapor and air has been reported by Johnston,3 although he reported that trimethylamine and pyridine did not cause cracking. Jevons4 has ascribed season cracking of brass in certain instances to trimethylamine, "aldehyde amine," "ketone amine" and pyridine, but no experimental work was done evidently to prove this definitely. Pyridine was investigated by Morris,' who found it to have considerable cracking power. In the present investigation, the object was a qualitative evaluation of a number of representative amines with respect to their ability to cause season cracking. Thus it was desired only that an appreciable vapor pressure of each amine be obtained in order to make the test as severe as possible, without attempting to test equivalent concentrations for comparative purposes. METHODS Specimens Two types of specimen were used: I. Unannealed 70-30 brass cups formed from 0.040-in. thick sheet. Height of cup was 1 3/8 in. and diameter was 1 7/8 inches. 2. First draw pieces of caliber .50 cartridge cases in the unannealed condition (70-30 brass). The cups were representative of a thin wall and thin base specimen, whereas the draw pieces have a thick base (1/4 in.) and a thick wall (approximately 3/32 in.). Both types of specimens contained high residual stress and cracked in less than one minute in a solution of I per cent mercurous nitrate and I per cent nitric acid provided that this was preceded by a 30-sec. pickle in 40 per cent nitric acid. Specimens were prepared as follows: (I) degreased in trichlorethylene, (2) rinsed in H20, (3) pickled 5 min. in 10 per cent by volume H2SO4 (1.84 sp. gr.), (4) rinsed in H2O, and (5) dried. Amines Tested In selecting the amines, representatives of the three series of amines and one series of substituted amines were chosen. The aliphatic series was represented by the methyl and ethyl primary, secondary and tertiary amines. These are the simplest aliphatic amines. For the aromatic series, the phenyl primary, secondary and tertiary amines were selected as being the simplest. The heterocyclic series was represented by pyridine, which is a simple heterocyclic base (tertiary amine).

Jan 1, 1944

By Claude P. Heiner

mountain region to M tht Coast points for domestic consumption and for export are shown in Table 11. There is considerable disparity in rates from both Rock Springs, Wyo., and Castle Gate, Utah, to the four coast cities where the slack coal is to be used for purposes other than export. The rate on coal to be exported is the same from either starting point to any of the four coast cities even though there is a difference of as much as 341 miles in the shipping distance. It is interesting to note that the freight rate between Sunnyside, Utah, and Fontana, Calif., on coking coal is $5.05 per ton and that coal up to 8 in. can be moved on this rate if it is suitable for coking. This rate was published late in 1942 on a contemplated annual movement of more than 500,000 tons. There have been decreases in freight rates since 1923 on movements of slack coal from Utah into Seattle and Portland due to pressure on the railroads and to greater. quantity of coal shipped. It is the author,', opinion that a movement of slack coal in excess of 3 million tons of coal per year from Utah to any point in central California would justify a freight rate equal to that puhlished for Fontana, Calif.. or $5.05 per ton. The movement of 3 1/2 million tons of coal per year on the basis of 240 mine working days per year would require that 14,600 tons be handled each mine working day. If it is assumed that shipments could be arranged for a 6-day week, the average railway movement would he 11,200 tons, or approximately 3 trains containing fifty-five 70-ton coal cars per day. Such movements of coal would require railroad equipment represented by the investment amounts stated in Table 12 and entail the services of 250 men. Table 12 ... Railroad Equipment and Investment Required To Move 11,200 Tons of Coal a Day from Utah to California Railroad Equipment Cost 2800. 70-ton coal cara at $6.000 each $16,800.000 32 locomotives at $310.000 each. 9.920.000 Miscellaneous eauiument:.......... .5;000:000 Total........................ $31,720,000 It therefore appears that, under presently known mining methods, the lowest price at which coal could be sold f.0.b. the mine in amounts of 3 1/2 million tons per year for generation of power in central California would be $4.60. It also appears that the lowest freight rate that could be expecled between intermountain points and the central California area would be $5.05 per ton, making a total cost of coal delivered at a plant site of $9.65 per ton. Conelusions The following are the author's conclusions: 1. Coal mines in Utah and in the Kemmerer and Rock Springs districts of Wyoming could increase annual production by 6 1/2 million tons per year. 2. Under present conditions coal could probably be delivered to any steam electric plant in central California at a price not to exceed $9.65 per ton. 3. The use of coal at such a price, while higher than the equivalent present price of fuel oil, is entirely feasible. 4. There are adequate railroad facilities for movements of large quantities of coal from the intermountain region to the Rest Coast. 5. In a national emergency it probably would be extremely difficult, if not impossible, to obtain sufficient oil to meet requirements of the greatly expanded West Coast steam electric generatsing capacity. 6. The intermountain region contains ample coal reserves to supply all conceivable demands for West Coast power generation for a number of generations. 7. Increasing demands of labor threaten to lessen, if not eliminate, savings in cost of coal production through the use of new mining machinery. 8. Continuation of experiments in socialism by the Federal Government through construction of hydroelectric generating plants, particularly those unrelated to land-use reclamation, defies justification. Rates under this concept of a governmental function are subsidized through greater taxation of its people. Private capital is available to construct steam plants, or hydro plants where feasible, and should be permitted to continue in order to preserve the principles of our free enterprise system. DISCUSSION (L. C. McCabe and Robert P. Koenig, presiding) C. C;. BALl*—I was asked to lead off the discussion, but it is not with the thought that I might be able to add anything to the paper. The thoroughness with which it was prepared rather forestalls the asking of many questions. Your treatment, Mr. Heiner, is a very valuable contribution. I do want to suggest—that although you have limited your study to this specific question, with certain geographic limitations, many of the things in your paper apply just as well to the eastern coals. I want to agree 100 pct with your final conclusion concerning government-subsidized construction. Id. C. McCabe*—It is certainly worthwhile to take stock occasionally to see where we are going in problems of this nature. I agree with Mr. Heiner that ultimately the only reliable source of fuel that the West Coast has is coal hut the time factor is the difficult element to evaluate. Just before I came here I discussed this subject with N. B. Hinson, Vice President and Executixe Engineer of the Southern California Edison Company, and Chairman of the West Coast Inter-Power Exchange Committee. He has given much thought to utilities' fuel supply and it was very helpful to me in preparing a discussion of the paper to talk with him beforehand. Stock taking and forecasting of future development are essential to the continuing success of any enterprise. Mr. Heiner has called attention to the unprecedented growth of central and southern California and to the increased demands for fuel and power which have accompanied it. He discusses the increased fuel oil and natural gas requirements and the probable limits on the future use of these fuels and of hydroelectric power. In contrast to the calculable limits of these sources of electric energy, the author points to the availability of enormous reserves of coal in the Rocky Mountain States adjacent to the Pacific Coast which can be utilized for power generation. That there will be increased use of coal for power generation in the area under discussion is generally accepted hut it is in the timetable of such development that there is not complete agreement. In a recent report, Mr. Hinson reviewed the future power outlook for the Pacific southwest area. He pointed out that the use of steam plants in connection with water power plants in this region has made the maximum use of hydroelectric energy possible, and that the correct balance between hydro and steam generating plants produces the most economical overall system. Steam plants in the area which had been installed to protect against deficiency in hydro energy in dry years were used to carry war loads. Fortunately, no dry

Jan 1, 1950

By J. B. Cohen

In an investigation of the microstructure of shock-loaded metal specimens1 C. S. Smith found that there was little distortion of grain boundaries or change in external dimensions, although the hardness corresponded to that produced by severe rolling. Furthermore, the hardness of individual grains was independent of the deformation structures present; grains with no markings were as hard as those heavily populated with markings. These markings which resemble twins do not appear in copper until high shock-loads of the order of 200 kb are applied. It appears that due to the high velocity of a shock wave and its sharp front, heavy deformation takes place on a submicroscopic scale. In this work an attempt was made to examine this deformation, particularly at a load below which macroecopic markings appear. The broadening of 200 and 400 diffraction peaks was examined from the face of a poly crystalline sample normal to the direction of the shock wave. These peaks were chosen because the elastic constants in copper are such that residual strains would be greatest in the <100> directions; hence, the strain-broadening contribution to these peaks would be large in comparison to other sets. Also the broadening due to stacking faults and microtwins would be greatest with this set.2 A complete Fourier analysis of these peaks was made, as described by warren,&apos; using the Stokes correction with peaks from an annealed sample.3 With the aid of the U. S. Army Ordnance Corps EDVAC computer and a curve matching program, sixty sine and sixty cosine coefficients were obtained for each peak. The last of these was about 1.5 pct or less of the largest coefficient, indicating good representation. Transverse sections from a 1.5 in. rod of as-drawn electrolytic tough-pitch copper were reduced in cross-sectional area about 50 pct by cross rolling. Disks 1.5 in. in diam were recrystallized at 275 °C for 30 min and then at 300°C for the same time. The faces were polished and deeply etched in nitric acid to remove 25 mils. The grain size was 0.02 mm. Laue back-reflection patterns indicated the sample was well recrystallized. The two diffraction peaks from this sample were recorded on a Norelco diffractometer using filtered copper radiation. Peak intensities were kept less than 600 cps to assure linearity of the counter and circuitry. This sample was then placed between two rods of the same material and diameter. The top rod was 2.25 in. long and the bottom rod 1 in. long. (In

Jan 1, 1961

By A. A. Smith

THE application of indium to bearings was first advocated by C. F. Smart1 in 1938, for the purpose of inhibiting corrosion of certain bearing alloys. He found that a thin layer of indium plated on the bearing surface and subsequently diffused at elevated temperatures markedly decreased the rate of corrosion in lubricating oils containing organic acids. Most of his work was done on cadmium-base alloys, although he showed that the treatment was also effective for copper-lead and other alloys. Since their introduction, indium-treated bearings have found considerable use, particularly in connection with airplane motors.2 Undoubtedly the effectiveness of the indium plate in resisting corrosion depends upon its relative concentration on the bearing surface after the diffusion treatment and after prolonged use at operating temperatures. Some diffusion experiments were made on a number of base metals that had been indium plated, to determine the depth of penetration after heating for reasonably long periods of time. As only the practical aspects were desired, no attempt was made to determine actual diffusion constants. METHOD Two different series of experiments were carried out to study the diffusion of indium into several base metals. Cast cylinders about one-inch diameter were machined to 0.750-in. diameter, so as to remove all surface imperfections, and final finishing was done with oo sandpaper. The original diameters were very carefully measured with micrometers and then a layer of indium was electrolytically deposited on the cylinders from a sulphate bath.3 In the first series of experiments, about 0.002 in. of indium was deposited and diffusion was carried out at 150°C. for a period of 500 hr. in a thermostatically con- trolled electric oven. After the diffusion period, successive layers were machined from the specimens and analyzed spectro- graphically and chemically-the spectro- graphic examination serving as a guide to determine which layers should be chemically analyzed. Apparently there was some surface oxidation of the indium plate due to the long heat-treatment, which may have had some effect on the diffusion. Also, the cadmium alloy showed some incipient melting, which probably was caused by the formation of a low-melting eutectic. To eliminate these factors, another series of experiments was carried out by heating in an electrically heated, automatically controlled, oil bath at lower temperature. The preparation of the specimens was the same as before except that a layer of indium 0.0001 in. thick, an amount commonly used commercially on bearings, was deposited on each of the cylinders. Diffusion was carried out at l20°C. for a period of 200 hours.

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

ABERDEEN, ESTHER, U. S. Geological Survey, Washington, D. C. ALLEN, VICTOR T., Director Geology Department, Institute of Technology, St. Louis University, St. Louis, Missouri. BATES, THOMAS F., Associate Professor of Mineralogy, Department of Earth Sciences, School of Mineral Industries, The Pennsylvania State College, State College, Pennsylvania. BOLGER, ROBERT C., Geologist, Pennsylvania Topographic and Geologic Survey, Harrisburg, Pennsylvania. BRIDGE, JOSIAH, U. S. Geological Survey, Washington, D. C. BURST, JOHN F., Geologist, Exploration and Production Research Division, Shell Oil Company, Houston, Texas. CAMPBELL, IAN, Executive Officer, Division of Geological Sciences, California Institute of Technology, Pasadena, California. FLINT, DELOS E., U. S. Geological Survey, Washington, D. C. FREDERICKSON, A. F., Associate Professor of Geology (Geochemistry), Washington University, St. Louis, Missouri. GLASS, HERBERT, Illinois State Geological Survey, Urbana, Illinois. GORDON, MACKENZIE JR., Geologist, U. S. Geological Survey, Washington, D. C. GRIM, RALPH E., Research Professor, Department of Geology, University of Illinois, Urbana, Illinois. HARDER, E. C., Aluminium Secretariat Limited, Montreal, Que., Canada.

Jan 1, 1952

By P. G. Shewmon, H. E. Collins

We have studied the effect of adsorbed sulfur on the surface self-diffusion of copper using eight diflerent surface orientations and the grain boundary grooving method. The eight orientations studied were the four lying near the low-index surfaces—(loo), (Ill), and two directions in the (110)-plus four higher-index surfaces. Surface-diffusion measurements were made over a range of HZS concentrations (in Hz) from 3 to 1500 ppm between 830°and 1050°C. The results can be divided into two groups—Group 1 contains the two (110) surfaces while Group 2 contains the remaining six surfaces. In Group 1, increasing the temperature increases the effect of Hz S on DS for the Hz S range 5700 ppvn. Qs and Do increase with increasing H2S concentration in this Hz S range. Beyond this range, increasing the temperature decreases this effect on D,; also Q, and Do decrease. In Group 2, increasing the telnperature decreases the effect of H2 S on D, for the H2S range studied, and Qs and Do decrease with increasing Hz S concentration. In any study of surface phenomena, there invariably arises the question of the possible presence of and effect of adsorbed impurities. Such questions are well-founded since the presence of adsorbed atoms can sometimes produce marked changes in the kinetics of surface-energy-driven processes. In the last few years, values of the surface self-diffusion coefficient, D,, have been determined on a variety of metals by studying the decay of scratches or the growth of grain boundary grooves.L~3-L0~L3 Yet there has been relatively little work done in which the concentration of an adsorbed impurity was systematically varied and the effects observed. Work of this sort would provide some basis in fact for the assertions often made about the ro1.e of adsorbed impurities in the differences between the results of different workers in different atmospheres and on different metals. It also is relevant to those cases in which surface monolayers produce profound effects in commercially important processes. The most marked example of such effects is the ability of nickel or palladium to increase the sintering rate of tungsten by many orders of magnitude.&apos; The aim of this work was to study the effect of sulfur partial pressures on the surface self-diffusion of copper. It was felt that this in conjunction with a study of the degree of adsorption and type of active sites involvedL8 would provide a wide range of data for one system and hopefully lead to some insight into the mechanism by which sulfur adsorption influences copper diffusion. The main reasons for choosing the Cu-S system were, first, faceting was reported not to accompany the adsorption of sulfur. This is required if our experimental technique is to work. Second, Oudar has determined a high temperature adsorption isotherm for this system, an event which puts the Cu-S system almost in a class by itself.I4 EXPERIMENTAL PROCEDURE Initially, we considered studying the effect of an adsorbed impurity on surface self-diffusion of copper using isolated (or single) scratch smoothing as the technique and oxygen as the impurity. Copper was chosen as the material because the effects of orientation and anisotropy of the surface self-diffusion coefficient, D,, of copper in a dry hydrogen atmosphere had been studied extensively by Gjostein&apos; and by Shewmon and ~hoi.~,~ The isolated scratch technique was chosen because both the effects of surface orientation and anisotropy of D, in a given surface could be easily studied with this method.~ Oxygen was tried as the impurity because Robertson and Shewmon""~ had studied its adsorption on copper at 1000°C over the range of oxygen partial pressures of 10"22 to 10-l3 atm. After several preliminary runs, it became evident that neither the scratch technique nor the impurity oxygen would be satisfactory for this work. Scratching deforms an annealed surface so that the region near the scratches recrystallizes, thereby disrupting the scratch profiles. One can avoid this by deforming the specimen sufficiently before scratching to give complete recrystallization on subsequent heating.4 However, as a result of Gjostein&apos;s success in scratching and annealing undeformed gold single crystals without local recrystallization,13 we attempted something similar with copper single crystals using a 0.7-mil diamond phonograph needle mounted in a Tukon hardness tester. All specimens recrystallized upon being annealed. Also, some copper specimens were sent to Gjostein to be scratched using his technique. The results were the same. As a result, the scratch technique was dropped in favor of the grooving of symmetric grain boundaries. Preliminary work using oxygen showed that faceting began to occur before oxygen adsorption had any measurable effect on D, at 938°C (at Pbo/P, = 0.12). Since heavy faceting would interfere with the measurement, we decided to use a sulfur-containing atmosphere (H2S/H2). Work by Oudar and Benard&apos; and Robertson" showed that sulfur absorbed on copper and that faceting was not observed.

Jan 1, 1967

By A. U. Seybolt, R. A. Oriani

The pressure and composition of the solid solution of nitrogen in chromium has been investigated as a function of temperature. The partial molal heat of solution, the activity of nitrogen in solid solution, and the partial molal free energy have been computed. The enthalpy of three reactions is summarized: N + 2Cr(3) = Cr2N(4), H° = —28,500 cal per mol 1/2N2(p) + 2Cr(8) = Cr2N(3)1 ?HO = —23,500 cal per mol 1/2N2(p) = N, ?H° = 5,000 cal per mol. WORKERS who have investigated the problem of the preparation of ductile chromium have been concerned with the effects of minor amounts of impurities upon this refractory metal. In particular, gaseous impurities such as oxygen and nitrogen have been suspected of causing trouble because of many known cases where brittleness in transition elements has been definitely traced to these elements. In order to evaluate the possible effects of the nitrogen impurity in chromium, it appeared desirable to learn something of the dependence of the nitrogen solubility upon temperature and pressure. Previous Work Maier3 in 1942 in his treatise on sponge chromium reviewed the thermodynamics of the chromium nitrides Cr2N and CrN, both of which are well-estab- lished compounds, but which apparently have not been studied in much detail. Maier presented some free energy-temperature expressions for the reactions 2 Cr,N = 4 Cr + N2 [1] and 4 CrN = 2Cr2N + N2 PI based mainly on the work of Satoh2 and Sano." Pearson and Ende3 in 1953 briefly reviewed the thermodynamics of Cr-N using the same data available to Maier, and also derived a free energy-temperature expression for reaction 1. Of the two nitrides mentioned previously, the present investigation was only concerned with Cr,N, since this nitride is in equilibrium with the metal phase, at least over most of the temperature range, Blix4 in 1929 established the structure of Cr2N (close-packed-hexagonal) by X-ray diffraction methods, and indicated that its homogeneity limits extend from 11.2 pet to 15.1 wt pet N. At a temperature of 1200°C, 38 mm Hg from the Maier expression and 43 mm Hg from the Pearson

Jan 1, 1957

E. G. Spilsbury, Trenton, N. J.: Mr. Case&apos;s paper possesses much interest for me, because my attention was called many years ago (early in the seventies) to the deposit he describes, and his explorations seem to have confirmed the predictions I then made as to the form of the deposit, namely, that the ore would be found to occur, not, as was then imagined, in loose boulders, distribnted

Jan 1, 1894

PRESIDENT AND DIRECTOR JOHN R. SUMAN HOUSTON, TEXAS PAST PRESIDENTS AND DIRECTORS DONALD B. GILLIES CLEVELAND, OHIO H.- G. MOULTON NEW YORK, N.Y. TREASURER AND DIRECTOR KARL -EILERS SEA CLIFF, N. Y. VICE-PRESIDENTS AND DIRECTORS W. B. HENRY HOUSTON, TEXAS HENRY KRUMB NEW YORK, N. Y. ERIE V. DAVELER , NEW YORK N Y W. M PEIRCE PALMERTON, PA. PAUL D. MERICA NEW YORK, N. Y. LEROY SALSICH DULUTH, MINN.

Jan 1, 1941

By O. A. Knight

THE suppression of the austenite-martensite transformation that can be brought about by the addition of certain alloying elements, such as manganese or nickel, to plain carbon steel has been known for a long time, especially since Guillet&apos;s investigation at the beginning of this century. The extent to which the critical range is lowered depends upon the percentage and nature of the special element added. First the Ar1 point is lowered gradually, then at a certain percentage a sudden lowering to about 300° C. occurs. The addition of still larger percentages of the alloy may result in lowering the Ar1 point to room temperature or below, in which case the steel remains austenitic at room temperature, especially after rapid cooling. The effect of alloying elements of this general type on the lowering of the transformation temperature is well illustrated by Sauveur(1)§ in his Fig. 281a, reproduced here as Fig. 1. This type of curve is characteristic of both manganese and nickel though it requires about 2 1/2 times as much nickel as of manganese to produce the same result. The influence of nickel in retarding the transformation of austenite into the lower transition constituents is due to its lowering of the critical range of the steel, which is also well illustrated by Sauveur(1) (after Osmond) in his Fig. 284, reproduced here as Fig. 2. Scott(15) presents a diagram illustrating the effect of manganese on the Ac3 and Ar3 points which is strikingly similar to the diagram above referred to in Fig. 2 concerning the effect of nickel.

Jan 1, 1934

By Eugene S. Meieran

The effects of methods of crystal growing, wafer sawing, polishing, routine handling, diffusion, and epitaxial growth on the defects in GaAs are reviewed and studied using reflection and transmission X-ray topographic techniques. In general, it was found that boat-grown crystals exhibited fewer defects than Czochralski crystals, although all crystals showed large numbers of precipitates visible when examined in the electron microscope. Mechanical surface treatments such as sawing and mechanical polishing introduce damage to a depth of about 5 µ, most of which can be removed by suitable chemical or chem-mechanical polishing. In addition, defects can be introduced through routine handling of wafers, for example with metallic tweezers. These defects can be quite severe, and have been observed 20 µ below the wafer surface. Defects can also be introduced through diffusion and epitaxial growth. These defects, which include precipitates, growth pyramids, stacking faults, dislocations, and so forth, can be detrimental to device fabrication. It is shown that wafers or films which appear defect-free optically can contain defects visible in the X-ray topographs. WHILE the use of GaAs in the semiconductor industry has increased very rapidly in the last few years, due mainly to the recent development of many important GaAs devices,1,2 the major limit to the production of commercial quantities of many GaAs devices remains a severe lack of suitable materials technology. This lack is apparent in two critical areas. First, production quantities of high-quality GaAs crystals, reproducibly doped and precipitate-free, simply are not available commercially, although some reasonable quality material is available on a limited first-come, first-serve basis. Second, in comparison to silicon technology, little is known about the effects of processing variables on the defects either present in as-grown GaAs or introduced through processing and handling of wafers. These areas are now receiving some attention from semiconductor device manufacturers, who are studying defects in GaAs in order to better understand how either to prevent their occurrence or to cope with their existence. Most investigations of the defects in GaAs have been made by optical microscopy3-5 or transmission electron microscopy techniques.&apos;-&apos; Recently, however, the imaging techniques of X-ray topography, electron mi-croprobe analysis, and scanning electron microscopy are being applied to the study of GaAs.9-14 In the case of X-ray topography, a one-to-one image is obtained that must be photographically enlarged. In compensa- tion, the defects within entire wafers may be imaged by simple scanning (Lang technique15) if the wafer is reasonably perfect, or by using the scan oscillation technique developed by Schwuttke16 if the wafer is warped or distorted. The purpose of this paper is to both review and extend the general application of X-ray topographic techniques to GaAs. Emphasis will be placed on the effects of growth and process variables on the quality and perfection of both bulk and epitaxial GaAs. Reference to optical or electron microscopy results will be made when useful. Since the effects on defects of a wide variety of processing variables such as crystal growing, sawing, polishing, diffusion, and epitaxial growth will be somewhat superficially reviewed, a fairly extensive bibliography of the most important recent results in these areas is included. However, for completeness, important defects will be illustrated here, although such defects have been previously shown by others. While this paper is concerned with defects rather than with the physics of X-ray scattering, the mechanisms of contrast formation in the topographs will of necessity be briefly mentioned. EXPERIMENTAL GaAs crystals, both boat-grown18 and Czochralski-grown,&apos;8 containing a variety of dopants of various concentrations, were purchased from outside vendors. Wafers were sliced from the crystals using a Hamco ID saw and were mechanically polished using 1 µ diamond paste. Chem-mechanical polishing was done in bromine-methanol as described by Sullivan and Kolb.18 Chemical polishing was done using a modified sulfuric-peroxide solution, 11 parts H2SO4, 1 part 30 pct H2O2, 1 part DI water.5 Zinc diffusion was carried out in a closed tube, using a 10 pct Zn-In source at 825°C for 1 hr. Oxide masking techniques were used to select the area to be diffused. Epitaxial wafers were either purchased or prepared here. All epitaxial runs prepared here were carried out using a Ga-GaAs-AsC13 source in a closed tube at a substrate temperature of 750°C. Wafers were chem-mechanically polished and gas-etched prior to deposition. The X-ray topographs were taken on a Krystallos Lang camera, operating in the transmission scanning geometry (Lang technique15) or in the reflection scanning geometry (modified Berg-Barrett technique20,21). MoKa, radiation was used for all transmission topographs using a Jarrell-Ash 100-µ spot focus. CuKal radiation was used for all reflection topographs using a General Electric CA-7 1-mm spot focus X- ray tube. Topographs were printed from an intermediate contrast inversion film, so the contrast shown in all figures here is the same as that of the original 50-µ-thick emulsion L4 Iiford nuclear plate used to record the topograph.

Jan 1, 1969

THE Institute assembled in the Hall of the Boston Natural History Society on Tuesday evening. Dr. T. Sterry Hunt, of the Boston Institute of Technology, after a brief address of welcome to the Institute, read an introductory paper on the Geognostical History of the Metals. President Raymond responded to the welcome of Dr. Hunt. The following names were then presented to the Institute, with the recommendation of the Council, for election: Adams, J. M., . . . . . . Silver City, Idaho. Daggett, Ellsworth,. . . . . Salt Lake City, Utah. Geist, Alfred W., . . . . . Boston, Mass. Hays, Dr. S. Dana, . . . . . Boston, Mass. Heinrich, Oswald J., . . . . Midlothian, Va. Johnson, J., . . . . . . Braidwood, Ill. Leckie, Robert G., . . . . . Actonvale, Canada. Lyman, Edward, . . . . &apos; . Troy, N. Y. Maltby, William, . . . . . Braidwood, Ill. Nichols, Lyman, Jr., . . . . Bbton, Mass. Ordway, Prof. J. M., . . . . Boston, Muss. Rand, Theodore D , . . . . . Philadelphia, Pa. Richards, Prof. Robert H., . . . Boston, Mass. Roclrwell, Prof. Alfred P., . . . Boston, Mass. Roepper, Charles W ., . . . . Bethlehem, Pa. Schulz, A. von, . . . . . Central City, Colorado. Singer, William F., . . . . Pittsburgh, Pa. Spillsbury, E. G., . . . . . New York. Wells, Calvin, . . . . . . Pittsburgh, Pa. The session concluded with the reading and discussion of a paper, by Henry Engelmann, On the Mines and Ores of the Little Cottonwood Canyon, Utah. The second session was held on Wednesday morning, when the following papers were presented : On the Midlothian Coal Mines, by Oswald J. Heinrich. On the Probable Existence of Microscopic Diamonds in California, by Prof. Benjamin Silliman.

By E. G. Deane

THE CHAIRMAN (P. G. BECKETT, Globe, Ariz.).-The mining of large orebodies has in the last few years been such a big factor in the copper output of this State, and, in fact, of the whole country, I feel that we should have some valuable discussion this evening on the various mining methods described in the papers which are to be read; and I hope you will start a discussion on Mr. Deane&apos;s paper. J. A. EDE, La Salle, Ill.-I would like to ask whether, the timbers being left in, they have any fires owing to that fact? E. G. DEANE.-No, we do not. The timbers in the mat seem to lose life. I cannot tell you exactly what change takes place, but they do not burn readily. There is undoubtedly a chemical change in them-a change that makes them lose all strength. I , spoke of the strength of the sills. When we first started, we put in 4 by 8 sills, but those sills had no more strength in 6 months than a 2-in. plank would have. .J. P. HODGSON, Bisbee, Ariz.- I would like to ask Mr. Deane if the central supply raise in the- center of the block has been satisfactory; and also whether in extracting the ore they put small raises up so that wheelbarrows are not used in the stope?

Jan 12, 1916

By C. H. White

Discussion of a Paper by Mr. C. H. White, read at the Atlantic City Meeting, February, 1904. (Annual Meeting, February, 1005.) ARTHUR JARMAN, Sydney, New South Wales, Australia (communication to the Secretary*) : All designs for modern metal¬lurgical and chemical laboratories should provide each student&apos;s desk with a hood or cupboard for the removal of fumes, but I doubt the advisability of placing air-baths and similar apparatus close to the hot plate. It seems to me that unless the draft be exceptionally strong the fumes from ordinary wet assay work will corrode the iron-work of the fittings, in which case the baths would have to be removed to a general desk in order to lighten the work of the laboratory attendant. Since the laboratory described by Mr. White has been in use for two years, I should like to ask if any inconvenience has resulted from this corrosion. If not, it is certainly an important improvement to have the air-baths and similar apparatus placed -on the student&apos;s desk. The hoods described by Mr. White are supplied with a good draft by means of a fan, which gives them a great advantage over those at the metallurgical laboratory at the University, Sydney, in that no doors to the hood are needed. Each hood in the laboratory at Sydney is connected by a glazed earthenware drain-pipe with a vertical flue, 20 ft. high, having a lighted gas jet at the bottom to assist the draft. Although the draft is good, fumes of sulphuric acid cannot be drawn o$ unless the doors of the hood are lowered more than half-way. In my opinion, a fan should be used for the purpose of creating the draft, and glazed drain-tile should invariably be used for the flues because no other material possesses the same advantages. I know of a recent instance in which a laboratory containing

Mar 1, 1905

By Pierre R. Hines

Diphenyl guanidine is used as an accelerator in vulcanizing rubber. Other rubber accelerators are also flotation collectors, e.g., dithiocarbamate, thiazole, and the xanthates. Urea and its derivatives are good flotation collectors,1 and guanidine is the nitrogen analog of urea. These two characteristics suggested testing diphenyl guanidine as a flotation collector. Diphenyl guanidine has been tried in flotation work previously, but references give no details.2-4

Jan 2, 1959