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By E. F. La Vigne

ON Aug. 10, 1884, the Retsof Mining Co. began the sinking of an 18 by 12-ft. shaft at Retsof, N. Y. Rock salt was reached in 1885, in September, at 1008 ft. below the surface. The first salt was shipped in the fall of 1885. A timber breaker was built in 1886. In July, 1895, there was a consolidation of the Retsof Mining Co., the Greigsville Salt & Mining Co., the Livonia Salt Co., and the Lehigh Salt & Mining Co. These consolidated salt companies are now known as the Retsof Mining Co., a subsidiary of the International Salt Co. Eventually all of the mines were closed except the mine of the Retsof Mining Co., at Retsof, Livingston County, New York. On July 6, 1921, about ½ mile south of the original shaft and plant of the Retsof Mining Co., a new 9 by 28-ft. concrete-lined shaft was started. The shaft is 1063 ft. deep from the top of the shaft collar to the bottom of the salt bed. At the same time a reinforced-concrete breaker and other buildings were erected. This new plant began opera-tions on Dec. 15, 1923. It was designed for a capacity of 3000 tons in 8 hours.

Jan 1, 1936

By J. M. Tobin, L. H. Cadoff, L. M. Adelsberg

The reaction between liquid zirconium and graphite at temperatures above 2000 °C has been investigated. The reaction products were found to be carbon-saturated zirconium metal and ZrC which formed between the graphite and the metal. Parabolic growth behavior was observed for the ZrC Phase at all temperatures of this investigation. The parabolic growth constant at temperatures between 2000° and 2860°C was measured to be 1.83 exp 84,300/RT) sq cm per sec. The reaclion mechanism was proposed to be the rapid carbon saturation of the liquid metal and the formation of ZrC at the metal-carbide interface with diffusion of carbon through the ZrC, the "rate - determining step" of the reaction. The concentration-independent diffusion coefficient of carbon in ZrC, (DZrC), was expressed as 0.95 exp? 78,700/RT) sq cm per sec. This value mas calculated using the temperature-invariant ZrC phase fields proposed in the literature. The [ZrQiq)] — [ZYQiq) + ZrC] phase boundary over the temperature range 2000° to 2800°C was determined and the ZrC + C eutectic temperature was found to be 2890° ± 50°C. ThE Group IV and VB transition-metal refractory carbides are of interest because of their high melting points, high temperature strength properties, and relative inertness in certain corrosive environments. The present-day understanding of these materials, however, is limited by the general unavailability of accurate and reliable physical and chemical property data. This is due primarily to the difficulties associated with the preparation of suitable, high-density, high-purity carbide samples, and the achievement and control of uniform high-temperature environments. Accurate measurement of temperature is also an important factor limiting the reliability of reported data. The Zr-C reaction was selected for investigation because of the high melting point (>34000C) and favorable nuclear properties of the reaction product, ZrC. The direct reaction method afforded an opportunity to obtain kinetic data on the fully dense carbide. In this paper, layer-growth techniques were used to estimate the diffusivity of carbon in ZrC and to investigate the phase equilibria in the Zr-C system at temperatures above 2000°C. EXPERIMENTAL PROCEDURES AND DATA Crystal bar zirconium (99.9 pct Zr), purchased from the Nuclear Materials and Engineering Corp., and ZTA graphite (99.9+ pct) were used in this study. The analyses of the materials are listed in Table I. A schematic of the high-temperature carburization apparatus is shown in Fig. 1. The sample was a zirconium metal charge in a 1/2 -in.-ID graphite crucible which was capped with a tightly fitting graphite stern. The crucible and stem were designed to closely approximate black-body conditions. The graphite crucible was packed in lampblack (outgassed 1 hr at 2100°C) which provided insulation and thermal stability to the system. The inert atmosphere was maintained by a constant flow of high-purity argon or helium gas. The nozzle-diffuser section on the top flange was sufficient to prevent back-diffusion of air into the system. Chemical analysis of the carburized samples revealed oxygen and nitrogen concentrations of less than 44 and 20 ppm, respectively. The sample was heated by induction with a Westing-house 5 kw-450 kc power source. Temperature was measured with a Milletron two-color pyrometer which was sighted into the crucible by reflection from an overhead front surface mirror. Optical losses due to glass absorption and light reflection at air-glass interfaces were minimized by the employment of the dynamic-gas seal. It was found that no correction was required for the front surface reflector. The pyrometer was calibrated periodically against a U.S. Bureau of Standards tungsten ribbon secondary standard. Temperatures inside the crucible were also calibrated against the Zr-ZrC eutectic (1850°C)1 and the Nb-Nb2C eutectic (2335°C)2,3 temperatures and agreed to within ±10°C of these values. The temperature was controlled by manually adjusting the power input; variations of

Jan 1, 1967

The first mention of the mining and use of coal in the Pittsburgh district refers to the mine under Duquesne Heights that furnished coal for the garrison at the fort at Pittsburgh in 1760. Coal had been dug and used as fuel just outside of Brownsville, Fayette county, in 1759, but this was not a regular mine as the opening was in an outcropping. Maps of Ohio in 1770 showed "Cole Mines" at various points. The Penns purchased all the coal south of Kittanning in southwestern Pennsylvania from the Chiefs of the Six Nations for a reported price of $10,000. During the Revolution, coal from Herron Hill, Mincrsville, and Coal Hill, all within the present city limits, was used in Pittsburgh. There is today one custom pit opened in Coal Hill (Duquesne Heights). The first steam engine was set up in Pittsburgh in 1794 and used coal as fuel. The first mine in the Youghiogheny gas district was opened in 1796. In 1803, the first shipment of coal by water was made from Pittsburgh down the Ohio river and landed at Philadelphia, where it sold for approximately $9.50 per ton. The mines along the Monongahela were naturally the first to be opened. With the completion of locks and dams in 1844, permitting slack-water navigation, the industry began to thrive. The No. 8 field of Ohio and the Fairmont region of northern West Virginia were opened in the period 1840 to 1855. From that time on there has been a continuous development of the coal rcsources of this district, until at present productive capacity is enough to supply 30 per cent. of the country's needs of bituminous coal. The original method of working the Pittsburgh seam was to drive under cover at some easily accessible point on the outcrop with a single entry, usually 1½ yd. wide. Rooms or gangways were turned to the right and left from this entry and ventilation was usually poor and inade-

Jan 1, 1927

THE first mention of the mining and use of coal in the Pittsburgh district refers to the mine under Duquesne Heights that furnished coal for the garrison at the fort at Pittsburgh in 1760. Coal had been dug and used as fuel just outside of Brownsville, Fayette county, in 1759, but this was not a regular mine as the opening was in an outcropping. Maps of Ohio in 1770 showed "Cole Mines" at various points. The Penns purchased all the coal south of Kittanning in southwestern Pennsylvania from the Chiefs of the Six Nations for a reported price of $10,000. During the Revolution, coal from Herron Hill, Minersville, and Coal Hill, all within the present city limits, was used in Pittsburgh. There is today one custom pit opened in Coal Hill (Duquesne Heights). The first steam engine was set up in Pittsburgh in 1794 and used coal as fuel. The first mine in the Youghiogheny gas district was opened in 1796. In 1803, the first shipment of coal by water was made from Pittsburgh down the Ohio river and landed at Philadelphia, where it sold for approximately $9.50 per ton. The mines along the Monongahela were naturally the first to be opened. With the completion of locks and dams in 1844, permitting slack-water navigation, the industry began to thrive. The No. 8 field of Ohio and the Fairmont region of northern West Virginia were opened in the period 1840 to 1855. From that time on there has been a continuous development of the coal resources of this district, until at present-productive capacity is enough to supply 30 per cent. of the country's needs of bituminous coal. The original method of working the Pittsburgh seam was to drive under cover at some .easily accessible point on the outcrop with a single entry, usually 1 1/2 yd. wide. Rooms or gangways were turned to the

Jan 10, 1926

By John Wulff, J. H. Hollomon

THE opinion has been widely held that the corrosion of alpha brass occurs by the selective solution of zinc. As late as 1939, Fink1 and Evans2 suggested that in the initial stage of the corrosion the selective solution of zinc produces copper-rich areas, which subsequently act as cathodes that facilitate the deposition of copper. Previously Abrams3 had shown that most of the copper found on corroded brass was redeposited and not residual, although he did not consider the nature of the initiation of the corrosion process. Enough data exist to indicate that any metal surface is sufliciently heterogeneous to provide the anodes and cathodes necessary for the initiation of corrosion .4,5 Thus, for alpha brass we need postulate not an initial selective solution of zinc, but only the existence of local differences in electrochemical potential. The heterogeneity responsible for potential differences may arise from oxide and other films as well as from alloy concentration gradients. Even though selective corrosion may be possible in some alloy systems, previous data on alpha brass as well as the experimental work reported in this paper do not require this supposition. Bengough and May,6 in a discussion of Abrams' paper, first suggested the addition of small amounts of arsenic (0.03 per cent) to alpha brass to prevent the redeposition of copper (dezincification). This suggestion was later substantiated by Nixon.7 In their studies of the inhibiting influence of arsenic, Evans and Fink were led to the selective-solution hypothesis in order to explain the initial corrosion of such alloys. "I hey believed that an arsenic film covered anode areas and prevented the formation of copper-rich spots capable of acting as cathodes for the deposition of copper. They (lid not consider, however, the mechanism by which the arsenical film was formed. Bengough and May,8 in another publication, suggested that the commonly found gray or black arsenical film may act to: (1) carry oxygen to the brass surface, (2) increase the discharge potential of copper on brass, (3) precipitate cuprous chloride from colloidal suspension in chloride solutions. Masing9 assumed that the film found upon arsenical brass was metallic arsenic. His measurements of hydrogen overvoltage of bulk arsenic led hint to believe that the inhibition of dezincification occurs because the overvoltage of a brass surface is lowered by the arsenic film. He reasoned that this film would permit the more rapid reduction of hydrogen at the cathode, which would prevent the redeposition of copper. In a recent paper,10 we have pointed out that the film formed (luring the corrosion of arsenical brass and copper in stagnant solutions is essentially arsenious oxide (AS208)

Jan 1, 1942

US 4,192,851-Recovery of elemental sulfur and the metal values from a complex sulfide ore containing two or more of the metals zinc, lead, copper, silver, gold and/or other metals. A mixture of ore and sulfuric acid and/or spent electrolyte is flowed at optimum temperature and pressure in a quiescent zone to dissolve selected metals and sulfur and coalesce the sulfur. The coalesced sulfur and unreacted sulfides are separated by flowing the leach slurry with an upward velocity component The separated materials are discharged and further processed by conventional methods as war- ranted. H.E. Hirsch, J F. Higginson, EG. Parker, and G M Swinkels, assigned to Sherritt Gordon Mines Ltd. Mar. 11, 1980. 6 pp. (423-28) Filed. 3-14-78 (886,368). Priority. United Kingdom, 3-15-77 (10800/77).

Jan 1, 1982

By S. G. Epstein

Electromigration has been measured in dilute liquid alloys of lead in antimony and antimony in lead. In these alloys antimony migrates with the electron current; lead migrates in the opposite direction. These results, which contradict the mass criterion, were predicted by the electron drag model for electromigration in liquid alloys. The existing experimental data are shown to correlate with the difference in electrical resistivities of the alloy components. FOR many years investigators have attempted to relate observed electromigration phenomena in liquid alloys to the physical properties of the alloy components. The most successful correlation was found by Angus et' al.,1 who in 1959 proposed an empirical criterion for predicting the relative direction of motion of the components of a liquid alloy in an electric field: the component with the smallest atomic mass concentrates at the cathode. While this criterion is obeyed in nearly all the alloy systems which had been investigated, the physical basis for such an effect was not understood. It was also disturbing that the mass criterion predicted the wrong sign for the Haeffner effect; observations with pure liquid metals revealed that in every instance the lighter isotope was transported to the anode.2 Klemm3 explained these isotopic separations by suggesting that the lighter isotopes were more mobile and more easily carried to the anode with the electron stream. Additionally, several deviations from the mass criterion have been found in liquid alloys, notably involving transition metals such as chromium, nickel, palladium, and zirconium, which migrate to the anode in liquid bismuth.4'5 Recently, a model has been proposed6 in which electromigration in liquid alloys is attributed primarily to the interaction between the electron stream and the metal ions. In essence, this model predicts that the component with the greater electron-ion scattering cross section will be preferentially transported to the anode, displacing the other component to the cathode. The electrical resistivity of each pure component at its melting point is taken as the measure of its scattering cross section. This model was developed from the results of systematic studies with various solutes in liquid mercury,7'8 bismuth,9 and sodium.10 In every alloy, the component with the greater resistivity has centrates at the anode. Coincidentally, in every instance the component with the greater resistivity has also the greater mass, apparently satisfying the mass criterion. In order to differentiate between electron-ion coupling and atomic mass as the relevant physical prop- erty influencing electromigration, measurements were made with Pb-Sb alloys. Lead has an atomic mass nearly twice that of antimony, but lead has an electrical resistivity of 91 microhm-cm while antimony has a value of 113.5 microhm-cm at their respective melting points. The mass criterion predicts that in an alloy of the two antimony will concentrate at the cathode; the electron drag model predicts that antimony will concentrate at the anode. EXPERIMENTAL To conclusively determine the relative motion of lead and antimony in each other, solute electromigration was measured in dilute liquid alloys of antimony in lead and lead in antimony. Both starting materials were 99.999+ pct pure. The measurements were made with the same capillary-reservoir technique previously used for measuring electromigration in liquid bismuth alloys.11 Several changes in the experimental apparatus were necessary, however, to accommodate liquid antimony, which has a higher melting point than bismuth. The modified apparatus is depicted in Fig. 1. In each experiment four quartz capillaries were filled with the molten alloy. A direct current was passed through two of the capillaries; the electrode in one of these capillaries was made the cathode, and the electrode in the other was made the anode. The remaining two capillaries sampled the alloy in the reser-

Jan 1, 1969

By Edward Gridley

Members of the Institute who were present at the Amenia, N. Y., meeting, in October, 1877, will remember their visit to the hematite mines, just west of the village of Amenia, and some of them may perhaps recall the deposit of carbonate ore south of the opening made for the hematite. The smelting of this carbonate during the last few months, has produced an iron that seems worthy of being brought to your notice. A little more than a year ago, at the Wassaie Furnace, Dutchess County, N. Y., we made a few hundred tons of iron from a mixture of two-thirds ram carbonate and one-third Chateaugay ore, hoping that it would be suitable for steel purposes, but as the iron showed phosphorus 0.189 per cent., it, was not offered. This iron looked well and seemed quite strong, and gave good results in malleable castings; but no special tests of strength were made. About February 1st, of this year, we began using two-thirds roasted carbonate, and one-third Chateaugay, and noticing that the iron mas stronger than usual, we had two samples tested, which showed tensile strength of 32,014 and 34,176 pounds per square inch. After our stock of Chateaugay ore was exhausted, me put on one-third ram carbonate with the two-thirds of roasted carbonate, and the first test made of the iron, showed 40,008 pounds per square inch. The three tests given above were made by Mr. A. J. Copp and Mr. E. B. Manning, of the Phoenix Furnace, Millerton, N. Y., on a machine of Riehle Bros., Philadelphia. Since these tests were made, they have broken samples made with all carbonate ore as follows: 39,669, 40,816, 41,882, 42,281, 39,902, and 40,130 pounds per square inch. A test taken from the same bed of iron as the last-mentioned (40,130), was broken by Mr. A. Blass, at Irondale Furnace, showing 40,151 pounds per square inch. A sample broken on the Riehle Bros. machine, at Stevens Institute, under direction of Professor R. H. Thurston, showed 40,000 pounds per square inch. Another sample was broken by Professor Thurston on his torsion machine, and gave torsion 7", and tensile strength of 44,500 pounds. And

Jan 1, 1884

By Francis A. Thomson

IN reviewing mineral industry education a year ago, occasion was taken to congratulate the Institute in general and to felicitate the Education Di- vision in particular on "the most gratifying growth which is taking place in Institute consciousness in regard to its responsibility for the recruitment and adequate training of student personnel and for the successful bridging of the difficult gap between graduation and achievement of professional status." Continuation of this growth of interest throughout 1939 is a recognition of the validity of the splendid statement of George Otis Smith that the mining students of today are the ore reserve of the Institute for the future. In this connection one recalls the equally apt expression of another distinguished geologist, George M. Fowler, who, speaking of exploration for ore deposits, says, "The place to look for elephants is where elephants have been found."

Jan 1, 1940

Richard Moldenke, New Pork, N. P. (communication to the Secretary*):—Iu following the discussion of the specifications for cast-iron and finished castings, I mas strongly impressed with two points which might be ventilated to advantage more fully from the view of the practical foundry-man. First, the reasons why only silicon and sulphur were specified and not phosphorus, manganese and carbon; and second, why but little was said concerning the presence of iron oxide in the material.

Jan 1, 1905

By C. S. Roberts

Four binary alloys in this system were creep tested at 300°' to 600°F. A photographic study of microstructural changes showed that the outstanding creep resistance results primarily from a potent precipitation hardening locally at grain boundaries. Twinning was correlated with the primary stage and nonbasal slip with the tertiary stage of creep. THE utility of the rare earth metals as ingredients of magnesium alloys destined for elevated temperature application has been recognized for about 15 years. A review of the early development of these alloys has been given by Leontis. 1,2 It has been only recently that a desire has arisen to understand basically their remarkable creep resistance. The present research had that object. The work of Leontis showed that the differences between the behavior of the individual magnesium-rare earth element binaries was of commercial significance. However, the variations were small compared to the overall difference in creep resistance between the group as a whole and the magnesium alloys of the Al-Zn type. It was decided to conduct this investigation with one binary system which would be representative of the magnesium-rare earth element alloy group. Cerium was chosen as the solute because of its near-middle position in the series and because of its availability in the commercially pure form. A previously published description of the creep behavior of electrolytic magnesium" serves as the background to this research. The experimental approach used in that investigation has been partially repeated here. A series of binary alloys was planned to include the following: 1—A dilute alloy which would contain the cerium almost entirely in solid solution. This would assess the solid solution effect. 2—An alloy which is nearly saturated at the selected solution heat treatment temperature, 1070°F. Here the effect of nearly maximum precip- itation would be obtained without the influence of undissolved Mg-Ce intermetallic. 3—An alloy containing slightly more cerium than is soluble at 1070°F. This would allow the investigation of the effect of a small amount of excess intermetallic. 4—A high cerium alloy in which the influence of a large volume of undissolved intermetallic may be examined. Experimental Details In order to specify compositions of the binary alloy series a knowledge of the solubility of commercially pure cerium in solid electrolytic magnesium and also of the composition of the terminal intermetallic phase was necessary. The latter has been proven to be approximately Mg,Ce by Voge14 and Haughton and Schofield.5 A series of both cast and extruded alloys were solution heat treated 24 hr at 1070°F for a solubility determination. Lineal analyses of the polished and etched microstructures were accomplished with the aid of a Hurlbut

Jan 1, 1955

By Yves Dardel

The literature concerning the remelting of alunlinum and its alloys is very rich. Unfortunately the majority of the papers on this subject have no scientific value, for the theories or explanations are too often in opposition to the laws of physical chemistry. Furthermore only a few of the methods of purification are considered in the literature. Hence it has seemed necessary to the author to sketch a general theory of the purification of secondary aluminum. The purpose of the purification is to eliminate the impurities that the charges, and the atmosphere of the furnaces bring into the bath during the successive remelt-ings. Indeed scrap as well as metal can be used when soiled with oil, greases, water, or others, if it has been sufficiently dried and contains oxides. At the melting point of the metal, the oils and greases are decomposed into their constituent elements H², O2, H²O, co², CO, CH,, and others. These gases are added to the corresponding gases in the atmosphere of the furnace. The impurities introduced into the metal during the remelting will accordingly be the products resulting from the action of these gases on the liquid bath. The quantity of hydrogen that is soluble in aluminum and its alloys is given by the relation of sieverts3 as a function of its partial pressure PH2 in the atmosphere m = K vPH² [I] where K is a constant, which depends only upon the temperature and increases with it. The experiments of Rijntgen and Braun4, RÖntgen and M611er5, Bircum-shaw6 and Winterhagerl have rendered it possible to determine the value of K, when the temperature is less than 1.000°C. One obtains: log K = - 4,702.5T + o 238 [2] Besides its usual significance, the term Ph~ represents also the internal pressure of dissolved hydrogen, since in the equilibrium, that is1 when no gas exchange Occurs between the two phases, the Pressures of hydrogen in the metal and in the atmosphere must be equal. Eq I shows that when the partial pressure of H2 increases the amount of dissolved hydrogen in equilibrium increases, and that, if the contrary Occurs, the quantity of H² should diminish. However, if for any reason the diffusion of hydrogen is hindered and the total amount of dissolved gas remains constant while the temperature decreases, the internal pressure of H² increases until it reaches the value of the hydrostatic pressure. At this point, bubbles of hydrogen appear in the bath and escape out of it. The amount of hydrogen in the metal is then limited by a a depending On the hydro- static pressure, which is practically equal to one atmosphere. Indeed hydrogen does not accumulate in the form of a hydride appearing as a separate solid phase. However1 even the mechanism of the solubility is not yet elucidated. One does not know exactly as yet, whether the

Jan 1, 1949

By E. W. Wagy

The year 1927 witnessed numerous developments of significance in California. The State's shut-in production increased from an average of 58,000 bbl. daily in January to a maximum of 93,000 bbl. daily in August, and a total of about 25,000,000 bbl. was withheld from the market during the year. This not only lessened the effect of large production at Hunt-ington Beach, Seal Beach and Alamitos Heights, but also was a most effective conservation move. Since 1922, it is estimated that approximately 100,000,000 bbl. of oil that would otherwise have been produced have been held in the ground. I. Outstanding Field Developments of 19271 1. Long Beach Deep Sand. 2. Rincon (Seac1iff)Discovery. 3. Alamitos Heights Discovery. 4. Ventura Avenue Extension. 5. Round Mountain Discovery. 6. Mt. Poso Extension. 7. Potrero (Cypress) Discovery. 8. Buttonwillow Gas Development. 9. Goleta Discovery. 10. Union Avenue, Edison and Fruitvale Areas. (See Fig. 1.) II. Crude Production The most important factor in new crude production in 1927 was the Seal Reach field with its adjacent Alamitos Heights townlot area. Production increased from about 10,000 bbl. daily in January, to a peak of 66,000 bbl. in June. Huntington Beach finished the year 1926 with a production of 102,000 bbl. daily, which declined to 60,000 bbl. by the end of 1927. Due to production in these three areas and the tempering effect of shutting in numerous wells, the California production curve for 1927 was held at a fairly even level. Fig. 2, shows the State's production in 1927 and 1926 as compared with 1923, which was the year of excessive

Jan 1, 1928

By S. H. Ash

Safety records in the mineral industry for 1954 will do well to hold their own as compared with 1953, because of the poorer rate in the coalmining branches, even without the recent mine explosion at the No. 9 mine of the Jamison Coal & Coke Co., Farmington, W. Va., that killed 16 persons. .The cause of that disaster has not yet been ascertained. The metal-mining branch appears to have improved its record over the last year, however. Health Diesel equipment continues to be favored in non-coal mines. Equipment includes locomotives, trucks, tractors, and muckers. Of major concern and interest is the establishment of a new threshold limit for oxides of nitrogen-5 ppm as compared with 25 ppm. This gas is the most harmful component of diesel-engine exhaust gas

Jan 3, 1955

By George B. Lee

During the two years in which the new reduction-works of the Copper Queen Consolidated Mining Co. have been in operation at Douglas, Ariz., there has developed a remarkable condition in regard to the corrosive action of the water used to cool the jackets of the blast-furnaces. Were it not for the many contradictory features, it might pass as one of the unavoidable troubles due to the composition of the water. This water, obtained from wells 600 ft. deep, is also used in the steam-boilers, and its composition, as shown by the following analysis, does not indicate the presence of any ingredient which would explain the corrosion: Grains Per U. S. Gal. Silica,...........0.861 Iron oxide and alumina,....... 0.223 Calcium carbonate,....... 0.261 Calcium sulphate,................. Magnesium carbonate,........... Sodium and potassium sulphates,..14.850 Sodium and potassium chlorides,.9.732 Sodium and potassium carbonate, . 6.482 32.409 The jackets are made of inner plates 0.5 in. thick and an outer plate # in. thick, with 3/8-in. stiffeners between the inner and outer plates. In from 10 to 12 months the inner plates have been reduced by corrosion to a thickness of from + to & in., while the outer plate in the same time is reduced by less than 1/16 in., and the stiffeners show very little corrosion. The plates are pitted and eaten away in some places more than in others. There is practically no scale found on the jackets, but when cleaned considerable iron oxide is found in the bottoms. With an action so marked, serious trouble would be expected in the boilers, but, on the contrary, a recent inspection by a

Jan 1, 1908

By F. Claisse, R. Angers

Self-diffusion in iron has been measured during rapid a-r transformations using a variant of the Kryukou and Zhukhovitskii diffusion method. The study was performed by thermally cycling iron foils (1 to 6 cpm) through the transformation (=910°C). Some foils have been subjected to over 1000 cycles and some have spent more than 15 pct of their total diffusion time in the process of transformation. The experimental results show that the a-r transformation has no measurable effect on self-diffusion in iron. The study is completed by a quantitative analysis of mechanisms which can affect the diffusion rate during the transformation. The analysis confirms the experimental results. SINCE diffusion is an important factor in many solid-state transformations, it is of interest to study how it is affected by the stresses generated during these transformations. Clinard and Sherby1'2 were the first to make a study along these lines. They measured diffusion coefficients in Fe-FeCoV couples subjected to slow thermal cycling (1.5 cph) through the a-r transformation range. They found an enhancement of diffusion by a factor of about two. The purpose of the present paper is to report measurements of the self-diffusion coefficient of iron during much more rapid thermal cyclings (1 to 6 cpm) through the a-r transformation (-910°C). These more rapid cyclings produce higher strain rates during the transformation and should emphasize any possible influence of transformation upon diffusion. EXPERIMENTAL Iron foils, 25 to 35 µ thick, were cold-rolled from 99.92 pct pure iron and annealed in pure helium for 2 hr at 870°C; the resulting grain diameter was about 150 µ. Specimens 0.5 by 8 cm were cut from the foils and I7e55 was vapor deposited on one of their surfaces. A 38 gage alumel-chrome1 thermocouple was spot welded in the middle of one of the specimen long edges, Fig. 1. Two 38 gage chrome1 wires were also spot welded along the same edge on each side of the thermocouple; they were placed 2.5 cm apart and used for electrical resistance measurements. In order to prevent twisting and crumpling, the specimens were pinched between two quartz plates 0.1 by 1 by 7 cm and the assembly was close fitted into a 1 cm ID quartz tube. Four holes were drilled through the tube to let the 38 gage wires out: these were connected to the recording equipment by means of extension wires. 20-gage nickel wires fixed at both ends of the specimens were used to thermally cycle the foils by Joule heating. The above described device was placed in a 2.7 cm ID quartz tube which in turn was placed in a tubular furnace. Either a pure helium atmosphere or circulating hydrogen was used during the experiments. Specimens were subjected to thermal cycles between a minimum temperature To and a maximum temperature Tm at rates ranging from 1 to 6 cpm. This was obtained by maintaining the furnace at a constant temperature near the minimum temperature To and periodically passing an electric current through the specimen. Cooling was achieved by heat losses to the surroundings. The forms and periods of cycles were varied from one specimen to another; however, each specimen was subjected to one type of cycle only. The temperature and electrical resistance variations of the specimens were recorded as a function of time. The temperature curves were used for diffusion calculations while the electrical resistance curves were used to monitor the transformation and to determine its starting point and its approximate duration. Diffusion was measured by the method developed by Kryukov and zhukhovitskii3 and modified by Angers and Claisse.4,5 In this method a metallic foil is coated on one side with a radioactive isotope and the activity is measured periodically on both sides during the diffusion anneal. The following equation then holds: where: I1 Activity on the surface on which the deposit is made. I, Activity on the opposite surface. t Diffusion time. B Constant. D Diffusion coefficient. d Foil thickness including the deposit. G(t) A function of time; it is a second order correction term which is given graphically in Refs. 4 and 5. The diffusion coefficient D is found by plotting ln[(Il - I2)/(I1 + I,)] -G(t) against t; the resulting slope m leads to an accurate calculation of D through Eq. [2]. The effect of the a-r transformation on diffusion is expressed by the ratio DT/DU where:

Jan 1, 1970

By F. N. Speller

Interest in the corrosion problem seems to continue without abatement and is bringing practical results. At least four important conferences on this subject have been held during the last 5 months. Those interested in steel-frame structures are taking steps to study vulnerable points on account of the failure of some minor parts in certain buildings after 35 years of service. The steam power-plant group, including the railroads, realize the importance of a better knowledge of corrosion, especially under modern high-temperature boiler operations. The chemical and refrigerating industries have already conducted a systematic study of depreciation of metals by corrosion, for which they have spent considerable money and time during the last 2 years with encouraging results. More has probably been done to control corrosion in the atmosphere and in closed water systems, because the work on these phases of the problem started over 15 years ago and the important factors are now fairly well understood. As a result of all this work, there is now little excuse for corrosion in water conduits, recirculating condensers and cooling systems, since economical means of prevention have been worked out to meet nearly all situations where such corrosion occurs. The entire Baltimore water supply was treated with lime at a cost of only 35 c. per million gallons and the rate of attack on the pipes has been reduced to not over 20 per cent. of what it was before the treatment. Yearly damage to water mains in Baltimore is estimated at $300,000, and in New York City at $5,000,000, not including damage to water conduits in buildings. In some cities corrosion is now recognized by water works' engineers as a major problem. In the oil industry, there are evidently three general classes of corrosion, relating to: (I) Production, (2) transportation, and (3) refining. (1) Production.—Some fields, those of California for example, have little corrosion trouble in the wells. In others this is a major problem and should be a strong incentive to the development of more resistant metals at a reasonable cost. E. G. Woodruff,' consulting geologist, has pointed out that more of the oil of the future will probably come from the

Jan 1, 1927

By W. V. Green

Creep of tantalum was measured at temperatures from 0.6 to 0.89 of the absolute melting temperature. The creep curves include first, second, and third stages. Steady-state creep rate depends on the fourth power of stress. The activation energy for creep throughout this temperature range is approximately 114 kcal per mole, measured by the aT technique. Subgrain formation occurs as a result of creep strain, and pile-up dislocation arrays are observed in etch-pit patterns. BECAUSE of its high melting point-which is exceeded only by those of rhenium and tungsten—and its high room-temperature ductility compared to most of the other high-melting-point metals, tantalum will undoubtedly be utilized in an increasing number of high-temperature applications. Alloying studies directed toward increased high-temperature strength must use data on tantalum itself as a base line in order to evaluate the effectiveness of the alloying additions. However, to date, no systematic study of creep of tantalum at temperatures above one-half of its melting point has been reported in the literature. Conway, Salyards, McCullough, and Flagella1 have measured linear creep rate of tantalum sheet as a function of stress, but at only one temperature, 2600°C. This paper describes a relatively thorough study of the high-temperature creep of tantalum. METHOD Material Tested. The commercially supplied, l/2-innch-diameter tantalum rod used for this work was electron-beam-melted, cold-forged, rolled, swaged, cleaned chemically, and vacuum-annealed for 1 hr at 1000°C, all by its manufacturer. The vendor's analysis included 60 to 170 ppm C, 3.4 to 4.2 ppm H, 60 to 80 ppm 0, 15 ppm N, and a hardness ranging from 66 to 81 Bhn and averaging 76 Bhn. Creep eimens Used. Two creep-tested specimens are shown in Fig. 1. The 1/4 in.-diameter gage section was 3/4 to 1 in. long, and terminated either at shoulders 5 mils high or at 20-mil-diameter tantalum wires spot-welded to the circumference of the gage section. Both kinds of shoulders served equally well as fiducial marks for optical strain measurements. The spot welding did not alter the creep behavior in any detectable way; the 5-mil- high sharp shoulders did not result in any detectable localized effect on the strain. Before testing, each tensile bar was first mechanically polished -id then electrochemically polished according to the method referred to by Forgeng2 as the "Thompson Ramo Woolridge" method, which was suitable for tantalum after small adjustments of technique were made. Two tensile bars tested at low stresses had 1/8-in.-diameter gage sections and utilized only the weight of the bottom grip for the applied load. Although these diameters were smaller than were desired for other reasons, applied loads were known with high precision in the tests in which they were used. Testing Procedure. Two different constant-load creep-testing machines were employed, one of which has been described by Smith, Olson, and Brown.3 In both, the tensile bar is held vertically on the axis of a cylindrical tungsten tube or screen heater by threaded tungsten grips. The tensile bars and associated grips are heated by radiation from the incandescent heaters, which are heated by their own electrical resistance. Both testing machines use pins to hold the bottom grips in place. The load is applied to a tensile bar through hanging weights, a constant force-multiplication lever, a pull rod sealed to the chamber lid, and a top grip threaded to the pull rod at one end and to the tensile bar at the other. In one machine, the vacuum seal is a bellows with a low spring constant; in the other, the seal involves a rotating "0 ring". With the latter, rotation is converted to translation with a crank shaft, so that elongation of the tensile bar is accommodated with no change of tensile load. The incandescent tensile bar is viewed by an external optical system through slots in the radiation shields and heater, and an enlarged image is projected on a ground-glass screen. Gage-length measurements are made on this image with cathetometers on traveling microscopes. With regard to creep-test results, the two machines were identical. Thorium oxide coatings were applied to the threaded ends of the tensile bars, to prevent diffusion welding of the tensile bars to the grips during testing. Specimen temperatures were measured with an L. & N. optical pyrometer which had been calibrated against a standard carbon arc, and were corrected fir window absorption by calculation from the measured spectral transmittance of the quartz observation windows. Longitudinal temperature gradients in the tensile-bar gage length and temperature drifts during testing were detectable but small, and were estimated to be 10°C or less. Accuracy of temperature measurement was confirmed by comparing the temperature measured on the surface of a special

Jan 1, 1965

By Edward L. Vickers

The Pacific rim countries, comprising more than half the globe, represent a complex mix of developed and developing nations. The area comprises a large segment of the industrialized world. Within its boundaries are also found many of the world's greatest mineral resources largely concentrated in the less developed countries. The conflicting objectives of these developed and developing nations are giving rise to changes in the traditional patterns of world resource development. Powerful political and socio-economic factors affecting the world today are having a great bearing on natural resource developments in the Pacific basin. New forms of partnerships have been emerging in developing nations which have had a great impact on the mining com- munity, lending institutions, as well as political relations. The United States and Japan have been substantially responsible in the past for the development of natural resources in this area of the world. Their role, however, is undergoing significant metamorphosis. The rapidly changing economic and social environment in the developing countries is producing new tensions which affect future collaboration between producers and users of natural resources. To understand current problems, I believe, it is worthwhile to examine historical trends in this area which may help defining alternatives facing us in the future. In modern times the United States was the first country in the Pacific basin to start development of resources on a massive scale. It began with the major exploration of the mineral-rich west of the United States and extended significantly later into Latin America and Australia. In the early 1950's, Japan became a significant

Jan 1, 1976

Discussion of the paper of EDGAR L. NEWHOUSE, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin: No. 92, August, 1914, pp. 1801 to. 1806. G. C. RIDDELL, East Helena, Mont.-As nearly as I can recall at the present moment, there are only four or five large plants on the continent where the lead on charge is carried in the neighborhood of 40 per cent. These are at Herculaneum, Collinsville, and Federal, Ill.; Trail, B.. C.; and East Helena, Mont. Our object at the latter point is to smelt a maximum amount of Coeur d'Alêne lead sulphides in as compact and self-fluxing a charge as possible, and to this end we are now smelting a mixture that at times carries up to 42 per cent. lead. The monotony of producing the 7,000 tons of bullion shipped each month to. the Omaha and Chicago refineries is relieved somewhat by the fact that the 15,000 tons monthly of Coeur d'Alêne ores that are com-ing to us carry enough zinc to provide the one-half slag used with from 6.5 to 7.5 per cent. zinc clay after day. During the month of March, 1914, three lead furnaces in continous operation, each 136 in. long, averaged 249 tons per furnace clay, exclusive of coke and slag shells, which is smelting at the rate of 5.5 tons per square foot of tuyère area. The

Jan 11, 1914