Meteoric Irons Research Articles

Excellent mechanical properties of taenite in meteoric iron

Meteoric iron is the metal that humans first obtained and used in the earliest stage of metal culture. Advances in metallographic analysis techniques have revealed that meteoric iron largely comprises kamacite, taenite, and cohenite, which correspond to ferrite, austenite, and cementite in artificial steel, respectively. Although the mechanical properties of meteoric irons were measured previously to understand their origin and history, the genuine mechanical properties of meteoric iron remain unknown because of its complex microstructure and the pre-existing cracks in cohenite. Using micro-tensile tests to analyse the single-crystalline constituents of the Canyon Diablo meteorite, herein, we show that the taenite matrix exhibits excellent balance between yield strength and ductility superior to that of the kamacite matrix. We found that taenite is rich in nitrogen despite containing a large amount of nickel, which decreases the nitrogen solubility, suggesting that solid-solution strengthening via nitrogen is highly effective for the Fe–Ni system. Our findings not only provide insights for developing advanced high-strength steel but also help understand the mysterious relationship between nitrogen and nickel contents in steel. Like ancient peoples believed that meteoric iron was a gift from the heavens, the findings herein imply that this thought continues even now.

XLVIII. X-ray study of some meteoric irons

(1939). XLVIII. X-ray study of some meteoric irons. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 28, No. 190, pp. 497-519.

The structures of meteoric irons

The structures of meteoric irons

Rusting of a Meteorite

EVER since the largest of the meteoric irons found at Cranbourne, about thirty miles south-east of Melbourne in Australia, was extracted from the sand in which it had lain buried for numberless years, it has shown a pronounced tendency to rust. This large mass, which weighed about 3J tons, was presented to the Trustees of the British Museum in 1862. When first received, it was mounted on a turntable and was shown uncased. So rapid, however, was the rusting that within a short time it was decided to place it in a glazed case and keep the air within as dry as possible by means of frequently renewed supplies of lime. The effect was to slow up markedly the rate of rusting, but not to stay it altogether. It is estimated that more than 4 cwt. of rust has been removed from the meteorite since it reached the Museum. Arithmetically, therefore, it would appear as if the mass had a very long life before it, but it would have been nothing like so long because the lawrencite (ferric chloride), the cause of the mischief, is disseminated in seams and by expanding during alteration tends to split up the mass. Owing to the size and porous character of the meteorite, treatment by a surface coating which has proved so successful with other meteoric irons was out of the question.

Societies and Academies

LONDON. Mineralogical Society, Nov. 4 (Anniversary Meeting).—F. C. Phillips: On crystals of brookite tabular parallel to the basal plane. Small yellow-brown rectangular plates in heavy residues from Middle Jurassic sandstones of N.E. Yorkshire are shown by optical and X-ray examination to be brookite of normal optic orientation but unusual crystallographic habit, being tabular parallel to the basal plane. They are associated in the residues with brookite of normal habit, abundant anatase, and rutile.—T. Ito and T. Shiga: On scorodite from Kiura Mine, Bungo, Kiushiu, Japan. The mineral occurs as small dark-brown and green crystals associated with vivianite, fluorite, and quartz in druses in veins of arsenopyrite intruded into limestone. Chemical analysis on carefully selected material gives a result consistent with the formula FeAsO4 . 2H2O. Forms present are (001), (100), (01l), (120), (111), (201), (211), and (322). The crystals are orthorhombic with a: b: c= 0.865: 1: 0.972. The habit is pyramidal equidimensional. The 111 faces show abundant vicinal faces belonging to two principal zones {01¯} and {10¯}. W. Campbell Smith: On a new meteoric stone from Suwahib, Arabia. The stone was found in 1930 on the sand near Buwah, in Suwahib, by one of the Arabs accompanying Mr. Bertram Thomas on his journey across the Rub' al Khali. As found, it weighed just over 2381/2 gm. It is coated with limonite and shows no definite crust. It is a black chondrite belonging to Prior's Cronstad type, with more than ten per cent of nickel-iron. The density is 3.52.—Edward S. Simpson and D. G. Murray: A new side-rolite from Bencubbin, Western Australia. A mass weighing 119.5 lb. (54 kgm.) was found in 1930 near Bencubbin, about 150 miles north-east of Perth. It consists of a skeleton of nickel-iron (68.8 per cent) with enclosed crystals up to 1 cm. across, of greyish-white enstatite (13.5 per cent) and dark olivine (12.5 per cent). In the metallic portion Fe: Ni =15:1. The meteorite is classed as a mesosiderite with an unusually high proportion of nickel-iron.—A. R. Alderman: The meteorite craters at Henbury, Central Australia. The locality is known locally as the Double Punch-bowl, from the two largest adjoining craters. It is situated seven miles west-south-west of Henbury cattle station on the dry Finke river, and about fifty miles south of the McDonnell Ranges in the very centre of Australia. Within an area of 500 yd. by 500 yd. thirteen craters were mapped. The largest is oval in outline, measuring 220 yd. by 120 yd. across, and with a depth of 50–60 ft. The other craters are roughly circular, with diameters ranging from 10 yd. to 80 yd. The walls consist of powdered rock and shattered blocks of Ordovician sandstone and slaty rock. Owing to the craters acting as collecting pans for rain-water in this arid region, the spots are prominently marked by the growth of mulga trees, acacias, and coarse grass. Scattered around the craters are numerous pieces of metallic iron, usually angular in shape, and ranging from a fraction of an ounce to 521/2 lb. in weight. In one area of 6 ft. by 6 ft. more than a hundred fragments were collected. Only two masses (one of 13 lb.) were found within the crater walls; and in one of the smaller craters a borehole to a depth of 8 ft. through fine silt down to coarse rock fragments yielded no mass of iron. Fragments of iron rust are also abundant; and some glassy material, suggesting fusion of the country rock, was found. These craters, which are very similar, were evidently formed by the impact of a shower of meteoric irons at some remote period.

On newly discovered meteoric irons from the Wallapai (Hualapai) Indian Reservation, Arizona

On newly discovered meteoric irons from the Wallapai (Hualapai) Indian Reservation, Arizona

The oxidation of meteoric irons with comparative descriptions of two new examples of magnetic iron oxides from terrestrial sources

The oxidation of meteoric irons with comparative descriptions of two new examples of magnetic iron oxides from terrestrial sources

Heretofore undescribed meteoric irons from [1] Bolivia, South America, [2] western Arkansas, and [3] Seneca Township, Michigan

Heretofore undescribed meteoric irons from [1] Bolivia, South America, [2] western Arkansas, and [3] Seneca Township, Michigan

Recently found meteoric irons from Mesa Verde Park, Colo., and Savannah, Tenn

Recently found meteoric irons from Mesa Verde Park, Colo., and Savannah, Tenn

On meteoric irons from Alpine, Brewster County, Texas, and Signal Mountain, Lower California, and a pallasite from Cold Bay, Alaska

On meteoric irons from Alpine, Brewster County, Texas, and Signal Mountain, Lower California, and a pallasite from Cold Bay, Alaska

The classification of Meteorites

The first broad grouping of meteorites was into irons and stones according as they consisted mainly of nickeliferous iron or of silicates. These were the two main divisions of the first really serviceable classification as applied by Gustav Rose in 1862-4 to the collection of meteorites in the, University Museum of Berlin. In this classification the division of meteoric irons included as separate groups the pallasites and the mesosiderites, in which nickel-iron "rod silicates are present in about equal amounts; and the meteo~fic stones were for the first time split up into chondrites, or stones containing those curious rounded grains (chondrules) peculiar to meteorites, and non-Chondritic stones, which were divided according to mineralogical composition into the groups of eucrites, howardites, &c., still largely recognized.

The Microscopy of Metals

AT the very successful symposium on the microscope organised by the Faraday Society on January 14 in the rooms of the Royal Society, about one-half of the papers presented dealt with the microscopical examination of metals, a striking indication of the importance which this branch of microscopy has now acquired. It was therefore appropriate that the president, himself a distinguished worker in this field, should deal historically with the development of micro-metallography, as well as contributing an original paper to the discussion. Sir Robert Hadfield's introductory address surveyed the history of microscopical in vention, and was illustrated by portraits of some of the pioneers in the art-Jansen, Lipperhey, Leeuwenhoek, Sorbyr and Dallinger. We were reminded of the fact that, so far back as 1665, Robert Hooke described, in his “Micrographia” the appearance of the point of a needle and the edge of a razor, and his faithful drawings of these two objects, revealing most accurately the features which could be observed under a low magnifica tion, are reproduced in the paper. The next in stance of the application of the microscope to the examination of metals is that by Réaumur, whose work on steel, published in 1722, contains many drawings of the magnified fractures of iron and steel bars. Such a method, however, gave little information, and did not lead to any further development. In 1808 Widmanstatten studied the structure of meteoric irons by polishing a plane section and heating until the constituents became differentially coloured by oxidation, thus introduc ing the method now familiar as “heat-tinting.” The structure of these irons is so coarse that mag nification is unnecessary, but the method gave hints to later workers, of whom Sorby is the chief. The work of Sorby, in view of its great importance, was dealt with by the president in a separate note.

A method for the quick determination of the approximate amount and composition of the nickeliferous iron in Meteorites ; and its application to seventeen meteoric stones

In the classification proposed by the author in a previous paper meteorites are divided into five groups according to the ratio of iron to nickel in the nickeliferous iron they contain. In the case of the meteoric irons such a classification, as shown by Farrington's list of analyses, is a natural one, since the structure of the irons, as revealed by etching, varies with the amount of nickel they contain. Thus Group 1, in which the metal is poor ill nickel, with a ratio of Fe to Ni of 13 upwards, includes nickel-poor ataxites, hexahedrites, and Coarsest and coarse octahedrites ; Group 2, in which Fe : Ni =8-13, the rest of the octahedrites from medium to finest ; Group 8, in which Fe : Ni = 5-8, nickel-rich ataxites; Group 4, in which Fe: Ni = 2-5, ataxites still richer in nickel; while Group 5 may include the doubtful Oktibbeha meteorite in which the ratio of iron to nickel is even less than one.

XI. On the photographic spectra of meteorites

For several years I have been engaged on the spectrum analysis of Meteorites. Many meteoric specimens have come into my possession—through the kindness of friends— especially am I indebted to the Trustees of the Natural History Museum and to Dr. Prior, who presented me with specimens of such of the meteorites of which the quantity in their possession would not be appreciably diminished by the loss of the two or three grms. required for my experiments. The Research is divided naturally into the examination of meteoric stones and meteoric irons. I propose at present to deal with meteoric stones or aerolites. These wonders of the sky consist generally of one or more silicates (mainly olivine and bronzite), interspersed with particles of nickeliferous iron, troilite, &c. Recent developments have led to many original devices and modification of details in the working spectrograph, thus furnishing information which may be of interest to those engaged on this branch of spectroscopic analysis.

Notes on the Whitfield County, Georgia, meteoric irons, with new analyses

Notes on the Whitfield County, Georgia, meteoric irons, with new analyses

The Meteor Crater of Canyon Diablo, Arizona; Its History, Origin, and Associated Meteoric Irons. George P. Merrill

Previous articleNext article FreeReviewsThe Meteor Crater of Canyon Diablo, Arizona; Its History, Origin, and Associated Meteoric Irons. George P. Merrill H. H.H. H. Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 16, Number 6Sep. - Oct., 1908 Article DOIhttps://doi.org/10.1086/621566 Views: 40Total views on this site PDF download Crossref reports no articles citing this article.

Our Astronomical Column

SPECTRUM ANALYSIS OF METEORITES.—A research of great interest has been undertaken by Messrs. W. N. Hartley and Hugh Ramage on the wide dissemination of the rarer elements and the mode of their association in the more common ores and minerals. The outcome of this work has led us to believe that the rarer metals are more widely distributed than was ever dreamt of, the authors showing that out of ninety-one iron ores obtained from the Dublin Royal College of Science, thirty-five contained the extremely rare metal gallium, while most of them contained constituents of an unusual character. Thus rubidium was commonly present: the magnetites invariably contained gallium, but no indium; the siderites all contained indium, but lacked gallium. In a more recent research they have investigated spectroscopically numerous meteoric ores, siderolites and meteorites (Scientific Proc. of the R. Dublin Soc, vol. viii. (N.S.) Part vi., No. 68), the range of spectrum being between the wave-lengths 6000 and 3200, and the results they obtained in this case, arranged in tabular form, are of great interest. It is shown that the composition of different meteoric irons is very similar, though the proportions of constituents differ somewhat. Meteoric irons, different varieties of iron ores, and manufactured irons contain copper, lead, and silver. Gallium is a constituent of meteoric irons, but not of all meteorites, and occurs in varying proportions. Sodium potassium and rubidium are constituents of meteoric irons, but only in very small proportions. Meteoric stones, but not the irons, contain chromium and manganese. Nickel was found to be a principal constituent in all meteorites, meteoric irons, and siderolites, cobalt occurring in the two last varieties. The authors describe the chief points of difference between telluric and meteoric iron to be the absence of nickel and cobalt in any considerable proportion from the former, and the presence of manganese. Meteoric irons, on the other hand, contain nickel and cobalt as notable constituents, and, except in minute traces, manganese is absent. In referring to the photographic spectra of iron meteorites obtained by Sir Norman Lockyer from the Nejed and Obernkirchen meteorites, the authors point out that of the two lines, one described as “unknown,” and the other as “doubtfully ascribed to iron,” the former is certainly, and the latter probably, a gallium line. At the conclusion of their paper the authors give three plates, which reproduce the flame spectra of six metallic irons and three siderolites with comparison spectra.

On two meteoric irons

On two meteoric irons

Scientific Serials

American Journal of Science, May.—Radiation of atmospheric air, by C. C. Hutchins. A stream of hot air was arranged so that it could be made to pass in front of one of the faces of a thermopile at a distance of 3 cm., and cause a deflection of a galvanometer needle, or the air could be discharged high above the thermopile, leaving it unaffected except by radiation from a large Leslie cube containing water at the temperature of the laboratory. There was no sort of agreement between measures made on eight different days to determine the absolute radiating power of a column of air 1 centimetre thick at a temperature near 100°C.; but in an ordinary room and under average conditions the value came out = 0.000001133+0.00000000711 (t-t′), where t-t′ is the difference in temperature between the air and the cube. Tyndall's result, that the radiation increases with the amount of moisture in the air, was confirmed, but no exact law of connection between the two was found. This is probably due to the presence of accidental impurities in the air employed. The increase of radiation proves to be proportional to the increase of temperature. There was a small increase of radiating power when sheets of air more than 1 centimetre thick were used; with sheets less than this thickness, no difference of radiation could be detected.—Atmospheric radiation of heat and its importance in meteorology, by Cleveland Abbe. In this interesting and exhaustive paper Prof. Abbe brings together practically all the conclusions that have been arrived at on atmospheric movements and their relation to radiation from the air. In his words, “A comprehensive study of fluid motions shows that air and water alike may be forced to ascend without being warmer and lighter, or to descend without being colder and denser, than the surrounding fluid. The currents and whirls behind any obstacle in streams of air or water are almost wholly independent of differences of density, and are caused by differences of pressure as modified by simple kinetic laws.“ These motions, which the air is forced to take for purely kinetic reasons, are specially discussed in detail, but it is impossible to enumerate, in an abstract, the many cases considered.—Experiments upon the constitution of certain micas and chlorites, by F. W. Clarke and E. A. Schneider. The minerals analyzed are waluewite, v. of xanthophyllite, clinochlore, leuchtenbergite, diallage, serpentine, and mica from Miask, Ural.—On the qualitative separation and detection of strontium and calcium by the action of amyl alcohol on the nitrates, by P. E. Browning.—The age and origin of the Lafayette formation, by Eugene W. Hilgard.—On the influence of swamp waters in the formation of the phosphate nodules of South Carolina, by Dr. Charles L. Reese. From the experiments it appears probable that both carbonic acid and the humus substances in fresh-water swamps play an important part both in the accumulation and the concentration of calcium phosphate, and thus in the formation of phosphate nodules, these being considered to be phosphatised marls.— Plattnerite, and its occurrence near Mullars, Idaho, by William S. Yeates; with crystallographic notes by Edward F. Ayres.— On the occurrence of Upper Silurian strata near Penobscot Bay, Maine, by William W. Dodge and Charles E. Beecher.—Zinc-bearing spring waters from Missouri, by W. F. Hillerbrand. The chief constituent salt in the spring in question is zinc sulphate. It forms about 56 per cent, of the total dissolved solids.—A meteorite from Central Pennsylvania, by Prof. W. G. Owens. A chemical analysis of the meteorite gave Fe 91˙36, Ni 7˙56, Co 0˙70, P 0˙09, S 0˙06, Si trace = 99˙77.—On two meteoric irons, by G. F. Kunz and E. Weinschenk. One of the masses examined came from Indian Valley Township, Floyd County, Virginia; the other from Sierra de la Ternera, Province of Atacama, Chili.—The molecular masses of dextrine and gum arabic as detrmined by their osmotic pressures, by C.E. Linebarger. The molecular masses of dextrine and gum arabic as determined by their osmotic pressures, by C. E. Line-barger. The molecular mass of gum arabic is found to be about 2500, of dextrine 1134, and of colloid tungstic acid 1750. In each of these three cases the colloid molecule is seven times the simple molecule.

Meteoric Iron

THE Annalen des k.k. naturh. Hofmuseums, No. 2 of vol vi., contains a further contribution by E. Cohen and E, Weinschenk to their interesting studies on meteoric irons.