Showing papers on "Transmission electron microscopy published in 1968"
TL;DR: In this paper, a transmission electron microscopy investigation was made of the structural defects in nickel oxide films formed at 500° and 600°C on metallographically polished polycrystalline nickel.
89 citations
TL;DR: The microstructure of diamonds formed from the graphite in cast iron by an explosive shock process was investigated by means of transmission electron microscopy electron, diffraction, and selected beam microscopy.
Abstract: The microstructure of diamonds formed from the graphite in cast iron by an explosive shock process was investigated by means of transmission electron microscopy electron, diffraction, and selected beam microscopy. Morphologically, the material consists of a mixture of two different forms: compact aggregates of of usually acicular crystallites with a strong preferred orientation, and single crystals. The latter partly consist of hexagonal diamond, the recently discovered modification of carbon, and contain many stacking faults. Hexagonal diamond is also randomly distributed in the polycrystalline fraction.
65 citations
TL;DR: In this article, a high resolution technique was developed for the study of segregation and associated phenomena; a microanalysis is, in effect, performed on a highly magnified image of a specimen when examined by transmission electron microscopy.
Abstract: A new high resolution technique has been developed for the study of segregation and associated phenomena; a microanalysis is, in effect, performed on a highly magnified image of a specimen when examined by transmission electron microscopy. The method depends on the facts that electrons lose energy on transmission through the specimen, that the energy losses are characteristic of the material of the specimen, and that these energy loss electrons contribute to a normal image in the electron microscope. The spatial resolution of the technique is estimated to be about 10 nm. In the special case presented here, the measurements are semi-quantitative and concentration changes of about 1 wt. % are detectable. The technique is applied to the study of precipitation and associated segregation of magnesium at high angle grain boundaries in an aluminium 7 wt. % magnesium alloy after it has been quenched from different solution treatment temperatures. The results of the investigation are consistent with precipitate nucleation at the boundaries during the quench at a quench rate of 3 x 10$^{-4} ^\circ$C s$^{-1}$. Non-equilibrium segregation of magnesium to the boundaries is also indicated, and a model based on the converse of the Kirkendall effect is proposed to explain this.
64 citations
TL;DR: In this article, an interpretation of the Zr/ZrO 2 epitaxy on a zirconium (0001) plane is given, based on electron microscopy.
44 citations
TL;DR: In this article, the effects of cathode current density and film thickness on the film structure, crystal structure, composition, resistivity, currentvoltage characteristics, and optical energy gap were investigated.
Abstract: Highly nitrided films of tantalum have been prepared by cathodically sputtering high‐purity tantalum in a pure nitrogen atmosphere. The effects of cathode current density and film thickness on the film structure, crystal structure, composition, resistivity, current‐voltage characteristics, and optical energy gap were investigated. Transmission electron microscopy showed the films to be apparently discontinuous throughout the range of cathode current densities investigated for 1600 A thick specimens. The crystal structure determined by electron diffraction analysis was found to be body‐centered tetragonal with c=5.01 A, a=5.77 A, and c/a=0.87. The presence of small amounts of hexagonal TaN was also observed. Analysis of the gas content showed the amount of nitrogen to be a function of cathode current density and thickness. Electrical resistivity as a function of temperature in the range of 213°–373°K obeyed the relationship ρ=A exp(ΔE/kT), where ΔE decreased with the increasing cathode current density and ...
43 citations
TL;DR: In this article, the authors studied the properties of the images formed by diffraction contrast in thin silicon foils by extending the solutions of the basic equations of the dynamical theory of diffusion contrast with anomalous absorption to defects of the small size encountered in the research.
Abstract: Dislocation‐free single crystals of three types of silicon have been irradiated by 6×1017 and 5×1019 nvt of fast neutrons and studied by bright‐ and dark‐field transmission electron microscopy. Mean defect image size has been found to depend on the impurity content of the silicon and annealing treatment, ranging from 22 A in the most nearly pure silicon in the as‐irradiated state to a maximum of 40 A in the n‐type silicon after a 30‐min anneal at 700°C. Defect density ranges from 1017 images/cm3 in the as‐irradiated state to less than 1015 after a 1000°C anneal for 30 min. The density is not noticeably affected by the type of impurity, but is approximately proportional to neutron dosage. The properties of the images formed by diffraction contrast in thin silicon foils have been studied by extending the solutions of the basic equations of the dynamical theory of diffraction contrast with anomalous absorption to defects of the small size encountered in the research. An anomalously wide black‐white image is predicted in dark field from which it is possible to determine whether a defect has interstitial or vacancy character. A ratio in the order of 2 to 1 interstitial type to vacancy type was found in the n‐type silicon; the ratio in the other two types of silicon appeared to be more nearly unity.
42 citations
TL;DR: In this article, the formation of a sputtering structure after bombardment at normal incidence with Xe+, Cu+, or Pb+ ions of 50 to 80 keV energy has been revealed.
Abstract: Transmission electron microscopy of thin, polycrystalline copper foils has revealed the formation of a sputtering structure after bombardment at normal incidence with Xe+, Cu+, or Pb+ ions of 50 to 80 keV energy. In general, the surface of each individual grain degenerates into a “hill and valley” structure, so as to develop those {100} faces lying nearest to the plane of the surface. The sputtering structure has been found to be independent of any prior electropolishing surface structure. Similarity between the spacing and crystallographic direction of the sputtering structure, and the general appearance of the dislocation arrays produced by ion bombardment, suggests that these dislocations could influence the initiation of the structure. A tentative model based on this hypothesis is proposed to account for the periodicity of the observed sputtering effect.
36 citations
TL;DR: The method reduces the hazards of modifications caused by the repeated exposure of biological materials to the effect of low pressure, during the usual evaporation of a thin metal layer and subsequently in the scanning electron microscope.
Abstract: It is well known that electrically nonconducting specimens can be examined in a scanning electron micro-scope with a reasonable degree of success, either by prior evaporation of a thin metal film or decrease of the accelerating potential of the incident electron beam, whenever the concomitant decrease in resolution is acceptable. Considerable simplification in the preparation of polymer specimens has been achieved by spraying them with an antistatic aerosol, used in the textile industry, so that cellulose, protein (but not mammalian keratin), polyacrylonitrile, polyamide, polyester, polyethylene, polypropylene and polytetrafluoroethylene materials can be examined at the highest potential available in the Cambridge Stereoscan, namely 20 kv. In particular, our method reduces the hazards of modifications caused by the repeated exposure of biological materials to the effect of low pressure, during the usual evaporation of a thin metal layer and subsequently in the scanning electron microscope. It was successfully applied to the examination of small organisms, after drying and/or fixing according to the standard specimen preparation methods accepted in orthodox transmission electron microscopy.
27 citations
TL;DR: In this paper, the effects on the luminescence of both stacking faults and twin boundaries have been observed by comparing micrographs taken of the same crystals in a transmission electron microscope and in a scanning microscope.
Abstract: Cathodoluminescence in hexagonal and cubic zinc selenide single crystals at liquid nitrogen temperature has been investigated using a scanning electron microscope. The effects on the luminescence of both stacking faults and twin boundaries have been observed by comparing micrographs taken of the same crystals in a transmission electron microscope and in a scanning microscope. With the latter operating at magnifications up to 40 000 x, luminescence spectra have been observed from very small regions of thicker single crystals. On increasing the current density, a threshold effect was noted in the emission of certain peaks from thin basal plane intergrowths in the hexagonal platelets used. These peaks were identified as arising from cubic regions in the latter by comparison with the cathodoluminescence spectra of cubic crystals observed under similar conditions.
19 citations
TL;DR: In this article, a brief survey of the crystallite structure of magnetic electroless cobalt films deposited from an alkaline hypophosphite bath on to glass substrates has been undertaken.
Abstract: A brief survey, using transmission electron microscopy, of the crystallite structure of magnetic electroless cobalt films deposited from an alkaline hypophosphite bath on to glass substrates has been undertaken. With increasing pH values from 7.4 to 8.5, the overall continuity of the films improved for a given thickness, although the crystallites themselves became individually isolated. This isolation is responsible for the increase in coercivity observed over the same pH range. Micrographs of various specimens are included to illustrate the features discussed.
18 citations
TL;DR: In this article, a method of preparing thin glass films suitable for transmission electron microscopy is described, and preliminary results are discussed of the application of the technique to the study of phase separation in a Li2O-SiO2-P2O5 glass.
Abstract: A method of preparing thin glass films suitable for transmission electron microscopy is described Some preliminary results are discussed of the application of the technique to the study of phase separation in a Li2O–SiO2–P2O5 glass
TL;DR: In this article, the general cyclic deformation characteristics have been ascertained and some qualitative ideas on the mechanisms of deformation developed, and the width and spacing of the channels have been shown to be a function of the number of cycles.
Abstract: Copper single crystals irradiated to a neutron dose of 1·1 × 1018 n/cm2 (> 1 MeV) have been cycled between constant plastic elongation limits at room temperature. The general cyclic deformation characteristics have been ascertained and some qualitative ideas on the mechanisms of deformation developed. Transmission electron microscopy reveals that channels completely free of irradiation-produced defects are created during the cyclic strain programme. The width and spacing of the channels have been shown to be a function of the number of cycles. An electron microscope shadowgraph technique has also been used to study the exact shape and distribution of surface slip steps and the results are compared to the channel observations.
TL;DR: The structure of quenched and aged zone-refined gold and gold doped with 0·087, 0·17 and 0·35 at. % Zn has been studied by transmission electron microscopy as mentioned in this paper.
Abstract: The structure of quenched and aged zone-refined gold and gold doped with 0·087, 0·17 and 0·35 at. % Cd, and 0·15 at. % Zn has been studied by transmission electron microscopy. Thin foils of the mat...
TL;DR: In this article, a transmission electron microscopy study has been made of defects in yttrium aluminum garnet (YAG) and three kinds of planar defect were observed: antiphase boundaries generated by slip on {110} planes, antiphases domain boundaries separating regions of crystal which appear to have slightly different lattice parameter, and orientation twins.
Abstract: A transmission electron microscopy study has been made of defects in yttrium aluminum garnet (YAG). Three kinds of planar defect were observed: antiphase boundaries generated by slip on {110} planes, antiphase domain boundaries separating regions of crystal which appear to have slightly different lattice parameter, and orientation twins.
TL;DR: The most attractive advantages of the scanning electron microscopy are (a) direct examination, (b) no sample preparation, (c) accommodation of large size samples, (d) satisfactory resolution, range of magnification from 20X to 100,000X, very large depth of focus, and (e) capability to examine a specimen in a number of orientations as mentioned in this paper.
Abstract: Based on the above considerations, the scanning electron microscope has unique capabilities for the study of fracture surfaces and should extensively replace the replication fractography currently used with the TEM. The most attractive advantages of the SEM are (a) direct examination, (b) no sample preparation, (c) accommodation of large size samples, (d) satisfactory resolution, (e) range of magnification from 20X to 100,000X, (f) very large depth of focus, and (g) capability to examine a specimen in a number of orientations. Despite the absence of diffraction in the SEM (which appears to be the only disadvantage of this process, at present), it is obvious that, for fractography purposes, scanning electron microscopy has an equally important or a greater role to play than TEM fractography in the coming years.
TL;DR: In this article, a detailed study of heat-treated and deformed pyrolytic graphite has been made using transmission electron microscopy, where single-crystal characteristics are observed in material annealed at 3600° C.
Abstract: A detailed study of heat-treated and deformed pyrolytic graphite has been made using transmission electron microscopy. Single-crystal characteristics are observed in material annealed at 3600° C. Tilt boundaries are shown to be kinks in the basal planes with some twin boundaries which can be described in terms of dislocations, as for natural crystals.
TL;DR: Using transmission electron microscopy three types of precipitates have been observed in single crystals of uranium sulphide grown from the melt in this article, two of these have been identified as uranium oxysulphide and β-uranium disulphides and orientation relationships between them and the matrix have been determined.
TL;DR: In this paper, the slip behavior of uranium sulphide single crystals has been studied by transmission electron microscopy and it is shown that the primary slip plane is {110}, but that slip on {111} planes is also possible.
01 Sep 1968
TL;DR: In this article, a device was described for the electrolytic grinding of metal slices from a thickness of 1-2 mm to about 2 mm, as part of the preparation of thin metal foils for transmission electron microscopy.
Abstract: A device is described for the electrolytic grinding of metal slices from a thickness of 1-2 mm to about 02 mm, as part of the preparation of thin metal foils for transmission electron microscopy from bulk material.