Showing papers on "Transmission electron microscopy published in 1969"
TL;DR: In this paper, the decomposition of vanadium pentoxide at temperatures up to 400°C in vacuum has been investigated using transmission electron microscopy and a number of new phases have been found.
52 citations
TL;DR: Skin microscopy revealed the local charring reaction and the development of smooth surfaces of erythema-edema in target areas induced by the laser impact, and the surface topography of the target and adjacent areas of living skin was studied.
50 citations
TL;DR: In this paper, the Ni-12 at. % Ti alloy was studied by means of thin foil transmission electron microscopy and electron diffraction technique, which showed two stage age-hardening at 500°C and 600°C.
Abstract: Precipitation behaviour in Ni-12 at. % Ti alloy was studied by means of thin foil transmission electron microscopy and electron diffraction technique. Hardness measurements showed two stage age-hardening at 500°C and 600°C. Thin foil observations revealed that the initial rapid increase in hardness was associated with the presence of superlattice. Slower second hardening was caused by the formation of modulated structure or periodic ordered structure. The increase in hardness by these periodic structures was found to be due to the internal strain hardening as originally suggested by Mott and Nabarro.
37 citations
TL;DR: In this paper, anodic barrier layer oxide was observed with a boric acid electrolyte maintained at 60°C and two film layers were observed: the uppermost layer being extremely thin and the secondary phase barrier layer being on the order of 200Aa.
Abstract: Direct observations of anodic barrier layer oxide, by transmission electron microscopy, provide further evidence for the duplex film structuring suggested earlier, based on infrared data. Anodic films were prepared with a boric acid electrolyte maintained at 60°C and two film layers were observed: the uppermost layer being extremely thin. Only the layer lying next to the metal (primary phase barrier layer) showed a thickness relationship with respect to forming voltage: 14.8 Aa/v. The thickness of the uppermost layer (secondary phase barrier layer) was on the order of 200Aa and was essentially independent of forming voltage. With the boric acid electrolyte employed at 90° C, a pronounced increase was found in the thickness of the uppermost layer. The thickness of the layer next to the metal surface remained consistent with the ~14 Aa/v relationship. Infrared, coating weight, effluent gas detection, and impedance data were also obtained for these coatings and correlated with the data obtained by transmission electron microscopy.
32 citations
TL;DR: In this article, a modified form of jet etching using a turbulent jet enables large areas suitable for transmission electron microscopy to be easily produced from all types of specimens, both annealed and unannealed.
Abstract: Silicon has been implanted with between 1014 and 1016 boron ions/cm2 at energies of 25, 50, 75 and 100 keV; it has also been annealed at temperatures of between 873 and 1073 °K when the implanted boron ions occupy substitutional sites and form a ‘doped’ surface layer in which the doping profile can be accurately controlled, a desirable property in the manufacture of solid state circuits and devices (Large & Bicknell 1967). The implanted layers have been examined by both electron microscopy and electron diffraction before, during and after annealing to study the changes in crystal structures involved. For transmission electron microscope studies the silicon must be thinned to provide areas less than 1 p m in thickness, otherwise the electron beam is entirely absorbed within the specimen. It has been found that a modified form of jet etching using a turbulent jet enables large areas suitable for transmission electron microscopy to be easily produced from all types of specimens, both annealed and unannealed. Although specimens have been prepared and implanted with boron ions of different energies and doses the results discussed, which are typical of the range covered, are those obtained from silicon implanted with single energy 50 keV boron ions with a dose of 2 x 1015 ions/cm2.
29 citations
Abstract: The electron diffraction patterns of sphalerite structure ZnTe films evaporated in vacuum onto NaCl, BaF2 and CaF2 substrates contained numerous satellite spots. The diffraction patterns from (100) ZnTe films grown on cleavage faces of NaCl always contained satellite spots that arose from grains of wurtzite structure material with the (0001) plane parallel to the plane of the film and doubly positioned by a 30‡ rotation about the normal to the film. Other satellite spots occurred due to the presence of cubic microtwins and other types of included grains of wurtzite. Films grown under cleaner conditions had simpler structures.
24 citations
TL;DR: In this article, the authors studied the oriented overgrowth of titanium films obtained by evaporation in an ultrahigh-vacuum system onto mica using reflection electron diffraction and transmission electron microscopy and diffraction.
Abstract: The oriented overgrowth of titanium films obtained by evaporation in an ultrahigh‐vacuum system onto mica was studied in situ by reflection electron diffraction and, after withdrawal from the system, by transmission electron microscopy and diffraction Films with a thickness of 100 A or more, prepared on a mica at temperatures of 500°–600°C, are epitaxial single crystals of hexagonal structure; their basal plane is parallel to that of the substrate and the crystallographic axes within the contact planes form an average angle of 30° These single‐crystal films have a smooth surface and are composed of subgrains rotated around the c axis with respect to each other, forming angles up to 4° Films thinner than 100 A are only partially oriented Coalescence in these films takes place at a very early stage of growth and continuous films of about 100 A are obtained, in contrast with the growth of other metals on mica
18 citations
TL;DR: In this article, the authors examined the relationship between silver and its sulphide by transmission electron microscopy and selected area electron diffraction method, and they showed that a surface diffusion of silver is very fast even at room temperature and a factor controlling the growth of sulphide crystals.
Abstract: Sulphuration process of vacuum-deposited silver films and orientation relationship between silver and its sulphide were examined by transmission electron microscopy and selected area electron diffraction method. Acanthite (β-Ag2S) crystals grew with a relation of (012)Ag2S//(001)Ag and Ag2S// Ag on the (001) single-crystal surface of silver, and with a relation of (012)Ag2S//(111)Ag and Ag2S// Ag on the (111) surface. The sulphide crystals were nucleated at random over the silver surface and the dislocations in silver did not seem to play any special role in the nucleation of sulphide. The crystals which appeared at stacking faults or twins were larger than those formed at the other sites. The films were often broken-down and transparent regions were observed. The sulphide crystals became such thick crystals as did not transmit the 100 kV electron beam. The results seem to show that a surface diffusion of silver is very fast even at room temperature and a factor controlling the growth of sulphide crystals.
14 citations
TL;DR: In this paper, thin cermet films of gold/silicon monoxide were deposited at 100° and 240°C on to glass substrates previously coated with 100-A-thick carbon films.
Abstract: Thin cermet films of gold/silicon monoxide were deposited at 100° and 240° C on to glass substrates previously coated with 100-A-thick carbon films. Cermets ranging from 47%–86% by weight of gold were studied by electron- and x-ray diffraction and by transmission electron microscopy so as to correlate their structures and electrical properties. Electrical resistivities observed lay between 10−2 and 10+3 Ω-cm at room temperature. These values were independent of film thickness, of the magnitudes of applied electric and magnetic fields up to 100 V/ cm and 9000 G, respectively, of frequency up to 20 kHz, and of optical illumination. The Hall mobilities of the carriers were less than 0.3 cm2V−1sec−1. The current noise power varied inversely with frequency. All specimens bad a negative temperature coefficient of resistance whose magnitude was a strong function of both composition and temperature, but at a given composition it reached a constant value at a temperature below about 70K. The cermet structures con...
14 citations
TL;DR: It is concluded that when fluid from the tissues lines the pores and becomes stained the filter structure is visible and those filters placed either on the endoderm or between the ectoderm and Endoderm of the chick embryo show clearly defined pores.
13 citations
TL;DR: In this article, a method of thinning tellurium single crystals by chemical polishing has been developed for the study of dislocations by transmission electron microscopy and the preliminary results concerning the identification of the glide planes and the Burgers vectors of dislaps in this material are described together with some comments on the contrast phenomena resulting from the high elastic anisotropy of telluria.
Abstract: A method of thinning tellurium single crystals by chemical polishing has been developed for the study of dislocations by transmission electron microscopy. The preliminary results concerning the identification of the glide planes and the Burgers vectors of dislocations in this material are described together with some comments on the contrast phenomena resulting from the high elastic anisotropy of tellurium.
TL;DR: Ferroelectric domain boundaries in "Remeika" single crystals of tetragonal barium titanate were observed by transmission electron microscopy in this paper, where both 180 and 90° walls were observed and described with regard to appearance and motion.
Abstract: Ferroelectric domain boundaries in "Remeika" single crystals of tetragonal barium titanate were observed by transmission electron microscopy. Both 180 and 90° walls were observed and are described with regard to appearance and motion. The 90° boundaries are discussed in greater detail with respect to their interactions and nucleation.
TL;DR: In this article, single crystals of germanium irradiated with fast neutrons have been studied by means of transmission electron microscopy, and the contrast of the defects was found to depend on the diffraction conditions and suggests that the defects are associated with a strain field.
Abstract: Single crystals of germanium irradiated with fast neutrons have been studied by means of transmission electron microscopy. Observation of the irradiated specimens reveals defects which have a size distribution with a tail extending to larger sizes and a most probable diameter of 38 A. The contrast of the defects was found to depend on the diffraction conditions and suggests that the defects are associated with a strain field.
TL;DR: In this paper, various factors influencing the epitaxial temperature are studied by transmission electron microscopy in the initial stages of growth and it is concluded that the number of nucleation sites depends on the experimental conditions.
Abstract: Various factors influencing the epitaxial temperature are studied by transmission electron microscopy in the initial stages of growth. The particle density at a constant mean thickness is nearly independent of the deposition rate. The electric field applied to the substrate surface brings about the lowering of the epitaxial temperature. The effect is more pronounced by an addition of electron irradiation to the substrate. In accordance with the lowering of the epitaxial temperature, the particle density is increased by the electric field and electron irradiation. From these results, it is concluded that the number of nucleation sites depends on the experimental conditions and that the expitaxial temperature is lower if more sites are present. The results are discussed in terms of Walton’s theory.
TL;DR: In this paper, the results of examination of 12 metal and alloy powders by the scanning electron microscopy (SEM) and optical microscope are presented and compared, and the principle of operation of SEM is briefly discussed.
TL;DR: In this paper, the initial stages of oxide formation on thin foils of copper, Cu-2.5Si, and Cu-7.5Al-2Si alloys were studied by transmission electron microscopy and electron diffraction over the temperature range 200-380 C (392-716 F).
Abstract: The initial stages of oxide formation on thin foils of copper, Cu-2.5Al-2.5Si, and Cu-7.5Al-2Si alloys in moist atmospheres of oxygen and sulfur dioxide have been studied by transmission electron microscopy and electron diffraction over the temperature range 200-380 C (392-716 F). On the Cu-2.5Al-2.5Si alloy grain boundaries and twin boundaries are preferential sites for oxide nucleation. On the Cu-7.5Al-2Si alloy no preferential sites are observed. The relative reactivities of different crystallographic planes are the same for the alloys as for the metal. On oxidized thin foils a prenucleation thermal pitting phenomenon has been observed at temperatures very much lower than the thermal pitting observed by other workers. Oxide nuclei have been observed to form on a thin amorphous layer of oxide even when there is no metal directly underneath. These results are discussed with reference to current theories on the initial stages of oxide formation. It is concluded that in the prenucleation stage the...
TL;DR: Thin foil preparation technique for transmission electron microscopy and selected etch pitting technique for CoO single crystals for single crystals is described in this paper, where the authors present a method for selecting etch-pitting for single crystal.
Abstract: Thin foil preparation technique for transmission electron microscopy and selected etch pitting technique for CoO single crystals
TL;DR: The recent correlation between the Burgers vectors (b) of dislocations in deformed α-iron as deduced from field-ion microscopy and transmission electron microscopy is re-examined in this paper.
Abstract: The recent correlation between the Burgers vectors (b) of dislocations in deformed α-iron as deduced from field-ion microscopy and transmission electron microscopy is re-examined. It is concluded that there is no evidence for the existence of dislocations of b = a〈110〉 from transmission electron microscopy and that there is some doubt as to the precise meaning of the field-ion observations.
01 Dec 1969
TL;DR: Two stage electropolishing technique for preparation of multiphase alloys for transmission electron microscopy was used in this article, where the alloys were prepared using two stages.
Abstract: Two stage electropolishing technique for preparation of multiphase alloys for transmission electron microscopy
TL;DR: In this paper, Li foils for transmission electron microscopy were prepared by shaving a Li bar in a dry box under an Ar atmosphere, and the specimen was transferred to the microscope using a modified Hitachi specimen exchange device.
Abstract: Li foils for transmission electron microscopy were prepared by shaving a Li bar in a dry box under an Ar atmosphere. The specimen was transferred to the microscope using a modified Hitachi specimen exchange device. Li single‐crystal diffraction patterns were observed. The microstructure consisted of small grains containing rapidly moving dislocations.
01 Jan 1969
TL;DR: In this article, the growth rate of thin silicon films by the electron beam dissociation of adsorbed tetramethylsilane has been investigated, and the authors found that there is a region where the value of growth rate can be calculated from the expression r=KPJ expa/T, where K and a are constants.
Abstract: The deposition of thin silicon films by the electron beam dissociation of adsorbed tetramethylsilane has been investigated. Growth rate was studied as a function of P the vapor pressure of tetramethylsilane, T the substrate temperature, and J the current density. It was found that there is a region where the value of the growth rate can be calculated from the expression r=KPJ expa/T, where K and a are constants. Assuming a model in which a=Q/R and K=cσ, where R is the gas constant and c is a calculable constant, Q, the heat of adsorption, was found to be 11.6 kcal/mole and σ, the collision cross section, was determined to have the unexpectedly high value of 3.86×103 A2 for 300‐V electrons. Electron diffraction and transmission electron microscopy showed the as‐deposited films to be amorphous. The resistivity of these films varied with thickness and showed a minimum value of approximately 5×104Ω·cm when the film thickness was between 1000 and 1500 A. Thinner films were less conductive because the high amou...
TL;DR: In this article, a solution machining method was used to produce specimens with a thickness in the order of 1000 A or less, which was operated at low beam intensity to minimize radiation damage to the specimens.
Abstract: : The paper describes the transmission electron microscopy of sodium chloride. A solution machining method was used to produce specimens with a thickness in the order of 1000 A or less. The electron microscope was operated at low beam intensity to minimize radiation damage to the specimens. Typical structures are compared with other results in the electron microscopy of alkali halides. Some of the dislocation structures in sodium chloride are similar to those in magnesium oxide. (Author)
TL;DR: In this paper, the preparation of clean thin foils of beta titanium suitable for transmission electron microscopy is discussed, and special attention is given to material containing omega precipitation, which is a special case of material containing alpha precipitation.
Abstract: The preparation of clean thin foils of beta titanium suitable for transmission electron microscopy is discussed. Special attention is given to material containing omega precipitation.
01 Jan 1969
TL;DR: In this article, the results of a study to determine methods of producing foilis of U T-1/2% Nb 21 2% Zr alloy to be used for trammisetion electron microscopy were presented.
Abstract: Thifa report presents the results of a study to determine methods of producing foilis of U T-1/2% Nb 21/2% Zr alloy to be used for trammisetion electron microscopy. Suitable foils were produced by spark cutting and spark planing followed by final thinuing in 8 d u d jet thinner using; a solution of 6% HClO4 in methanol. A chemical etch-polishing solution consisting 04 55 ml HC1, 25 ml H20, 5 ml HNOQ and 1 ml(25 drops) HF has also been developed for intermediate thinuing to replace spark planing for faster preparation of I gamma phaBe material.