ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04070.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe use of hollow cone illumination in improving the contrast transfer in bright field high resolution electron micrographs is investigated experimentally. Analysis of the results on an optical bench indicates that, although the contrast transfer is free of sign reversals, the contrast is reduced by a factor of up to 3ṁ3 in relation to axial bright field imaging. This constitutes a severe limitation to the usefulness of the hollow cone bright field technique, particularly in situations where the signal to noise level is already poor, as in high resolution imaging of non‐crystalline specimens. Factors governing the contrast in hollow cone illumination are discus

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04071.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThin films of amorphous carbon, silicon and germanium have been examined at high resolution at accelerating voltages up to 575 kV with the Cambridge University high resolution electron microscope. The directly interpretable resolution has been demonstrated to extend to 0ṁ22 nm, so that the microscope is capable of providing unambiguous structural information at the atomic level. The observations of both carbon and silicon were, however, somewhat disappointing in that no significant specimen detail was revealed despite the improved performance compared with that of conventional 100 kV instruments. Some of the factors involved in observation and interpretation of these images are discusse

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04072.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYResults are presented of a preliminary investigation of the structure of sputtered films of amorphous arsenic, using both high resolution bright field and tilted illumination dark field imaging modes. It is demonstrated that the material is not microcrystalline but appears to show a different form of short range order than is seen in films of amorphous carbon or germanium. The low angle scattering for the thin films was found to be very variable and it is suggested that this is associated with variability of a ‘cavern‐like’ structure and of the normal triple coordin

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04073.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYElectrodeposited amorphous Ni3P was deformedin situon a brass substrate. The films, when observed in the electron microscope, showed both light and dark bands in bright field images which were not seen in undeformed material. It is proposed that the origin of this contrast is a change of both density and structure of the material within the deformation bands.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04074.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYAmorphous Cu60Zr40alloy, prepared by a levitation melt and double roller quenching technique has been severely cold rolled. Preliminary observations show the presence of two kinds of defects with different morphologies. In both cases the defects have a contrast which corresponds to that for a lower projected atomic density at the defect.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04075.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe commercial binary metallic glass, Fe80B20, was examined using transmission electron microscopy after a variety of ageing treatments. While the material was found to be susceptible to beam‐induced oxidation, some tendency to crystallization at temperatures as low as 523 K was observed. Morphologically this was different from the essentially eutectic crystallization behaviour previously observed at 573 K and abov

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04076.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA number of amorphous and partially crystalline palladium‐silicon alloys have been examined by high resolution transmission electron microscopy at 500 kV. With the directly interpretable resolution extending beyond the first peak in the structure factor at 0ṁ23 nm, details of the local microstructure at the atomic level are visible. Images of small metallic particles show a well‐defined pattern of fringes over local regions. In some instances, especially in partially‐ordered alloys, neighbouring or overlapping fringe patterns appear to be orientationally‐related in a similar manner to fringe systems seen in symmetrically multiply‐twinned particles. The significance of this type of structural examination for amorphous metals i

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04077.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYTransmission electron microscopy at 100, 900 and 1000 kV was used to study the early stages of growth of internally nucleated crystals of the phase Na2O.2 CaO. 3 SiO2(‘NC2S3’) in glasses close to the NC2S3composition. Glass samples were partially crystallized by heat treatment in the range 833–873 K and thin foils for electron microscopy were prepared by ion beam thinning. The phase identified by electron diffraction from a number of small crystals (the low temperature form of NC2S3) was the same as that determined by X‐ray diffraction of fully crystallized glass ceramics. Selected area diffraction and bright and dark field microscopy showed that in the early stages of development the crystallization centres were essentially single crystals but contained a significant concentration of defects. These crystals were nucleated, probably homogeneously, at temperatures higher than the well‐established low to high reversible polymorphic transformation of the NC2S3crystalline phase. In a glass of similar composition to which platinum was deliberately added there was clear evidence for heterogeneous nucleation of NC2S3crystals on platinum particles distributed in the glass. Also the contact angle between NC2S3crystals and the rounded platinum particles could be measured

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04078.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYHigh resolution electron microscopy has been used to image intergranular glassy phases in sintered and hot‐pressed nitrogen ceramics, and the Si‐SiO2interfaces important in MOS devices.The thin intergranular glassy phases were found at most grain boundaries in all liquid‐phase sintered or hot‐pressed ceramics examined. Silicon carbide sintered by a solid state diffusion process, however, contained no such phases.Si‐SiO2interfaces have been examined in cross‐section at about 0ṁ3 nm resolution. The images show that the transition from the Si crystal to the amorphous oxide was abrupt, but that there were 0ṁ3‐0ṁ5 nm high hills on the Si surface, separated by 2–4 nm, and long‐range undulations of 0ṁ6‐0ṁ8 nm height and 20–50 nm periodicity. Ultra‐thin (3 nm) oxides were also examined and were found to be uniform in thinkness, indicating that the roughness at the Si‐SiO2interfaces is initially caused by irregularities on

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04079.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY