Electron channeling contrast and electron backscattering patterns (EBSPs), generated in scanning electron microscopes (SEMs), were used to study the question of whether tent-shaped surface reliefs associated with ferrite plates in Fe-0.07 pct and Fe-0.50 pct C low-alloy steels are single crystals or back-to-back pairs of plates. Although more than 50 ferrite plates were examined in detail, any misorientation contained within them must have been <1 deg. Additionally, no sightings of the low-angle grain boundaries approximately bisecting ferrite plates expected on the back-to-back plates mechanism were ever made. The efforts of previous investigators to explain tent-shaped (and invariant plane-strain) reliefs on the basis of diffusional ledgewise growth were further extended.

Formation of invariant plane-strain and tent-shaped surface reliefs by the diffusional ledge mechanism

A method is described for converting video signals of analog scanning electron microscopes (SEMs) into digital images of high quality. A plug-in card commercially available for personal computers is used for the on-line analog/digital conversion. A Windows application program written by the authors, together with low-level software drivers supplied with the plug-in card, allow digital images to be recorded, to be displayed simultaneously on the computer monitor and to be saved as a file in a standardized format. Compared to conventional photographic images obtained from the SEM camera system, the digital images possess superior sharpness of outline, excellent image definition, diminished noise and well-defined grey-scale tones. This method provides SEM images of high quality for less than $1000 from most older analog SEMs. In addition, the advantages of digital image processing can be applied to analog SEMs, including contrast enhancement, digital filtering and multichannel recording.

A simple method for the acquisition of high-quality digital images from analog scanning electron microscopes.

Estimations of degree of hydration of portland cement pastes

Current flow in YBa2Cu3O7/PrBa2Cu3O7 multilayer structures has been studied using low temperature, scanning electron microscope, beam‐induced voltage contrast. Specialized data acquisition has been used to limit thermalization effects and improve resolution. For both via hole contacts and crossovers, the lowest critical current densities were found at steps where the superconductor tracks climb up or down over patterned edges of the insulator.

Spatially resolved critical current limitations in YBa2Cu3O7 multilayer structures

Significant progresses have been made in the past decades in the discipline of materials science, which include, but not limit to, the synthesis of new materials, advancement in analytical and experimental techniques, sustainable and environmentally friendly processing technologies, computational material science and nanotechnology. These developments have major influences on the research and application of heat treatment and surface engineering, and provide new opportunities to engineer the surfaces of new and conventional materials using advanced technologies to meet the ever increasing demands in surface and subsurface related properties. This survey gives a brief review on some aspects of heat treatment and surface engineering which keep pace with new developments in materials science. The specific areas being examined include: (i) advanced analytical techniques; (ii) sustainable and environmentally friendly technologies; (iii) surface engineering of emerging new materials such as intermetalli...

IFHTSE Global 21: heat treatment and surface engineering in the twenty-first century: Part 9 – Influence of materials science on heat treatment and surface engineering.

The programming and use of a purposebuilt digital image store constructed for a SEM is described. The system is based on purpose designed circuitry controlled by a Motorola MC68000 and is capable of noise-averaging using multiple frames, colour look-up tables, high-resolution photographic recording, image processing using matrix functions, some image quantification, and x-ray spectrum acquisition. The way in which the FORTH language provided an efficient means of controlling the SEM is described and examples of each type of operation are presented.

The application and programming of an image store for the SEM

Beam-induced voltage contrast has been demonstrated in a superconducting thin film of YBa2Cu3O7-x (YBCO) grown on MgO. Copper-rich inclusions in the material contribute to spatially varying resistive behaviour but do not account for all the observed details. A new method of scanning in which the beam was moved away from the sample between each data acquisition point was found to increase the resolution by limiting thermalisation, to allow imaging of resistive features as small as 0.5 μm. Direct comparisons of beam-induced contrast and micro-structure at 9000 times magnification were possible using simultaneous image acquisition via a purpose-built image store. Mounting a preamplifier within the scanning electron microscope chamber, to give a variable overall gain of 1000–100,000, was also found to significantly improve the signal-to-noise ratio.

J. K. Hulbert

Papers

The application and programming of an image store for the SEM

Low‐temperature SEM studies of beam‐induced voltage contrast in YBCO thin films