Particulate Metal Composites as Backing for Ultrasonic Transducers for Continuous Nondestructive Measurements at Moderate and High Temperatures

The principles of operation and design of immersion ultrasonic transducers developed by the authors for excitation and reception of elastic vibrations in moving filament-like and plane-parallel materials, in particular, polymer fibbers and films, with an adjustable angle of input (reception) of probing signals into moving controlled object – polymer fibbers and films at normal and high temperatures. The technical characteristics of the installation are given in which the converters developed by us are used, namely, sounding base (distance from the emitter to the receivers), the duration of the probing pulses, the frequency of filling and the duration of the probing pulses, the speed of the controlled object, the combined standard measurement uncertainties of the difference Δt of the propagation times of ultrasonic waves from the emitter to the first and second signal receivers, relative combined standard uncertainties of measurements of attenuation coefficient and velocity of propagation of ultrasonic waves.

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Inclusion-Size-Independent Strength of Glass/Particulate-Metal Composites

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.1988.tb05080.x ◽

1988 ◽

Vol 71 (5) ◽

pp. C-276-C-279 ◽

Cited By ~ 9

Author(s):

Thomas B. Troczynski ◽

Patrick S. Nicholson ◽

Carmen E. Rucker

Keyword(s):

Inclusion Size ◽

Metal Composites ◽

Particulate Metal

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In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087616 ◽

1991 ◽

Vol 49 ◽

pp. 660-661

Author(s):

Z. L. Wang ◽

J. Bentley

Keyword(s):

High Temperatures ◽

Image Resolution ◽

Atomic Processes ◽

Crystal Surfaces ◽

Beam Radiation ◽

Surface Areas ◽

Transmission Electron ◽

Reflection Electron Microscopy ◽

Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

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