High frequency ultrasonic characterization of sintered SiC
High frequency (60 to 160 MHz) ultrasonic nondestructive evaluation was used to characterize variations in density and microstructural constituents of sintered SiC bars. Ultrasonic characterization methods included longitudinal velocity, reflection coefficient, and precise attenuation measurements. The SiC bars were tailored to provide bulk densities ranging from 90 to 98 percent of theoretical, average grain sizes ranging from 3.0 to 12.0 microns, and average pore sizes ranging from 1.5 to 4.0 microns. Velocity correlated with specimen bulk density irrespective of specimen average grain size, average pore size, and average pore orientation. Attenuation coefficient was found to be sensitive to both density and average pore size variations, but was not affected by large differences in average grain size.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- OSTI ID:
- 5677453
- Report Number(s):
- N-88-23985; NASA-TM--100825; E--4013; NAS--1.15:100825; CONF-870172--
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ACOUSTIC TESTING
ATTENUATION
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
DENSITY
FABRICATION
GRAIN SIZE
MATERIALS TESTING
MICROSTRUCTURE
NONDESTRUCTIVE TESTING
PHYSICAL PROPERTIES
POROSITY
SILICON CARBIDES
SILICON COMPOUNDS
SINTERING
SIZE
TESTING
ULTRASONIC TESTING