Surface acoustic wave studies of hydrogen entry into a Ni-base alloy
Rayleigh acoustic waves were propagated along the surface of a sheet sample of a Ni alloy while the alloy was undergoing electrolytic charging with hydrogen. The waves were propagated, at frequencies from 2 to 15 MHz, from a transmitting to a receiving transducer, and their attenuation and velocity were monitored. A number of experiments was conducted to ensure that Rayleigh conditions were met and that extraneous results due to such effects as passive film changes and bubble formation were minimal. During cathodic polarization, wave velocity and attenuation decreased. The attenuation decrease followed two stages: an instantaneous one, probably due to polarization effects in the electrolyte, and a gradual one associated with the entry of hydrogen into the alloy. Both the instantaneous and gradual decreases were reversible and were recovered when polarization was removed. The kinetics of the recovery of the gradual component of attenuation were described by the Granato-Hikata-Luecke model for unpinning of dislocations by point defects. All results indicated that the surface wave technique was sensitive to hydrogen atom entry into the surface and that the entering atoms migrated to and pinned dislocations within a layer of thickness much less than the Rayleigh wavelength.
- Research Organization:
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
- OSTI ID:
- 6543963
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 52:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HYDROGEN
ABSORPTION
NICKEL ALLOYS
ACOUSTICS
SORPTIVE PROPERTIES
ATTENUATION
DATA
DISLOCATIONS
ELECTROLYSIS
KINETICS
MHZ RANGE
POINT DEFECTS
RAYLEIGH WAVES
SURFACES
TRANSDUCERS
VELOCITY
WAVE PROPAGATION
ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
FREQUENCY RANGE
INFORMATION
LINE DEFECTS
LYSIS
NONMETALS
SEISMIC SURFACE WAVES
SEISMIC WAVES
SURFACE PROPERTIES
360603* - Materials- Properties