NMR (Nuclear Magnetic Resonance) studies of aging effects in palladium tritide
This paper presents Nuclear Magnetic Resonance (NMR) studies of aging phenomena in palladium tritide. /sup 3/He NMR relaxation parameters have been measured as a function of temperature for 6-, 13-, and 22-month-old beta phase palladium tritide. The most significant result of this study is the observation of a solid/fluid phase transition near 250/degree/K of /sup 3/He that has accumulated in the PdT/sub x/ substrate via triton decay. Although the existence of solid helium at relatively high temperatures had been predicted for helium in metals, it had not previously been confirmed in any metal/helium system. The observed melting temperatures, together with the known equation of state for /sup 4/He, allow a determination of the helium density as a function of age. The atomic density obtained in this way is approximately 2.0 times that of palladium metal, agreeing with densities inferred from dilatometric measurements of other metal tritides and also with predictions based on the concept of dislocation loop punching by highly overpressurized He bubbles. The /sup 3/He signal in the 22-month-old sample was sufficiently strong to allow a detailed study of melting as a function of temperature, and provides information on the distribution of densities over the ensemble of bubbles.
- Research Organization:
- Monsanto Research Corp., Miamisburg, OH (USA). Mound
- DOE Contract Number:
- AC04-76DP00053
- OSTI ID:
- 7143393
- Report Number(s):
- MLM-3519(OP); CONF-880505-30; ON: DE88012872
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AGING
BETA DECAY
BUBBLES
DECAY
EVEN-ODD NUCLEI
HELIUM 3
HELIUM ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAGNETIC RESONANCE
MELTING
MELTING POINTS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
PALLADIUM COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RESONANCE
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TRITIUM COMPOUNDS