EFFECT OF ISOTOPIC MASS ON VISCOSITY OF MOLTEN LITHIUM

Journal Article · Mon Oct 01 04:00:00 EDT 1962 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.128.6· OSTI ID:4782304

Ban, N T; Randall, C M; Montgomery, D J

The viscosity of the separated isotopes of molten lithium was measured by observing the damped oscillations of a torsion pendulum whose bob contained a spherical cavity filled with the material under test. For both Li/sup 6/ and Li/ sup 7/, the viscosity varies approximately as exp(B/T) over the temperature range 180 to 300 deg C; B has the value 458 deg K for Li/sup 6/ and 631 deg K for Li/ sup 7/. The viscosity of Li/sup 6/ is 4.18 plus or minus 0.05 mP (millipoise) at 180.4 deg C, its melting point; of Li/sup 7/, 6.00 plus or minus 0.05 mP at 180.7 deg C its melting point. A linear interpolation for Li/sup nat/(7.4% Li/ sup 6/ 92.6% Li) gives 5.86 mP at 180.5 deg C, only slightly lower than the value of 6.02 mP reported earlier by Andrade and Dobbs. The ratio of the viscosity of Li/sup 7/ to that of Li/sup 6/ is 1.44 at the melting point, in contrast with the value of 1.08, the square root of the mass ratio, as predicted on simple theoretical arguments. Actually, a thorough dimensional analysis shows that the viscosity varies as (mkT)/sup 1/2/ times a complementary dimensionless function containing--- among other arguments---the mass as a consequence of quantum effects. The function evidently depends strongly on these effects, as indicated not only by the present results on molten Li/sup 6/ and Li/sup 7/, but also by the results of others on other isotopically substituted liquids. (auth)

• Research Organization: Michigan State Univ., East Lansing
• NSA Number: NSA-16-030846
• OSTI ID: 4782304
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 128; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

LIQUID METALS
LITHIUM
LITHIUM 6
LITHIUM 7
MASS
MATERIALS TESTING
MATHEMATICS
MEASURED VALUES
MELTING POINTS
METALS, CERAMICS, AND OTHER MATERIALS
QUANTUM MECHANICS
ROTATION
SEPARATION PROCESSES
SPHERES
TEMPERATURE
TENSILE PROPERTIES
VARIATIONS
VIBRATIONS
VISCOSITY