Diffusion in polycrystalline Y/sub 2/O/sub 3/ and Er/sub 2/O/sub 3/

Technical Report · Wed May 01 04:00:00 EDT 1968

DOI:https://doi.org/10.2172/6613946· OSTI ID:6613946

Berard, M F

A tracer sectioning technique was employed to measure cation self-diffusion coefficients in fully dense polycrystalline materials under oxidizing conditions. Results are D = 1.65x10/sup -2/ exp(-69,200/RT) cm/sup 2//s for Y/sub 2/O/sub 3/ (1400 to 1670/sup 0/C), and D = 1.48 exp(-102,200/RT) cm/sup 2//s for Er/sub 2/O/sub 3/ (1400 to 1700/sup 0/C). The greater activation energy for erbium diffusion in erbia is attributed to a mass effect. Oxygen diffusion coefficients were extracted from observations in the reoxidation of small single crystals of uniformly reduced oxides produced by vacuum fusion. The oxidation process proceeded by the development of a fully oxidized external shell, the growth of which was rate-limited by diffusion of interstitially dissolved oxygen through the oxidized layer to a sharp interface with the reduced material. The growth of the oxidized shell was followed by means of a thermobalance. Oxygen diffusion coefficients were calculated to be D = 6.01x10/sup -6/ exp(-19,600/RT) cm/sup 2//s for Y/sub 2/O/sub 3/ (1064 to 1276/sup 0/C), and by D = 4.76x10/sup -5/ exp(-30,100/RT) cm/sup 2//s for Er/sub 2/O/sub 3/ (1060 to 1292/sup 0/C).

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6613946
• Report Number(s): IS-T-230; ON: DE84016919
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
CHALCOGENIDES
CRYSTALS
DIFFUSION
ELEMENTS
ERBIUM COMPOUNDS
ERBIUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
POLYCRYSTALS
RARE EARTH COMPOUNDS
SELF-DIFFUSION
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES