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Ytterbium Cation Diffusion in Yttrium Aluminum Garnet (YAG)—Implications for Creep Mechanisms
Author(s) -
JiménezMelendo Manuel,
Haneda Hajime,
Nozawa Hoshiteru
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb01014.x
Subject(s) - grain boundary diffusion coefficient , yttrium , ytterbium , materials science , effective diffusion coefficient , analytical chemistry (journal) , atmospheric temperature range , activation energy , diffusion , grain boundary , lattice diffusion coefficient , mineralogy , oxide , thermodynamics , composite material , metallurgy , chemistry , doping , microstructure , medicine , optoelectronics , physics , chromatography , magnetic resonance imaging , radiology
The lattice and grain‐boundary diffusion coefficients of ytterbium, which substitutes for yttrium, have been determined in high‐purity, stoichiometric yttrium aluminum garnet (YAG) polycrystals in the temperature range 1400°–1550°C, in air. Ytterbium oxide thin films were produced on the YAG surfaces by a dipping method. After diffusion treatments, the penetration profiles were established by secondary ion mass spectroscopy, and the diffusion coefficients were calculated from the thin‐film solution of Fick's equation. The difference between the volume and grain‐boundary diffusion coefficients is ∼5 orders of magnitude in the temperature range studied. The cation activation energies (∼550 kJ/mol) are much larger than those for oxygen (∼300–350 kJ/mol). The effective diffusion coefficient deduced from high‐temperature deformation data reported in the literature for YAG polycrystals, assuming grain‐boundary sliding accommodated by volume diffusion, is in excellent agreement, both in magnitude and activation energy, with the cation diffusion data.