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Evaporation of Zinc Oxide from Spinel Solid Solutions in Vacuum
Author(s) -
KOUMOTO KUNIHITO,
YANAGIDA HIROAKI,
MIZUTA SUSUMU
Publication year - 1980
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.1151-2916.1980.tb10639.x
Subject(s) - spinel , evaporation , torr , zinc , decomposition , diffusion , reaction rate constant , oxide , vacuum evaporation , analytical chemistry (journal) , materials science , thermal decomposition , chemistry , inorganic chemistry , metallurgy , kinetics , thin film , thermodynamics , nanotechnology , physics , organic chemistry , chromatography , quantum mechanics
The mechanism for the evaporation of ZnO from powders of (Zn 02 Co 0.8 )O·Al 2 O 3 (ZCA) and (Zn 0.2 Ni 0.8 )O·Al 2 O 3 (ZNA) spinels was studied at 1335° to 1500°C in vacuum of 3×10 −5 to 10 −4 torr. The evaporation of ZnO occurred in two stages: at a constant rate in the first and a decreasing rate in the second. The rate‐determining process was analyzed as a decomposition reaction at the first stage and as the conjugated process of decomposition reaction and diffusion in the solid at the second. The evaporation rate constant and surface emissivity showed a similar dependence on temperature. The ratio of the concentration of ZnO at the surface to the initial concentration was =0.7 when the first stage of evaporation changed to the second.