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Influence of Distributed Particle Size on the Determination of the Parabolic Rate Constant for Oxidation by the Powder Method
Author(s) -
Shah Sandeep R.,
Saha Atanu,
Raj Rishi
Publication year - 2003
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.1151-2916.2003.tb00022.x
Subject(s) - constant (computer programming) , range (aeronautics) , particle size , particle (ecology) , materials science , reaction rate constant , analytical chemistry (journal) , mineralogy , statistical analysis , thermodynamics , mathematics , chemistry , kinetics , statistics , physics , composite material , chromatography , computer science , oceanography , quantum mechanics , programming language , geology
The established analysis for the study of oxidation using powder specimens is based on the assumption of monosized particles. The experiments, however, are conducted on powders with a distributed particle size. Here we present a statistical approach for the calculation of the rate constant for oxidation. The results of the analysis are applied to new data on oxidation studies of dense powders of silicon carbonitride amorphous ceramics. The monosized model requires a wide range of values for the rate constant to fit the short term and the long‐term data, leading to considerable ambiguity in the estimate of the parabolic rate constant, k p , for oxidation. In contrast the statistical model fits over the entire range of data, yielding a much more reliable value for k p . For example, the monosized approach gave a value in the range 19.7 × 10 −18 < k p < 2.7 × 10 −18 m 2 /s. In contrast, the statistical model yields a specific value of 4.5 × 10 −18 m 2 /s.