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Reaction Kinetics of Porcelain Enamel‐Metal Systems
Author(s) -
SPRIGGS R. M.,
FRIEDBERG A. I.
Publication year - 1960
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.1151-2916.1960.tb14593.x
Subject(s) - cobalt , metal , nickel , arrhenius equation , inorganic chemistry , activation energy , materials science , copper , valence (chemistry) , chemistry , chemical kinetics , kinetics , reaction rate , analytical chemistry (journal) , metallurgy , catalysis , physics , organic chemistry , chromatography , quantum mechanics , biochemistry
The reaction kinetics of the elevated‐temperature fusion reactions between various powdered metals and finely divided sodium borosilicate porcelain enamel frits were studied. The powdered metals employed were nickel, cobalt, iron, and magnesium; the metallic ions were copper, nickel, cobalt, and iron. These reaction studies were made as a function of time, temperature, and concentration of the metallic ion in the frit. Quantitative X‐ray diffraction was used to determine the amount of metallic ion in each reaction which had been reduced to the metallic state by the added metal. Specific reaction rates were calculated, their temperature dependence was demonstrated by use of the Arrhenius equation, and activation energies were determined from the slope of these curves. The over‐all results were in accordance with the general theory of chemical kinetics, with increases in time, temperature, and metallic‐ion content resulting in increases in the amount of metallic ion reduced, except for those frits containing the iron ion, which, when coupled with cobalt or nickel metal, resulted in probable reduction of the iron ion to a lower valence, but not to the metallic state. Inversions in the order of magnitude of reaction rates for two different metals with the same metallic ion frequently occurred at certain times and temperatures. Reactions such as Fe + COO (NiO) = FeO + Co (Ni), which might take place at an enamel‐metal interface, were strongly favored to the right and very little tendency existed for the reverse to occur.