Cp. Petit et Rj. Fruehan, INFLUENCE OF CHROMIUM AND NICKEL ON THE DISSOCIATION OF CO2 ON CARBON-SATURATED LIQUID-IRON, Metallurgical and materials transactions. B, Process metallurgy and materials processing science, 28(4), 1997, pp. 639-645
Citations number
18
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
At 1600 degrees C, under conditions where the rate was not significant
ly affected by liquid-phase or gasphase mass transfer, the rate of dis
sociation of CO2 was determined from the rate of decarburization of ir
on-based carbon-saturated melts containing varying amounts of chromium
and nickel, The rate was determined by monitoring the change in react
ed gas composition with an in-line spectrometer. The results indicate
that neither chromium nor nickel had a strong effect on the kinetics o
f dissociation of CO2 on the surface of the melt. Sulfur was found to
significantly decrease the rate, as is the case for alloys without chr
omium or nickel, and the rate constant is given by k = k(0)/1+K(s)a(s)
+ k(r) where k(0) denotes the chemical rate on pure iron, K-s is the
adsorption coefficient of sulfur, a(s) is the activity of sulfur corre
cted for Cr, and k(r) represents the residual rate at a high sulfur le
vel, The rate constants and adsorption coefficient were determined to
be: k(0) = 1.8 X 10(-3) mol/cm(2) s atm k(r) = 6.1 X 10(-5) mol/cm(2)
s atm K-s = 330 +/- 20 Experiments run at lower carbon contents showed
that only a very small quantity of chromium was oxidized, immediately
forming a protective layer. However, this oxidation occurred at a hig
her carbon content (2 pct) than what was expected from the thermodynam
ics.