NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
On the effect of the Fe(2+)/Fe(3+) redox couple on oxidation of carbon in hot H3PO4Oxidation studies of graphite:glassy carbon composites have been carried out at 1 and 4.7 atm. pressures in conc. H3PO4 in the presence and absence of iron ions. The concentration of the acid was varied over 85-100 wt pct, and of the iron ions over 30-300 ppm; the temperature varied over 190-210 C. Unlike the effect of Fe, which has been observed to increase the corrosion of carbon in sulphuric acid, the corrosion in phosphoric acid was observed to be slightly decreased or not at all affected. This result arises because of the catalytic reduction of the oxidized surface groups of carbon by Fe(2+) ions. The catalytic reduction is possible because under the experimental conditions the redox potential of the Fe(2+)/Fe(3+) couple is lower than the open-circuit voltage of carbon.
Document ID
19870055403
Document Type
Conference Paper
Authors
Dhar, H. P. (Energy Research Corp. Danbury, CT, United States)
Christner, L. G. (Energy Research Corp. Danbury, CT, United States)
Kush, A. K. (Energy Research Corp. Danbury, CT, United States)
Date Acquired
August 13, 2013
Publication Date
March 1, 1986
Subject Category
INORGANIC AND PHYSICAL CHEMISTRY
Funding Number(s)
CONTRACT_GRANT: DEN3-290
Distribution Limits
Public
Copyright
Other