Accession Number : AD0260253

Title :   OXIDATION OF PYROLYTIC GRAPHITE BETWEEN 1250 F AND 1850 F

Corporate Author : WATERTOWN ARSENAL LABS MASS

Personal Author(s) : LEVY,MILTON

Report Date : MAY 1961

Pagination or Media Count : 1

Abstract : The oxidation of pyrolytic graphite was studied as a function of time and temperature. Pyrolytic graphite does not oxidize as rapidly as commercial graphite at temperatures below 1450 F but approaches that of commercial graphite at 1550 F. Oxidation of pyrolytic graphite proceeds preferentially in the c-direction contrary to expectation. The break in the Arrhenium plot for pyrolytic graphite occurring at 1550 F may beATTRIBUTED TO THE CHANGE IN CONTROL MECHANISM FROM CHEMICAL REACTIVITY TO DIFFUSION CONTROL. An activation energy of 37,180 calories per mol was calculated for a commercial graphite. The activation energy calculated for pyrolytic graphite was 23,350 calories per mol. The lower activation energy for pyrolytic graphite is associated with a lower reaction rate. This anomalous behavior is attributed to its lower porosity since a less porous material exposes a smaller surface area for molecular collisions. (Author)

Descriptors :   *GRAPHITE, CHEMICAL PROPERTIES, CHEMICAL REACTIONS, HIGH TEMPERATURE, MATERIALS, MICROSTRUCTURE, OXIDATION, PYROLYSIS

Distribution Statement : APPROVED FOR PUBLIC RELEASE