Particle Emission and Related Morphological Changes Occurring during the Sublimation of Graphitic Carbons.
Abstract
The mechanism of particle emission from hot graphitic carbons was studied by means of several heating and detection methods and by analysis of the emitted particles. The carbons studied are ATJS, Graph-I-Tite G, POCO9Q, spectrographic rod, pyrolytic graphite, and glassy carbon. All showed particulated mass loss in the range of 60 to 90% of the total mass loss. Generally, the results of this research are in accord with the conclusions of other investigators in that the mechanism of particulate mass loss for two-phase carbons is due mainly to preferential vaporization of the binder and the bursting of closed pores by entrapped gas. For single-phase carbons, the mechanism appears to involve undercutting resulting from inhomogeneities and the bursting of closed pores. Some of the graphitic material was transformed into linear carbon polymorphs, i.e., chaoite, carbon VI, and alpha + beta carbyne, and was emitted along with the graphitic particles. Data are cited that indicate that at approximately 3750 K particulate mass loss changes to mass loss as a result of the formation of liquid carbon.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 1975
- Accession Number
- ADA015863
Entities
People
- A. Greenville Whittaker
- P. L. Kintner
Organizations
- The Aerospace Corporation