Accession Number:

ADA021168

Title:

Determination of Graphite-Liquid-Vapor Triple Point by Laser Heating

Descriptive Note:

Interim rept.

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA AEROPHYSICS LAB

Personal Author(s):

• Gokcen, N. A.
• Chang, E. T.
• Poston, T. M.
• Spencer, D. J.

Report Date:

1976-01-30

Pagination or Media Count:

60.0

Abstract:

A technique was developed for measuring the melting temperatures of graphite, and the graphite-liquid-vapor triple point by means of continuous HF laser in the pressure range 120 to 215 atm. The triple point was found to be 120 or - 10 atm and 4130 or - 30 K for pyrolytic graphite. The results with neon, argon, and krypton as pressurization gases were concordant. A vapor-solid- liquid phase diagram was obtained in the vicinity of triple point. Photomicrography, electron micrography, x-ray diffraction, and ion microprobe mass analysis were used to characterize the structure of frozen liquid droplets, the pyrolytic graphite matrix, and condensed vapor.

Descriptors:

• *MELTING POINT
• *PYROLYTIC GRAPHITE
• ARGON
• ELECTRON MICROSCOPY
• HYDROGEN FLUORIDE
• IONS
• KRYPTON
• LASERS
• NEON
• PHASE DIAGRAMS
• VAPOR PRESSURE
• X RAY DIFFRACTION

Subject Categories:

• Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE