Accession Number:

AD0780111

Title:

Thermodynamic Properties of High Temperature Materials.

Descriptive Note:

Final rept.,

Corporate Author:

PHILCO-FORD CORP NEWPORT BEACH CALIF AERONUTRONIC DIV

Personal Author(s):

• Potter,Norman D.
• Piper,Gerry

Report Date:

1974-03-31

Pagination or Media Count:

32.0

Abstract:

A careful equilibrium study of the Si-N vapor system of mass spectrometry has shown that the only important binary Si-N vapor species is the previously known Si2N. Its heat of formation is 83 plus or minus 4 Kcalmole. No ternary Si-N-O nor Si-C-N species were found. The accepted heats of formation of Si2Cg and SiC2g were confirmed as was the heat of formation of Si3g. The vaporization behavior of Si3N4c was studied and found to be quite complex. From a study of the vaporization of VF3 it was found that the primary vapor species at VF3g with minor, and approximately equal partial pressures of VF2g and VF4g. Due to sample impurity little could be inferred from the vaporization of VF4. From these experiments and estimates of the auxiliary heats and thermal function, heats of formation were estimated. Modified author abstract

Descriptors:

• *Vaporization
• *Silicon nitrides
• Chemical equilibrium
• Heat of formation
• Gases

Subject Categories:

• Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE