Determination of Fundamental Thermodynamic Properties of Constituent Materials and Performance Screening of Candidate Systems

This document reports the Phase I results of a program directed at a validation of thermochemical modeling, combined with selection supplemental experimental techniques, as a basis for screening materials for application in ultra-high temperature composites. The experimental techniques employed were laser probe spectroscopy and high temperature mass spectroscopy. Representative candidate constituents, drawn from oxides, carbides, borides, and intermetallics, were assessed under neutral and oxidizing conditions. The modeling approach can, in most cases, define probable limits for material stability. The experimental approaches provide a useful supplement to available data. Improved sensitivity in the laser spectroscopic measurement would be useful and the mass spectrometric technique would benefit from extended pressure sampling capability and reduced cellheater interactions. Keywords Refractory materials, Vaporization, Thermodynamics.