Time dependence of oxidation-induced microstructural changes in Nicalon- and Nextel-reinforced SiC
- Oak Ridge National Lab., TN (United States)
Thermogravimetric analyses and electron microscopy were used to characterize the high-temperature oxidation behavior of Nicalon- and Nextel 312-reinforced SiC with carbon interphases and no seal coatings. The results have been used to analyze the respective time dependencies of the oxidation reactions leading to carbon loss and the growth of solid products in the interfacial regions. While the overall oxidation responses of these two composite systems were qualitatively similar, the Nextel 312-reinforced SiC showed a longer period of carbon depletion and slower accumulation of oxide product in the interfacial areas. Consequently, this composite showed some resistance to brittle failure after oxidation times that completely embrittled the Nicalon/SiC. However, because of the reactions at the fiber-matrix interface, the incorporation of a more oxidation-resistant fiber in SiC with carbon interphases leads to only small improvements in high-temperature environmental stability.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 567489
- Report Number(s):
- CONF-960106--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Lifetime Response of a Hi-Nicalon Fiber-Reinforced Melt-Infiltrated SiC Matrix Composites
Ultrasonic characterization of oxidation mechanisms in Nicalon/C/SiC composites