About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
High Temperature Oxidation of Metals and Ceramics
|
Presentation Title |
Mo-Si-B Coatings for Protection of SiC-based Materials in High Temperature Active Oxidation Environments |
Author(s) |
Jeffrey R. Becker, John H Perepezko |
On-Site Speaker (Planned) |
Jeffrey R. Becker |
Abstract Scope |
One of the most demanding engineering challenges for sustained hypersonic flight is the development of a suitable thermal protection system for leading edges that experience high temperatures and low pO<sub>2</sub> environments. While SiC shows promise, it is rapidly consumed in hypersonic conditions due to active oxidation – a mechanism that occurs at high temperatures and low pO<sub>2</sub>, leading to the production of volatile SiO(g) that breaks down the SiO<sub>2</sub> protective layer. In past work, Mo-Si-B coatings have been shown to improve the oxidation resistance of SiC in air at elevated temperatures by forming an aluminoborosilica scale. In this study, the compatibility of Mo-Si-B coatings on SiC is evaluated by isothermal oxidation experiments conducted at T=1500°C and pO2=~10<sup>-5</sup> atm. Mo-Si-B coatings exhibit robust performance under these conditions - an active oxidation range for other silica formers. Additionally, coatings without Al or B showed reduced microstructural stability and poorer performance than aluminoborosilica. |