Session: 03-07-01 Materials for Extreme Environment I

Paper Number: 107437

107437 - The Effect of Oxidation in Environmental Barrier Coatings Subject to Foreign Object Damage 

Oxidation and foreign object damage (FOD) are two key failure modes for environmental barrier coatings (EBCs). For EBCs with a silicon (Si) bond coat, a thermally grown oxide (TGO) layer forms at the EBC – bond coat interface. The TGO layer is the weak interface, and directly influences the life of the EBC. Moreover, FOD has been shown to cause significant subsurface damage resulting in delamination or spallation of the EBC which can occur at the EBC - bond coat interface or the bond coat - substrate interface. The purpose of this work is to investigate the synergistic effects of oxidation and FOD in a ytterbium disilicate (Yb₂Si₂O₇) EBC. FOD testing is conducted on as-deposited and steam oxidized samples at room temperature using a 1.59-mm hardened steel ball projectile. The resulting damage is characterized by optical profilometry and scanning electron microscopy (SEM). Additionally, a mechanical assessment of the EBC bond strength in the presence of a growing TGO is presented.

Presenting Author: Leland Hoffman HX5

Presenting Author Biography: Mechanical engineer employed by HX5, LLC at the NASA Glenn Research Center in Cleveland, Ohio.

Authors:

Leland Hoffman HX5
Michael Presby NASA Glenn Research Center
Jamesa Stokes NASA Glenn Research Center
Bryan Harder NASA Glenn Research Center
Jon Salem NASA Glenn Research Center