Tensile stress and creep in thermally grown oxide

2006 ◽  
Vol 5 (5) ◽  
pp. 349-351 ◽  
Author(s):  
Boyd W. Veal ◽  
Arvydas P. Paulikas ◽  
Peggy Y. Hou
Keyword(s):  
Tensile Stress ◽  
Thermally Grown Oxide ◽  
Thermally Grown

scholarly journals Role of mechanical loads in inducing in-cycle tensile stress in thermally grown oxide

2012 ◽  
Vol 100 (11) ◽  
pp. 111906 ◽  
Author(s):  
Rene Diaz ◽  
Melan Jansz ◽  
Mitra Mossaddad ◽  
Seetha Raghavan ◽  
John Okasinski ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Thermally Grown Oxide ◽  
Mechanical Loads ◽  
Thermally Grown

scholarly journals Delayed Formation of Thermally Grown Oxide in Environmental Barrier Coatings for Non-Oxide Ceramic Matrix Composites

Coatings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 6 ◽  
Author(s):  
Hagen Klemm ◽  
Katrin Schönfeld ◽  
Willy Kunz
Keyword(s):  
Intermediate Layer ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Ceramic Matrix Composites ◽  
Thermally Grown Oxide ◽  
Oxide Ceramic ◽  
Gap Formation ◽  
Environmental Barrier ◽  
Sic Particles ◽  
Thermally Grown

The oxidation and corrosion behavior at elevated temperatures of a SiCF/SiC(N) composite with two plasma-sprayed environmental barrier coating (EBC) systems were studied. After both processes, the formation of a silica-based thermally grown oxide (TGO) layer was observed. The formation of this TGO caused two principal failure mechanisms of the EBC. Firstly, spallation of the EBC induced by stresses from volume expansion and phase transformation to crystalline SiO2 was observed. Water vapor corrosion of the TGO with gap formation in the top region of the TGO was found to be a second failure mechanism. After a burner rig test of the Al2O3-YAG EBC system, this corrosion process was observed at the TGO surface and in the volume of the Al2O3 bond coat. In the case of the second system, Si-Yb2Si2O7/SiC-Yb2SiO5, the formation of the TGO could be delayed by introducing an additional intermediate layer based on Yb2Si2O7 filled with SiC particles. The SiC particles in the intermediate layer were oxidized and served as getter to reduce the permeation of oxidants (O2, H2O) into the material. In this way, the formation of the TGO and the failure mechanisms caused by their formation and growth could be delayed.

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