Premium
Parameters affecting TGO growth rate and the lifetime of TBC systems with MCrAlY‐bondcoats
Author(s) -
Toscano J.,
Naumenko D.,
Gil A.,
Singheiser L.,
Quadakkers W. J.
Publication year - 2008
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200804134
Subject(s) - materials science , oxide , oxidizing agent , thermal barrier coating , microstructure , morphology (biology) , surface finish , surface roughness , metallurgy , composite material , layer (electronics) , chemistry , geology , paleontology , organic chemistry
In the present work different parameters which affect the oxide growth on MCrAlY‐bondcoats have been studied, in an attempt to find a reliable way to define the critical oxide thickness to failure of an EB‐PVD thermal barrier coatings (TBC). It was found that the variation of selected parameters such as oxidation temperature, surface roughness, and bondcoat thickness certainly alters the thermally grown oxide (TGO) growth rate. However, simultaneously the morphology, composition, and/or microstructure of the oxide are changed, which can affect the critical TGO thickness to failure in a TBC system. In contrast, the variation of the oxygen partial pressure of the oxidizing atmosphere led to different TGO growth rates without significantly changing the oxide morphology and composition. Comparing the TGOs grown at different rates in the specimens exposed to high pO 2 and low pO 2 atmospheres, it was estimated that at failure the oxide scales in both specimens have reached a similar critical thickness.