Inventors:
Bangalore Aswatha Nagaraj - West Chester OH
Jeffrey Lawrence Williams - Cincinnati OH
John Frederick Ackerman - Laramie WY
Assignee:
General Electric Company - Schenectady NY
International Classification:
B32B 1504
US Classification:
428469, 428697, 428699, 428701, 428702, 428472, 428336, 416241 B, 427250, 42725519, 42725521, 42725523, 42725531, 4272557, 20419216
Abstract:
A protective coating system and method for protecting a thermal barrier coating from CMAS infiltration. The coating system comprises inner and outer alumina layers and a platinum-group metal layer therebetween. The outer alumina layer is intended as a sacrificial layer that reacts with molten CMAS, forming a compound with a melting temperature significantly higher than CMAS. As a result, the reaction product of the outer alumina layer and CMAS resolidifies before it can infiltrate the TBC. The platinum-group metal layer is believed to serve as a barrier to infiltration of CMAS into the TBC, while the inner alumina layer appears to enhance the ability of the platinum-group metal layer to prevent CMAS infiltration.