INTERSPLAT OXIDATION OF ATMOSPHERIC PLASMA SPRAYED MCRALY COATINGS
2014 (English)In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2014, VOL 6, AMER SOC MECHANICAL ENGINEERS , 2014, no V006T22A017Conference paper (Refereed)
MCrAlY coatings and thermal barrier coatings (TBC) are commonly used in gas turbines to prolong the life of structural parts. The atmospheric plasma spray (APS) process yields coatings with a typical splat-on-splat structure which oxidizes at intersplat boundaries during high-temperature exposure. A study was performed to establish the influence of intersplat oxidation on Al depletion. It was found that the P -depletion based life may be overestimated by a factor of 1.8-18 if intersplat oxidation is not considered. Two different mechanisms of intersplat oxidation were observed: At high temperature (1050 degrees C), a fraction of the intersplat boundaries remained in contact with the coating surface and oxidized with the same kinetics as the surface oxides. At lower temperature (900 degrees C), intersplat oxidation occurred by considerable slower growth rates than surface oxidation. The mechanisms behind intersplat oxide growth was further studied by O diffusion calculations.
Place, publisher, year, edition, pages
AMER SOC MECHANICAL ENGINEERS , 2014. no V006T22A017
IdentifiersURN: urn:nbn:se:liu:diva-122451ISI: 000362239800075ISBN: 978-0-7918-4575-2OAI: oai:DiVA.org:liu-122451DiVA: diva2:866548
ASME Turbo Expo: Turbine Technical Conference and Exposition