Influence of molten volcanic ash infiltration on the friability of APS thermal barrier coatings

Lokachari, Siddharth; Song, Wenjia; Yuan, Jieyan; Kaliwoda, Melanie und Dingwell, Donald B. (2020): Influence of molten volcanic ash infiltration on the friability of APS thermal barrier coatings. In: Ceramics International, Bd. 46, Nr. 8: S. 11364-11371

Abstract

Molten siliceous deposits originating from environmental debris such as volcanic ash, pose a severe threat to the longevity of Yttria-stabilized Zirconia thermal barrier coatings (YSZ TBCs). Surface wetting of TBCs by molten volcanic ash, followed by infiltration into the TBCs, leads to both thermo-chemical and thermo-mechanical TBC deterioration. In particular, the consequences of such wetting and infiltration on the thermo-mechanical properties remain unexplored to date. Here, in-situ molten volcanic ash wetting of TBCs subjected to thermal shock at 1300 degrees C has been performed for the first time. We experimentally characterized the generation of micro-cracks, whose origin lies in the high elastic modulus of the infiltrated region (similar to 262 GPa). Thermo-mechanical deterioration of the TBCs was due to the low fracture toughness and high thermal stresses (similar to 1.67 GPa) evaluated at the infiltrated region, which were responsible for the propagation of micro-cracks in the TBCs. We provide quantification and preliminary interpretation of the thermo-mechanical degradation of TBCs under these common thermal shock conditions.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften
• Themengebiete: 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• ISSN: 0272-8842
• Sprache: Englisch