Zirconia based laser-glazed TBC properties and thermal cycling and erosion resistance

Zirconia based laser-glazed TBC properties and thermal cycling and erosion resistance Mr. Nikolay Zaitsev, TSPC LLC., Moscow, Russia Dr. Ivan Mazilin, TSPC LLC., Moscow, Russia Dr. Lev Baldaev, TSPC LLC., Moscow, Russia Thermal barrier coating (TBC) laser treatment of ceramic topcoat shown to be one of the most efficient ways to improve air plasma sprayed (APS) coatings properties saving thermal conductivity comparatively low. Diode lasers known to have the most uniform energy distribution (“top-hat”) let alone that it is most efficient and cost-effective source type to use. In the present paper standard two-layer TBC system (Ni-Co-Cr-Al-Y bondcoat and 7YSZ ceramic topcoat) was sprayed on the surface of Ni-based superalloy substrates using APS. Coatings then subjected to laser treatment to enhance coating lifetime. Diode laser source with special optics used to perform the treatment. As a result, the glazed layer formed in the ceramic topcoat. According to SEM the glazed layer has specific axial texture structure and vertical cracks network. Laser glazed coating has higher strain tolerance than as-sprayed coating. Thermal cycling, high temperature exposure and erosion resistance of glazed coating showed better results comparing to as sprayed