Microstructures and Properties of Laser-Glazed Plasma-Sprayed ZrO2-YO1.5/Ni-22Cr-10AI-1Y Thermal Barrier Coatings |
| |
Authors: | HL Tsai PC Tsai |
| |
Affiliation: | (1) Department of Mechanical Engineering and Technology, National Taiwan Institute of Technology, 10772 Taipei, Taiwan, R.O.C |
| |
Abstract: | Thermal barrier coatings (TBCs) consisting of two layers with various yttria contents (ZrO
2- YO1.5/Ni-22Cr-10Al- lY) were plasma sprayed, and parts of the various specimens were glazed by using a pulsed CO2 laser. All the specimens were then subjected to furnace thermal cycling tests at 1100 °C; the effect of laser glazing on
the durability and failure mechanism of the TBCs was then evaluated. From these results, two models were developed to show
the failure mechanism of as- sprayed and laser- glazed TBCs: model A, which is thermal-stress dominant, and model V, which
is oxidation-stress dominant. For top coats containing cubic phase, cubic and monoclinic phases, or tetragonal and a relatively
larger amount of monoclinic phases, whose degradation is thermal- stress dominant, laser glazing improved the durability of
TBCs by a factor of about two to six. Segmented cracks that occurred during glazing proved beneficial for accommodating thermal
stress and raising the tolerance to oxidation, which resulted in a higher durability. Thermal barrier coatings with top coats
containing tetragonal phase had the highest durability. Degradation of such TBCs resulted mainly from oxidation of the bond
coats. For top coats with a greater amount of monoclinic phase, thermal mismatch stress occurred during cooling and detrimentally
affected durability. |
| |
Keywords: | durability failure analysis fractograph laser glazing microstructure phase analysis plasma spraying thermal barrier coatings thermal cycling test yttria-stabilized zirconia |
本文献已被 SpringerLink 等数据库收录! |
|