| Abstract: |
In this article, an agglomerated and sintered powder of Y2O3-stabilized ZrO2 (YSZ) was introduced as a feedstock for atmospheric plasma spray (APS), and the bimodal structured thermal barrier coatings with different contents of nanostructure were deposited. In order to study the effect of nanostructure content on thermal shock resistance of the coating, the water quenching method was carried out. The results show that the thermal cycle life of the coating is obviously influenced by the microstructure of the coating. When the content of nanostructure is relatively low (about 39%), the coating shows high microhardness and poor thermal cycle life (failure at 11 cycles); however, when the content of nanostructure is relatively high (about 60%), the coating shows lower microhardness and improved thermal cycle life (failure at 42 cycles); the coating with medium nanostructure (about 52%) shows the best thermal shock resistance (unfailure at 50 cycles). The thermal stability of nanostructured coating was also investigated. After heat treatment at 1300oC for 10h, the nano particle size grew up, and the hardness of the coating increased obviously. That indicated the sintering effect of the nanostructured coating has been abserved.
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