Abstract
Thermal barrier coatings(TBCs)applied in aero-engines tend to be attacked by molten calcia-magnesia-alumino-silicate(CMAS)at high operating temperatures.Yttria-stabilized zirconia(YSZ)coatings with quasi-columnar microstructure were fabricated by plasma spray physical vapor deposition(PS-PVD)technique.The chemical changes,microstructural transformation,mechanical properties and degradation mechanisms of the CMAS-interacted TBCs in the thermal cycling tests were investigated.Feathered YSZ grains were dissolved in the CMAS melts,and then the ZrO2 grains were reprecipitated with spherical shape,accompanying with phase transfor-mation from tetragonal(t)to monoclinic(m).The thermal cycling tests reveal that the YSZ coating fails at the early stage due to the attack of CMAS.The fractures in intra-columns lead to partial spallation of the coatings.The failure of the coating occurs at the interfaces between thermally grown oxides(TGO)layer and YSZ topcoat;especially,the hardness and Young's modulus of the YSZ coatings increase intensively,as the coatings were infil-trated by the CMAS for a long time.
基金项目
National Natural Science Foundation of China(51590894)
National Natural Science Foundation of China(51425102)
National Natural Science Foundation of China(51231001)
NETL
NSTL
万方数据