The CaO–MgO–Al

2

O

3

–SiO

2

(CMAS) corrosion behavior of zirconia-based materials doped with different YO

1.5

contents (8YSZ

20YSZ

38YSZ

55YSZ) and pure yttrium oxide materials (Y

2

O

3

) at 1300 ℃ has been systematically studied. The results show that the CMAS corrosion behavior of zirconia-based materials with different yttria contents is significantly different. For 8YSZ and 20YSZ with low YO

1.5

content

the cor

rosion behavior is dominated by solutionreprecipitation and grain boundary corrosion. The former precipitates ZrO

2

grains

while the latter precipitates directly deposited on the surface of the original ZrO

2

to form a core-shell structure. With the increase of YO

1.5

content

the corrosion behavior gradually changed into reactive corrosion. The rapid reaction crystallization of 38YSZ and 55YSZ with CMAS molten salt formed a continuous dense protective layer containing apatite phase

which could effectively block the further erosion of CMAS molten salt. Moreover

the volume fraction of apatite phase in the protective layer formed by 55YSZ was more

which has better corrosion resistance to CMAS. Pure Y

2

O

3

samples can also react quickly with CMAS molten salt to form a dense pure apatite layer

which has good corrosion resistance to CMAS molten salt. Therefore

the resistance of thermal barrier coatings to CMAS molten salt corrosion can be controlled by adjusting the yttrium content in zirconia-based materials.