Preparation and characterization of La-doped Y3Al5O12 as a potential protective coating material against CMAS corrosion

Mitigating calcium-magnesium-aluminum-silicate (CMAS) corrosion attack on thermal barrier coatings (TBCs) has attracted increasing interest. In this study, (Y1-xLax)3Al5O12 (x = 0, 0.1, 0.2, 0.3) were synthesized by the chemical co-precipitation method. The La-doped Y3Al5O12 was composed of Y3Al5O12 and LaAlO3 phases. As the La3+ doping concentration increased, the content of the LaAlO3 phase gradually increased. Compared to undoped Y3Al5O12, the fracture toughness and Vickers hardness of Y3Al5O12 doped with 20 mol% La3+ increased by 54.9 % and 72.5 % respectively, reaching 2.88 MPa & sdot;m1/2 and 18.03 GPa. The thermal expansion coefficient of Y3Al5O12 doped with 30 mol% La3+ reached 9.79 x 10-6/K at 1000 degrees C, which was 7. 34 % higher than that of the un-doped Y3Al5O12. The CMAS corrosion resistance of (Y1-xLax)3Al5O12 gradually improved with the increase of LaAlO3 content. LaAlO3 promoted the formation of a dense apatite-spinel reaction layer and effectively inhibited the penetration of CMAS. (Y1-xLax)3Al5O12 (x = 0.1, 0.2, 0.3) can act as a potential protective coating material against CMAS corrosion.

Automated summary

This study synthesized (Y1-xLax)3Al5O12 (x = 0, 0.1, 0.2, 0.3) materials by doping lanthanum ions, and found that the doped materials exhibited improved mechanical properties and thermal expansion coefficient, as well as enhanced resistance to CMAS corrosion. These materials have potential applications.