Hot corrosion behaviour of Yb2Si2O7 environmental barrier coatings in molten NaVO3 salt

The hot corrosion behaviour of Yb2Si2O7 environmental barrier coatings in molten salt NaVO3 was studied at 1000 degrees C-1300 degrees C. Results showed that YbVO4 and Yb2SiO5 were the main corrosion products, with rod-like and granular morphologies, respectively. The content of corrosion products was dependent on the corrosion temperatures. The content of YbVO4 decreased at 1000 degrees C-1200 degrees C and disappeared at 1300 degrees C. However, the content of Yb2SiO5 increased at 1100 degrees C-1300 degrees C and Yb2SiO5 was the main corrosion product at 1300 degrees C. The amorphous phase in the Yb2Si2O7 coating had a remarkable effect on the corrosion results. After heat treatment was conducted at 1400 degrees C for 12 h, the amorphous phase crystallised and then YbVO4 was the main corrosion product at 1300 degrees C. A model describing the formation of corrosion products was established on the basis of the corrosion products and the corrosion mechanism was discussed.

Automated summary

The study found that at high temperatures, Yb2Si2O7 environmental barrier coatings in molten salt NaVO3 would produce YbVO4 and Yb2SiO5 as the main corrosion products, and their content varied with the corrosion temperature. Furthermore, the amorphous phase in the Yb2Si2O7 coating had a significant impact on the corrosion results.