Hot Corrosion Behaviour Of Yb(2)Si(2)O(7 )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.