Hot corrosion behavior of (Gd 0.9 Sc 0.1 ) 2 Zr 2 O 7 in V 2 O 5 molten salt at 700–1000 °C

Abstract Hot corrosion behavior of (Gd 0.9 Sc 0.1 ) 2 Zr 2 O 7 ceramic exposed to V 2 O 5 molten salt at 700–1000 °C was investigated, providing better understanding of its corrosion resistance as a promising thermal barrier coating. Obvious corrosion reaction occurred between (Gd 0.9 Sc 0.1 ) 2 Zr 2 O 7 and V 2 O 5 molten salt after 4 h heat treatment, corrosion products being temperature dependent. At 700 °C, large amount of Sc 2 O 3 doped ZrV 2 O 7 and GdVO 4 , together with a minor amount of Sc 2 O 3 -stabilized tetragonal ZrO 2 ( t -ZrO 2 ), formed on the sample surfaces. With the increase of the test temperature, Sc 2 O 3 doped ZrV 2 O 7 turned to decompose, leading to the formation of more t -ZrO 2 . At 900 °C and 1000 °C, the corrosion products were composed of GdVO 4 and t -ZrO 2 . The mechanism by which the corrosion reaction occurs is proposed based on phase diagrams and Lewis acid-base rule.