Hot corrosion behavior of Yb2Si2O7 ceramic by NaVO3 at 500 °C to 900 °C

Abstract

The hot corrosion behavior of Yb2Si2O7 bulk exposed to NaVO3 was investigated at 500–900°C. Results indicated that the hot corrosion reaction could occur at 500°C, the corrosion products were composed of YbVO4 and SiO2 at 500–900°C. The content of YbVO4 and SiO2 in the corrosion product at 500°C was small and the crystal size of YbVO4 was fine. As temperature increased, a continuous and dense corrosion layer could be formed on the bulk surface, which prevented the hot corrosion reaction from occurring dramatically. The hot corrosion reaction products mainly consisted of rod-shaped YbVO4 beyond 600°C. Since the corrosion reaction driving force increased with temperature, the rod-like YbVO4 crystals tended to go from slender to plump; moreover, both ends changed from irregular lamination to regular quadrangular pyramid shape; also SiO2 crystals partly changed from flocculent to ellipsoid shape. The hot corrosion mechanisms of Yb2Si2O7 bulk exposed to NaVO3 at 500–900°C were investigated based on the corrosion products.

Keywords

• hot corrosion
• ytterbium silicate
• navo3
• corrosion mechanism
• ceramic