Hot corrosion behavior of Ti3SiC2 in the mixture of Na2SO4–NaCl melts

The corrosion behavior of polycrystalline Ti3SiC2 was studied in the mixture of Na2SO4–NaCl melts with various mass ratios at 850 °C. The results demonstrated that Ti3SiC2 suffered from serious hot corrosion attack in the mixture of Na2SO4–NaCl melts when the concentration of Na2SO4 was higher than 35 wt.%. A large amount of corrosion products spalled from specimens during the tests and obvious mass loss was observed. Hot corrosion of Ti3SiC2 would become severe because NaCl had lower melting-point and caused Na2SO4–NaCl mixture melted below 850 °C. However, when the concentration of Na2SO4 was lower than 25 wt.% in the mixture, a protective oxide layer (SiO2 + TiO2) formed on the substrate, the corrosion rate of Ti3SiC2 became quite slow and slight mass gain was observed, the corrosion products did not spall from substrate at 850 °C. The microstructure and phase composition of the corroded samples were investigated by SEM/EDS and XRD.