Study on corrosion cracking and oxidation mechanism of Inconel 718 burner of gasifier pulverized coal

•Thermal fatigue crack propagation was due to the repeated start-up and shutdown of gasifier.•Excessive δ phase weakens the matrix, and facilitates crack initiation and propagation.•The distribution of elements at different depths of the corrosion oxide layer was described.•Superalloys with better oxidation resistance should be selected.