| The turbine blades in aerospace are typically protected by a protective coating to improve the oxidation-resistant property of the substrate. Aluminized silicon coating has well oxidation-resistance. The Aluminized silicon coating on superalloy K4104 is prepared by using slurry process, the oxidation behavior of the coating is investigated by high temperature oxidation test under 1000℃ in air for 200h by means of OM, SEM, EDX, and the role of the silicon is also investigated. The kinetic analysis of the coating is done by the oxidation kinetics. The Aluminized silicon coating has better oxidation resistance than the Aluminized coating which can be observed through kinetics.Morphology and cross section micrograph of the Aluminized silicon coating is investigated by using SiRion SEM. Al2O3 is formed at the surface of the coating. The peeling of the coating at long time oxidation is obvious. But the new film of Al2O3 will form to protect the substrate. Aluminized silicon coating has transformed to three layers of α — Al2O3, Al-rich β -NiAl and Ni-rich β -NiAl and all of them have good adhesivity with the substrate.The proper content of silicon and its reasonable distribution played a significant role in suppressing the growth of β -NiAl phase. The silicon can also promote the transformation from β -phase to γ ' -phase. The Si-rich γ ' -phase has better oxidation resistance which can be compared with β -phase. The transformation from the β -phase to γ ' -phase can decrease the DBTT.The Silicon can accelerate the formation of M6C in which the W, Mo element involved, delaying the degradation of coating. The Si-rich barrier impedes Al and O diffusion into matrix of alloy, therefore rises oxidation resistance of Aluminized silicon coating at high temperature.
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