Preparation and self-healing performance of spherical α-Al2O3@MoSi2 particles using the precipitation method

摘要

alpha-Al2O3 was coated on the powder surface using the precipitation method to improve the pre-oxidation resistance of molybdenum disilicide in thermal barrier coatings (TBCs). The coating effects of four different aluminum sources (Al(NO3)(3 center dot)9H(2)O) to MoSi2 mass ratios were evaluated by viscosity and micro-morphology. The shell-forming effects on the powder size and post-treatment were thoroughly analyzed to meet the requirements for practical application in TBCs. The results showed that the precipitation method was superior to the sol-gel process in terms of the shell thickness obtained. Optimal shell-forming was generated at 1200 degrees C in an inert atmosphere. A bonding layer (Al6Si2O13) would be formed at the core-shell interface, further preventing oxidation penetration. The self-healing particles MoSi2@alpha-Al2O3 can effectively seal micro-cracks (width below 300 nm) because of the fluidity of SiO2 at working temperatures.

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