Publication: Development of Sic-Sio2 diffusion barrier coating on nickel-based superalloy prepared by slurry sintering technique for high temperature applications
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Date
2025-08-07
Authors
Pigitra, Huang Xin Nie
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Abstract
Nickel-based superalloys like Inconel 625 are extensively used in high- temperature applications due to their mechanical strength and oxidation resistance. However, surface degradation due to interdiffusion and oxidation limits its long-term performance. This study aims to develop a SiC–SiO2 diffusion barrier coating using slurry sintering technique to reduce interdiffusion and improve oxidation resistance. A slurry was formulated by mixing SiC and SiO2 powders in a potassium silicate solution and applied to Inconel 625 substrates using a brush coating method. The coated samples were sintered at 800 °C, 900 °C, and 1000 °C under argon atmosphere. Coatings were analyzed using SEM, EDX, XRD, and Vickers hardness testing. Among the tested sintering temperatures, the coating processed at 900 °C exhibited the most favorable results, showing a uniform and dense microstructure with an average thickness of 166.6 ± 9.76 μm and no visible cracks or delamination. XRD confirmed SiC and SiO2 phases, and EDX showed uniform elemental distribution. Hardness values also increased due to improved densification. In conclusion, the slurry-sintered SiC–SiO2 coating developed at 900 °C demonstrated good microstructural continuity, surface uniformity, and strong interfacial bonding with the Inconel 625 substrate. These findings indicate the potential of this composite system to serve as a diffusion barrier layer, warranting further investigation under high-temperature oxidation.
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