Application of Abradable Coating to Improve Gas Turbine Efficiency

Gas turbine efficiency is highly dependent on minimizing the clearance between rotating blades and stationary components, such as between first stage blades and shroud blocks. Abradable coatings are critical in achieving this goal by allowing blades to cut into the coating during operation, maintaining optimal clearance. This paper presents a comprehensive study on the application of plasma spray abradable coatings for Frame 6B gas turbines. The research covers the coating design, process development, material selection, and quality testing. The proposed coating system, consisting of AMDRY 962 (bond coat), 204F (interlayer coat), and 2395/2460 (abradable layer), was optimized to achieve desired porosity, adhesion, and thermal properties. The findings demonstrate the effectiveness of the coating system in reducing blade-tip clearance and improving turbine efficiency. The study also highlights the challenges of directional vertical cracks (DVC) and proposes solutions for future optimization.