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U.S. Department of Energy
Office of Scientific and Technical Information

Rainbow test of advanced coatings for gas turbine blades and vanes

Technical Report ·
OSTI ID:6943552
The principal objective of this program was to carry out a comparative evaluation of the hot corrosion resistance of seven coatings applied to IN-738LC, IN-792 and MAR-M421 first-stage blades and eight coatings applied to FSX-414 and MAR-M509 first-stage vanes in an industrial gas turbine operating on a lower grade distillate fuel. The coatings evaluated included diffusion aluminides and metallic overlays of various compositions. Visual examination, optical metallography and scanning electron microscopy in conjunction with energy-dispersive x-ray analysis were used to evaluate the coated hot section components after a 7940 hour field test in a Centaur T-4000 engine. The metallic overlay coatings showed superior hot corrosion protection on blade platforms and blade airfoil stubs when compared with aluminide diffusion coatings. No differentiation in performance for individual representatives of these two groups of blade coatings could be discerned. The protectiveness of the vane overlay coatings was observed to increase with its chromium content. The metallic overlay vane coatings were more protective than the diffusion aluminides. An exception was the Cr-aluminide which showed comparable performance to a metallic overlay with intermediate chromium content on first-stage vanes. 28 refs., 54 figs., 14 tabs.
Research Organization:
Electric Power Research Inst., Palo Alto, CA (USA); Solar Turbines, Inc., San Diego, CA (USA)
OSTI ID:
6943552
Report Number(s):
EPRI-AP-5965; ON: TI88016217
Country of Publication:
United States
Language:
English